KR100314846B1 - Method for refining coke gas by removing ammonia, hydrogen sulfide, and hydrogen cyanide from the coke gas - Google Patents

Method for refining coke gas by removing ammonia, hydrogen sulfide, and hydrogen cyanide from the coke gas Download PDF

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KR100314846B1
KR100314846B1 KR1019970071690A KR19970071690A KR100314846B1 KR 100314846 B1 KR100314846 B1 KR 100314846B1 KR 1019970071690 A KR1019970071690 A KR 1019970071690A KR 19970071690 A KR19970071690 A KR 19970071690A KR 100314846 B1 KR100314846 B1 KR 100314846B1
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hydrogen sulfide
ammonia
absorption tower
hydrogen
cyanide
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KR19990052235A (en
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김장규
이종규
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이구택
포항종합제철 주식회사
신현준
재단법인 포항산업과학연구원
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1406—Multiple stage absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456—Removing acid components
    • B01D53/1468—Removing hydrogen sulfide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1493—Selection of liquid materials for use as absorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/96—Regeneration, reactivation or recycling of reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
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    • B01D2251/2062—Ammonia

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Abstract

PURPOSE: Provided is a coke gas refinement method in which hydrogen cyanide is removed by being crystallized as ammonium thiocyanate, and ammonia and hydrogen sulfide are removed at the same time as ammonium polysulfide so that removal efficiency of the ammonia and hydrogen sulfide increases. CONSTITUTION: The method comprises the steps of feeding ammonium polysulfide generated from a hydrogen sulfide absorption tower(8) into a cyanide absorption tower(7) as an absorbent to absorb cyanide from a coke gas by forming ammonium thiocyanate solution; settling the ammonium thiocyanate solution in a settling tank, thereby removing cyanide from the coke gas heating the absorbent solution passing out the cyanide absorption tower(7) for evaporating vapor and thickening ammonia and hydrogen sulfide remained in the absorbent solution of the cyanide absorption tower(7) in an evaporator(19); absorbing hydrogen sulfide from the coke gas passing out the cyanide absorption tower(7) in the hydrogen sulfide absorption tower(8); oxidizing the absorbed hydrogen sulfide in a hydrogen sulfide oxidizing tower(23) to obtain sulfide from the hydrogen sulfide; causing reaction between the sulfide from the oxidizing tower(23) and ammonia from the hydrogen sulfide absorption tower, thereby removing hydrogen sulfide and ammonia together(8) as ammonium polysulfide; and returning the ammonium polysulfide to the cyanide absorption tower(7) as an absorbent of cyanide.

Description

코크스 가스중 암모니아, 황화수소 및 시안화수소 정제 방법Method for Purifying Ammonia, Hydrogen Sulfide and Hydrogen Cyanide in Coke Gas

본 발명은 코크스 가스를 정제하는 방법에 관한 것으로, 보다 상세하게는 코크스 가스중 암모니아, 황화 수소 및 시안화수소를 효율적으로 처리할 수 있는 정제 방법에 관한 것이다.The present invention relates to a method for purifying coke gas, and more particularly, to a purification method capable of efficiently treating ammonia, hydrogen sulfide and hydrogen cyanide in coke gas.

코크스 가스를 정제할 때 사용되는 종래의 방법은 암모니아를 제거하여 황산 용액에 흡수시키든지 분해로에서 분해하여 공기중에 방산시키는 방법이 있다. 암모니아를 분해로에서 분해하는 경우에는 암모니아와 황화수소가 섞여 있는 경우에 분해로 가스에 황산화물이 포함되어 공해 물질로서 배출되는 문제점이 있었다.Conventional methods used to purify coke gas include ammonia removal and absorption in sulfuric acid solutions or decomposition in cracking furnaces to dissipate in air. When ammonia is decomposed in a cracking furnace, when ammonia and hydrogen sulfide are mixed, there is a problem that sulfur dioxide is included in the cracking furnace gas and is emitted as a pollutant.

암모니아를 제거하는 또다른 방법으로는 인산 용액에 흡수시켜 순수한 암모니아로 회수하는 포삼법이 있다.Another method of removing ammonia is the ginseng method, which is absorbed in a phosphoric acid solution and recovered as pure ammonia.

그러나 암모니아보다도 제거하기 어렵고 공해를 유발하는 물질로서 황화수소와 시안화수소가 있는데 이들을 제거하기 위해 수많은 공정이 제안되어 왔다.However, hydrogen sulfide and hydrogen cyanide are more difficult to remove and cause pollution than ammonia, and numerous processes have been proposed to remove them.

황화 수소는 석회석에 흡수시켜 제거하는 방법으로 부터 출발하였으며, 산화철 등을 촉매로 이용하고 산화시켜 황으로 제거하는 건식 산화법과 건식 산화공정의 단점들을 극복하기 위하여 습식 공정이 개발되었는데 기본적인 목표는 필요한 부지 면적과 소요 인력을 줄이고 생산되는 황의 순도를 높이기 위해 개발되었다. 이 방법에서는 황화수소를 알칼리 용액에 흡수시킨 다음 산소 운반체를 이용하여 황화수소의 흡수율을 높이는데 촉매는 다시 재생탑에서 재생된다.Hydrogen sulfide was started by absorbing and removing limestone, and wet process was developed to overcome the shortcomings of dry oxidation process and dry oxidation process using iron oxide as catalyst and oxidized to remove sulfur. It was developed to reduce the area and manpower requirements and to increase the purity of the sulfur produced. In this method, hydrogen sulfide is absorbed into the alkaline solution and then oxygen carriers are used to increase the absorption rate of hydrogen sulfide, which is then regenerated in the regeneration tower.

습식 황화수소 제거법으로 대표적인 것은 일본에서 개발된 후막스 공정(Fummakss Process, Aromatics 27, 174, 1975)이 있는데 이 공정에서는 산소운반체인 촉매로서 피크린산을 사용하고 이와 비슷한 다카학스 공정(Takahax Process, Chemical Economy & Engineering Review 2,27, 1970)에서는 나프토퀴논-2-술폰산 나트륨을 촉매로 사용한다. 이와 같은 습식 공정은 값비싼 촉매를 이용하기 때문에 촉매를 재생하는 산화재생탑이 필요하고 따라서 순환 공정내에 여러 화합물이 축적함에 따른 부작용도 발생한다. 대표적인 축적물이 티오황산염과 티오시안산염이다. 이를 제거하기 위하여 순환액의 일부를 빼내 폐기하거나 혹은 과산화수소로 티오황산염을 황산염으로 산화시키는 방법도 있다.Representative of wet hydrogen sulfide removal method is the Fummakss Process (Aromatics 27, 174, 1975) developed in Japan, which uses picric acid as an oxygen carrier catalyst and similar Takahax Process (Takahax Process, Chemical Economy & Engineering Review 2,27, 1970) uses sodium naphthoquinone-2-sulfonate as a catalyst. Since the wet process uses an expensive catalyst, an oxidation and regeneration tower for regenerating the catalyst is required, and therefore, side effects due to the accumulation of various compounds in the circulation process also occur. Representative accumulations are thiosulfate and thiocyanate. In order to remove this, a part of the circulating fluid may be removed and discarded, or hydrogen peroxide may be oxidized to sulphate.

그러나 티오시안산염을 일정 농도 이하로 유지하기 위해서는 액의 일부를 폐기할 수 밖에 없다. 이 과정에서 폐수의 발생은 필연적이고 티오시안산염은 생물학적으로 난분해성이기 때문에 폐수 처리의 어려움이 따른다. 이 방법에서는 또한 공기에 의한 산화재생탑의 운전시 많은 양의 폐가스가 발생하여 이를 처리하는데 따른 어려움이 존재한다.However, in order to keep the thiocyanate below a certain concentration, part of the liquid has to be discarded. In this process, the generation of waste water is inevitable, and since thiocyanate is biologically difficult to decompose, it is difficult to treat the waste water. In this method, a large amount of waste gas is generated during operation of the air regeneration tower by air, and there is a difficulty in treating this.

암모니아와 황화수소를 제거하는 또다른 방법으로는 암모니아와 황화수소를 동시에 흡수하여 제거하는 펠드 공정(Feld Processes, Gas Purification, 4th ed., Gulf Publishing Company, p484, Houston, 1985)등이 있으나 여기에는 중간 매체로서 비교적 가격이 비싼 황산 이온으로 산화시키기 때문에 포함돤 복잡한 화학 반응을 조절하는 문제를 하결하지 못하여 실용화되지는 못하였다.Another method of removing ammonia and hydrogen sulfide is the Feld Processes, Gas Purification, 4th ed., Gulf Publishing Company, p484, Houston, 1985, which absorbs and removes ammonia and hydrogen sulfide simultaneously. As it is oxidized to relatively expensive sulfate ions, it cannot solve the problem of controlling complex chemical reactions.

습식 산화법이외에 암모니아 용액에 흡수된 황화수소를 암모니아와 함께 증류하여 클라우스 공정에서 분해시키는 방법이 있는데 이는 황화수소 가스를 촉매를 이용해 산화시켜 순수한 황으로 회수한다. 이 공정에서의 문제점은 촉매에 의한 산화 공정에서 많은 양의 폐가스가 발생하고 이를 처리하는데 어려움이 있으며 이 폐가스를 다시 코크스 가스중에 돌려보낼 경우 설비 부식 등의 문제를 일으키는 단점이 있다. 이 방법은 현재 코크스 공정에서 실용화된 방법이다.In addition to the wet oxidation method, hydrogen sulfide absorbed in the ammonia solution is distilled together with ammonia to decompose in the Klaus process. The hydrogen sulfide gas is oxidized with a catalyst and recovered as pure sulfur. The problem in this process is that a large amount of waste gas is generated in the oxidation process by the catalyst and it is difficult to treat it, and when this waste gas is returned to the coke gas again, there is a disadvantage of causing problems such as corrosion of equipment. This method is currently used in coke processes.

또한 위에서 열거한 황화수소 제거법들은 황화수소와 시안화수소를 동시에 제거하는 방법이기 때문에 발생 폐액에 시안 화합물이 포함되어 있어 생물학적 폐수 처리 공정에서 처리할 때 잘 처리되지 않는 단점이 있다. 또한 회수하여 유용하게 사용가능한 티오시안산염을 회수하지 못하는 단점도 있다.In addition, since the hydrogen sulfide removal methods listed above remove hydrogen sulfide and hydrogen cyanide at the same time, cyanide compounds are included in the generated waste liquid, and thus, there is a disadvantage in that they are not treated well when treated in a biological wastewater treatment process. In addition, there is a disadvantage that can not recover the useful thiocyanate can be recovered.

기존의 공정에서 시안 화합물을 따로 회수하지 못하는 단점을 보완하고자 다황화나트륨 용액에 흡수시켜 티오시안산 나트륨으로 회수하는 공정이 개발되었다(Coke and Chemistry, p20-22, 1984). 그러나 이 공정에서는 티오시안산염과 폐놀 회수에 주안점을 두고 있기 때문에 황화수소를 회수하고 처리시 발생하는 공해 물질과 그 처리 방법에 대하여는 언급된 바가 없다.In order to make up for the drawback of not recovering the cyanide compound separately from the existing process, a process for recovering sodium thiocyanate by absorbing it in sodium polysulfide solution has been developed (Coke and Chemistry, p20-22, 1984). However, since the process focuses on the recovery of thiocyanate and phenol, there is no mention of the pollutants generated during the recovery and treatment of hydrogen sulfide and their treatment.

이를 개선하기 위하여 최근에는 COG중 암모니아나 황화수소를 이용하여 황화수소 산화시 발생하는 황과 암모니아가 반응하여 발생하는 다황화암모늄 용액에 시안화수소를 흡수시키는 방법이 제안되었다.Recently, a method of absorbing hydrogen cyanide in an ammonium polysulfide solution generated by reacting sulfur and ammonia generated by hydrogen sulfide oxidation using ammonia or hydrogen sulfide in COG has been proposed.

그러나 상기 방법에서는 결정화기에서 가열할 때 발생하는 암모니아를 다량 함유한 수증기가 빠져나가고 이를 처리하는 방법이 필요하며 이의 보충을 위하여 별도의 순수 암모니아 회수 설비 및 이로 부터 암모니아를 보충받는 암모니아 포화기가 필요하게 된다.However, the above method requires a method for treating a large amount of ammonia vapor generated by heating in a crystallizer and treating the same. A supplementary pure ammonia recovery facility and an ammonia saturator supplemented with ammonia are required for replenishment. do.

또한 황화수소 흡수탑 이후에는 황화수소를 제거할 수 있는 방법이 없기 때문에 황화수소 흡수탑의 흡수 효율이 매우 높아야 하고 이를 위하여 고압 산소나 소석회 등을 사용하는 방법을 이용하게 되므로 부대 설비 등으로 인한 장치의 복잡화 내지는 대형화의 단점을 가지고 있다.In addition, since there is no method to remove hydrogen sulfide after the hydrogen sulfide absorption tower, the absorption efficiency of the hydrogen sulfide absorption tower should be very high, and for this purpose, a method using high pressure oxygen or slaked lime is used. It has the disadvantage of enlargement.

이에 본 발명의 목적은 시안화수소를 흡수하여 티오시안산 암모늄을 결정화하고 황화수소는 암모니아와 함께 흡수시켜 코크스 가스중 시안화수소, 암모니아 및 황화 수소의 흡수 효율을 증대시키는 정제 방법을 제공하려는데 있다.Accordingly, an object of the present invention is to provide a purification method of absorbing hydrogen cyanide to crystallize ammonium thiocyanate and absorbing hydrogen sulfide together with ammonia to increase the absorption efficiency of hydrogen cyanide, ammonia and hydrogen sulfide in coke gas.

도 1은 황화수소의 습식 산화법을 이용한 종래의 코크스가스 정제법을 도시한 도면이고,1 is a view showing a conventional coke gas purification method using a wet oxidation method of hydrogen sulfide,

도 2는 시안화수소를 포집하여 티오시안산 암모늄으로 배출하고 잔류 황화수소는 암모니아와 함께 흡수하는 본 발명에 의한 코크스 가스 정제법을 도시한 도면이다.FIG. 2 is a view illustrating a coke gas purification method according to the present invention in which hydrogen cyanide is collected and discharged to ammonium thiocyanate and residual hydrogen sulfide is absorbed together with ammonia.

*도면의 주요한 부호에 대한 설명** Description of Major Symbols in Drawings *

1... 코크스가스 포집관 2...기액 분리기1 ... coke gas collection pipe 2 ... gas separator

3... 냉각탑 4... 나프탈렌 흡수탑3 ... cooling tower 4 ... naphthalene absorption tower

5... 블로우어 6... 전기 집진기5 ... blower 6 ... electric dust collector

8... 황화수소 흡수탑 10... 냉각탑8 ... Hydrogen Sulfide Absorption Tower 10 ... Cooling Tower

11... 벤졸 흡수탑 12... 코크스 가스11 ... benzol absorption tower 12 ... coke gas

13... 재순환 안수 14... 타르13 ... Recycling Ordination 14 ... Tar

15... 안수타르 분리기 16... 증류 가스15 ... Anthur Separator 16 ... Distillation Gas

17... 폐수 18... 증류탑17.Wastewater 18.Distillation column

107... 암모니아 포집기 118... 산화탑107 ... ammonia collector 118 ... oxidation tower

119... 폐공기 처리 설비 120... 고액 분리기119 ... Waste Air Treatment Equipment 120 ... Solid-liquid Separator

121... 황화수소 흡수액 122... 황121 ... hydrogen sulfide absorbers 122 ... sulfur

123... 폐스 124... 폐가스123 ... wastes 124 ... waste gas

7... 시안화수소 흡수탑 9... 암모니아 흡수탑7 ... hydrogen cyanide absorption tower 9 ... ammonia absorption tower

19... 증발기 20... 침전기19 ... evaporator 20 ... settler

21... 티오시안산 암모늄 22... 암모니아 함유 수증기21 ... Ammonium thiocyanate 22 ... Water vapor containing ammonia

23... 황화수소 산화탑 24... 산소23 ... Hydrogen Sulfide Oxide Tower 24 ... Oxygen

25... 과산화수소 26... 중화조25 ... hydrogen peroxide 26 ... neutralization tank

27... 황산 28... 침전기27 ... sulfuric acid 28 ... precipitator

29... 황산암모늄29 ... Ammonium Sulfate

본 발명은The present invention

시안화수소 흡수탑 7에 흡수된 시안화수소에Hydrogen cyanide absorbed by the hydrogen cyanide absorption tower 7

황화수소 흡수탑 8로 부터 다황화암모늄을 첨가하여 티오시안산 암모늄을 제조한 다음 침전기 20에서 분리시켜 시안화수소를 처리하는 제1 단계;Adding ammonium polysulfide from the hydrogen sulfide absorption tower 8 to prepare ammonium thiocyanate, and then separating it in a precipitator 20 to treat hydrogen cyanide;

상기 시안화수소 흡수탑 7을 통과한 흡수액에 잔류하는 암모니아, 수증기 및 황화수소를 증발기 19에서 증발ㆍ농축시킨 다음,After evaporating and condensing ammonia, water vapor and hydrogen sulfide remaining in the absorbent liquid passing through the hydrogen cyanide absorption tower 7,

물은 황화수소 흡수탑 8에서 받은 다황화암모늄양만큼 증발시켜 황화수소 흡수탑 8의 흡수 유량을 일정하게 하며,Water is evaporated by the amount of ammonium polysulfide received from the hydrogen sulfide absorption tower 8 to make the absorption flow rate of the hydrogen sulfide absorption tower 8 constant.

이와 함께 다량의 암모니아를 증발시켜 황화수소 흡수탑 8내의 암모니아 농도를 높이고 나아가 황화수소 흡수액내 전체 암모니아 농도를 유지시키는 제2단계;A second step of increasing the ammonia concentration in the hydrogen sulfide absorption tower 8 by evaporating a large amount of ammonia and further maintaining the total ammonia concentration in the hydrogen sulfide absorption liquid;

황화수소 흡수탑 8에서 흡수한 황화수소는 황화수소 산화탑 23내로 운반시키고 산소를 가하여 황을 생성한 다음 전체 농도가 유지된 암모니아와 결합시켜 다황화암모늄을 생성후 상기 시안화수소 흡수탑 7로 순환시켜 제1 단계를 반복하는 제3단계;The hydrogen sulfide absorbed in the hydrogen sulfide absorption tower 8 is transported into the hydrogen sulfide oxidation tower 23, oxygen is added to form sulfur, and then combined with ammonia maintained at a total concentration to form ammonium polysulfide, and then circulated to the hydrogen cyanide absorption tower 7 A third step of repeating the steps;

이어서 상기 황화수소 흡수탑 8내에 잔류하는 황화수소와 암모니아는 과산화수소를 첨가하여 황화수소를 황산염으로 완전히 산화시키고,Subsequently, hydrogen sulfide and ammonia remaining in the hydrogen sulfide absorption tower 8 are added with hydrogen peroxide to completely oxidize hydrogen sulfide to sulfate,

상기 황산염을 암모니아와 반응시켜 황산암모늄으로 고정됨으로써 암모니아의 흡수 효율을 증가시키는 방식으로,In this manner, the sulfate is fixed with ammonium sulfate by reacting with ammonia to increase the absorption efficiency of ammonia,

암모니아 흡수탑 9에서 흡수하는 제4 단계; 및A fourth step of absorbing in the ammonia absorption tower 9; And

상기 단계에서 잔류하는 암모니아는 중화조 26에서 황산을 가하여 중화함으로써 암모니아를 전부 황산암모늄 형태로 전환시키고,The remaining ammonia in this step is neutralized by adding sulfuric acid in the neutralization tank 26 to convert all of the ammonia into ammonium sulfate form,

이중 과산화수소나 황산 용액으로 첨가되는 물의 양만큼만 암모니아 흡수탑 9로 순환시키고 나머지는 침전기 28에서 제거하는 제5 단계;로 이루어지는A fifth step of circulating in the ammonia absorption tower 9 by the amount of water added to the hydrogen peroxide or sulfuric acid solution and removing the remainder from the settler 28;

코크스 가스중 암모니아, 황화수소 및 시안화수소 정제 공정이 제공된다.A process for purifying ammonia, hydrogen sulfide and hydrogen cyanide in coke gas is provided.

이하, 본 발명을 도 1 및 2를 참조하여 상세히 설명한다.Hereinafter, the present invention will be described in detail with reference to FIGS. 1 and 2.

종래의 코크스 가스 정제 공정중 코크스 가스 포집관 1, 기액 분리기 2, 냉각탑 3, 나프탈렌 흡수탑 4 및 전기 집진기 5를 거친 다음 잔류하는 코크스 가스중 암모니아, 황화수소 및 시안화수소를 정제하기 위하여, 황화수소 흡수탑 전에 시안화수소 흡수탑 7을 설하고 황화수소 황화수소 흡수탑 8에 이어 암모니아 흡수탑 9을 설치함으로써 시안화수소, 황화 수소 및 암모니아를 동시에 정제한다.Hydrogen sulfide absorption tower in order to purify ammonia, hydrogen sulfide and hydrogen cyanide in the remaining coke gas after passing the coke gas collecting pipe 1, gas-liquid separator 2, cooling tower 3, naphthalene absorption tower 4 and electrostatic precipitator 5 during the conventional coke gas purification process. Hydrogen cyanide, hydrogen sulfide and ammonia are simultaneously purified by installing hydrogen cyanide absorption tower 7 and hydrogen sulfide absorption tower 8 followed by ammonia absorption tower 9.

시안화수소 흡수탑 7에 흡수된 시안화수소에 황화수소 흡수탑 8로 부터 다황화암모늄을 첨가하여 티오시안산 암모늄을 제조한 다음 침전기 20에서 자연 침강시켜 분리한다.The ammonium polysulfate was prepared by adding ammonium polysulfide from the hydrogen sulfide absorption tower 8 to the hydrogen cyanide absorbed by the hydrogen cyan absorption column 7 to prepare ammonium thiocyanate, followed by spontaneous sedimentation in a precipitate 20.

다만, 황화수소 흡수탑 8내에서 티오시안산 암모늄이 제조되는 반응이 정상 상태에 도달할 때까지는 반응을 원활하게 하기 위하여, 시안화수소 흡수탑 7내에 황화나트륨 및 황을 가하고 가열하여 다황화나트륨 용액을 제조하고 이를 시안화수소 흡수탑 7내에 흡수된 시안화수소와 반응시켜 티오시안산 나트륨을 제조하고 침전기 20에서 자연 침강에 의해 제거한다.However, in order to facilitate the reaction until the reaction for producing ammonium thiocyanate in the hydrogen sulfide absorption tower 8 reaches a steady state, sodium sulfide and sulfur are added and heated in the hydrogen cyanide absorption tower 7 to heat the sodium sulfide solution. It was prepared and reacted with hydrogen cyanide absorbed in the hydrogen cyanide absorption tower 7 to produce sodium thiocyanate and removed by natural sedimentation in Precipitator 20.

시안화수소 흡수탑에 흡수된 그밖의 암모니아, 수증기 및 황화수소는 증발기 19에서 증발하고 농축시킨다. 상기 증발하고 농축된 혼합액중 물은 황화수소 흡수탑 8에서 받은 다황화암모늄양만큼 증발시켜 황화수소 흡수탑 8의 흡수 유량을 일정하게 하며, 이와 함께 다량의 암모니아를 증발시켜 황화수소 흡수탑 8내의 암모니아 농도를 높이고 나아가 황화수소 흡수액내 전체 암모니아 농도를 유지시킨다.Other ammonia, water vapor and hydrogen sulfide absorbed in the hydrogen cyanide absorption tower are evaporated and concentrated in evaporator 19. The water in the evaporated and concentrated mixture is evaporated by the amount of ammonium polysulfide received in the hydrogen sulfide absorption tower 8 to make the absorption flow rate of the hydrogen sulfide absorption tower 8 constant, and the amount of ammonia in the hydrogen sulfide absorption tower 8 is increased by evaporating a large amount of ammonia. Increase and further maintain the total ammonia concentration in the hydrogen sulfide absorbent.

상기 황화수소 흡수탑 8에서 황화수소를 흡수한 용액은 황화수소 산화탑 23내에서산소 24를 공급하여 황을 생성한 다음 전체 농도를 일정하게 유지시킨 암모니아와 반응시켜 다황화암모늄을 생성한다.The hydrogen sulfide absorbing solution in the hydrogen sulfide absorption tower 8 supplies oxygen 24 in the hydrogen sulfide oxidation tower 23 to generate sulfur, and then reacts with ammonia having a constant concentration to produce ammonium polysulfide.

상기 산소는 황화수소와 반응하여 전량 다황화암모늄을 생성하는 것이 바람직한데,The oxygen is preferably reacted with hydrogen sulfide to produce a total amount of ammonium polysulfide,

이는 흡수된 황화수소로 부터 다황화암모늄 농도를 충분히 확보함으로써 황화수소를 최대한 제거하기 때문이다.This is because hydrogen sulfide is removed as much as possible by sufficiently securing the ammonium polysulfide concentration from the absorbed hydrogen sulfide.

또한 상기 황화수소 산화탑 23으로 부터 유량을 충분히 유지시킴으로써 생성된 다황화암모늄을 계속 시안화수소 흡수탑 7로 순환시켜 시안화수소를 티오시안산암모늄으로 결정화하는 단계를 반복함으로써 시안화수소를 최대한 제거한다.In addition, hydrogen cyanide is maximally removed by repeating the step of continuously circulating the ammonium polysulfide produced by maintaining a sufficient flow rate from the hydrogen sulfide oxide tower 23 to the hydrogen cyanide absorption tower 7 to crystallize hydrogen cyanide with ammonium thiocyanate.

이때 상기 증발기 19에서 발생하는 물, 황화수소와 암모니아 22등은 황화수소 산화탑 23으로 들어가기 때문에 시안화수소 흡수계와 황화수소 흡수계가 서로 교류하면서 전체적으로 암모니아의 농도를 유지시키는 역할을 한다. 이 계에서 암모니아의 소비량은 티오시안산암모늄으로 제거되는 양에 해당한다.At this time, since the water, hydrogen sulfide and ammonia 22 generated in the evaporator 19 enters the hydrogen sulfide oxidation tower 23, the hydrogen cyanide absorption system and the hydrogen sulfide absorption system interact with each other to maintain the concentration of ammonia as a whole. The consumption of ammonia in this system corresponds to the amount removed with ammonium thiocyanate.

황화수소 흡수탑 8에서 미처 흡수되지 못한 잔류 황화수소와 암모니아는 암모니아 흡수탑 9내에서 흡수되게 되는데 이때 황화수소는 과산화수소 25를 투입함으로써 황산염으로 산화되기 때문에, 미량의 황화수소까지도 거의 흡수할 수 있으며, 또한 생성된 황산염으로 인해 암모니아도 황산암모늄 형태로 고정되기 때문에 암모니아의 흡수 효율도 높이는 작용을 한다.Residual hydrogen sulfide and ammonia, which have not been absorbed in the hydrogen sulfide absorption tower 8, are absorbed in the ammonia absorption tower 9, where hydrogen sulfide is oxidized to sulphate by adding hydrogen peroxide, so that even a small amount of hydrogen sulfide can be absorbed. Because of the sulfate, ammonia is also fixed in the form of ammonium sulfate, which increases the absorption efficiency of ammonia.

상기 과산화수소가 과량일 때에는 암모니아와 반응하고 남은 과산화수소는 중화조 26에서 황화수소를 황산으로 전환시키게 되며, 과산화수소가 소량일 때에도 반응하지 못하고 빠져나가는 황화수소가 중화조에서 첨가하는 황산대신 황산암모늄을 생성하게 하여 중화조에서 황산을 과량 첨가할 부담을 줄이기 때문에 부식 및 한정된 사용 재질을 완화하는 측면에서 보다 좋다.When the excess hydrogen peroxide reacts with ammonia, the remaining hydrogen peroxide converts the hydrogen sulfide into sulfuric acid in the neutralization tank 26, and the hydrogen sulfide that does not react even when a small amount of hydrogen peroxide escapes produces ammonium sulfate instead of the sulfuric acid added in the neutralization tank. It is better in terms of mitigating corrosion and limited use materials because it reduces the burden of adding excessive sulfuric acid in the neutralization tank.

여기서 나오는 흡수액에는 상기 황산 암모늄뿐만 아니라 잔류 암모니아가 포함되어 있다. 따라서 중화조 26에서 황산 27을 첨가하면 암모니아를 완전히 중화시켜 잔류 암모니아가 전부 황산암모늄 형태로 전환된다. 따라서 상술한 바와 같이, 암모니아는 완전 중화되고 황산은 과량을 첨가하지 않아도 되므로 부식에 대한 부담이 줄어 사용 재질에 대한 제한이 완화될 수 있다.The absorbent liquid here contains residual ammonium as well as the ammonium sulfate. Thus, the addition of sulfuric acid 27 in the neutralization tank 26 completely neutralizes the ammonia, converting all of the residual ammonia into ammonium sulfate form. Therefore, as described above, since ammonia is completely neutralized and sulfuric acid does not need to be added in excess, the burden on corrosion can be reduced and the restriction on the material used can be relaxed.

이때 액이 계속 순환하면서 황산암모늄이 석출되기 때문에 석출되는 황산암모늄은 침전기 27에서 자연 침강함으로써 제거된다. 단 상기 과산화수소나 황산 용액으로 인해 첨가되는 물의 양만큼 결정화기에서 증발시킴으로써 순환액량을 일정하게 유지시키고 그 잔류 황산암모늄을 제거하여야 한다.At this time, since ammonium sulfate precipitates as the liquid continues to circulate, the precipitated ammonium sulfate is removed by spontaneous sedimentation in the precipitator 27. However, the amount of water added due to the hydrogen peroxide or sulfuric acid solution is evaporated in the crystallizer to keep the circulating fluid constant and remove the residual ammonium sulfate.

결과적으로 별도의 암모니아나 황이 첨가될 필요없이 결과적으로 코크스 가스중의 시안화수소, 암모니아 및 황화수소를 최대 효율로 정제하게 된다. 상기 시안화수소, 암모니아 및 황화수소를 정제한 코크스 가스는 냉각탑을 거쳐 벤졸 흡수탑 12에서 벤졸을 흡수함으로써 코크스 가스만을 배출하게 된다.As a result, hydrogen cyanide, ammonia and hydrogen sulfide in the coke gas are purified to the maximum efficiency without the need for the addition of separate ammonia or sulfur. The coke gas purified from the hydrogen cyanide, ammonia and hydrogen sulfide absorbs the benzene from the benzol absorption tower 12 through a cooling tower to discharge only the coke gas.

실시예Example

도 2에 도시한 장치에 질소 가스를 기준으로 암모니아 7g/N㎥, 황화 수소 5g/N㎥ 및 시안화수소 함량이 1.6g/N㎥인 혼합 가스를 사용하였고 가스 유량 70N㎥/h로 실험하였다. 흡수탑들은 모두 충진탑으로 하였다.In the apparatus shown in FIG. 2, a mixed gas having ammonia 7g / Nm3, hydrogen sulfide 5g / Nm3 and hydrogen cyanide content of 1.6g / Nm3 was used for the apparatus shown in FIG. 2, and the gas flow rate was 70Nm3 / h. The absorption towers were all packed towers.

시안화수소 흡수탑 통과후 혼합가스 중의 시안화수소의 농도는 0.002g/N㎥이었다. 이 때 흡수탑에 통과하는 흡수액의 유량은 110L/h가 되도록 하였다. 흡수탑 운전을 처음 시작할 때에는 반응이 정상상태에 도달할 때까지는 흡수액을 인위적으로 제조하게 되는데 이 흡수액은 황화나트륨을 4.5g/L로 녹이고 여기에 황을 15g/L로 첨가한 다음 가열한 다황화나트륨 용액을 200L 제조하여 사용하였다.The hydrogen cyanide concentration in the mixed gas after passing through the hydrogen cyanide absorption tower was 0.002 g / Nm 3. At this time, the flow rate of the absorbent liquid passing through the absorption tower was 110 L / h. At the start of the absorption tower operation, the absorbent liquid is artificially prepared until the reaction reaches a steady state. The absorbent liquid is dissolved in sodium sulfide at 4.5 g / L, and sulfur is added at 15 g / L, followed by heating polysulfide. 200L of sodium solution was prepared and used.

일단 운전이 시작된 다음에는 소비되는 황화나트륨을 보충하기 위하여 황화수소 흡수탑으로 부터 나오는 흡수액의 일부를 60g/L의 유량으로 공급하여 다황화암모니아 형태로 공급되게 하였다. 일단 정상상태에 도달하면 티오시안산 암모늄이 회수되는 결정의 양은 불순물을 포함하여 약 300g/h였다. 이중 불순물은 대부분이 황산암모늄이었으며 5%를 넘지 않았다.Once the operation was started, a portion of the absorbing liquid from the hydrogen sulfide absorption tower was supplied at a flow rate of 60 g / L to replenish the consumed sodium sulfide in the form of polysulfide ammonia. Once the steady state was reached, the amount of crystal recovering ammonium thiocyanate was about 300 g / h including impurities. Most of the impurities were ammonium sulfate and did not exceed 5%.

황화수소 흡수탑을 통과한 다음에는 혼합가스중 황화수소의 농도가 2.9g/N㎥ 정도까지 떨어졌다. 황화수소 흡수탑을 통과하는 흡수탑의 흡수액 유량은 120L/h를 유지하도록 하였다. 산화탑에 들어가는 산소의 압력은 2기압 정도였고 이 때 공급한 산소의 양은 평균 46.5L/h였다.After passing through the hydrogen sulfide absorption tower, the concentration of hydrogen sulfide in the mixed gas dropped to about 2.9 g / Nm3. The absorption liquid flow rate of the absorption tower passing through the hydrogen sulfide absorption tower was maintained at 120 L / h. The pressure of oxygen entering the tower was about 2 atm, and the amount of oxygen supplied was 46.5 L / h on average.

암모니아 흡수탑에서의 흡수액 유량은 120L/h정도였고 과산화수소의 투입량은 2L/h정도였으며, 황산 사용량은 99% 순도로 815g/h였다. 황산암모늄 생성량은 1.6kg/h였다. 암모니아의 최종 배출 농도는 0.03g/N㎥, 황화수소는 0.01g/N㎥였다.The flow rate of the absorbent liquid in the ammonia absorption tower was about 120 L / h, the amount of hydrogen peroxide input was about 2 L / h, and the amount of sulfuric acid used was 99% purity 815 g / h. The amount of ammonium sulfate produced was 1.6 kg / h. The final concentration of ammonia was 0.03 g / Nm 3 and hydrogen sulfide was 0.01 g / Nm 3.

상기한 바에 따르면, 본 발명에서는 암모니아 흡수 공정에서 시안화수소를 처리하고 황화수소와 암모니아를 동시에 흡수하여 암모니아와 황화수소의 흡수 효율을 증가시키고 유용한 물질인 티오시안산나트륨을 결정화시킴으로써, 설비를 단순화할 뿐만 아니라 흡수탑의 크기도 줄일 수 있다.According to the above, the present invention not only simplifies the equipment by treating hydrogen cyanide in the ammonia absorption process and simultaneously absorbing hydrogen sulfide and ammonia to increase the absorption efficiency of ammonia and hydrogen sulfide and crystallizing sodium thiocyanate, a useful substance, The size of the absorption tower can also be reduced.

또한 티오시안산 암모늄을 결정화하기 위한 증발기에서 발생하는 고농도의 암모니아를 다시 황화수소 흡수액으로 쓸 수 있도록 함으로써 별도의 암모니아나 황을 보충할 필요가 없다.In addition, the high concentration of ammonia generated in the evaporator for crystallization of ammonium thiocyanate can be used as a hydrogen sulfide absorption liquid, so that no additional ammonia or sulfur needs to be replenished.

나아가 암모니아 흡수탑에서 흡수된 암모니아는 중화조에서 정확하게 중성으로 조정되기 때문에 과량의 황산을 사용하는 종래 방법에 비하여 부식 부담이 줄어 사용재질의 조건이 완화될 수 있다.Furthermore, since the ammonia absorbed in the ammonia absorption tower is precisely adjusted to neutrality in the neutralization tank, the burden of corrosion is reduced compared to the conventional method using an excessive amount of sulfuric acid, so that the conditions of the material used can be alleviated.

Claims (3)

시안화수소 흡수탑 7에 흡수된 시안화수소에Hydrogen cyanide absorbed by the hydrogen cyanide absorption tower 7 황화수소 흡수탑 8로 부터 다황화암모늄을 첨가하여 티오시안산 암모늄을 제조한 다음 침전기 20에서 분리시켜 시안화수소를 처리하는 제1 단계;Adding ammonium polysulfide from the hydrogen sulfide absorption tower 8 to prepare ammonium thiocyanate, and then separating it in a precipitator 20 to treat hydrogen cyanide; 상기 시안화수소 흡수탑 7을 통과한 흡수액에 잔류하는 암모니아, 수증기 및 황화수소를 증발기 19에서 증발ㆍ농축시킨 다음,After evaporating and condensing ammonia, water vapor and hydrogen sulfide remaining in the absorbent liquid passing through the hydrogen cyanide absorption tower 7, 물은 황화수소 흡수탑 8에서 받은 다황화암모늄양만큼 증발시켜 황화수소 흡수탑 8의 흡수 유량을 일정하게 하며,Water is evaporated by the amount of ammonium polysulfide received from the hydrogen sulfide absorption tower 8 to make the absorption flow rate of the hydrogen sulfide absorption tower 8 constant. 이와 함께 다량의 암모니아를 증발시켜 황화수소 흡수탑 8내의 암모니아 농도를 높이고 나아가 황화수소 흡수액내 전체 암모니아 농도를 유지시키는 제2단계;A second step of increasing the ammonia concentration in the hydrogen sulfide absorption tower 8 by evaporating a large amount of ammonia and further maintaining the total ammonia concentration in the hydrogen sulfide absorption liquid; 황화수소 흡수탑 8에서 흡수한 황화수소는 황화수소 산화탑 23내로 운반시키고 산소를 가하여 황을 생성한 다음 전체 농도가 유지된 암모니아와 결합시켜 다황화암모늄을 생성후 상기 시안화수소 흡수탑 7로 순환시켜 제1 단계를 반복하는 제3단계;The hydrogen sulfide absorbed in the hydrogen sulfide absorption tower 8 is transported into the hydrogen sulfide oxidation tower 23, oxygen is added to form sulfur, and then combined with ammonia maintained at a total concentration to form ammonium polysulfide, and then circulated to the hydrogen cyanide absorption tower 7 A third step of repeating the steps; 이어서 상기 황화수소 흡수탑 8내에 잔류하는 황화수소와 암모니아는 과산화수소를 첨가하여 황화수소를 황산염으로 완전히 산화시키고,Subsequently, hydrogen sulfide and ammonia remaining in the hydrogen sulfide absorption tower 8 are added with hydrogen peroxide to completely oxidize hydrogen sulfide to sulfate, 상기 황산염을 암모니아와 반응시켜 황산암모늄으로 고정됨으로써 암모니아의 흡수 효율을 증가시키는 방식으로,In this manner, the sulfate is fixed with ammonium sulfate by reacting with ammonia to increase the absorption efficiency of ammonia, 암모니아 흡수탑 9에서 흡수하는 제4 단계; 및A fourth step of absorbing in the ammonia absorption tower 9; And 상기 단계에서 잔류하는 암모니아는 중화조 26에서 황산을 가하여 중화함으로써 암모니아를 전부 황산암모늄 형태로 전환시키고,The remaining ammonia in this step is neutralized by adding sulfuric acid in the neutralization tank 26 to convert all of the ammonia into ammonium sulfate form, 이중 과산화수소나 황산 용액으로 첨가되는 물의 양만큼만 암모니아 흡수탑 9로 순환시키고 나머지는 침전기 28에서 제거하는 제5 단계;로 이루어지는A fifth step of circulating in the ammonia absorption tower 9 by the amount of water added to the hydrogen peroxide or sulfuric acid solution and removing the remainder from the settler 28; 코크스 가스중 암모니아, 황화수소 및 시안화수소 정제 방법Method for Purifying Ammonia, Hydrogen Sulfide and Hydrogen Cyanide in Coke Gas 제1항에 있어서, 상기 황화수소 흡수탑 7로 부터 다황화암모늄의 공급이 원활한 정상 상태에 도달할 때까지는, 상기 제1 단계전에The method of claim 1, wherein the supply of ammonium polysulfide from the hydrogen sulfide absorption tower 7 reaches a smooth steady state before the first step. 시안화수소 흡수탑 7내에서 황화나트륨에 황을 가하고 가열한 다황화나트륨 용액을 제조한 다음 시안화수소 흡수탑 7에 흡수된 시안화수소와 반응시켜 티오시안산 나트륨을 제조하고 침전기 20에서 제거하는 단계;를 거침을 특징으로 하는 방법To prepare sodium polysulfide solution by adding sulfur to sodium sulfide in hydrogen cyanide absorption tower 7 and heating it, and then reacting with hydrogen cyanide absorbed in hydrogen cyanide absorption tower 7 to prepare sodium thiocyanate and removing in precipitate 20 Characterized by 제1항에 있어서, 상기 황화수소 산화탑 23에서 생성되는 다황화암모늄 농도 및 상기 다황화암모늄을 시안화수소 흡수탑 7로 보내는 유량을 충분히 확보함으로써 황화수소 흡수탑 흡수액만으로 시안화수소를 티오시안산 암모늄으로 회수함을 특징으로 하는 방법The hydrogen cyanide is recovered as ammonium thiocyanate using only the hydrogen sulfide absorption tower absorption liquid by ensuring sufficient concentration of ammonium polysulfide produced in the hydrogen sulfide oxide tower 23 and a flow rate for sending the ammonium polysulfide to the hydrogen cyanide absorption tower 7. Method characterized by
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KR100516462B1 (en) * 2000-12-15 2005-09-23 주식회사 포스코 Method for collecting nh4scn from cog purification process
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