KR102484968B1 - Method and apparatus for treating cokes oven gas - Google Patents

Abstract

The present invention includes a coke oven gas purification step of absorbing hydrogen sulfide and ammonia contained in the coke oven gas; Claus process step of recovering sulfur from the acid gas containing the absorbed hydrogen sulfide and ammonia; A tail gas purification step of purifying the tail gas discharged from the clause process to generate purified tail gas and acid gas; and mixing the purified tail gas with the purified coke oven gas. According to the present invention, by reducing the load of the flow rate of crude COG purification facilities, there is an effect of reducing costs such as investment and operating costs consumed in the COG purification process, and by reducing the concentration of hydrogen sulfide and carbon dioxide in crude COG, COG purification during hydrogen sulfide cleaning It has the effect of improving efficiency. In addition, the amount of sulfur dioxide in crude COG is reduced, improving COG purification efficiency and reducing the load due to sulfur, thereby reducing the load in the wastewater treatment process.

Description

Coke oven gas processing device and processing method {METHOD AND APPARATUS FOR TREATING COKES OVEN GAS}

The present invention relates to a coke oven gas processing device and processing method, and more particularly, to a coke oven gas processing device and processing method including a purification process of tail gas generated in a clause process. .

In the coke oven for producing coke, Coke Oven Gas (COG) is generated during the carbonization process, and this COG gas is a major by-product gas of the steelmaking process used for power generation or fuel in steelworks. When COG gas is generated in a coke oven, it contains impurities such as hydrogen sulfide (H ₂ S), ammonia (NH ₃ ) and BTX, so a purification process is absolutely necessary before use.

Among them, hydrogen sulfide is not only a major material that causes corrosion of COG transport pipes, but also contains sulfur, which is an emission control material, and must be removed. In addition, ammonia not only causes corrosion, but also reacts with carbon dioxide (CO ₂ ) in COG or other by-product gases to precipitate in the form of ammonium carbonate in the transport pipe, causing pipe blockage.

Hydrogen sulfide is generally removed using ammonia water or sodium hydroxide (NaOH) solution as an absorbent, and ammonia is separately removed using soft water as an absorbent, and hydrogen sulfide and hydrogen sulfide and A process for simultaneously removing ammonia with high efficiency has also been proposed (Patent registration number: 10-1839225).

1 schematically shows a commonly used COG treatment method. Referring to FIG. 1, crude COG passes through a gas cooler 10, an electric precipitator 20, and a blower 30, and hydrogen sulfide and ammonia are absorbed in the hydrogen sulfide and ammonia scrubber 40, and in the BTX scrubber 50 BTX is absorbed and then excreted. The absorbent liquid absorbing hydrogen sulfide and ammonia in the hydrogen sulfide and ammonia scrubber 40 is sent to the absorbent liquid regenerator 70 to be regenerated, and the regenerated absorbent liquid is reused in the hydrogen sulfide and ammonia scrubber 40. The acid gas generated in the absorption liquid regeneration device 70 is sent to the Claus process device 60, sulfur is recovered through the Claus process, and the generated tail gas is reintroduced to the COG treatment process. The tail gas discharged through the clause process is mixed with crude COG, and contains higher concentrations of hydrogen sulfide, sulfur dioxide (SO ₂ ) and carbon dioxide than crude COG. In particular, since carbon dioxide competes with the hydrogen sulfide removal of the absorbent used in the hydrogen sulfide scrubber, it becomes a major factor in reducing the hydrogen sulfide removal performance.

On the other hand, the flow rate of the tail gas discharged through the clause process is about 10% of the total crude COG, the hydrogen sulfide concentration is more than twice, the carbon dioxide concentration is 5 to 10 times, and the sulfur dioxide concentration is about 0.1 to 0.5%, which is an impurity of crude COG. There is a problem in that the concentration of is increased, resulting in an increase in the amount of COG purification equipment and impurities, and a decrease in purification efficiency.

The present invention has been made in view of the above circumstances, and is intended to provide a coke oven gas treatment device and treatment method capable of reducing the flow rate and concentration of impurities in a COG refinery facility, and improving purification efficiency.

According to one aspect of the present invention, the coke oven gas purification step of absorbing hydrogen sulfide and ammonia contained in the coke oven gas; an absorption liquid regeneration step of regenerating the absorption liquid which has absorbed the hydrogen sulfide and ammonia; Claus process step of recovering sulfur from the acid gas generated in the absorption liquid regeneration step; A tail gas purification step of purifying the tail gas discharged from the clause process to generate purified tail gas and acid gas; and mixing the purified tail gas with the purified coke oven gas.

The acid gas generated in the tail gas purification step may be reintroduced into the clause process.

The temperature of the acid gas generated in the absorption liquid regeneration step may be 60 °C or higher.

The tail gas purification step may include hydrogenating the tail gas; Quenching the hydrogenated tail gas; and absorbing the acidic gas included in the quenched tail gas using an absorbent containing amine.

A solution condensed in the step of quenching the hydrogenated tail gas may be used as an absorption liquid for absorbing ammonia in the step of refining the coke oven gas.

Hydrogenating the tail gas may be performed by heating the tail gas to 220 to 280° C. and introducing hydrogen or liquefied natural gas.

Quenching the hydrogenated tail gas may be performed at a temperature of 40° C. or less.

In the step of absorbing the acid gas contained in the quenched tail gas using an aqueous amine solution, an absorbent liquid containing amine is introduced into the absorption tower to absorb the acid gas contained in the gas, and the absorbent liquid in which the acid gas has been absorbed is regenerated discharging to a tower; Discharging the regenerated absorbent liquid by separating the acid gas contained in the absorbent liquid in which the acid gas has been absorbed into a gas phase in a regeneration tower; and transferring the regenerated absorption liquid to the absorption tower.

The solution purged in the regeneration tower may be input to an absorption liquid regeneration step of regenerating the absorption liquid that has absorbed the hydrogen sulfide and ammonia.

According to another aspect of the present invention, a hydrogen sulfide scrubber tower for absorbing hydrogen sulfide in coke oven gas by reacting coke oven gas with ammonia water and an ammonia scrubber for absorbing ammonia by reacting the hydrogen sulfide removed coke oven gas with soft water. a coke oven gas purification device; an absorbent liquid regeneration device for regenerating the absorbent liquid that has absorbed the hydrogen sulfide and ammonia; Clause process device for recovering sulfur from the acid gas generated in the absorption liquid regeneration device; and a tail gas purifier for purifying the tail gas discharged from the clause process unit and supplying the refined coke oven gas to the coke oven gas purifier.

The tail gas purification device includes a tail gas hydrogenation treatment device; a quenching device for quenching the hydrogenated tail gas; and an acid gas absorber for absorbing the acid gas included in the quenched tail gas using an absorbent containing amine.

The condensate produced in the quenching device may be supplied to the ammonia scrubber.

The acid gas absorption device absorbs acid gas into an amine-containing absorption liquid, and an absorption tower for discharging the acid gas-absorbed absorption liquid to a regeneration tower and separating acid gas from the absorption liquid discharged from the absorption tower into the gas phase and discharging it A regeneration tower may be included.

The purified tail gas discharged from the upper part of the absorption tower may be supplied to the purified coke oven gas, and the acid gas discharged from the upper part of the regeneration tower may be supplied to the clause process equipment.

The solution purged in the regeneration tower may be introduced into the absorption liquid regeneration device.

According to the present invention, by reducing the load of the flow rate of crude COG purification facilities, there is an effect of reducing costs such as investment and operating costs consumed in the COG purification process, and by reducing the concentration of hydrogen sulfide and carbon dioxide in crude COG, COG purification during hydrogen sulfide cleaning It has the effect of improving efficiency. In addition, the amount of sulfur dioxide in crude COG is reduced, improving COG purification efficiency and reducing the load due to sulfur, thereby reducing the load in the wastewater treatment process.

1 schematically shows a commonly used COG treatment method.
2 schematically illustrates a COG processing method according to an embodiment of the present invention.
3 schematically shows a tail gas purification method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to various examples. However, the embodiments of the present invention may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to a coke oven gas treatment device and treatment method, and FIG. 2 schematically shows a COG treatment method according to an embodiment of the present invention. Hereinafter, the present invention will be described in more detail with reference to FIG. 2 .

According to one aspect of the present invention, the coke oven gas purification step of absorbing hydrogen sulfide and ammonia contained in the coke oven gas; Claus process step of recovering the sulfur contained in the acid gas containing the absorbed hydrogen sulfide and ammonia; A tail gas purification step of purifying the tail gas discharged from the clause process to generate purified tail gas and acid gas; and mixing the purified tail gas with the purified coke oven gas.

The coke oven gas purification step is a step of absorbing hydrogen sulfide and ammonia contained in coke oven gas, and the coke oven gas purification step includes a hydrogen sulfide scrubber tower for absorbing hydrogen sulfide of coke oven gas by reacting coke oven gas and ammonia water, and the hydrogen sulfide It can be carried out through a coke oven gas purification device including an ammonia scrubber that absorbs ammonia by reacting the removed coke oven gas with soft water.

The coke oven gas purification apparatus 1000 may include a gas cooler 10, an electric precipitator 20, and a blower 30, and a hydrogen sulfide scrubber tower that absorbs hydrogen sulfide from the coke oven gas by reacting coke oven gas with ammonia water. And hydrogen sulfide and ammonia are removed in the ammonia scrubber 40 that absorbs ammonia by reacting the coke oven gas from which hydrogen sulfide has been removed with soft water, and the absorbent liquid containing hydrogen sulfide and ammonia is regenerated in the absorbent liquid regenerator 70. At this time, acid gas is generated. Meanwhile, the cleaned coke oven gas is discharged to the outside of the coke oven gas purifier after BTX is removed in the BTX washing tower 50.

The acid gas generated in the absorbent liquid regeneration device 70 passes through the Claus process step 60, and sulfur is removed in the form of sulfur. The Claus device 60 and process applied in the present invention can be performed using known devices and methods, and the Claus device and process are widely known to those skilled in the art, so here the Claus process and A detailed description of the device will be omitted.

이하의 온도로 냉각될 경우, 암모니아와 황화수소가 반응하여 황화수소암모늄((NH₄)HS)을 석출 시키거나 암모니아와 이산화탄소가 반응하여 탄산암모늄 형태로 석출될 수 있으며, 이에 따라, 배관 막힘 등의 문제가 발생할 수 있다. 따라서, 흡수액 재생장치(70)에서 발생되는 산성가스의 온도를 60

이상으로 유지하는 것이 바람직하다. On the other hand, the acid gas generated in the absorption liquid regeneration device 70 is hydrogen sulfide (H ₂ S), ammonia (NH ₃ ), carbon dioxide (CO ₂ ) And since it contains water vapor (H ₂ O) as the main component, 60

When cooled to a temperature below, ammonia and hydrogen sulfide may react to precipitate ammonium hydrogen sulfide ((NH ₄ )HS) or ammonia and carbon dioxide may react to precipitate in the form of ammonium carbonate, thereby causing problems such as clogging of pipes may occur. Therefore, the temperature of the acid gas generated in the absorption liquid regeneration device 70 is 60

It is desirable to keep above.

The tail gas recovered and discharged from the Clause process contains higher concentrations of hydrogen sulfide, sulfur dioxide and carbon dioxide than crude COG. , can also lower the purification efficiency. In the present invention, it is possible to reduce the load of the COG purification facility and improve the efficiency by recovering sulfur in the clause process and independently purifying the discharged tail gas.

Preferably, the tail gas discharged from the clause process may be introduced into the tail gas refiner 80 to generate refined tail gas and acid gas. At this time, the refined tail gas is mixed with the refined coke oven gas in the coke oven gas purification device 1000, and the refined tail gas is maintained similar to the coke oven gas properties when there is no tail gas purification facility. No changes to the process utilizing coke oven gas are required. In addition, through the load of the treatment flow, there is an effect of reducing costs such as investment and operating costs consumed in the COG purification process, and the reduction of hydrogen sulfide and carbon dioxide concentrations in crude COG improves COG purification efficiency during hydrogen sulfide cleaning. In addition, the amount of sulfur dioxide in crude COG is reduced, improving COG purification efficiency and reducing the load due to sulfur, thereby reducing the load in the wastewater treatment process.

On the other hand, refined coke oven gas and refined tail gas may be discharged to the outside after burning in an incinerator, but are used as raw materials for producing carbonates (CaCO ₃ , MgCO ₃ , NaHCO ₃ , Na ₂ CO ₃ , etc.), It can be used for various purposes, such as using only carbon dioxide after separation and purification, using it for neutralizing an alkali solution, or using it as a raw material gas for producing chemicals using carbon dioxide. In addition, since the acid gas discharged from the tail gas purification step contains hydrogen sulfide and carbon dioxide, it can be put into the clause process again and the above process can be repeated.

FIG. 3 schematically shows a tail gas purification method according to an embodiment of the present invention. Hereinafter, referring to FIG. 3, a tail gas purification device and a purification step will be described in more detail.

The tail gas purification step is a step of purifying the tail gas discharged from the Claus process device in the tail gas purifier 2000 to generate refined tail gas and acid gas. As described above, the purified tail gas is purified The acid gas is then reintroduced to the Claus process.

The tail gas purifier includes a tail gas hydroprocessing device 200, a quenching device 300 for quenching the hydrogenated tail gas, and an absorption liquid containing amine for acid gas included in the quenched tail gas. It includes an acid gas absorbing device 400 for absorbing by using.

In the tail gas hydroprocessing device, the tail gas is heated to 220 to 280°C, and hydrogen or liquefied natural gas is introduced to convert sulfur dioxide, carbon disulfide (CS ₂ ), COS, and S present in the tail gas into H ₂ S form. let it In order to reach a temperature of 220 to 280 ° C., which is a preferred reaction temperature, the tail gas is heated using a heating means such as a burner or heater 110, and H ₂ required for the reaction is supplied from the outside or by supplying LNG to obtain H It can also be decomposed into ₂ and supplied to the hydrogenation reactor 120.

The hydrogenated tail gas is sent to the quench tower 130 of the quenching device 300 to be quenched, and the tail gas must be supplied to the acid gas absorber 400 at a temperature of 40 ° C or less to obtain high Since the H ₂ S removal efficiency can be achieved, it is preferable to adjust the temperature of the tail gas to 40° C. or less. Accordingly, since most of the condensate produced is dissolved in water and a small amount of H ₂ S, it can be used as an absorption liquid for removing ammonia from coke oven gas, so it is supplied to the ammonia scrubber of the coke oven gas purifier to purify coke oven gas can be reused in

Meanwhile, the acid gas included in the quenched tail gas is supplied to the acid gas absorption device 400 using a blower 140 or the like, and the acid gas included in the quenched tail gas is absorbed using an aqueous amine solution. step is performed. Blowers may be disposed before and after the hydrogenation reactor.

The acid gas absorber 400 absorbs acid gas into an amine-containing absorption liquid, and the absorption tower 150 discharges the acid gas-absorbed absorption liquid to a regeneration tower, and the acid gas from the absorption liquid discharged from the absorption tower is converted into a gas phase. It includes a regeneration tower 160 that separates and discharges into. An aqueous amine solution may be used as the absorption liquid, and MDEA of 20 to 55 wt % may be preferably used as the absorption liquid.

In the regeneration tower 160, a certain amount of purge is required to prevent concentration of highly volatile substances. Since the purged solution contains hydrogen sulfide and carbon dioxide, it is supplied to and treated in a regeneration process of an absorption liquid used in coke oven gas purification.

Meanwhile, the purified tail gas discharged from the top of the absorption tower 150 is mixed with the purified coke oven gas as described above. If not mixed with refined coke oven gas, tail gas may be discharged to the outside after burning in an incinerator, but it is used as a raw material for carbonates (CaCO ₃ , MgCO ₃ , NaHCO ₃ , Na ₂ CO ₃ , etc.), It can be used for various purposes, such as using only carbon dioxide after separation and purification, using it for neutralizing an alkali solution, or using it as a raw material gas for producing chemicals using carbon dioxide. In addition, since the acid gas discharged from the top of the regeneration tower contains hydrogen sulfide and carbon dioxide, it can be put into the clause process again and the above process can be repeated. Unlike the acid gas from the coke oven refining process, this acid gas does not contain ammonia, so there is no risk of precipitation of highly corrosive substances such as ammonium hydrogen sulfide ((NH ₄ )HS). It can be supplied through the Claus process. In addition, the material of the acid gas supply pipe can be made of general steel or stainless steel, not Ni-Cr high corrosion resistance steel.

Table 1 below shows the composition of the tail gas treated according to the tail gas purifier and method of the present invention.

Concentration (Vol.) hydrogen sulfide < 50ppm carbon dioxide 20% carbon monoxide 500 ppm hydrogen 3% methane 1500 ppm nitrogen 72% moisture 5%

As can be seen from Table 1, when the refined tail gas is mixed with the refined coke oven gas, the properties of the existing refined coke oven gas remain similar, so there is no need to change the existing process using the coke oven gas. . In addition, through the load of the treatment flow, there is an effect of reducing costs such as investment and operating costs consumed in the COG purification process, and the reduction of hydrogen sulfide and carbon dioxide concentrations in crude COG improves COG purification efficiency during hydrogen sulfide cleaning. In addition, the amount of sulfur dioxide in crude COG is reduced, improving COG purification efficiency and reducing the load due to sulfur, thereby reducing the load in the wastewater treatment process.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention described in the claims. It will be obvious to those skilled in the art.

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Claims (15)

A coke oven gas purification step of absorbing hydrogen sulfide and ammonia contained in the coke oven gas;
an absorption liquid regeneration step of regenerating the absorption liquid which has absorbed the hydrogen sulfide and ammonia;
Claus process step of recovering sulfur from the acid gas generated in the absorption liquid regeneration step;
A tail gas purification step of purifying the tail gas discharged from the clause process to generate purified tail gas and acid gas; and
mixing the purified tail gas with purified coke oven gas;
The tail gas purification step may include hydrogenating the tail gas; Quenching the hydrogenated tail gas; and absorbing the acid gas included in the quenched tail gas using an amine-containing absorption liquid.
According to claim 1,
A method of treating coke oven gas by reintroducing the acid gas generated in the tail gas purification step to the clause process.
According to claim 1,
The temperature of the acid gas generated in the absorption liquid regeneration step is 60 ℃ or more, a method of treating coke oven gas.
delete According to claim 1,
The solution condensed in the step of quenching the hydrogenated tail gas is used as an absorption liquid for absorbing ammonia in the coke oven gas purification step.
According to claim 1,
The step of hydrogenating the tail gas is performed by heating the tail gas to 220 to 280 ° C and introducing hydrogen or liquefied natural gas.
According to claim 1,
The step of quenching the hydrogenated tail gas is performed at a temperature of 40 ° C or less, a method of treating coke oven gas.
According to claim 1,
In the step of absorbing the acid gas contained in the quenched tail gas using an aqueous amine solution, an absorbent liquid containing amine is introduced into the absorption tower to absorb the acid gas contained in the gas, and the absorbent liquid in which the acid gas has been absorbed is regenerated discharging to a tower; Discharging the regenerated absorbent liquid by separating the acid gas contained in the absorbent liquid in which the acid gas has been absorbed into a gas phase in a regeneration tower; and transferring the regenerated absorption liquid to the absorption tower.
According to claim 8,
The solution purged in the regeneration tower is input to the absorption liquid regeneration step of regenerating the absorption liquid that has absorbed the hydrogen sulfide and ammonia.
A hydrogen sulfide scrubber tower that absorbs hydrogen sulfide from coke oven gas by reacting coke oven gas with ammonia water and an ammonia scrubber that absorbs ammonia by reacting the hydrogen sulfide-removed coke oven gas with soft water Coke oven gas purification device including;
an absorbent liquid regeneration device for regenerating the absorbent liquid that has absorbed the hydrogen sulfide and ammonia;
Clause process device for recovering sulfur from the acid gas generated in the absorption liquid regeneration device; and
A tail gas purifying device for purifying the tail gas discharged from the clause process device and supplying the refined coke oven gas to the coke oven gas purifying device;
The tail gas purification device includes a tail gas hydrogenation treatment device; A quenching device for quenching the hydrogenated tail gas; and an acid gas absorber for absorbing the acid gas contained in the quenched tail gas using an absorbent containing amine.
delete According to claim 10,
The condensate produced in the quenching device is supplied to the ammonia scrubber.
According to claim 10,
The acid gas absorption device absorbs acid gas into an amine-containing absorption liquid, and an absorption tower for discharging the acid gas-absorbed absorption liquid to a regeneration tower and separating acid gas from the absorption liquid discharged from the absorption tower into the gas phase and discharging it A coke oven gas treatment device comprising a regeneration tower.
According to claim 13,
The purified tail gas discharged from the upper part of the absorption tower is supplied to the purified coke oven gas, and the acid gas discharged from the upper part of the regeneration tower is supplied to the clause process equipment.
According to claim 13,
The solution purged in the regeneration tower is introduced into the absorption liquid regeneration device.

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