CN103418223A - Comprehensive desulphurization technology in coal chemical industry - Google Patents

Abstract

The invention discloses a comprehensive desulphurization technology in the coal chemical industry. The comprehensive desulphurization technology comprises the following steps: acidic gas containing hydrogen sulfide and coming from a low-temperature methanol washing device burns to generate mixed gas, and the mixed gas is subjected to two stages of cooling to separate out liquid sulfur for producing solid sulfur; sulphuric mixed gas separated out after cooling is subjected to secondary combustion so that all sulphureous components in the mixed gas are changed into SO2, tail gas generated after combustion and boiler flue gas of a heating power station are fully mixed and enter a desulphurization tower, circulating liquid containing aqua ammonia is used as an absorbent to absorb SO2 in a countercurrent contact way and react to generate ammonium sulfite, and ammonium sulfite is further oxidized to change into ammonium sulfate; desulphurized and purified flue gas is discharged into air through a chimney; ammonium sulfate solution at the bottom of the desulphurization tower enters a circulation tank and is crystallized to form the ammonium sulfate product. The comprehensive desulphurization technology adopts a novel combined desulphurization technology to replace the traditional Klaus Scott or Super Claus technology, and can effectively lower investment, improve recovery rate of sulfur and reduce discharge of sulfur.

Description

A kind of Coal Chemical Industry industry synthetic desulphurization technique

Technical field

The invention belongs to chemical field, particularly in a kind of Coal Chemical Industry industry, utilize the desulfurization group technology of claus reaction and ammonia absorption reaction.

Background technology

The sulfur recovery technology of having applied at present is a lot, according to product, has sulfur recovery to produce sulphur and sulfur recovery production sulfate technology.The Acidic Gas Treating technique that product is sulphur adopts Claus unit sulfur recovery unit usually, and this method is a kind of technique of maturation, and technology category is various, mainly contains traditional claus process, and the super Crouse of catalytic oxidation, with the claus process of SCOT vent gas treatment.

Traditional Crouse's recovery process is due to the equilibrium-limited that is subject to claus reaction, and the total sulphur rate of recovery of claus process is generally in the 95-98% left and right, and tail gas can't meet national existing environmental protection standard.Afterwards in order to improve sulfur recovery rate, catalytic oxidation super Claus Sulfur Recovery Technique and super excellent claus process have been developed again, reaction principle is basic identical, the main purpose of processing is all the sulfur content reduced in tail gas, the former adopts the mode of selective catalytic oxidation, the latter adopts the hydrogenation catalyst reactor, and all element sulphur hydrogenation are become to H ₂After S, then the selective oxidation catalyst, by H ₂S is oxidized to elementary sulfur, although total sulfur recovery can bring up to more than 99%, H in tail gas ₂The discharge of S does not also reach the requirement of national new standard.

Ammonia-process desulfurization technique, utilize the alkalescence of ammoniacal liquor to absorb the acid SO2 gas in flue gas, and by-product sulphur ammonium or ammonium sulfate fertilizer, be applicable to the flue gas desulfurization of any coal.Ammonia process is Wet Flue Gas Desulfurization Technique efficient, low power consuming, belongs to the liquid phase reaction, and reaction rate is fast, and the absorbent utilization rate is high, can keep at present desulfuration efficiency 99% left and right, due to original SO in flue gas ₂Content relatively low, the sulfur content after desulfurization is processed in tail gas reaches the requirement of national new standard fully.Using the maximum characteristics of wet method ammonia process is the resourcebility of SO2, pollutant SO2 can be reclaimed to the commercial prod that becomes high added value.Byproduct ammonium sulfate is a kind of nitrogenous fertilizer of function admirable, in China, has good market prospects.

In the present invention, traditional Crouse's sulfuration process and ammonia desulfurizing process are combined, not only decrease investment, but and the resource of realization pollutant, there is good society generalization prospect.

Summary of the invention

Purpose of the present invention just is to provide the group technology of a kind of Coal Chemical Industry industry sulfur recovery, reasonably traditional Crouse and ammonia desulfurizing process is combined, and reduces to greatest extent the discharge of pollutant, reaches the requirement of national up-to-date discharge standard.

The characteristics of the Sulfur Recovery Unit technology of generally applying in conjunction with the Coal Chemical Industry industry and the ammonia-process desulfurization technique of power industry maturation, combine a kind of synthetic desulphurization technique of applied range.The raw material consumed in technique is the ammoniacal liquor of Coal Chemical Industry by-product, realizes the resource flow process of pollutant, and its concrete technical scheme is as follows:

Its concrete technical scheme is as follows:

The first step: from the sour gas that contains hydrogen sulfide of low temperature washing device for methanol, the about 10400kg/h of flow, enter acid gas combustion furnace internal combustion, regulates AIR Proportional, and sour gas flow and air mass flow ratio are regulated between 0.3-1.5; Contain SO in mist after burning ₂, sulphur steam, residual H ₂S and other gas, between 350 ℃～500 ℃ of gas temperatures;

Second step: from combustion furnace, mist out is down to below 100 ℃ through the two-stage chilling temperature, separates out molten sulfur, and molten sulfur is for the production of solid sulfur;

The 3rd step: the mist of isolating sulphur after cooling enters tail-gas combustion stove, carries out second-time burning, and in the second-time burning process, in mist, sulfur component all becomes SO ₂, the tail gas after burning is delivered to thermo-power station with pipeline; Tail gas fully mixes with the boiler smoke of thermo-power station, controls SO in flue gas ₂Content's index is between 1200～1500mg/Nm3;

The 4th step: abundant mixed gas, through desulfurizing tower, utilizes the circulation fluid that contains ammoniacal liquor of Coal Chemical Industry by-product as absorbent, and counter current contacting absorbs SO ₂Reaction generates ammonium sulfite, and the desulfurizing tower bottom passes into air, the oxidized ammonium sulfate that becomes of the ammonium sulfite in ammonium sulfite solution; Purifying smoke SO after desulfurization ₂Below content 100mg/Nm3, emptying through chimney.

Ammonium sulfate at the bottom of the 5th step, desulfurizing tower enters circulating slot, after crystallization, produces ammonium sulfate product.

For realizing above-mentioned technique, the present invention provides a kind of Coal Chemical Industry industry synthetic desulphurization technique and synthesis desulfurating system thereof simultaneously.This system is to be connected in sequence by pipeline by sour gas burning furnace, two-stage cooling device, tail-gas combustion stove, desulfurizing tower and circulating slot.

The present invention adopts the new desulfurization process of combination to replace traditional Crouse's Scott or super Crouse's skill, can effectively reduce investment, improve the rate of recovery of sulphur, reduce the discharge capacity of sulphur, and can the reclaim sulfuric acid ammonium as the fertilizer of improvement basic soil, there is obvious economic benefit and social benefit.

The accompanying drawing explanation

Fig. 1 is process chart of the present invention.

Further illustrate technical scheme of the present invention below in conjunction with accompanying drawing.

The specific embodiment

As shown in Figure 1, processing step of the present invention is as follows:

The first step: from low temperature washing device for methanol, be rich in H ₂The sour gas of S enters sour gas burning furnace, proportionally allocates air into and is burnt; H occurs in stove ₂The S partial oxidation reaction, a part of H ₂The S burning conversion becomes SO ₂, the SO of generation ₂Again with remaining H ₂Claus reaction occurs and generates elemental sulfur in S; The chemical reaction occurred in stove is as follows:

H ₂S+3/2O ₂=SO ₂+H ₂O+Q ₁

H ₂S+3/2SO ₂=S+H ₂O+Q ₂

Above-mentioned sour gas flow and air mass flow ratio are regulated between 0.3-1.5;

Gaseous mixture after burning contains SO ₂, sulphur steam, residual H ₂S gas and other gas etc., and gas temperature is higher, and after at first gaseous mixture reclaims heat, through the condensation of two-stage cooling device, sulphur steam is separated with the form of molten sulfur, for the production of solid sulfur;

Second step: the mixed tail gas of isolating sulphur enters tail-gas combustion stove and carries out second-time burning, and sulfur component is converted into to SO fully ₂, the gas after burning further reclaims heat, delivers to the thermo-power station device after cooling;

The 3rd step: the gaseous mixture come from tail-gas combustion stove mixes with the boiler smoke from thermo-power station is full and uniform, controls between sulfur dioxide in flue gas content 1200～1500mg/Nm3.

The 4th step: mixed uniformly gas enters desulfurizing tower and the loop slurry counter current contacting is washed, lowers the temperature and absorbs, and contains the circulation fluid of ammonia absorbent by the SO in flue gas in this process ₂Absorb, reaction generates ammonium sulfite; Liquid containing ammonium sulfite carries out oxidation reaction with the oxidation air blasted from the desulfurizing tower bottom again, and sulfite oxidation is become to ammonium sulfate, forms the ammonium sulfate weak solution; The weak solution of liquid containing ammonium sulfate is sent into desulfurizing tower again, more further concentrated, after crystallization, obtain the ammonium sulfate slurries of solid content, thereby form closed circulation, after making like this ammonium sulfate concentrations reach setting in circulating slot, the ammonium sulfate slurries that generate are sent into sulphur ammonium after-treatment system, produce ammonium sulfate product.The chemical equation of desulfurization is as follows:

2NH ₃₊SO ₂+H ₂O=（NH ₄） ₂SO ₃

2（NH ₄） ₂SO ₃+O ₂=2（NH ₄） ₂SO ₄

The 6th step: remove SO ₂After clean flue gas after the demister demist, reach discharging standards, through smoke stack emission.

Claims (1)

1. a Coal Chemical Industry industry synthetic desulphurization technique, is characterized in that, step is as follows:

The first step: from the sour gas that contains the hydrogen sulfide amount of low temperature washing device for methanol, enter acid gas combustion furnace internal combustion, regulate AIR Proportional, sour gas flow and air mass flow ratio are regulated between 0.3-1.5; Contain SO in mist after burning ₂, sulphur steam and residual H ₂S, between 350 ℃～500 ℃ of gas temperatures;

Second step: from combustion furnace, mist out is down to below 100 ℃ through the two-stage chilling temperature, separates out molten sulfur, and molten sulfur is for the production of solid sulfur;

The 3rd step: the mist of isolating sulphur after cooling enters tail-gas combustion stove, carries out second-time burning, and in the second-time burning process, in mist, sulfur component all becomes SO ₂, the tail gas after burning is delivered to thermo-power station with pipeline; Tail gas fully mixes with the boiler smoke of thermo-power station, controls SO in flue gas ₂Content's index is between 1200～1500mg/Nm3;

The 4th step: abundant mixed gas, through desulfurizing tower, utilizes the circulation fluid that contains ammoniacal liquor of Coal Chemical Industry by-product as absorbent, and counter current contacting absorbs SO ₂Reaction generates ammonium sulfite, and the desulfurizing tower bottom passes into air, the oxidized ammonium sulfate that becomes of the ammonium sulfite in ammonium sulfite solution; Purifying smoke SO after desulfurization ₂Below content 100mg/Nm3, emptying through chimney;

The 5th step: the ammonium sulfate at the bottom of desulfurizing tower enters circulating slot, after crystallization, produces ammonium sulfate product.