KR20050029924A - An apparatus for purifying coke oven gas with co2 separator - Google Patents

Abstract

To provide a coke oven gas purification apparatus with CO2 collector for collecting CO2 that hinders collection of hydrogen sulfate, thereby lowering concentration of CO2 in coke oven gas to improve a collection ratio of hydrogen sulfate and suppressing precipitation of carbonate due to reaction of CO2 and sodium hydroxide to prevent closing of an ammonium distillation column and a desulfurizer catalyst reactor. In an apparatus comprising a hydrogen sulfate collection column(102), an ammonia collection column(120), an ammonia concentration column(106) and an ammonia distillation column(110) to purify coke oven gas, the apparatus for purifying coke oven gas with CO2 collector comprises a CO2 collection part(10) comprising a CO2 collector(12) installed in front of the hydrogen sulfate collection column and a potassium hydroxide tank(14) communicated with the CO2 collector to supply a potassium hydroxide solution into the CO2 collector so that CO2 in coke oven gas is collected; and a potassium hydroxide treatment part(30) for collecting CO2 from the CO2 collector and treating the potassium hydroxide solution discharged, wherein the potassium hydroxide treatment part comprises a potassium hydrogen carbonate tank(32) connected to the CO2 collector; a temperature increasing machine(34) connected to the potassium hydrogen carbonate tank; and a potassium carbonate tank(36) and a potassium hydroxide tank(38) connected to the temperature increasing machine, and a separator(42) communicated with the potassium carbonate tank and the potassium hydroxide tank.

Description

AN APPARATUS FOR PURIFYING COKE OVEN GAS WITH CO2 SEPARATOR}

The present invention relates to an apparatus for purifying coke oven gas (COG) generated during the process of manufacturing coke by distilling coal in a coke oven, and more particularly, by removing carbon dioxide from the COG to improve the hydrogen sulfide capture rate in the COG The present invention relates to a coke oven gas purifier having an improved carbon dioxide capture device to prevent the ammonia distillation column and the desulfurization catalytic catalytic reactor from closing.

Generally, coke oven gas generated when coke is produced by coking coal in coke oven contains various components. Among them, ammonia, hydrogen sulfide, and hydrogen cyanide cause corrosion or closure of gas pipe, and COG is used as fuel. If used, it causes pollution, so it should be used below a certain concentration.

Conventionally, in order to purify coke oven gas, first, ammonia in COG is removed and absorbed into a sulfuric acid solution, or decomposed in a cracking furnace and then released into the air. The method of decomposing double ammonia in a cracking furnace has a problem of causing pollution by including sulfur oxides in the gas discharged from the cracking furnace when ammonia and hydrogen sulfide are mixed.

In addition, hydrogen sulfide and hydrogen cyanide are more difficult to remove and cause pollution than ammonia, and many processes have been developed to remove them.

That is, as shown in FIG. 1, in the hydrogen sulfide collection tower 102, ordination (ammonia water) that collects hydrogen sulfide, ammonia, carbon dioxide, and the like from COG is stored in the ordination tank 104, and the ordination tank is 104 is supplied to the ammonia concentration tower 106 through the pipe 104a.

The ordination water supplied to the ammonia concentration tower 104 as described above is distilled by steam supplied through the steam pipe 106a installed under the ammonia concentration tower 106 to generate acid gas. The acidic gas (hydrogen sulfide steam, ammonia vapor, etc.) is supplied to the desulfurization facility catalytic reactor 108 through a pipe 106b.

As described above, the acid gas supplied to the desulfurization facility catalytic reactor 108 passes through the catalyst layer 108a in the desulfurization facility catalytic reactor 108 and is discharged to a post process to recover pure sulfur.

In addition, the concentrated ammonia discharged from the lower portion of the ammonia concentration tower 40 is partially supplied to the hydrogen sulfide collection tower 102 through the pipe 106c, and used to collect hydrogen sulfide in the COG, and part of the branch pipe 106d. It is supplied to the ammonia distillation column 110 through the distillation by steam supplied from the lower portion of the ammonia distillation column (110).

The acid gas distilled as described above is supplied to the middle of the ammonia concentration tower 106 by the pipe 110a, and the desulfurization facility catalytic reactor through the pipe 106b together with the acid gas generated in the ammonia concentration tower 106. The desorption water supplied to 108 and lowered to the lower portion of the ammonia distillation column 110 is sent to the ammonia collection tower 120 through a pipe 110b and used for collecting ammonia in COG.

In addition, the ammonia collection tower 120 is supplied with soft water for ammonia collection. In the ammonia collection tower 120, while COG escapes from the lower part of the ammonia collection tower 120 to the upper part, The ammonia is collected and COG from which the ammonia has been removed is finally transferred to a gas holder (not shown) through a post process.

In the hydrogen sulfide collection tower 102, hydrogen sulfide is collected by the untreated water supplied from the ammonia concentration tower 106 and the ordination supplied from the ammonia collection tower 120 while the COG escapes from the lower portion to the upper portion thereof. The hydrogen sulfide-collected liquid exits from the lower portion of the hydrogen sulfide collection tower 102 and is stored in the ordination tank 104 through the pipe 102a to continuously purify COG.

At this time, hydrogen sulfide and ammonia are respectively collected by the dehydrogenated water, de-anhydrated water, and soft water in the hydrogen sulfide collecting tower 102 and the ammonia collecting tower 120, and a large amount of carbon dioxide contained in the COG is the hydrogen sulfide collecting tower 102. Causes inhibition of hydrogen sulfide capture from COG.

That is, when hydrogen sulfide and ammonia are collected from COG by desorption, desorption, and soft water, carbon dioxide is also collected, thereby reducing the amount of hydrogen sulphide by desorption, desorption, and soft water.

On the other hand, the carbon dioxide collected by the ordination, etc. as described above is supplied to the ordination tank 104 and introduced into the ammonia distillation tower 110, wherein the carbon dioxide introduced into the ammonia distillation tower 110 as described above is the ammonia distillation tower 110 It reacts with the caustic soda charged in the precipitates of carbonate.

2A and 2B illustrate the bubble cap 114 and the tray 112 closed by the structure of the tray 112 and the carbonate, and as the precipitation of the carbonate is repeated as described above, the bubble cap 114 and When the tray 112 is closed, the operation of the coke oven gas purification device is stopped by closing the passage of the ordination and steam of the ammonia distillation tower 110, so that the ammonia distillation tower 110 is dismantled and the bubble cap 114 installed therein. And carbonates attached to the tray 112 had to be removed.

In addition, since the acid gas supplied to the desulfurization facility catalytic reactor 108 contains a part of carbonate and is discharged, there is a problem in that the pores of the catalyst filled in the catalyst layer 108a are closed and smooth operation is impossible.

The present invention is to solve the conventional problems as described above, by collecting the carbon dioxide that inhibits the collection of hydrogen sulfide in advance to lower the concentration in the COG to improve the collection rate of hydrogen sulfide, carbon dioxide and carbon dioxide and ammonia distillation column in COG It is an object of the present invention to provide a coke oven gas purifier having an improved carbon dioxide capture device so as to suppress precipitation of carbonate by reaction of caustic soda supplied to the ammonia distillation tower and the desulfurization facility catalytic reactor.

In order to achieve the above object, the present invention comprises a carbon dioxide collector installed in front of the hydrogen sulfide collecting tower, and a potassium hydroxide tank in communication with the carbon dioxide collector to supply a potassium hydroxide solution to the carbon dioxide collector to collect the carbon dioxide in the COG A carbon dioxide collector; And a potassium hydroxide treatment unit for capturing carbon dioxide from the carbon dioxide collector and treating the discharged potassium hydroxide solution.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 shows a coke oven gas purification device 1 having a carbon dioxide capture device according to the present invention, the structure of which is as follows.

The coke oven gas purification device 1 including the carbon dioxide collecting device according to the present invention includes a carbon dioxide collecting unit 10 and a potassium hydroxide treatment unit 30. First, the carbon dioxide collecting unit 10 will be described below. Same as

As shown in FIG. 3, the carbon dioxide collector 10 includes a carbon dioxide collector 12 and a potassium hydroxide tank 14, which is disposed at the front end of the hydrogen sulfide collector tower 102. The potassium hydroxide tank 14 is connected by the carbon dioxide collector 12 and the pipe 14a so as to supply potassium hydroxide in the potassium hydroxide tank 14 to the carbon dioxide collector 12.

At this time, the carbon dioxide collector 12 has the same structure as a conventional collection tower having a built-in injection nozzle and the like, potassium hydroxide in the potassium hydroxide tank 14 is not shown, but the carbon dioxide collector 12 by a pump or the like. It is configured to be supplied with.

Next, the structure of the potassium hydroxide treatment unit 30 will be described.

As shown in FIG. 3, the potassium hydroxide treatment unit 30 includes a potassium hydrogen carbonate tank 32 and a temperature increaser 34. The potassium hydrogen carbonate tank 32 includes the carbon dioxide collector 12 and the carbon dioxide collector 12. Connected and configured to store potassium hydroxide which collects carbon dioxide from COG in the carbon dioxide collector 12.

The potassium hydrogen carbonate tank 32 is connected to the potassium carbonate tank 36 by a pipe 34a via a temperature riser 34, and a cooler 44 is installed in the pipe 34a.

In addition, the potassium carbonate tank 36 is connected to the separator 42 by piping, and the calcium hydroxide tank 38 is also connected to the separator by piping, in which the separator 42 is connected to the potassium hydroxide tank 14. Is connected by a pipe.

On the other hand, the pipes connecting the respective tanks described above are not shown, but a conventional pump and valves are installed to supply potassium hydroxide, potassium hydrogen carbonate, potassium carbonate, etc. to the tanks connected by the pipe.

Referring to the operation of the coke oven gas purification device 1 having a carbon dioxide capture device according to the present invention configured as described above are as follows.

As shown in FIG. 3, COG is introduced into the carbon dioxide collector 12 through the COG inlet pipe 12a installed at the lower portion of the carbon dioxide collector 12 and exits to the upper portion thereof to the hydrogen sulfide collecting tower 102. The potassium hydroxide solution from the potassium hydroxide tank 14 is supplied to the upper side of the carbon dioxide collector 12 through a pipe 14a by a pump (not shown) during the inflow.

At this time, the potassium hydroxide solution supplied to the carbon dioxide collector 12 is sprayed from the inner upper portion of the carbon dioxide collector 12 is in direct contact with the COG introduced into the carbon dioxide collector 12.

That is, the potassium hydroxide solution absorbs carbon dioxide and becomes a potassium hydrogen carbonate solution. The chemical reaction is as follows.

KOH + CO ₂ → KHCO ₃

Accordingly, the precipitation of the carbonate due to the reaction of the caustic soda supplied to the carbon dioxide and the ammonia distillation column 110 is suppressed, the bubble cap and the tray installed inside the ammonia distillation column 110, and the catalyst layer 108a of the desulfurization facility catalytic reactor 108 Since the pores of the catalyst filled in) are not closed, smooth operation is possible.

The potassium hydrogen carbonate solution generated as described above is introduced into the potassium hydrogen carbonate tank 32 through the pipe 12b, and introduced into the temperature riser 34 through the discharge pipe 32a of the potassium hydrogen carbonate tank 32 to exchange heat. It heats up to 190 degreeC by heat exchange with a medium.

At this time, the carbon dioxide contained in the potassium hydrogen carbonate solution starts to slowly separate at 100 ℃ and completely separated at 190 ℃ to produce a potassium carbonate solution, the chemical reaction formula is as follows.

2KHCO ₃ → K ₂ CO ₃ + CO ₂ + H ₂ O

Thereafter, the separated carbon dioxide, potassium carbonate, and water are introduced into the potassium carbonate tank 36 through a pipe 34a, wherein the separated water and carbon dioxide are cooled by heat exchange with the heat medium in the cooler 44. And, the carbon dioxide is included in the COG introduced into and discharged from the ammonia collection tower 120 outlet COG pipe (120a) through the discharge pipe (44a).

Then, the condensed water condensed by the cooling is introduced into the potassium carbonate tank 36 through the drain pipe 44b installed on the discharge pipe 44a at the rear end of the cooler 44, and the potassium carbonate separated from the carbon dioxide is piped as described above. It flows into the potassium carbonate tank 36 via 34a.

Meanwhile, the calcium hydroxide tank 38 is supplied with calcium hydroxide from the outside through a supply pipe 38b in a sol state, and the potassium carbonate and calcium hydroxide tank discharged from the potassium carbonate tank 36 through the discharge pipe 36a. In (38), the calcium hydroxide in the sol state is discharged through the discharge pipe (38a) and flows into the separator (42).

At this time, the potassium carbonate and calcium hydroxide is mixed reaction to produce calcium carbonate and potassium hydroxide, respectively, the chemical reaction formula is as follows.

K ₂ CO ₃ + Ca (OH) _2- > 2KOH + CaCO ₃ ↓

Therefore, in the separator 42, calcium carbonate precipitates under the separator 42 due to the difference in specific gravity between potassium carbonate and calcium hydroxide, and the precipitated calcium carbonate is treated in the wastewater through the discharge pipe 42a in a sol state. It is sent to a facility (not shown) and used as a mineral (calcium ion) replenisher for aerobic bacteria.

In addition, the potassium hydroxide solution separated in the separator 42 as described above is circulated and supplied into the potassium hydroxide tank 14 through the supply pipe 42b connecting the separator 42 and the potassium hydroxide tank 14 and again. Used to absorb carbon dioxide in COG.

At this time, insufficient potassium hydroxide in the potassium hydroxide tank 38 is supplied from the outside into the potassium hydroxide tank 38 as a potassium hydroxide solution through the supply pipe 14b.

The liquid level of each device and tank described above may be controlled by a conventional liquid level control device, and the temperature riser 34 and the cooler 44 may be heated and cooled by a heat exchange medium and a conventional temperature control device.

That is, since the carbon dioxide collector 12 is supplied with potassium hydroxide as described above, it only selectively collects carbon dioxide and does not absorb hydrogen sulfide or ammonia because the potassium hydroxide is in a standard state (0 ° C., 1 atm), normal temperature, and normal pressure. Because the reaction does not occur with hydrogen sulfide or ammonia, but only by a high temperature and high pressure atmosphere or a catalyst, the reaction does not occur at the temperature of the inflow COG (about 25 to 30 ° C.) and pressure (1200 to 1800 mmH ₂ O). to be.

(Example)

The supply flow rate of COG supplied into the carbon dioxide collector 12 is 5000 Nm ³ / hr, and the carbon dioxide collector 12 is supplied with a 60% potassium hydroxide solution at a supply amount of 6 m ³ / hr and contacted with COG. Is shown in Table 1 below.

Table 1

As shown in Table 1, it can be seen that hydrogen sulfide is almost not collected by potassium hydroxide and only carbon dioxide is selectively collected.

Therefore, by selectively collecting only carbon dioxide by the carbon dioxide collector 12, the hydrogen sulfide collection rate in the hydrogen sulfide collecting tower 102 can be significantly increased.

While the invention has been shown and described with respect to particular embodiments, it will be appreciated that the invention can be varied and modified without departing from the spirit or scope of the invention as set forth in the claims below. It will be appreciated that those skilled in the art can easily know.

As described above, according to the present invention, by collecting the carbon dioxide in front of the hydrogen sulfide collecting tower 102 by the carbon dioxide collector 12, the hydrogen sulfide in the COG from which the carbon dioxide is removed from the hydrogen sulfide collecting tower 102 is collected. By increasing the hydrogen sulfide capture rate significantly, there is an effect of suppressing the emission of sulfur oxides as a pollutant.

In addition, the precipitation of carbonate by the reaction of carbon dioxide and carbon dioxide in the COG and the caustic soda supplied to the ammonia distillation column 110 is suppressed, and a bubble cap and a tray installed inside the ammonia distillation column 110, and the catalytic desulfurization reactor 108 Since the pores of the catalyst filled in the catalyst layer 108a of the catalyst are not closed, there is an effect of enabling smooth operation.

1 is a schematic view showing a conventional coke oven gas purification device;

Figure 2 shows a tray and a bubble cap installed in the ammonia distillation column of the conventional coke oven gas purification device,

(a) is a perspective view of a tray,

(b) is a cross-sectional view of the tray and the bubble cap;

Figure 3 is a schematic diagram showing a coke oven gas purification apparatus having a carbon dioxide capture device according to the present invention.

Explanation of symbols on the main parts of the drawings

10 ..... CO2 collector 12 ..... CO2 collector

14 ..... Potassium hydroxide tank 30 ..... Potassium hydroxide treatment

32 ..... Potassium hydrogen carbonate tank 34 .....

36 ..... potassium carbonate tank 38 ..... calcium hydroxide tank

42 ..... Separator 44 ..... Chiller

102 ..... Hydrogen sulfide collection tower 104 ..... Ordination tank

106 ..... Ammonia Concentration Tower 110 ..... Ammonia Distillation Column

120 ..... Ammonia Collection Tower

Claims (2)

In the apparatus for purifying coke oven gas, including the hydrogen sulfide collection tower 102, ammonia collection tower 120, ammonia concentration tower 106, ammonia distillation tower 110, A carbon dioxide collector 12 installed at the front end of the hydrogen sulfide collecting tower 102 and a potassium hydroxide tank 14 communicating with the carbon dioxide collector 12 to supply a potassium hydroxide solution to the carbon dioxide collector 12, thereby providing a COG. A carbon dioxide collecting unit 10 which collects carbon dioxide inside; And A potassium hydroxide processing unit 30 for collecting carbon dioxide from the carbon dioxide collector 12 and treating the discharged potassium hydroxide solution; Coke oven gas purification apparatus having a carbon dioxide capture device, characterized in that it comprises a. The method of claim 1, wherein the potassium hydroxide treatment unit 30 A potassium hydrogen carbonate tank (32) connected to the carbon dioxide collector (12) to store a potassium hydroxide solution that collects carbon dioxide from COG; A temperature increaser 34 connected to the potassium hydrogen carbonate tank 32 and heating the potassium hydroxide solution in which carbon dioxide is collected; And A potassium carbonate tank 36 and a calcium hydroxide tank 38 connected to the temperature riser 34, and a separator 42 connected to communicate with the potassium carbonate tank 36 and the calcium hydroxide tank 38; Coke oven gas purification apparatus having a carbon dioxide capture device, characterized in that it comprises a.