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CN-122010056-A - Advanced treatment and sulfur recovery integrated process for tail gas

CN122010056ACN 122010056 ACN122010056 ACN 122010056ACN-122010056-A

Abstract

The invention relates to the technical field of coal chemical tail gas treatment and resource recovery, and discloses an integrated process for advanced tail gas treatment and sulfur recovery, which comprises the following steps: firstly, carrying out pretreatment on acidic tail gas generated by a coal chemical industry device, wherein liquid water and impurity particles in the tail gas are removed through a gas-liquid separation device in the pretreatment process, the gas-liquid separation device adopts a cyclone separation and silk screen filtration combined structure, the gas inlet speed of a cyclone separation section is controlled to be 15-20 m/s, and the separation efficiency is more than or equal to 95%. The technology removes impurities through cyclone separation and screen filtration in a pretreatment stage to avoid catalyst blockage, ensures that the ammonia decomposition rate is more than or equal to 99.9%, the hydrocarbon combustion rate is more than or equal to 99.5%, and the two-stage low-temperature catalytic conversion unit is matched with ZnO-CuO modified activated carbon for deep adsorption, the emission concentration of SO2 in tail gas is less than or equal to 400mg/m < 3 >, far exceeds the environmental protection standard, and the organic sulfur and inorganic sulfur are removed cooperatively, SO that the comprehensive treatment is improved by 40% compared with the traditional technology.

Inventors

  • YAN LIQIANG
  • JIANG ZICHENG

Assignees

  • 连云港碱业有限公司

Dates

Publication Date
20260512
Application Date
20251212

Claims (8)

  1. 1. An integrated process for advanced treatment of tail gas and sulfur recovery is characterized by comprising the following steps: Firstly, carrying out pretreatment on acidic tail gas generated by a coal chemical industry device, wherein liquid water and impurity particles in the tail gas are removed through a gas-liquid separation device in the pretreatment process, the gas-liquid separation device adopts a cyclone separation and screen filtration combined structure, the gas inlet speed of a cyclone separation section is controlled to be 15-20 m/s, the separation efficiency is more than or equal to 95%, a screen filtration section adopts a 316L stainless steel wire mesh, and the liquid water content of the pretreated tail gas is ensured to be less than or equal to 0.1% (volume fraction) and the impurity particle content is ensured to be less than or equal to 1mg/m < 3 >; step two, carrying out component analysis on the pretreated tail gas, adopting an online gas chromatograph to detect the concentration of H 2 S、SO 2 、COS、CS 2 、CO 2 and hydrocarbon substances in the tail gas in real time, wherein the detection frequency is 1 time/min, the detection precision is +/-0.1 percent (volume fraction), and calculating the total sulfur content and the organic sulfur ratio of the tail gas according to the detection result, wherein the total sulfur content calculation formula is as follows Wherein the method comprises the steps of Is the total sulfur content of the tail gas, 、 、 、 、 The volume concentrations of the corresponding components are respectively, The molar mass of the hydrocarbon sulfur compound is calculated as the organic sulfur ratio The organic sulfur is required to occupy less than or equal to 2 percent of detection error; Step three, then entering an integrated reaction system, wherein the system comprises a high-temperature thermal reaction unit, a low-temperature catalytic conversion unit and a deep adsorption unit which are sequentially connected in series; the high-temperature thermal reaction unit adopts a combustion furnace with a lining, the lining material is corundum mullite refractory brick, the temperature resistance limit is more than or equal to 1750 ℃, air preheated to 200-250 ℃ is introduced into the combustion furnace, the air preheating adopts a tail gas waste heat recovery device, the preheating efficiency is more than or equal to 80%, the molar ratio of H 2 S and O 2 in the combustion furnace is controlled to be 2.8-3.2:1 by adjusting the air-air ratio, and 1/3 volume of H 2 S is ensured to be according to a reaction formula Oxidation to SO 2 and simultaneously ammonia in the tail gas according to the reaction formula Completely decomposed and hydrocarbons according to the reaction type Fully burning, wherein the temperature of an outlet of a combustion furnace is controlled to 1250-1350 ℃, the gas residence time is more than or equal to 2 seconds, the ammonia decomposition rate is more than or equal to 99.9%, and the hydrocarbon combustion rate is more than or equal to 99.5%; wherein the multistage low temperature catalytic conversion unit is provided with two stages of catalytic reactors in series, and specifically comprises: The organic sulfur hydrolysis-Claus dual-function catalyst is filled in a primary catalytic reactor, gamma-Al 2 O 3 is used as a carrier of the catalyst, 10% -15% (mass fraction) of TiO 2 and 5% -8% (mass fraction) of Co-Mo active components are loaded on the catalyst, the particle size of the catalyst is 3-5 mm, the specific surface area is more than or equal to 200m < 2 >/g, the inlet temperature of the primary reactor is controlled to be 280-320 ℃, the pressure is 0.12-0.15 MPa, the space velocity is 800-1200 h -1 , and COS in tail gas is caused to react according to the following conditions Hydrolysis, CS 2 according to the reaction type Hydrolysis ensures that the COS hydrolysis rate is more than or equal to 98 percent, the CS 2 hydrolysis rate is more than or equal to 95 percent, and the Claus reaction simultaneously occurs ; The low-temperature high-activity Claus catalyst is filled in the secondary catalytic reactor, tiO 2 is used as a carrier and is loaded with 3% -5% (mass fraction) La 2 O 3 auxiliary agent, the particle size of the catalyst is 2-4 mm, the specific surface area is more than or equal to 150m < 2 >/g, the inlet temperature of the secondary reactor is controlled to be 220-240 ℃, the pressure is consistent with that of the primary reactor, and the airspeed is 1500-2000H -1 , SO that the residual H 2 S and SO 2 further undergo Claus reaction, and the conversion rate is more than or equal to 92%; The deep adsorption unit adopts ZnO-CuO modified active carbon adsorbent, the particle size of the adsorbent is 1-3 mm, the pore volume is more than or equal to 0.8cm < 3 >/g, the adsorption temperature is 80-120 ℃, the pressure is 0.1-0.12 MPa, the space velocity is 500-800H -1 , the residual H 2 S、SO 2 and unhydrolyzed organic sulfur in the tail gas are deeply adsorbed, and the total sulfur content of the tail gas after adsorption is ensured to be less than or equal to 10mg/m < 3 >; Step four, carrying out centralized treatment on liquid sulfur generated by each unit, respectively entering a shell-and-tube condensation cooler from process gas at the outlets of a high-temperature thermal reaction unit and a low-temperature catalytic conversion unit, introducing process gas into a tube side, introducing desalted water into the tube side, controlling the temperature of the outlet of the process gas to be 130-150 ℃ by adjusting the flow of the desalted water, enabling the condensation rate of the liquid sulfur to be more than or equal to 99%, enabling the condensed liquid sulfur to enter a liquid sulfur degassing unit, adding a quinoline catalyst into the degassing unit, enabling the liquid sulfur to be circularly sprayed by a liquid sulfur circulating pump, introducing nitrogen to sweep, removing dissolved H 2 S in the liquid sulfur to be less than or equal to 5ppm, and returning sulfur-containing waste gas generated by degassing to the high-temperature thermal reaction unit for retreatment; And fifthly, solidifying the degassed liquid sulfur into columnar particles by adopting a rotary drum forming machine, wherein the rotating speed of the forming machine is 5-8 r/min, the cooling water temperature is 20-30 ℃, the water content of the particles is less than or equal to 0.1%, and finally, quantitatively packaging by using an automatic packaging machine by 50 kg/bag, wherein the packaging precision is +/-0.5 kg, the total sulfur recovery rate of the whole process is more than or equal to 99.9%, and the concentration of tail gas emission SO 2 is less than or equal to 400mg/m < 3 >.
  2. 2. The integrated process for advanced treatment of tail gas and recovery of sulfur according to claim 1, wherein the gas-liquid separation device for pretreatment of acidic tail gas comprises: The cyclone separation section adopts a tangential inlet structure, the diameter ratio of the inlet pipe diameter to the diameter of the separation section is 0.2-0.3, the length of the separation section to the diameter ratio of the separation section is 3-4, the half apex angle of the cone section is 10-15 degrees, and the flow field distribution is optimized through Computational Fluid Dynamics (CFD) simulation, so that the airflow forms stable rotational flow with the centrifugal force field strength of more than or equal to 1000g in the separation section, and liquid water drops with the particle size of more than or equal to 10 mu m and impurity particles can be efficiently separated; The stainless steel wire mesh of the silk screen filtering section adopts a multi-layer folding structure, the number of layers is 5-8, the distance between silk screens is 5-10 mm, and the flow velocity uniformity of air flow in the filtering section is less than or equal to +/-5% through the design of uniform arrangement; an online gas chromatograph for analyzing the components of the tail gas after pretreatment adopts a double detector combination of a hydrogen Flame Ionization Detector (FID) and a Thermal Conductivity Detector (TCD), wherein the FID is used for detecting hydrocarbon substances, the TCD is used for detecting H 2 S、SO 2 、COS、CS 2 and CO 2 , a chromatographic column adopts a GDX-104 packed column and a SE-30 capillary column, and the column temperature adopts a programmed temperature rise: the initial temperature is kept at 40 ℃ for 5 minutes, then the temperature is increased to 200 ℃ at 10 ℃ per minute and kept for 10 minutes, the separation degree of each component is ensured to be more than or equal to 1.5, and the single detection period is less than or equal to 5 minutes so as to meet the real-time regulation and control requirement; In order to avoid corrosion of high-concentration H 2 S to a chromatograph, a corrosion-resistant sampling probe made of hastelloy C-276 is arranged in front of a sample inlet, a sampling pipeline is made of polytetrafluoroethylene and is heated to 120-150 ℃, the temperature of heating is accurately controlled by a PID temperature controller, and the temperature fluctuation is less than or equal to +/-2 ℃; meanwhile, an online filter is arranged on the sampling pipe line, and automatic blowback is performed periodically.
  3. 3. The integrated process for advanced treatment of tail gas and sulfur recovery according to claim 1, wherein in a high-temperature thermal reaction unit of the integrated reaction system, a combustion furnace lining adopts a double-layer structure, an inner layer is corundum mullite refractory bricks, an outer layer is light insulating bricks, an expansion joint with the width of 5-8 mm is arranged between the double-layer lining, ceramic fiber cotton is filled, and the heat loss of the combustion furnace is ensured to be less than or equal to 5% through heat loss calculation; The fuel gas of the combustion furnace preferentially adopts hydrocarbon substances separated from tail gas, the hydrocarbon heat value is detected in real time through an online heat value analyzer, and the theoretical air quantity is calculated, wherein the formula is Wherein the method comprises the steps of The air is the theoretical air quantity, In order to achieve the desired fuel gas consumption, For the excess air ratio, For the low heat value of the fuel gas, the mixing ratio of the fuel gas and the air is controlled by a proportional regulating valve; The outlet temperature of the combustion furnace adopts cascade adjustment of 'temperature-air quantity/combustion-accompanying fuel gas', and when the temperature is lower than 1250 ℃, the supply quantity of the combustion-accompanying natural gas is automatically increased, and the formula is that Wherein the method comprises the steps of In order to accompany the natural gas quantity of burning, Is a coefficient of proportionality and is used for the control of the power supply, A temperature is set for the outlet and the temperature of the outlet, As the actual temperature of the outlet port, The treatment capacity of the tail gas; When the temperature is higher than 1350 ℃, the air supply is automatically increased to dilute and cool, and the fluctuation of the outlet temperature is ensured to be less than or equal to +/-20 ℃; An ultraviolet flame detector is arranged in the combustion furnace, when flame extinction is detected, fuel gas supply is immediately cut off, nitrogen is introduced for blowing, and backfire explosion is prevented; The outlet of the combustion furnace is provided with a quenching section, the temperature of the process gas is rapidly reduced from 1250-1350 ℃ to 300-350 ℃ by spraying desalted water, the corrosion of the high-temperature process gas to subsequent equipment is avoided, and the spraying amount of the desalted water is calculated, wherein the formula is that Wherein the method comprises the steps of For the use amount of the desalted water, For the mass flow rate of the process gas, For the specific heat capacity of the process gas, For the inlet temperature of the quenching section, For the quench section outlet temperature, Is the latent heat of vaporization of the water, Is the specific heat capacity of water, Is the desalted water temperature.
  4. 4. The integrated process for advanced treatment of tail gas and recovery of sulfur as claimed in claim 1, wherein the preparation process of the organic sulfur hydrolysis-Claus bifunctional catalyst in the primary catalytic reactor of the multi-stage low-temperature catalytic conversion unit is as follows: roasting the gamma-Al 2 O 3 carrier for 2-3 hours at the temperature of 500-600 ℃ to remove adsorbed water and impurities; Then, immersing the roasted carrier into a mixed impregnating solution containing tetrabutyl titanate (TiO 2 precursor), cobalt nitrate (Co precursor) and ammonium molybdate (Mo precursor) by adopting an isovolumetric impregnation method, wherein the Ti concentration in the impregnating solution is 0.5-1.0 mol/L, co concentration and 0.1-0.2 mol/L, mo concentration and 0.2-0.3 mol/L, the impregnation temperature is 60-80 ℃, and the impregnation time is 4-6 hours; drying for 4-6 hours at 120-150 ℃ after the impregnation is finished, and roasting for 3-4 hours at 500-550 ℃ to decompose the precursor into oxide and load the oxide on the surface of the carrier; The prepared catalyst needs to be subjected to activity evaluation under the condition of simulating tail gas, and can be put into use when the COS hydrolysis rate is more than or equal to 98%, the CS 2 hydrolysis rate is more than or equal to 95% and the Claus reaction conversion rate is more than or equal to 85% under the conditions of 280 ℃ and 0.1MPa and 1000h -1 airspeed.
  5. 5. The integrated process for advanced treatment of tail gas and recovery of sulfur according to claim 1, wherein the high-temperature and high-activity Claus catalyst takes anatase TiO 2 as a carrier in a secondary catalytic reactor of the multistage low-temperature catalytic conversion unit, and the preparation process is as follows: Roasting the TiO 2 carrier for 1-2 hours at 450-500 ℃; Immersing the roasted carrier into an immersion liquid containing lanthanum nitrate (La 2 O 3 precursor) by adopting an excessive immersion method, and immersing for 8-12 hours at room temperature; Drying at 100-120 ℃ for 8-10 hours, and roasting at 550-600 ℃ for 2-3 hours; The particle size of the prepared catalyst is controlled to be 2-4 mm through screening, the bulk density is 1.2-1.4 g/cm <3 >, the BET specific surface area is more than or equal to 150m < 2 >/g, the pore volume is more than or equal to 0.5cm <3 >/g, and the conversion rate of the Claus reaction is more than or equal to 92% under the condition of simulating tail gas at 220 ℃, 0.1MPa and 2000h -1 airspeed.
  6. 6. The integrated process for advanced treatment of tail gas and recovery of sulfur as claimed in claim 1, wherein the preparation process of the ZnO-CuO modified activated carbon adsorbent of the advanced adsorption unit is as follows: the coconut shell activated carbon is selected as a raw material, water vapor is adopted for activation at 800-900 ℃, the specific surface area of the activated carbon after activation is more than or equal to 1000m < 2 >/g, and the pore volume is more than or equal to 1.0cm < 3 >/g; Immersing activated carbon into a mixed impregnating solution containing zinc nitrate (ZnO precursor) and copper nitrate (CuO precursor) by adopting a co-impregnating method, wherein the impregnating temperature is 50-60 ℃ and the impregnating time is 6-8 hours; drying at 120-150 ℃ for 6-8 hours, and roasting at 300-350 ℃ for 2-3 hours to decompose the nitrate precursor into ZnO and CuO and uniformly load the ZnO and CuO on the surface of the activated carbon; The prepared adsorbent needs to be subjected to adsorption performance test under the condition of simulating tail gas, and can be put into use after the adsorption penetration time is more than or equal to 100 hours.
  7. 7. The integrated process for advanced treatment of tail gas and sulfur recovery according to claim 1 is characterized in that the liquid sulfur condensation cooler adopts a shell-and-tube structure, tube bundle materials are 316L stainless steel, tube passes are 2-4, shell passes adopt baffle plate structures, heat exchange efficiency is improved by strengthening the turbulence degree of the shell passes, the total heat transfer coefficient of a heat exchanger is more than or equal to 200W/(m <2 >. DEG C), the process control of the condensation cooler adopts closed-loop regulation of outlet temperature-desalination water flow, the temperature of outlet process gas of the tube passes is detected in real time through a platinum resistance thermometer, when the temperature is higher than 150 ℃, the desalination water flow of the shell passes is automatically increased, when the temperature is lower than 130 ℃, the desalination water flow is automatically reduced, the temperature of the outlet of the process gas is ensured to be stable at 130-150 ℃, and the temperature fluctuation is less than or equal to +/-3 ℃; The shell side is provided with a differential pressure liquid level meter, the liquid level is controlled to be 100+/-20 mm above the top of the heat exchange tube, when the liquid level is too high, the liquid discharge valve is automatically opened to discharge redundant desalted water, and when the liquid level is too low, the water supplementing valve is automatically opened to supplement the desalted water, so that dry burning or heat exchange efficiency reduction is prevented; The condensed liquid sulfur enters a sulfur seal tank through a 316L stainless steel pipe with a steam jacket at the bottom, and the sulfur seal height of the sulfur seal tank is calculated according to the formula Wherein the method comprises the steps of The height of the sulfur seal is set to be the sulfur seal height, To condense the cooler outlet process gas pressure, Is the density of the liquid sulfur and the liquid sulfur, The gravity acceleration is 1.2, the safety coefficient is used for ensuring the sulfur seal to be reliable without leakage of process gas, the sulfur seal tank is made of 316L stainless steel, the design volume is 1.5-2 times of the liquid sulfur hour yield, and the breather valve is arranged on the tank top to prevent unsmooth transportation of the liquid sulfur caused by overhigh or overlow pressure in the tank.
  8. 8. The integrated process for advanced treatment of tail gas and sulfur recovery according to claim 1, wherein the liquid sulfur degassing unit adopts a tower structure, and 3-5 layers of spiral nozzle spraying devices are arranged in the tower to ensure that liquid sulfur is uniformly sprayed to form a liquid film and prolong the contact time with nitrogen; the quinoline catalyst for degassing is selected from 2,2' -biquinolinyl disulfide, and is continuously injected into a liquid sulfur pipeline at the top of the degassing tower through a metering pump, wherein the catalyst injection amount is calculated according to a formula of catalyst liquid sulfur, and the catalyst is catalyst mass flow, and the liquid sulfur is liquid sulfur mass flow; the liquid sulfur circulating pump adopts a magnetic drive pump, so that the circulation rate of the liquid sulfur in the degassing tower reaches 5-8 times, and the H 2 S removal effect is enhanced; The nitrogen purging system adopts nitrogen with the purity of more than or equal to 99.99 percent, the nitrogen is uniformly distributed at the bottom of the degassing tower through an annular porous pipe distributor, the flow of the nitrogen is controlled to be 1-2 times/H of the volume of the liquid sulfur through a mass flowmeter, the nitrogen is ensured to be fully contacted with the liquid sulfur, and the H 2 S content in the degassed liquid sulfur is less than or equal to 5ppm; The top of the degasser is provided with a silk screen demister to prevent liquid sulfur fog drops from being carried out along with sulfur-containing waste gas; the drum of the drum forming machine is made of 316L stainless steel, cooling water is introduced into the drum, the solidifying time of liquid sulfur on the surface of the drum is controlled to be 10-15 seconds by adjusting the rotating speed of the drum and the flow rate of the cooling water, and the strength of formed particles is more than or equal to 50N without crushing phenomenon; The automatic packaging machine adopts weighing type packaging, and the packaged sulfur bags are conveyed to a steel structure sulfur storage shed through a conveying belt.

Description

Advanced treatment and sulfur recovery integrated process for tail gas Technical Field The invention relates to the technical field of tail gas treatment and resource recovery in coal chemical industry, in particular to an integrated process for advanced treatment of tail gas and sulfur recovery. Background The traditional coal chemical acid tail gas treatment process has four core pain points, severely restricts the environment protection standard and the resource utilization rate, and is difficult to meet the industrial production requirement: The sulfur removal is incomplete, the emission does not reach the standard, the traditional process mostly adopts a single Claus reaction, the organic sulfur (COS, CS 2) cannot be effectively treated, the organic sulfur hydrolysis rate is less than or equal to 80%, the deep removal link is lost, the total sulfur content of the tail gas is often more than 50mg/m < 3 >, the emission concentration of SO 2 is more than 800mg/m < 3 >, the environmental protection standard is not met (GB 16297-1996), and the environmental protection punishment risk is faced. The method has the advantages of low resource recovery rate and serious waste, namely, the recovery of the sulfur only depends on simple condensation, the dissolved H 2 S in the liquid sulfur is not removed (the content is more than or equal to 50 ppm), the sulfur-containing waste gas generated by degassing is directly discharged, the total sulfur recovery rate is less than or equal to 95%, the waste of the sulfur resource is serious, meanwhile, the waste heat of the tail gas is not effectively utilized, and the energy consumption is high (the unit treatment energy consumption is more than or equal to 100 kWh/ton of tail gas). The method has the advantages of poor process stability, high operation and maintenance cost, low catalyst activity (the conversion rate of the Claus reaction is less than or equal to 85%), easy blockage or over-temperature inactivation due to impurities, frequent replacement (the replacement period is less than or equal to 6 months), poor corrosion resistance of equipment, easy equipment aging caused by high-temperature tail gas and acidic medium (the service life is less than or equal to 3 years), and the operation and maintenance cost accounts for more than 30% of the total production cost. The method has the advantages of low automation degree, complex operation, lack of real-time component analysis and closed-loop control, dependence on manual adjustment of process parameters, easiness in occurrence of problems of unbalanced air-air ratio, temperature fluctuation and the like, reduction of reaction efficiency, no interlocking protection system, and incapability of timely and easily causing safety accidents (such as tempering and overpressure) in fault treatment. Disclosure of Invention The invention aims to provide an integrated process for advanced treatment of tail gas and sulfur recovery, which aims to solve the problems in the background technology. In order to achieve the purpose, the invention provides the following technical scheme that the integrated process for deeply treating tail gas and recycling sulfur comprises the following steps: Firstly, carrying out pretreatment on acidic tail gas generated by a coal chemical industry device, wherein liquid water and impurity particles in the tail gas are removed through a gas-liquid separation device in the pretreatment process, the gas-liquid separation device adopts a cyclone separation and screen filtration combined structure, the gas inlet speed of a cyclone separation section is controlled to be 15-20 m/s, the separation efficiency is more than or equal to 95%, a screen filtration section adopts a 316L stainless steel wire mesh, and the liquid water content of the pretreated tail gas is ensured to be less than or equal to 0.1% (volume fraction) and the impurity particle content is ensured to be less than or equal to 1mg/m < 3 >; step two, carrying out component analysis on the pretreated tail gas, adopting an online gas chromatograph to detect the concentration of H 2S、SO2、COS、CS2、CO2 and hydrocarbon substances in the tail gas in real time, wherein the detection frequency is 1 time/min, the detection precision is +/-0.1 percent (volume fraction), and calculating the total sulfur content and the organic sulfur ratio of the tail gas according to the detection result, wherein the total sulfur content calculation formula is as follows Wherein the method comprises the steps ofIs the total sulfur content of the tail gas,、、、、The volume concentrations of the corresponding components are respectively,The molar mass of the hydrocarbon sulfur compound is calculated as the organic sulfur ratio The organic sulfur is required to occupy less than or equal to 2 percent of detection error; Step three, then entering an integrated reaction system, wherein the system comprises a high-temperature thermal reaction unit, a low-temperature catalytic convers