KR100270091B1 - Method of treating sulphur compounds - Google Patents

Abstract

PURPOSE: A method is provided to efficiently treating vapor of water into which hydrogen sulfide is primarily divided in a coke oven by completely oxidizing the vapor of water into which hydrogen sulfide is primarily divided in a coke oven with an inert gas, and circulating through hydrogen sulfide collecting process after converting sulfur dioxide into hydrogen sulfide in the reduction process. CONSTITUTION: In treating sulfur compounds in vapor of water into which hydrogen sulfide is primarily divided in a coke oven after first treating hydrogen sulfide in coke oven gas, the method for efficiently treating the water into which hydrogen sulfide is primarily divided in a coke oven comprises the steps of converting the sulfur dioxide into hydrogen sulfide in a reduction reactor after high temperature oxidizing the vapor of water into which hydrogen sulfide is primarily divided in a coke oven in an oxidation furnace, thereby oxidizing ammonia into water and nitrogen, hydrogen sulfide into sulfur dioxide and water, cyanic acid into nitrogen, carbon dioxide and water, and hydrocarbon into carbon dioxide and water; and circulating by collecting the hydrogen sulfide.

Description

Efficient Treatment of Sulfur Compounds in Ordinal Steam

The present invention relates to an effective method for treating sulfur compounds in ordinal steam in which hydrogen sulfide is firstly separated. It relates to a method of circulating hydrogen sulfide after treatment.

The coke oven gas generated in the coke manufacturing process of steel mills contains more than 50% of hydrogen and is used as a high quality fuel. It contains a large amount of ammonia and hydrogen sulfide, and the ordination is produced during the ammonia and hydrogen sulfide capture process, which removes it primarily.

The main component of the ordination consists of water, ammonia, hydrogen sulfide and other impurities.

Conventional ordination removes the hydrogen sulfide component, incinerates it, discharges it into the atmosphere, and hydrogen sulfide is recovered in the form of elemental sulfur in the Klaus process.

The hydrogen sulfide to be recovered in the present invention is a very poor condition because it contains excess water vapor (about 70% by volume) and excess ammonia (about 20% by volume).

Direct oxidation of hydrogen sulfide includes the Klaus process, the MODOP process, and the superclaus process.

The Klaus process is a high-concentration hydrogen sulfide-containing gas treatment process that converts and recovers elemental sulfur through the Klaus reaction. In the three-stage catalytic reaction process, the sulfidation yield is about 95-98%.

2H ₂ S + SO ₃ → 3S + 2H ₂ O (1)

The reaction formula (1) is a reversible reaction in which the thermodynamic equilibrium exists, and if the reaction gas contains a large amount of water, the sulfidation yield is decreased, and the maximum sulfur recovery yield can be obtained only by adjusting the ratio of H ₂ S / SO ₂ to an equivalent ratio.

Low concentration hydrogen sulfide-containing gas treatment process has been mainly developed as a TGT (Tail Gas Treatment) process for the treatment of hydrogen sulfide, which is not removed in the Klaus process, and as a recent dry process is a MODOP process and a superclaus process.

In both processes, hydrogen sulfide is directly reacted with air in the presence of a catalyst and converted to elemental sulfur as shown in Scheme (2).

H ₂ S + 1/2 O ₂ → S + H ₂ O (2)

Catalytic reactions of the MODOP process (Oil and Gas Journal, Jan 11,63,1988) are irreversible or when the reaction gas contains about 12% by volume of water, the sulfur recovery rate is greatly reduced to 70% or less, and H ₂ S / SO The ratio of ₂ to the equivalence ratio can be obtained to obtain the maximum yellow yield.

The Super Klaus process (Oil and Gas Journal, 86 (41), 68, 1988) supplements the above disadvantages and is known to have no effect on the catalytic activity even in the presence of excess oxygen and moisture. not,

Also, gases containing hydrogen sulfide are mostly inert gases and generally contain some moisture.

Patent applications 93-15403 and 93-31657 by the present inventors demonstrated that the presence of excess ammonia as excess moisture, oxygen and impurities does not affect the activity of the catalyst. However, in addition to reaction (2), oxidation of ammonia such as reaction (3) occurs during the catalytic reaction, making it difficult to control the reaction.

2NH ₃ + 3 / 2O ₂ → N ₂ + 3H ₂ O (3)

In this regard, the present inventors have found a method for selectively removing hydrogen sulfide in the form of elemental sulfur (S) and ammonium thiosulfate ((NH ₄ ) ₂ S ₂ O ₃ ) from a sulfur-containing mixed gas containing excess water vapor and ammonia. (Korean Patent Application Nos. 93-15403 and 93-31657).

However, since the ammonia partially oxidizes, it is difficult to control the temperature of the reactor due to the heat of oxidization, and it is necessary to separate the generated elemental sulfur and ammonium thiosulfate, and since the reaction gas contains a large amount of ammonia, it is incinerated. Must be subjected to further processing such as

Accordingly, an object of the present invention relates to a method of efficiently treating ordination steam by completely oxidizing the ordination vapor with an inert gas, converting double sulfur dioxide to hydrogen sulfide in the reduction process, and then circulating the hydrogen sulfide through the hydrogen sulfide collection process.

1 is a process schematic diagram for carrying out the method according to the invention.

* Explanation of symbols for main parts of the drawings

1: oxidation reactor 2: burner

3,6: coke oven gas 4,7: cooler

5: reduction reactor 8: hydrogen sulfide capture device

According to the present invention, in the first treatment of hydrogen sulfide in coke oven gas and then in the treatment of sulfur compounds in ordination steam, the ophthalmic vapors are hot-oxidized in an oxidation furnace-ammonia is water and nitrogen, hydrogen sulfide is sulfur dioxide and water, silver cyanate Nitrogen, carbon dioxide and water, and hydrocarbons are oxidized with carbon dioxide, and then converting the sulfur dioxide into hydrogen sulfide in a reduction reactor; and collecting and circulating the hydrogen sulfide.

Hereinafter, the present invention will be described in detail.

According to the present invention, sulfur dioxide and other inert gases are obtained by completely oxidizing anhydrous steam containing excess ammonia, water vapor, and hydrogen sulfide through a flame oxidation reaction and a catalytic decomposition reaction in an oxidation furnace, and the sulfur dioxide is hydrogen or coke oven gas. It is hydrogenated under a catalyst, converted to hydrogen sulfide, and then collected and circulated to exclude the influence of reaction (3) and to not release sulfur oxides into the atmosphere.

In the present invention, the ordinal steam causes a combustion reaction with the air in the burner so that most of the components are completely oxidized.

The main reaction is shown in Scheme (4) below.

2NH ₃ + 3 / 2O ₂ → N ₂ + 3H ₂ O

H ₂ S + 3 / 2O ₂ → SO ₂ + H ₂ O

2HCN + 5 / 2O ₂ → N ₂ + 2CO ₂ + H ₂ O

CmHn + (m + n / 4) O ₂ → mCO ₂ + n / 2H ₂ O (4)

Unreacted ammonia was decomposed on a catalyst consisting mainly of nickel and magnesium.

NH ₃ → 1 / 2N ₂ + 3 / 2H ₂ (5)

Since the purpose of the oxidation furnace is to completely oxidize the water vapor, the amount of air required for combustion is required.

The gas completely oxidized in the furnace contains sulfur dioxide, nitrogen, water and carbon dioxide. The gas is cooled in a cooler, mixed with hydrogen or a coke oven gas, which is a hydrogen-containing gas, in a reduction reactor as shown in Equation 6 below. The sulfur dioxide is reduced to hydrogen sulphide, which is then detected in a cooler and sent to a hydrogen sulphide capture process for processing.

SO ₂ + 3H ₂ → H ₂ S + 2H ₂ O (6)

In the present invention, the operation is easy because the amount of oxygen relative to the mixed gas in the oxidation furnace operation is operated in excess of the combustion equivalent ratio.

That is, even if oxygen is introduced at a combustion equivalent ratio or more, the unreacted oxygen remaining after the oxidation reaction is easily removed by introducing and burning hydrogen-containing gas at the rear of the oxidation furnace.

The excess oxygen used for the mixed gas oxidation may affect the reduction catalyst, so it is preferable to introduce 1: 1 to 1: 1.5 in the combustion equivalent ratio.

Meanwhile, the remaining hydrogen gas used to remove oxygen in the hydrogen-containing gas is used as a reaction gas of a reduction reactor. The hydrogen gas may be replaced with coke oven gas containing excess of 50% hydrogen. The coke oven gas has the dual effect of continuously repeating the process of capturing and circulating hydrogen sulfide as intended in the present invention.

According to the method of the present invention, the high temperature required for the oxidation reactor 1 has the advantage that the operating temperature can be maintained without charge of additional fuel only by the calorific value of ammonia and hydrogen sulfide in the reaction formulas (2) and (3).

The operating temperature is preferably 1000-1200 ° C or more without complete oxidation of the mixed gas and the installation. If the operating temperature is less than 1000 ℃ problem occurred that the complete oxidation does not occur during the mixed gas oxidation. If the temperature exceeds 1200 ℃ problem occurred in the equipment itself.

The deammonia gas passed through the oxidation reactor 1 is a reduction reactor using hydrogen-containing gas as the reducing gas in a reduction reactor 5 in which alumina is loaded with cobalt and molybdenum-containing catalyst (Co-Mo / Al ₂ O ₃ ). The temperature was converted to hydrogen sulfide at 300 ° C.

The gas passed through the oxidation furnace and the reduction reactor was collected through a hydrogen sulfide capture process, washed with water and concentrated to circulate the recycled hydrogen sulfide.

As described above, according to the method of the present invention, it is easy to operate the oxidation furnace without introducing additional fuel, and it is possible to circulate without discharging sulfur compounds by collecting hydrogen sulfide while simultaneously removing ammonia.

Hereinafter, embodiments of the present invention will be described.

Example 1

Conversion Rate of Sulfur Dioxide in Reduction Reactor

301 / min of ordination consisting of 3% by volume of hydrogen sulfide, 30% by volume of ammonia, 5% by volume of carbon dioxide, and 62% by volume of water and 401 / 1nin of air were introduced into the oxidation furnace, and flame oxidation was carried out at 1100 ° C. Cooled to 300 ° C. in a chiller. As a result of analysis of the product after the reaction, hydrogen sulfide and ammonia were not completely oxidized and detected. The gas was charged into a reduction reactor, hydrogen was introduced in 31 / min, and the catalyst was reduced using Co-Mo / Al ₂ O ₃ . As a result, the conversion rate from sulfur dioxide to hydrogen sulfide was more than 99%.

Example 2

Sulfur Dioxide Conversion with Coke Oven Gas in a Reduction Reactor

Except for introducing 61 / min of coke oven gas in place of hydrogen, the experiment was conducted in the same manner as in Example 1 and the reduction reaction resulted in a conversion rate of sulfur dioxide to hydrogen sulfide of 99% or more. Coke oven gas could be used.

Example 3

Effect of Ordination on Temperature of Oxidation Furnace

Except that the temperature of the oxidation furnace was changed to 700-1200 ℃, the experiment was conducted in the same manner as in Example 1 and the reduction reaction resulted in the complete oxidation does not occur at a temperature below 1000 ℃ unreacted ammonia and hydrogen sulfide was detected It can be seen that the temperature required for is 1000-1200 ℃.

In the present invention, the hydrogen sulfide-containing ordination is completely oxidized into an inert gas and sulfur dioxide in an oxidizing furnace, and then converted to sulfur sulfide through hydrogen reduction and then sent to a hydrogen sulfide collection process, whereby the ordination is directly oxidized. Due to the exothermic reaction, it is difficult to control the reaction, and it solves the problem of corrosion or by-products caused by sulfur dioxide when it is completely oxidized and sent to the hydrogen sulfide collection process, and does not emit sulfur compounds in the atmosphere.

Claims (3)

In the primary treatment of hydrogen sulphide in coke oven gas followed by the treatment of sulfur compounds in ordinal steam, the hot water is oxidized in an oxidation furnace to ammonia with water and nitrogen, hydrogen sulphide with sulfur dioxide and water, cyanic acid with nitrogen, carbon dioxide and water, and And oxidizing the hydrocarbon with carbon dioxide and then converting the sulfur dioxide into hydrogen sulfide in a reduction reactor; and collecting and circulating the hydrogen sulfide. The method of claim 1 wherein the oxidation reaction occurs at 1000-1200 ° C. The method of claim 1, wherein the amount of oxygen relative to the ordinal steam is 1: 1 to 1: 1.5 in terms of the combustion equivalent ratio of oxygen.