JP7311777B2 - Coke oven gas treatment device and coke oven gas treatment method - Google Patents

Description

The present invention relates to a coke oven gas treatment apparatus and a coke oven gas treatment method.

When coal (coking coal) is dry-distilled to produce coke, coke oven gas (COG) and tar are generated as by-products resulting from volatile matter in the coal. Coke oven gas contains about 3% of impurities such as aromatic compounds and environmental pollutants. Aromatic compounds include tar mist, naphthalene, and light oil, and environmental pollutants include hydrogen cyanide (HCN), ammonia (NH ₃ ), hydrogen sulfide (H ₂ S), and the like.

Coke oven gas containing these impurities is treated according to the purpose, such as recovery as chemical products, use as fuel, prevention of equipment corrosion problems, and environmental measures. It is roughly divided into the gas cooling process and the latter gas refining process.

In the gas cooling step, high-temperature coke oven gas, which is dry distillation exhaust gas of raw coal, is cooled. Cooling treatment of coke oven gas includes indirect cooling treatment by an indirect gas cooler and direct cooling treatment by a direct gas cooler. In the indirect cooling process, saturated water vapor contained in the coke oven gas is condensed by the cooling water passing through the tube, and a condensate containing impurities is generated. In the direct cooling process, the supplied cooling water for direct cooling and the saturated steam contained in the coke oven gas are condensed to generate a condensate containing impurities. The condensate is recovered as recovered water and separated into a tar mixed liquid and ammonia water (water containing an ammonia component). A certain amount of ammonia water is used to cool the coke oven gas, and the rest is disposed of.

The gas refining process consists of a desulfurization process for the purpose of desulfurization as a countermeasure against corrosion of pipes and environmental measures, and a denitrification process for the purpose of removing nitrogen compounds that cause corrosion of pipes and NOx generation (for example, removal of ammonia). target _NH3 removal process), light oil recovery process for the purpose of light oil recovery, etc. Note that the order of these steps varies depending on the steelworks.

As for the gas cooling process, the following techniques are disclosed.
Patent Literature 1 describes that coke oven gas is cooled by a receiver and a cooling tower that spray circulating water. Further, Patent Document 2 describes that coke oven gas is cooled by an indirect primary gas cooler and a direct primary gas cooler that cools by spraying circulating cooling water.

Japanese Patent Publication No. 58-30356 JP-A-6-73386

As described above, the gas cooling device for performing the gas cooling process in the first half is designed for the purpose of cooling the coke oven gas, not for the purpose of desulfurization or denitrification. The desulfurization and denitrification processes are entrusted to the gas purifier that carries out the latter gas purification process. As described in Patent Literature 1 and Patent Literature 2, in the gas cooling process, dry maine , indirect type primary gas cooler, and direct type primary gas cooler, a certain amount of recovered water is circulated and used effectively.

In this manner, the gas cooling device is configured to reintroduce the recovered water into the coke oven gas as spray water for cyclical use. The sulfur content and nitrogen content dissolved in the recovered water circulate and return to the coke oven gas, so the components in the coke oven gas introduced from the inlet side of the gas cooling process are maintained as they are, and the gas cooling process outlet The concentrations of sulfur and nitrogen on the side are determined by the amounts of sulfur and nitrogen in the raw coal.

Here, the coke oven gas treatment apparatus for treating coke oven gas is constructed together with the coke oven as ancillary equipment of the coke oven. Therefore, the processing capacity of the coke oven gas treatment equipment is set based on the components of the coking coal used in the coke oven at the time of construction. That is, the processing capacity in the gas refining process for desulfurization and denitrification is also set based on the components of the coking coal used in the coke oven at the time of construction.

If the composition of the coking coal is the same as it was at the time of construction, it can be processed without any problems. Charcoal is now being used. Since inferior coal often contains a large amount of sulfur and nitrogen, the amount of sulfur and nitrogen in the coke oven gas at the inlet of the gas cooling process increases. A situation is occurring in which the concentrations of sulfur and nitrogen are increasing.

However, in existing facilities, the processing capacity of the gas purifier is set at the time of construction as described above, and there is a limit. When the amounts of sulfur and nitrogen exceed the processing capacity of the gas refinery, the NOx concentration and SOx concentration in the exhaust gas after the gas purification process increase, making it impossible to comply with environmental regulations. Therefore, in order to suppress the increase in NOx concentration and SOx concentration, it is necessary to take measures such as suppressing the amount of inexpensive inferior coal used or improving the processing capacity in the gas refining process. Measures that can be taken to improve the processing capacity are, for example, the installation of additional gas purifiers for the desulfurization process and the denitrification process, but there is the problem of large-scale capital investment. Also, the concentrations of sulfur and nitrogen do not necessarily double, and it is sufficient to be able to cope with an increase of about 10 to 30%, for example. Therefore, it has been desired to be able to cope with this problem with a simpler facility than adding a gas purifier.

An object of the present invention is to provide a coke oven gas treatment apparatus and a coke oven gas treatment method capable of treating coke oven gas generated during the carbonization of coking coal such as poor quality coal containing a large amount of sulfur and nitrogen. is.

The gist of the present invention is as follows.
(1) A coke oven gas treatment apparatus for recovering coke oven gas generated during carbonization of coal and removing impurities,
a gas cooling device for cooling the coke oven gas;
A gas purification device provided downstream of the gas cooling device and performing purification processing of the coke oven gas after the cooling treatment,
The gas cooling device includes an impurity removal device that removes at least one of nitrogen compounds and sulfur compounds, which are impurities contained in the recovered water, from part or all of the recovered water recovered from the gas path; with
A coke oven gas treatment apparatus characterized by:
Here, the gas path is a path through which coke oven gas introduced from the coke oven flows, and includes a dry main, a cooler, and piping between the dry main and the cooler.
(2) The coke oven gas treatment apparatus according to (1), characterized in that the recovered water passing through the impurity removal device is put into the coke oven gas.
(3) The gas cooling device has a chiller-type cooler provided on the most downstream side thereof,
The coke oven gas treatment apparatus according to (1) or (2), wherein the impurity removal device removes the impurities contained in the water recovered from the chiller cooler.
Here, the chiller type cooler is equipped with a heat exchanger for cooling the COG contact refrigerant (cooling medium that exchanges heat with the coke oven gas) for cooling the coke oven gas, and this heat exchanger artificially cools It means that the COG contact refrigerant is cooled using the cooling medium.
(4) the chiller-type cooler is a chiller-type indirect cooler;
(3) characterized in that the gas cooling device has, instead of the impurity removal device, a discharge treatment device for discharging the recovered water recovered from the chiller-type indirect cooler from the gas cooling device. The coke oven gas treatment apparatus according to .
(5) further comprising a control device,
The gas purifier has one or both of a desulfurization device and a denitrification device,
The gas cooling device or the gas purifying device includes an H ₂ S concentration measuring device for measuring the H ₂ S concentration in the coke oven gas downstream of the chiller type cooler, and a coke oven downstream of the chiller type cooler. Having one or both of an NH ₃ concentration measuring device for measuring the NH ₃ concentration in the gas,
The control device can control the cooling temperature by the chiller-type cooler based on one or both of the measured value measured by the H ₂ S concentration measuring device and the measured value measured by the NH ₃ concentration measuring device. The coke oven gas treatment apparatus according to (3) or (4), characterized in that:
(6) Control of the cooling temperature of the coke oven gas by the chiller type cooler,
The coke oven gas treatment apparatus according to claim 5, characterized by adjusting the temperature of the heat exchange refrigerant used in the chiller type cooler.
Here, the heat exchange refrigerant is a cooling medium that exchanges heat with a COG contact refrigerant (a cooling medium that exchanges heat with coke oven gas).
(7) A coke oven gas treatment method using the coke oven gas treatment apparatus according to (3) or (4),
The gas purifier has one or both of a desulfurization device and a denitrification device,
The gas cooling device or the gas purification device includes an H ₂ S concentration measuring device for measuring the H ₂ S concentration in the coke oven gas downstream of the chiller type cooler, and a coke oven downstream of the chiller type cooler. Having one or both of an NH ₃ concentration measuring device for measuring the NH ₃ concentration in the gas,
The cooling temperature of the chiller-type cooler is controlled based on one or both of the measured value measured by the H ₂ S concentration measuring device and the measured value measured by the NH ₃ concentration measuring device. Coke oven gas treatment method.
(8) Control of the cooling temperature of the coke oven gas by the chiller type cooler,
The method for treating coke oven gas according to (7), characterized in that it is performed by adjusting the temperature of a heat exchange refrigerant used in the chiller type cooler.
Here, the heat exchange refrigerant is a cooling medium that exchanges heat with a COG contact refrigerant (a cooling medium that exchanges heat with coke oven gas).

According to the present invention, in a coke oven gas treatment apparatus or a coke oven gas treatment method for treating coke oven gas discharged from a coke oven, by removing impurities contained in recovered water, the gas purification apparatus or gas purification is performed. The concentration of impurities in the coke oven gas before being introduced into the process can be reduced.

It is a figure which shows an example of the whole structure of the conventional coke oven gas treatment apparatus. FIG. 4 is a diagram showing the results of a cooling experiment of coke oven gas; BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows a part of example of a structure of the coke oven gas treatment apparatus (using a chiller type direct cooler) which concerns on the 1st Embodiment of this invention. FIG. 2 is a diagram showing a part of an example of a configuration of a modification of the coke oven gas treatment apparatus (using a chiller-type direct cooler) according to the first embodiment of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows a part of example of a structure of the coke oven gas treatment apparatus (using a chiller type indirect cooler) which concerns on the 1st Embodiment of this invention. FIG. 3 is a view showing a part of an example of a configuration of a modification of the coke oven gas treatment apparatus (using a chiller type indirect cooler) according to the first embodiment of the present invention; It is a figure which shows an example of the whole structure of the coke oven gas treatment apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the whole structure of the coke oven gas treatment apparatus which concerns on the 3rd Embodiment of this invention. FIG. 10 is an explanatory diagram illustrating a modification of the coke oven gas treatment apparatus according to the third embodiment of the present invention;

First, an example of a conventional coke oven gas treatment apparatus will be described below with reference to the accompanying drawings, and then preferred embodiments of the present invention will be described in detail. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

FIG. 1 is a diagram showing the overall configuration of a conventional coke oven gas treatment apparatus. A coke oven gas treatment apparatus 1 shown in FIG. 1 is an example of a coke oven gas treatment apparatus. In the figure, the two-line piping path indicates the flow path of the coke oven gas, the thick solid-line arrow indicates the flow of recovered water recovered from the coke oven gas, and the thin solid-line arrow indicates the flow of water supplied from the outside for cooling. It shows the flow of water (seawater) Here, the recovered water is the water recovered in the gas path, and includes the tar mixture.

As shown in FIG. 1, the coke oven gas treatment apparatus 1 includes a gas cooling apparatus 2 for cooling the coke oven gas introduced from the coke oven, and a gas purification apparatus for purifying the coke oven gas after the cooling treatment. a device 3; The coke oven gas is first guided to the gas cooling device 2 and subjected to cooling treatment, and then guided to the gas purification device 3, and after the gas purification treatment, the energy is reused as appropriate. will be

The gas cooling device 2 includes an ascending pipe descending portion 4A extending from the coke oven, a dry main 4 and gas coolers 5 (an indirect gas cooler 5a and a direct gas cooler 5b), and a decanter 6. In the coke oven gas treatment apparatus 1 shown in FIG. 1, both the indirect gas cooler 5a and the direct gas cooler 5b are provided as the gas cooler 5. It is good if there is.

In the ascending pipe descending section 4A, sprayed water is directly sprayed onto the coke oven gas of about 800°C introduced from the coke oven to the dry main 4 to cool the coke oven gas to 70°C to 80°C. The cooled coke oven gas is introduced to the indirect gas cooler 5a. In addition, the sprayed water accumulated at the bottom of the dry main 4 due to spraying of the sprayed water in the rising pipe descending portion 4A and the condensed liquid condensed by cooling are collected in the decanter 6 from the pipe between the dry main 4 and the indirect gas cooler 5a. It is recovered as water A. Here, among the recovered waters A to C recovered in the decanter 6, ammonia water, which is water containing an ammonia component, is circulated for the sprayed water of the dry main 4, although the details will be described later.

The indirect gas cooler 5a is a device that allows externally supplied water (COG contact refrigerant 41) to pass through a tube and indirectly contact the coke oven gas, thereby cooling the coke oven gas through heat exchange. Here, the COG contact refrigerant 41 is a cooling medium that exchanges heat with coke oven gas (COG). For the COG contact refrigerant 41 of the indirect gas cooler 5a, natural cold water having a temperature lower than that of the coke oven gas, such as seawater, is used. The coke oven gas of about 75°C introduced from the dry main 4 is cooled to about 50°C by the indirect gas cooler 5a. The cooled coke oven gas is introduced directly to the gas cooler 5b. Also, the condensed liquid condensed by cooling in the indirect gas cooler 5 a accumulates at the bottom of the indirect gas cooler 5 a, is recovered as recovered water B, and is collected in the decanter 6 .

The direct gas cooler 5b is a device that sprays sprinkled water (COG contact refrigerant 41) directly onto the coke oven gas, brings it into contact with the coke oven gas, and cools the coke oven gas through heat exchange. The direct gas cooler 5b cools the coke oven gas of about 50°C introduced from the indirect gas cooler 5a to about 35°C. The cooled coke oven gas is discharged to the gas refining device 3 . Further, the condensed liquid condensed by cooling in the direct gas cooler 5b accumulates at the bottom of the direct gas cooler 5b together with the sprayed water in which the impurities are dissolved. Most of the accumulated condensed water and sprayed water are collected as recovered water D, cooled, and directly recycled as sprayed water for the gas cooler 5b. In addition, the COG contact refrigerant 41 of the direct gas cooler 5b that cools the recovered water D is cooled in the heat exchanger 42 by natural cold water having a temperature lower than that of the coke oven gas, for example, seawater pumped up from the sea, and is directly gas It is redispersed in the cooler 5b. Also, the recovered water C that has not been recycled is collected in the decanter 6 .

As described above, natural cold water having a lower temperature than coke oven gas, such as seawater, is used as the refrigerant for cooling the COG contact refrigerant 41 of the indirect gas cooler 5a and the COG contact refrigerant 41 of the direct gas cooler 5b. there is Therefore, the temperature of the coke oven gas after the cooling treatment by the gas cooling device 2 (the indirect gas cooler 5a and the direct gas cooler 5b) is about 35°C, and does not fall below the temperature of seawater.

The decanter 6 collects the recovered water A to C from the dry main 4, the indirect gas cooler 5a, and the direct gas cooler 5b, as described above. The recovered waters A to C are separated into a tar mixture containing a large amount of tar and ammonia water (water containing an ammonia component). The amount of ammonia water necessary for cooling the coke oven gas in the dry main 4 is recycled as spray water, as described above, and the rest is discarded after being detoxified by the waste water treatment facility. Tar is recovered, for example, as a by-product.

Although not shown, the coke oven gas cooled by the dry main 4, the indirect gas cooler 5a, and the direct gas cooler 5b is appropriately sucked and pressurized by a discharge device such as a blower on the way, and the gas is purified. It is discharged to the device 3. Also, although not shown, an electrostatic precipitator for removing tar mist, a naphthalene scrubber for removing naphthalene, and the like are appropriately arranged in the route before the air is introduced to the gas purification device 3 .

The gas refining device 3 includes a desulfurization device 7 for desulfurization, an ammonia absorption device 8 for denitrification, and a gas oil absorption device 9 for recovering gas oil as a by-product. In order to comply with environmental regulations, the desulfurization device 7, the ammonia absorption device 8, and the light oil absorption device 9 of the gas refinery device 3 remove sulfur compounds and nitrogen compounds contained in the coke oven gas discharged from the gas cooling device 2, respectively. , and light oil removal. The removed coke oven gas is appropriately reused. The order of arrangement of the desulfurization device 7, the ammonia absorption device 8, and the light oil absorption device 9 is appropriately changed depending on the purpose of refining.

Here, the inventor of the present invention is searching for a method for effectively reducing the concentration of sulfur compounds and nitrogen compounds in the coke oven gas before being introduced into the gas purification device 3. It was found that the sulfur compounds and nitrogen compounds contained in the coke oven gas can be effectively removed by further cooling the coke oven gas and appropriately treating impurities in the recovered water recovered during cooling.

FIG. 2 shows the results of a coke oven gas cooling experiment conducted by the inventor. As shown in FIG. 2, the coke oven gas (black squares, black circles) cooled to 35 ° C. on the gas cooler outlet side is further cooled to 6 ° C. by an indirect cooler (slanted hatched squares, diagonally hatched circles). , ammonia (NH ₃ ) concentration from 14 g/Nm ³ to 6 g/Nm ³ (removal rate of about 57%), hydrogen sulfide (H ₂ S) concentration from 9 g/Nm ³ to 6 g/Nm ³ (removal rate of about 33 %)Diminished. These decreases in concentration are considered to be due to condensation of impurities (ammonia, hydrogen sulfide) due to cooling.
The inventor also conducted a cooling experiment with a direct cooler. When the coke oven gas (black squares, black circles) is cooled to 6° C. by a direct cooler, ammonia and hydrogen sulfide are removed by about 96% and about 94%, respectively, and the ammonia and hydrogen sulfide concentrations are 0.00. It was confirmed that it decreased to 5 g/Nm ³ (white squares, white circles). In the case of cooling by a direct cooler, it is considered that not only the impurities were condensed and removed, but also the impurities were dissolved and removed in the added water.

In the coke oven gas treatment apparatus of the present invention, as shown in FIGS. 3 to 9 below, at least one of nitrogen compounds and sulfur compounds, which are impurities contained in the recovered water, is removed from part or all of the recovered water. Equipped with an impurity removal device for removing the impurities, the recovered water after removing the impurities is reintroduced into the coke oven gas or discharged out of the system. Remove nitrogen compounds and sulfur compounds contained in the coke oven gas introduced to the gas purification device 3 on the downstream side by the impurity removal device, and perform desulfurization processing, denitrification processing, etc. within the range of the processing capacity of the gas purification device 3 can fit in. Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
3 to 6 are diagrams showing part of an example of the configuration of the coke oven gas treatment apparatus 10 according to the first embodiment of the present invention. The gas purifying device 3 on the downstream side has the same configuration as the gas purifying device 3 of the conventional coke oven gas treatment device 1 described above, so its illustration is omitted.

The coke oven gas treatment apparatus 10 of the first embodiment is based on the above knowledge that the hydrogen sulfide (H ₂ S) concentration and ammonia (NH ₃ ) in the coke oven gas are reduced by cooling the coke oven gas. , is constructed. The difference from the conventional coke oven gas treatment apparatus 1 is that a chiller type cooler 15 (chiller type direct cooler 15b or chiller type indirect cooler 15a) is added downstream of the gas cooler 5 of the gas cooling device 2. there is Here, the chiller-type cooler 15 includes a heat exchanger 42x for cooling the COG contact refrigerant 41 that cools the coke oven gas. ) is used to cool the COG contact refrigerant 41 . The heat exchanger 42x uses, for example, a cooler (not shown) using a heat pump or the like. The heat exchange refrigerant 43 is cooled by a cooler to a temperature lower than seawater, which is cold water in nature (for example, 5° C. or less). The exchanger 42x has a cooling capacity to cool the coke oven gas to a temperature (25° C. or lower) lower than that of seawater, which is cold water in nature. The heat exchanger 42x desirably has a cooling adjustment capability to cool the coke oven gas to an arbitrary temperature (for example, 10° C. to 25° C.) lower than seawater, which is cold water in nature.
The configuration of the coke oven gas treatment apparatus 10 of the first embodiment, which is different from the conventional coke oven gas treatment apparatus 1, will be described below with reference to FIGS. 3 to 6. FIG.

FIG. 3 is a configuration diagram when the chiller-type cooler 15 is a chiller-type direct cooler (direct gas cooler) 15b. As shown in FIG. 3, the coke oven gas discharged from the direct gas cooler 5b is introduced to the chiller-type direct cooler 15b, cooled, and then discharged to the gas refining device 3. The chiller-type direct cooler 15b uses the heat exchange refrigerant 43 cooled by the cooler instead of seawater in the heat exchanger 42x, and the separation tank 16 separates the recovered water E into a tar mixture and ammonia water. It has the same configuration as the direct gas cooler 5b except that it is separated into two. Since the heat exchange process is performed by the heat exchange refrigerant 43 cooled by the cooler, the sprayed water (COG contact refrigerant 41) has a lower temperature (5° C. to 20° C.) than the seawater temperature (approximately 35° C.). Due to the use of cold spray water, the coke oven gas is cooled to a temperature lower than the seawater temperature, eg, 10°C to 25°C. By this cooling treatment, the sulfur compounds and nitrogen compounds in the coke oven gas can be condensed or dissolved in the spray water and recovered as recovered water E.

The recovered water E is separated by the separation tank 16 into a tar mixture containing a large amount of tar and ammonia water. The tar mixture is collected in the decanter 6, and the ammonia water is recycled as spray water. An impurity removing device 11 is provided in a path for circulating the ammonia water as spray water. The impurity removal device 11 removes impurities (nitrogen compounds, sulfur compounds) from the recycled water E, and returns the water E after the impurity removal process to the circulation path. Although not shown, part of the tar in the tar mixture collected in the separation tank 16 is appropriately added to the spray water of the chiller-type direct cooler 15b. In the chiller-type direct cooler 15b, the naphthalene and tar condensed as the coke oven gas (COG) is cooled are dissolved to prevent them from adhering and clogging the interior of the device.

The impurity removal device 11 is, for example, a distillation column. Nitrogen compounds and sulfur compounds are removed from the recovered water E by distilling the recovered water E in the distillation column. The distilled water E is returned to the circulation path, cooled by the heat exchanger 42x, and then reused as spray water by the chiller-type direct cooler 15b. On the other hand, the removed nitrogen compounds and sulfur compounds are introduced into the combustion furnace 12, where SO ₂ , N ₂ , H ₂ O, etc. are subjected to combustion treatment or other discharge treatment to the outside of the system. For example, detoxified _N2 , _H2O may be vented from _the stack and _SO2 may be recovered as sulfuric acid ( _H2SO4 ) or gypsum ( _CaSO4 ). Note that the impurity removal device 11 is not limited to the distillation column described above as long as it can remove impurities. For example, impurities may be separated and removed by using an aeration chamber or the like in which a gas body such as air or COG is used for aeration.

FIG. 4 shows a modification of the coke oven gas treatment apparatus 10 using a chiller type direct cooler 15b. In this modification, at least part of the recovered water E subjected to impurity removal processing in the impurity removal device 11 is returned to the decanter 6 or discharged outside the system.

According to the coke oven gas treatment apparatus 10 (using the chiller-type direct cooler 15b) of the first embodiment, the chiller-type direct cooler 15b moves sulfur compounds and nitrogen compounds in the coke oven gas into the recovered water E, and removes impurities. It can be removed from the collected water E by the removing device 11 . Since the sulfur compounds and nitrogen compounds removed from the recovered water E are not returned to the coke oven gas, the concentration of sulfur compounds and nitrogen compounds in the coke oven gas discharged from the outlet side of the gas cooling device 2 to the gas purification device 3 can be reduced.

FIG. 5 is a configuration diagram when the chiller type cooler 15 is a chiller type indirect cooler (indirect gas cooler) 15a. As shown in FIG. 5 , the gas cooling device 2 has a discharge treatment device 17 for discharging the recovered water F from the gas cooling device 2 instead of the impurity removal device 11 .
The coke oven gas discharged from the direct gas cooler 5b is introduced to the chiller-type indirect cooler 15a, cooled, and then discharged to the gas refining device 3. In the heat exchanger 42x, the heat exchange refrigerant 43 cooled by the cooler uses cooling water (COG contact refrigerant 41) that has been heat-exchanged to be lower than the seawater temperature. It has the same configuration as 5a. Since the low-temperature circulating water heat-exchanged by the heat exchanger 42x is used, the coke oven gas is cooled to a temperature lower than the seawater temperature, for example, 10°C to 25°C. By this cooling treatment, sulfur compounds and nitrogen compounds are condensed from the coke oven gas and recovered as recovered water F. By cooling to a temperature lower than the seawater temperature, sulfur compounds and nitrogen compounds in the coke oven gas can be effectively removed.

The recovered water F recovered in the chiller-type indirect cooler 15a is discharged after impurities are removed by the discharge treatment device 17 or the like. The exhaust treatment device 17 is, for example, a combustion furnace. The recovered water F is sent to a combustion furnace, and after the impurities in the recovered water F are burned and rendered harmless, the recovered water F is exhausted from the stack together with the evaporated water vapor. Specifically, unlike the above-described chiller-type direct cooler 15b, the exhaust treatment device 17 does not perform a distillation process, but performs a combustion decomposition process using a combustion furnace. Among SO ₂ , N ₂ , and H ₂ O generated by the combustion decomposition process, SO ₂ that requires exhaust gas treatment is separately used as a raw material for sulfuric acid production, or is disposed of after being neutralized.

FIG. 6 shows a modification of the coke oven gas treatment apparatus 10 using a chiller type indirect cooler 15a. In this modification, the recovered water F recovered in the chiller type indirect cooler 15 a is returned to the decanter 6 . An impurity removal device 11 is disposed on the route returning to the decanter 6, and sulfur compounds and nitrogen compounds in the recovered water F are removed by the impurity removal device 11. FIG. The removed sulfur compounds and nitrogen compounds are appropriately discharged and discharged out of the system.

According to the coke oven gas treatment apparatus 10 (chiller type direct cooler 15b, chiller type indirect cooler 15a) of the first embodiment, the chiller type cooler 15 is provided downstream of the gas cooler 5 to lower the coke oven gas. Cooling to temperature can reduce the amount of sulfur and nitrogen compounds in the coke oven gas. As a result, the concentration of sulfur compounds and the concentration of nitrogen compounds (H ₂ S concentration, NH ₃ concentration, HCN concentration, etc.) in the coke oven gas discharged from the outlet side of the gas cooling device 2 to the gas purification device 3 are reduced. , the concentration can be set within the processing capacity of the downstream gas purifier 3, and the downstream gas purifier 3 can be used as it is without additional installation. Therefore, in coke ovens, using inferior coal as coking coal does not pose a problem. Although it is necessary to add the chiller type cooler 15 and the impurity remover 11, the burden of equipment investment can be suppressed more than the additional installation of the gas purifier 3. The coke oven gas treatment apparatus 10 may be configured to reduce the concentration of sulfur compounds and nitrogen compounds in the coke oven gas discharged to the gas refining apparatus 3 by providing the chiller type cooler 15 . The apparatus and method for treating the sulfur compounds and nitrogen compounds removed by the impurity removal apparatus 11 and the exhaust treatment apparatus 17 are not limited to those described above, and can be appropriately changed according to the purpose.

Although not shown, the gas cooling device 2 of the coke oven gas treatment device 10 can also be configured with a temperature measuring device provided on the outlet side of the chiller type cooler 15 (see temperature measuring device 21 described later). . By measuring the temperature of the coke oven gas discharged from the chiller type cooler 15, H ₂ in the coke oven gas can be determined based on the graph (Fig. 2) showing the relationship between the cooling temperature of the coke oven gas and the concentration of impurities. S concentration and _NH3 concentration can be estimated.

(Second embodiment)
FIG. 7 is a diagram showing an example of the overall configuration of a coke oven gas treatment apparatus 20 according to a second embodiment of the present invention. 7 shows a case where the chiller type cooler 15 is the chiller type direct cooler 15b. The illustration of the case where the chiller type cooler 15 is the chiller type indirect cooler 15a is omitted, but the case where the chiller type cooler 15 is the chiller type indirect cooler 15a also has the same configuration as will be described later. and illustration are omitted.

The coke oven gas treatment apparatus 20 of the second embodiment and the coke oven gas treatment apparatus for implementing the coke oven gas treatment method of the present invention are different from the coke oven gas treatment apparatus 10 of the first embodiment in that H ₂ S A concentration measuring device 23 and an NH ₃ concentration measuring device 25 are provided. The coke oven gas treatment system 20 also includes a temperature control system 44 . The H ₂ S concentration measuring device 23 is provided on the inlet side or the outlet side of the desulfurization device 7 to measure the H ₂ S concentration introduced or exhausted from the desulfurization device 7 . The NH ₃ concentration measuring device 25 is provided on the inlet side or the outlet side of the ammonia absorbing device 8 and measures the NH ₃ concentration introduced or exhausted from the ammonia absorbing device 8 . The temperature control device 44 is a control device that controls the cooling temperature of the coke oven gas by the chiller cooler 15 based on the measured values measured by the H ₂ S concentration measuring device 23 and the NH ₃ concentration measuring device 25 .

In the coke oven gas treatment method, based on the measured value of the H ₂ S concentration measured by the H ₂ S concentration measuring device 23 and the measured value of the NH ₃ concentration measured by the NH ₃ concentration measuring device 25, the chiller on the most downstream side The cooling temperature of the coke oven gas in the formula cooler 15 is controlled. In the coke oven gas treatment device 20, the temperature control device 44 measures the H ₂ S concentration measured by the H ₂ S concentration measuring device 23 and the NH ₃ concentration measured by the NH ₃ concentration measuring device 25. Based on, the cooling temperature of the coke oven gas in the chiller type cooler 15, which is the cooler on the most downstream side, is controlled. The cooling temperature of the coke oven gas is controlled, for example, by temperature control of the heat exchange refrigerant 43 of the cooler.

Specifically, one or both of the H ₂ S concentration in the coke oven gas exhausted from the desulfurization device 7 and the NH ₃ concentration in the coke oven gas exhausted from the ammonia absorber 8 is below the environmental regulation value, for example. For example, the cooling temperature by the heat exchange refrigerant 43 of the chiller cooler 15 is controlled so that the temperature of the coke oven gas on the outlet side of the chiller cooler 15 is lowered when the operation control value determined based on is exceeded. do. By lowering the temperature of the coke oven gas on the outlet side of the chiller cooler 15 , more sulfur compounds and nitrogen compounds in the coke oven gas can be removed inside the chiller cooler 15 . By increasing the removal amount of sulfur compounds and nitrogen compounds, the amount of sulfur compounds and nitrogen compounds introduced into the gas purification device 3 can be reduced, and the H ₂ S concentration exhausted from the desulfurization device 7 and the ammonia absorption device NH ₃ concentration exhausted from 8 can be kept low. In addition, in the above configuration, as shown in FIG. 4, a configuration including a temperature measuring device 21 may be employed. The temperature measuring device 21 is provided on the outlet side of the chiller-type cooler 15 (chiller-type direct cooler 15 b ) and measures the temperature of the coke oven gas discharged from the chiller-type cooler 15 . By providing the temperature measuring device 21 for measuring the temperature of the coke oven gas at the outlet of the actual chiller type cooler 15, the temperature change of the coke oven gas can be monitored.

According to the coke oven gas treatment apparatus 20 and the coke oven gas treatment method of the second embodiment, the coke oven gas in the chiller cooler 15 is cooled based on the measured values of the H ₂ S concentration and the NH ₃ concentration. Since the conditions are controlled, power consumption due to excessive cooling can be suppressed. When the H ₂ S concentration measuring device 23 and the NH ₃ concentration measuring device 25 are provided on the inlet side of the desulfurization device 7 and the inlet side of the ammonia absorption device 8, respectively, H ₂ S introduced into the desulfurization device 7 concentration, the NH ₃ concentration introduced into the ammonia absorber 8 can be measured. Based on these measured values, the temperature control device 44 controls the amount of sulfur compounds and nitrogen compounds in the coke oven gas introduced to the gas purification device 3 to be within the processing capacity of the gas purification device 3. In addition, the cooling conditions of the coke oven gas on the outlet side of the chiller type cooler 15 can be controlled.

Further, when the H ₂ S concentration measuring device 23 and the NH ₃ concentration measuring device 25 are provided on the exit side of the desulfurization device 7 and the exit side of the ammonia absorption device 8, respectively, the H ₂ exhausted from the desulfurization device 7 By measuring the S concentration and the NH ₃ concentration exhausted from the ammonia absorber 8, it is possible to obtain, for example, the difference from the operation control value, which is a guideline for operation. Based on this difference, the cooling conditions for the coke oven gas can be efficiently managed. In addition, the H ₂ S concentration measuring device 23 and the NH ₃ concentration measuring device 25 are provided downstream of the desulfurization device 7 and the ammonia absorption device 8, respectively, to measure the values of the components of the coking coal carbonized in the coke oven and changes in value due to deterioration of each device (the desulfurization device 7 and the ammonia absorption device 8).

The H ₂ S concentration measuring device 23 and the NH ₃ concentration measuring device 25 may be provided on both the inlet side and the outlet side of the desulfurization device 7 and the ammonia absorption device 8, respectively. By measuring the H ₂ S concentration of the coke oven gas on the inlet side and the outlet side of the desulfurizer 7, the desulfurization rate of the desulfurizer 7 can be derived. Further, by measuring the NH ₃ concentration of the coke oven gas on the inlet side and the outlet side of the ammonia absorber 8, the denitrification rate of the ammonia absorber 8 can be derived. Based on the desulfurization rate and the denitrification rate, it is possible to grasp the processing capacity of the desulfurization device 7 and the ammonia absorption device 8 accompanying facility deterioration. The temperature control device 44 can perform temperature control commensurate with the grasped processing capacity.

In the coke oven gas treatment apparatus 20 described above, the configuration includes both the device for measuring the H ₂ S concentration and the device for measuring the NH ₃ concentration, but the configuration includes only one of the measuring devices. and the cooling temperature of the coke oven gas in the chiller cooler 15 may be controlled based on only one of them.

(Third Embodiment)
FIG. 8 is a diagram showing an example of the overall configuration of a coke oven gas treatment apparatus 30 according to a third embodiment of the present invention. While contemplating means for reducing the concentration of nitrogen compounds and sulfur compounds in the coke oven gas introduced to the gas refining device 3, the present inventors have come up with a coke oven gas treatment device according to the third embodiment described below. 30 configurations were conceived.
As shown in FIG. 8, unlike the coke oven gas treatment apparatus 20 of the second embodiment, the gas cooling apparatus 2 of the coke oven gas treatment apparatus 30 of the third embodiment does not include the chiller type cooler 15. An impurity removing device 11 is provided in a route through which the recovered water A to D of the conventional coke oven gas treatment device 1 is recycled, or in a branched route. The configuration of the impurity removal device 11 and the combustion furnace 12 and the processing by these devices are the same as those of the coke oven gas treatment device 10 of the first embodiment, so the description is omitted.

Impurities are condensed in the recovered waters A to D. As shown in FIG. 8, in the direct gas cooler 5b, the impurity removal device 11 is provided in a branch path that branches off from the circulation path of the recovered water D that is circulated as spray water and joins again. A part of the recovered water to be recycled is extracted from the circulation path, and after nitrogen compounds and sulfur compounds are removed by the impurity removal device 11, it is returned to the circulation path. It is also possible to provide the impurity removing device 11 in the circulation path without providing the branch path, and to remove the nitrogen compounds and the sulfur compounds from all of the recovered water to be recycled.

FIG. 9 is an explanatory diagram illustrating another example of the coke oven gas treatment apparatus 30 according to the third embodiment of the present invention. In addition, in FIG. 9, the positions where the impurity removal devices 13a, 13b, and 13c are provided are schematically illustrated, and the illustration of the combustion furnace 12 is omitted.
In the third embodiment shown in FIG. 8, the impurity removal device 11 is provided directly in the circulation path of the recovered water D of the gas cooler 5b. Any configuration may be employed as long as it is provided in the circulation path of the recovered water A to D recovered in the device 2 . For example, like the impurity removal devices 13a, 13b, and 13c shown in FIG. A split flow path, a split flow path provided in the path where the recovered water B recovered in the indirect gas cooler 5a is collected in the decanter 6, and a route provided in the route where recovered water C recovered in the direct gas cooler 5b is collected in the decanter 6. A portion of the recovered water A to C may be provided in the branch path to remove nitrogen compounds and sulfur compounds. Further, the impurity removers 13a, 13b, and 13c may be provided on the path collected in the decanter 6 without providing a branch path, like the impurity remover 11 of the coke oven gas treatment apparatus 30. FIG.

According to the coke oven gas treatment apparatus 30 of the third embodiment and its modification, unlike the conventional coke oven gas treatment apparatus 1 in which the removal of sulfur compounds and nitrogen compounds is entrusted to the gas purification device 3 on the downstream side, , sulfur compounds and nitrogen compounds can be removed in the gas cooling device 2 on the upstream side. Specifically, the impurity removal devices 11, 13a, 13b, and 13c remove nitrogen compounds and sulfur compounds, which are impurities contained in the recovered waters A to D, from part or all of the recovered waters A to D. , it is possible to reduce the amount of sulfur compounds and nitrogen compounds in the spray water that is put into the coke oven gas (recycled). As a result, the concentration of sulfur compounds and the concentration of nitrogen compounds (H ₂ S concentration, NH ₃ concentration, HCN concentration, etc.) in the coke oven gas exhausted from the outlet side of the gas cooling device 2 are reduced, and the downstream side gas It is possible to make the concentration within the range of the processing capacity of the refiner 3, and it is possible to use the gas as it is without adding an additional downstream gas refiner 3. Therefore, using inferior coal for coking coal does not pose a problem. Although it is necessary to add the impurity removal device 11 and the like, the burden of facility investment can be suppressed more than the additional installation of the gas purification device 3 . At least one of the impurity removal devices 11, 13a, 13b, and 13c may be added. Further, the impurity removal devices 13a, 13b, and 13c may be configured such that the recovered water A to C to be removed are collected at one location and treated by one impurity removal device. Although not shown, some or all of the recovered water A to D may be discharged outside the system by the above-described discharge treatment device 17 or the like.

As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings. According to each of the above-described embodiments, the sulfur compounds (H ₂ S concentration, etc.) in the coke oven gas on the downstream side of the gas cooling device 2 ) and nitrogen compounds (such as _NH3 concentration and HCN concentration) could be reduced. In addition, this invention is not limited to embodiment mentioned above. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 10, 20, 30... Coke oven gas treatment apparatus, 2... Gas cooling apparatus, 3... Gas purification apparatus, 4... Dry main, 5... Gas cooler, 6... Decanter, 7... Desulfurization apparatus, 8... Ammonia absorption apparatus , 9... light oil absorption device, 11, 13... impurity removal device, 15... chiller type cooler, 16... separation tank, 17... discharge treatment device, 21... temperature measurement device, 23... _H2S concentration measurement device, 25... NH ₃ concentration measuring device, A to F... recovered water, 41... COG contact refrigerant, 42, 42x... heat exchanger, 43... heat exchange refrigerant, 44... temperature control device

Claims (7)

A coke oven gas treatment apparatus for recovering coke oven gas generated during carbonization of coal and removing impurities,
a gas cooling device for cooling the coke oven gas;
A gas purifying device provided downstream of the gas cooling device and performing purification processing of the coke oven gas after the cooling treatment;
a controller ;
The gas cooling device includes a chiller-type cooler provided on the most downstream side thereof, and a part or all of the recovered water recovered from the gas path, and removes nitrogen compounds and sulfur compounds, which are impurities contained in the recovered water. an impurity removal device for removing at least one of the
The gas purifier has one or both of a desulfurization device and a denitrification device,
The gas cooling device or the gas purifying device includes an H ₂ S concentration measuring device for measuring the H ₂ S concentration in the coke oven gas downstream of the chiller type cooler, and a coke oven downstream of the chiller type cooler. Having one or both of an NH ₃ concentration measuring device for measuring the NH ₃ concentration in the gas ,
The control device cools the coke oven gas by the chiller cooler based on one or both of the measured value measured by the H ₂ S concentration measuring device and the measured value measured by the NH ₃ concentration measuring device. A coke oven gas treatment apparatus for controlling temperature . 2. A coke oven gas treatment apparatus according to claim 1, wherein the recovered water passing through the impurity removal device is introduced into the coke oven gas. 3. The coke oven gas treatment apparatus according to claim 1, wherein said impurity removal device removes said impurities contained in water recovered from said chiller type cooler. The chiller type cooler is a chiller type indirect cooler,
4. The gas cooling device according to claim 3, wherein the gas cooling device has a discharge treatment device for discharging the recovered water recovered from the chiller-type indirect cooler from the gas cooling device instead of the impurity removal device. coke oven gas treatment equipment. The control of the cooling temperature of the coke oven gas by the chiller type cooler is
5. The coke oven gas treatment apparatus according to any one of claims 1 to 4 , wherein the temperature of a heat exchange refrigerant used in said chiller type cooler is adjusted. A coke oven gas treatment method using the coke oven gas treatment apparatus according to claim 3 or 4. Controlling the cooling temperature of the coke oven gas by the chiller cooler,
7. The coke oven gas treatment method according to claim 6 , wherein the temperature of a heat exchange refrigerant used in the chiller type cooler is adjusted.

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