CN103154201B - Method for decomposing organic substance into lower molecules, and method for utilizing exhaust gas generated by metallurgical furnace - Google Patents

Abstract

A method for decomposing an organic substance into lower molecules is provided. In this method, an organic substance is decomposed into lower molecules and converted into gaseous fuel, liquid fuel, or the like. In this process, the organic substance can be efficiently reformed and decomposed into lower molecules using a stable supply of gas to obtain a reformate containing minimal amounts of heavy fractions or carbonaceous materials and large amounts of light fractions. The method can be implemented using relatively simple equipment. An excess of steam is added to an off-gas (g0) that contains carbon monoxide and is generated by a metallurgical furnace, and a shift reaction is performed to obtain a mixed gas (g) containing the hydrogen and carbon dioxide generated by the shift reaction and the steam not consumed by the shift reaction. The mixed gas (g) is brought into contact with the organic substance, and the organic substance is reformed and decomposed into lower molecules. Reforming of the organic substance involves four simultaneously occurring reactions: hydrogenation, hydrogenolysis, steam reforming, and carbon dioxide reforming, allowing decomposition of the organic substance into lower molecules to be facilitated efficiently even at a relatively low reaction temperature.

Description

Method for reducing molecular weight of organic substances and method for utilizing exhaust gas from metallurgical furnaces

technical field

The first invention of the present application relates to a method of modifying organic substances to reduce their molecular weight, which is used to convert organic substances such as waste plastics into gaseous fuels, liquid fuels, and the like. In addition, the second invention of the present application relates to a method for utilizing waste gas produced by a metallurgical furnace, which method uses the method for reducing the molecular weight of the above-mentioned organic substances, and the method is used to reduce the amount of combustion emissions of the waste gas produced by the metallurgical furnace (combustion emission Combustion diffusion quantity), the waste gas is effectively used in the following processes: used to modify organic substances such as waste plastics to reduce their molecular weight, and convert them into gaseous fuels or liquid fuels.

Background technique

Nowadays, waste plastics, oily sludge, waste oil, etc. are mostly incinerated. However, there is a high burden on the environment due to the generation of CO ₂ etc. during incineration, and there is also a problem of thermal damage to the incinerator, so the establishment of chemical recycling technology is required.

Among the chemical recycling technologies, various researches have been conducted centering on waste plastics as technologies for converting organic substances into gaseous fuels or liquid fuels, and the following proposals have been proposed, for example.

Patent Document 1 discloses a method in which coke oven gas (COG) having a hydrogen concentration of 60% by volume or more, preferably 80% by volume or more, and a temperature of 600°C or higher is reacted with organic substances such as waste plastics to efficiently convert Hydrocracking and gasification of organic substances increase the heat of COG.

In addition, Patent Document 2 discloses a method of decomposing waste plastics into liquid fuel at a temperature of 350 to 500° C. using petroleum fluid contact catalyst (FCC) as a heat medium and catalyst.

In addition, Patent Document 3 discloses a method in which when thermally decomposing RDF or wood, etc., the gas produced by thermal decomposition is steam-reformed, and the hydrogen concentration is increased by the steam reformation. The gas circulates through the pyrolysis section, and thermal decomposition is carried out in the gas atmosphere with increased hydrogen concentration.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2007-224206

Patent Document 2: Japanese Patent Laid-Open No. 2010-013657

Patent Document 3: Japanese Patent Laid-Open No. 2001-131560

Patent Document 4: Japanese Patent Laid-Open No. 2000-283658

Contents of the invention

The problem to be solved by the invention

However, the above-mentioned prior art has the following problems.

First, regarding Patent Document 1, the hydrogen concentration in COG is 60% by volume or more, and it is limited to the final stage of carbonization even in the coal pyrolysis process. Therefore, in the method of Patent Document 1, it is necessary to switch the gas flow path at the end of carbonization. , Supply COG above 600°C containing a large amount of dust to the waste plastic hydrocracking reactor. However, under such severe conditions, it is difficult to make the channel switching valve continue to operate stably for a long period of time. In this sense, it can be said that this technology is not practical. In addition, in order to achieve effective gasification of waste plastics, it is necessary to continuously supply COG containing more than 60% by volume of hydrogen to the hydrocracking reactor. For this reason, it is necessary to install a hydrogen concentration meter and a flow path switching valve in each carbonization chamber. Equipment costs increase.

In addition, although the method of Patent Document 2 promotes catalytic cracking and aromatization by adding an FCC catalyst, since the reaction is carried out under the flow of an inert gas, a total of 13 mass % of heavy oil components and coke are generated (Example 1). The production technology of high-quality fuel cannot be said to be at a satisfactory level.

In addition, the gas generated by the method of Patent Document 3 is mainly H ₂ , CO, and CO ₂ , which has a combustion heat of about 1800 kcal/Nm ³ slightly lower than the exhaust gas generated by a metallurgical furnace, and its value as a gas fuel is limited.

In the prior art for converting organic substances such as waste plastics into gaseous fuels and liquid fuels, there are problems as described above, and it is desired to propose a method for reducing the molecular weight of organic substances. The method for reducing the molecular weight of organic substances The gas that can be supplied stably can be used to effectively modify and lower the molecular weight of organic substances to obtain heavy components and modified products with less carbon and a large amount of light components, and it can be implemented with relatively simple equipment.

On the other hand, with regard to effective utilization of exhaust gas generated from metallurgical furnaces, the following problems currently exist. That is, various metallurgical furnaces that perform intermittent production, such as a converter, intermittently generate a large amount of waste gas in synchronization with production. For example, a converter generates exhaust gas with a CO concentration of about 50 to 70% by volume at an instantaneous flow rate of about 100,000 to 300,000 Nm ³ /hr. However, since the blowing time is about 10 to 30 minutes, for example, when the instantaneous flow rate is 100,000 Nm ³ /hr, the time average flow rate including the time without blowing is about 17,000 to 50,000 Nm ³ /hr . Since the lower heat of combustion is about 2000kcal/Nm ³ , converter gas is effectively used as fuel in ironworks and the like. However, because it is generated intermittently, the exhaust gas must be used at a flow rate lower than the previous time-average flow rate, which is substantially out of balance with the instantaneous flow rate. Therefore, there is a time when it cannot be completely accommodated in the gas receiver, and there is a problem that diffusion combustion must be performed from the exhaust gas combustion flue.

In view of such a problem, as a method of using converter gas for suppressing diffusion combustion of converter gas, Patent Document 4 discloses a method in which converter gas is supplied to an apparatus that reacts CO and methanol to synthesize acetic acid, and utilizes converter gas The CO in the acetic acid is used as the raw material.

However, acetic acid is not an essential auxiliary raw material in ironworks because it needs to be sold outside. When there is no demand for acetic acid, it is necessary to reduce the production amount, and there is a problem that the emission of converter gas cannot be suppressed.

Therefore, an object of the present invention is to provide a method for reducing the molecular weight of organic substances, which can convert organic substances such as waste plastics into gaseous fuels, liquid fuels, etc. by using a gas that can be stably supplied. Efficient modification and low molecular weight can be used to obtain heavy components and modified products containing less carbon and a large amount of light components, and can be implemented with relatively simple equipment.

In addition, another object of the present invention is to provide a method for utilizing exhaust gas generated from a metallurgical furnace, which can effectively utilize the exhaust gas generated from a metallurgical furnace with a stable usage amount, and stably reduce combustion emissions.

way of solving the problem

In order to solve the above-mentioned problems, the inventors of the present invention conducted repeated studies, and obtained the following findings as a result. First, in order to solve the first problem, the following method is effective: add excess water vapor to the waste gas containing carbon monoxide generated in the metallurgical furnace to carry out the shift reaction, and use the gas after the shift reaction, that is, the gas in the shift reaction The mixed gas of generated hydrogen, carbon dioxide and residual water vapor modifies high molecular weight organic substances to reduce their molecular weight. It was also found that there is a preferable range for the composition of the mixed gas for modifying organic substances (shift reaction product gas).

In addition, it has been found that the second problem can be solved by effectively utilizing exhaust gas generated from a metallurgical furnace containing carbon monoxide as a raw material gas for a specific process for reducing the molecular weight of organic substances as described above. That is, gaseous fuels and liquid fuels obtained by using gas generated in a metallurgical furnace containing carbon monoxide as a raw material gas for the above-mentioned specific organic substance low molecular weight process are indispensable in metal smelting facilities such as ironworks , Since it is a fuel that is often consumed, there is no need to reduce its production amount as needed, so the gas generated in the metallurgical furnace can be stably used (consumed) as a raw material gas, so the combustion of the gas generated in the metallurgical furnace can be stably reduced The amount of release.

The present invention was completed based on the above findings, and its gist is as follows.

[1] A method for reducing the molecular weight of organic substances, the method comprising: adding an excessive amount of water vapor to exhaust gas (g ₀ ) containing carbon monoxide generated in a metallurgical furnace to cause a shift reaction to form a gas containing shift reaction A mixed gas (g) of hydrogen, carbon dioxide, and water vapor not consumed in the shift reaction is brought into contact with an organic substance to modify the organic substance to reduce its molecular weight.

[2] The method for reducing the molecular weight of organic substances according to the above [1], wherein the exhaust gas (g ₀ ) is obtained by separating at least a part of nitrogen from the exhaust gas containing carbon monoxide and nitrogen generated in a metallurgical furnace to increase the concentration of carbon monoxide exhaust gas.

[3] The method for reducing the molecular weight of an organic substance according to [1] or [2] above, wherein the water vapor concentration of the mixed gas (g) is 5 to 70% by volume.

[4] The method for reducing the molecular weight of an organic substance as described in [3] above, wherein the water vapor concentration in the mixed gas (g) is 20 to 70% by volume, the hydrogen concentration is 10 to 40% by volume, and the carbon dioxide concentration is 10 to 40% by volume. 40% by volume.

[5] The method for reducing the molecular weight of an organic substance according to any one of [1] to [4] above, wherein the organic substance to be modified is one or more selected from waste plastics, oily sludge, and waste oil .

[6] A method for producing a fuel, the method comprising: using a gaseous fuel and a modified product of an organic substance obtained by the method for reducing the molecular weight of an organic substance according to any one of [1] to [5] above. and/or recovery in the form of liquid fuel.

[7] A method for utilizing waste gas produced by a metallurgical furnace, the method comprising: having a gas storage tank temporarily storing waste gas (g ₀ ) containing carbon monoxide intermittently generated from a metallurgical furnace, storing the gas stored in the gas storage tank The exhaust gas (g ₀ ) is sent to the air supply pipe of the gas utilization equipment and the exhaust gas equipment of the exhaust gas combustion flue for diffusion combustion of the exhaust gas (g ₀ ) that cannot be stored in the gas receiver, and the air supply branched from the above air supply pipe A part of the exhaust gas (g ₀ ) is discharged from the pipe, and excess water vapor is added to the exhaust gas (g ₀ ) to cause the shift reaction to form hydrogen and carbon dioxide produced by the shift reaction and water vapor not consumed in the shift reaction. The mixed gas (g) is brought into contact with an organic substance to modify the organic substance to reduce its molecular weight.

[8] The method described in [7] above, wherein the waste gas (g ₀ ) to which an excess amount of water vapor is added to undergo a shift reaction is obtained by separating at least a part of nitrogen from a waste gas containing carbon monoxide and nitrogen generated from a metallurgical furnace. Exhaust gas with elevated carbon monoxide concentration.

[9] The method according to [7] or [8] above, wherein the water vapor concentration of the mixed gas (g) is 5 to 70% by volume.

[10] The method according to [9] above, wherein the water vapor concentration in the mixed gas (g) is 20 to 70% by volume, the hydrogen concentration is 10 to 40% by volume, and the carbon dioxide concentration is 10 to 40% by volume.

[11] The method according to any one of [7] to [10] above, wherein the organic substance to be modified is one or more selected from waste plastics, oily sludge, and waste oil.

[12] A method for producing a fuel, the method comprising: converting the modified organic substance obtained by the method described in any one of [7] to [11] above in the form of gaseous fuel and/or liquid fuel Recycle.

The effect of the invention

According to the first invention of the present application, when reducing the molecular weight of high molecular weight organic substances such as waste plastics and converting them into gaseous fuels, liquid fuels, etc., it is possible to efficiently modify the organic substances using a gas that can be supplied stably to achieve low molecular weight. Obtain heavy components or high-calorie modified products with less carbon and a large amount of light components. In addition, as for the implementation equipment, no special meter or flow path switching valve is required, and the modification of the organic substance can be performed even at a relatively low reaction temperature, so it can be implemented with relatively simple equipment. In addition, since _CO2 generated by the shift reaction is converted into CO by a carbon dioxide reforming reaction in the modification of organic substances, chemical reuse of organic substances can be carried out without increasing the amount of _CO2 generated.

In addition, according to the second invention of the present application, waste gas from a metallurgical furnace containing carbon monoxide, which is a relatively low-calorie waste gas, can be used as a raw material for a specific process of reducing the molecular weight of organic substances such as waste plastics and converting them into gaseous fuels, liquid fuels, etc. Gas is used efficiently. Gaseous fuels and liquid fuels are indispensable in metal smelting facilities such as ironworks, and are fuels that are consumed stably, so there is no need to reduce the amount of production as needed, so the waste gas generated by metallurgical furnaces can be used as raw material gas in a stable manner It can be used (consumed) efficiently, thereby stably reducing the amount of combustion emission of waste gas produced by metallurgical furnaces. Especially in metal smelting equipment such as ironworks, the amount of waste gas generated by metallurgical furnaces is proportional to the fuel consumption and production in the equipment, so the amount of waste gas generated by metallurgical furnaces is proportional to the amount of waste gas used for fuel manufacturing. The amount of waste gas produced by the metallurgical furnace is also proportional to the amount used. Considering this aspect, the combustion emission of the waste gas produced by the metallurgical furnace can also be stably reduced.

In addition, from the perspective of the treatment of organic substances such as waste plastics, when converting high-molecular-weight organic substances such as waste plastics to low molecular weight and converting them into gaseous fuels, liquid fuels, etc., it is effective to use the exhaust gas generated by the metallurgical furnace that can be supplied stably. Low molecular weight is achieved by modifying organic substances to obtain high-calorie modified products with less heavy components and carbonaceous components and a large amount of light components. In addition, as for the implementation equipment, no special meter or flow path switching valve is required, and the modification of the organic substance can be performed even at a relatively low reaction temperature, so it can be implemented with relatively simple equipment. In addition, _CO2 generated by the shift reaction is changed to CO in the carbon dioxide reforming reaction at the time of modification of organic substances, so chemical reuse of organic substances can be carried out without increasing the amount of _CO2 generated.

Description of drawings

[Fig. 1] is a graph showing the relationship between the amount of water vapor added in the shift reaction by adding water vapor to the converter gas and the gas composition after the shift reaction (calculated value of the equilibrium composition at a temperature of 430°C) picture;

[ Fig. 2 ] is a structural diagram showing an exhaust gas facility of a converter in a conventional general ironworks;

[ FIG. 3 ] is a block diagram showing one embodiment of an apparatus for carrying out the present invention;

[ Fig. 4 ] is a graph showing the relationship between the water vapor concentration of the shift reaction gas in Example 1 and the gasification rate and liquefaction rate in modification (lower molecular weight) of polyethylene;

[ Fig. 5 ] is a graph showing the relationship between the water vapor concentration of the gas generated by the shift reaction and the LHV of the gaseous fuel and the liquid fuel obtained by modifying (low molecular weight) polyethylene in Example 1;

[ Fig. 6 ] is a graph showing the relationship between the water vapor concentration of the shift reaction gas in Example 1 and the polyethylene decomposition rate in the modification (lower molecular weight) of polyethylene;

[ Fig. 7 ] is a graph showing the relationship between the carbon dioxide concentration of the gas generated by the shift reaction in Example 1 and the hydrogen concentration of the gaseous fuel obtained by modification (molecular weight reduction) of polyethylene;

[ Fig. 8 ] is a graph showing the relationship between the hydrogen concentration of the gas generated by the shift reaction in Example 1 and the carbon dioxide concentration of the gaseous fuel obtained by modification (molecularization) of polyethylene;

[ FIG. 9 ] is an explanatory diagram schematically showing the equipment used in Embodiment 1 (Invention Example 11);

[ Fig. 10 ] is a graph showing the transition of the gas storage tank level and combustion emission in a conventional example;

[ Fig. 11 ] is a graph showing the transition of the gas storage tank level and combustion emission in the inventive example of Example 2;

[ Fig. 12 ] is a graph showing the cumulative combustion emissions of the conventional example and the example of the present invention obtained from Figs. 10 and 11 .

Symbol Description

1 Converter

2 Gas recovery equipment

3 three-way valve

4 Exhaust gas combustion flue

5 gas storage tank

6 air supply pipe

7 Gas Utilization Equipment

8 Transform Reactor

9 Modification Reactor

10 liquid fuel trap

11 Gas cooler

60 air supply pipe

90 gas dispersion plate

A processing equipment

a Polyethylene

b net

c Ni catalyst

Detailed ways

First, the method for reducing the molecular weight of an organic substance according to the first invention of the present application will be described.

In the method of the present invention, excess water vapor is added to exhaust gas (g ₀ ) containing carbon monoxide (hereinafter, sometimes referred to as "exhaust gas from metallurgical furnace") produced by a metallurgical furnace to undergo a shift reaction to form hydrogen and A mixed gas (g) of carbon dioxide and water vapor not consumed in the shift reaction is brought into contact with an organic substance to modify the organic substance at a low molecule. It should be noted that adding excess water vapor to the exhaust gas (g ₀ ) means adding water vapor so that excess water vapor not consumed in the shift reaction remains in the mixed gas (g).

In such a method of the present invention, even at a relatively low reaction temperature, the molecular weight reduction of organic substances can be effectively promoted, the amount of hydrogen consumption is small, and the generation of heavy components and carbonaceous substances is hardly confirmed.

It is known that high-molecular-weight organic substances such as waste plastics usually start to thermally decompose when heated above 300-400° C., and at this time, weight reduction and weight reduction also proceed. When hydrogen is allowed to coexist during thermal decomposition, the hydrogenation reaction and the hydrocracking reaction to hydrocarbon species proceed, and therefore, it is effective for suppressing heaviness and molecular weight reduction. However, hydrocracking requires high temperature, and there is a problem that hydrogen consumption increases.

On the other hand, steam reforming and carbon dioxide reforming can be regarded as the oxidation of hydrocarbons caused by oxygen in H ₂ O and CO ₂ molecules, and can achieve low molecular weight and suppress carbonaceous generation with a small amount of hydrogen addition. Furthermore, steam reforming and carbon dioxide reforming have a characteristic that the reaction temperature decreases as the carbon chain of the organic molecule to be modified grows. In the method of the present invention, even at a relatively low reaction temperature, the low molecular weight of the organic substance can be effectively promoted, the amount of hydrogen consumption is small, and the generation of heavy components and carbonaceous substances is hardly confirmed. Four reactions of hydrogenation, hydrocracking, steam reforming, and carbon dioxide reforming proceed simultaneously by modifying (reducing the molecular weight) of the organic substance using the above-mentioned mixed gas (g).

For example, exhaust gas generated from metallurgical furnaces such as converters usually contains about 25 to 80% by volume of CO. Therefore, when water vapor is added thereto, H ₂ and CO ₂ are generated by the following shift reaction (1).

CO＋ _H2O → _H2 ＋ _CO2 …(1)

In the method of the present invention, since excess water vapor is added to the waste gas (g ₀ ), the mixed gas (g) after the shift reaction contains H ₂ , CO ₂ and excess added H ₂ O. Furthermore, it is considered that in the modification (lower molecular weight) of the organic substance by the gas (g) produced by the shift reaction, the four steps of hydrogenation, hydrocracking, steam reforming, and carbon dioxide reforming of each gas component are simultaneously carried out. reaction.

In the present invention, the concentrations of water vapor, hydrogen, and carbon dioxide in the gas can be controlled by appropriately controlling the excess proportion of water vapor added to the exhaust gas (g ₀ ) and the reaction rate of the shift reaction, thereby forming organic matter modified Sexual use of mixed gas (g). However, because the composition of the exhaust gas from metallurgical furnaces stored in gas storage tanks (for example, common gas storage tanks used in ironworks) is generally CO: 50 to 70% by volume, CO ₂ : 10 to 20% by volume %, N ₂ : 10-20% by volume, H ₂ : 0-5% by volume (in addition to containing saturated water vapor), therefore, it is generally not necessary to control the reaction rate of the shift reaction, and it can be adjusted only by adjusting the excess ratio of water vapor The respective concentrations of water vapor, hydrogen, and carbon dioxide in the mixed gas (g) are controlled to desired levels.

It should be noted that the reaction rate of the shift reaction can be controlled by adjusting the residence time in the shift reactor. For example, in order to shorten the residence time, the method of reducing the length of the shift reactor or the filling amount of the catalyst is usually adopted. In this case, the length of the shift reactor and the filling amount of the catalyst can be set to 1/2 of the time when the reaction progresses to a basic equilibrium ~1/4 or so.

As an example _, for _a converter _gas of ₁₀₀ kmol/h ( = 2240Nm ³ /h) by changing the amount of water vapor added from 60kmol/h (= 1340Nm ³ /h) to 540kmol/h (= 12100Nm ³ /h) to perform a shift reaction. Figure 1 shows the amount of water vapor added Gas composition after reaction with shift (calculated value of equilibrium composition at a temperature of 430°C). From this, it can be seen that the respective concentrations of water vapor, hydrogen, and carbon dioxide in the mixed gas (g) can be controlled by only adjusting the amount of water vapor added, and a preferable gas composition as described later can be obtained. In addition, it can be seen that the transformation reaction usually proceeds until the reaction reaches a basic equilibrium.

Next, details and preferable conditions of the method of the present invention will be described.

In the present invention, the reason for using waste gas from a metallurgical furnace as the waste gas (g ₀ ) for the shift reaction is as follows: the waste gas from the metallurgical furnace contains carbon monoxide at a relatively high concentration and has a low concentration of unnecessary nitrogen. Any waste gas can be used as the waste gas (g ₀ ) generated from a metallurgical furnace containing carbon monoxide. The most representative one is the converter gas generated from the converter that performs the decarburization process of the iron and steel manufacturing process. Other examples include exhaust gas generated from the iron pretreatment furnace, smelting reduction furnace, shaft furnace, etc., and can be used One or a mixture of two or more of these exhaust gases.

The ratio of carbon monoxide generated in the metallurgical process to further oxidize to generate carbon dioxide, that is, the secondary combustion rate (CO ₂ /(CO+CO ₂ )×100), is usually only about 10 to 50%. In addition, hydrogen and nitrogen are also contained in the exhaust gas (g ₀ ), and the concentration of H ₂ varies depending on the metallurgical process, and is about 0 to 20% by volume. Nitrogen is supplied for stirring in the furnace, flue protection, etc., and its concentration in the exhaust gas (g ₀ ) is usually about 10 to 30% by volume.

From the above points, the composition of the exhaust gas (g ₀ ) generated from a general metallurgical furnace is approximately in the following range.

CO: 80-25% by volume (equivalent to a secondary combustion rate of 10-50%)

CO ₂ : 10-25% by volume (equivalent to a secondary combustion rate of 10-50%)

N ₂ : 10-30% by volume

H ₂ : 0-20% by volume

Carbon monoxide is required for the shift reaction, and there is no particular problem with the composition of the exhaust gas (g ₀ ) as long as the composition of the gas is within the above range. Here, nitrogen does not bring any contribution to the chemical reactions (shift reaction, hydrogenation, hydrocracking, water vapor reforming, carbon dioxide reforming) that occur in the present invention. The heat of combustion (hereinafter, referred to as "LHV") decreases. In particular, when the nitrogen concentration exceeds 50% by volume, the LHV of the gaseous fuel decreases significantly, and the shift reaction rate also tends to decrease. Therefore, the nitrogen concentration is preferably within the above composition range.

As mentioned above, the composition of the waste gas generated from the metallurgical furnace stored in the gas storage tank (for example, a general gas storage tank used in ironworks) is generally CO: 50-70% by volume, CO ₂ : 10-20 % by volume, N ₂ : 10 to 20% by volume, H ₂ : 0 to 5% by volume (in addition, including saturated water vapor), this composition corresponds to a high CO concentration composition in the composition of the exhaust gas generated by the above-mentioned general metallurgical furnace . Since the gas stored in the gas storage tank is used as fuel gas at each plant in the ironworks, it is necessary to prevent a decrease in combustion efficiency at the place of use. Therefore, the reason why the lower limit value of the CO concentration in gas is set as the storage condition in the gas tank is because a high CO concentration composition is formed.

In the present invention, regardless of the composition of the waste gas with higher CO concentration stored in the usual gas storage tank used in the ironworks or the waste gas produced by the above-mentioned common metallurgical furnace, it can be used as the waste gas ( g ₀ ) to be utilized.

However, in the waste gas (g ₀ ) generated from a metallurgical furnace, there is a gas with a low carbon monoxide concentration and a high nitrogen concentration such as blast furnace gas, and the waste gas (g ₀ ) generated from such a metallurgical furnace can contain After at least a part of the nitrogen is separated (removed) to increase the carbon monoxide concentration, an excess of water vapor is added to carry out the shift reaction. In addition, since the nitrogen concentration in the exhaust gas depends on the requirements for the heat of combustion of the gaseous fuel generated in the low molecular weight of the organic matter, it cannot be uniformly determined. However, if the nitrogen concentration in the exhaust gas exceeds 30% by volume, it is preferable to install nitrogen separation. The process serves to separate (remove) at least a portion of the nitrogen from the off-gas (g ₀ ).

Typical examples of offgas that are preferably subjected to nitrogen separation include blast furnace gas, and other examples include offgas from electric furnaces and shaft furnaces that operate under conditions where the nitrogen concentration is high. In addition, it is also possible to perform nitrogen separation on exhaust gas containing relatively high concentration of carbon monoxide such as converter gas, and to further increase the concentration of carbon monoxide before performing the shift reaction.

The method for separating nitrogen from exhaust gas is not particularly limited, and any method such as adsorption separation method or distillation separation method can be used, but adsorption separation method is particularly preferable because the boiling point difference between nitrogen and carbon monoxide is small. For example, since activated carbon loaded with Cu ⁺ known as a CO adsorbent also adsorbs CO ₂ , it can be obtained from blast furnace gas ⁽ approximate composition: N ₂ : 50 vol. %, CO: 25% by volume, CO ₂ : 25% by volume) to obtain as desorption gas roughly composed of N ₂ : 15% by volume, CO: 45% by volume, and CO ₂ : 40% by volume. The nitrogen in the gas is separated and the carbon monoxide is concentrated.

The conversion reaction in the method of the present invention is not particularly limited, and known methods can be used. In general, steam is added in advance to waste gas (g ₀ ) generated in a metallurgical furnace, and this is introduced into a fixed-bed reactor filled with a catalyst to perform a shift reaction. In addition, part of the water vapor can also be added in advance, and the catalyst can be added to the reactor through multiple stages, and then the remaining water vapor can be added from between the catalyst layer and the catalyst layer.

In addition, if water vapor, hydrogen, and carbon dioxide are added to the waste gas (g ₀ ) produced by the metallurgical furnace, respectively, without performing the shift reaction as in the present invention, it is also possible to obtain the organic substance modified in the shift reaction of the present invention. Gases of the same composition as the mixed gas (g) are used, but in such a method, expensive hydrogen and carbon dioxide must be added in addition to water vapor, and the cost increases.

In the present invention, the mixed gas (g) for modifying organic substances obtained by the shift reaction contains water vapor, hydrogen, and carbon dioxide, and their concentrations are not particularly limited, but the water vapor concentration is preferably 5 to 70 volumes for the following reasons. %. That is, if the water vapor concentration is low, the decomposition rate of organic substances such as waste plastics decreases, and by setting the water vapor concentration to 5% by volume or more, a certain level of decomposition rate of organic substances can be ensured, and the production rate of gaseous fuel ( Vaporization rate) and liquid fuel production rate (liquefaction rate) are at a certain level, and the production amount of heavy components can be reduced. On the other hand, if the water vapor concentration is high, CO ₂ tends to remain in the gas generated by the modification reaction of organic substances (the gas generated by the modification and low molecular weight of organic substances, the same below), and the gaseous fuel and liquid fuel The LHV tends to decrease, and if the water vapor concentration is 70% by volume or less, it is possible to suppress the remaining CO ₂ in the gas generated by the reforming reaction, and it is also possible to suppress the decrease in the LHV of gaseous fuels and liquid fuels.

In addition, from the viewpoint of securing the decomposition rate of organic substances, both the hydrogen concentration and the carbon dioxide concentration in the mixed gas (g) are preferably 5% by volume or more.

In addition, the more preferable composition of the mixed gas (g) for modifying organic substances is water vapor concentration: 20 to 70% by volume, hydrogen concentration: 10 to 40% by volume, and carbon dioxide concentration: 10 to 40% by volume for the following reasons . In addition, other gas components (for example, nitrogen, etc.) may be contained in this mixed gas (g). By setting the water vapor concentration to 20% by volume or more, the decomposition rate of organic substances can be sufficiently increased, and the LHV of the gaseous fuel can be increased. The reason for setting the water vapor concentration to 70% by volume or less is as described above. By setting the hydrogen concentration to 10% by volume or more (more preferably 12% by volume or more), CO ₂ remaining in the gaseous fuel can be suppressed especially when the modification reaction of the organic substance is performed at a relatively low temperature. By setting the carbon dioxide concentration to 10% by volume or more (more preferably 13% by volume or more), it becomes difficult for gas component H ₂ , which has a lower calorific value than hydrocarbons and CO, to remain in the gaseous fuel. In addition, by setting the hydrogen concentration and the carbon dioxide concentration to 40% by volume or less, the decomposition rate of organic substances such as waste plastics can be made to a preferable level. In addition, from the above point of view, a more preferable gas composition of the mixed gas (g) is water vapor concentration: 25 to 65% by volume, hydrogen concentration: 15 to 35% by volume, and carbon dioxide concentration: 15 to 35% by volume. In addition, other gas components (for example, nitrogen, etc.) may be contained in this mixed gas (g).

In addition, as one of the characteristics of the present invention, it is possible to control the ratio of the gaseous fuel generation amount and the liquid fuel generation amount in the modification of organic matter by the water vapor concentration of the mixed gas (g) for organic matter modification. That is, if the water vapor concentration of the mixed gas (g) is set to 50% by volume or more, gaseous fuel is mainly produced (that is, the amount of gaseous fuel produced > the amount of liquid fuel produced), and if the water vapor concentration is set to 40% by volume Hereinafter, liquid fuel is mainly generated (that is, gaseous fuel generation<liquid fuel generation). It should be noted that the influence of hydrogen concentration and carbon dioxide concentration is not so significant as the influence of water vapor concentration, so it only needs to be within the preferred range of the present invention.

Next, conditions for modifying (reducing molecular weight) of organic substances using the mixed gas (g) obtained by the shift reaction will be described.

In the present invention, there are no particular limitations on the organic substance to be reduced in molecular weight by modification, but a high molecular weight organic substance is preferred, for example, waste plastics, oily sludge, waste oil, etc. can be used as one of them More than one species is the object.

Here, the oily sludge refers to a sludge-like mixture generated in the oily waste liquid treatment process, and generally contains about 30 to 70% by mass of water. Examples of the oil in sludge include, but are not limited to, various mineral oils, natural and/or synthetic oils and fats, various fatty acid esters, and the like. In addition, in order to improve the operability when supplying oil-containing sludge to the reforming reactor (reactor for modifying organic matter to reduce its molecular weight, the same below), it is also possible to use methods such as centrifugation to make the oil in the sludge The water content is reduced to about 30 to 50% by mass.

In addition, examples of waste oil include, but are not limited to, various mineral oils used, natural and/or synthetic oils and fats, various fatty acid esters, and the like. In addition, it may be a mixture of two or more of the above waste oils. In addition, waste oil produced in the rolling process of ironworks generally contains a large amount (usually more than about 80% by mass) of water, and from the viewpoint of workability, the water is reduced in advance by methods such as specific gravity separation. is advantageous.

When the organic substance contains water, since water vapor is generated in the reforming reactor, the excess ratio of water vapor added in the shift reaction is determined in consideration of this part of water vapor.

In addition, if waste plastics contain chlorine-containing resins such as polyvinyl chloride, chlorine gas will be generated in the modification reactor, and this chlorine gas may be contained in gaseous fuels and liquid fuels. Therefore, when waste plastics may contain chlorine-containing resins, it is preferable to put a chlorine absorbent such as CaO into the reforming reactor so that the generated gas fuel and liquid fuel do not contain chlorine components.

The reaction temperature at the time of modifying the organic substance is preferably set as follows according to the type of the organic substance. In the case of waste plastics, the reaction temperature is about 400-900°C. When the reaction temperature is lower than 400° C., the decomposition rate of waste plastics is low. On the other hand, when the reaction temperature exceeds 900° C., carbonaceous generation increases. In addition, in the case of oily sludge or waste oil, the reaction temperature is preferably about 300 to 800°C. When the reaction temperature is lower than 300°C, the decomposition rate of oily sludge or waste oil decreases. On the other hand, if the reaction temperature exceeds 800° C., it does not affect the modification (molecular weight reduction) properties of oily sludge or waste oil, but it is uneconomical because it is a higher temperature than necessary. In addition, in the case of a mixture of waste plastics and oily sludge and/or waste oil, the reaction temperature is preferably about 400 to 800° C. from the above viewpoint. In addition, the reaction temperature has substantially no effect on the ratio of gaseous fuel generation to liquid fuel generation. In addition, since the influence of pressure was basically not confirmed, it is economical to operate the reforming reactor at normal pressure or slightly pressurized on the order of several kg/cm ² .

The type of modification reactor is not particularly limited, considering that organic substances such as waste plastics move smoothly in the reactor, and can be effectively contacted with the mixed gas (g) for organic substance modification, a horizontal type such as a rotary kiln is preferred. Moving bed reactor.

In addition, in the present invention, a catalyst is not particularly required for the modification of an organic substance, but a catalyst may be filled and the reaction may be performed. As the catalyst, one or two or more catalysts each having steam reforming activity, carbon dioxide reforming activity, hydrogenation activity, and hydrocracking activity can be used. Specific examples include Ni-based reforming catalysts, Ni-based hydrogenation catalysts, Pt/zeolite-based petroleum refining catalysts, and the like. In addition, it is known that dust generated from a converter containing fine Fe particles can also be used as a reforming catalyst or a hydrocracking catalyst.

In the case of filling the catalyst, a vertical reforming reactor can be used instead of a horizontal moving bed reforming reactor such as a rotary kiln in view of good contact between waste plastics and other organic substances and the catalyst. In this case, the mixed gas (g) obtained in the shift reaction is a moving bed reforming reactor. In this case, when the mixed gas (g) obtained in the shift reaction is supplied from the lower part and/or the side part compared with the case where the mixed gas (g) obtained in the shift reaction is supplied from the upper part of the reforming reactor, The contact between the mixed gas (g) and the organic substance or the catalyst is better, so it is preferable.

As a vertical reforming reactor, a common fixed-bed reactor used in the chemical industry can be used, especially when the mixed gas (g) is supplied from the lower part of the reforming reactor, it can be used as a refining reactor. Blast furnaces, shaft furnaces, or converters of iron equipment are used as reforming reactors. In the case of using a blast furnace or a shaft furnace as a reforming reactor, it is preferable that the reaction efficiency is increased if it is made into a moving bed type in which organic substances are continuously supplied from the upper part of the furnace. The catalyst and the mixed gas (g) are supplied from the lower part of the furnace to make them convectively contact, and the gaseous product is continuously extracted from the upper part of the furnace, and the liquid product and the catalyst are drawn out from the lower part of the furnace. In addition, when the converter is used as a reforming reactor, it can be made into the same batch reaction form as blowing, that is, after the organic matter and catalyst are put into the furnace, the mixed gas is continuously supplied from the lower part of the furnace. (g) The gaseous product is continuously extracted from the upper part of the furnace, and the liquid product and the catalyst are reacted for a certain period of time, and the furnace is tilted to be extracted.

The modified organic substances obtained by the method of the present invention are usually gases and liquids, which are suitable as gas fuels and liquid fuels.

Combustible components in gaseous fuels are composed of carbon monoxide and C1-C4 hydrocarbons, and their LHV is about 6-10 Mcal/Nm ³ . As such, it has a feature that although its LHV is equivalent to natural gas, its combustibility is higher than that of natural gas due to its high concentration of carbon monoxide. Since the carbon monoxide concentration is high and combustibility is high, it is more preferable to use it as an alternative city gas fuel in a factory having a metallurgical furnace such as an ironworks than as a domestic city gas supply from the viewpoint of safety.

Liquid fuel is composed of C5-C24 hydrocarbons, so it is a mixture of naphtha (C5-C8), kerosene (C9-C12), and light oil (C13-C24), and basically does not contain heavy oil (above C25) Excellent light oil. The liquid fuel can also be separated by distillation to make naphtha, kerosene, and light oil, but it can also be used in the form of a mixture as a fuel for factories with metallurgical furnaces such as ironworks, or as a substitute for heavy oil in smelting furnaces. agent use.

In addition, since naphtha (C5-C8) has a large content, it can be used not only as a light liquid fuel, but also as a chemical industrial raw material after distilling and separating the naphtha components. In this regard, a utilization method of converting the distilled naphtha component into benzene, toluene, xylene, etc. by catalytic modification is mentioned.

The modified product of organic matter obtained by the method of the present invention can be separated into gas fuel and liquid fuel by gas-liquid separation after cooling the gas generated by the modification reaction. In addition, naphtha, kerosene, and light oil can be separated from liquid fuels by distillation separation as required. Known methods can be used for the cooling method, gas-liquid separation method, and distillation separation method of the gas generated by the modification reaction, and are not particularly limited.

In addition, from the above point of view, if a mixed gas having the same composition as the mixed gas (g) obtained in the present invention is used, it is possible to effectively decompose and lower the molecular weight of the organic substance. In particular, by using water vapor concentration: 20 to 70% by volume, hydrogen concentration: 10 to 40% by volume, carbon dioxide concentration: 10 to 40% by volume, more preferably water vapor concentration: 25 to 65% by volume, hydrogen concentration: 15 to 35% by volume, carbon dioxide concentration: 15 to 35% by volume of the mixed gas can sufficiently increase the decomposition rate of organic matter, and can increase the LHV of the gaseous fuel. It should be noted that the mixed gas may also contain other gas components (such as nitrogen, etc.).

The reason for limiting such a gas composition is the same as the reason for limiting the method of the present invention described above. In order to obtain the mixed gas of the above composition by methods other than the method of the present invention, for example, one or more of water vapor, hydrogen, and carbon dioxide needs to be added to the base gas.

The conditions for the modification (molecular reduction) of the organic substance by this mixed gas are the same as the conditions for the modification (lower molecular weight) of the method of the present invention described above.

Therefore, the gist of this method is the following [i] to [iv], and "Example 1" of the present invention described later is also an example of the method of the following [i] to [iv].

[i] A method for reducing the molecular weight of an organic substance, characterized in that a mixed gas having a water vapor concentration of 20 to 70% by volume, a hydrogen concentration of 10 to 40% by volume, and a carbon dioxide concentration of 10 to 40% by volume is mixed with an organic substance. Substances are contacted to modify organic substances to reduce their molecular weight.

[ii] A method for reducing the molecular weight of an organic substance, wherein, in the method of [i] above, the water vapor concentration of the mixed gas is 25 to 65% by volume, the hydrogen concentration is 15 to 35% by volume, and the carbon dioxide concentration is 15 to 35% by volume.

[iii] A method for reducing the molecular weight of organic substances, characterized in that, in the above method [i] or [ii], the organic substance to be modified is one selected from waste plastics, oily sludge, and waste oil more than one species.

[iv] A method for producing a fuel, characterized in that the modified organic substance obtained by any one of the above methods [i] to [iii] is recovered as a gaseous fuel and/or a liquid fuel.

Next, the utilization method of the waste gas produced|generated in the metallurgical furnace of the 2nd invention of this application is demonstrated.

Various metallurgical furnaces for intermittent production, such as converters, intermittently produce a large amount of waste gas during production. For example, a converter generates exhaust gas with a CO concentration of about 30 to 70% by volume at an instantaneous flow rate of about 100,000 to 300,000 Nm ³ /hr. However, since the blowing time is about 10 to 30 minutes, the time-average flow rate including the time without blowing is only 17,000 to 50,000 Nm ³ /hr (the instantaneous flow rate is 100,000 Nm ³ /hr In the case of ), there is a big difference with the instantaneous flow. Since the low-level combustion heat of converter gas is about 1800 to 2000 kcal/Nm ³ , it can be effectively used as fuel in ironworks, etc. However, since it is generated intermittently, the exhaust gas must be used at a flow rate lower than the previous time-average flow rate, and it is substantially out of balance with the instantaneous flow rate. Therefore, there is a problem that there is a time when it cannot be completely stored in the gas receiver, and it is necessary to carry out diffusion combustion from the exhaust gas combustion flue.

Fig. 2 shows an exhaust gas installation of a converter in a general ironworks. The gas discharged from the converter 1 is recovered by the gas recovery device 2, and the gas storage tank 5 (for example, a gas storage tank with a movable piston inside and a variable capacity such as a Wiggins type gas storage tank) As a buffer, gas is sent to each gas utilization facility 7 in the ironworks through the gas supply pipe 6 . At this time, because of the large difference between the above-mentioned time average flow rate and instantaneous flow rate, the situation that it cannot be completely accommodated in the air storage tank 5 occurs. Therefore, the three-way valve 3 is switched to the exhaust gas combustion flue 4 side, and the exhaust gas is carried out. Diffusion burning. In particular, when the blowing of another converter (not shown) overlaps, since a very large instantaneous flow rate is formed, diffusion combustion cannot be avoided.

In order to reduce combustion emissions, it is effective to increase the utilization of exhaust gas in ironworks as described above, but it is difficult to use exhaust gas at a high level especially in domestic ironworks, and it is difficult to simply increase the utilization amount.

However, high-calorie fuels such as natural gas and petroleum are used as auxiliary fuels or auxiliary carbon materials for blowing into blast furnaces and increasing the heat of fuel gas for in-house power plants that use ironmaking waste gas as fuel. Therefore, if the exhaust gas can be converted into a high-calorie fuel, the utilization amount of the exhaust gas can be increased netly, and as a result, the combustion emission amount can be reduced.

Therefore, in the present invention, in the gas recovery facility, a part of the exhaust gas (g ₀ ) is discharged through the air supply pipe branched from the above-mentioned air supply pipe, and converted into a gas by lowering the molecular weight of organic substances such as waste plastics. The raw material gas of the above-mentioned specific process (the low molecular weight method of the first invention of the present application) such as fuel, liquid fuel, etc. is used, and the gas recovery equipment has: temporarily storing the above-mentioned intermittent A storage tank for the generated exhaust gas (g ₀ ) containing carbon monoxide (hereinafter, sometimes referred to as "exhaust gas from metallurgical furnaces"), and a gas supply pipe for transporting the exhaust gas (g ₀ ) stored in the storage tank to gas utilization equipment , Exhaust gas combustion flue for diffusion combustion of exhaust gas (g0) that cannot be stored in the gas storage tank. That is, by adding excess water vapor to the exhaust gas (g ₀ ) and causing the shift reaction to form a mixed gas (g) containing hydrogen and carbon dioxide generated by the shift reaction and water vapor not consumed in the shift reaction, the The mixed gas (g) contacts with the organic substance, and the organic substance is modified and reduced in molecular weight.

In this way, the present invention uses waste gas generated from metallurgical furnaces as a raw material gas for a specific process of reducing the molecular weight of organic substances such as waste plastics and converting them into gaseous fuels, liquid fuels, and the like. Gaseous fuels and liquid fuels are indispensable in metal smelting facilities such as ironworks, and they are consumed stably, so there is no need to reduce their production volume as needed, so the waste gas generated from metallurgical furnaces can be stably used as raw material gas Use (consumption), thereby, can also stably reduce the amount of combustion emission of waste gas generated by metallurgical furnaces.

It should be noted that the characteristics and advantages of the molecular reduction treatment of organic substances performed in the present invention are as described above in the method for reducing molecular weight of organic substances according to the first invention of the present application.

Fig. 3 is a configuration diagram of an embodiment of an apparatus for carrying out the present invention, showing a case where the waste gas generated from a metallurgical furnace is a converter gas. In the figure, A is a processing facility that uses waste gas (g ₀ ) as a raw material gas to reduce the molecular weight of organic substances and convert them into gaseous fuels and liquid fuels. 8 is a shift reactor constituting this processing facility A, and 9 The same is the modified reactor.

Similar to Fig. 2, the exhaust gas (g ₀ ) discharged from the converter 1 is recovered by the gas recovery equipment 2, and the gas storage tank 5 is used as a buffer, and the gas is sent to each gas utilization equipment 7 in the ironworks through the gas supply pipe 6, and passed through A required amount of waste gas (g ₀ ) is discharged from an air supply pipe 60 branched in the middle of the air supply pipe 6, and is sent to the processing facility A as a raw material gas for reducing the molecular weight of organic substances and converting them into gaseous fuels/liquid fuels.

In the treatment facility A, after mixing steam into the exhaust gas (g ₀ ) (as will be described later, part of the mixing of the steam may be performed in the shift reactor 8), it is introduced into the shift reactor 8 for shifting. reaction, and then the mixed gas (g) after the shift reaction (shift reaction product gas) is introduced into the modification reactor 9 to modify (lower molecular weight) the organic substance.

In addition, the details and preferable conditions of the low-molecular-weight treatment of organic substances in the method of the present invention are as described above in the method for low-molecular weight organic substances of the first invention of the present application. Therefore, the concentration of carbon monoxide can be increased by separating (removing) at least part of the nitrogen contained in the waste gas (g ₀ ) generated from the metallurgical furnace, and then an excess of water vapor can be added to perform a shift reaction.

Like blast furnace gas, even if it is a waste gas containing carbon monoxide that is continuously generated from a metallurgical furnace rather than intermittently, as explained in detail in the first invention of the present application, organic substances such as waste plastics can be efficiently converted into Gas fuel, liquid fuel. Even if the waste gas produced by the continuous metallurgical furnace has a waste gas combustion flue in the waste gas system, the amount of combustion emissions can be reduced due to the same effect as the second invention of the present application.

On the other hand, in the case of exhaust gas from a continuously produced metallurgical furnace without an exhaust gas combustion flue in the exhaust system, there is no effect of directly reducing combustion emissions. However, the gaseous fuel and liquid fuel produced by the method of the present invention are fuels that can be stably consumed in metal smelting facilities such as ironworks, and are characterized by higher combustion heat than blast furnace gas and the like. As a result, the energy efficiency of the metal smelting facility as a whole is improved, and as a result, the amount of external fuels such as natural gas and heavy oil is reduced, which is equivalent to the reduction of combustion emissions.

Example

[Example 1]

· Invention Example 1

A branch pipe is provided on the gas discharge pipe of the gas storage tank that temporarily stores the converter gas, and a part of the converter gas can be discharged through the branch pipe. On the downstream side of the branch pipe, a flow regulating valve, a steam mixer, a preheater (for a mixture of converter gas and steam), a shift reactor (cylindrical vertical), a reforming reactor (external heating type) are arranged in sequence. Converter), a gas cooler for cooling reforming reaction product gas equipped with a liquid fuel trap. A quantitative feeding device for waste plastics in the form of a spiral conveyor belt is arranged on the feeding side of the above-mentioned modification reactor. In addition, a sampling port and a flow meter were installed in the discharge-side piping of the shift reactor and the discharge-side piping of the cooled gas of the gas cooler.

The average composition of the converter gas in the gas storage tank was H ₂ : 12% by volume, CO: 54% by volume, CO ₂ : 17% by volume, H ₂ O: 1% by volume, and N ₂ : 16% by volume. The converter gas was supplied to the steam mixer at 74 Nm ³ /h, steam at a pressure of 10 kg/cm ² G was supplied as water vapor at 100 Nm ³ /h, the temperature was raised to 320° C. by the preheater, and then introduced into the shift reactor ( Filled with Fe-Cr high temperature conversion catalyst). Through the shift reaction in the shift reactor, a gas composition of H ₂ : 26% by volume, CO: 2% by volume, CO ₂ : 28% by volume, H ₂ O: 37% by volume, and N ₂ : 7% by volume was obtained. Gas (shift reaction produces gas). The flow rate of the gas generated by the shift reaction was 172 Nm ³ /h (mass flow rate: 170 kg/h), and the gas temperature at the outlet of the reactor was 430°C.

The externally heated rotary furnace used as the reforming reactor is preheated to 500°C, and the gas generated by the shift reaction is introduced into the reforming reactor, and at the same time, 880 kg/h of crushed and granulated polyethylene, which is a model material of waste plastic, is supplied. , making it warm up to the planned reaction temperature of 800°C. After reaching 800°C, the liquid product trapped by the liquid fuel trap was discharged, and then, the modification reaction of the waste plastic was continued for 1 hour.

The production amount and composition of the gaseous fuel components are obtained from the analysis results of the gas cooled by the gas cooler, and the production amount and composition of the liquid fuel components are obtained from the analysis results of the liquid products captured by the liquid fuel trap, In addition, the LHV is obtained for the gaseous fuel. These results are shown in Table 1.

Since the total amount of shift reaction gas and polyethylene supplied as raw materials is 1050 kg/h, the production ratios relative to the total amount of raw materials supplied are as follows: 36% for gaseous fuel and 62% for liquid fuel. Because it is difficult to directly measure the amount of unreacted polyethylene, if the total amount of gas fuel (380kg/h) and liquid fuel (650kg/h) relative to the supplied conversion reaction gas and polyethylene (1050kg/h) Yield is defined as the polyethylene decomposition rate, then in this invention example 1, the polyethylene decomposition rate is 98%, is a sufficiently high value, basically does not confirm the generation of hydrocarbons above C25, thus it can be seen that polyethylene is efficiently low molecular weight. Through the modification reaction of organic substances, H ₂ O, CO ₂ , and H ₂ are completely consumed, and it can be considered that the four reactions of steam modification, carbon dioxide modification, hydrogenation, and hydrocracking are carried out simultaneously. The LHV of the gaseous fuel produced was 8.9Mcal/Nm ³ , and the calorific value increased to 4.7 times that of the converter gas (1.9Mcal/Nm ³ ).

[Table 1]

*1 Conversion reaction generated gas + polyethylene

· Invention examples 2 to 10

In the same facility as in Invention Example 1, except that the steam flow rate supplied to the shift reactor was changed variously and the reforming reaction temperature was set at two levels of 800°C and 500°C, the same as Invention In the same manner as in Example 1, experiments were carried out on the shift reaction of the converter gas and the polyethylene modification reaction using the gas generated by the shift reaction. The results are shown in Table 2 and FIGS. 4 to 8 .

Fig. 4 shows the relationship between the water vapor concentration of the shift reaction gas and the gasification rate and liquefaction rate of polyethylene modification (reaction temperature: 800°C). Among them, the gasification rate refers to the ratio of the amount of gaseous fuel generated (kg/h) to the total amount (kg/h) of the supplied shift reaction gas and polyethylene. The definition of gaseous fuel is shown in Table 1. For from _H2 to C4. Similarly, the liquefaction rate refers to the ratio of the amount of liquid fuel generated (kg/h) to the total amount (kg/h) of the supplied shift reaction gas and polyethylene. The definition of liquid fuel is shown in Table 1, as From C5 to C24. Fig. 5 shows the relationship between the water vapor concentration of the shift reaction gas and the LHV of gaseous fuel and liquid fuel obtained by modifying polyethylene (reaction temperature: 800°C). Here, the LHV of the liquid fuel is represented by the LHV per volume of the liquid fuel in a gas-converted standard state. Fig. 6 shows the relationship between the water vapor concentration of the gas generated by the shift reaction and the polyethylene decomposition rate by polyethylene modification, especially showing that the polyethylene decomposition rate is the same at the reaction temperature of 500°C and 800°C. FIG. 7 shows the relationship between the carbon dioxide concentration of the gas produced by the shift reaction and the hydrogen concentration of the gaseous fuel obtained by modifying polyethylene (reaction temperature: 800° C.). FIG. 8 shows the relationship between the hydrogen concentration of the gas produced by the shift reaction and the carbon dioxide concentration of the gaseous fuel obtained by modifying polyethylene (reaction temperature: 500° C.).

· Invention Example 11

Fig. 9 shows an overview of equipment used in this embodiment. This facility is equipped with a vertical reforming reactor 9 (inner volume: about 3 m ³ ) having a gas dispersion plate 90 at the bottom, and 880 kg of crushed and granulated polyethylene a is filled in the lowermost layer of the reforming reactor 9 , a metal mesh b (10 mesh) was placed on the upper part, and 800 kg of Ni catalyst c (Ni loading ratio: 10% by mass, carrier: α-Al ₂ O ₃ ) was filled in the upper part. The shift reaction product gas generated in the shift reactor 8 is introduced into the bottom of the reforming reactor 9, is supplied into the reactor through the gas distribution plate 90, and rises in the reactor. The reformed product is discharged from the upper part of the reforming reactor 9, and is separated into a gaseous fuel and a liquid fuel by a liquid fuel trap 10. The separated gaseous fuel is cooled by a gas cooler 11 . It should be noted that the equipment structure from the gas storage tank temporarily storing the converter gas to the shift reactor 8 is the same as that of Invention Example 1.

Using the above-mentioned equipment, the planned reaction temperature in the reforming reactor 9 was set to 750° C., except that, the same conditions as Inventive Example 1 were set (converter gas composition, until shift reaction product gas was obtained) Conditions, conversion reaction gas composition, temperature, flow rate, etc.), carried out polyethylene modification reaction experiment.

The gaseous fuel component, the amount and composition of the liquid product were obtained by the same method as in Inventive Example 1. The results are shown in Table 3. Obtaining substantially the same reaction results as Invention Example 1, it can be considered that the reaction temperature in reforming reactor 9 can be lowered to a temperature 50°C lower than Invention Example 1 (ie, 750°C) due to the effect of adding the catalyst.

[table 3]

*1 Conversion reaction generated gas + polyethylene

· Invention Example 12

As exhaust gas from metallurgical furnaces containing carbon monoxide, blast furnace gas is used. The composition of blast furnace gas after desulfurization and drying treatment is H ₂ : 3% by volume, CO: 23% by volume, CO ₂ : 21% by volume, and N ₂ : 53% by volume. Therefore, nitrogen separation is performed by the PSA method described below , increasing the concentration of carbon monoxide.

In the nitrogen separation by the PSA method, the above-mentioned blast furnace gas was supplied at 136 Nm ³ /h to an adsorption tower filled with 400 kg of Cu ⁺ supported activated carbon as an adsorbent under normal pressure. Desorption is carried out at 7kPa (absolute pressure), and the composition of the desorption gas (=concentrated carbon monoxide blast furnace gas) is H ₂ : <1 vol%, CO: 47 vol%, CO ₂ : 37 vol%, N ₂ : 16 vol% %, the flow rate is 58Nm ³ /h. The carbon monoxide-enriched blast furnace gas and steam at a pressure of 10 kg/cm ² G were supplied to the steam mixer at 58 Nm ³ /h and 73 Nm ³ /h, respectively, and a shift reaction was carried out in the same manner as in Invention Example 1. As a result, a gas having a gas composition of H ₂ : 19% by volume, CO: 2% by volume, CO ₂ : 35% by volume, H ₂ O: 37% by volume, and N ₂ : 7% by volume (shift reaction product gas) was obtained. .

The flow rate of the gas generated by the shift reaction was 130 Nm ³ /h (the mass flow rate was 146 kg/h), and the gas temperature at the outlet of the reactor was 430°C. A polyethylene modification reaction was carried out in the same manner as Invention Example 1, except that the gas generated by the shift reaction was used and the modification reaction temperature was set to 600°C. The reaction results showed that the amount of gaseous fuel produced was 280kg/h, the amount of liquid fuel produced was 590kg/h, the decomposition rate of polyethylene was 85%, and the LHV of gaseous fuel was 7.3Mcal/Nm ³ . Gases can also react efficiently. In addition, since the LHV of the blast furnace gas is 770 kcal/Nm ³ , a gas with 9 times or more combustion heat can be obtained.

·Comparative example 1

In order to study the efficiency of polyethylene modification reaction using a gas with low concentration of water vapor and hydrogen, the composition of _H2 : 1% by volume, CO: 61% by volume, _CO2 : 19% by volume, _H2O : 1 vol%, N ₂ : 18 vol% standard gas, using this gas to carry out polyethylene modification reaction experiments. As a result, at a temperature of 800° C., the polyethylene decomposition rate was 16%, the gasification rate was only 10%, and the liquefaction rate was only 5%, showing that the molecular weight was not substantially reduced.

[Example 2]

· Invention Example 13

A factory test of the method of the present invention was carried out in a steel factory in which two converters 1a, 1b for blowing of different types were connected to a gas storage tank with a capacity of 200,000 ^m3 and an exhaust gas combustion flue for diffusion combustion. .

The exhaust gas generation amount of the converter 1a is 100,000 Nm ³ /hr, and the exhaust gas generation lasts for 90 minutes, and the blowing interval is 90 minutes. Therefore, the time-averaged exhaust gas generation amount is 50,000 Nm ³ /hr. Another converter 1b has an exhaust gas generation of 120,000 Nm ³ /hr. The exhaust gas generation lasts for 20 minutes, and the blowing interval is 70 minutes. Therefore, the time-averaged exhaust gas generation is 27,000 Nm ³ /hr. Therefore, the total time average exhaust gas amount of the converter 1a and the converter 1b is 77,000 Nm ³ /hr. Pipes for utilizing exhaust gas from each workshop in the ironworks were installed downstream of the gas storage tank, and the total exhaust gas utilization amount was 55,000 Nm ³ /hr.

When the level of the gas tank exceeds 95%, the three-way valve faces the exhaust gas combustion flue side to start diffusion combustion, and when the level of the gas tank is below 92%, the diffusion combustion ends. FIG. 10 shows the level change of the gas tank and the combustion emission (instantaneous flow rate) from a certain time until 6 hours have elapsed. According to FIG. 10 , since the cumulative combustion emission during this period was 47,000 Nm ³ /hr, the time-average combustion emission was 7,700 Nm ³ /hr, and the ratio to the time-average exhaust gas amount, that is, the diffusion combustion rate was 10%.

A branch pipe is provided on the gas discharge pipe of the gas storage tank temporarily storing the converter gas so that part of the converter gas can be discharged through the branch pipe. On the downstream side of the branch pipe, a flow regulating valve, a steam mixer, a preheater (for a mixture of converter gas and steam), a shift reactor (cylindrical vertical), a reforming reactor (external heating type) are arranged in sequence. Converter), a gas cooler for cooling reforming reaction product gas equipped with a liquid fuel trap. A waste plastics quantitative input device in the form of a spiral conveyor belt is arranged on the feed side of the above-mentioned modification reactor. In addition, a sampling port and a flow meter were provided on the discharge-side piping of the shift reactor and the discharge-side piping of the cooled gas of the gas cooler.

The average composition of the converter gas in the gas storage tank was H ₂ : 12% by volume, CO: 54% by volume, CO ₂ : 17% by volume, H ₂ O: 1% by volume, and N ₂ : 16% by volume. Converter gas was supplied to the steam mixer at 1770 Nm ³ /hr, and steam at a pressure of 10 kg/cm ² G was supplied as water vapor at 2370 Nm ³ /hr, and after being heated up to 320°C by the preheater, it was introduced into the shift reactor ( Filled with Fe-Cr based high temperature conversion catalyst). Through the shift reaction of the shift reactor, the gas composition of H ₂ : 26% by volume, CO: 2% by volume, CO ₂ : 28% by volume, H ₂ O: 37% by volume, and N ₂ : 7% by volume was obtained ( shift reaction to generate gas). The flow rate of the gas generated by the shift reaction was 4130 Nm ³ /h (the mass flow rate was 4.1 t/hr), and the gas temperature at the outlet of the reactor was 430°C.

The externally heated rotary furnace used as the reforming reactor was heated to 500°C in advance, and the gas generated by the shift reaction was introduced into the reforming reactor, and at the same time, 21t/hr was supplied as a model substance of waste plastics, which was crushed and processed into granules. Ethylene is heated to the planned reaction temperature of 800°C. After reaching 800°C, the liquid product trapped by the liquid fuel trap is discharged, and then the modification reaction of waste plastic is continued for 1 hour.

The production amount and composition of the gaseous fuel components are obtained from the analysis results of the gas cooled by the gas cooler, and the production amount and composition of the liquid fuel components are obtained from the analysis results of the liquid products captured by the liquid fuel trap, In addition, the LHV is obtained for the gaseous fuel. These results are shown in Table 4.

Since the total amount of shift reaction gas and polyethylene supplied as raw materials is 25.1t/hr, the production ratios relative to the total amount of raw materials supplied are as follows: 36% for gaseous fuel and 62% for liquid fuel. Since it is difficult to directly measure the amount of unreacted polyethylene, if the gaseous fuel (9.05t/hr) and liquid fuel (15.65t/hr) are compared to the total amount of gas and polyethylene supplied by the shift reaction (25.1t/hr hr) is defined as the polyethylene decomposition rate, and in this Invention Example 1, the polyethylene decomposition rate is 98%, which is a sufficiently high value, and basically no generation of hydrocarbons of C25 or higher is confirmed. , Polyethylene is effectively reduced in molecular weight. Through the modification reaction of organic substances, H ₂ O, CO ₂ , and H ₂ are completely consumed, and it can be considered that the four reactions of steam modification, carbon dioxide modification, hydrogenation, and hydrocracking are carried out simultaneously. The LHV of the gaseous fuel produced was 8.9Mcal/Nm ³ , and the calorific value increased to 4.7 times that of the converter gas (1.9Mcal/Nm ³ ).

[Table 4]

*1 Conversion reaction generated gas + polyethylene

What Fig. 11 shows is the level change of the gas storage tank and the amount of combustion emission during the factory test, and Fig. 12 shows the cumulative combustion emission obtained from Fig. 10 (existing example) and Fig. 11 (example of the present invention) The change. It can be seen from Fig. 11 and Fig. 12 that by using the method of the present invention, the cumulative combustion emission is reduced to 35,000 Nm ³ /hr. As a result, the time-average combustion emission rate was reduced to 5800 Nm ³ /hr, and the combustion emission rate was reduced to 7.6%, and the effect of the present invention is clear. The past time-average combustion emission shown in FIG. 10 was 7700 Nm ³ /hr, and the combustion emission decreased by 1900 Nm ³ /hr (equivalent to 16 million Nm ³ /year) on a time-average basis. The discharge of converter gas to the shift reactor was 1770Nm ³ /hr, and the actual value of the combustion emission was slightly increased, but it can be considered an error caused by the time average of the combustion emission obtained from the relatively short-term change.

Claims (8)

1. a degraded method for organic substance, the method comprises:

Make it carry out transformationreation by add excessive water vapour in the waste gas that contains carbon monoxide (g0) producing in metallurgical furnace, the mixed gas (g) of water vapour that formation contains hydrogen that transformationreation generates and carbonic acid gas and do not consume in transformationreation, this mixed gas (g) is contacted with organic substance, organic substance modification is carried out degraded, water vapor concentration is that 5～70 volume %, hydrogen concentration are that 10～40 volume %, gas concentration lwevel are 10～40 volume % in described mixed gas (g).

2. the degraded method of organic substance according to claim 1, wherein, waste gas (g0) is, the waste gas that contains carbon monoxide and nitrogen by producing from metallurgical furnace, at least a portion nitrogen is separated to the waste gas that has improved carbon monoxide concentration.

3. the degraded method of organic substance according to claim 1 and 2, wherein, the organic substance for the treatment of modification is to be selected from more than one in plastic waste, oil-containing mud, waste oil.

4. a manufacture method for fuel, the method comprises:

The modifier of the organic substance that the degraded method of the organic substance by described in any one in claim 1～3 is obtained reclaims with the form of geseous fuel and/or liquid fuel.

5. the waste gas that metallurgical furnace produces utilize a method, the method comprises:

At the gas-holder with the waste gas that contains carbon monoxide (g0) that temporary transient storage produces off and on from metallurgical furnace, the waste gas (g0) that is stored in this gas-holder is delivered to gas and is utilized the pipe arrangement of supplying gas of equipment, carry out in the exhaust gas apparatus of flare stack of diffusion combustion with the waste gas (g0) that can not be stored in gas-holder, by a part of pipe arrangement combustion gas (g0) that supply gas from the described pipe arrangement branch of supplying gas, make it carry out transformationreation to the excessive water vapour of the middle interpolation of this waste gas (g0), formation contains hydrogen and the carbonic acid gas that transformationreation generates, mixed gas (g) with the water vapour not consuming in transformationreation, this mixed gas (g) is contacted with organic substance, organic substance modification is carried out degraded, in described mixed gas (g), water vapor concentration is 5～70 volume %, hydrogen concentration is 10～40 volume %, gas concentration lwevel is 10～40 volume %.

6. the waste gas that metallurgical furnace according to claim 5 produces utilize method, wherein, add excessive water vapour make its waste gas that carries out transformationreation (g0) be by from metallurgical furnace produce the waste gas that contains carbon monoxide and nitrogen at least a portion nitrogen is separated to the waste gas that has improved carbon monoxide concentration.

7. the waste gas producing according to metallurgical furnace described in claim 5 or 6 utilize method, wherein, the organic substance for the treatment of modification is to be selected from more than one in plastic waste, oil-containing mud, waste oil.

8. a manufacture method for fuel, the method comprises:

The modifier of the organic substance obtaining by the method described in any one in claim 5～7 is reclaimed with the form of geseous fuel and/or liquid fuel.