Non-condensable gas treatment apparatus and method

Abstract

The application discloses a non-condensable gas treatment device and method, and relates to the technical field of sewage stripping separation. The device comprises: a stripping unit, which is used for separating sewage to obtain crude steam and purified water; a reflux tank, which is connected with the stripping unit and is used for separating the crude steam to obtain reflux sewage and non-condensable gas; a combustion unit, which is connected with the reflux tank and is used for burning the non-condensable gas separated by the reflux tank to obtain high-temperature harmless waste gas; and a steam unit, which is connected with the combustion unit and is used for generating medium-pressure steam through the high-temperature harmless waste gas. The non-condensable gas of the sewage stripping tower and the regenerated flue gas are jointly introduced into a burning furnace for high-temperature burning, so that oxygen-containing compounds such as acetone and dimethyl ether are completely decomposed into harmless substances; and the high-temperature harmless waste gas generated by burning is transported to the steam unit, the heat energy of the high-temperature harmless waste gas is used to generate medium-pressure steam, and the medium-pressure steam is connected to a network, so that resource utilization is realized.

Description

Technical Field

[0001] This application relates to the field of wastewater stripping and separation technology, and in particular to a non-condensable gas treatment device and method. Background Technology

[0002] Methanol to Olefins (MTO) is a chemical process that converts methanol into low-carbon olefins such as ethylene and propylene. In this process, methanol feedstock undergoes a catalytic reaction to produce olefin products, while simultaneously generating a large amount of process water containing pollutants. This process water needs to be purified using a wastewater stripping tower: steam is introduced from the bottom of the tower and comes into countercurrent contact with the wastewater flowing downwards, stripping volatile oxygen-containing compounds from the wastewater to the top of the tower to form non-condensable gases, while the purified water is discharged from the bottom. Effective treatment of non-condensable gases is a crucial step in ensuring the environmental friendliness of the entire process and the quality of downstream products.

[0003] Existing technologies typically return non-condensable gases to the reactor, attempting to decompose oxygen-containing compounds through secondary reactions. However, actual operation shows that oxygen-containing compounds cannot be completely converted; instead, they accumulate in the olefin separation system, ultimately leading to a decline in the quality of high-value-added products such as propane and mixed C4 due to excessive oxygen content. Furthermore, switching to a flare system for combustion in emergency situations, while avoiding the risk of reactor temperature fluctuations, causes oxygen-containing compounds in the non-condensable gases to condense into liquid in the low-temperature flare pipes, forcing them to return to the wastewater stripping tower for treatment, creating an ineffective cycle that cannot be broken. This exposes a key flaw in existing technology: oxygen-containing compounds cannot be completely eliminated and continue to pollute downstream product systems, becoming a bottleneck restricting the improvement of quality and efficiency in methanol-to-olefins processes. Summary of the Invention

[0004] In view of this, this application provides a non-condensable gas treatment device and method, the main purpose of which is to solve the technical problem that oxygen-containing compounds in existing non-condensable gas treatment technologies cannot be completely eliminated and continue to pollute downstream product systems.

[0005] On one hand, this application provides a non-condensable gas treatment apparatus, comprising: A stripping unit, wherein the stripping unit is used to separate wastewater to obtain crude steam and purified water; A reflux tank, connected to the stripping unit, is used to separate crude steam to obtain reflux wastewater and non-condensable gas; A combustion unit, which is connected to the return tank, is used to burn the non-condensable gas separated by the return tank to obtain high-temperature harmless waste gas. A steam unit, connected to the combustion unit, is used to generate medium-pressure steam from high-temperature harmless waste gas.

[0006] In one feasible implementation, the device further includes: A feed heat exchanger, which is connected to the stripping unit, is used to receive and heat wastewater; A purified water pump is connected to the stripping unit and the feed heat exchanger, and is used to return the purified water separated by the stripping unit to the feed heat exchanger.

[0007] In one feasible implementation, the device further includes: A pressure regulating valve is provided on the connecting pipeline between the reflux tank and the combustion unit.

[0008] In one feasible implementation, the stripping unit includes: A stripping tower, which is connected to the feed heat exchanger and the reflux tank, is used to strip crude steam and generate purified water in the tower bottom; A reboiler, connected to the stripping tower, is used to heat purified water; A stripper heat exchanger, which is connected to the stripper tower and the reflux tank, is used to cool crude steam. A reflux pump is installed on the connecting pipeline between the stripping tower and the reflux tank, and is used to return reflux wastewater to the stripping tower.

[0009] In one feasible implementation, the device further includes: A non-condensable gas bypass line connects the reflux tank and the stripping unit, and is used to adjust the pressure difference between the reflux tank and the stripping tower; A secondary line valve is provided on the non-condensable gas secondary line.

[0010] In one feasible implementation, the combustion unit includes: An incinerator, which is connected to the reflux tank; An incineration pipeline, the incineration pipeline connecting the incinerator and the reflux tank; The first incineration valve and the second incineration valve are located on the incineration pipeline and are used to control the flow of non-condensable gas into the incinerator. A regenerated flue gas pipeline, which is connected to the incinerator, is used to introduce regenerated flue gas into the incinerator.

[0011] In one feasible implementation, the combustion unit further includes: Flare line, which is connected to the return tank; Flare valve, wherein the flare valve is located on the flare line; A remelting pipeline, which is connected to the reflux tank; A remelting valve is installed on the remelting pipeline; The flare line is connected in parallel with the remelting line and the incineration line.

[0012] In one feasible implementation, the device further includes: A blower, which is connected to the incinerator, is used to supply combustion air into the incinerator; An air valve is provided on the input pipe of the blower; A fuel gas pipeline network, which is connected to the incinerator, is used to ignite and start the incinerator; A fuel gas valve is provided on the fuel gas pipeline.

[0013] On the other hand, this application provides a method for treating non-condensable gases, including: Wastewater is separated to obtain crude steam through a stripping unit; The crude steam is fed into a reflux tank for separation to obtain non-condensable gas; Non-condensable gases are transported to the combustion unit for incineration to obtain high-temperature harmless waste gas; High-temperature harmless waste gas is treated by a steam unit to obtain medium-pressure steam.

[0014] In one feasible implementation, the method further includes: Wastewater is heated by the feed heat exchanger before entering the stripping tower; The reboiler heats the stripping tower with low-pressure steam to obtain crude steam and purified water; After being cooled by a stripper heat exchanger, the crude steam enters a reflux tank for separation, yielding reflux wastewater and non-condensable gas. The return pump sends the returned wastewater back to the stripping tower; Turn on the fuel gas valve, blower and incinerator, open the first incineration valve and the second incineration valve, and close the remelting valve and flare valve; Adjust the pressure regulating valve to mix the non-condensable gas with the regenerated flue gas, and then input the mixed gas into the incinerator for combustion; The high-temperature, harmless waste gas generated by incineration is transported to the steam unit to generate medium-pressure steam.

[0015] This application provides a non-condensable gas treatment device and method. The device includes: a stripping unit for separating wastewater to obtain crude steam and purified water; a reflux tank connected to the stripping unit for separating crude steam to obtain reflux wastewater and non-condensable gas; a combustion unit connected to the reflux tank for incinerating the non-condensable gas separated in the reflux tank to obtain high-temperature harmless waste gas; and a steam unit connected to the combustion unit for generating medium-pressure steam from the high-temperature harmless waste gas. This application introduces the non-condensable gas from the wastewater stripping tower and the regenerated flue gas into an incinerator for high-temperature incineration, completely decomposing oxygen-containing compounds such as acetone and dimethyl ether into harmless substances, eliminating the defects caused by their cyclic accumulation in the olefin separation system, which leads to pollution of products such as propane and mixed C4. Furthermore, this application also transports the high-temperature harmless waste gas generated from incineration to the steam unit, utilizing its thermal energy to produce medium-pressure steam for grid connection, transforming the pollutant treatment process into an energy recovery process, realizing resource utilization, and ensuring the stable operation of the oxygen-containing compound elimination pathway and energy recovery process under all process scenarios.

[0016] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0017] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This paper shows a schematic diagram of the structure of a non-condensable gas treatment device provided in an embodiment of this application; Figure 2 A schematic flowchart of a non-condensable gas treatment method provided in an embodiment of this application is shown; Figure 3 A schematic diagram of a specific process for a non-condensable gas treatment method provided in an embodiment of this application is shown.

[0019] In the picture: 1. Feed heat exchanger; 2. Stripping tower; 3. Purified water pump; 4. Stripping gas heat exchanger; 5. Reflux tank; 6. Reflux pump; 7. Reboiler; 8. Pressure regulating valve; 9. Flare valve; 10. Flare line; 11. Recycled gas valve; 12. Recycled gas line; 13. First combustion valve; 14. Second combustion valve; 15. Incinerator; 16. Fuel gas valve; 17. Fuel gas pipeline network; 18. Blower; 19. Air valve; 20. Sub-line valve; 21. Non-condensable gas sub-line; 22. Incineration line; 23. Regenerated flue gas line. Detailed Implementation

[0020] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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 limitations on this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In an industrial methanol-to-olefins (MTO) plant, methanol feedstock is preheated into a gas phase by a heat exchanger and enters a circulating fluidized bed reactor. Under the action of a molecular sieve catalyst, it is converted into low-carbon olefin products, mainly ethylene and propylene, while generating process wastewater containing methanol, dimethyl ether, and aldehydes and ketones. This wastewater is condensed in a quench water scrubber and then separated in a settling tank before being transported to a wastewater stripping tower equipped with a high-efficiency floating valve tray for stripping. Gas-liquid separation is achieved by heating with low-pressure steam in a reboiler. This process generates non-condensable gas with acetone and dimethyl ether as the main components at the top of the tower, while purified water is output from the bottom. At the same time, the deactivated catalyst in the reaction system cokes to generate a large amount of high-temperature regenerated flue gas rich in CO. This flue gas is transported to a CO incinerator for oxidation treatment through a regenerated flue gas pipeline. However, existing technologies treat stripping noncondensable gas and regenerated flue gas separately: the noncondensable gas is forced to be recycled back to the reactor, resulting in the accumulation of oxygen-containing compounds in the olefin separation system or their emission into the flare system, forming secondary pollution of the condensate. This has always been unable to break through the dilemma that oxygen-containing compounds both pollute downstream products and cannot be utilized as resources.

[0024] See Figure 1 This application illustrates a non-condensable gas treatment apparatus according to an embodiment of the present application, comprising: The stripping unit is used to separate wastewater to obtain crude steam and purified water. Return tank 5 is connected to the stripping unit and is used to separate crude steam to obtain return wastewater and non-condensable gas; The combustion unit is connected to the return tank 5 and is used to incinerate the non-condensable gas separated in the return tank 5 to obtain high-temperature harmless waste gas. The steam unit, connected to the combustion unit, is used to generate medium-pressure steam from high-temperature, harmless waste gas.

[0025] In the above embodiment, the stripping unit receives oxygenated wastewater from upstream via a pipeline and performs stripping separation internally. The inlet of the reflux tank 5 is connected to the top outlet of the stripping unit via a vapor phase pipeline, receiving the crude steam generated by the stripping unit. The inlet pipeline of the combustion unit is connected to the vapor phase outlet at the top of the reflux tank 5, receiving the non-condensable gas separated by the reflux tank 5. The outlet of the combustion unit is connected to the flue gas inlet of the steam unit, introducing the high-temperature harmless waste gas generated by combustion into the steam unit. The steam outlet of the steam unit outputs medium-pressure steam generated by recovering heat energy.

[0026] This structure enables the efficient separation and direct incineration of non-condensable gases in wastewater. By incorporating a steam unit, the heat energy contained in the high-temperature, harmless waste gas generated from the combustion of non-condensable gases can be effectively recovered and utilized, converting it into valuable medium-pressure steam. This significantly improves the energy utilization efficiency of the entire process, achieves cascaded energy utilization, reduces the operating energy consumption of the unit, and ensures the complete and harmless treatment of pollutants.

[0027] Furthermore, the device also includes: Feed heat exchanger 1 is connected to the stripping unit and is used to receive and heat wastewater; Purified water pump 3 is connected to the stripping unit and the feed heat exchanger 1 and is used to return the purified water separated by the stripping unit to the feed heat exchanger 1.

[0028] In the above embodiment, the tube-side inlet of the feed heat exchanger 1 is used to receive wastewater to be treated, and its tube-side outlet is connected to the inlet of the stripping unit via a pipeline. The purified water outlet of the stripping unit is connected to the inlet of the purified water pump 3. The outlet pipeline of the purified water pump 3 is divided into two paths: one path is used to output qualified purified water, and the other path is connected to the shell-side inlet of the feed heat exchanger 1 via a reflux valve. The shell-side outlet of the feed heat exchanger 1 discharges the purified water that has completed heat exchange.

[0029] The high-temperature purified water generated in the stripping unit's reboiler is pumped back to the shell side of the feed heat exchanger 1 by the purified water pump 3, where it exchanges heat with the cold wastewater entering the tube side. This design fully utilizes the waste heat of the purified water to preheat the feed wastewater, significantly reducing the external heating load required by the stripping unit, reducing steam consumption, and significantly improving the overall system's thermal efficiency and economy. Simultaneously, the preheated wastewater entering the stripping unit facilitates smoother stripping operations.

[0030] Furthermore, the device also includes: Pressure regulating valve 8 is located on the connecting pipeline between the return tank 5 and the combustion unit.

[0031] In the above embodiment, the pressure regulating valve 8 is installed on the main pipeline from the top of the non-condensable gas return tank 5 to the combustion unit. The control end of this valve can be connected to the control system to automatically or manually adjust the valve opening according to process requirements.

[0032] The pressure regulating valve 8 allows operators to precisely control the flow rate and pressure of non-condensable gas entering the combustion unit from the return tank 5. This ensures that the non-condensable gas is delivered to the incinerator 15 at a stable and controllable flow rate, avoiding the adverse effects of flow fluctuations on the combustion stability of the incinerator. It also ensures that oxygenated compounds receive sufficient and continuous combustion conditions in the incinerator, maintaining the safe and efficient operation of the unit.

[0033] Furthermore, the stripping unit includes: Stripping tower 2 is connected to feed heat exchanger 1 and reflux tank 5. It is used to strip crude steam and generate purified water in the tower bottom. Reboiler 7 is connected to stripper 2 and is used to heat purified water; The stripper heat exchanger 4 is connected to the stripper tower 2 and the reflux tank 5 and is used to cool the crude steam. The reflux pump 6 is located on the connecting pipeline between the stripping tower 2 and the reflux tank 5, and is used to return the reflux wastewater to the stripping tower.

[0034] In the above embodiment, the feed inlet of the stripping tower 2 is located at the top of the tower body and is connected to the tube-side outlet of the feed heat exchanger 1 via a pipeline. The top vapor outlet of the stripping tower 2 is connected to the hot-side inlet of the stripping gas heat exchanger 4. The hot-side outlet of the stripping gas heat exchanger 4 is connected to the top inlet of the reflux tank 5. The bottom liquid outlet of the reflux tank 5 is connected to the inlet of the reflux pump 6 via a pipeline, and the outlet of the reflux pump 6 is connected to the reflux inlet at the top of the stripping tower 2. One path of the bottom liquid outlet of the stripping tower 2 is connected to the tube-side inlet of the reboiler 7, and the tube-side outlet of the reboiler 7 returns to the bottom of the stripping tower 2; the other path is connected to the purified water pump 3. The shell side of the reboiler 7 is supplied with external heat source steam.

[0035] This stripping unit structure forms a highly efficient separation and reflux cycle. The reboiler 7 uses external steam to indirectly heat the purified water in the column bottom, providing a stable heat source for the stripping process. The stripping gas heat exchanger 4 uses a cold medium to cool the crude steam at the top of the column, promoting the condensation of condensable components. The reflux tank 5 achieves gas-liquid separation; the separated non-condensable gas enters the subsequent treatment unit, while the condensed liquid reflux wastewater is pressurized by the reflux pump 6 and pumped back, in whole or in part, to the top of the stripping column 2 as reflux. This design ensures that the wastewater achieves sufficient stripping effect within the column, significantly improving the separation efficiency of oxygen-containing non-condensable gas components from the wastewater, while also ensuring efficient removal of moisture from the top steam, providing a solid foundation for the stable treatment of subsequent non-condensable gases and the achievement of purified water standards.

[0036] Furthermore, the device also includes: Non-condensable gas sub-line 21 connects the reflux tank 5 and the stripping unit, and is used to adjust the pressure difference between the reflux tank 5 and the stripping tower 2. Sub-line valve 20 is installed on non-condensable gas sub-line 21.

[0037] In the above embodiment, the non-condensable gas bypass line 21 is a bypass pipeline connecting the top gas phase space of the stripping tower 2 and the top gas phase space of the reflux tank 5. The bypass valve 20 is installed on this bypass pipeline, and is usually a regulating valve, whose control end can be connected to the control system.

[0038] The non-condensable gas bypass line 21 and bypass valve 20 provide a flexible pressure balancing mechanism. By adjusting the opening of bypass valve 20, the pressure difference between the top pressure of stripping tower 2 and the pressure inside reflux tank 5 can be actively and precisely controlled. This effectively avoids problems such as poor gas phase transport, liquid seal failure, or even equipment damage caused by pressure fluctuations or excessive pressure difference, ensuring the stable and safe operation of the stripping unit and reflux system, especially when switching between different operating conditions or changing loads.

[0039] Furthermore, the combustion unit includes: Incinerator 15, which is connected to reflux tank 5; Incineration pipeline 22 connects incinerator 15 and reflux tank 5; The first combustion valve 13 and the second combustion valve 14 are installed on the combustion pipeline 22 and are used to control the flow of non-condensable gas into the incinerator 15. The regenerated flue gas pipeline 23 is connected to the incinerator 15 and is used to introduce regenerated flue gas into the incinerator 15.

[0040] In the above embodiment, the inlet end of the incineration line 22 is connected to the non-condensable gas output line at the top of the return tank 5 after the pressure regulating valve 8. The outlet end of the incineration line 22 is connected to the burner inlet or a specific location in the furnace of the incinerator 15. The first incineration valve 13 and the second incineration valve 14 are installed in series on the incineration line 22. The outlet end of the regenerated flue gas line 23 is connected to the incinerator 15, typically near the burner or at the top of the furnace. The flue gas outlet of the incinerator 15 is connected to the flue gas inlet of the steam unit, and the steam outlet of the steam unit outputs medium-pressure steam.

[0041] The combustion unit features an ingenious structural design. By installing two valves, the first combustion valve 13 and the second combustion valve 14, on the combustion pipeline 22, dual isolation and safe shut-off of the non-condensable gas entering the incinerator 15 are achieved, improving operational reliability and safety. Crucially, the introduction of the regenerated flue gas pipeline 23 into the incinerator 15 allows the high-temperature regenerated flue gas rich in CO to mix and burn with the oxygen-containing non-condensable gas within the furnace. The non-condensable gas itself has a high calorific value; when mixed with the high-temperature regenerated flue gas, it not only provides a sufficient environment for the oxidation and decomposition of the oxygen-containing compounds in the non-condensable gas but also significantly increases the combustion temperature of the mixture, ensuring that the oxygen-containing compounds are completely decomposed into harmless CO2 and H2O. Simultaneously, the heat energy released by combustion is efficiently recovered by the steam unit to generate medium-pressure steam, maximizing energy utilization and completely eliminating the fundamental problem of oxygen-containing compounds circulating and accumulating within the system, thus guaranteeing the quality of the final product.

[0042] Furthermore, the combustion unit also includes: Flare line 10 is connected to reflux tank 5; Flare valve 9 is installed on flare line 10; The remelting pipeline 12 is connected to the reflux tank 5; Recycle valve 11 is installed on recycle pipeline 12; Flare line 10 is connected in parallel with remelting line 12 and incineration line 22.

[0043] In the above embodiment, the inlet ends of flare line 10, recycle line 12, and incineration line 22 are all connected in parallel to the same non-condensable gas output main on the top of reflux tank 5, located before pressure regulating valve 8. Flare valve 9 is installed on flare line 10, and recycle valve 11 is installed on recycle line 12. The outlet end of flare line 10 is connected to the flare system of the unit. The outlet end of recycle line 12 is connected to the reactor inlet or its recycle system.

[0044] This parallel three-path configuration provides comprehensive adaptability to various operating conditions and emergency response capabilities for the treatment of non-condensable gases. By operating the corresponding valve groups—first incineration valve 13, second incineration valve 14, recycle valve 11, and flare valve 9—the most suitable treatment path can be flexibly selected according to the actual operating status of the unit: during normal operation, incineration is prioritized, with the incineration valve opened and the recycle valve and flare valve closed to completely decompose oxygen-containing compounds; in case of an accident, flare discharge can be quickly switched, with the flare valve opened and other valves closed; and under specific process requirements, recycle to the reactor can also be selected, with the recycle valve opened and other valves closed. This design greatly enhances the stability and operational flexibility of the entire unit, ensuring that non-condensable gases can be safely and effectively disposed of under any operating condition, preventing system pressure runaway or improper handling of oxygen-containing compounds.

[0045] Furthermore, the device also includes: Blower 18 is connected to incinerator 15 and is used to supply combustion air into incinerator 15; Air valve 19 is located on the input pipe of blower 18; Fuel gas pipeline 17 is connected to incinerator 15 and is used to ignite and start incinerator 15. Fuel gas valve 16 is located on fuel gas pipeline 17.

[0046] In the above embodiment, the outlet of the blower 18 is connected to the air distribution port or burner inlet of the incinerator 15 via an air supply duct. An air valve 19 is installed on the inlet pipe of the blower 18 to control the air supply. The fuel gas network 17 is connected to the fuel nozzle of the incinerator 15 via a gas supply line. A fuel gas valve 16 is installed on this gas supply line to control the fuel gas supply. The control terminals of both the fuel gas valve 16 and the air valve 19 can be connected to a control system.

[0047] Blower 18 and air valve 19 constitute a system for supplying combustion air to incinerator 15, ensuring that non-condensable gases and regenerated flue gas receive sufficient oxygen in the furnace for complete combustion. Fuel gas pipeline 17 and fuel gas valve 16 constitute the ignition and auxiliary fuel system for incinerator 15. During the incinerator start-up phase or when the calorific value of non-condensable gases is insufficient to maintain the furnace temperature, fuel gas valve 16 can be opened to introduce fuel gas for ignition or auxiliary combustion. The installation of these auxiliary systems ensures that incinerator 15 can be reliably ignited under various conditions and can flexibly adjust the combustion state according to changes in non-condensable gas flow and composition, maintaining a continuous high-temperature oxidation environment in the furnace, thereby ensuring that oxygen-containing compounds in non-condensable gases always receive thorough and stable decomposition conditions, ultimately achieving the goal of harmless emission.

[0048] See Figure 2 and Figure 3 The diagram shows a flow chart of a non-condensable gas treatment method provided in an embodiment of this application, including: 101. Sewage is separated to obtain crude steam through a stripping unit; 102. The crude steam is fed into the reflux tank for separation to obtain non-condensable gas; 103. Non-condensable gases are transported to the combustion unit for incineration to obtain high-temperature harmless waste gas; 104. High-temperature harmless waste gas is treated by a steam unit to obtain medium-pressure steam.

[0049] In the above embodiment, wastewater containing oxygenated compounds first enters the stripping unit, where a stripping operation is performed at a relatively high temperature. The volatile oxygenated compounds in the wastewater are stripped to form crude steam, while the purified water is discharged from the bottom of the stripping unit. Subsequently, the crude steam is transported to a reflux tank for cooling and gas-liquid separation. The separated non-condensable gas is discharged from the top of the reflux tank. This non-condensable gas is introduced into the combustion unit, where it is thoroughly mixed with combustion air and incinerated at high temperature to generate high-temperature, harmless waste gas whose main components are carbon dioxide and water. Finally, this high-temperature, harmless waste gas enters the steam unit, where its contained heat energy is transferred to the boiler feedwater, thereby producing medium-pressure steam.

[0050] The core of this method is to guide the non-condensable gas separated from wastewater through stripping to an incineration unit for high-temperature combustion. This step fundamentally solves the persistent problem of oxygen-containing compounds circulating and accumulating within the olefin separation system. Through incineration, oxygen-containing compounds such as acetone and dimethyl ether in the non-condensable gas are completely oxidized and decomposed into harmless carbon dioxide and water, completely avoiding their impact on the quality of downstream products. Simultaneously, the waste heat generated by incineration is efficiently recovered and utilized in the steam unit to generate valuable medium-pressure steam, significantly improving the energy utilization efficiency and economic benefits of the entire process, achieving the dual goals of environmental protection and energy conservation.

[0051] Furthermore, the methods also include: 201. Wastewater is heated by the feed heat exchanger before entering the stripping tower; 202. The reboiler heats the stripping tower with low-pressure steam to obtain crude steam and purified water; 203. After being cooled by the stripper heat exchanger, the crude steam enters the reflux tank for separation, yielding reflux wastewater and non-condensable gas; 204. The reflux pump returns the reflux wastewater to the stripping tower; 205. Open the fuel gas valve, blower and incinerator, open the first incineration valve and the second incineration valve, and close the remelting valve and flare valve; 206. Adjust the pressure regulating valve to mix the non-condensable gas with the regenerated flue gas, and then input the mixed gas into the incinerator for combustion; 207. The high-temperature harmless waste gas generated by incineration is transported to the steam unit to generate medium-pressure steam.

[0052] In the above embodiments, the upstream wastewater first flows through the feed heat exchanger, where it is preheated using the waste heat from the purified water. The preheated wastewater then enters the upper part of the stripping tower. The reboiler uses external low-pressure steam to heat the bottom of the stripping tower, providing the heat energy required for stripping the wastewater and causing oxygen-containing compounds to vaporize and form crude steam that escapes from the top of the tower, while the purified water accumulates in the bottom. The crude steam at the top of the tower then enters the stripping gas heat exchanger for cooling, where most of the water vapor condenses. The cooled gas-liquid mixture enters the reflux tank for final separation. The separated non-condensable gas is located at the top of the tank, and the condensed reflux wastewater is pressurized by the reflux pump and sent back to the top of the stripping tower as reflux. When the incineration treatment mode is selected, the fuel gas valve is first opened to introduce fuel gas, and the blower is started to supply combustion air, igniting the incinerator to reach its operating temperature. After confirming that the incinerator is operating normally, the first and second incineration valves are opened to establish a non-condensable gas passage, while the reflux valve and flare valve are closed to cut off other pathways. The flow and pressure of non-condensable gas are controlled by adjusting the pressure regulating valve, ensuring thorough mixing with the high-temperature regenerated flue gas introduced through the regenerated flue gas pipeline at the incinerator inlet or within the furnace. The mixed gas undergoes a vigorous oxidation reaction in the high-temperature environment of the incinerator, completely decomposing the oxygen-containing compounds in the non-condensable gas. The high-temperature, harmless waste gas produced by incineration is then directed to the steam unit to heat the boiler feedwater and generate medium-pressure steam.

[0053] This detailed operating procedure ensures the high efficiency, safety, and reliability of the entire process. The preheating design utilizing a feed heat exchanger and purified water reflux significantly reduces energy consumption. The separation system, consisting of a stripping tower, reflux tank, and reflux pump, guarantees efficient removal of oxygenated compounds. The incineration stage employs step-by-step operation and dual-valve isolation to ensure safety. The key step lies in mixing and incinerating non-condensable gas with high-temperature regenerated flue gas: the regenerated flue gas not only provides some combustion air, but its higher temperature significantly increases the initial combustion temperature of the mixture, creating extremely favorable conditions for the complete decomposition of oxygenated compounds that are difficult to decompose in the non-condensable gas. This is the core guarantee for achieving complete removal of oxygenated compounds and preventing their accumulation. Simultaneously, the recovery of combustion waste heat further improves the process's economics. This integrated method effectively solves the technical problems of cyclic accumulation caused by remelting and the inability to completely treat flare emissions in the background technology, comprehensively improving product quality, energy efficiency, and environmental benefits.

[0054] This application provides a non-condensable gas treatment device, comprising: a stripping unit for separating wastewater to obtain crude steam and purified water; a reflux tank 5 connected to the stripping unit for separating crude steam to obtain reflux wastewater and non-condensable gas; a combustion unit connected to the reflux tank 5 for incinerating the non-condensable gas separated in the reflux tank 5 to obtain high-temperature harmless waste gas; and a steam unit connected to the combustion unit for generating medium-pressure steam from the high-temperature harmless waste gas.

[0055] This application introduces non-condensable gas from the wastewater stripping tower and regenerated flue gas into an incinerator for high-temperature combustion, completely decomposing oxygen-containing compounds such as acetone and dimethyl ether into harmless substances. This eliminates the defects caused by their accumulation in the olefin separation system, which leads to pollution of products such as propane and mixed C4. Furthermore, this application also transports the high-temperature harmless waste gas generated from incineration to a steam unit, utilizing its thermal energy to produce medium-pressure steam for grid connection. This transforms the pollutant treatment process into an energy recovery process, realizing resource utilization and ensuring the stable operation of the oxygen-containing compound elimination pathway and energy recovery process across the entire process scenario.

[0056] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing this application. Those skilled in the art will understand that the modules in the apparatus of the embodiment can be distributed within the apparatus of the embodiment as described, or can be modified to be located in one or more apparatuses different from this embodiment. The modules of the above-described embodiment can be combined into one module, or further divided into multiple sub-modules.

[0057] The serial numbers in this application are for descriptive purposes only and do not represent the superiority or inferiority of any particular implementation scenario. The above disclosures are merely a few specific implementation scenarios of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A non-condensable gas treatment device, characterized in that, include: A stripping unit, wherein the stripping unit is used to separate wastewater to obtain crude steam and purified water; The reflux tank (5) is connected to the stripping unit and is used to separate crude steam to obtain reflux wastewater and non-condensable gas; Combustion unit, which is connected to the return tank (5), is used to burn the non-condensable gas separated by the return tank (5) to obtain high-temperature harmless waste gas; A steam unit, connected to the combustion unit, is used to generate medium-pressure steam from high-temperature harmless waste gas.

2. The apparatus according to claim 1, characterized in that, The device further includes: Feed heat exchanger (1), which is connected to the stripping unit, is used to receive and heat wastewater; Purified water pump (3), which is connected to the stripping unit and the feed heat exchanger (1), is used to return the purified water separated by the stripping unit to the feed heat exchanger (1).

3. The apparatus according to claim 1, characterized in that, The device further includes: Pressure regulating valve (8) is provided on the connecting pipeline between the return tank (5) and the combustion unit.

4. The apparatus according to claim 2, characterized in that, The stripping unit includes: Stripping tower (2), which is connected to the feed heat exchanger (1) and the reflux tank (5), is used to strip crude steam and generate purified water in the tower bottom; A reboiler (7) is connected to the stripping tower (2) and is used to heat purified water; A stripper heat exchanger (4) is connected to the stripper tower (2) and the reflux tank (5) and is used to cool crude steam. A reflux pump (6) is installed on the connecting pipeline between the stripping tower (2) and the reflux tank (5) to send reflux wastewater back to the stripping tower.

5. The apparatus according to claim 1, characterized in that, The device further includes: Non-condensable gas sub-line (21), which connects the reflux tank (5) and the stripping unit, is used to adjust the pressure difference between the reflux tank (5) and the stripping tower (2); Sub-line valve (20), which is located on the non-condensable gas sub-line (21).

6. The apparatus according to claim 1, characterized in that, The combustion unit includes: Incinerator (15), which is connected to the reflux tank (5); Incineration pipeline (22), which connects the incinerator (15) and the reflux tank (5); The first combustion valve (13) and the second combustion valve (14) are located on the combustion pipeline (22) and are used to control the flow of non-condensable gas into the incinerator (15). A regenerated flue gas pipeline (23) is connected to the incinerator (15) and is used to introduce regenerated flue gas into the incinerator (15).

7. The apparatus according to claim 6, characterized in that, The combustion unit further includes: Flare line (10), which is connected to the reflux tank (5); Flame valve (9), the flame valve (9) is provided on the flame line (10); The remelting pipeline (12) is connected to the reflux tank (5); A remelting valve (11) is provided on the remelting pipeline (12); The flare line (10) is connected in parallel with the remelting line (12) and the incineration line (22).

8. The apparatus according to claim 6, characterized in that, The device further includes: Blower (18), which is connected to the incinerator (15) and is used to supply combustion air into the incinerator (15); An air valve (19) is provided on the input pipe of the blower (18); Fuel gas pipeline (17) is connected to the incinerator (15) and is used to ignite and start the incinerator (15). Fuel gas valve (16) is provided on the fuel gas pipeline (17).

9. A method for treating non-condensable gases, characterized in that, include: Wastewater is separated to obtain crude steam through a stripping unit; The crude steam is fed into a reflux tank for separation to obtain non-condensable gas; Non-condensable gas is transported to the combustion unit for incineration to obtain high-temperature harmless waste gas; High-temperature harmless waste gas is treated by a steam unit to obtain medium-pressure steam.

10. The method according to claim 9, characterized in that, The method further includes: Wastewater is heated by the feed heat exchanger before entering the stripping tower; The reboiler heats the stripping tower with low-pressure steam to obtain crude steam and purified water; After being cooled by a stripper heat exchanger, the crude steam enters a reflux tank for separation, yielding reflux wastewater and non-condensable gas. The return pump sends the returned wastewater back to the stripping tower; Turn on the fuel gas valve, blower and incinerator, open the first incineration valve and the second incineration valve, and close the remelting valve and flare valve; Adjust the pressure regulating valve to mix the non-condensable gas with the regenerated flue gas, and then input the mixed gas into the incinerator for combustion; The high-temperature, harmless waste gas generated by incineration is transported to the steam unit to generate medium-pressure steam.

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