JPS6158509B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coal processing method for obtaining oily components from coal and an apparatus suitable for carrying out the method. As a method of obtaining liquid oil components from coal, the tar produced when coal is carbonized at a temperature of about 500 to 600°C is recovered. A so-called low-temperature carbonization method is known. However, the tar content obtained by this method is about 10%, and although the yield of tar content is higher than that of high-temperature carbonization, the carbon in the coal, which is recovered as a by-product during coke production, is reduced by removing volatile matter. Most of it is turned into coke, and it is difficult to say that it is an efficient way to obtain tar. In recent years, the development of petroleum alternative energy has been actively carried out, and for this reason, in the field of coal liquefaction, the so-called C, O, E, D method (Char-Oil-Energy-
Development Process) has been proposed. This process basically belongs to the carbonization liquefaction method, and by carbonizing coal in multiple stages, gas and
It is designed to obtain liquid and chia,
The feature is that a four-stage fluidized carbonization furnace is used to carbonize coal while heating and fluidizing it sequentially from a low temperature to a high temperature carbonization furnace. However, with this method, it is difficult to maintain thermal balance and material flow balance between the fluidized beds during operation, and it is also necessary to operate the carbonization furnace itself while preventing softening and melting of the coal ash. However, there are disadvantages such as the risk of sticking due to softening and melting of the ash. In addition, the liquid component obtained by this method is only about 20% in the case of coking coal (Illinois No. 6 coal, volatile content 45%), which is by no means a high yield compared to the difficulty of operation. It's hard to say. Furthermore, the gas produced by this method is CO ₂
is large, therefore the calorific value is not high, and since the content of H ₂ is large, it is presumed that the decomposition of hydrocarbon components is large. In order to obtain liquid oil from coal, there is a direct liquefaction method that is currently the mainstream technology being developed with the aim of industrialization. In this method, hydrogen is added to a slurry of powdered coal and a solvent with high solubility for coal at high temperature and pressure to hydrogenate and liquefy the coal. Although this method has a very high yield of liquefied products and is excellent, it requires indirect heating of the coal slurry to 400 to 450°C in the process, which tends to cause clogging in the heating pipes.
Hydrogen production and recovery equipment is required because large amounts of hydrogen are used, there are safety issues when handling hydrogen, and many advanced and expensive equipment are required, such as means of transporting high viscosity slurry. There are some difficulties, such as: The present invention was devised in view of the problems of the conventional method, and is a new method that can obtain liquid oil from coal at low cost and at a relatively high yield without causing the problems of the conventional method. The aim is to provide a method for For this reason, the present invention provides a system in which a coal-water slurry is fed into a pressurized reaction vessel equipped with a submerged combustion device, so that reducing combustion gas is produced under pressurized conditions with less than the combustion equivalent of oxygen supplied. The basic feature is that the reaction product is taken out of the container and the liquid oil is recovered from the reaction product using a separator. Further, as a device for suitably carrying out such a method, a pulverizer is provided with coarsely pulverized coal, and pulverizes it in the presence of water to form a coal-water slurry;
A pressurized reaction vessel equipped with a submerged combustion device therein and to which the coal-water slurry is supplied from a pulverizer through a supply pipe, and a supply pipe extending from the upper part of the pressurized reactor. A first separation device that separates the reaction product into a gaseous component and a liquid component containing solids, and a supply pipe in which the liquid component separated by the first separation device is supplied with the reaction product in the container. a second separator that separates and recovers the liquid oil that is supplied through the pipe, a return pipe that returns the remaining liquid component after recovering the liquid oil to the pulverizer as slurry water, and a pressurized reaction vessel. Another basic feature is that it is equipped with a processing device that removes CO ₂ components from the container liquid taken out from the container. The present invention is a so-called coal-water slurry in which fine coal powder is suspended in water or an aqueous solution, which is submerged in combustion under specific conditions to liquefy coal and recover it. The coal-water slurry is burnt under pressurized conditions in a pressurized reaction vessel having a submerged combustion device and under combustion conditions that form a reducing atmosphere, i.e. less than the fuel equivalent of oxygen produces reducing combustion gases. The coal is combusted in liquid, thereby producing liquid oil from the coal, and this liquid oil is separated and recovered by a separator. Submerged combustion technology is widely known as a heat treatment technology for liquids, and it achieves excellent thermal efficiency by directly heating the liquid, while being easy and simple to operate, with few associated difficulties. It has the advantage of Therefore, as a result of repeated experiments and studies to apply this submerged combustion method to the liquefaction of coal, the present inventors turned coal into a water slurry, and heated this coal-water slurry under pressurized conditions with less than the combustion equivalent of oxygen. It has been found that liquid oil can be obtained at a high yield through the following reaction by causing reductive submerged combustion. That is, in the reaction vessel, coal, hydrocarbons, or carbonaceous materials contained in the coal slurry as fuel undergo various reactions to produce liquid oil. (1) Coal and hydrocarbons are partially destroyed by reductive combustion reactions.
It generates CO and _H2 , and some of it produces liquid oil through thermal decomposition. CmHn+O ₂ →CO+H ₂ +H ₂ O (small amount) +CO ₂ (small amount) + Cm′Hn′ (oil: liquid component) ...Pyrolysis reaction (2) Carbon materials generate CO by reaction with oxygen. C+1/2O ₂ →CO (3) CO reacts with water to produce H ₂ . CO+H ₂ O→H ₂ +CO ₂ (4) H ₂ reacts with the remaining coal and hydrocarbons to turn it into oil or lighten it. CmHn＋H ₂ →Cm″Hn″
...Hydrogenation reaction of coal or hydrocarbons Cm′Hn′＋H ₂ →CmHn
Hydrogenation reaction of produced liquid oil In the submerged combustion according to the present invention, reducing gases such as CO and H ₂ are produced by supplying oxygen in an amount less than the combustion equivalent, and the combustion is performed under pressurized conditions. The action of H ₂ described above effectively liquefies the coal, and in addition, it is possible to prevent the liquid components of the coal generated by the reducing atmosphere from burning. Preferred embodiments of the present invention are as follows. (1) Supplying auxiliary fuel to the coal-water slurry under pressurized conditions. (2) A reducing gas heated to a high temperature is supplied to the coal-water slurry under pressurized conditions. (3) Adding a water-soluble alkali component and/or Fe component to the coal-water slurry. The modes of submerged combustion include supplying fuel from the outside and burning only this fuel, if the heated liquid contains flammable components, use these combustible components as fuel, and adding fuel to the heated liquid. If the liquid contains flammable components, supply fuel from outside and also use the flammable components in the liquid as fuel.
Three aspects are possible. The present invention aims at partial combustion of a coal-water slurry, but at the same time, the coal itself in the slurry may be used as a fuel, that is, the mode (2) above may be carried out.
The case of (1) above corresponds to the aspect of
When combustion is insufficient with only coal in the slurry, auxiliary fuel such as hydrocarbons such as petroleum may be supplied. Furthermore, as described above, in the present invention, submerged combustion is performed under conditions that generate a reducing atmosphere, and this reducing atmosphere is used to effectively liquefy coal. In the case of (2) above, this reducing gas (CO and/or H ₂ ) is supplied from the outside. This reducing gas is preferably supplied in a high temperature state. Further, under the conditions (3) above, a water-soluble alkali component is added to the coal-water slurry as a reaction aid, and Fe is added as a catalyst. Examples of water-soluble alkali components include hydroxides and carbonates of Na or K, which may be added singly or in combination. By adding these components, the vapor pressure of the slurry in the reaction vessel can be reduced, so that the degree of pressurization required to maintain the high temperature is small, and a reduction in power can be expected. Also,
Since the aqueous solution (slurry) containing these components has the ability to absorb CO ₂ , it is possible to reduce the CO ₂ concentration in the gas components in the reactor and increase the calorific value of the gas. In particular, Na and K are industrial chemicals that are easily available and are highly water soluble, and furthermore, these acidic carbonates can be easily converted into CO ₂ by heating.
Since the carbonate is released and regenerated into carbonate having CO ₂ absorption ability, it is easy to remove CO ₂ from outside the reactor system. Further, Fe reacts with water to generate more active H ₂ (Fe+H ₂ O=FeO+H ₂ ), and also contributes to increasing the yield of liquid components as a catalyst. Fe
may be added in the form of iron oxide, and this iron oxide comes into contact with the hot reducing combustion gas in the combustion zone.
It is reduced to Fe. Furthermore, it is necessary to suspend Fe in the coal-water slurry, and for this reason it is added in the form of fine particles. In the present invention, the reaction products generated by submerged combustion as described above are taken out of the container,
A separator recovers liquid oil from the reaction product. Next, the apparatus of the present invention and the coal liquefaction and recovery method using the same will be specifically explained based on the drawings. The apparatus of the present invention includes a pulverizer 1 for turning coal into slurry, a pressurized reaction vessel 2 equipped with a submerged combustion device inside, and a pulverizer for separating the reaction products in the vessel into mainly gaseous and liquid components. 1 separation device 3, a second separation device 4 that separates and recovers liquid oil from the obtained liquid component, and a return pipe 5 that returns the remaining liquid component after separation of the liquid oil to the pulverizer as slurry water. Its main components include a processing device 20 that removes CO ₂ components from the liquid in the container. The pulverizer 1 is supplied with coarsely pulverized coal and pulverizes it into a coal-water slurry in the presence of water. The fine pulverizer 1 is supplied with coal that has been primarily pulverized in a coarse pulverizer 6, which is a pre-process, and is also supplied with a second separator 4 as described later.
Water for slurrying is supplied from etc. The submerged combustion device 7 in the pressurized reaction vessel 2 is installed at the bottom side of the vessel, and oxygen gas (or air) is supplied from a pipe 8, and auxiliary fuel is supplied from a pipe 9. It's summery. A pipe line 10 for taking out reaction products is connected to the upper part of the pressurized reaction vessel 2. The reaction product is a high-temperature, high-pressure gas containing liquids, solids, etc., and is discharged from the upper part of the container through the pipe 10 to the separation tank side. Further, a conduit 11 is connected to the lower part of the container for taking out the liquid at the inner bottom of the container. Further, the coal-water slurry from the pulverizer 1 is forced into the center of the pressurized reaction vessel 2 through a pipe 12. The reaction product is supplied to the first separation device 3 through a pipe line 10.
A cooling tube 13 is provided in the middle of the pipe line 10. In the separation device 3, the reaction product is separated into a mainly gaseous component and a liquid component containing solids, and the separated gaseous component is sent to the next step via a pipe 14. A pressure reducing device 15 is interposed in the middle of this pipe line 14. On the other hand, the separated liquid component is transferred to the second separation device 4 through the pipe line 16.
sent to. Note that a pressure reducing device 17 is also provided in the middle of this pipe line 16. Further, a part of the liquid component is returned to the pressurized reactor 2 to maintain the liquid component in the reaction vessel. In the second separation device 4, liquid oil is separated from the liquid components (including solids) supplied from the pipe 16, and the separated liquid oil is taken out of the system from the pipe 18 as a product of coal liquefaction. It can be done. on the other hand,
The remaining liquid component after recovering the liquid oil is sent to the return pipe 5.
The water is returned to the pulverizer 1 as part of the slurry water. In this embodiment, a part of this remaining liquid component is taken out of the system from the pipe line 51 in the middle of the pipe line 5 and sent to another process. The pipe line 1 connected to the bottom of the pressurized reaction vessel 2
1 is branched, and one branch pipe 111 is connected to the pressurized reaction vessel 2, and a cooler 1 is installed on the way.
9 is provided to cool and circulate the liquid (coal-water slurry) in the container and adjust the temperature of the liquid in the container. The other branch pipe line 112 is connected to a processing device 20 (flash device). A pressure reducing device 21 is provided in the middle of this branch pipe 112. This processing device 20 performs a process of releasing CO ₂ gas from acidic carbonate in the liquid and returning it to carbonate by using a liquid pressure reduction device. The generated CO ₂ gas is sent out of the system through a pipe 22. I am beginning to be guided by this. A part of the treated liquid is supplied to the pulverizer 1 through a pipe line 23 as part of slurry water. On the other hand, the other part of the liquid is sent to the separation device 24 through the pipe line 231, where residual components including solids are removed, and then further transferred to the recovery device 25.
Na or K is recovered and sent out of the system. The residual components separated by the separator 24 are sent out of the system through a conduit 26 for recovery of active ingredients or for other purposes. In addition, water-soluble alkali components such as Na and K recovered in the form of concentrated liquid or crystals by the recovery device 25 are sent to the pulverizer 1 via a transfer path 27 (pipe, etc.), and the coal-water It is now added to the slurry. Further, water-soluble alkali components such as Na or K are supplied to the pulverizer 1 from outside the system through a path 28, and Fe components are supplied through a path 29, and these are added to the coal-water slurry. In addition, a pipe line 30 is inserted into the pressurized reaction vessel 2, and if necessary, reducing gas such as H ₂ and/or CO is preheated to a predetermined temperature from outside the system and then sent to the bottom of the vessel. There is. Note that any suitable submerged combustion device 7 can be used, but in the case of using coal as fuel, for example, the method proposed by the present inventors in Utility Model Application Publication No. 59-37909 (Utility Model Publication) Application No. 57-129813) or Utility Model Application Publication No. 59-37910 (Publication Application No. 57-129814)
A submerged combustion device such as that shown in No. 1) can be used. The former device has an oxygen-containing gas supply pipe, an inner pipe, and an outer pipe, which are provided approximately concentrically from the inside, and between the oxygen-containing gas supply pipe and the inner pipe, and between the inner pipe and the outer pipe, respectively. It consists of a submerged burner with an auxiliary fuel supply channel and a slurry supply channel, and an outer cylinder that has openings at the top and bottom and is provided to surround the submerged burner. The inside of the outer cylinder is configured as a combustion chamber, and oxygen-containing gas (oxygen gas or air, etc.) is supplied from the oxygen-containing gas supply pipe, and auxiliary fuel such as coke oven gas is supplied from the auxiliary fuel supply channel. , and a coal-water slurry is supplied from the slurry supply channel, respectively.
It is designed to burn in liquid. The latter device has a container that has a discharge port at the top and is immersed in the liquid, and a discharge port at the bottom and an injection nozzle for combustion-supporting gas (oxygen-containing gas) supplied from outside the container. A combustion tube arranged in the combustion tube, a cylinder whose upper and lower ends are open on the outside, and whose lower end extends below the discharge port, and a cylinder which is guided from outside the container and extends spirally to the outside of the cylinder. It consists of a slurry supply pipe whose end is connected to the upper part of the combustion cylinder, and the cylinder forms a circulation passage in the container, which consists of a downward flow passage inside the cylinder and an upward flow passage outside the cylinder. Oxygen-containing gas is supplied into the combustion cylinder from an injection nozzle, and a coal-water slurry is supplied from a slurry supply pipe to perform submerged combustion. Basic experiment example: Put 500g of coal crushed into 200 mesh into an autoclave, create a nitrogen atmosphere inside, and heat it externally.
The mixture was shaken at 370°C for 24 hours, and a slurry made by adding 1000 g of water to 500 g of coal crushed into 200 meshes was shaken under the same conditions to obtain the following results.

【table】

[Table] As is clear from this experimental example, the yield of liquid oil can be made higher by treating the coal as a coal-water slurry than by treating the pulverized coal as it is. Experimental example Coal-water slurry was placed in a heat-resistant cylindrical reactor that could be indirectly cooled, and the coal-water slurry with a concentration of 55% was supplied to the bottom of the reactor as fuel, and at the same time oxygen gas was supplied, and the reaction was carried out for 1 hour. Burned in liquid. The reaction product was discharged from the top of the reactor, and the liquid oil was separated and recovered through a pressure reduction device and an indirect cooler.The oil remaining in the reaction vessel was also collected and weighed together to measure the amount of oil produced. . The table below shows the amount of oil produced by varying the pressure inside the reaction vessel and the amounts of NaOH and Fe added. The amount of oil produced was expressed as the amount of benzene extracted. The samples used in the experiment are as follows. (1) Coal particle size: 200 mesh 100% passed Brand: Pacific Coal Industry analysis: Moisture 5.5% Ash 5.0% Volatile content 48.2% Fixed carbon 51.2% (2) Water: Tap water (3) NaOH: Reagent grade 1 (4) Iron: 200 mesh finely pulverized to 100% passage

[Table] As is clear from the above table, liquid oil can be recovered at a high yield by performing submerged combustion under pressurized conditions and while supplying a relatively small amount of oxygen. It is also seen that a higher oil yield can be obtained by adding NaOH as an auxiliary agent and Fe as a catalyst. According to the present invention described above, since coal is treated using submerged combustion technology, it requires extremely simple equipment compared to direct liquefaction methods, etc., and hydrogen produced by partial combustion in the reactor can be effectively used. It has the advantage of not requiring a separate supply of hydrogen as it can be used for water, the temperature required for processing to be achieved with high thermal efficiency, and safe operation as most of the flow is transferred by water slurry.

[Brief explanation of the drawing]

The drawing is a flow sheet schematically illustrating the apparatus of the invention. In the figure, 1 is a pulverizer, 2 is a pressurized reaction vessel, 3 is a first separation device, 4 is a second separation device,
5 is a return pipe, 7 is a submerged combustion device, and 20 is a processing device.

Claims (1)

[Claims] 1. A coal-water slurry is supplied into a pressurized reaction vessel equipped with a submerged combustion device, so that reducing combustion gas is produced by supplying oxygen of less than the combustion equivalent under pressurized conditions. 1. A method for treating coal, which comprises: burning the coal in a liquid, taking out the resulting reaction product outside the container, and recovering liquid oil from the reaction product using a separation device. 2. The method for treating coal according to claim 1, characterized in that the coal-water slurry itself is submerged in combustion as a fuel. 3. The method for treating coal according to claim 1 or 2, characterized in that submerged combustion is carried out while supplying auxiliary fuel to the coal-water slurry under pressurized conditions. 4. The method for treating coal according to claim 1, 2 or 3, characterized in that a high temperature reducing gas is supplied to the coal-water slurry under pressurized conditions. 5. The method for treating coal according to claim 1, 2, 3 or 4, characterized in that a water-soluble alkali component and/or Fe component is added to the coal-water slurry. 6 Coarsely pulverized coal is supplied, and the pulverizer is equipped with a pulverizer that pulverizes the coal in the presence of water to form a coal-water slurry, and a submerged combustion device inside. A pressurized reaction vessel is supplied with the coal-water slurry, and a reaction product is supplied in the vessel through a pipe extending from the upper part of the pressurized reaction vessel, which mainly contains gas components and solids. a first separator that separates the liquid component contained in the oil; and a second separator that separates and recovers the liquid oil from which the liquid component separated by the first separator is supplied via a pipe.
separation device, a return pipe that returns the remaining liquid component after liquid oil recovery to the pulverizer as slurry water, and a process that takes out the liquid inside the pressurized reaction container from the bottom of the container and removes the CO ₂ component. A coal processing device comprising: