Novel claus system for recovering sulfur from acid gas

Abstract

Disclosed in the present invention is a novel Claus system for recovering sulfur from acid gas, comprising an acid gas combustion subsystem, a combustion advanced analysis and control subsystem and a conversion subsystem. The acid gas combustion subsystem comprises a sulfur-producing combustion furnace. The combustion advanced analysis and control subsystem is used for monitoring the flow rates of acid gas, process tail gas and air in real time, monitoring the concentration parameters of components in the acid gas and the process tail gas as well as the temperature parameter of a burner of the sulfur-producing combustion furnace, controlling the flow rate of air entering the burner, and controlling the proportions of the acid gas entering the burner, a hearth of the sulfur-producing combustion furnace as well as the conversion subsystem, so as to control the temperature of the burner of the combustion furnace to be within a preset range, and control the proportion of H2S and SO2 in the gas entering the conversion subsystem to reach a preset value 2:1. The conversion subsystem is used for carrying out a low-temperature catalytic reaction on high-temperature process gas discharged from the sulfur-producing combustion furnace, so as to generate elemental sulfur. By means of the technical optimization of the Claus process itself, the present invention improves the sulfur recovery rate, and further matching with a reasonable tail gas treatment process will reduce the costs and production energy consumption of sulfur recovery devices to a certain extent, thus improving the yield of sulfur.

Description

A new Claus system for acid gas sulfur recovery Technical Field

[0001] The present invention belongs to the field of coal chemical industry, and particularly relates to a novel Claus process system for treating acid gas containing hydrogen sulfide and producing sulfur as a by-product. Background Art

[0002] Coal chemical industry uses coal as a raw material, converting it into gaseous, liquid, and solid products or semi-products through chemical processing, which are then further processed into chemical and energy products. Raw coal contains sulfur, much of which is converted into sulfur-containing components such as H2S during processing and exists in gaseous form. These H2S-containing gases are collectively referred to as acid gas. To protect the environment, H2S-containing acid gas is recovered as by-products such as sulfur and sulfuric acid. The Claus process is the most commonly used sulfur recovery unit, and most sulfur recovery processes are developed based on the Claus process. The Claus process consists of a high-temperature sulfur production reaction in a sulfur production furnace and a low-temperature catalytic reaction in various stages of the converter. In the Claus process, acid gas is oxidized by air (or oxygen-enriched air) in the sulfur production furnace to SO2, which then undergoes a high-temperature Claus reaction to produce elemental sulfur. The process gas then undergoes a low-temperature catalytic reaction in various stages of the converter, loaded with catalysts, to produce elemental sulfur.

[0003] The two-stage and three-stage Claus processes, collectively referred to as the conventional Claus process, are widely used in sulfur recovery plants. The difference lies in the number of converter stages. A process with a two-stage converter for low-temperature catalysis is called a two-stage Claus process. Sulfur recovery rate is a key metric for sulfur recovery plants. The theoretical sulfur recovery rate for a two-stage Claus process is 90-95%, while that for a three-stage Claus process is 95-98%. Due to factors such as reaction thermodynamic equilibrium and acid gas H2S concentration, sulfur recovery rates in sulfur production plants using the conventional Claus process are lower than the theoretical value. For example, the actual recovery rate of the two-stage Claus process in coal chemical plants is 85-93%. Because some sulfur is not recovered in the conventional Claus process, the sulfur production tail gas cannot be discharged directly and must undergo further desulfurization treatment in an exhaust gas treatment system before it meets emission standards.

[0004] The conventional Claus process has seen significant development, primarily in two areas: first, improvements to the Claus process itself to increase sulfur recovery rates, including the development of new catalysts, lean acid gas sulfur production technologies, and oxygen-based sulfur recovery processes; and second, the development of suitable tail gas treatment processes. Optimization of both sulfur recovery and tail gas treatment processes is ultimately aimed at maximizing sulfur recovery rates.

[0005] Summary of the Invention

[0006] The present invention addresses the shortcomings of conventional Claus processes in coal chemical plants, such as low concentrations of acid gas byproducts, which fluctuate significantly due to coal quality. These shortcomings are compounded by the low sulfur recovery rate, large fluctuations in operating parameters, and high tail gas treatment costs associated with conventional Claus processes. To address these shortcomings, and considering that direct discharge of distillation tail gas, nitrogen-washed tail gas, and other process tail gases with a certain calorific value from coal chemical plants does not meet environmental regulations, the present invention provides a novel Claus sulfur recovery system and method. These systems offer stable and reliable operation, high sulfur recovery rates, coordinated treatment of process tail gases, and low product energy consumption. These systems are suitable for treating acid gas and process tail gases from various coal chemical plants, and for producing sulfur products as byproducts.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions: a novel Claus system for acid gas sulfur recovery, comprising: an acid gas combustion subsystem, a combustion advanced analysis and control subsystem, and a conversion subsystem;

[0008] The acid gas combustion subsystem includes a sulfur-making combustion furnace, which includes a furnace and a burner;

[0009] The advanced combustion analysis and control subsystem is used to monitor the flow rates of acid gas, process exhaust gas, and air in real time, monitor the concentration parameters of components in the acid gas and the temperature parameters of the sulfur production burner, control the air flow entering the burner, and control the ratio of acid gas entering the sulfur production burner burner, furnace, and conversion subsystem, thereby controlling the burner temperature of the burner within a preset range and controlling the ratio of H2S to SO2 in the gas entering the conversion subsystem to a preset value of 2:1;

[0010] The advanced combustion analysis and control subsystem controls the acid gas to enter the burner of the sulfur-making combustion furnace for combustion with hot air, or controls the acid gas to be divided into three parts, one part enters the burner of the sulfur-making combustion furnace for combustion with hot air, the second part enters the furnace of the sulfur-making combustion furnace for high-temperature Claus reaction, and the third part is mixed with the high-temperature process gas from the sulfur-making combustion furnace and then enters the conversion subsystem; the advanced combustion analysis and control subsystem controls the process exhaust gas to enter the burner of the sulfur-making combustion furnace for combustion with hot air;

[0011] The conversion subsystem is used to convert the high-temperature process gas from the sulfur-producing combustion furnace into elemental sulfur through a low-temperature catalytic reaction.

[0012] Furthermore, the advanced combustion analysis and control subsystem controls the acid gas entering the burner of the sulfur-making combustion furnace to account for 40% to 100% of the total flow, the acid gas entering the sulfur-making combustion furnace to account for 0% to 60% of the total flow, and the acid gas entering the post-conversion subsystem of the sulfur-making combustion furnace to account for 0% to 20% of the total flow.

[0013] Furthermore, the combustion advanced analysis and control subsystem includes flow and temperature measuring instruments, component online analyzers, comprehensive combustion analysis systems, and complex control systems;

[0014] The flow and temperature measuring instrument is used to detect the flow and temperature of acid gas, process tail gas, air and sulfur production tail gas discharged from the system;

[0015] The component online analyzer is arranged on the acid gas pipeline and the process tail gas pipeline to detect the concentration of combustible components in the gas, and is arranged on the sulfur production tail gas pipeline to detect the concentration of sulfur-containing components in the gas;

[0016] The comprehensive combustion analysis system is used to calculate the total amount of air required based on the acid gas flow rate and H2S / SO2 content, process tail gas flow rate and composition, and adaptively control the actual air flow entering the burner according to the H2S / SO2 content in the sulfur production tail gas;

[0017] The complex control system is used to control the temperature of the burner of the sulfur-making combustion furnace within a preset range by controlling the ratio of acid gas entering the burner and furnace, and to control the air flow rate and the diversion flow rate of the acid gas so that the ratio of H2S and SO2 in the gas entering the conversion subsystem is 2:1.

[0018] Furthermore, acid gas is gas containing H2S, and process tail gas is tail gas with a certain calorific value emitted by an external coal chemical plant.

[0019] Furthermore, the novel Claus system also includes a fire-tube waste heat boiler, which is arranged between the sulfur-producing combustion furnace and the conversion subsystem. The conversion subsystem includes a two-stage or three-stage Claus device. Each stage of the Claus device includes a group of sulfur condensers and a conversion system. The high-temperature process gas exiting the sulfur-producing combustion furnace enters the by-product medium-pressure steam of the directly connected fire-tube waste heat boiler and is cooled. The process gas enters the first-stage sulfur condenser at a tangent position at the bottom of the waste heat boiler outlet pipe box. The process gas is cooled in the first-stage sulfur condenser, and liquid sulfur is condensed and separated from the process gas. The process gas after the liquid sulfur is separated enters the first-stage conversion system. The conversion subsystem is also provided with a final sulfur condenser in the last stage of the Claus device.

[0020] Furthermore, each stage of the Claus unit also includes a heater and a distributor. The process gas from the sulfur outlet condenser is preheated to a certain temperature by the heater and then evenly distributed by the distributor before entering the converter.

[0021] The distributor is in the form of a semicircular tube, the diameter of the semicircular tube is 0.3 to 1.0 times the diameter of the reactor inlet pipe, and the length is 0.3 to 0.8 times the diameter of the converter. Two identical semicircular tubes are connected in parallel, and the connection coincides with the center line of the inlet pipe. Distribution grooves or distribution holes are evenly distributed on the cylindrical surface, and the groove area or hole area is 0.8 to 1.5 times the cross-sectional area of ​​the inlet pipe.

[0022] Furthermore, the new Claus system also includes a high-efficiency sulfur collector, which is connected to the conversion subsystem. The process gas leaving the conversion subsystem enters the high-efficiency sulfur collector. The sulfur collector is equipped with high-efficiency separation internals to further recover liquid sulfur droplets in the process gas.

[0023] Furthermore, the new Claus system also includes an overheating treatment subsystem, which is connected to a high-efficiency sulfur collector to further treat the sulfur-making tail gas leaving the sulfur collector, and then superheat the sulfur-making tail gas to a certain temperature and send it to the boiler system.

[0024] Furthermore, the burner temperature control range of the sulfur-making combustion furnace is 950-1500° C.; the furnace temperature control range of the sulfur-making combustion furnace is 800-1200° C., and the pressure control range is 1.7-2.0 Bara.

[0025] Furthermore, the sulfur recovery rate of the new Claus system is 92% to 98%, and the total volume content of H2S and SO2 in the sulfur production tail gas is controlled within the range of 0.2% to 1.0%.

[0026] The purpose of the present invention can be achieved through the following technical solutions:

[0027] a. The acid gas pipeline is equipped with an online analyzer for H2S and other components, and is preheated to a certain temperature before being sent to the sulfur-making combustion furnace. The preheated acid gas is divided into three parts. The first part enters the sulfur-making combustion furnace burner and burns with hot air. The raw gas flow rate of this part is required to be as large as possible. The second part of the raw gas enters the sulfur-making combustion furnace furnace to undergo a high-temperature Claus reaction. The third part is mixed with the high-temperature process gas leaving the sulfur-making combustion furnace and then enters the conversion subsystem.

[0028] b. The process tail gas pipeline is equipped with an online analyzer for combustible components such as CO, H2, and CH4, and all of them are sent to the burner of the sulfur-making furnace for treatment;

[0029] c. The oxidizing medium for acid gas combustion is air (or oxygen-enriched air), which comes from the blower air (or compressed air or low-pressure oxygen from outside). After being preheated to a certain temperature, the air enters the sulfur production burner, where combustion strictly follows a 2:1 ratio of H2S to SO2. The H2S to SO2 ratio in the sulfur production burner is controlled by adjusting the air / acid gas ratio. The combustion air volume is controlled by the main and auxiliary air regulators. The main air flow accounts for approximately 70-90% of the total air volume, and the fine-tuning air flow accounts for approximately 10-30% of the total air volume. Controlling the H2S / SO2 ratio is the most important operating parameter of the sulfur recovery unit. The sulfur production burner is equipped with a dedicated comprehensive combustion analysis system. This system calculates the correct total air volume based on the raw acid gas flow and component content, the process off-gas flow and component content, and the sulfur production off-gas flow and component content, and achieves precise control through comprehensive control.

[0030] d. In order to improve the sulfur recovery rate of low-concentration acid gas, make full use of process tail gas with a certain calorific value discharged from coal chemical production equipment such as distillation tail gas and nitrogen washing tail gas for co-combustion to increase the temperature, which can improve the sulfur recovery rate of the Claus unit and coordinately deal with the pollution problem of direct discharge of process tail gas into the atmosphere.

[0031] e. The high-temperature process gas from the sulfur production combustion furnace enters the medium-pressure steam produced as a by-product of the directly connected fire-tube waste heat boiler and is cooled. The process gas enters the primary sulfur condenser at the tangent position at the bottom of the waste heat boiler outlet pipe box. The process gas pipeline is gradually lowered and has a certain slope. The process gas is then further cooled in the primary sulfur condenser, and liquid sulfur is condensed and separated from the process gas. The process gas after separation of liquid sulfur enters the primary conversion system.

[0032] f. The process gas exiting the primary sulfur condenser is preheated to a certain temperature by the primary heater and evenly distributed through a distributor before entering the primary converter. The catalyst in the primary converter is mixed, with a certain amount of oxygen-protected Claus catalyst in the upper layer and a certain amount of organic sulfur hydrolysis catalyst in the lower layer. The process gas exiting the primary converter first enters the primary heater to preheat the inlet process gas, then enters the secondary sulfur condenser for further cooling. Liquid sulfur is condensed and separated from the process gas, and the process gas after liquid sulfur separation enters the secondary conversion system.

[0033] g. The process gas exiting the secondary sulfur condenser is heated to a certain temperature by a secondary heater and evenly distributed by a distributor before entering the secondary converter, which is loaded with a high-efficiency Claus catalyst. The process gas exiting the secondary converter enters the tertiary sulfur condenser for cooling, where liquid sulfur is condensed and separated from the process gas. After separation of the liquid sulfur, the process gas enters a high-efficiency sulfur collector (or a three-stage conversion system using a three-stage Claus process, with the same process flow as the secondary conversion system).

[0034] To achieve a high sulfur recovery rate, the process gas outlet temperature at the final sulfur condenser is lowered, producing low-pressure steam as a byproduct. This steam is cooled in an air cooler and then recycled as boiler water. The process gas exiting the final sulfur condenser enters a high-efficiency sulfur collector. The sulfur collector is equipped with high-efficiency separation internals to further recover liquid sulfur droplets from the process gas.

[0035] i. Liquid sulfur separated from each sulfur condenser is sealed and then flows by gravity into the liquid sulfur pool. Hot air is used to degas the liquid sulfur. The tail gas from the liquid sulfur pool is extracted and pressurized by a steam ejector before being sent to the sulfur production combustion furnace for further processing and recovery. The tail gas from the sulfur trap requires further treatment. To reduce the investment and cost of tail gas treatment, the coal chemical plant's boiler system is used to co-process the tail gas. To avoid problems such as liquid sulfur solidification, the tail gas is superheated to a certain temperature before being sent to the boiler system.

[0036] The raw gas described in the present invention is H2S-rich acid gas produced as a by-product of the desulfurization system of a coal chemical plant, wherein the H2S molar content is 20% to 50%, the (N2+CO2) molar content is 30% to 70%, the methanol content is 0.1 to 1%, the acid gas temperature is 20 to 40°C, and the acid gas pressure is 1.8 to 3.0 Bara.

[0037] The process tail gas is the tail gas with a certain calorific value discharged from the coal chemical plant, in which the molar content of H2S is 1% to 5%, the content of combustible components such as hydrocarbons, CH4, CO, H2, etc. is 1 to 40%, and the rest are inert components such as N2 and AR. The tail gas temperature is 20 to 100°C and the tail gas pressure is 2 to 10 Bara.

[0038] The acid gas entering the sulfur recovery system is preheated to 150-220°C and then divided into three parts. The first part enters the burner of the sulfur-making combustion furnace for combustion with hot air, with a flow rate ratio of 40-100%; the second part enters the furnace of the sulfur-making combustion furnace, with a flow rate ratio of 0-40%; the third part of the acid gas is mixed with the high-temperature process gas leaving the sulfur-making combustion furnace and then enters the conversion subsystem, with a flow rate ratio of 0-20%.

[0039] The sulfur-making combustion furnace is equipped with a high-efficiency low-nitrogen burner to maintain stable combustion of acid gas, with a temperature control range of 950-1500°C; the furnace temperature control range of the sulfur-making combustion furnace is 800-1200°C, and the pressure control range is 1.7-2.0 Bara.

[0040] The sulfur-making combustion furnace is equipped with a directly connected fire tube waste heat boiler to produce medium-pressure steam as a by-product. The steam pressure range is 2.0 to 6.0 MPaG, and the process gas temperature at the outlet of the waste heat boiler is controlled in the range of 260 to 340°C.

[0041] Each level of converter is equipped with a distributor to evenly distribute the airflow. The temperature control range of the process gas entering the first-stage converter is 225-245°C, and the catalyst bed temperature is 260-340°C; the temperature control range of the process gas entering the second-stage converter is 205-230°C, and the bed hotspot temperature is 230-300°C; the temperature control range of the process gas entering the third-stage converter is 195-220°C, and the bed hotspot temperature is 210-240°C.

[0042] The sulfur recovery rate of the new Claus process is about 92-98%, the (H2S+SO2) content of the sulfur-making tail gas is controlled in the range of 0.2-1.0%, and the heating temperature of the sulfur-making tail gas is controlled in the range of 160-240°C.

[0043] The sulfur production tail gas treatment process adopts boiler system collaborative treatment.

[0044] The process gas is cooled and liquid sulfur is separated through sulfur condensers at various levels. The outlet temperature is controlled in the range of 150-200°C, and the pressure of by-product steam of sulfur condensers at various levels is controlled in the range of 0.4-0.8MPaG.

[0045] The process gas is cooled by the final sulfur condenser, and the outlet temperature is controlled within the range of 125-140°C. The pressure of the by-product steam of the third-stage sulfur condenser is controlled within the range of 0.1-0.2 MPaG. This level of steam is cooled into condensate by an air cooler and recycled as boiler water.

[0046] The tail gas from the liquid sulfur pool is extracted and pressurized by a steam ejector and then sent to the furnace of the sulfur-making combustion furnace for recovery and treatment. The furnace of the sulfur-making combustion furnace is provided with a specially structured pipe opening for treating the tail gas.

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] (1) The sulfur-making combustion furnace can achieve a higher combustion temperature through technical measures such as acid gas / air preheating and co-firing of process tail gas, which can maintain stable combustion and obtain a higher sulfur recovery rate.

[0049] (2) Properly increasing the operating pressure of the sulfur-making furnace is beneficial to the high-temperature Claus reaction and can improve the yield.

[0050] (3) The sulfur-making combustion furnace is equipped with a direct-connected fire tube waste heat boiler to produce medium-pressure steam as a by-product. The outlet temperature is high and there is no liquid sulfur condensation. Therefore, the temperature difference of the waste heat boiler is low, and the service life of the waste heat boiler is long. The process gas outlet of the waste heat boiler is set at the bottom tangent position of the outlet pipe box, and slopes to the inlet of the first-stage sulfur condenser through a step-by-step low pipeline, without liquid sulfur accumulation.

[0051] (4) A new type of gas distributor is installed at each level of converter, so that the process gas is evenly distributed, the catalyst bed has basically no bias flow, and the reaction efficiency is high.

[0052] (5) The secondary converter and the tertiary converter (if any) are all loaded with high-efficiency and low-temperature Claus catalysts, which can increase the driving force of the Claus reaction and improve the sulfur recovery rate.

[0053] (6) The sulfur-making combustion furnace is equipped with a comprehensive analysis system for combustion air distribution, which accurately calculates the air distribution volume and strictly controls the exhaust gas H2S / SO2 ratio to 2:1, thereby improving the sulfur recovery rate of each level of converter.

[0054] (7) The high-efficiency sulfur collector uses high-efficiency separation internals, which has high liquid sulfur separation efficiency and less liquid sulfur droplets escape.

[0055] (8) The sulfur production tail gas is heated and sent to the boiler system for coordinated treatment, eliminating the tail gas incinerator, saving combustion gas consumption, and reducing the operating cost of the sulfur recovery device.

[0056] (9) The tail gas from the liquid sulfur pool is pressurized and sent to the furnace of the sulfur-making combustion furnace for treatment, which can avoid the environmental problems of direct emissions and improve the total sulfur recovery rate.

[0057] (10) The hot air used for degassing the liquid sulfur pool comes from the air cooler of the final sulfur condenser, which fully utilizes the heat of low-grade steam and reduces the energy consumption of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG1 is a schematic structural diagram of a novel Claus system for acid gas sulfur recovery according to an embodiment.

[0059] Figure numerals: 101 - online acid gas component analyzer; 102 - acid gas heater; 103 - blower; 104 - integrated sulfur production / combustion analysis system; 105 - air heater; 106 - sulfur production combustion furnace burner; 107 - sulfur production combustion furnace; 108 - waste heat boiler; 109 - primary sulfur condenser; 110 - primary heater; 111 - primary converter; 112 - secondary sulfur condenser; 113 - secondary heater; 114 - secondary converter; 115 - tertiary sulfur condenser; 116 - high-efficiency sulfur collector; 117 - tail gas heater; 118 - boiler system; 119 - air cooler; 120-123 - liquid sulfur seal; 124 - liquid sulfur pool; 125 - liquid sulfur pump; 126 - steam ejector; 127 - online sulfur production tail gas component analyzer; 128 - online analyzer of combustible components in process tail gas.

[0060] FIG2 is a schematic structural diagram of a distributor according to an embodiment. DETAILED DESCRIPTION

[0061] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0062] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0063] For example, consider the acid gas produced as a byproduct of low-temperature methanol scrubbing and the process off-gas produced as a byproduct of liquid nitrogen scrubbing in a coal chemical plant. The acid gas temperature is 35°C, the pressure is 2 barA, and the molar flow rate is 100 kmol / h. The molar composition is shown in Table 1 below.

[0064] Table 1

[0065] The process tail gas temperature is 30°C, the pressure is 3.5 BarA, and the molar flow rate is 10 kmol / h. The molar composition is shown in Table 2 below.

[0066] Table 2

[0067] The acid gas has a molar content of 31.2748% H2S + COS, making it a low-concentration acid gas. An online component analyzer 101 is installed on the acid gas pipeline entering the sulfur recovery unit, enabling real-time analysis of the contents of combustible components such as H2S + COS, H2, and CH3OH in the acid gas. A component analyzer 128 is also installed on the process off-gas pipeline, enabling real-time analysis of the contents of combustible components such as CO, H2, and CH4 in the acid gas. This analysis data, along with the acid gas and process off-gas flow rates, is analyzed and calculated by the sulfur production / combustion comprehensive analysis system 104 to determine the theoretical air supply volume. Afterwards, all the process exhaust gas enters the sulfur production furnace burner 106. The acid gas is preheated to 210°C by heater 102 and then divided into three parts. The first part, approximately 70% of the total gas volume, enters the sulfur production furnace burner 106 and is combusted with a certain proportion of hot air. The second part, approximately 20% of the total gas volume, enters the sulfur production furnace hearth 107 to undergo a high-temperature Claus reaction. The furnace temperature is approximately 890°C. The hot air used for combustion is compressed air from outside or introduced by a blower. The air flow requirement is approximately 74 kmol / h, calculated by the sulfur production / combustion comprehensive analysis system 104. The hot air is heated to 210°C by heater 105 and enters the sulfur production furnace burner 106 via the main pipeline (80% of the gas volume, main regulation) and branch pipeline (20% of the gas volume, auxiliary regulation). The sulfur production exhaust gas pipeline at the device outlet is equipped with an online component analyzer. The analysis data is analyzed and calculated by the sulfur production / combustion comprehensive analysis system 104, and adaptive feedback is used to adjust the air flow in the branch pipeline. The high-temperature process gas from the sulfur-making combustion furnace 106 first enters the waste heat boiler 108 to produce 4.0 MPaG steam, and the temperature is reduced to 320°C.

[0068] The process gas then enters the primary sulfur condenser 109, producing 0.6 MPaG steam as a by-product. The temperature is reduced to 180°C, while liquid sulfur is condensed and separated from the process gas. The process gas is then mixed with the remaining acid gas from the third portion and heated to 240°C in the primary heater 110 before entering the primary reformer 111, where the Claus reaction and organic sulfur hydrolysis reactions occur under the catalytic action of a mixed catalyst. The process gas is then first heated in the primary heater 110, where it is then sent to the secondary sulfur condenser 112, producing 0.6 MPaG steam as a by-product. The temperature is then reduced to 170°C, while liquid sulfur is condensed and separated from the process gas. The process gas is then heated to 210°C in the secondary heater 113 before entering the secondary reformer 114, where the Claus sulfur production reaction occurs under the catalytic action of a high-efficiency catalyst. The process gas then enters the tertiary sulfur condenser 115, producing 0.1 MPaG steam as a by-product. This steam is condensed in an air cooler 119 and recycled as boiler water, reducing the process gas temperature to 130°C. Liquid sulfur is simultaneously condensed and separated from the process gas. The process gas then enters the high-efficiency sulfur collector 116 to recover residual liquid sulfur droplets. The gas from which the liquid sulfur droplets have been separated becomes sulfur production tail gas. This tail gas is heated to 200°C in the tail gas heater 117 and sent to the boiler system 118 for coordinated treatment and discharge to standard levels.

[0069] Liquid sulfur recovered from each stage of the sulfur condenser and high-efficiency sulfur collector passes through liquid sulfur seals 120-123 and enters the liquid sulfur pool. Hot air from the outlet of air cooler 119 is used as the degassing medium for the liquid sulfur. The tail gas from the liquid sulfur pool is pressurized to 2 barA by steam ejector 126 and sent to the sulfur production furnace 107 for combustion.

[0070] The temperature of the sulfur-producing tail gas is 200° C., the pressure is 1.2 BarA, the molar flow rate is 157 kmol / h, the (H2S+SO2) content is 0.771%, and the sulfur recovery rate is 95.2%.

[0071] The system and method of the present invention can improve the sulfur recovery rate by about 2% compared with the conventional two-stage Claus process, has obvious beneficial effects, and can be used to produce recovered sulfur.

[0072] The above embodiment is used to produce sulfur. It only needs to be slightly modified on the basis of this embodiment, and a three-stage converter is added. Then it can be used to replace the conventional three-stage Claus process for producing sulfur.

[0073] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions that do not depart from the concept of the present invention are within the scope of protection of the present invention.

Claims

1. A new Claus system for acid gas sulfur recovery, characterized by include: Acid gas combustion subsystem, combustion advanced analysis and control subsystem, and conversion subsystem; The acid gas combustion subsystem includes a sulfur-making combustion furnace, which includes a furnace and a burner; The advanced combustion analysis and control subsystem is used to monitor the flow rates of acid gas, process exhaust gas, and air in real time, monitor the concentration parameters of components in the acid gas and the temperature parameters of the sulfur production burner, control the air flow entering the burner, and control the ratio of acid gas entering the sulfur production burner burner, furnace, and conversion subsystem, thereby controlling the burner temperature of the burner within a preset range and controlling the ratio of H2S to SO2 in the gas entering the conversion subsystem to a preset value of 2:1; The advanced combustion analysis and control subsystem controls the acid gas to enter the burner of the sulfur-making combustion furnace for combustion with hot air, or controls the acid gas to be divided into three parts, one part enters the burner of the sulfur-making combustion furnace for combustion with hot air, the second part enters the furnace of the sulfur-making combustion furnace for high-temperature Claus reaction, and the third part is mixed with the high-temperature process gas from the sulfur-making combustion furnace and then enters the conversion subsystem; The combustion advanced analysis and control subsystem controls the process tail gas to enter the burner of the sulfur-making combustion furnace and be burned with hot air; The conversion subsystem is used to convert the high-temperature process gas from the sulfur-producing combustion furnace into elemental sulfur through a low-temperature catalytic reaction.

2. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The advanced combustion analysis and control subsystem controls the acid gas entering the burner of the sulfur-making combustion furnace to account for 40% to 100% of the total flow, the acid gas entering the sulfur-making combustion furnace to account for 0% to 60% of the total flow, and the acid gas entering the post-conversion subsystem of the sulfur-making combustion furnace to account for 0% to 20% of the total flow.

3. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The combustion advanced analysis and control subsystem includes a flow and temperature measuring instrument, a component online analyzer, a comprehensive combustion analysis system and a complex control system; The flow and temperature measuring instrument is used to detect the flow and temperature of acid gas, process tail gas, air and sulfur production tail gas discharged from the system; The component online analyzer is arranged on the acid gas pipeline and the process tail gas pipeline to detect the concentration of combustible components in the gas, and is arranged on the sulfur production tail gas pipeline to detect the concentration of sulfur-containing components in the gas; The comprehensive combustion analysis system is used to calculate the total amount of air required based on the acid gas flow rate and H2S / SO2 content, process tail gas flow rate and composition, and adaptively control the actual air flow entering the burner according to the H2S / SO2 content in the sulfur production tail gas; The complex control system is used to control the temperature of the burner of the sulfur-making combustion furnace within a preset range by controlling the ratio of acid gas entering the burner and furnace, and to control the air flow rate and the diversion flow rate of the acid gas so that the ratio of H2S and SO2 in the gas entering the conversion subsystem is 2:

1.

4. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The acid gas is a gas containing H2S, and the process tail gas is a tail gas with a certain calorific value discharged from an external coal chemical plant.

5. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The novel Claus system also includes a fire-tube waste heat boiler, which is arranged between the sulfur-producing combustion furnace and the conversion subsystem. The conversion subsystem includes a two-stage or three-stage Claus unit. Each Claus unit includes a set of sulfur condensers and a conversion system. The high-temperature process gas exiting the sulfur-producing combustion furnace enters the by-product medium-pressure steam of the directly connected fire-tube waste heat boiler and is cooled. The process gas enters the first-stage sulfur condenser at a tangent position at the bottom of the waste heat boiler outlet pipe box. The process gas is cooled in the first-stage sulfur condenser, and liquid sulfur is condensed and separated from the process gas. The process gas after the liquid sulfur is separated enters the first-stage conversion system. The conversion subsystem is also provided with a final sulfur condenser at the last-stage Claus unit.

6. The novel Claus system for acid gas sulfur recovery according to claim 5, characterized in that: Each stage of the Claus device further includes a heater and a distributor. The process gas from the sulfur outlet condenser is preheated to a certain temperature by the heater and then evenly distributed by the distributor before entering the converter. The distributor is in the form of a semicircular tube, the diameter of the semicircular tube is 0.3 to 1.0 times the diameter of the reactor inlet pipe, and the length is 0.3 to 0.8 times the diameter of the converter. Two identical semicircular tubes are connected in parallel, and the connection coincides with the center line of the inlet pipe. Distribution grooves or distribution holes are evenly distributed on the cylindrical surface, and the groove area or hole area is 0.8 to 1.5 times the cross-sectional area of the inlet pipe.

7. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The novel Claus system further comprises a high-efficiency sulfur collector, which is connected to the conversion subsystem. The process gas exiting the conversion subsystem enters the high-efficiency sulfur collector. The sulfur collector is provided with high-efficiency separation internals to further recover liquid sulfur droplets in the process gas.

8. The novel Claus system for acid gas sulfur recovery according to claim 7, characterized in that: The novel Claus system further includes an overheating treatment subsystem, which is connected to a high-efficiency sulfur trap to further treat the sulfur-producing tail gas leaving the sulfur trap, and then superheat the sulfur-producing tail gas to a certain temperature before sending it to the boiler system.

9. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The burner temperature control range of the sulfur-making combustion furnace is 950-1500° C.; the furnace temperature control range of the sulfur-making combustion furnace is 800-1200° C., and the pressure control range is 1.7-2.0 Bara.

10. The novel Claus system for acid gas sulfur recovery according to claim 1, characterized in that: The sulfur recovery rate of the novel Claus system is 92% to 98%, and the total volume content of H2S and SO2 in the sulfur-producing tail gas is controlled within a range of 0.2% to 1.0%.

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