WO2020135135A1 - 处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置 - Google Patents

处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置 Download PDF

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WO2020135135A1
WO2020135135A1 PCT/CN2019/125764 CN2019125764W WO2020135135A1 WO 2020135135 A1 WO2020135135 A1 WO 2020135135A1 CN 2019125764 W CN2019125764 W CN 2019125764W WO 2020135135 A1 WO2020135135 A1 WO 2020135135A1
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tower
unit
desulfurization
sulfur
absorption
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PCT/CN2019/125764
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English (en)
French (fr)
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张素利
张爽
王嵩林
刘元德
白玮
赵虎
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中冶焦耐(大连)工程技术有限公司
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/69—Sulfur trioxide; Sulfuric acid
    • C01B17/74—Preparation
    • C01B17/76—Preparation by contact processes
    • C01B17/80—Apparatus
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/24—Sulfates of ammonium
    • C01C1/242—Preparation from ammonia and sulfuric acid or sulfur trioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/24—Sulfates of ammonium
    • C01C1/245—Preparation from compounds containing nitrogen and sulfur
    • C01C1/246—Preparation from compounds containing nitrogen and sulfur from sulfur-containing ammonium compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Definitions

  • the present disclosure relates to the technical field of incineration of sulfur-containing waste liquid in the coking industry, in particular to a process and device for processing low-purity sulfur and secondary salt waste liquid from coke oven gas desulfurization, which uses "oxygen-rich combustion, two-to-two absorption "Acid-making technology, and suitable for the treatment of low-quality sulfur and desulfurization byproduct waste liquid produced by the ammonia wet oxidative desulfurization process of coke oven gas.
  • the by-product sulfur produced by removing H 2 S from coal gas contains impurities such as pulverized coal, tar, and naphthalene, resulting in low product purity and difficulty in marketing.
  • impurities such as pulverized coal, tar, and naphthalene
  • Sulfur resources have not been effectively and reasonably used, and they have not been able to generate the value they deserve.
  • the above desulfurization process generates ammonium thiocyanate, ammonium thiosulfate and other secondary salt waste liquid during the desulfurization and decyanation process.
  • concentration of secondary salt in the system is high, it will seriously affect the efficiency of gas desulfurization and decyanation, and aggravate equipment corrosion.
  • the currently used secondary salt waste liquid treatment processes are: 1 Waste liquid is mixed with coking coal and sent to the coke oven for incineration and decomposition; and, 2 Extraction of ammonium thiocyanate and ammonium thiosulfate secondary salts.
  • the production practice shows that the waste liquid of secondary salt is mixed into coking and coal blending and sent to the coke oven for incineration and decomposition process.
  • the present disclosure provides a process and device for treating low-purity sulfur and secondary salt waste liquid by using the "oxygen-enriched combustion, two-turn two-suction" acid production technology to desulfurize coke oven gas, which fundamentally completely solves the problem of coke oven gas
  • the problems of low-purity sulfur recovery and utilization of ammonia-based wet oxidative desulfurization process and the harmless treatment of desulfurization secondary salt waste liquid have improved the sulfur recovery rate.
  • the sulfuric acid produced can be used as a raw material for the production of ammonium sulfate by coke oven gas deamination. This achieves the dual goals of recycling of sulfur resources and environmental protection.
  • the present disclosure provides a process for treating low-purity sulfur and secondary salt waste liquid from coke oven gas desulfurization.
  • the process flow includes a raw material pretreatment process, an incineration process, a waste heat recovery process, a purification process, Drying process, conversion process, absorption process, exhaust gas cleaning process, in which the incineration process uses oxygen-enriched air combustion, conversion process and absorption process uses secondary conversion, secondary absorption.
  • the raw material pretreatment process uses sedimentation centrifugal separation and concentration technologies to treat the sulfur foam liquid produced by the coal gas desulfurization process.
  • the process of the raw material pretreatment process includes: sending the sulfur foam liquid from the sulfur foam tank of the desulfurization unit to a horizontal centrifuge, and after the solid-liquid two-phase centrifugal separation, the filtrate enters the filtrate
  • the tank is then pumped out by the filtrate pump, part of it is sent to the concentration tower, and the rest is returned to the desulfurization tower of the desulfurization unit;
  • the sulfur paste separated from the centrifuge enters the slurry tank and is forcibly mixed with the desulfurization sub-salt concentrated liquid from the concentration tower to prepare
  • the raw material sulfur slurry is sent to the slurry storage tank, and then sent to the incinerator by the slurry transfer pump;
  • the steam discharged from the concentration tower enters the condensation tower to condense, and the condensate is sent back to the desulfurization tower of the desulfurization unit for use;
  • the non-condensable gas enters the negative pressure gas pipeline of the gas purification device.
  • the raw material pretreatment process is all completed in closed equipment and pipes.
  • the process of the incineration process includes: the raw material sulfur slurry fed into the incinerator from the raw material pretreatment process is atomized by the process liquid compressed by the waste liquid spray gun at a temperature of 1050-1250°C
  • the suspended elemental sulfur in the raw sulfur slurry and the sulfur element in the desulfurization side salt are converted into SO 2 .
  • the oxygen concentration in the oxygen-enriched air is 25%-45%.
  • the oxygen-enriched air is prepared by mixing directly supplied pure oxygen with combustion air or using a molecular sieve pressure swing adsorption process.
  • dilute sulfuric acid with a mass concentration of 0.5%-5% produced in the purification process is sent to the ammonium sulfate unit for recycling without waste liquid being discharged.
  • the conversion process uses “3+1" 4-stage catalyst bed, secondary conversion, and "III, I-IV, II” heat exchange process flow, and the conversion tower is in order from top to bottom Stage I-IV catalyst bed.
  • the "3+1" 4-stage catalyst bed used in the conversion process is secondarily converted into a dry contact method.
  • the catalyst before the SO 2 process gas enters the catalyst bed of the first and fourth stages of the converter, the catalyst is heated at the initial start-up stage.
  • the process of the absorption process includes: the primary conversion and the secondary conversion of the process gas from the conversion process enter the first absorption tower and the second absorption tower, respectively.
  • the exhaust gas cleaning process uses an alkaline method for desulfurization, which includes: the acid-making exhaust gas discharged from the absorption process enters the exhaust gas washing tower, and uses an alkaline liquid spray to absorb residual SO 2 and sulfuric acid mist in the exhaust gas The excess absorption liquid in the exhaust gas washing tower is sent to the biochemical unit for processing.
  • the tail gas cleaning process uses ammonia desulfurization, which includes: the acid-making tail gas discharged from the absorption process enters the tail gas washing tower, and sprays ammonia water to absorb residual SO 2 and sulfuric acid mist in the tail gas;
  • the excess ammonium sulfite-ammonium sulfate solution in the exhaust gas washing tower is sent to the raw material pretreatment process to be concentrated with the filtrate to make a sulfur slurry, or it is oxidized into ammonium sulfate solution by air, and then sent to the ammonium sulfate unit to prepare ammonium sulfate. No waste liquid is discharged.
  • Another aspect of the present disclosure provides a device used in a process for treating low-purity sulfur and secondary salt waste liquid provided by the present disclosure for coke oven gas desulfurization, which includes a raw material pretreatment unit, an incineration unit, a waste heat recovery unit, a purification unit, Drying unit, conversion unit, absorption unit, exhaust gas cleaning unit, raw material pretreatment unit, incineration unit, waste heat recovery unit, purification unit, drying unit, conversion unit, absorption unit and exhaust gas cleaning unit are arranged in order according to the process flow, of which raw materials
  • the pretreatment slurry output pipeline of the pretreatment unit is connected to the incinerator of the incineration unit, the outlet pipeline of the incinerator is connected to the waste heat boiler of the waste heat recovery unit, and the flue gas outlet pipeline of the waste heat boiler is connected to the flue gas inlet of the humidification tower of the purification unit
  • the outlet pipe of the electric demister A of the purification unit is connected to the drying tower of the drying unit, and the outlet pipe of the converter
  • the raw material pretreatment unit includes a foam tank, a filtrate tank, a slurry tank, a centrifuge, and a slurry storage tank.
  • the outlet line of the foam tank is connected to the inlet of the centrifuge through a pump, and the filtrate outlet of the centrifuge It is connected to the filtrate tank, the outlet of the sulfur paste of the centrifuge is connected to the slurry tank, and the outlet of the slurry tank is connected to the slurry storage tank, and a mechanical stirrer is provided in both the slurry tank and the slurry storage tank.
  • the exhaust gas cleaning unit includes an exhaust gas scrubber, an electric demister B, and a chimney.
  • the exhaust gas outlet of the exhaust gas scrubber is connected to the electric demister B and the electric gas demister B Connect the chimney.
  • the exhaust gas cleaning unit includes an exhaust gas washing tower, an ammonia absorption tower, an electric demister B, and a chimney.
  • the exhaust gas outlet of the exhaust gas washing tower is connected to the ammonia absorption tower, and the exhaust gas outlet of the ammonia absorption tower Connected to the electric demister B, the flue gas outlet of the electric demister B is connected to the chimney, the ammonium sulfate solution outlet of the ammonia absorption tower is connected to the exhaust gas scrubber, and the ammonium sulfite-ammonium sulfate solution outlet of the exhaust gas scrubber is connected to the raw material pretreatment unit Concentration tower.
  • both the first absorption tower and the second absorption tower are provided with process soft water make-up lines.
  • the incineration process of the present disclosure uses "oxygen-enriched combustion, two-to-two absorption” acid production technology to treat coke oven gas desulfurization to produce low-purity sulfur and secondary salt waste liquid.
  • Oxygen-enriched combustion technology effectively reduces the amount of process gas and increases the concentration of SO 2 in the process gas. Save construction investment and operating costs, and ensure the self-heating balance of the two-to-two-suction technology;
  • the conversion process and absorption process use two-to-two absorption technology to increase the SO 2 conversion rate from 97.5% to more than 99.9%, which significantly improves the sulfur recovery rate, greatly reduces the SO 2 content in the exhaust gas after the absorption process, and improves the process Environmental protection level.
  • FIG. 1 is a schematic diagram of a process flow for treating low-purity sulfur and secondary salt waste liquid provided by coke oven gas desulfurization according to one embodiment of the present disclosure (the tail gas cleaning process uses alkaline desulfurization).
  • FIG. 2 is a schematic diagram of a process flow for processing low-purity sulfur and secondary salt waste liquid provided by coke oven gas desulfurization according to another embodiment of the present disclosure (ammonia desulfurization is used in the tail gas cleaning process).
  • the process flow includes raw material pretreatment process, incineration process, waste heat recovery process, purification process, drying process, conversion process,
  • the incineration process uses oxygen-enriched air for combustion
  • the conversion process and absorption process use secondary conversion and secondary absorption.
  • the process of the raw material pretreatment process includes: sending the sulfur foam liquid from the sulfur foam tank 1 of the desulfurization unit to the horizontal centrifuge 5, after centrifugal separation of the solid and liquid phases, the filtrate enters the filtrate tank 3, and then is pumped out by the filtrate pump , A part is sent to the concentration tower 8 and the rest is sent back to the desulfurization unit of the desulfurization unit; the sulfur paste separated from the centrifuge 5 enters the slurry tank 4 and is forcibly mixed with the desulfurization sub-salt concentrate from the concentration tower 8 to obtain raw material sulfur
  • the slurry is sent to the slurry storage tank 6, and then sent to the incinerator 32 by the slurry transfer pump; the steam discharged from the concentration tower 8 enters the condensing tower 9 to condense, and the condensate is sent back to the desulfurization tower of the desulfurization unit; the condensing tower 9
  • the discharged non-condensable gas enters the negative pressure gas pipeline
  • the technical characteristics of the raw material pretreatment process include, for example:
  • the process of the incineration process includes: after the raw material sulfur slurry fed into the incinerator 32 by the raw material pretreatment process is atomized by the compressed air of the process of the waste liquid spray gun, at a temperature of 1050-1250°C, such as 1050, 1100, 1150, 1120, At 1125°C, the elemental sulfur incineration technology is controlled by stages to convert the suspended elemental sulfur in the raw sulfur slurry and the sulfur element in the desulfurization sub-salt to SO 2 ; and, a small amount of SO 3 is still produced.
  • the main chemical incineration and decomposition reactions occurring in the incinerator 32 include the following:
  • Oxygen-enriched air is used for combustion in the incinerator 32, and the oxygen concentration in the oxygen-enriched air is 25%-45%, such as 25%, 30%, 35%, 40%, and 45%.
  • the required oxygen-enriched air can be prepared by mixing directly supplied pure oxygen with combustion air, or by using molecular sieve pressure swing adsorption process, and then sent to the heater through the oxygen-enriched air blower 33, heated by steam and heated, then sent Combustion chambers up to 32 sections of incinerators are used for combustion.
  • the heat required for the combustion of the incinerator 32 is partly supplied by the reaction heat released by the above combustion reaction, and the rest is supplied by the combustion-supporting coke oven gas which is sent to the burner in the furnace by a gas pressurizer.
  • the technological characteristics of the incineration process include, for example:
  • Fluidized feed of sulfur slurry prepared by suspending elemental sulfur and concentrated waste liquid, air atomized incineration, uniform feed of incinerator, stable operation, complete incineration and decomposition of sulfur slurry;
  • segmented incineration technology can effectively reduce the generation of SO 3 and NO X in the process gas after incineration.
  • the process of the waste heat recovery process includes: the high-temperature SO 2 process gas from the incinerator 32 enters the waste heat boiler 31, and the high-temperature waste heat in the SO 2 process gas is recovered to generate saturated steam of 3.5-4.3 MPa, such as 3.5, 3.6 , 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3 MPa of saturated steam, part of the generated steam is used to heat the oxygen-enriched air for combustion in the incinerator 32, and the rest is sent to the low-pressure steam pipe network after decompression , The desalinated water from the pipe network is sent to the waste heat boiler after dosing and deoxidizing, and the temperature of the SO 2 process gas from the waste heat boiler 31 is reduced to 350-450°C (for example, 350, 360, 370, 380, 390 , 400, 410, 420, 430, 440, 450°C) followed by a purification process.
  • saturated steam such as 3.5, 3.6 , 3.7, 3.8, 3.9
  • Dilute sulfuric acid produced in the purification process with a mass concentration of 0.5%-5% (for example, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4%, 4.5%, 5.0%) is sent to The ammonium sulphate unit is recycled without waste liquid draining.
  • the purification process includes: the SO 2 process gas from the waste heat boiler 31 passes through the humidification tower 29 (primary power wave), the cooling tower 28 (filled tower), the cleaning tower 27 (secondary power wave), and the electrical removal Atomizer A26, for humidification and cooling, cooling and dehydration, washing and purification, and sulfuric acid mist removal, to ensure that the impurities and moisture content in the SO 2 process gas entering the subsequent process meet the process requirements, to prevent the poisoning of the catalyst for the SO 2 conversion process, And maintain the acid production process water balance; and, reduce the temperature of the SO 2 process gas leaving the purification process to 30-48 °C (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 °C), SO 2 process gas is cooled by cooling tower 28 and washing tower 27, and the heat released from the cooling tower is transferred from the cooler outside the tower through cooling water.
  • the humidification tower 29 primary power wave
  • the cooling tower 28 filled tower
  • the cleaning tower 27 secondary
  • a small amount of SO 3 contained in the SO 2 process gas is combined with water during the purification process to produce a mass concentration of 0.5%-5%, for example, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4 %, 4.5%, 5.0%) of the dilute sulfuric acid, finally discharged from the humidifying tower 29, after removing SO 2 through the dilute acid degassing tower A30, it is sent to the saturator of the ammonium sulfate unit of the gas purification plant for use, without waste liquid
  • dilute sulfuric acid is sent to the ammonia absorption tower 12 of the tail gas cleaning process to absorb the ammonia escaping from the tail gas, and no waste liquid is discharged.
  • the technological characteristics of the purification process include, for example:
  • Adopt standard pickling purification process equipped with high-efficiency power sweeping electric defogging purification equipment, high gas purification efficiency, to ensure that the content of harmful impurities in the process gas after purification reaches the required index, and to ensure the activity and life of the catalyst in the conversion process; as well as
  • the process of the drying process includes: the SO 2 process gas from the electric demister A26 in the purification process enters the drying tower 25, and is dried and dehydrated with concentrated H 2 SO 4 with a mass concentration of 93%-95%, and the SO 25 outlet SO 2
  • the water content of the process gas is reduced to ⁇ 0.1g/Nm 3 to meet the requirement of the moisture content of the process gas in the conversion process dry contact acid catalyst; 93%-95% of dry acid is continuously sent from the drying tower 25 to the first In the absorption tower 17, the absorption acid with a mass concentration of about 98% is continuously fed from the first absorption tower 17 to the drying tower 25; and, through the series acid operation of the drying tower 25 and the first absorption tower 17, the dry acid in the drying tower 25 is maintained The required concentration of sulfuric acid absorbed by the sulfuric acid in the drying tower 25 is transferred from the cooler outside the drying tower through the cooling water.
  • the process of the conversion process includes: the conversion process uses a "3+1" 4-stage catalyst bed, secondary conversion, and "III, I-IV, II" heat exchange process flow, and the conversion tower 23 is in order from top to bottom -Stage IV catalyst bed.
  • the SO 2 process gas from the drying tower 25 is pressurized by the SO 2 blower 35, and then passes through the third and first heat exchangers (22, 21) in sequence, and comes out of the catalyst bed of the III and I sections of the SO 2 converter, respectively After the heat of the high-temperature reformed gas reaches about 425°C, it enters the catalyst bed of section I of the SO 2 converter. Under the action of the catalyst, the SO 2 in the process gas reacts with O 2 and is catalytically oxidized to SO 3 .
  • the high-temperature reformed gas coming out of the catalyst bed of stage I undergoes heat exchange and cooling with the low-temperature SO 2 process gas in the first heat exchanger 21, then enters into the catalyst bed of stage II to continue conversion, and then enters into the catalyst bed of the second heat exchanger 19 after cooling and heat exchange.
  • the third stage catalyst bed completes the final catalytic oxidation process of the first SO 2 conversion stage, and finally passes through the third heat exchanger 22, exchanges heat with the low-temperature SO 2 process gas from the SO 2 blower 35, and is sent to the absorption process for first absorption Tower 17.
  • the low-temperature SO 2 process gas from the first absorption tower 17 passes through the IV and II heat exchangers (18, 19), and exchanges heat with the high-temperature conversion gas from the catalytic beds of the SO 2 converter IV and II sections, respectively After that, it enters the catalyst bed of the IV section of the SO 2 converter, performs secondary conversion of SO 2 , and then passes through the heat exchange and temperature reduction of the IV heat exchanger 18, and then is sent to the second absorption tower 16 of the absorption process.
  • the SO 2 catalytic conversion reaction is as follows: SO 2 (g)+1/2O 2 (g) ⁇ SO 3 (g)+100.32 kj/mol.
  • SO 2 gas twice before the conversion process i.e. the process gas into the second SO 2 IV paragraphs I reformer catalyst bed
  • an electric heater 20 for heating up the initial operating stage catalyst used.
  • the technological characteristics of the conversion process include, for example:
  • Incineration adopts oxygen-enriched combustion technology to increase the SO 2 concentration in the process gas entering the SO 2 converter from 5%-5.5% to 7%-12%, which effectively improves the production capacity of the device and saves Construction investment and operating costs;
  • the process of the absorption process includes: the process gas from the conversion process after the first conversion and the second conversion enter the first absorption tower 17 and the second absorption tower 16, respectively, and use a concentration of 98% concentrated H 2 SO 4 SO 3 gas is absorbed, and H 2 O in concentrated sulfuric acid reacts with SO 3 to generate H 2 SO 4 .
  • the SO 3 absorption reaction is as follows: SO 3 (g)+H 2 O(l) ⁇ H 2 SO 4 (l)+134.2 kj/mol.
  • the heat released from the reaction of SO 3 with water in the absorption tower is transferred from the external cooler through the cooling water.
  • a part of the concentrated sulfuric acid generated at the bottom of the first absorption tower 17 with a concentration of 98% is sent to the drying tower 25, and the rest is cooled by the product acid cooler 10 and then sent to the product acid tank 15; and, 94% sulfuric acid from the drying tower 25 is sent
  • the first absorption tower 17 maintains the absorption acid concentration in the first absorption tower 17 through the acid string operation, and the second absorption tower 16 absorbs 98% of sulfuric acid generated by SO 3 into the first absorption tower 17.
  • Each absorption tower is equipped with process soft water make-up pipeline to adjust the absorption acid and product acid concentration.
  • Tail gas washing process tail gas desulfurization technology can use alkali method or ammonia method.
  • the tail gas washing process adopts alkaline desulfurization
  • the acid-making tail gas discharged from the second absorption tower 16 of the absorption process enters the tail gas washing tower 11, and the residual SO 2 and sulfuric acid mist in the tail gas are absorbed by alkali liquid spraying.
  • the tail gas washing process uses ammonia desulfurization
  • the acid-making tail gas discharged from the second absorption tower 16 in the absorption process enters the tail gas washing tower 11, and ammonia water is sprayed to absorb the residual SO 2 and sulfuric acid mist in the tail gas
  • the tail gas discharged from the tail gas scrubber 11 is sent to the ammonia absorption tower 12, and the diluted sulfuric acid solution with a mass concentration of 0.5% to 5% generated in the purification process is used to further absorb the ammonia escaping from the tail gas, and then the tail gas enters the electric demister B13 at high pressure. Under the action of the electric field, the sulfuric acid mist entrained in the exhaust gas is further removed.
  • the clean exhaust gas of the electric demister B13 is finally discharged into the atmosphere through the 30m high chimney 14.
  • the content of harmful substances conforms to the atmosphere in "Emission Standard of Sulfuric Acid Industrial Pollutants" GB26132-2010 Requirements for special discharge limits of pollutants.
  • the ammonium sulfate solution generated in the ammonia absorption tower 12 is sent to the tail gas scrubber 11; and, the excess ammonium sulfite-ammonium sulfate solution in the tail gas scrubber 11 is sent to the raw material pretreatment process to be concentrated together with the filtrate to make sulfur The slurry, or using air to oxidize to ammonium sulfate solution, and then sent to the ammonium sulfate unit to produce ammonium sulfate, no waste liquid discharged.
  • the tail washing process may only be used during the start-up and commissioning phases.
  • the device used in the process for processing coke oven gas desulfurization to produce low-purity sulfur and secondary salt waste liquid includes raw material pretreatment unit, incineration unit, waste heat recovery unit, purification unit, drying unit, conversion unit, absorption unit, exhaust gas cleaning unit,
  • the raw material pretreatment unit, incineration unit, waste heat recovery unit, purification unit, drying unit, conversion unit, absorption unit and exhaust gas cleaning unit are sequentially arranged according to the process flow, wherein the pretreatment slurry output pipeline of the raw material pretreatment unit is connected to the incineration unit Incinerator 32, the outlet pipe of the incinerator 32 is connected to the waste heat boiler 31 of the waste heat recovery unit, the flue gas outlet pipe of the waste heat boiler 31 is connected to the flue gas inlet of the humidification tower 29 of the purification unit, and the electric demister A26 of the purification unit
  • the outlet pipe of the drying unit is connected to the drying tower 25 of the drying unit, the outlet pipe of the converter III stage catalyst bed of the reforming tower 23 in the conversion process is
  • the raw material pretreatment unit includes a foam tank 1, a filtrate tank 3, a slurry tank 4, a centrifuge 5, and a slurry storage tank 6.
  • the outlet line of the foam tank 1 is connected to the inlet of the centrifuge 5 through the pump 2, and the filtrate outlet of the centrifuge 5 is connected
  • the filtrate tank 3, the sulfur paste outlet of the centrifuge 5 is connected to the slurry tank 4, and the outlet of the slurry tank 4 is connected to the slurry storage tank 6.
  • Both the slurry tank 3 and the slurry storage tank 4 are provided with a mechanical stirrer to prevent the sulfur deposit from clogging Equipment and piping.
  • the exhaust gas cleaning unit includes an exhaust gas scrubber 11, an electric demister B13, and a chimney 14.
  • the exhaust gas outlet of the exhaust gas scrubber 11 is connected to the electric demister B13, and the exhaust gas outlet of the electric demister B13 is connected to the chimney 14 .
  • the exhaust gas cleaning unit includes an exhaust gas scrubber 11, an ammonia absorption tower 12, an electric demister B13, and a chimney 14.
  • the exhaust gas outlet of the exhaust gas scrubber 11 is connected to the ammonia absorption tower 12, and the exhaust gas outlet of the ammonia absorption tower 12
  • the flue gas outlet connected to the electric demister B13 and the electric demister B13 is connected to the chimney 14,
  • the coke oven gas treatment capacity of the desulfurization unit of the gas purification device is 150,000 Nm 3 /h
  • the H 2 S content in the coke oven gas before desulfurization is 6 -8g/Nm 3
  • the content of H 2 S in the coke oven gas after desulfurization is 0.02g/Nm 3
  • the content of secondary salt in the desulfurization liquid is 250g/L
  • the catalyst is HPF.
  • This project adopts the technology of "oxygen-enriched combustion, two-to-two absorption" acid production technology to treat coke oven gas HPF desulfurization to produce low-purity sulfur and secondary salt waste liquid.
  • the design sulfuric acid (based on 100% sulfuric acid) output is 105t/d. The process is as follows:
  • the sulfur foam liquid from the sulfur foam tank 1 of the desulfurization unit is sent to a decanter decanter centrifuge 5, after centrifugal separation in solid and liquid phases, the filtrate enters the filtrate tank 3, is pumped out by the filtrate pump, and a part is sent to the concentration tower 8 for concentration , The rest is sent back to the desulfurization unit.
  • the sulfur paste separated from the centrifuge 5 enters the slurry tank 4 and is forcibly mixed with the desulfurized secondary salt concentrate from the concentration tower 8 to obtain a raw material sulfur slurry (see Table 2 for composition), which is sent to the slurry storage tank 6, and then It is sent to the incinerator 32 by the slurry transfer pump.
  • the steam discharged from the concentration tower 8 enters the condensation tower 9 to condense, and the condensate is sent back to the desulfurization unit for use.
  • the non-condensable gas discharged from the condensation tower 9 enters the negative pressure gas pipeline of the gas purification device through the pressure balance system for recovery, and is not discharged outside.
  • Both the slurry tank 4 and the slurry storage tank 6 are equipped with a mechanical stirrer to prevent sulfur deposits from clogging equipment and pipes.
  • the raw material sulfur slurry fed into the incinerator 32 by the raw material pretreatment process is atomized by the compressed air of the waste liquid spray gun process, it is incinerated at 1150°C through two stages of control, and the suspended elemental sulfur and desulfurization vice in the raw material sulfur slurry
  • the sulfur element in the salt is converted into SO 2 ; and, a small amount of SO 3 is still generated.
  • the main chemical incineration and decomposition reactions occurring in the incinerator are as follows:
  • the incinerator 32 is combusted with oxygen-enriched air, and the oxygen concentration in the oxygen-enriched air is 35.3%.
  • the required oxygen-enriched air is prepared by the oxygen-enriched unit through the molecular sieve pressure swing adsorption process, and then sent to the cold air preheater through the oxygen-enriched air blower, heated by the medium-pressure steam produced by waste heat recovery, and then sent to the hot air heater , And heat exchange with the SO 3 process gas from the first section of the converter, after further increasing the temperature, it is finally sent to the first and second combustion chambers of the incinerator for combustion.
  • the concentration of SO 2 in the process gas after incineration is 6.82%-7.59%.
  • the heat required for the combustion of the incinerator is partly supplied by the reaction heat released by the above combustion reaction, and the rest is provided by the combustion-supporting coke oven gas which is sent to the burner in the furnace by the gas pressurizer.
  • the high-temperature SO 2 process gas from the incinerator 32 enters the waste heat boiler 31, and the high-temperature waste heat in the SO 2 process gas is recycled to produce 4.0 MPaG of saturated steam, and part of the generated steam is used for the cold air preheater to heat the incinerator Oxygen-enriched air for internal combustion, the rest is depressurized to 0.7MPaG and then sent to the low-pressure steam pipe network.
  • the desalinated water from the pipe network is sent to the waste heat boiler after dosing and deoxidizing treatment, and the SO from the waste heat boiler 2 Purify the process after the process gas temperature drops to 350°C.
  • the SO 2 process gas from the waste heat boiler 31 passes through the humidification tower 29 (primary power wave), the cooling tower 28 (filler tower), the cleaning tower 27 (secondary power wave), and the electric demister A26 for humidification Cooling, cooling and dehydration, washing and purification, and sulfuric acid mist removal to ensure that the impurities and moisture content of the SO 2 process gas entering the subsequent process meet the process requirements, to prevent the poisoning of the catalyst used in the SO 2 conversion process, and to keep the acid process water balance .
  • the temperature of the SO 2 process gas leaving the purification process is reduced to 48° C.
  • the heat released by the SO 2 process gas after cooling and cooling through the cooling tower 28 and the washing tower 27 is transferred from the cooler outside the tower through cooling water.
  • a small amount of SO 3 contained in the SO 2 process gas combines with water during the purification process to produce a dilute sulfuric acid with a concentration of about 2.1%, and is finally discharged from the humidification tower 29.
  • the SO 2 is removed by the dilute acid degassing tower A30 and cooled, it is sent It is used in the saturator of the ammonium sulfide unit of the gas purification device, and no waste liquid is discharged.
  • the SO 2 process gas from the electric demister A26 in the purification process enters the drying tower 25, and is dried and dehydrated with concentrated H 2 SO 4 with a mass concentration of 94%.
  • the water content of the SO 2 process gas at the outlet of the drying tower 25 is reduced to 0.1 g /Nm 3 to meet the requirement of moisture content in the process gas of the acid catalyst produced by the dry contact method in the conversion process.
  • 94% of the dry acid is continuously sent from the drying tower 25 to the first absorption tower 17 circulation tank; from the first absorption tower 17 circulation tank to the drying tower 25 circulation tank, the absorption acid with a mass concentration of 98% is continuously fed.
  • the required concentration of the dry acid in the drying tower 25 is maintained by the string acid operation of the drying tank 25 circulation tank and the first absorption tower 17 circulation tank.
  • the heat released by the sulfuric acid absorbing moisture in the drying tower 25 is transferred from the outer cooler of the drying tower 25 through the cooling water.
  • the conversion process uses "3+1" 4-stage catalyst bed, secondary conversion, and "III, I-IV, II” heat exchange process.
  • the high-temperature reformed gas coming out of the catalyst bed of stage I exchanges heat with the oxygen-enriched air from the cold air afterheater and the low-temperature SO 2 process gas through the hot air heater and the first heat exchanger 21 respectively, and then enters the catalyst bed of stage II
  • the catalyst bed of stage II Continue the conversion, and then after passing through the second heat exchanger 19 to reduce the temperature, enter the III stage catalyst bed, complete the final catalytic oxidation process of the SO 2 conversion stage, and finally pass the third heat exchanger 22, and the low temperature from the SO 2 fan
  • the SO 2 process gas is sent to the first absorption tower 17 of the absorption process after being cooled by heat exchange.
  • the low-temperature SO 2 process gas from the first absorption tower 17 passes through the IV and II heat exchangers (18, 19), and exchanges heat with the high-temperature conversion gas from the catalytic beds of the SO 2 converter IV and II sections, respectively After that, it enters into the catalyst bed of the IV section of the SO 2 converter, performs the secondary conversion of SO 2 , and then passes through the heat exchange and cooling of the IV heat exchanger, and then is sent to the second absorption tower in the absorption process.
  • the SO 2 catalytic conversion reaction is as follows: SO 2 (g)+1/2O 2 (g) ⁇ SO 3 (g)+100.32 kj/mol.
  • SO 2 gas twice before the conversion process i.e. the process gas into the second SO 2 IV paragraphs I reformer catalyst bed
  • an electric heater 20 for heating up the initial operating stage catalyst used.
  • the process gas from the primary conversion and secondary conversion from the conversion process enters the first absorption tower 17 and the second absorption tower 16, respectively, and absorbs the SO 3 gas therein with 98% concentrated H 2 SO 4 .
  • H 2 O and SO 3 react to form H 2 SO 4 .
  • the SO 3 absorption reaction is as follows: SO 3 (g)+H 2 O(l) ⁇ H 2 SO 4 (l)+134.2 kj/mol.
  • the heat released from the reaction of SO 3 with water in the absorption tower is transferred from the external cooler through the cooling water.
  • a part of the 98% concentrated sulfuric acid generated at the bottom of the first absorption tower 17 is sent to the drying tower 25, and the rest is cooled by the product acid cooler and sent to the product acid tank 15; 94% sulfuric acid from the drying tower 25 is sent to the first absorption tower 17 for circulation
  • the absorption acid concentration in the first absorption tower 17 is maintained by the string acid operation
  • the second absorption tower 16 absorbs 98% of sulfuric acid generated by SO 3 into the circulation tank of the first absorption tower 17.
  • Each absorption tower circulation tank is equipped with process soft water make-up pipeline to adjust the absorption acid and product acid concentration.
  • the tail gas cleaning process adopts ammonia desulfurization
  • the acid-making tail gas discharged from the second absorption tower 16 enters the tail gas washing tower 11, and the residual ammonia water is used to spray and absorb the residual residue in the tail gas, which is originally sent to the biochemical treatment of alkaline steamed ammonia wastewater
  • the SO 2 and sulfuric acid mist then enter the electric demister B13. Under the action of a high-voltage electric field, the sulfuric acid mist entrained in the exhaust gas is further removed.
  • the clean exhaust gas from the electric demister B13 is finally discharged into the atmosphere through the 30m high chimney 14.
  • the distilled ammonia wastewater discharged from the tail gas washing tower 11 is sent back to the phenol cyanide wastewater treatment device for treatment.
  • the project was successfully put into operation on December 25, 2017.
  • the main technical indicators and main environmental indicators detected by the owner are as follows:
  • Acid-making exhaust gas about 7000Nm 3 /h, unit product baseline exhaust volume of 1950Nm/t; of which harmful substance content: SO 2 content: 95mg/Nm 3 ; sulfuric acid mist: undetectable; NO X : 125mg/Nm 3 ; description : The emission limits of harmful substances in the exhaust gas of sulphuric acid industry specified in GB26132-2010:
  • the coke oven gas treatment capacity of the desulfurization unit of the gas purification device is 88000Nm 3 /h
  • the H 2 S content in the coke oven gas before desulfurization is 8-10g/Nm 3
  • the content of H 2 S in coke oven gas is 0.02 g/Nm 3
  • the content of secondary salt in the desulfurization liquid is 250 g/L
  • the catalyst is HPF.
  • the designed sulfuric acid (based on 100% sulfuric acid) output is 65.5t/d.
  • the rest are the same as the process flow of the low-quality sulfur paste and desulfurization liquid secondary salt resource utilization project of Example 1.
  • the oxygen concentration in the oxygen-enriched air in the incineration process is 38.5%.
  • the process and device for processing coke oven gas desulfurization to produce low-purity sulfur and secondary salt waste liquid can be used in industry in batches, completely solving the low-purity sulfur recovery and desulfurization generated by the coke oven gas ammonia wet oxidation desulfurization process
  • the use of oxygen-enriched combustion technology can effectively reduce the amount of process gas and increase the concentration of SO 2 in the process gas, save construction investment and operating costs, and ensure the self-heat balance of the two-to-two-suction technology.
  • the second conversion and second absorption technology has been used to increase the SO 2 conversion rate from 97.5% to more than 99.9%, which significantly improves the sulfur recovery rate.
  • the sulfuric acid produced by it can be used as a raw material for the production of ammonium sulfate from the deamination of coke oven gas.
  • the SO 2 content in the exhaust gas after the absorption process is reduced, which achieves the dual goals of recycling the sulfur resources and improving the level of environmental protection.

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Abstract

提供一种处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置。该工艺包括原料预处理工序、焚烧工序、余热回收工序、净化工序、干燥工序、转化工序、吸收工序、尾气洗净工序，其中焚烧工序采用富氧空气燃烧，转化工序和吸收工序分别采用二次转化和二次吸收。该装置包括按照工艺依次设置的原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元和尾气洗净单元。该工艺和装置能有效降低工艺气量和提高工艺气中SO 2浓度，节省建设投资及运行成本，保证二转二吸技术的自热平衡；将SO 2转化率从97.5％提高到99.9％以上，显著提高硫的回收率，大幅降低吸收工序后尾气中SO 2含量，并提高工艺环保水平。

Description

处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置
相关申请的交叉引用
本公开要求于2018年12月27日提交中国专利局的申请号为201811607585.8、名称为“处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本公开涉及焦化行业含硫废液焚烧制酸技术领域，具体地涉及一种处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置，其采用“富氧燃烧、二转二吸”制酸技术，并适用于处理焦炉煤气氨法湿式氧化脱硫工艺产生的低品质硫磺及脱硫副盐废液。
背景技术
目前，焦化行业较多采用以HPF、PDS等为催化剂的氨法湿式氧化脱硫工艺脱除煤气中的H 2S和HCN。
尽管上述脱硫工艺脱硫脱氰效率较高，但从煤气中脱除H 2S后生成的副产品硫磺，由于含有煤粉、焦油、萘等杂质，产品纯度低，市场销售困难。为避免形成焦化固废，影响环境，目前低品质硫磺多数以低价售出或免费送给用户使用，硫资源未能得到有效、合理利用，未能产生应有的价值。
此外，上述脱硫工艺在脱硫脱氰过程中产生了硫氰酸铵及硫代硫酸铵等副盐废液。当系统中副盐浓度积累较高时，则会严重影响煤气脱硫脱氰效率，并加剧设备腐蚀。目前采用的副盐废液处理工艺有：①废液兑入炼焦配煤，送焦炉焚烧分解；以及，②提取硫氰酸铵及硫代硫酸铵副盐。生产实践表明：将副盐废液兑入炼焦配煤，送焦炉焚烧分解工艺，由于废液在兑入炼焦配煤过程中，溶解于废液中的氨等有害气体挥发排放到大气中，造成环境污染而使其应用受到限制；而采取提取硫氰酸铵及硫代硫酸铵副盐工艺，则由于副盐产品市场容量小、副盐产品销售困难，特别是硫代硫酸铵市场无需求，形成新的焦化固废，带来后续环保问题。由于存在以上问题，使目前采用的上述脱硫废液处理工艺在实际中受到了限制，导致目前多数脱硫装置中副盐浓度控制在较高水平，这影响了脱硫装置性能的正常发挥以及焦化环保水平的提高。
根据专利和文献检索：专利申请号为201610736196.X公开的“一种利用煤气湿式氧化法产生的含硫废液制取硫酸的方法”、专利申请号为201610777877.0公开的“含硫废液焚 烧制硫酸的方法”、上海宝钢从日本引进的“昆帕克斯(COMPACS)废液焚烧制酸技术”，均是采用“空气燃烧、一转一吸”的制酸工艺；以及，专利申请号为201310524911.X公开的“一种含硫废液干法制酸系统及方法”、专利申请号为201810232542.X公开的“一种湿式氧化脱硫废液制硫酸工艺及装置”，均是采用“空气燃烧、二转二吸”的制酸工艺。
发明内容
本公开提供了一种采用“富氧燃烧、二转二吸”制酸技术处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置，从根本上一次性彻底解决了焦炉煤气氨法湿式氧化脱硫工艺产生的低纯硫磺回收利用及脱硫副盐废液无害化处理等问题，提高了硫的回收率，其生产的硫酸可用做焦炉煤气脱氨生产硫酸铵的原料，这实现了硫资源的循环利用和环境保护的双重目标。
为了达到至少上述目的，本公开一方面提供了一种处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其工艺流程包括原料预处理工序、焚烧工序、余热回收工序、净化工序、干燥工序、转化工序、吸收工序、尾气洗净工序，其中焚烧工序采用富氧空气燃烧，转化工序和吸收工序则采用二次转化、二次吸收。
在一种或多种实施方式中，原料预处理工序采用沉降离心分离及浓缩技术对煤气脱硫工艺产生的硫泡沫液进行处理。
在一种或多种实施方式中，原料预处理工序的工艺过程包括：将来自脱硫单元硫泡沫槽的硫泡沫液送入卧式离心机，经固、液两相离心分离后，滤液进入滤液槽，然后用滤液泵抽出，一部分送往浓缩塔，其余送回脱硫单元的脱硫塔；从离心机分出的硫膏进入浆液槽，与来自浓缩塔的脱硫副盐浓缩液强制混合均匀，制得原料硫浆，送至浆液贮槽，然后再由浆液移送泵送往焚烧炉；浓缩塔排出的蒸汽进入凝缩塔冷凝，凝缩液送回脱硫单元的脱硫塔使用；凝缩塔排出的不凝性气体进入煤气净化装置的负压煤气管道。
在一种或多种实施方式中，原料预处理工序全部在密闭设备及管道内完成。
在一种或多种实施方式中，焚烧工序的工艺过程包括：将由原料预处理工序送入焚烧炉的原料硫浆，经废液喷枪用工艺压缩空气雾化后，在1050-1250℃温度下，通过分段(例如，两段)控制富氧焚烧技术，将原料硫浆中的悬浮单质硫和脱硫副盐中的硫元素转化为SO 2。
在一种或多种实施方式中，富氧空气中氧气浓度为25％-45％。
在一种或多种实施方式中，富氧空气由直接供给的纯氧和燃烧用空气混合制得或者采用分子筛变压吸附工艺制得。
在一种或多种实施方式中，将净化工序产生的质量浓度为0.5％-5％的稀硫酸送至硫铵 单元回收利用，无废液外排。
在一种或多种实施方式中，转化工序采用“3+1”4段催化剂床、二次转化，及“III、I-IV、II”换热工艺流程，转化塔从上至下依次为I段-IV段催化剂床。
在一种或多种实施方式中，转化工序所采用的“3+1”4段催化剂床、二次转化为干接触法。
在一种或多种实施方式中，SO 2工艺气进入转化器第I段及第IV段催化剂床前，在初始开工阶段对催化剂进行加热升温。
在一种或多种实施方式中，吸收工序的工艺过程包括：来自转化工序的一次转化及二次转化后的工艺气分别进入第一吸收塔及第二吸收塔。
在一种或多种实施方式中，尾气洗净工序采用碱法脱硫，其包括：从吸收工序排出的制酸尾气进入尾气洗涤塔，采用碱液喷淋吸收尾气中残余的SO 2和硫酸雾，尾气洗涤塔内多余的吸收液送至生化单元进行处理。
在一种或多种实施方式中，尾气洗净工序采用氨法脱硫，其包括：从吸收工序排出的制酸尾气进入尾气洗涤塔，采用氨水喷淋吸收尾气中残余的SO 2和硫酸雾；
将尾气洗涤塔排出的尾气送入氨吸收塔，以进一步吸收尾气中逃逸的氨；
将氨吸收塔内生成的硫酸铵溶液送至尾气洗涤塔；以及
将尾气洗涤塔内多余的亚硫酸铵-硫酸铵溶液送至原料预处理工序随同滤液一起进行浓缩，制成硫浆，或者利用空气氧化成硫酸铵溶液，再送至硫铵单元制取硫酸铵，无废液外排。
本公开的另一方面提供了如本公开提供的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，其包括原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元、尾气洗净单元，原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元和尾气洗净单元按照工艺流程依次设置，其中原料预处理单元的预处理浆液输出管路连接焚烧单元的焚烧炉，焚烧炉的出口管路连接余热回收单元的废热锅炉，废热锅炉的烟气出口管路连接净化单元的增湿塔的烟气入口，净化单元的电除雾器A的出口管路连接干燥单元的干燥塔，转化工序中转化塔的转化器III段催化剂床出口管路连接吸收工序的第一吸收塔，第一吸收塔的烟气出口管路连接转化塔的转化器IV段催化剂床入口，转化塔的转化器IV段催化剂床出口管路连接吸收工序的第二吸收塔，第二吸收塔的出口管路连接尾气洗净单元的尾气洗涤塔，第一吸收塔底部的硫酸出口管路连接干燥单元的干燥塔。
在一种或多种实施方式中，原料预处理单元包括泡沫槽、滤液槽、浆液槽、离心机、浆液贮槽，泡沫槽的出口管路通过泵连接离心机的入口，离心机的滤液出口连接滤液槽， 离心机的硫膏出口连接浆液槽，浆液槽的出口连接浆液贮槽，在浆液槽和浆液贮槽中均设有机械搅拌器。
在一种或多种实施方式中，尾气洗净单元包括尾气洗涤塔、电除雾器B、烟囱，尾气洗涤塔的烟气出口连接电除雾器B，电除雾器B的烟气出口连接烟囱。
在一种或多种实施方式中，尾气洗净单元包括尾气洗涤塔、氨吸收塔、电除雾器B、烟囱，尾气洗涤塔的烟气出口连接氨吸收塔，氨吸收塔的烟气出口连接电除雾器B，电除雾器B的烟气出口连接烟囱，氨吸收塔的硫酸铵溶液出口连接尾气洗涤塔，尾气洗涤塔的亚硫酸铵-硫酸铵溶液出口连接原料预处理单元的浓缩塔。
在一种或多种实施方式中，第一吸收塔和第二吸收塔均设有工艺软水补入管线。
本公开提供的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置实现的有益效果包括，例如：
本公开焚烧工序采用“富氧燃烧、二转二吸”制酸技术处理焦炉煤气脱硫产低纯硫磺及副盐废液，富氧燃烧技术有效降低工艺气量和提高工艺气中SO 2浓度，节省建设投资及运行成本，保证二转二吸技术的自热平衡；以及
转化工序和吸收工序采用二转二吸技术，将SO 2转化率从97.5％提高到99.9％以上，显著提高了硫的回收率，大幅降低了吸收工序后尾气中SO 2含量，并提高了工艺环保水平。
附图说明
图1是根据本公开一种实施方式提供的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺流程示意图(尾气洗净工序采用碱法脱硫)。
图2是根据本公开另一种实施方式提供的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺流程示意图(尾气洗净工序采用氨法脱硫)。
在图中：1-泡沫槽、2-泵、3-滤液槽、4-浆液槽、5-离心机、6-浆液贮槽、7-加热器、8-浓缩塔、9-凝缩塔、10-冷却器、11-尾气洗涤塔、12-氨吸收塔、13-电除雾器B、14-烟囱、15-产品酸槽、16-第二吸收塔、17-第一吸收塔、18-第IV换热器、19-第II换热器、20-电加热器、21-第I换热器、22-第III换热器、23-转化塔、24-脱气塔B、25-干燥塔、26-电除雾器A、27-洗净塔、28-冷却塔、29-增湿塔、30-脱气塔A、31-废热锅炉、32-焚烧炉、33-鼓风机、34-雾化风机、35-SO 2风机。
具体实施方式
下面结合具体实施方式对本公开的内容作进一步的详细说明，但不应将此理解为本公开的范围仅限于以下的实例。在不脱离本公开上述技术思想的情况下，根据本领域普通技 术知识和常用技术手段做出的各种替换或变更，均应包括在本公开的范围内。
如图1、图2所示，处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，工艺流程包括原料预处理工序、焚烧工序、余热回收工序、净化工序、干燥工序、转化工序、吸收工序、尾气洗净工序，其中焚烧工序采用富氧空气燃烧，转化工序和吸收工序则采用二次转化、二次吸收。
原料预处理工序的工艺过程包括：将来自脱硫单元硫泡沫槽1的硫泡沫液送入卧式离心机5，经固、液两相离心分离后，滤液进入滤液槽3，然后用滤液泵抽出，一部分送往浓缩塔8，其余送回脱硫单元的脱硫塔；从离心机5分出的硫膏进入浆液槽4，与来自浓缩塔8的脱硫副盐浓缩液强制混合均匀，制得原料硫浆，送至浆液贮槽6，然后再由浆液移送泵送往焚烧炉32；浓缩塔8排出的蒸汽进入凝缩塔9冷凝，凝缩液送回脱硫单元的脱硫塔使用；凝缩塔9排出的不凝性气体进入煤气净化装置的负压煤气管道。
硫浆的具体组成，见表1。
表1 硫浆组成
悬浮单质硫 w％ 10％-20％
NH 4SCN w％ 6％-20％
(NH 4) 2S 2O 3 w％ 3.5％-20％
(NH 4) 2SO 4 w％ 1％-5％
(NH 4) 2S 6 w％ 0.05％-3.5％
(NH 4) 2CO 3 w％ 0.1％-2.0％
NH 3 w％ 0.05％-0.5％
H 2O w％ 45％-70％
原料预处理工序的工艺特点包括，例如：
(1)采用沉降离心分离及浓缩技术对煤气脱硫工艺产生的硫泡沫液进行处理，可有效将脱硫单元产生的悬浮单质硫及脱硫副盐废液从系统中连续稳定分出，制得所需原料硫浆，使脱硫液中悬浮硫及副盐含量控制在较低水平，保证了脱硫单元长期稳定运行以及制酸原料硫浆组成稳定；以及
(2)原料预处理操作全部在密闭设备及管道内完成，工艺流程短，占地小，自动化水平高，操作安全、稳定、环保。
焚烧工序的工艺过程包括：将由原料预处理工序送入焚烧炉32的原料硫浆经废液喷枪用工艺压缩空气雾化后，在1050-1250℃温度下，例如1050、1100、1150、1120、1125℃，通过分段控制富氧焚烧技术，将原料硫浆中的悬浮单质硫和脱硫副盐中的硫元素转化为SO 2；以及，尚有少量SO 3生成。焚烧炉32内发生的主要化学焚烧、分解反应包括如下：
1)S+O 2→SO 2
2)NH 4SCN+O 2→N 2+CO 2+SO 2+H 2O
3)(NH 4) 2S 2O 3+O 2→N 2+SO 2+H 2O
4)(NH 4) 2SO 4+O 2→N 2+SO 2+H 2O
5)(NH 4) 2S 6+O 2→N 2+SO 2+H 2O
6)(NH 4) 2CO 3+O 2→N 2+CO 2+H 2O
7)NH 3+O 2→N 2+H 2O
8)SO 2+O 2→SO 3
焚烧炉32内采用富氧空气燃烧，富氧空气中氧气浓度为25％-45％，例如25％、30％、35％、40％、45％。所需富氧空气，可由直接供给的纯氧和燃烧用空气混合制得，也可采用分子筛变压吸附工艺制得，然后经富氧空气鼓风机33送至加热器，用蒸汽加热升温后，送至焚烧炉32分段燃烧室供燃烧使用。
焚烧炉32燃烧所需热量部分由上述燃烧反应放出的反应热供给，其余部分由煤气加压机送入炉内燃烧器燃烧的助燃焦炉煤气提供。
焚烧工序的工艺特点包括，例如：
(1)采用悬浮单质硫与浓缩废液配制而成的硫浆流态化进料，空气雾化焚烧，焚烧炉进料均匀，操作稳定，硫浆焚烧、分解完全；
(2)采用富氧焚烧技术，有效降低工艺气量，并将焚烧后工艺气中SO 2浓度由4％-4.2％提高至6.5％-8％，从而间接提高进SO 2转化器的工艺气中SO 2浓度，节省建设投资及运行成本，保证二转二吸技术的自热平衡；以及
(3)采用分段控制焚烧技术，可有效减少焚烧后工艺气中SO 3及NO X的生成。
余热回收工序的工艺过程包括：从焚烧炉32出来的高温SO 2工艺气进入废热锅炉31，对SO 2工艺气中的高温余热进行回收利用，产生3.5-4.3MPa的饱和蒸汽，例如3.5、3.6、3.7、3.8、3.9、4.0、4.1、4.2、4.3MPa的饱和蒸汽，产生的蒸汽部分用于加热焚烧炉32内燃烧用的富氧空气，其余部分经减压后送至低压蒸汽管网使用，来自管网的除盐水经加药及脱氧处理后送入废热锅炉，将从废热锅炉31出来的SO 2工艺气的温度降至350-450℃(例如，350、360、370、380、390、400、410、420、430、440、450℃)后进行净化工序。
净化工序产生的质量浓度为0.5％-5％(例如，0.5％、1.0％、1.5％、2.0％、2.5％、3.0％、3.5％、4％、4.5％、5.0％)的稀硫酸送至硫铵单元回收利用，无废液外排。
净化工序的工艺过程包括：来自废热锅炉31的SO 2工艺气依次通过增湿塔29(一级动力波)、冷却塔28(填料塔)、洗净塔27(二级动力波)及电除雾器A26，进行增湿降温、冷却脱水、洗涤净化及硫酸雾脱除，保证进入后续工序的SO 2工艺气中的杂质及水分含量达到工艺要求指标，以防止SO 2转化工艺用催化剂中毒，并保持制酸工艺水平衡；以及，将离开净化工序的SO 2工艺气的温度降至30-48℃(30、31、32、33、34、35、36、37、38、39、40、41、42、43、44、45、46、47、48℃)，SO 2工艺气经冷却塔28及洗净塔27冷却降温所放出的热量由塔外冷却器通过冷却水转移。
SO 2工艺气中含有的少量SO 3在净化过程中与水结合生成质量浓度为0.5％-5％例如，0.5％、1.0％、1.5％、2.0％、2.5％、3.0％、3.5％、4％、4.5％、5.0％)的稀硫酸，最终从增湿塔29排出，经稀酸脱气塔A30脱除SO 2后，送至煤气净化车间硫铵单元的饱和器使用，无废液外排；当尾气洗净工序采用氨法脱硫时，稀硫酸送至尾气洗净工序的氨吸收塔12，吸收尾气中逃逸的氨，无废液外排。
净化工序的工艺特点包括，例如：
(1)采用标准酸洗净化工艺，配以高效动力波及电除雾净化设备，气体净化效率高，可确保净化后工艺气中的有害杂质含量达到要求指标，保证转化工序催化剂活性及寿命；以及
(2)产生的质量浓度为0.5％-5％的稀硫酸送至硫铵单元回收利用，无废液、废渣外排；尾气洗净工序采用氨法脱硫时，稀硫酸送至尾气洗净工序，无废液外排。
干燥工序的工艺过程包括：从净化工序电除雾器A26出来的SO 2工艺气进入干燥塔25，用质量浓度为93％-95％的浓H 2SO 4进行干燥脱水，干燥塔25出口SO 2工艺气的含水量降至≤0.1g/Nm 3，以满足转化工序干接触法制酸催化剂对工艺气中水分含量的要求；从干燥塔25连续送出93％-95％的干燥酸进入第一吸收塔17，从第一吸收塔17向干燥塔25连续送入质量浓度约98％的吸收酸；以及，通过干燥塔25与第一吸收塔17的串酸操作，维持干燥塔25内干燥酸的所需浓度，干燥塔25内硫酸吸收水分放出的热量由干燥塔外冷却器通过冷却水转移。
转化工序的工艺过程包括：转化工序采用“3+1”4段催化剂床、二次转化，及“III、I-IV、II”换热工艺流程，转化塔23从上至下依次为I段-IV段催化剂床。
从干燥塔25出来的SO 2工艺气经SO 2风机35加压后，依次通过第III、第I换热器(22、21)，分别与从SO 2转化器III段及I段催化剂床出来的高温转化气换热至约425℃后，进入SO 2转化器I段催化剂床，在催化剂作用下，工艺气中的SO 2与O 2反应，被催化氧化为SO 3。从I段催化剂床出来的高温转化气经第I换热器21与低温SO 2工艺气换热降温后，进入II段催化剂床继续转化，然后经第II换热器19换热降温后，进入III段催化剂床，完成SO 2一次转化阶段的最后催化氧化过程，最后经第III换热器22，与来自SO 2风机35的低温SO 2工艺气换热降温后，送至吸收工序第一吸收塔17。从第一吸收塔17出来的低温SO 2工艺气经第IV、第II换热器(18、19)，分别与从SO 2转化器IV段及II段催化床层出来的高温转化气换热后，进入SO 2转化器IV段催化剂床，进行SO 2的二次转化，然后经第IV换热器18换热降温后，送至吸收工序第二吸收塔16。SO 2催化转化反应如下：SO 2(g)+1/2O 2(g)→SO 3(g)+100.32kj/mol。
SO 2工艺气两次转化前，即SO 2工艺气进入转化器第I段及第IV段催化剂床前，均设 有电加热器20，用于初始开工阶段催化剂加热升温使用。
转化工序的工艺特点包括，例如：
(1)焚烧采用的是富氧燃烧技术，将进SO 2转化器的工艺气中的SO 2浓度由5％-5.5％提高至7％-12％，有效提高了装置的生产能力，节省了建设投资及运行成本；以及
(2)采用干接触法“3+1”二次转化工艺，技术先进，工艺成熟可靠，可将SO 2最终转化率从97.5％提高到99.9％以上，大幅降低了转化后尾气中SO 2含量。
吸收工序的工艺过程包括：来自转化工序的一次转化及二次转化后的工艺气分别进入第一吸收塔17及第二吸收塔16，用质量浓度为98％的浓H 2SO 4对其中的SO 3气体进行吸收，浓硫酸中的H 2O与SO 3反应生成H 2SO 4。SO 3吸收反应如下：SO 3(g)+H 2O(l)→H 2SO 4(l)+134.2kj/mol。
吸收塔内SO 3与水反应放出的热量由外冷却器通过冷却水转移。第一吸收塔17底部生成的质量浓度为98％浓硫酸一部分送至干燥塔25，其余经产品酸冷却器10冷却后送入产品酸槽15；以及，来自干燥塔25的94％硫酸送入第一吸收塔17，通过串酸操作维持第一吸收塔17内吸收酸浓度，第二吸收塔16吸收SO 3产生的98％硫酸进入第一吸收塔17。各吸收塔均设有工艺软水补入管线，以调节吸收酸及产品酸浓度。
尾气洗净工序：尾气脱硫技术可采用碱法，也可以采用氨法。
如图1所示，尾气洗净工序采用碱法脱硫，从吸收工序第二吸收塔16排出的制酸尾气进入尾气洗涤塔11，采用碱液喷淋吸收尾气中残余的SO 2和硫酸雾，然后进入电除雾器B13，在高压电场作用下，进一步脱除尾气中夹带的硫酸雾，出电除雾器B13的洁净尾气最后经30m高烟囱14排入大气，其中有害物含量符合《硫酸工业污染物排放标准》GB26132-2010中大气污染物特别排放限制的要求；尾气洗涤塔11内多余的吸收液送至生化单元进行处理。
如图2所示，尾气洗净工序采用氨法脱硫，从吸收工序第二吸收塔16排出的制酸尾气进入尾气洗涤塔11，采用氨水喷淋吸收尾气中残余的SO 2和硫酸雾；将尾气洗涤塔11排出的尾气送入氨吸收塔12，采用净化工序产生的质量浓度为0.5％-5％的稀硫酸溶液进一步吸收尾气中逃逸的氨，然后尾气进入电除雾器B13，在高压电场作用下，进一步脱除尾气中夹带的硫酸雾，出电除雾器B13的洁净尾气最后经30m高烟囱14排入大气，有害物含量符合《硫酸工业污染物排放标准》GB26132-2010中大气污染物特别排放限制的要求。
氨吸收塔12内生成的硫酸铵溶液，送至尾气洗涤塔11；以及，尾气洗涤塔11内多余的亚硫酸铵-硫酸铵溶液，送至原料预处理工序随同滤液一起进行浓缩，制成硫浆，或者利用空气氧化成硫酸铵溶液，再送至硫铵单元制取硫酸铵，无废液外排。
对于不在执行大气污染物特别排放限值区域内的企业，尾洗工序可以仅在开工和调试 阶段使用。
处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，包括原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元、尾气洗净单元，原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元和尾气洗净单元按照工艺流程依次设置，其中原料预处理单元的预处理浆液输出管路连接焚烧单元的焚烧炉32，焚烧炉32的出口管路连接余热回收单元的废热锅炉31，废热锅炉31的烟气出口管路连接净化单元的增湿塔29的烟气入口，净化单元的电除雾器A26的出口管路连接干燥单元的干燥塔25，转化工序中转化塔23的转化器III段催化剂床出口管路连接吸收工序的第一吸收塔17，第一吸收塔17的烟气出口管路连接转化塔23的转化器IV段催化剂床入口，转化塔23的转化器IV段催化剂床出口管路连接吸收工序的第二吸收塔16，第二吸收塔16的出口管路连接尾气洗净单元的尾气洗涤塔11，第一吸收塔17底部的硫酸出口管路连接干燥单元的干燥塔25。
原料预处理单元包括泡沫槽1、滤液槽3、浆液槽4、离心机5、浆液贮槽6，泡沫槽1的出口管路通过泵2连接离心机5的入口，离心机5的滤液出口连接滤液槽3，离心机5的硫膏出口连接浆液槽4，浆液槽4的出口连接浆液贮槽6，在浆液槽3和浆液贮槽4中均设有机械搅拌器，以防止硫磺沉积而堵塞设备及管道。
见图1，尾气洗净单元包括尾气洗涤塔11、电除雾器B13、烟囱14，尾气洗涤塔11的烟气出口连接电除雾器B13，电除雾器B13的烟气出口连接烟囱14。
见图2，尾气洗净单元包括尾气洗涤塔11、氨吸收塔12、电除雾器B13、烟囱14，尾气洗涤塔11的烟气出口连接氨吸收塔12，氨吸收塔12的烟气出口连接电除雾器B13、电除雾器B13的烟气出口连接烟囱14，氨吸收塔12的硫酸铵溶液出口连接尾气洗涤塔11，尾气洗涤塔11的亚硫酸铵-硫酸铵溶液出口连接原料预处理单元的浓缩塔8。
实施例1：
以山东某公司低品质硫膏和脱硫液副盐资源化利用工程为例：煤气净化装置脱硫单元的焦炉煤气处理量为150000Nm 3/h，脱硫前焦炉煤气中的H 2S含量为6-8g/Nm 3，脱硫后焦炉煤气中H 2S含量为0.02g/Nm 3，脱硫液中副盐的含量为250g/L，催化剂为HPF。本工程采用“富氧燃烧、二转二吸”制酸技术处理焦炉煤气HPF脱硫产低纯硫磺及副盐废液的工艺，设计硫酸(按100％硫酸计)产量为105t/d，工艺流程如下：
原料预处理工序：
将来自脱硫单元硫泡沫槽1的硫泡沫液送入卧螺沉降式离心机5，经固、液两相离心分离后，滤液进入滤液槽3，经滤液泵抽出，一部分送往浓缩塔8浓缩，其余送回脱硫单元。从离心机5分出的硫膏进入浆液槽4，与来自浓缩塔8的脱硫副盐浓缩液强制混合均匀， 制得原料硫浆(组成见表2)，送至浆液贮槽6，然后再由浆液移送泵送往焚烧炉32。
浓缩塔8排出的蒸汽进入凝缩塔9冷凝，凝缩液送回脱硫单元使用。凝缩塔9排出的不凝性气体通过压力平衡系统进入煤气净化装置的负压煤气管道回收，不外排。
浆液槽4及浆液贮槽6均设有机械搅拌器，以防止硫磺沉积而堵塞设备及管道。
表2 实施例1的硫浆组成
悬浮单质硫 w％ 14％-16％
NH 4SCN w％ 15％-18％
(NH 4) 2S 2O 3 w％ 10％-12％
(NH 4) 2SO 4 w％ 2.5％-3.5％
(NH 4) 2S 6 w％ 0.1％-0.2％
(NH 4) 2CO 3 w％ 0.5％-1.0％
NH 3 w％ 0.05％-0.08％
H 2O w％ 55％-65％
焚烧工序：
将由原料预处理工序送入焚烧炉32的原料硫浆经废液喷枪用工艺压缩空气雾化后，在1150℃温度下，通过两段控制焚烧，将原料硫浆中的悬浮单质硫和脱硫副盐中的硫元素转化为SO 2；以及，尚有少量SO 3生成。焚烧炉内发生的主要化学焚烧、分解反应如下：
1)S+O 2→SO 2
2)NH 4SCN+O 2→N 2+CO 2+SO 2+H 2O
3)(NH 4) 2S 2O 3+O 2→N 2+SO 2+H 2O
4)(NH 4) 2SO 4+O 2→N 2+SO 2+H 2O
5)(NH 4) 2S 6+O 2→N 2+SO 2+H 2O
6)(NH 4) 2CO 3+O 2→N 2+CO 2+H 2O
7)NH 3+O 2→N 2+H 2O
8)SO 2+O 2→SO 3
焚烧炉32内采用富氧空气燃烧，富氧空气中氧气浓度为35.3％。所需富氧空气由富氧机组通过分子筛变压吸附工艺制得，然后经富氧空气鼓风机先送至冷空气预热器，采用余热回收自产的中压蒸汽加热，再送至热空气加热器，和转化器I段出来的SO 3工艺气换热，进一步升温后，最终送焚烧炉一段燃烧室及二段燃烧室燃烧使用。焚烧后工艺气中SO 2浓度为6.82％-7.59％。
焚烧炉燃烧所需热量部分由上述燃烧反应放出的反应热供给，其余部分由煤气加压机送入炉内燃烧器燃烧的助燃焦炉煤气提供。
余热回收工序：
从焚烧炉32出来的高温SO 2工艺气进入废热锅炉31，对SO 2工艺气中的高温余热进行回收利用，产生4.0MPaG的饱和蒸汽，产生的蒸汽部分用于冷空气预热器加热焚烧炉内燃烧用的富氧空气，其余部分经减压至0.7MPaG后送至低压蒸汽管网使用，来自管网的除盐水经加药及脱氧处理后送入废热锅炉，将从废热锅炉出来的SO 2工艺气的温度降至350℃后进行净化工序。
净化工序：
来自废热锅炉31的SO 2工艺气依次通过增湿塔29(一级动力波)、冷却塔28(填料塔)、洗净塔27(二级动力波)及电除雾器A26，进行增湿降温、冷却脱水、洗涤净化及硫酸雾脱除，保证进入后续工序的SO 2工艺气中的杂质及水分含量达到工艺要求指标，以防止SO 2转化工艺用催化剂中毒，并保持制酸工艺水平衡。将离开净化工序的SO 2工艺气的温度降至48℃，SO 2工艺气经冷却塔28及洗净塔27冷却降温所放出的热量由塔外冷却器通过冷却水转移。
SO 2工艺气中含有的少量SO 3在净化过程中与水结合生成浓度约2.1％的稀硫酸，最终从增湿塔29排出，经稀酸脱气塔A30脱除SO 2和冷却后，送至煤气净化装置硫铵单元的饱和器使用，无废液外排。
干燥工序：
从净化工序电除雾器A26出来的SO 2工艺气进入干燥25塔，用质量浓度为94％的浓H 2SO 4进行干燥脱水，干燥塔25出口SO 2工艺气的含水量降至0.1g/Nm 3，以满足转化工序干接触法制酸催化剂对工艺气中水分含量的要求。从干燥塔25连续送出94％的干燥酸进入第一吸收塔17循环槽；从第一吸收塔17循环槽向干燥塔25循环槽连续送入质量浓度98％的吸收酸。通过干燥塔25循环槽与第一吸收塔17循环槽的串酸操作，维持干燥塔25内干燥酸的所需浓度。干燥塔25内硫酸吸收水分放出的热量由干燥塔25外冷却器通过冷却水转移。
转化工序：
转化工序采用“3+1”4段催化剂床、二次转化，及“III、I-IV、II”换热工艺流程。
从干燥塔25出来的SO 2工艺气，SO 2浓度为10％，经SO 2风机35加压后，依次通过第III、第I换热器(22、21)，分别与从SO 2转化器III段及I段催化剂床出来的高温转化气换热至约425℃后，进入SO 2转化器I段催化剂床，在催化剂作用下，工艺气中的SO 2与O 2反应，被催化氧化为SO 3。从I段催化剂床出来的高温转化气经热空气加热器和第I换热器21分别依次与来自冷空气余热器的富氧空气和低温SO 2工艺气换热降温后，进入II段催化剂床继续转化，然后经第II换热器19换热降温后，进入III段催化剂床，完成SO 2 一次转化阶段的最后催化氧化过程，最后经第III换热器22，与来自SO 2风机的低温SO 2工艺气换热降温后，送至吸收工序第一吸收塔17。从第一吸收塔17出来的低温SO 2工艺气经第IV、第II换热器(18、19)，分别与从SO 2转化器IV段及II段催化床层出来的高温转化气换热后，进入SO 2转化器IV段催化剂床，进行SO 2的二次转化，然后经第IV换热器换热降温后，送至吸收工序第二吸收塔。SO 2催化转化反应如下：SO 2(g)+1/2O 2(g)→SO 3(g)+100.32kj/mol。
SO 2工艺气两次转化前，即SO 2工艺气进入转化器第I段及第IV段催化剂床前，均设有电加热器20，用于初始开工阶段催化剂加热升温使用。
吸收工序：
来自转化工序的一次转化及二次转化后的工艺气分别进入第一吸收塔17及第二吸收塔16，用98％的浓H 2SO 4对其中的SO 3气体进行吸收，浓硫酸中的H 2O与SO 3反应生成H 2SO 4。SO 3吸收反应如下：SO 3(g)+H 2O(l)→H 2SO 4(l)+134.2kj/mol。
吸收塔内SO 3与水反应放出的热量由外冷却器通过冷却水转移。第一吸收塔17底部生成的98％浓硫酸一部分送至干燥塔25，其余经产品酸冷却器冷却后送入产品酸槽15；来自干燥塔25的94％硫酸送入第一吸收塔17循环槽，通过串酸操作维持第一吸收塔17内吸收酸浓度，第二吸收塔16吸收SO 3产生的98％硫酸进入第一吸收塔17循环槽。各吸收塔循环槽均设有工艺软水补入管线，以调节吸收酸及产品酸浓度。
尾气洗净工序：
尾气洗净工序采用氨法脱硫，从第二吸收塔16排出的制酸尾气进入尾气洗涤塔11，用剩余氨水蒸氨单元产生的原本送生化处理的碱性蒸氨废水喷淋吸收尾气中残余的SO 2和硫酸雾，然后进入电除雾器B13，在高压电场作用下，进一步脱除尾气中夹带的硫酸雾，出电除雾器B13的洁净尾气最后经30m高烟囱14排入大气。从尾气洗涤塔11排出的蒸氨废水送回酚氰废水处理装置处理。
本项目于2017年12月25日顺利投产，业主检测出的主要技术指标和主要环保指标如下：
①主要技术指标
■SO 2最终转化率：＞99.9％。
■硫酸质量
浓度(w％)：98％±0.5％；94％±0.5％(冬季)；颜色澄清透明，各项指标可以达到GB/T534-2014《工业硫酸》中一级品标准。
②主要环保指标
制酸尾气：约7000Nm 3/h，单位产品基准排气量1950Nm/t；其中有害物含量：SO 2含 量：95mg/Nm 3；硫酸雾：检测不到；NO X：125mg/Nm 3；说明：《硫酸工业污染物排放标准》GB26132-2010中规定的外排制酸尾气中有害物排放限值：
一般地区：SO 2＜400mg/Nm 3；硫酸雾＜30mg/Nm 3；NOx含量无指标要求。
生态环境脆弱地区：SO 2＜200mg/Nm 3；硫酸雾＜5mg/Nm 3；NOx含量无指标要求。
实施例2：
以南京某公司燃料供应厂煤气深度脱硫处理项目为例：煤气净化装置脱硫单元的焦炉煤气处理量为88000Nm 3/h，脱硫前焦炉煤气中的H 2S含量为8-10g/Nm 3，脱硫后焦炉煤气中H 2S含量为0.02g/Nm 3，脱硫液中副盐的含量为250g/L，催化剂为HPF。本工程采用“富氧燃烧、二转二吸”制酸技术处理焦炉煤气HPF脱硫产低纯硫磺及副盐废液的工艺，设计硫酸(按100％硫酸计)产量为65.5t/d，其工艺流程中，除了原料预处理工序的硫浆组成和焚烧工序的富氧浓度不同外，其余都与实施例1低品质硫膏和脱硫液副盐资源化利用工程的工艺流程相同。
原料预处理制得的硫浆组成，见表3。
表3 实施例2的硫浆组成
悬浮单质硫 w％ 11.5-16％
NH 4SCN w％ 6.8-13.3％
(NH 4) 2S 2O 3 w％ 3.9-6.67％
(NH 4) 2SO 4 w％ 1.6-1.9％
(NH 4) 2S 6 w％ 0.36-3.4％
(NH 4) 2CO 3 w％ 0.84-1.93％
NH 3 w％ 0.14-0.15％
H 2O w％ 63.7-68％
焚烧工序的富氧空气中氧气浓度为38.5％。
工业实用性
本公开提供的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺及装置能够在工业上批量使用，彻底解决了焦炉煤气氨法湿式氧化脱硫工艺产生的低纯硫磺回收利用及脱硫副盐废液无害化处理等问题，具体地，采用富氧燃烧技术有效降低工艺气量和提高工艺气中SO 2浓度，节省建设投资及运行成本并保证了二转二吸技术的自热平衡，此外，采用二转二吸技术，将SO 2转化率从97.5％提高到99.9％以上，显著提高了硫的回收率，其生产的硫酸可用做焦炉煤气脱氨生产硫酸铵的原料，且大幅降低了吸收工序后尾气中SO 2含量，这实现了硫资源的循环利用以及提高环境保护水平的双重目标。

Claims (20)

  1. 处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其工艺流程包括原料预处理工序、焚烧工序、余热回收工序、净化工序、干燥工序、转化工序、吸收工序、尾气洗净工序，其中焚烧工序采用富氧空气燃烧，转化工序和吸收工序则采用二次转化、二次吸收。
  2. 根据权利要求1所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述原料预处理工序采用沉降离心分离及浓缩技术对煤气脱硫工艺产生的硫泡沫液进行处理。
  3. 根据权利要求1或2所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述原料预处理工序的工艺过程包括：将来自脱硫单元硫泡沫槽的硫泡沫液送入卧式离心机，经固、液两相离心分离后，滤液进入滤液槽，然后用滤液泵抽出，一部分送往浓缩塔，其余送回脱硫单元的脱硫塔；从离心机分出的硫膏进入浆液槽，与来自浓缩塔的脱硫副盐浓缩液强制混合均匀，制得原料硫浆，送至浆液贮槽，然后再由浆液移送泵送往焚烧炉；浓缩塔排出的蒸汽进入凝缩塔冷凝，凝缩液送回脱硫单元的脱硫塔使用；凝缩塔排出的不凝性气体进入煤气净化装置的负压煤气管道。
  4. 根据权利要求1至3中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述原料预处理工序全部在密闭设备及管道内完成。
  5. 根据权利要求1至4中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述焚烧工序的工艺过程包括：将由原料预处理工序送入焚烧炉的原料硫浆，经废液喷枪用工艺压缩空气雾化后，在1050-1250℃温度下，通过分段控制富氧焚烧技术，将原料硫浆中的悬浮单质硫和脱硫副盐中的硫元素转化为SO 2。
  6. 根据权利要求5所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，通过两段控制富氧焚烧技术。
  7. 根据权利要求1至6中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述富氧空气中氧气浓度为25％-45％。
  8. 根据权利要求1至7中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述富氧空气由直接供给的纯氧和燃烧用空气混合制得或者采用分子筛变压吸附工艺制得。
  9. 根据权利要求1至8中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，将净化工序产生的质量浓度为0.5％-5％的稀硫酸送至硫铵单元回收利用，无废液外排。
  10. 根据权利要求1至9中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述转化工序采用“3+1”4段催化剂床、二次转化，及“III、I-IV、II”换热工艺流程，转化塔从上至下依次为I段-IV段催化剂床。
  11. 根据权利要求10所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，“3+1”4段催化剂床、二次转化为干接触法。
  12. 根据权利要求10或11所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，SO 2工艺气进入转化器第I段及第IV段催化剂床前，在初始开工阶段对催化剂进行加热升温。
  13. 根据权利要求1至12中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，所述吸收工序的工艺过程包括：来自转化工序的一次转化及二次转化后的工艺气分别进入第一吸收塔及第二吸收塔。
  14. 根据权利要求1至13中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，尾气洗净工序采用碱法脱硫，其包括：从吸收工序排出的制酸尾气进入尾气洗涤塔，采用碱液喷淋吸收尾气中残余的SO 2和硫酸雾，尾气洗涤塔内多余的吸收液送至生化单元进行处理。
  15. 根据权利要求1至14中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺，其中，尾气洗净工序采用氨法脱硫，其包括：从吸收工序排出的制酸尾气进入尾气洗涤塔，采用氨水喷淋吸收尾气中残余的SO 2和硫酸雾；
    将尾气洗涤塔排出的尾气送入氨吸收塔，以进一步吸收尾气中逃逸的氨；
    将氨吸收塔内生成的硫酸铵溶液送至尾气洗涤塔；以及
    将尾气洗涤塔内多余的亚硫酸铵-硫酸铵溶液送至原料预处理工序随同滤液一起进行浓缩，制成硫浆，或者利用空气氧化成硫酸铵溶液，再送至硫铵单元制取硫酸铵，无废液外排。
  16. 一种如权利要求1至15中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，其包括原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元、尾气洗净单元，所述原料预处理单元、焚烧单元、余热回收单元、净化单元、干燥单元、转化单元、吸收单元和尾气洗净单元按照工艺流程依次设置，其中原料预处理单元的预处理浆液输出管路连接焚烧单元的焚烧炉，焚烧炉的出口管路连接余热回收单元的废热锅炉，废热锅炉的烟气出口管路连接净化单元的增湿塔的烟气入口，净化单元的电除雾器A的出口管路连接干燥单元的干燥塔，转化工序中转化塔的转化器III段催化剂床出口管路连接吸收工序的第一吸收塔，第一吸收塔的烟气出口管路连接转化塔的转化器IV段催化剂床入口，转化塔的转化器 IV段催化剂床出口管路连接吸收工序的第二吸收塔，第二吸收塔的出口管路连接尾气洗净单元的尾气洗涤塔，第一吸收塔底部的硫酸出口管路连接干燥单元的干燥塔。
  17. 根据权利要求16所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，其中，所述原料预处理单元包括泡沫槽、滤液槽、浆液槽、离心机、浆液贮槽，泡沫槽的出口管路通过泵连接离心机的入口，离心机的滤液出口连接滤液槽，离心机的硫膏出口连接浆液槽，浆液槽的出口连接浆液贮槽，在所述浆液槽和浆液贮槽中均设有机械搅拌器。
  18. 根据权利要求16或17所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，其中，所述尾气洗净单元包括尾气洗涤塔、电除雾器B、烟囱，尾气洗涤塔的烟气出口连接电除雾器B，电除雾器B的烟气出口连接烟囱。
  19. 根据权利要求15至18中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，其中，所述尾气洗净单元包括尾气洗涤塔、氨吸收塔、电除雾器B、烟囱，尾气洗涤塔的烟气出口连接氨吸收塔，氨吸收塔的烟气出口连接电除雾器B，电除雾器B的烟气出口连接烟囱，氨吸收塔的硫酸铵溶液出口连接尾气洗涤塔，尾气洗涤塔的亚硫酸铵-硫酸铵溶液出口连接原料预处理单元的浓缩塔。
  20. 根据权利要求15至19中任一项所述的处理焦炉煤气脱硫产低纯硫磺及副盐废液的工艺采用的装置，其中，所述第一吸收塔和第二吸收塔均设有工艺软水补入管线。
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