JPS63166414A - Treatment method for coke oven gas - Google Patents

Abstract

PURPOSE:To increase desulfurizing efficiency by cooling down coke oven gas down to 35 deg.C or higher, wet desulfurizing the same with alkaline solution, then deaminating and feeding back vapor containing NH3 generated in the deaminating process to the front of a wet desulfurizing device. CONSTITUTION:Coke oven gas is cooled down by a cooling device 1, and at that time the temperature at an outlet is set at approximately >=35 deg.C. Then, the coke oven gas contacts alkaline solution in a wet desulfurizing device 5 and wet desulfurized. Further, the coke oven gas is contacted with ammonium phosphate aqueous solution in an NH3 absorption tower 6 of the deamination process C to absorb NH3, and absorbing solution is regenerated in a stripper 8, while substances guided out of a tower top are rectified by a fractionater feed tank 9 and a fractionater 10 to cool down NH3 gas and recovered into a liquid ammonia tank 11. NH3 and vapor containing acid gas are fed back to the front of a wet desulfurizing device 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cooling process (A) for cooling coke oven gas generated from a coke oven, and a method for treating the coke oven gas that has passed through the cooling process (A) with an alkaline liquid. Improvement of a coke oven gas processing method consisting of a desulfurization process (B) in which wet desulfurization is carried out by contact, and a desulfurization process (C) in which ammonia is recovered by desulfurizing the coke oven gas that has undergone the desulfurization process (B). In particular, the present invention relates to a method for improving the desulfurization efficiency of a wet desulfurization apparatus in the desulfurization process (B).

Conventional technology The coke oven gas generated by carbonization of coal is about 6
0% is hydrogen, and the rest mainly consists of hydrocarbons such as methane and ethane, and some carbon monoxide, carbon dioxide, and oxygen, but apart from these components, hydrogen sulfide, hydrogen cyanide, and ammonia Contains impurities. These impurities.

When coke oven gas is used as fuel gas, it becomes a harmful gas during combustion and is emitted into the atmosphere, which can also cause damage to combustion equipment.Also, its constituent components (hydrogen, etc.) must be separated and recovered from coke oven gas. Sometimes it shortens the life of adsorbents and catalysts. Therefore, removal of the above-mentioned impurities in coke oven gas is essential for effective utilization of coke oven gas.

One of the effective methods for desulfurization (removal of sulfur compounds) and desulfurization (removal of ammonia) of coke oven gas is to wet desulfurize the coke oven gas that has undergone the cooling process (A) by contacting it with an alkaline solution. process (B);
A process is known that combines the desulfurization process (B) with a desulfurization process (C) in which ammonia is recovered by desulfurizing the coke oven gas.

A typical example of the desulfurization process (B) is the so-called FUMAKS process, and a typical example of the desulfurization process (C) is the so-called Forasum (PH) process.
O3AM) process.

FIG. 4 is a process diagram showing an example of a conventional method for treating coke oven gas using such a bonding process.

In FIG. 4, A is a cooling process (A). In this cooling process (A), coke oven gas generated from a coke oven is cooled by a gas cooling device (1). The gas cooling device (1) in this example consists of a primary cooler (1a) and a direct cooler (lb).

In Figure 4, B is the desulfurization process (B), this JI[
In the E process (B), the above cooling process (A)
The coke oven gas that has passed through is subjected to wet desulfurization by contact with an alkaline liquid in a wet desulfurization device (5). Wet desulfurization equipment (
5) is a desulfurization absorption tower (5a) and a reburst tower (5a) in this example.
In the desulfurization absorption tower (5a) consisting of 5b), hydrogen sulfide, hydrogen cyanide and ammonia contained in the coke oven gas are mutually effectively used, and the catalyst (picric acid)
In the presence of , hydrogen sulfide is converted to colloidal sulfur, and the sulfur and hydrogen cyanide formed are further converted to harmless perthiocyanate. The first-stage reaction is a Fumax process, and the second-stage reaction is a Rodax process, and the desulfurization absorption tower (5a) fulfills both of these functions with one device.

In FIG. 4, (2) is a blower 1, (3) is a naphthalene scrubber, and (4) is an electrostatic precipitator. Cooling process (A
) and the desulfurization process (B), the naphthalene scrubber (3) removes the naphthalene contained in the coke oven gas by absorbing oil.
The electric precipitator (4) can remove tar mist and absorbed oil mist.

In FIG. 4, C is a desulfurization process (C). In this desulfurization process (C), the coke oven gas that has undergone the desulfurization process (B) is desulfurized and ammonia is recovered.

The main equipment in this desulfurization process (C) is an ammonia absorber (6), a stripper (8) and a fractionator (10), that is, the main equipment derived from the wet desulfurization device (5) of the desulfurization process (B). The coke oven gas is introduced into the ammonia absorber t ) is supplied to the stripper (8) via the contactor (7) and distilled while blowing in steam, and the product derived from the top of the stripper (8) is It is supplied to the fractionator (10) via the fractionator feed tank (9) and rectified under pressure while blowing in steam, and the ammonia gas derived from the top of the column is cooled and sent to the liquid ammonium tank. Collect at (11).

Then, the cooling process (A) and the desulfurization process (B)
In the conventional process consisting of the cooling process (A) and the desulfurization process (C), the direct cooler (l
The outlet temperature of the coke oven gas derived from b) has conventionally been set at 27 to 33°C. Gas cooling condenses and removes impurities in the gas (especially naphthalene), so the lower the cooling temperature, the better.Moreover, the lower the temperature, the smaller the volume, which is advantageous for suction and subsequent equipment such as the blower (2). - If the temperature is set too low, there is a risk that the direct cooler (1b) will be clogged with naphthalene, so the above temperature is adopted in consideration of this balance.

In addition, in the conventional process consisting of the cooling process (A), desulfurization process (B), and desulfurization process (C), the contactor (7) in the desulfurization process (C)
When the vapor (L) and the vapor (b) of the fractionator feed tank (9) contain a large amount of acidic gases (COz, H2, S, HCN), they react with ammonia and become salts. Since there is a risk that the ammonia may precipitate and cause problems such as clogging, it was continuously fed back to the ammonia absorber (6). Also, the oil purge (C) of the fractionator (10)
) is also continuously fitted with an ammonia absorber (6) in the same way to prevent oil content from affecting the product ammonia quality.
I had given feedback before.

In addition, the product ammonia vapor (d) at the start of the ammonium removal process (C), and the vapor in the ammonium tank (11) (
e), residual pressure purge (f) at the time of lorry shipment, etc., were returned in batches as necessary, for example, before the primary cooler (la) of the cooling process (A).

Problems to be Solved by the Invention However, when a process combining the above-mentioned processes is carried out industrially, the coke oven derived from the desulfurization absorption tower (5a) of the wet desulfurization apparatus (5) of the desulfurization process (B) The HλS concentration in the gas is, for example, 0.2 to 0.0 when the coke oven gas flow rate is 9500 ONrn''/H·tower.
The desulfurization efficiency is approximately 3 g/Nrn', and it is desired to further increase the desulfurization efficiency. Further, it is desired to further improve this process not only from the desulfurization efficiency but also from energy saving and other industrial viewpoints.

In order to meet such demands, the present invention was achieved as a result of intensive studies on improving the above-mentioned process.

Means for Solving the Problems The coke oven gas treatment method of the present invention includes a cooling process (A) for cooling coke oven gas generated from a coke oven.
and a desulfurization process (B) in which the coke oven gas that has undergone the cooling process (A) is wet desulfurized by contacting with an alkaline liquid.
and a desulfurization process (C) in which ammonia is recovered by desulfurizing the coke oven gas that has undergone the desulfurization process (B).
) In the method for treating coke oven gas, the following steps (1) and (2) are carried out, namely: (1) setting the outlet temperature of the coke oven gas derived from the gas cooling device (1) of the cooling process (A) to 35°C or higher; , (feeding back the ammonia-containing vapor or (and) the acid gas-containing vapor in the desulfurization process (C) before the wet desulfurization device (5) in the desulfurization process (B)). It is characterized by the fact that it is carried out.

The present invention will be described in detail below with reference to the drawings as necessary. Note that although some parts overlap with the explanation of the conventional method, we will explain it in detail again.

FIG. 1 is a process diagram showing an example of the coke oven gas treatment method of the present invention.

As mentioned above, the coke oven gas processing method of the present invention includes: A: a cooling process (A) for cooling coke oven gas generated from a coke oven; and B: coke oven gas that has undergone the cooling process (A). Desulfurization process (B) in which wet desulfurization is performed by contact with alkaline liquid
and C: a desulfurization process (C) in which ammonia is recovered by desulfurizing the coke oven gas that has undergone the desulfurization process (B).
).

Process A In FIG. 1, A is a cooling process (A). In this cooling process (A), coke oven gas generated from a coke oven is cooled by a gas cooling device (1). In this example, the gas cooling device (1) consists of a primary cooler (la) and a direct cooler (1b), but depending on the device, the direct cooler (1b) may be omitted.

Process B In Figure 1, B is the desulfurization process (B). In this desulfurization process (B), the coke oven gas that has passed through the cooling process (A) is converted into alkaline liquid in the wet desulfurization equipment (5). wet desulfurization by contact with Wet desulfurization equipment (5)
In this example, the desulfurization absorption tower (5a) and the regeneration tower (5b
), and in the desulfurization absorption tower (5a), hydrogen sulfide, hydrogen cyanide, and ammonia contained in coke oven gas are mutually effectively utilized, and hydrogen sulfide is converted to colloidal sulfur in the presence of a catalyst (picric acid). The sulfur and hydrogen cyanide produced are converted into harmless thiocyanate. The first stage reaction is the Fumax process, and the second stage reaction is the Rodax process.
The desulfurization absorption tower (5a) serves both of these functions in one device.

Hikitan j! Imaginary 1 In Figure 1, (2) is a blower, (3) is a naphthalene scrubber, and (4) is an electrostatic precipitator. Cooling process (A
) and the desulfurization process (B), the naphthalene scrubber (3) removes the naphthalene contained in the coke oven gas by absorbing oil.
The electric precipitator (4) can remove tar mist and absorbed oil mist.

Process C In FIG. 1, C is the Forasum process as a representative example of the de-anxification process (C). In this desulfurization process (C), the coke oven gas that has undergone the desulfurization process (B) is desulfurized and ammonia is recovered.

The main devices in this desulfurization process (C) are an ammonia absorber (6), a stripper (8) and a fractionator (10).

That is, the coke oven gas derived from the wet desulfurization device (5) of the desulfurization process (B) is passed through an ammonia absorber.
(6) and brought into countercurrent contact with an aqueous ammonium phosphate solution to remove ammonia in the gas and derive it as purified coke oven gas, and the ammonia component derived from the ammonia absorber (6). An aqueous solution of ammonium phosphate rich in ammonium phosphate is supplied to a stripper (8) via a contactor (7), where it is distilled while blowing in steam, and the output from the top of the stripper (8) is sent to a fractionator feed tank (9). ) and is supplied to a fractionator (10) to perform rectification under pressure while blowing in steam, and the ammonia gas derived from the top of the column is cooled and collected in a liquid ammonium tank (11).

Isen 1 In the present invention, the following (1) and (2) apply.

■ Setting the outlet temperature of the coke oven gas derived from the gas cooling device (1) in the cooling process (A) to 35°C or higher, ■ Ammonia-containing vapor or (and) acid gas-containing in the desulfurization process (C) Feeding the vapor back to the wet desulfurization device (5) of the desulfurization process (B).

<Improvement ■> First, regarding ■, conventionally the outlet temperature was set at 27 to 33°C, but in the present invention, this was set at 35°C.
The temperature was set as high as above (preferably 35 to 39°C).

With this improvement, the wet desulfurization equipment (
The concentration of free ammonia (free-NH) in the desulfurization absorption liquid in the desulfurization absorption tower (5a) of 5) is, for example, 7.
．． Hz in the coke oven gas derived from the desulfurization absorption tower (5a) increases from 5g/i to 8.2g/i.
The S concentration has been increased from the conventional 0.2 to 0.3 g/Nm'' to 0.1
It decreases to about 3 to 0.19 g/Nrn''.

In addition, even if the outlet temperature is set high in this way, the
When the temperature is about 39°C, there is almost no hindrance to the condensation removal of impurities in the gas (particularly the reduction of naphthalene), and there is almost no disadvantage to suction and subsequent equipment such as the blower (2).

<Improvements ■> Next, regarding ■, conventionally the ammonia-containing vapor or (and) acid gas-containing vapor in the desulfurization process (C), more specifically, the vapor (a) of the contactor (7), the fractionator feed The vapor (b) of the tank (9) and the oil purge (C) of the fluxinator (10) are continuously
(6), but in the present invention, this is fed back before the wet desulfurization device (5) of the desulfurization process (B).

In addition, in the past, the product ammonia vapor (d) at the start of the desulfurization process (C), the vapor (e) in the ammonium tank (11), and the residual pressure purge (f) at the time of lorry shipment were carried out as necessary, for example. However, in the present invention, these vapors or ammonia-containing vapors (g) from purge or other steps are returned to the wet desulfurization equipment of the desulfurization process (B). Feedback was made before (5) or to the cooling process (A).

With this improvement, the wet desulfurization equipment (
The concentration of free ammonia in the desulfurization absorption liquid in the desulfurization absorption tower (5a) of 5) ranges from 7.5gel to 8.0gel, for example.
g/l, and as a result, the H and S concentrations in the coke oven gas derived from the desulfurization absorption tower (5a) are lower than the conventional (7)
0.2-0.3g/Nm” to 0.15-0.22g
/Nrn”.

<Improvements ■ and ■> Then, in the present invention, if both of Items E. The concentration of ammonia increases, for example, from 7.5 g/l to 8.7 g/l, and as a result, the H2, S concentration in the coke oven gas derived from the desulfurization absorption tower (5a) is lower than that of conventional c7) 0. 2
~0.3g/Nnf to 0.08~0.118/Nm1
decrease to a certain extent.

Figure 2 shows the outlet temperature of the coke oven gas derived from the direct cooler (1b) of the gas cooling device (1) in the cooling process (A) and the wet desulfurization device (5) in the desulfurization process (B). It is a graph showing the relationship with the concentration of free ammonia (free-NH3) in the desulfurization absorption liquid in the desulfurization absorption tower (5a).

Thus, it can be seen that as the outlet temperature increases, the concentration of free ammonia in the desulfurization absorption liquid increases almost linearly.

Figure 3 shows the concentration of free ammonia (free -NH5) in the desulfurization absorption liquid in the desulfurization absorption tower (5a) of the wet desulfurization equipment (5) of the desulfurization process (B) and the concentration of free ammonia (free -NH5) in the gas. It is a graph showing the relationship with the concentration of H5).

In this way, under certain temperature conditions, the desulfurization absorption tower (5a)
It can be seen that there is a relationship in which the concentration of free ammonia in the desulfurization absorption liquid increases as the concentration of coke oven gas increases.

In the present invention, as in the above (■), the cooling process (A)
When the outlet temperature of the coke oven gas derived from the gas cooling device (1) of
Since the concentration of free ammonia in the desulfurization absorption liquid increases, the H2, S concentration in the coke oven gas derived from the desulfurization absorption tower (5a) decreases.

In addition, when the ammonia-containing vapor or (and) acidic sulfur-containing vapor in the desulfurization process (C) is fed back before the wet desulfurization device (5) in the desulfurization process (B) as in C U above, the desulfurization process The concentration of 'M-free ammonia in the coke oven gas introduced into the desulfurization absorption tower (5a) of the wet desulfurization equipment (5) of (B) increases, and as a result, the free ammonia in the desulfurization absorption liquid in the desulfurization absorption tower (5a) increases. Since the ammonia concentration increases, H,s1 degrees in the coke oven gas derived from the desulfurization absorption tower (5a) decreases.

If both of the above (1) and (furnace) are implemented, the concentration of free ammonia in the desulfurization absorption liquid in the desulfurization absorption tower (5a) increases, and the H2sH degree in the coke oven gas derived from the desulfurization absorption tower (5a) increases. is reduced to, for example, about 40% of the conventional value.

Example Next, the present invention will be further explained with reference to Examples.

Comparative examples are also shown.

Comparative Example According to the process diagram shown in FIG. 4, coke oven gas generated from a coke oven was cooled, desulfurized and deanized.

The concentration of free ammonia in the coke oven gas at the inlet of the desulfurization absorption tower (5a) is 8.5 g/Nrn" x 130K
Nm" = 1100 Kg/H.

The circulation rate of the desulfurization absorption liquid was set at 2200 m''/H.

The outlet temperature of the coke oven gas derived from the direct cooler (lb) of the gas cooling device (1) in the cooling process (A) was set at 32°C.

From Figure 2, the concentration of free ammonia in the desulfurization absorption liquid is 7
．． It turns out that it is 5g/i.

Furthermore, from FIG. 3, it can be seen that the concentration of free ammonia in the coke oven gas is 8.5 g/Nrn', which corresponds to the concentration of free ammonia in the desulfurization absorption liquid of 7.5 g/41.

The actual value of the concentration of H and S in the coke oven gas derived from the desulfurization absorption tower (5a) was determined at a coke oven gas flow rate of 9500
In the case of 0 Nm3/H, it was 0.2 to 0.33/Nm''.

Example 1 This example shows a case where only the following conditions are adopted.

Similar to the comparative example, coke oven gas generated from a coke oven was cooled, desulfurized, and desulfurized according to the process diagram shown in FIG.

However, the outlet temperature of the coke oven gas derived from the direct cooler (1b) of the gas cooling device (1) in the cooling process (A) was set at 36°C.

Other conditions were the same as in the comparative example.

From FIG. 2, it can be seen that the concentration of 'M-released ammonia in the desulfurization absorption liquid is 8.2 g/l, which is an increase of 0.7 g/l compared to the comparative example.

Furthermore, from FIG. 3, the concentration of M-free ammonia in the coke oven gas is 9.3 g/Nrn'', which corresponds to the concentration of free ammonia in the desulfurization absorption liquid of 8.2 g/l, which is 0% compared to the comparative example. It can be seen that the increase is .8 g/Nm'.

The actual measured value of the concentration of H2S in the coke oven gas derived from the desulfurization absorption tower (5a) is the coke oven gas Ft, &9
5000 Nrn'/Ht7) case, 0.13~0
．． 19 g/N.Example 2 This example shows the case where only the condition (2) was adopted.

The coke oven gas generated from the coke oven was cooled, desulfurized, and desulfurized according to the process diagram shown in FIG.

The outlet temperature of the coke oven gas derived from the direct cooler (1b) of the gas cooling device (1) in the cooling process (A) was set at 32° C. as in the comparative example.

The concentration of free ammonia in the coke oven gas at the inlet of the desulfurization absorption tower (5a), excluding the feedback described below, is 8.5 g/Nm''X 130KNrn' = 11
00Kg/H.

The circulation rate of the desulfurization absorption liquid was set at 2200 rn''/H.

The free ammonia in the vapor (a) of the contactor (7) is 30 Kg/H, the free ammonia in the vapor (b) of the fractionator feed tank (9) is zero, and the oil purge (C The free ammonia in ) is 20Kg/H, and these are (i.e., total 50Kg/H・series x 2 series = 100Kg
/H) and was continuously returned to the front of the desulfurization absorption tower (5a).

Therefore, the free ammonia in the coke oven gas at the inlet of the desulfurization absorption tower (5a) is 1100Kg/H+100
Kg/H = 1200Kg/H, which means 8 in terms of concentration.
．． 28/Nm''. This is 8.5g/Nr in the comparative example.
This is an increase of 0.78/N compared to "n".

From FIG. 3, the concentration of free ammonia in the desulfurization absorption liquid is 8.0 g/l, which corresponds to the concentration of free ammonia in the coke oven gas of 9.2 g/Nm, which is 0.0 g/l compared to the comparative example.
It can be seen that the amount has increased by 5 g/l.

The actual value of the concentration of H and S in the coke oven gas derived from the desulfurization absorption tower (5a) was determined at a coke oven gas flow rate of 9500
0 N go/H, 0.15~0.22°/Nm
"Met.

Example 3 This example shows a case where both the conditions (■) and -α are adopted.

According to the process diagram shown in FIG. 1, coke oven gas generated from a coke oven was cooled, desulfurized, and desulfurized.

The outlet temperature of the coke oven gas derived from the direct cooler (1b) of the gas cooling device (1) in the cooling process (A) was set at 36° C. as in Example 1.

The concentration of free ammonia in the coke oven gas at the inlet of the desulfurization absorption tower (5a) is 8.5 g/Nm" x 130KNm" = 11, excluding the feedback described below.
There was 00Kg/Hte.

The circulation rate of the desulfurization absorption liquid was set at 2200 go/h.

The free ammonia in the vapor (&) of the Huntafter (7) is 30 Kg/H, the free ammonia in the vapor (b) of the fractionator feed tank (9) is zero, and the oil purge (C The free ammonia in ) is 20g/H, which is (i.e. total 50Kg/H・series x 2 series = 100K
g/)I), the same way as in Example 2, the desulfurization absorption tower (5
Returned to before a).

It can be seen that the concentration of free ammonia in the desulfurization absorption liquid is 8.7 g/liter, which is an increase of 1.23/i compared to the comparative example.

The concentration of free ammonia in coke oven gas is 10-0 g
/Nrn' and 1.5g/Nrn'' compared to the comparative example.
You can see that it is rising.

The actual measured value of the concentration of H2S in the coke oven gas derived from the desulfurization absorption tower (5a) is based on the coke oven gas flow rate of 9500
0 Nrn”/H, 0.08 to 0.11 g/N
m'', which was reduced by about 40% compared to the comparative example.

Effects of the Invention In the present invention, (1) changing the outlet temperature of the coke oven gas derived from the gas cooling device (1) of the cooling process (A), or (and), Is) desulfurization process (C)
Ammonia-containing vapor or (and) i!
The desulfurization efficiency of the wet desulfurization apparatus (5) can be significantly increased by simply setting conditions such as changing the feedback destination of the vapor containing the i' gas.

Therefore, the desulfurization process (B) is followed by the desulfurization process (
The coke oven gas that has passed through C) does not contain sulfur compounds and ammonia, reducing the risk of air pollution when this coke oven gas is used as fuel, and it is possible to separate specific gases (such as hydrogen) that make up the coke oven gas. In this case, the life of the adsorbent and catalyst will be extended, and the manufacturing cost will be reduced. Furthermore, the amount of desulfurization catalyst used in the desulfurization process (B) is reduced, and the amount of circulating fluid is also reduced, which is advantageous in terms of operating costs.

In addition, when the condition (a) is adopted, the amount of cooling water used in the gas cooling device (1) can be reduced, and when the condition (a) is adopted, the concentration of free ammonia in the coke oven gas can be reduced. As a result, the production amount of product ammonia (liquid ammonium) in the debasement process (C) increases.

Therefore, it can be said that the present invention has extremely high practicality in industrial applications.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing an example of the coke oven gas treatment method of the present invention. Figure 2 shows the outlet temperature of coke oven gas derived from the direct cooler (lb) of the gas cooling device (1) in the cooling process (A) and the desulfurization absorption in the wet desulfurization device (5) in the desulfurization process (B). It is a graph showing the relationship with the concentration of free ammonia (free-NH3) in the desulfurization absorption liquid in the tower (5a). Figure 3 shows the concentration of free ammonia (free -N H3) in the desulfurization absorption liquid in the desulfurization absorption tower (5a) of the wet desulfurization equipment (5) of the desulfurization process (B) and the concentration of Vi free ammonia (free -N H3) in the gas. 3 is a graph showing the relationship with the concentration of NH3). FIG. 4 is a process diagram showing an example of a conventional method for treating coke oven gas. (A)... Cooling process, (B)... Desulfurization process, (C)... Desulfurization process. (a)...Vapor (a) of contactor (7), (
b)... Vapor in the fractionator feed tank (9), (C)... Oil purge in the fractionator (10), (d)... Product ammonia vapor,
(e)...Vapor in the low liquid tank (11), (f)...
...Residual pressure purge at the time of lorry shipment, (g)...Ammonia-containing vapor from other processes. (1)...Gas cooling device, (1a)...Primary cooler, (1b)...Direct cooler, (2
)...Blower 1 (3)...Naphthalene scrubber, (4)...Electrostatic precipitator, (5)...Wet desulfurization device, (5a)...Desulfurization absorption tower, (5b) ...Regeneration Tower,
(6)... Ammonia absorber 1 (7)... Contactor 1 (8)... Stripper, (9)...
Fractionator feed tank, (10)... Fractionator, (11)... Liquid ammonium tank Patent applicant Kansai Thermal Chemical Co., Ltd. - j j ・ 1 Agent Patent attorney Seibu Oishi 1. :L and - Figure 2 Outlet temperature ("C)

Claims (1)

[Claims] 1. A cooling process (A) for cooling coke oven gas generated from a coke oven, and a desulfurization process (a) for wet desulfurization of the coke oven gas that has undergone the cooling process (A) by contacting it with an alkaline liquid. B) and a desulfurization process (C) in which ammonia is recovered by desulfurizing the coke oven gas that has undergone the desulfurization process (B), in which the following (a) and (b) are carried out. , that is, (
a) Setting the outlet temperature of the coke oven gas derived from the gas cooling device (1) in the cooling process (A) to 35°C or higher; (b) Ammonia-containing vapor or (and) in the desulfurization process (C) A method for treating coke oven gas, comprising: feeding back acidic gas-containing vapor before a wet desulfurization device (5) in a desulfurization process (B). 2. The method according to claim 1, wherein the gas cooling device (1) in the cooling process (A) comprises a primary cooler (1a) or a primary cooler (1a) and a direct cooler (1b). 3. A patent characterized in that the coke oven gas that has undergone the cooling process (A) is guided to the desulfurization process (B) through a blower (2), a naphthalene scrubber (3), and an electrostatic precipitator (4). The method according to claim 1. 4. The method according to claim 1, wherein the wet desulfurization device (5) in the desulfurization process (B) comprises a desulfurization absorption tower (5a) and a regeneration tower (5b). 5. In the desulfurization process (C), the coke oven gas derived from the wet desulfurization device (5) of the desulfurization process (B) is introduced into the ammonia absorber (6) and brought into contact with an ammonium phosphate aqueous solution, thereby reducing the gas content. At the same time, ammonia is removed from the ammonia absorber (6) and the ammonium phosphate aqueous solution rich in ammonia component is passed through a contactor (6).
7) to a stripper (8) to perform distillation while blowing in steam, and the output from the top of the stripper (8) is fed to a fractionator (10) via a fractionator feed tank (9). Claim 1 describes a process in which the ammonia gas is supplied and rectified under pressure while blowing in steam, and the ammonia gas derived from the top of the column is cooled and recovered in a liquid ammonium tank (11). the method of. 6. The method according to claim 1, characterized in that the outlet temperature of the coke oven gas derived from the gas cooling device (1) in the cooling process (A) is set at 35 to 39°C. 7. Vapor (a) of the contactor (7) in the desulfurization process (C), fractionator feed tank (
9) vapor (b) and fractionator (10
), the oil purge (c) is continuously subjected to a desulfurization process (B
) before the wet desulfurization equipment (5), and if necessary, the product ammonia vapor (d),
The vapor (e) in the ammonium tank (11), the residual pressure purge (f) at the time of lorry shipment, or the ammonia-containing vapor (g) from other processes are processed batchwise or continuously into the wet desulfurization equipment (B) for the desulfurization process (B). 5. The method according to claim 5, characterized in that it is fed back to the cooling process (A) before step 5) or to the cooling process (A). 8. The method according to claim 1, characterized in that both (a) and (b) are carried out.