System and method for recovering sulfur in crude hydrogen sulfide gas

Abstract

The invention discloses a system and a method for recovering sulfur in crude hydrogen sulfide gas, and relates to the technical field of gas purification and resource recovery. The system comprises a first heat exchanger and a second heat exchanger which are arranged in parallel, each heat exchanger is provided with a shell pass and a tube pass, the shell passes are used for introducing crude hydrogen sulfide gas, and the tube passes can be alternately introduced with circulating water or steam; the first filter and the second filter are connected in parallel and are used for intercepting unrecycled sulfur powder. According to the method, whether sulfur melting operation needs to be carried out or not is judged by monitoring outlet temperature, pressure difference and liquid level signals, and continuous operation is achieved through alternate operation of the double heat exchangers. The problems that a traditional device is prone to being blocked and needs to be stopped frequently are solved, and efficient recovery of sulfur and continuous operation of equipment are achieved.

Description

Technical Field

[0001] This invention belongs to the field of gas purification and resource recovery technology, specifically relating to a sulfur recovery system and method in crude hydrogen sulfide gas. Background Technology

[0002] Currently, in industry, crude hydrogen sulfide gas is usually prepared by reacting sulfur with hydrogen under the action of a catalyst. However, the crude product often contains unreacted molten sulfur or sulfur vapor. When the gas enters subsequent low-temperature processes such as cooling, separation or distillation (the temperature is about 112.8°C below the freezing point of sulfur), the molten sulfur rapidly condenses and crystallizes, depositing on the inner walls of pipes, valves, heat exchangers and distillation tower plates. The continuous accumulation of sulfur crystals will lead to: (1) blockage of the flow channels, a sharp increase in system pressure drop, forcing the unit to be shut down frequently for cleaning; (2) blockage of distillation tower plates, which will destroy the gas-liquid mass transfer efficiency and seriously affect the purity of the product; (3) local blockage will cause equipment overpressure, resulting in major safety hazards such as leakage and pipe bursts; (4) waste of sulfur resources, increasing raw material consumption and environmental burden.

[0003] Existing technologies often employ methods such as continuous heating or periodic steam purging to alleviate blockages. However, these methods are energy-intensive, complex to operate, and cannot achieve continuous and stable operation, making it difficult to fundamentally solve the problem of sulfur precipitation in low-temperature regions. Therefore, there is an urgent need for a technical solution that can efficiently and continuously intercept and recover sulfur entrained in crude hydrogen sulfide gas without affecting the main process flow. Summary of the Invention

[0004] In view of this, the present invention provides a sulfur recovery system and method in crude hydrogen sulfide gas. Through an integrated system of "alternating condensation and crystallization of dual heat exchangers + precision interception of dual filters", combined with switching logic based on temperature, pressure difference and liquid level, the system achieves efficient, continuous and safe recovery of molten sulfur in crude hydrogen sulfide gas. It solves the technical problem of sulfur clogging pipelines and equipment under low temperature conditions and ensures long-term stable operation of industrial plants.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a sulfur recovery system from crude hydrogen sulfide gas, comprising a first heat exchanger, a second heat exchanger, a first filter, and a second filter; the first and second heat exchangers are connected in parallel, and each heat exchanger includes a shell side and a tube side; the lower middle part of the shell side of the first heat exchanger is provided with a first gas inlet, which is connected to a first inlet pipeline; the upper part of the shell side of the first heat exchanger is provided with a first gas outlet, which is connected to a first gas outlet pipeline, and the first gas outlet pipeline is connected to the inlet of the first filter; the lower middle part of the shell side of the second heat exchanger is provided with a second gas inlet, which is connected to a second inlet pipeline; the upper part of the shell side of the second heat exchanger is provided with a second gas outlet, which is connected to a second gas outlet pipeline, and the second gas outlet pipeline is connected to the inlet of the second filter; the first and second filters are connected in parallel to alternately intercept residual sulfur powder in the gas after treatment by the heat exchangers.

[0006] Preferably, the first heat exchanger includes a first heat exchange tube in the tube side and a first outer coil wound around the outside of the shell side; one end of the first heat exchange tube is connected to a first circulating water inlet pipeline and the other end is connected to a first circulating water outlet pipeline for circulating water to be introduced for cooling; the first heat exchange tube is connected to a first heat exchange tube steam inlet pipeline, and the first heat exchange tube condensate outlet is also connected to a first condensate outlet pipeline, and a first steam trap is provided on the first condensate outlet pipeline; one end of the first outer coil is connected to a first outer coil steam inlet pipeline and the other end is connected to a second condensate outlet pipeline, and a second steam trap is provided on the second condensate outlet pipeline.

[0007] Preferably, the second heat exchanger includes a second heat exchange tube in the tube side and a second outer coil wound around the outside of the shell side; one end of the second heat exchange tube is connected to a second circulating water inlet pipeline and the other end is connected to a second circulating water outlet pipeline for circulating water to be introduced for cooling; the second heat exchange tube is connected to a second heat exchange tube steam inlet pipeline, and the second heat exchange tube condensate outlet is also connected to a third condensate outlet pipeline, and a third steam trap is provided on the third condensate outlet pipeline; one end of the second outer coil is connected to a second outer coil steam inlet pipeline and the other end is connected to a fourth condensate outlet pipeline, and a fourth steam trap is provided on the fourth condensate outlet pipeline.

[0008] Preferably, the first gas inlet pipeline is provided with a first shut-off valve and a first pressure gauge PT1, the first gas outlet pipeline is provided with a second shut-off valve and a second pressure gauge PT2, and the first gas outlet is provided with a thermometer TE3; the lower middle part of the shell side of the first heat exchanger is provided with thermometers TE1 and TE2 and level gauges L1 and L2; and the bottom cavity of the shell side of the first heat exchanger is connected to a first sulfur discharge valve.

[0009] Preferably, the second gas inlet pipeline is equipped with a third shut-off valve and a fourth pressure gauge PT4, the second gas outlet pipeline is equipped with a fourth shut-off valve and a fifth pressure gauge PT5, and a thermometer TE6 is provided at the second gas outlet; thermometers TE4 and TE5 and level gauges L3 and L4 are provided in the lower middle part of the shell side of the second heat exchanger; and a second sulfur discharge valve is connected to the bottom cavity of the shell side of the second heat exchanger.

[0010] Preferably, the upper air outlet of the first filter is connected to a first air outlet pipeline, and a third pressure gauge PT3 is installed on the first air outlet pipeline; the upper air outlet of the second filter is connected to a second air outlet pipeline, and a sixth pressure gauge PT6 is installed on the second air outlet pipeline.

[0011] The present invention also provides a method for sulfur recovery from crude hydrogen sulfide gas using any of the above-described systems, comprising the following steps: (a) The crude hydrogen sulfide gas is introduced into the shell side of the first heat exchanger through the first inlet pipeline and the first shut-off valve, while circulating water is introduced into the first heat exchange tube. The circulating water enters from the first circulating water inlet pipeline and flows out from the first circulating water outlet pipeline, cooling the gas to below 40°C, causing the molten sulfur to crystallize and settle into the bottom cavity; the cooled gas enters the first filter from the first gas outlet pipeline, where the high-precision filter element intercepts residual sulfur powder. (b) Monitor the reading of thermometer TE3, the pressure difference between the first pressure gauge PT1 and the second pressure gauge PT2, and the status of level gauge L1 in real time; (c) The first heat exchanger is deemed to require desulfurization treatment if any of the following conditions are met: TE3>40℃, PT1–PT2≥set threshold or L1 trigger high liquid level alarm; (d) Close the first shut-off valve and the second shut-off valve to cut off the flow between the first gas inlet pipeline and the first gas outlet pipeline, and stop supplying circulating water to the first circulating water inlet pipeline; (e) Start the steam supply so that steam enters the first heat exchange tube through the steam inlet pipeline of the first heat exchange tube and simultaneously enters the first outer coil through the steam inlet pipeline of the first outer coil; the generated condensate is discharged through the first condensate outlet pipeline and the second condensate outlet pipeline and through the first steam trap and the second steam trap, respectively. (f) Monitor thermometers TE1 and TE2. After the shell side temperature rises to between 135°C and 140°C and stabilizes, open the first sulfur discharge valve to allow molten sulfur to be discharged into the sulfur collection tank through the first sulfur discharge valve. (g) When the level gauge L2 indicates a low level, confirm that the sulfur removal is complete; (h) Close the steam inlet pipeline of the first heat exchange tube and the steam inlet pipeline of the first external coil, restore the circulation water supply to the first circulating water inlet pipeline, and switch the first heat exchanger to standby status; (i) Start the second heat exchanger simultaneously and repeat steps (a) to (h) above to maintain continuous system operation; (j) When the pressure difference between the second pressure gauge PT2 and the third pressure gauge PT3 or the fifth pressure gauge PT5 and the sixth pressure gauge PT6 is greater than or equal to the set threshold, the air intake of the currently running filter is cut off, and the standby filter is switched to operation. The original running filter is taken out of operation, and after cleaning or replacing the filter bag, it is put into standby mode. (K) Repeat the above process to achieve continuous interception, melting, and recovery of sulfur in crude hydrogen sulfide gas and continuous operation of the equipment.

[0012] Preferably, before step (d), nitrogen is introduced to purge the heat exchanger with an inert gas, which can ensure operational safety and pressurize the system to facilitate sulfur removal.

[0013] Preferably, the set thresholds include: an outlet temperature threshold of 40°C, corresponding to the reading of thermometer TE3 or TE6; a heat exchanger shell-side differential pressure threshold of 0.08–0.10 MPa, corresponding to the difference between PT1 and PT2 of the first heat exchanger, or the difference between PT4 and PT5 of the second heat exchanger; and a filter differential pressure threshold of 0.08–0.10 MPa, corresponding to the difference between PT2 and PT3 of the first filter, or the difference between PT5 and PT6 of the second filter.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention effectively solves the core problem of molten sulfur crystallizing and clogging pipelines and equipment under low-temperature conditions by constructing a parallel operation system of "dual heat exchangers + dual filters" and integrating key technologies such as cooling crystallization, sulfur vaporization, multi-parameter intelligent criteria, and precision filtration. Compared with existing technologies, it has the following significant advantages: (1) The present invention adopts a two-stage synergistic recovery mechanism: the first stage uses controlled cooling to allow molten sulfur to crystallize and settle in the shell side of the heat exchanger; the second stage uses a filter to intercept the escaped sulfur powder. This design prevents sulfur from entering the subsequent distillation column or cryogenic pipeline at the source, avoiding safety hazards such as tray blockage, sudden pressure drop and equipment overpressure, and significantly improving the reliability of the entire hydrogen sulfide synthesis and separation system.

[0015] (2) Two heat exchange-filtration units are set up in parallel. When one unit is in the cooling and recovery state, the other unit can independently complete the steam sulfurization, sulfur discharge and reset operations without interrupting the main airflow. This "run-regeneration" alternating mode eliminates the unplanned shutdown caused by sulfur removal in the traditional process, realizes the continuous operation of the sulfur recovery process, and significantly improves the utilization rate of the equipment.

[0016] (3) The system is based on three signals: outlet temperature (TE3 / TE6>40℃), shell-side pressure difference (PT1-PT2 or PT4-PT5 ≥ 0.08~0.10 MPa), and high liquid level switch (L1 / L3 alarm). The switching logic is automatically triggered when any one of these conditions is met. This monitoring mechanism ensures that the heat exchanger switches in a timely manner under optimal saturation conditions, preventing excessive sulfur accumulation and avoiding premature switching that would waste resources, thus achieving both safety and economy.

[0017] (4) The same heat exchange pipeline can be alternately circulated with circulating water (cooling) or steam (heating), and with the auxiliary heating of the outer coil wound around the shell side, the sulfur in the heat exchange tube wall and dead corner area is ensured to melt. This "one device for two purposes" design eliminates the need for additional sulfur removal equipment, saves investment and space, and at the same time automatically discharges condensate through the steam trap to ensure steam heating efficiency.

[0018] (5) The recovered liquid sulfur can be used in the H2S synthesis process or sold as a by-product, realizing resource recycling; the filter adopts a replaceable or washable high-precision filter element, which extends the service life and reduces the cost of consumables. The whole system significantly reduces raw material loss and solid waste discharge while ensuring safe production, which meets the green transformation requirements of modern chemical industry of "energy saving, consumption reduction, pollution reduction and efficiency improvement".

[0019] All switching actions (valve switching, medium switching, sulfur discharge control) can be executed by the DCS / PLC system according to preset thresholds, supplemented by safety measures such as nitrogen purging, significantly reducing the intensity of manual intervention and operational risks. This makes it suitable for application in hydrogen sulfide production units of different scales.

[0020] In summary, this invention fundamentally solves the sulfur blockage problem in crude hydrogen sulfide gas treatment, achieving the goal of safe, continuous, efficient, and green sulfur recovery, and has outstanding practicality and broad industrial application prospects. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a sulfur recovery system from crude hydrogen sulfide gas. In the diagram: 1 First heat exchanger, 11 First inlet pipeline, 111 First gas inlet, 112 First shut-off valve, 113 First pressure gauge PT1, 12 First gas outlet pipeline, 121 First gas outlet, 122 Second shut-off valve, 123 Thermometer TE3, 124 Second pressure gauge PT2, 13 First heat exchange tube, 131 First circulating water inlet pipeline, 132 First circulating water outlet pipeline, 133 First heat exchange tube steam inlet pipeline, 134 First condensate outlet pipeline, 135 First steam trap, 14 First external coil, 141 First external coil steam inlet pipeline, 142 Second condensate outlet pipeline, 143 Second steam trap, 15 First sulfur discharge valve, 16 Thermometer TE1, 17 Thermometer TE2, 18 Level gauge L1, 19 Level gauge L2, 3 First filter, 31 First gas outlet pipeline, 32 Seventh pressure gauge, 33 Third pressure gauge PT3; 2 Second heat exchanger, 21 Second inlet pipeline, 211 Second gas inlet, 212 Third shut-off valve, 213 Fourth pressure gauge PT4, 22 Second gas outlet pipeline, 221 Second gas outlet, 222 Fourth shut-off valve, 223 Thermometer TE6, 224 Fifth pressure gauge PT5, 23 Second heat exchange tube, 231 Second circulating water inlet pipeline, 232 Second circulating water outlet pipeline, 233 Second heat exchange tube steam inlet pipeline, 234 Third condensate outlet pipeline, 235 Third steam trap, 24 Second external coil, 241 Second external coil steam inlet pipeline, 242 Fourth condensate outlet pipeline, 243 Fourth steam trap, 25 Second sulfur discharge valve, 26 Thermometer TE4, 27 Thermometer TE5, 28 Level gauge L3, 29 Level gauge L4, 4 Second filter, 41 Second outlet pipeline, 42 Eighth pressure gauge, 43 Sixth pressure gauge PT6 Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. This invention relates to circuits, electronic components, and modules, all of which are prior art and can be fully implemented by those skilled in the art.

[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0026] Unless otherwise specified, all materials and reagents used in the following examples are commercially available. Example 1

[0027] This invention provides a sulfur recovery system from crude hydrogen sulfide gas. The technical solution of this invention will be further described below with reference to the accompanying drawings: See Figure 1 As shown, the crude hydrogen sulfide gas processed in this embodiment comes from an industrial sulfur and hydrogen catalytic synthesis unit, with operating conditions of 0.3–0.6 MPa and 350°C. The gas contains approximately 0.1% molten sulfur vapor and trace amounts of unreacted sulfur particles. To prevent crystallization and equipment blockage during subsequent low-temperature separation processes, efficient desulfurization treatment is required before it enters the distillation system.

[0028] The sulfur recovery system for crude hydrogen sulfide gas described in this invention includes a first heat exchanger 1, a second heat exchanger 2, a first filter 3, and a second filter 4. The first heat exchanger 1 and the second heat exchanger 2 are connected in parallel to alternately cool and crystallize the crude hydrogen sulfide gas. Each heat exchanger includes a shell side and a tube side structure. The crude hydrogen sulfide gas enters the shell side of the heat exchanger from the lower middle section, is cooled within the shell side, and then exits from the upper gas outlet, subsequently entering the corresponding filter for secondary purification.

[0029] In this embodiment: the first heat exchanger 1 has a first gas inlet 111 in the lower part of its shell side, which is connected to the first inlet pipeline 11; and a first gas outlet 121 in the upper part of its shell side, which is connected to the first gas outlet pipeline 12, and this pipeline is further connected to the inlet of the first filter 3. The second heat exchanger 2 has a second gas inlet 211 in the lower part of its shell side, which is connected to the second inlet pipeline 21; and a second gas outlet 221 in the upper part of its shell side, which is connected to the second gas outlet pipeline 22, and this pipeline is connected to the inlet of the second filter 4. The first filter 3 and the second filter 4 are arranged in parallel to alternately intercept residual sulfur powder in the gas after the heat exchanger treatment, ensuring that the outlet gas is clean.

[0030] In this embodiment, to achieve the dual functions of cooling and desulfurization of the heat exchanger, each heat exchanger is equipped with internal heat exchange tubes and external coils: The first heat exchanger 1 includes a first heat exchange tube 13 inside the tube side and a first outer coil 14 wound around the outside of the shell side. One end of the first heat exchange tube 13 is connected to a first circulating water inlet line 131 and the other end is connected to a first circulating water outlet line 132, for introducing circulating water to cool the shell-side gas; at the same time, the first heat exchange tube 13 is also connected to a first heat exchange tube steam inlet line 133, for introducing steam for heating during the desulfurization stage; its condensate outlet is connected to a first condensate outlet line 134, which is equipped with a first steam trap 135 to automatically discharge condensate. One end of the first outer coil 14 is connected to the first outer coil steam inlet line 141 and the other end is connected to a second condensate outlet line 142, which is equipped with a second steam trap 143.

[0031] The second heat exchanger 2 includes a second heat exchange tube 23 in the tube side and a second outer coil 24 wound around the outside of the shell side. One end of the second heat exchange tube 23 is connected to the second circulating water inlet line 231, and the other end is connected to the second circulating water outlet line 232, for circulating water to be introduced for cooling; at the same time, the second heat exchange tube 23 is connected to the second heat exchange tube steam inlet line 233, for introducing steam for heating during the sulfurization stage; its condensate outlet is also connected to the third condensate outlet line 234, which is equipped with a third steam trap 235 to automatically discharge condensate. One end of the second outer coil 24 is connected to the second outer coil steam inlet line 241, and the other end is connected to the fourth condensate outlet line 242, which is equipped with a fourth steam trap 243.

[0032] It should be noted that cooling the gas to below 40°C (far below the freezing point of sulfur, 112.8°C) ensures that the molten sulfur is fully condensed into solid crystals and significantly reduces its vapor partial pressure, preventing it from re-vaporizing or forming fine suspended particles in subsequent pipelines or filters. This improves sulfur recovery efficiency and protects downstream equipment.

[0033] In this embodiment, to achieve process monitoring and safety control, instruments and valves are installed at key locations in the system: The first inlet pipeline 11 is equipped with a first shut-off valve 112 and a first pressure gauge PT1 113 for controlling the intake and monitoring the inlet pressure; the first gas outlet pipeline 12 is equipped with a second shut-off valve 122 and a second pressure gauge PT2 124, and a thermometer TE3 123 is installed at the outlet 121; the lower middle part of the shell side of the first heat exchanger 1 is equipped with thermometers TE1 16 and TE2 17 and level gauges L118 and L2 19 for monitoring the internal temperature distribution and sulfur level; the bottom cavity of the shell side of the first heat exchanger 1 is connected to a first sulfur discharge valve 15 for discharging molten sulfur.

[0034] The second air inlet pipeline 21 is equipped with a third shut-off valve 212 and a fourth pressure gauge PT4 213 for controlling the air intake and monitoring the inlet pressure; the second gas outlet pipeline 22 is equipped with a fourth shut-off valve 222 and a fifth pressure gauge PT5 224, and a thermometer TE6 223 is installed at the outlet 221; thermometers TE4 26 and TE5 27 and level gauges L328 and L4 29 are installed in the lower middle part of the shell side of the second heat exchanger 2 for monitoring the internal temperature distribution and sulfur level; the bottom cavity of the shell side of the second heat exchanger 2 is connected to a second sulfur discharge valve 25.

[0035] Pressure monitoring points are also installed at the filter outlets: the upper outlet of the first filter 3 is connected to the first outlet pipeline 31, which is equipped with a third pressure gauge PT3 33; the second filter 4 is equipped with a second outlet pipeline 41 and a sixth pressure gauge PT6 43, used to calculate the pressure difference before and after the filter and determine the degree of filter element blockage. The first filter 3 and the second filter 4 contain sintered metal filter elements (or polytetrafluoroethylene membrane filter bags) with an accuracy of 10μm, which can effectively intercept micron-sized sulfur particles. Example 2

[0036] This embodiment describes a process for recovering sulfur from crude hydrogen sulfide gas using the system provided in Example 1. The specific operation steps are as follows: (1) First, crude hydrogen sulfide gas enters the shell side of the first heat exchanger 1 through the first inlet pipeline 11 and the first shut-off valve 112. At the same time, circulating water (inlet from 131 and outlet from 132) is introduced into the first heat exchange tube 13 to cool the gas to below 40°C, causing molten sulfur to crystallize and settle into the bottom cavity of the shell side. The cooled gas enters the first filter 3 through the first gas outlet pipeline 12, where residual sulfur powder is intercepted by the high-precision filter element.

[0037] (2) The system monitors the temperature of TE3 123, the pressure difference between PT1 113 and PT2 124, and the liquid level of L1 18 in real time. When any of the following conditions are met—TE3>40℃, PT1–PT2 ≥ the set threshold, or L1 triggers a high liquid level alarm—it is determined that the first heat exchanger 1 has reached sulfur saturation and needs to be treated with sulfur.

[0038] (3) At this time, the first shut-off valve 112 and the second shut-off valve 122 are closed to cut off the gas path and stop the supply of circulating water; preferably, nitrogen is introduced to replace the first heat exchanger 1 with inert gas and pressurize it to 0.2-0.25 MPa, which not only ensures the safety of operation, but also facilitates the smooth discharge of sulfur in the future; then the steam is turned on, so that the steam enters the heat exchanger tube and the outer coil through the steam inlet pipeline 133 of the first heat exchange tube and the steam inlet pipeline 141 of the first outer coil respectively, to heat the shell side as a whole; the condensate is automatically discharged by the steam traps (135, 143) through the first condensate outlet pipeline 134 and the second condensate outlet pipeline 142 respectively.

[0039] (4) After the shell side temperature (monitored by TE1 and TE2) rises to 135-140℃ and stabilizes, open the first sulfur discharge valve 15 to discharge molten sulfur into the collection tank; when L2 19 indicates low liquid level, confirm that sulfur discharge is complete. Then shut off the steam, restore the circulating water, and switch the first heat exchanger 1 to standby.

[0040] (5) At the same time, the second heat exchanger 2 is put into operation and performs the same cooling, monitoring and desulfurization operation process as the first heat exchanger 1, thereby achieving continuous and stable operation of the system. In addition, when the filter differential pressure (PT2–PT3 or PT5–PT6) ≥ the set threshold, the air intake of the currently operating filter is cut off, and the standby filter is switched to operation. The original operating filter is taken out of operation, and after cleaning or replacement of the filter bag, it is put into standby mode. Preferably, the outlet temperature threshold is 40°C, corresponding to the reading of thermometer TE3 or TE6; the heat exchanger shell-side differential pressure threshold is 0.08 to 0.10 MPa, corresponding to the difference between PT1 and PT2 of the first heat exchanger 1, or the difference between PT4 and PT5 of the second heat exchanger 2; the filter differential pressure threshold is 0.08 to 0.10 MPa, corresponding to the difference between PT2 and PT3 of the first filter 3, or the difference between PT5 and PT6 of the second filter 4.

[0041] In this embodiment, all switching actions can be automatically executed by the DCS or PLC control system. The typical operating cycle of the two units is 8 to 24 hours, which is dynamically adjusted according to the feed sulfur load.

[0042] In summary, this invention achieves the interception, efficient recovery, continuous operation, and safety of sulfur in crude hydrogen sulfide gas through a two-stage interception process of "cooling crystallization + precision filtration" and parallel switching of "dual heat exchangers + dual filters," and has broad industrial application value.

[0043] The present invention provides a detailed description of a sulfur recovery system and method for crude hydrogen sulfide gas. Specific examples have been used to illustrate the principles and implementation methods of the invention. These examples are merely illustrative and are intended to aid in understanding the method and core concepts of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A sulfur recovery system from crude hydrogen sulfide gas, characterized in that, The system includes a first heat exchanger (1), a second heat exchanger (2), a first filter (3), and a second filter (4); the first heat exchanger (1) and the second heat exchanger (2) are arranged in parallel, and each heat exchanger includes a shell side and a tube side; the lower middle part of the shell side of the first heat exchanger (1) is provided with a first gas inlet (111), which is connected to a first gas inlet pipeline (11); the upper part of the shell side of the first heat exchanger (1) is provided with a first gas outlet (121), which is connected to a first gas outlet pipeline (12), which is connected to... The first filter (3) has an inlet; the second heat exchanger (2) has a second gas inlet (211) in the lower middle part of its shell side, and the second gas inlet (211) is connected to the second gas inlet pipeline (21); the second heat exchanger (2) has a second gas outlet (221) in the upper part of its shell side, and the second gas outlet (221) is connected to the second gas outlet pipeline (22), and the second gas outlet pipeline (22) is connected to the inlet of the second filter (4); the first filter (3) and the second filter (4) are arranged in parallel to alternately intercept the sulfur powder remaining in the gas after the heat exchanger is processed.

2. The sulfur recovery system from crude hydrogen sulfide gas according to claim 1, characterized in that, The first heat exchanger (1) includes a first heat exchange tube (13) inside the tube side and a first outer coil (14) wound around the outside of the shell side; one end of the first heat exchange tube (13) is connected to a first circulating water inlet pipeline (131) and the other end is connected to a first circulating water outlet pipeline (132) for circulating water to be introduced for cooling; the first heat exchange tube (13) is connected to a first heat exchange tube steam inlet pipeline (133), and the condensate outlet of the first heat exchange tube (13) is also connected to a first condensate outlet pipeline (134), and a first steam trap (135) is provided on the first condensate outlet pipeline (134); one end of the first outer coil (14) is connected to a first outer coil steam inlet pipeline (141) and the other end is connected to a second condensate outlet pipeline (142), and a second steam trap (143) is provided on the second condensate outlet pipeline (142).

3. The sulfur recovery system from crude hydrogen sulfide gas according to claim 1, characterized in that, The second heat exchanger (2) includes a second heat exchange tube (23) inside the tube side and a second outer coil (24) wound around the outside of the shell side; one end of the second heat exchange tube (23) is connected to the second circulating water inlet pipeline (231) and the other end is connected to the second circulating water outlet pipeline (232) for circulating water to be introduced for cooling; the second heat exchange tube (23) is connected to the second heat exchange tube steam inlet pipeline (233), and the condensate outlet of the second heat exchange tube (23) is also connected to the third condensate outlet pipeline (234), and the third condensate outlet pipeline (234) is provided with a third steam trap (235); one end of the second outer coil (24) is connected to the second outer coil steam inlet pipeline (241) and the other end is connected to the fourth condensate outlet pipeline (242), and the fourth condensate outlet pipeline (242) is provided with a fourth steam trap (243).

4. A sulfur recovery system from crude hydrogen sulfide gas according to claim 2, characterized in that, The first gas inlet pipeline (11) is equipped with a first shut-off valve (112) and a first pressure gauge PT1 (113), the first gas outlet pipeline (12) is equipped with a second shut-off valve (122) and a second pressure gauge PT2 (124), and a thermometer TE3 (123) is provided at the first gas outlet (121); the lower middle part of the shell side of the first heat exchanger (1) is equipped with thermometers TE1 (16) and TE2 (17) and level gauges L1 (18) and L2 (19); the bottom cavity of the shell side of the first heat exchanger (1) is connected to a first sulfur discharge valve (15).

5. A sulfur recovery system from crude hydrogen sulfide gas according to claim 3, characterized in that, The second gas inlet pipeline (21) is equipped with a third shut-off valve (212) and a fourth pressure gauge PT4 (213), the second gas outlet pipeline (22) is equipped with a fourth shut-off valve (222) and a fifth pressure gauge PT5 (224), and a thermometer TE6 (223) is provided at the second gas outlet (221); the lower middle part of the shell side of the second heat exchanger (2) is equipped with thermometers TE4 (26) and TE5 (27) and level gauges L3 (28) and L4 (29); the bottom cavity of the shell side of the second heat exchanger (2) is connected to a second sulfur discharge valve (25).

6. A sulfur recovery system from crude hydrogen sulfide gas according to claim 1, characterized in that, The first filter (3) has a first air outlet connected to a first air outlet line (31) at its upper air outlet, and a third pressure gauge PT3 (33) is provided on the first air outlet line (31); the second filter (4) has a second air outlet connected to a second air outlet line (41) at its upper air outlet, and a sixth pressure gauge PT6 (43) is provided on the second air outlet line (41).

7. A method for recovering sulfur from crude hydrogen sulfide gas using the system described in any one of claims 1 to 6, characterized in that, Includes the following steps: (a) The crude hydrogen sulfide gas is introduced into the shell side of the first heat exchanger (1) through the first inlet pipeline (11) and the first shut-off valve (112), while circulating water is introduced into the first heat exchange tube (13). The circulating water enters from the first circulating water inlet pipeline (131) and flows out from the first circulating water outlet pipeline (132), cooling the gas to below 40°C, causing the molten sulfur to crystallize and settle into the bottom cavity; the cooled gas enters the first filter (3) from the first gas outlet pipeline (12), where the high-precision filter element intercepts the residual sulfur powder. (b) Real-time monitoring of the reading of thermometer TE3 (123), the pressure difference between the first pressure gauge PT1 (113) and the second pressure gauge PT2 (124), and the status of level gauge L1 (18); (c) The first heat exchanger (1) is deemed to require sulfur treatment if any of the following conditions are met: TE3>40℃, PT1–PT2≥set threshold or L1 trigger high liquid level alarm; (d) Close the first shut-off valve (112) and the second shut-off valve (122) to cut off the flow between the first air inlet pipeline (11) and the first gas outlet pipeline (12), and stop supplying circulating water to the first circulating water inlet pipeline (131); (e) Start the steam supply so that steam enters the first heat exchange tube (13) through the steam inlet pipeline (133) and enters the first outer coil (14) through the steam inlet pipeline (141); the generated condensate is discharged through the first condensate outlet pipeline (134) and the second condensate outlet pipeline (142) and through the first steam trap (135) and the second steam trap (143); (f) Monitor thermometers TE1 (16) and TE2 (17). After the shell side temperature rises to between 135°C and 140°C and stabilizes, open the first sulfur discharge valve (15) to discharge molten sulfur into the sulfur collection tank through the first sulfur discharge valve (15). (g) When the level gauge L2 (19) indicates a low level, confirm that the sulfur removal is complete; (h) Close the steam inlet line (133) of the first heat exchange tube and the steam inlet line (141) of the first external coil, restore the flow of circulating water to the first circulating water inlet line (131), and switch the first heat exchanger (1) to standby status; (i) Start the second heat exchanger (2) synchronously and repeat steps (a) to (h) above to maintain continuous operation of the system; (j) When the pressure difference between the second pressure gauge PT2 (124) and the third pressure gauge PT3 (33) or the fifth pressure gauge PT5 (224) and the sixth pressure gauge PT6 (43) is greater than or equal to the set threshold, the air intake of the currently running filter is cut off, the standby filter is switched to operation, the original running filter is taken out of operation, and after cleaning or replacement of the filter bag, it is put into standby mode. (K) Repeat the above process to achieve continuous interception, melting, and recovery of sulfur in crude hydrogen sulfide gas and continuous operation of the equipment.

8. The method according to claim 7, characterized in that, Before step (d), nitrogen gas is introduced to purge the heat exchanger with an inert gas, which can ensure operational safety and pressurize the system to facilitate sulfur removal.

9. The method according to claim 7, characterized in that, The set thresholds include: an outlet temperature threshold of 40°C, corresponding to the reading of thermometer TE3 or TE6; a heat exchanger shell-side differential pressure threshold of 0.08 to 0.10 MPa, corresponding to the difference between PT1 and PT2 of the first heat exchanger (1), or the difference between PT4 and PT5 of the second heat exchanger (2); and a filter differential pressure threshold of 0.08 to 0.10 MPa, corresponding to the difference between PT2 and PT3 of the first filter (3), or the difference between PT5 and PT6 of the second filter (4).

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