Method for removing oxygen-containing compounds in reaction generated gas of butadiene prepared by oxidative dehydrogenation of butene

Abstract

The invention discloses a method for removing oxygen-containing compounds in a reaction generated gas for preparing butadiene through oxidative dehydrogenation of butylene. The method comprises the following steps: step S1, the generated gas enters a generated gas gas-liquid separation tank to be separated into a generated gas gas phase and a lower liquid phase; s2, a gas phase of the generated gas separated by the generated gas-liquid separation tank enters a quenching elution tower from a quenching section at the lower section to be in contact with washing water, tower kettle wastewater is extracted from a tower kettle of the quenching elution tower, most of the tower kettle wastewater flows back to the upper part of the quenching section of the quenching elution tower as the washing water, and the generated gas is extracted from the top of the quenching elution tower; s3, a small part of tower kettle wastewater enters a stripping tower for stripping, stripping purified water is extracted from the tower kettle of the stripping tower, and an oxygen-containing compound gas phase is extracted from the top of the stripping tower. According to the invention, the tower kettle wastewater of the quenching elution tower is sent into the stripping tower to be treated, so that the tower kettle wastewater of the quenching elution tower is prevented from being directly discharged, the wastewater amount can be reduced, and COD in the discharged wastewater is prevented from exceeding the standard.

Description

Technical Field

[0001] The invention belongs to the technical field of butene oxidative dehydrogenation to produce butadiene, and in particular relates to a method for removing oxygen-containing compounds from gas generated by the reaction of butene oxidative dehydrogenation to produce butadiene. Background Art

[0002] Butadiene is a core raw material for chemical products such as synthetic rubber, synthetic resin, nylon 66, adiponitrile, and 1,4-butanediol. The oxidative dehydrogenation of butene is a mainstream production route due to its high conversion rate and selectivity. However, this process has significant drawbacks: high levels of oxygenated organic compounds such as aldehydes and ketones (such as acetaldehyde and acetic acid) generated by side reactions, resulting in large volumes of wastewater and significant treatment challenges.

[0003] The primary reaction in butene oxidative dehydrogenation is the reaction of butene with oxygen to form butadiene and water. Side reactions include deep oxidation to CO2 and CO, as well as oxidative degradation to oxygenated organic compounds such as acetic acid, acetaldehyde, ketones, and alcohols. To separate oxygenated impurities from C4 hydrocarbons, a water scrubbing process is commonly used in industry. However, the introduction of large amounts of scrubbing water leads to a surge in total wastewater volume within the system, necessitating costly biochemical treatment.

[0004] The current mainstream industrial process utilizes a dual-tower purification system combining quenching, acid washing, and aldehyde washing. The detailed process is as follows: After waste heat recovery, the reaction products are separated into gas and liquid phases. The gas phase enters the quenching tower, where it is gradually cooled by multiple stages of circulating water and then injected with alkaline solution to neutralize and remove acetic acid. The liquid phase, after waste heat recovery, is mixed with the tower bottom water, partially recycled back to the quenching tower for reuse, while the remainder is directly sent for biochemical treatment. The gas overhead from the quenching tower is pressurized by a compressor and then enters the bottom of the aldehyde washing tower, where it comes into countercurrent contact with the wash water injected overhead, efficiently removing light oxygenates such as acetaldehyde. The purified gas enters the downstream oil absorption unit to purify the butadiene product. The aldehyde-containing wastewater at the bottom of the tower is then transferred to a stripping tower where acetaldehyde is removed by steam heating and stripping. The water at the bottom of the stripping tower is cooled and then recycled to the top of the aldehyde washing tower, creating a local water cycle to reduce fresh water consumption. Despite this, the system still faces issues such as low wastewater recycling efficiency and the risk of residual oxygenated organic matter. New water treatment technologies or process optimization solutions are urgently needed to improve both environmental and economic performance.

[0005] Patent CN103965005B discloses a deacidification process for the product gas from the oxidative dehydrogenation of butene. The process utilizes a split water-cooled tower with a water-cooled section at the bottom and a saturation section at the top. The product gas from the oxidative dehydrogenation of butene enters the bottom of the water-cooled section and countercurrently contacts wash water injected from the top of the tower to remove organic acids and some aldehyde-containing oxygenates. Water from the water-cooled section is then introduced into the saturation section, where it countercurrently contacts the feed air to strip acetic acid and acetaldehyde. The stripped air is then returned to the oxidative dehydrogenation reactor as feed. The overhead gas is compressed and transported to an aldehyde scrubber, where the wash water further removes residual aldehydes. This process has two core defects: first, oxygen-containing compounds (such as acetic acid and acetaldehyde) are circulated back to the reactor with the stripping air, which easily forms an enrichment effect in the system, induces an increase in side reactions, aggravates the carbon deposition and deactivation of the catalyst, and significantly reduces its service life; second, the water cooling system does not introduce alkaline solution to neutralize acidic substances, resulting in acidic wastewater. Stainless steel materials are required for pipes, valves, instruments and equipment that come into contact with the wastewater, which greatly increases the investment cost of the equipment.

[0006] Patent CN213357400 U discloses an apparatus for removing oxides from butene during the oxidative dehydrogenation of crude butadiene. The generated gas from the oxidative dehydrogenation reaction undergoes heat recovery and quenching in an acid washing tower. It then passes through a generated gas compressor and cooler before being directly fed into an oil absorption and desorption unit. The C4 components separated by the oil absorption and desorption unit enter an extraction tower from the bottom. Oxides such as acetaldehyde are removed via circulating water as an extractant. This process, which involves first washing with oil and then washing with water to remove aldehydes, exacerbates contamination of solvent oil with oxides, necessitating increased solvent oil regeneration frequency. Furthermore, some oxygenated compounds, such as acetaldehyde, are readily soluble in C6 oil and have a low boiling point. However, improper temperature control can lead to condensation reactions during the regeneration process (e.g., to form paraldehyde), resulting in less volatile products. Furthermore, the presence of the aldehyde washing tower increases the complexity of the apparatus and water consumption.

[0007] CN117732189A, CN104098212A and CN104418693B all disclose energy-saving methods for butadiene production from butene oxidative dehydrogenation product gas, and also describe the mainstream processes of butene oxidative dehydrogenation.

[0008] The main problems existing in the operation of the production device are:

[0009] (1) Due to the elution in the rapid cooling section and the internal circulation section of the acid washing tower, acid compounds and most of the acetaldehyde are eluted into the wastewater, and the wastewater in the acid washing tower is directly discharged into the downstream system, causing the COD of the discharged wastewater to seriously exceed the standard, thereby increasing the cost of downstream sewage treatment.

[0010] (2) In the conventional process, the generated gas from the top of the quenching tower is compressed and then enters the aldehyde washing tower to remove acetaldehyde. However, the generated gas from the top of the acid washing tower has a high acetaldehyde content. When entering the aldehyde washing tower, it is easy to cause the pipelines between the sections of the compressor to be blocked due to acetaldehyde condensation, affecting the long-term stable operation of the compressor.

[0011] (3) In actual operation, fresh water can be used in the quenching tower to reduce the oxygen-containing compounds in the generated gas. Although different methods are adopted in various patents, the use of fresh water cannot be eliminated.

[0012] (4) The increase in the amount of water used to wash the quenching acid tower not only requires a large amount of fresh water, but also causes the amount of wastewater discharged from the tower bottom to increase exponentially. The cost of wastewater treatment increases accordingly, which seriously affects the overall economic benefits of the butene oxidative dehydrogenation unit.

[0013] (5) In actual operation, the operating pressure of the stripping tower is relatively high, the reboiler of the stripping tower consumes a large amount of steam, and the energy consumption is high. Summary of the Invention

[0014] Aiming at the technical problem that the wastewater in the existing quenching tower is directly discharged downstream, resulting in seriously excessive COD in the discharged wastewater, the present invention aims to provide a method for removing oxygen-containing compounds from the generated gas of the reaction of butene oxidative dehydrogenation to butadiene.

[0015] The object of the present invention is to provide a method for removing oxygen-containing compounds from the gas generated by the oxidative dehydrogenation of butene to butadiene reaction, comprising the following steps:

[0016] Step S1, the generated gas enters the generated gas-liquid separation tank and is separated into a generated gas phase and a lower liquid phase;

[0017] In step S2, the generated gas after separation in the gas-liquid separator enters the quenching section in the lower section into the quenching elution tower to contact with washing water, and the quenching elution tower bottom produces the tower bottom waste water, most of which is refluxed to the upper part of the quenching section of the quenching elution tower as washing water, and the generated gas is produced from the top of the quenching elution tower;

[0018] In step S3, a small portion of the waste water from the bottom of the tower enters the stripping tower for stripping, the bottom of the stripping tower produces stripping purified water, and the top of the stripping tower produces the oxygen-containing compound gas phase.

[0019] Preferably, in step S3A, elution wastewater is extracted from the acetaldehyde-rich high-concentration liquid in the elution section of the upper section of the quenching elution tower, and after merging with a small part of the tower bottom wastewater, it enters the stripping tower for stripping together; preferably, the elution wastewater is first heat-exchanged with the secondary waste heat of the stripping purified water in the tower bottom of the stripping tower, and then merged with a small part of the tower bottom wastewater, and then heat-exchanged with the primary waste heat of the stripping purified water in the tower bottom of the stripping tower, and finally enters the stripping tower for stripping together, so as to improve the elution effect of the oxygen-containing compounds in the elution section.

[0020] Preferably, in step S2, the generated gas extracted from the top of the quench elution tower directly enters the downstream generated gas compression system.

[0021] Preferably, in step S3, the liquid phase of the oxygen-containing compound gas phase extracted from the top of the stripping tower is condensed and refluxed from the upper part of the stripping tower to the stripping tower for cyclic stripping, and the condensed gas phase of the oxygen-containing compound gas phase enters the downstream incineration system.

[0022] Preferably, in step S2,

[0023] The stripping purified water produced from the stripping tower kettle is circulated back to the elution section of the quenching elution tower as washing water. Preferably, a portion of the stripping purified water produced from the stripping tower kettle is circulated back to the elution section of the quenching elution tower as washing water, and the other portion of the stripping purified water is discharged to the biochemical treatment device;

[0024] Add alkali solution into the elution section of the quench elution tower;

[0025] The recycled water is sent from the upper part of the elution section into the quench elution tower as washing water.

[0026] Preferably, in step S2,

[0027] A portion of the stripping purified water extracted from the stripping tower kettle is mixed with alkali solution as washing water and then sent to the elution section of the quenching elution tower.

[0028] Preferably, the stripping purified water is divided into a first stripping purified water and a second stripping purified water;

[0029] The first stripping purified water is combined with the recycled water as washing water and then enters the upper part of the elution section of the quenching elution tower; the second stripping purified water is used as washing water and then enters the elution section of the quenching elution tower. Preferably, the second stripping purified water is combined with the alkali solution as washing water and then enters the elution section of the quenching elution tower.

[0030] Preferably, a portion of washing water is extracted from the elution section of the quench elution tower as enhanced elution circulating water, the second portion of the enhanced elution circulating water is combined with most of the tower bottom wastewater and refluxed to the upper portion of the quench section of the quench elution tower as washing water, and the first portion of the enhanced elution circulating water is mixed with the alkali solution and then enters the elution section of the quench elution tower;

[0031] Preferably, the first part of the enhanced elution circulating water, the alkali solution and the stripping purified water are mixed and then enter the elution section of the quench elution tower;

[0032] Or preferably, the stripping purified water is divided into a first stripping purified water and a second stripping purified water; the first stripping purified water is combined with the recycled water as washing water and enters the upper part of the elution section of the quenching elution tower; the second stripping purified water enters the elution section of the quenching elution tower as washing water, and the first part of the enhanced elution circulating water is mixed with the alkali solution and enters the elution section of the quenching elution tower as washing water, or the first part of the enhanced elution circulating water, the alkali solution and the second stripping purified water are mixed and enter the elution section of the quenching elution tower as washing water.

[0033] Preferably, the wastewater from the tank generating the gas-liquid separation tank is mixed into the wastewater from the tower bottom.

[0034] Preferably,

[0035] After the wastewater from the tower bottom is pressurized by the pump at the bottom of the quenching and eluting tower, most of the wastewater from the tower bottom is cooled by the cooler at the lower end of the quenching and eluting tower and then flows back to the upper part of the quenching section of the quenching and eluting tower;

[0036] And / or, the recycled water is fed from the upper part of the elution section into the quench elution tower after being pressurized by the recycled water delivery pump through the recycled water buffer tank and temperature-controlled by the cooler at the upper end of the quench elution tower;

[0037] And / or, the stripping purified water extracted from the bottom of the stripping tower is pressurized by the stripping tower bottom pump and then undergoes a primary waste heat exchange with a small portion of the bottom wastewater through a primary heat exchanger; preferably, the stripping purified water after the primary waste heat exchange is cooled by a stripping purified water cooler, and a portion of the stripping purified water is circulated back to the elution section of the quenching elution tower as washing water, and the other portion of the stripping purified water is discharged to a biochemical treatment device; or, a portion of the stripping purified water after the primary waste heat exchange is subjected to a secondary waste heat exchange with the elution wastewater through a secondary heat exchanger and then circulated back to the elution section of the quenching elution tower, and the other portion is cooled by a stripping purified water cooler and then discharged to a biochemical treatment device;

[0038] and / or, the materials in the stripping tower are heated by a stripping tower reboiler;

[0039] And / or, the oxygen-containing compound gas phase extracted from the stripping tower top is condensed by the stripping tower top cooler and then enters the stripping tower top gas-liquid separation tank, the condensed liquid phase is pressurized by the stripping tower top reflux pump from the upper part of the stripping tower and then refluxed into the stripping tower for cyclic stripping, and the condensed oxygen-containing compound gas phase enters the downstream incineration system;

[0040] and / or, the enhanced elution circulating water is pressurized by the enhanced elution circulating pump and is divided into a first portion of enhanced elution circulating water and a second portion of enhanced elution circulating water;

[0041] And / or, the elution wastewater is pressurized by the elution wastewater delivery pump of the quenching elution tower and then merged with a small portion of the tower bottom wastewater into the stripping tower for stripping.

[0042] Another object of the present invention is to provide a system for removing oxygenated compounds from the gas generated by the oxidative dehydrogenation of butene to butadiene reaction, comprising:

[0043] Generated gas-liquid separation tank;

[0044] A quenching and eluting tower, the quenching and eluting tower having a quenching section in the lower section and an elution section in the upper section, the quenching section of the quenching and eluting tower being in communication with the upper gas-phase generated gas of the generated gas-liquid separation tank, the tower bottom of the quenching and eluting tower being provided with a tower bottom wastewater outlet pipe, a tower bottom wastewater main path being provided between the tower bottom wastewater outlet pipe and the upper portion of the quenching section for recirculating most of the tower bottom wastewater to the upper portion of the quenching section, so as to quench the gas-phase generated gas and incidentally remove some oxygen-containing compounds;

[0045] A stripping tower is provided with a tower bottom wastewater branch for inputting a small portion of the tower bottom wastewater into the stripping tower between the tower bottom wastewater outlet pipe of the quenching and eluting tower and the inlet of the stripping tower, so as to strip a small portion of the wastewater discharged from the tower bottom of the quenching and eluting tower, thereby greatly reducing the content of oxygen-containing compounds in the discharged wastewater.

[0046] Preferably, the elution section of the quench elution tower is provided with an elution wastewater branch at the position of the acetaldehyde-rich high-concentration liquid, and the elution wastewater branch is merged with the tower bottom wastewater branch and then connected to the inlet of the stripping tower. Preferably, the elution wastewater branch is first heat-exchanged with the secondary waste heat of the stripping purified water in the tower bottom of the stripping tower, and then merged with the tower bottom wastewater branch, and then heat-exchanged with the primary waste heat of the stripping purified water in the tower bottom of the stripping tower, and finally connected to the inlet of the stripping tower to collect the acetaldehyde-rich high-concentration wastewater in the elution section for stripping to improve the elution effect of oxygen-containing compounds in the elution section.

[0047] Preferably, the top of the quench elution tower is directly connected to a downstream product gas compression system.

[0048] Preferably, the top of the stripping tower is connected to a stripping tower top gas-liquid separation tank, all the liquid phase in the stripping tower top gas-liquid separation tank is refluxed to the upper part of the stripping tower, and the gas phase in the stripping tower top gas-liquid separation tank enters the downstream incineration system. Preferably, a stripping tower top cooler for cooling the gas phase at the top of the stripping tower is also connected between the top of the stripping tower and the stripping tower top gas-liquid separation tank.

[0049] Preferably, a stripping purified water circulation loop is provided between the stripping tower kettle and the elution section of the quenching elution tower, for circulating the stripping purified water from the stripping tower kettle back to the elution section. Preferably, the stripping purified water circulation loop is further connected to a stripping purified water discharge branch for discharging a portion of the stripping purified water into a downstream biochemical treatment device.

[0050] The elution section of the quench elution tower is provided with an alkali solution inlet;

[0051] A recycled water pipeline is provided on the upper part of the elution section of the quench elution tower.

[0052] Preferably, the stripping purified water circulation loop is combined with the alkali solution inlet pipe and then connected to the elution section of the quenching elution tower.

[0053] Preferably, the rear section of the stripping purified water circulation loop is bifurcated to connect a first stripping purified water circulation branch and a second stripping purified water circulation branch;

[0054] The first branch of the stripping purified water circulation is connected to the upper part of the elution section of the quenching elution tower after being merged with the recycled water pipeline; the second branch of the stripping purified water circulation is connected to the elution section of the quenching elution tower. Preferably, the second branch of the stripping purified water circulation is connected to the elution section of the quenching elution tower after being merged with the alkali solution inlet pipe.

[0055] Preferably, the elution section of the quench elution tower is further provided with an enhanced elution circulation water circuit, the rear section of the enhanced elution circulation water circuit is bifurcated into an upper branch and a lower branch, the lower branch of the enhanced elution circulation water circuit is merged with the main channel of the tower bottom wastewater of the quenching section and then connected to the upper part of the quenching section; the upper branch of the enhanced elution circulation water circuit is merged with the alkali solution inlet pipe and then connected to the elution section of the quench elution tower;

[0056] Preferably, the upper branch of the enhanced elution circulation water circuit, the alkali solution inlet pipe and the stripping purified water circulation loop are combined and connected to the elution section of the quench elution tower;

[0057] Or preferably, the rear section of the stripping purified water circulation loop is bifurcated and connected to a first branch of the stripping purified water circulation and a second branch of the stripping purified water circulation; the first branch of the stripping purified water circulation is merged with the recycled water pipeline and connected to the upper part of the elution section of the quenching elution tower; the second branch of the stripping purified water circulation is connected to the elution section of the quenching elution tower, and the upper branch of the enhanced elution circulation water circuit is merged with the alkali solution inlet pipe and connected to the elution section of the quenching elution tower, or, the upper branch of the enhanced elution circulation water circuit, the alkali solution inlet pipe and the second branch of the stripping purified water circulation are merged and connected to the elution section of the quenching elution tower.

[0058] Preferably, the wastewater from the reactor of the generated gas-liquid separation tank is connected to the wastewater outlet pipe of the tower reactor.

[0059] Preferably, a cooler at the lower end of the quenching elution tower for cooling the tower bottom wastewater is provided on the main line of the tower bottom wastewater;

[0060] And / or, the recycled water pipeline is provided with a cooler at the upper end of a quench elution tower for cooling the recycled water and a recycled water delivery pump;

[0061] And / or, a primary heat exchanger is provided on the stripping purified water circulation loop for performing a primary waste heat exchange with the tower bottom wastewater branch; preferably, a stripping purified water cooler is provided on the stripping purified water circulation loop for cooling the stripping purified water after the primary waste heat exchange, or a secondary heat exchanger is provided on the stripping purified water circulation loop for performing a secondary waste heat exchange with the elution wastewater branch after the primary waste heat exchange, and a stripping purified water cooler is provided on the stripping purified water discharge branch for cooling the discharged stripping purified water;

[0062] And / or, the stripping tower kettle is provided with a stripping tower reboiler;

[0063] And / or, a quenching and eluting tower bottom pump is provided on the tower bottom wastewater pipeline, and a stripping tower bottom pump for pressurizing stripping purified water is provided at the bottom of the stripping tower,

[0064] And / or, the enhanced elution circulation waterway is provided with an enhanced elution circulation pump;

[0065] And / or, a stripping tower top reflux pump is provided at the bottom of the stripping tower top gas-liquid separation tank;

[0066] And / or, a quenching elution tower elution wastewater delivery pump is provided on the elution wastewater branch line.

[0067] The positive progress effect of the present invention is:

[0068] 1) In the present invention, the bottom wastewater of the quenching elution tower is sent to the stripping tower for treatment, thereby avoiding direct discharge of the bottom wastewater of the quenching elution tower, reducing the wastewater discharge amount and avoiding excessive COD in the discharged wastewater.

[0069] 2) The present invention reduces the need for an aldehyde washing tower, and acid washing and aldehyde washing are simultaneously completed in a quenching and eluting tower, thereby preventing the acetaldehyde-containing generated gas from the top of the quenching and eluting tower from condensing in the generated gas compressor system and causing blockage of the inter-stage pipeline, thereby reducing equipment costs and lowering investment expenses.

[0070] 3) In the present invention, part of the stripping purified water at the bottom of the stripping tower is recycled back to the quenching and eluting tower as washing water, which can greatly reduce the amount of fresh water used, reduce the wastewater output and the stripping energy consumption.

[0071] 4) For existing industrially operated devices, the system for removing oxygenated compounds from the reaction gas of butene oxidative dehydrogenation to butadiene according to the present invention can be used without requiring large-scale modification or additional investment or energy consumption.

[0072] 5) A single-stage enhanced circulation elution method is adopted in the elution section of the quench elution tower, which can increase the circulating water volume in the elution section to elute the oxides contained in the generated gas. Compared with the multi-stage enhanced circulation elution in the existing industrial technology, the process is simpler and the energy consumption is lower.

[0073] 6) In the elution section of the quenching elution tower, an elution wastewater branch is provided at the position of the acetaldehyde-rich high-concentration liquid. The extracted acetaldehyde-rich high-concentration liquid is sent to the stripping tower for stripping, which solves the problem of acetaldehyde accumulation inside the quenching elution tower, enhances the aldehyde washing effect, reduces the overall washing water load of the quenching elution tower, and reduces the energy consumption of the stripping tower.

[0074] 7) Add alkaline solution to the elution section of the quench elution tower to accelerate the removal of acidic substances in the generated gas.

[0075] 8) The top of the quench elution tower is supplemented with industrial circulating water and recycled water after wastewater treatment for washing, preferably recycled water after wastewater treatment.

[0076] 9) The top of the stripping tower adopts a full liquid reflux form. The gas phase at the top of the gas-liquid separation tank at the top of the stripping tower is sent to the downstream incineration system for treatment, and the liquid phase at the bottom of the gas-liquid separation tank at the top of the stripping tower is all returned to the top of the stripping tower, thereby avoiding the existing industrial equipment from discharging the liquid phase wastewater at the bottom of the gas-liquid separation tank at the top of the stripping tower, resulting in excessive COD of the wastewater and affecting subsequent treatment.

[0077] 10) The stripping tower is operated at low pressure, with an operating pressure of 0 to 0.2 MPag, preferably 0.03 to 0.1 MPag. The low operating pressure greatly reduces the steam consumption of the stripping tower reboiler and minimizes the energy consumption of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figures 1 to 4 is a process flow chart of the present invention;

[0079] Figure 5 The figure is a process flow chart of the prior art. DETAILED DESCRIPTION

[0080] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0081] Option 1:

[0082] like Figure 1As shown, the generated gas 1 after the oxidative dehydrogenation reaction of butene enters the generated gas gas-liquid separation tank V1 after cooling, and the tank top gas 2 is sent to the quenching section of the quenching and elution tower T1 to contact with the washing water in the tower to remove acid, acetaldehyde and other oxygen-containing compounds. The generated gas 16 from the top of the quenching and elution tower T1 after washing and removing the oxygen-containing compounds enters the downstream generated gas compression system. The wastewater 3 from the product gas-liquid separator V1 is mixed with the wastewater outlet pipe 4 from the tower bottom of the quenching and eluting tower T1 and pressurized by the tower bottom pump P2. The majority of the wastewater is cooled by the tower bottom cooler E2 from the tower bottom wastewater main line 5. It is then mixed with the enhanced elution circulating water from the lower branch 10 of the enhanced elution circulating water line 7 of the elution section of the quenching and eluting tower T1, which is pressurized by the enhanced elution circulating pump P1. The water is then returned to the upper part of the quenching section of the quenching and eluting tower T1. A small portion of the wastewater is then transferred from the tower bottom wastewater branch 17 to the stripping tower T2 after heat exchange with purified water through the primary heat exchanger E3. The enhanced elution circulating water from the enhanced elution circulating water line 7 is pressurized by the enhanced elution circulating pump P1 and then branched into the upper branch 8, which is mixed with alkali in the alkali inlet pipe 9. The enhanced elution circulating water is then circulated and enhanced to remove oxygenated compounds from the product gas within the tower. After passing through the recycled water buffer tank V2, the recycled water 12 is pumped by the recycled water delivery pump P4 and cooled by the cooler E1 at the top of the quenching elution tower. The purified water from stripping tower T2 is pressurized by the stripping tower bottom pump P3 in the purified water circulation loop 24 and then heat-exchanged with the bottom water from the bottom of quenching elution tower T1 in the primary heat exchanger E3. It is then cooled by the purified water cooler E4 and divided into two parts. One part returns to the top of quenching elution tower T1, where it is mixed with the enhanced elution circulating water from the upper branch 8 and the alkali solution from the alkali solution inlet 9 and then fed into quenching elution tower T1. The other part is discharged from the purified water discharge branch 25 to the downstream biochemical treatment device. The wastewater in the stripping tower T2 is heated and stripped by the stripping tower kettle reboiler E5. The oxygen-containing compound gas phase 19 extracted from the top of the stripping tower T2 is cooled by the stripping tower top cooler E6 and then enters the stripping tower top gas-liquid separation tank V3. The top gas phase 21 of the stripping tower top gas-liquid separation tank V3 goes to the downstream incineration system, and the bottom liquid phase 22 is pressurized by the stripping tower top reflux pump P5 and then returned to the upper part of the stripping tower T2.

[0083] Option 2:

[0084] like Figure 2As shown, the generated gas 1 after the oxidative dehydrogenation reaction of butene enters the generated gas gas-liquid separation tank V1 after cooling, and the tank top gas 2 is sent to the quenching section of the quenching and elution tower T1 to contact with the washing water in the tower to remove acid, acetaldehyde and other oxygen-containing compounds. The generated gas 16 from the top of the quenching and elution tower T1 after washing and removing the oxygen-containing compounds enters the downstream generated gas compression system. The wastewater 3 from the reactor of the product gas-liquid separator V1 is mixed with the wastewater from the bottom of the quenching and eluting tower at the outlet 4 and pressurized by the quenching and eluting tower bottom pump P2. The majority of the wastewater is cooled in the quenching and eluting tower bottom cooler E2 from the main reactor wastewater line 5. It is then mixed with the enhanced elution circulating water from the lower branch 10, which is pressurized by the enhanced elution circulating pump P1, in the elution section of quenching and eluting tower T1. The water then returns to the upper portion of the quenching section of quenching and eluting tower T1. A small portion of the wastewater is then transferred from the reactor wastewater branch 17 to the stripping tower T2 after heat exchange with purified water through the primary heat exchanger E3. The enhanced elution circulating water from the elution section of quenching and eluting tower T1 is drawn from the enhanced elution circulating water line 7, pressurized by the enhanced elution circulating pump P1, and then branched into the upper branch 8, which is mixed with alkali in the alkali inlet pipe 9 to circulate and enhance the elution of oxygenated compounds in the product gas. After passing through the recycled water buffer tank V2, the recycled water 12 is pumped by the recycled water delivery pump P4 and mixed with the stripping purified water 26. The water is then cooled in the upper cooler E1 of the quenching elution tower and delivered to the top of the elution section of the quenching elution tower T1. The stripping purified water from stripping tower T2 is pressurized in the purified water circulation loop 24 by the stripping tower bottom pump P3 and then heat-exchanged with the bottom water from the bottom of the quenching elution tower T1 in the primary heat exchanger E3. The water is then cooled in the stripping purified water cooler E4 and divided into two parts. One part 11 is returned to the upper section of the quenching elution tower T1 and delivered to the quenching elution tower T1. The other part 26 is mixed with the recycled water 14, cooled in the upper cooler E1 of the quenching elution tower, and then delivered to the top of the elution section of the quenching elution tower T1. The remaining part of the stripping purified water cooled in the stripping purified water cooler E4 is discharged from the stripping purified water discharge branch 25 to the downstream biochemical treatment device. The wastewater in the stripping tower T2 is heated and stripped by the stripping tower kettle reboiler E5. The oxygen-containing compound gas phase 19 extracted from the top of the stripping tower T2 is cooled by the stripping tower top cooler E6 and then enters the stripping tower top gas-liquid separation tank V3. The top gas phase 21 of the stripping tower top gas-liquid separation tank V3 goes to the downstream incineration system, and the bottom liquid phase 22 is pressurized by the stripping tower top reflux pump P5 and then returned to the upper part of the stripping tower T2.

[0085] Option 3:

[0086] like Figure 3As shown, the generated gas 1 after the oxidative dehydrogenation of butene is cooled and enters the generated gas separator V1. The overhead gas 2 is sent to the quenching section of the quenching and stripping tower T1, where it comes into contact with scrubbing water within the tower to remove acid, acetaldehyde, and other oxygen-containing compounds. The generated gas 16, after scrubbing and removing oxygen-containing compounds from the top of quenching and stripping tower T1, enters the downstream generated gas compression system. The kettle wastewater 3 from the quenching and stripping tower V1 is mixed with the quenching and stripping tower bottom wastewater outlet pipe 4 and pressurized by the quenching and acid washing tower bottom pump P2. The majority of the kettle wastewater flows from the kettle wastewater main line 5 through the quenching and stripping tower lower end cooler E2, then returns to the upper portion of the quenching section of the quenching and stripping tower T1. A small portion of the kettle wastewater flows from the kettle wastewater branch line 17, exchanges heat with purified stripping water through the primary heat exchanger E3, and is then sent to the stripping tower T2. After passing through the recycled water buffer tank V2, the recycled water 12 is pumped by the recycled water delivery pump P4, cooled by the top cooler E1 of the quenching elution tower, and then delivered to the top of the elution section of the quenching elution tower T1. The purified water after stripping in the stripping tower T2 is pressurized by the stripping tower bottom pump P3 in the purified water circulation loop 24 and then heat-exchanged with the bottom water from the bottom of the quenching elution tower T1 in the primary heat exchanger E3. It is then cooled in the stripping purified water cooler E4 and divided into two parts. One part is further divided into part 8, mixed with alkali solution from the alkali solution inlet 9, and then delivered to the elution section of the quenching elution tower T1. The other part 10 is mixed with recycled water 16, cooled by the top cooler E1 of the quenching elution tower, and then delivered to the top of the elution section of the quenching elution tower T1. The other part 25 of the purified water cooled by the stripping circulating water cooler E4 is discharged from the stripping purified water discharge branch 25 to the downstream biochemical treatment device. The wastewater in the stripping tower T2 is heated and stripped by the stripping tower kettle reboiler E5. The oxygen-containing compound gas phase 19 extracted from the top of the stripping tower T2 is cooled by the stripping tower top cooler E6 and then enters the stripping tower top gas-liquid separation tank V3. The top gas phase 21 of the stripping tower top gas-liquid separation tank V3 goes to the downstream incineration system, and the bottom liquid phase 22 is pressurized by the stripping tower top reflux pump P5 and then returned to the upper part of the stripping tower T2.

[0087] Option 4:

[0088] like Figure 4As shown, the generated gas 1 after the oxidative dehydrogenation reaction of butene enters the generated gas gas-liquid separation tank V1 after cooling, and the tank top gas 2 is sent to the quenching section of the quenching and elution tower T1 to contact with the washing water in the tower to remove acid, acetaldehyde and other oxygen-containing compounds. The generated gas 16 from the top of the quenching and elution tower T1 after washing and removing the oxygen-containing compounds enters the downstream generated gas compression system. The bottom waste water 3 of the generated gas-liquid separation tank V1 is mixed with the bottom waste water outlet pipe 4 of the quenching elution tower, and then pressurized by the bottom pump P2 of the quenching elution tower. Most of the bottom waste water is cooled from the bottom waste water main line 5 through the cooler E2 at the lower end of the quenching elution tower, and then returned to the upper part of the quenching section of the quenching elution tower T1; a small part of the bottom waste water is mixed from the bottom waste water branch line 17 with the acetaldehyde-rich high-concentration liquid 28 extracted from the elution waste water branch line 26 of the elution section of the quenching elution tower T1, and then is sent to the stripping tower T2 after a heat exchange in the primary heat exchanger E3. The elution section of quench elution tower T1 extracts acetaldehyde-rich concentrated liquid from elution wastewater branch 26. After being pressurized by quench elution tower elution wastewater transfer pump P1, it undergoes heat exchange with stripping purified water 29 in secondary heat exchanger E7. After that, it is mixed with the bottom wastewater branch 17 and then transferred to stripping tower T1 for stripping, thereby enhancing the aldehyde removal effect of the elution section of the quench elution tower. Recycled water 12 passes through recycled water buffer tank V2, is pumped by recycled water transfer pump P4, mixed with stripping purified water 10, cooled by quench elution tower top cooler E1, and then transferred to the top of quench acid washing tower T1. After stripping in stripping tower T2, the purified water is pressurized by stripping tower bottom pump P3 from stripping purified water circulation loop 24 and then undergoes a primary heat exchange with wastewater 17 from the bottom of quenching elution tower T1 in primary heat exchanger E3. The purified water is then divided into two parts. One part, purified water 29, undergoes secondary heat exchange with acetaldehyde-rich concentrated liquid 27 extracted from the elution section of quenching elution tower T1 in secondary heat exchanger E7. The water is then divided into two parts: one part 8, which is mixed with alkali in alkali inlet pipe 9 and fed into the elution section of quenching elution tower T1. The other part 10, which is mixed with recycled water 16, is cooled in quenching elution tower top cooler E1 and fed into the top of quenching elution tower T1. The remaining part 30, after the primary heat exchange, is cooled in stripping purified water cooler E4 and then discharged from the purified water discharge branch 25 to the downstream biochemical treatment device. The wastewater in the stripping tower T2 is heated and stripped by the stripping tower kettle reboiler E5. The oxygen-containing compound gas phase 19 extracted from the top of the stripping tower T2 is cooled by the stripping tower top cooler E6 and then enters the stripping tower top gas-liquid separation tank V3. The top gas phase 21 of the stripping tower top gas-liquid separation tank V3 goes to the downstream incineration system, and the bottom liquid phase 22 is pressurized by the stripping tower top reflux pump P5 and then returned to the upper part of the stripping tower T2.

[0089] Example 1:

[0090] A process for removing oxygen-containing compounds from the gas generated by oxidative dehydrogenation of butene, according to the first scheme Figure 1As shown, butene oxidative dehydrogenation product gas 1, at a temperature of 90°C and a pressure of 50 kPag, at a flow rate of 135 t / h, enters product gas gas-liquid separator V1. Tank overhead gas 2 enters quenching and stripping tower T1. Kettle wastewater 3 and tower bottom wastewater 4 are pressurized by quenching and stripping tower bottom pump P2. Kettle wastewater 5 (mostly) at a flow rate of 500 t / h is cooled in quenching and stripping tower bottom cooler E2. Kettle wastewater 6 then enters the upper portion of the quenching section of quenching and stripping tower T1, where it quenches the product gas and removes oxygenated impurities. Another portion of 213.8 t / h of kettle wastewater 17 (a small portion) is then combined with stripping purified water 24 for primary heat exchange in primary heat exchanger E3 before entering the top of stripping tower T2. The enhanced elution circulating water 7 drawn from the elution section of quench elution tower T1 is pressurized by the enhanced elution circulating pump P1 and then divided into two sections, which are then returned to the elution section of quench elution tower T1 to remove oxygenated compounds. The first section, 150 t / h of enhanced elution circulating water 8, is fed into the elution section of quench elution tower T1 along with alkali solution 9 to scrub the generated gas and remove acidic substances. The second section, 100 t / h of enhanced elution circulating water 10, is circulated back to the upper section of quench elution tower T1 along with the bottom wastewater 6. To ensure the removal of oxygenated compounds in the product gas 16 at the top of quench elution tower T1, a stream of recycled water 12 is added to the top of quench elution tower T1. This 15 t / h recycled water 12 passes through the recycled water buffer tank V2, is pressurized by the recycled water delivery pump P4, and is cooled to 5°C in the upper cooler E1 of the quench elution tower before entering the top of quench elution tower T1. Stripping tower T2 has 20 theoretical plates and a top pressure of 0.05 MPaG. The bottom of stripping tower T2 is heated by steam via stripping tower reboiler E5. The oxygenated compound gas phase 19 at the top of stripping tower T2 is cooled to 40°C via stripping tower overhead condenser E6. The condenser discharge 20 undergoes gas-liquid separation in stripping tower overhead gas-liquid separator V3. The acetaldehyde-rich gas phase 21 is delivered to the downstream incineration system, while the acetaldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by stripping tower overhead reflux pump P5 and then delivered to stripping tower T2 23. To mitigate acetaldehyde polymerization in the overhead condenser, a polymerization inhibitor is added at a rate of 0.4 kg / h to the condenser inlet line. The stripping purified water 24 of the stripping tower T2 is respectively heat exchanged with the tower bottom wastewater 17 through the primary heat exchanger E3 and cooled by the stripping purified water cooler E4. Then, the stripping purified water 11 with a flow rate of 100 t / h is mixed with the first part of the enhanced elution circulating water 8 of the quenching elution tower T1 and enters the elution section of the quenching elution tower T1. The remaining stripping purified water 25 with a flow rate of 97.9 t / h is sent as effluent wastewater to the downstream biochemical treatment device for biochemical treatment.

[0091] Example 2

[0092] A process for removing oxygen-containing compounds from the gas generated by oxidative dehydrogenation of butene, according to the second scheme Figure 2As shown, butene oxidative dehydrogenation product gas 1, at a temperature of 90°C and a pressure of 50 kPag, with a flow rate of 135 t / h, enters product gas gas-liquid separator V1. Tank overhead gas 2 enters quenching and stripping tower T1. After being pressurized by quenching and stripping tower bottom pump P2, 500 t / h of quenching and stripping tower bottom wastewater 5 (most of which is cooled by quenching and stripping tower bottom cooler E2) enters quenching and stripping tower T1 in its quenching section, rapidly cooling the product gas and stripping oxygen-containing impurities. Another portion of quenching and stripping tower T1 bottom wastewater 4, pressurized by quenching and stripping tower bottom pump P2, with a flow rate of 309 t / h of quenching and stripping tower wastewater 17, undergoes a primary heat exchange with stripping purified water 24 in primary heat exchanger E3 before entering the top of stripping tower T2. The enhanced elution circulating water 7 drawn from the elution section of quench elution tower T1 is pressurized by the enhanced elution circulating pump P1 and then divided into two sections, which are then returned to the elution section of quench elution tower T1 to remove oxygenated compounds. The first section of enhanced elution circulating water 8, with a flow rate of 200 t / h, is fed into the elution section of quench elution tower T1 along with alkali solution 9 to scrub the generated gas and remove acidic substances. The second section of enhanced elution circulating water 10, with a flow rate of 50 t / h, is circulated back to the upper section of the quench section of quench elution tower T1 along with the bottom wastewater 6. To ensure the quality of oxygenated compound removal in the product gas 16 at the top of quench elution tower T1, a stream of recycled water 12 is added to the top of quench elution tower T1. This recycled water 12, with a flow rate of 15 t / h, passes through the recycled water buffer tank V2, is pressurized by the recycled water delivery pump P4, and cooled to 10°C in the quench elution tower upper cooler E1 before entering the top of quench elution tower T1. Stripping tower T2 has 20 theoretical plates and a top pressure of 0.05 MPaG. The bottom of stripping tower T2 is heated by steam via stripping tower reboiler E5. The oxygenated compound gas phase 19 at the top of stripping tower T2 is cooled to 40°C via stripping tower overhead condenser E6. The condenser discharge 20 undergoes gas-liquid separation in stripping tower overhead separator V3. The acetaldehyde-rich gas phase 21 is fed to the downstream incineration system, while the acetaldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by stripping tower overhead reflux pump P5 and then fed into stripping tower T2. To mitigate acetaldehyde polymerization in the overhead condenser, a polymerization inhibitor is added at a rate of 0.4 kg / h to the condenser inlet line. After the purified stripping water 24 at the bottom of stripping tower T2 undergoes heat exchange with the bottom wastewater 17 in the primary heat exchanger E3 and is cooled in the purified stripping water cooler E4, the second purified stripping water 11, with a flow rate of 30 t / h, enters the elution section of the quench elution tower T1. The first purified stripping water 26, with a flow rate of 180 t / h, is mixed with pressurized recycled water 14 and cooled to 10°C in the upper cooler E1 of the quench elution tower before entering the top of the quench elution tower T1. The remaining purified stripping water 25, with a flow rate of 98 t / h, is discharged as wastewater and sent to the downstream biochemical treatment unit for biochemical treatment.

[0093] Example 3

[0094] A process for removing oxygen-containing compounds from the gas generated by oxidative dehydrogenation of butene, according to Scheme 3 Figure 3 As shown, butene oxidative dehydrogenation product gas 1, at a temperature of 90°C and a pressure of 50 kPag, with a flow rate of 135 t / h, enters product gas gas-liquid separator V1. Tank overhead gas 2 enters quenching and stripping tower T1. Kettle wastewater 3, along with quenching and stripping tower T1's bottom wastewater 4, is pressurized by quenching and stripping tower bottom pump P2. Most of the 500 t / h kettle wastewater 5, cooled by quenching and stripping tower bottom cooler E2, enters quenching and stripping tower T1 through its quenching section. This quenching and stripping of oxygen-containing impurities is accomplished by cooling the remaining 309 t / h of bottom wastewater 17. This 309 t / h portion of the bottom wastewater 4 is then heat-exchanged with stripping purified water 24 in primary heat exchanger E3 before entering the top of stripping tower T2. To ensure the removal of oxygenates from the top product gas 16 of quench elution tower T1, a stream of recycled water 12 is added to the top of quench elution tower T1. This 15 t / h recycled water 12 flows through a recycled water buffer tank V2, is pressurized by a recycled water transfer pump P4, and cooled to 10°C in a quench elution tower top cooler E1 before entering the top of quench elution tower T1. Stripping tower T2 has 20 theoretical plates and a top pressure of 0.05 MPaG. The bottom of stripping tower T2 is heated by steam in a stripping tower reboiler E5. The oxygenate gas phase 19 at the top of stripping tower T2 is cooled to 40°C in an overhead condenser E6. The condenser discharge 20 undergoes gas-liquid separation in a stripping tower overhead separator V3. The acetaldehyde-rich gas phase 21 is delivered to a downstream incineration system, while the acetaldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by an overhead reflux pump P5 and then delivered to stripping tower T2. To mitigate acetaldehyde polymerization in the overhead condenser, a polymerization inhibitor is added at a rate of 0.4 kg / h to the condenser inlet. The stripping purified water 24 from stripping tower T2 undergoes a primary heat exchange with bottom wastewater 17 in the primary heat exchanger E3 and is cooled in the stripping purified water cooler E4. Secondary stripping purified water 8, with a flow rate of 30 t / h, is then fed into the elution section of quench elution tower T1 along with alkali liquor 9. First stripping purified water 10, with a flow rate of 180 t / h, is mixed with pressurized recycled water 14 and cooled to 10°C in the quench elution tower top cooler E1 before entering the top of quench elution tower T1. The remaining 98 t / h of stripping purified water 25 is discharged as wastewater and sent to a downstream biochemical treatment unit for biochemical treatment.

[0095] Example 4

[0096] A process for removing oxygen-containing compounds from the gas generated by oxidative dehydrogenation of butene, according to Scheme 4 Figure 4As shown, butene oxidative dehydrogenation product gas 1, at a temperature of 90°C and a pressure of 50 kPag, at a flow rate of 135 t / h, enters product gas gas-liquid separator V1. Tank overhead gas 2 enters quenching and stripping tower T1. Kettle wastewater 3, along with quenching and stripping tower T1's bottom wastewater 4, is pressurized by quenching and stripping tower bottom pump P2. Most of the 500 t / h kettle wastewater 5, cooled by quenching and stripping tower bottom cooler E2, enters quenching and stripping tower T1 in its quenching section. This quenching and stripping of oxygenated impurities is accomplished by cooling the remaining 309 t / h kettle wastewater 17. This is then combined with 10 t / h elution wastewater 28 drawn from the elution section of quenching and stripping tower T1, passing through a primary heat exchanger E3 and undergoing a heat exchange with stripping purified water 24 before entering the top of stripping tower T2. Wastewater 26 extracted from the elution section of quench elution tower T1 is pressurized by wastewater transfer pump P1 and then exchanged with the secondary waste heat of stripping purified water 29 in secondary heat exchanger E7. It is then mixed with wastewater 17 from the bottom of quench elution tower T1 and passed through primary heat exchanger E3 for heat exchange with the primary waste heat of stripping purified water 24 before entering stripping tower T2. Stripping tower T2 has 20 theoretical plates and a top pressure of 0.05 MPaG. The bottom of stripping tower T2 is heated by steam in stripping tower reboiler E5. The oxygenated gas phase 19 at the top of stripping tower T2 is cooled to 40°C via the stripping tower overhead condenser E6. The condenser discharge 20 undergoes gas-liquid separation in the stripping tower overhead gas-liquid separator V3. The acetaldehyde-rich gas phase 21 is sent to the downstream incineration system, while the acetaldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by the stripping tower overhead reflux pump P5 and then sent to stripping tower T2 23. To mitigate acetaldehyde polymerization in the overhead condenser, a polymerization inhibitor is added at a rate of 0.4 kg / h to the condenser inlet line. The purified water 24 from stripping tower T2 undergoes heat exchange with the bottom wastewater 17 in the primary heat exchanger E3 and is then split into two streams. One stream, purified water 29 at a flow rate of 30 t / h, exchanges heat with wastewater 27 drawn from the elution section of quenching and eluting tower T1 and pressurized by wastewater transfer pump P1 through the secondary heat exchanger E7. A portion of the second purified water 8 is mixed with alkali liquor 9 and enters the elution section of quenching and eluting tower T1. The other stream, purified water 10 at a flow rate of 180 t / h, is mixed with recycled water 12 from the outside at a flow rate of 15 t / h after being pressurized by the recycled water buffer tank V2 and recycled water transfer pump P4 14. The water is then cooled in the upper section of the quenching and eluting tower cooler E1 before entering the quenching and eluting tower T1. The remaining purified water 30 at a flow rate of 98 t / h is cooled in the purified water cooler E4 and then sent as wastewater to the downstream biochemical treatment unit for biochemical treatment 25.

[0097] Comparative Example

[0098] A process for removing oxygen-containing compounds from gas generated by oxidative dehydrogenation of butene, according to Figure 5As shown, butene oxidative dehydrogenation product gas 1, at a temperature of 90°C, a pressure of 50 kPag, and a flow rate of 135 t / h, enters product gas gas-liquid separator V1. Gas 2 from the top of the separator enters quenching and acid washing tower T1. Wastewater 3 from the bottom of the separator, along with wastewater 4 from the bottom of quenching and acid washing tower T1, is pressurized by quenching and acid washing tower bottom pump P3. A portion of the wastewater 5, with a flow rate of 800 t / h, is cooled by cooler E2 and then quenched at the lower end of quenching and acid washing tower T1 along with the product gas entering quenching and acid washing tower T1. The upper section of quenching and acid washing tower T1 undergoes two water washes to cool and remove oxygenated compounds. The upper section, circulating water 11, has a water flow rate of 217 t / h, including 200 t / h of circulating water 13 and 17 t / h of circulating water 14. The middle section, circulating water 7, has a water flow rate of 218 t / h, including 202 t / h of circulating water 8 and 16 t / h of circulating water 10. After the wastewater 4 at the bottom of the quenching acid wash tower T1 is pressurized by the quenching acid wash tower bottom pump P3, a portion of the wastewater 5 is returned to the quenching acid wash tower T1. A portion of the wastewater 17 is mixed with the condensate 25 separated in the gas-liquid separator V2 at the top of the stripping tower before being sent to biochemical treatment. The generated gas 16 from the top of the quenching acid wash tower T1 is pressurized to 1.35 MPa by compressor C1 and then sent to the aldehyde wash tower T3. The wash water used in the aldehyde wash tower T2 is the recycled wash water 30 after the stripping process, with a flow rate of 220 tons / hour. Fresh water 12 is added at a rate of 16 tons / hour. The generated gas 19 at the top of the aldehyde wash tower T2 is sent to the downstream oil washing unit. The wastewater 20 at the bottom of the aldehyde wash tower T2 is heat exchanged in the primary heat exchanger E3 before being sent to the stripping tower T2. To mitigate acetaldehyde polymerization in the overhead condenser, a polymerization inhibitor is added at a rate of 1 kg / h to the condenser inlet. Purified water 26 from the bottom of stripping tower T3 undergoes primary heat exchange in heat exchanger E3 and cooling in cooler E4 before entering the top of aldehyde scrubbing tower T2. Stripping tower T3 has 20 theoretical plates and a top pressure of 0.3 MPagg. The bottom reboiler E5 is heated with steam. The overhead gas 22 from stripping tower T3 is cooled to 40°C in overhead condenser E6. The condenser discharge 23 undergoes gas-liquid separation in overhead tank V2. Acetaldehyde-rich gas 24 is discharged from the delimited area, and the aldehyde-containing condensate 25 at the bottom of the tank is mixed with the wastewater 17 from the bottom of the quenched acid scrubbing tower and then sent to a biochemical treatment unit.

[0099] Table 1 Comparison of the results of Examples 1 to 4 and the comparative example

[0100]

[0101]

[0102] In summary, the present invention sends the wastewater from the bottom of the quenching elution tower T1 into the stripping tower T2 for treatment, and the COD value in the discharged wastewater is significantly lower than that in the comparative example, and thus the present invention can solve the problem of excessive COD in wastewater. At the same time, the present invention reduces the use of the aldehyde washing tower, avoids the problem of acetaldehyde condensation in the compressor system caused by the generated gas with high acetaldehyde concentration coming out of the quenching tower, and the acetaldehyde concentration in the generated gas after washing is not significantly improved compared with the comparative example, which simplifies the process flow and reduces the equipment cost. Moreover, the low operating pressure makes the steam consumption of the present invention significantly lower than that in the comparative example, greatly reduces the steam consumption of the stripping tower reboiler, and reduces the stripping energy consumption. And by sending the stripping purified water part of the bottom of the stripping tower T1 into the elution section of the quenching elution tower T1 as washing water, the fresh water consumption is greatly reduced, the wastewater output is reduced, and the investment cost is reduced.

[0103] The present invention has been described in detail above with reference to the embodiments of the accompanying drawings. A person skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the scope defined by the appended claims.

Claims

1. A method for removing oxygen-containing compounds from the gas generated by the oxidative dehydrogenation of butene to butadiene, characterized in that The steps include: Step S1, the generated gas enters the generated gas-liquid separation tank and is separated into a generated gas phase and a lower liquid phase; Step S2: The gas phase of the generated gas separated in the generated gas-liquid separator enters the quenching section in the lower section into the quenching elution tower to contact with washing water, and the quenching elution tower bottom produces the tower bottom waste water, most of which is refluxed to the upper part of the quenching section of the quenching elution tower as washing water, and the generated gas is produced from the top of the quenching elution tower; In step S3, a small portion of the waste water from the bottom of the tower enters the stripping tower for stripping, the bottom of the stripping tower produces stripping purified water, and the top of the stripping tower produces the oxygen-containing compound gas phase.

2. The method according to claim 1, wherein The method further comprises: Step S3A, extracting elution wastewater from the acetaldehyde-rich high-concentration liquid in the elution section of the upper section of the quenching elution tower, merging it with a small portion of the tower bottom wastewater, and then entering the stripping tower for stripping; preferably, the elution wastewater is first heat-exchanged with the secondary waste heat of the stripping purified water in the tower bottom of the stripping tower, and then merged with the small portion of the tower bottom wastewater, and then heat-exchanged with the primary waste heat of the stripping purified water in the tower bottom of the stripping tower, and finally entering the stripping tower for stripping.

3. The method according to claim 1, wherein In step S2, the generated gas extracted from the top of the quenching and elution tower directly enters the downstream generated gas compression system.

4. The method according to claim 1, wherein In step S3, the liquid phase of the oxygen-containing compound gas phase extracted from the top of the stripping tower is condensed and all flows back to the stripping tower from the top of the stripping tower for cyclic stripping, and the condensed gas phase of the oxygen-containing compound gas phase enters the downstream incineration system.

5. The method according to claim 1, wherein In step S2, The stripping purified water produced from the stripping tower kettle is circulated back to the elution section of the quenching elution tower as washing water. Preferably, a portion of the stripping purified water produced from the stripping tower kettle is circulated back to the elution section of the quenching elution tower as washing water, and the other portion of the stripping purified water is discharged to the biochemical treatment device; Add alkali solution into the elution section of the quench elution tower; The recycled water is sent from the upper part of the elution section into the quench elution tower as washing water.

6. The method according to claim 5, wherein In step S2, A portion of the stripping purified water extracted from the stripping tower kettle is mixed with alkali solution as washing water and then sent to the elution section of the quenching elution tower.

7. The method according to claim 5, wherein The stripping purified water is divided into a first stripping purified water and a second stripping purified water; The first stripping purified water is combined with the recycled water as washing water and then enters the upper part of the elution section of the quenching elution tower; the second stripping purified water is used as washing water and then enters the elution section of the quenching elution tower. Preferably, the second stripping purified water is combined with the alkali solution as washing water and then enters the elution section of the quenching elution tower.

8. The method according to claim 5, wherein The elution section of the quench elution tower also extracts a portion of washing water as enhanced elution circulating water, and the second portion of the enhanced elution circulating water is combined with most of the tower bottom wastewater and refluxed to the upper part of the quench section of the quench elution tower as washing water. The first portion of the enhanced elution circulating water is mixed with the alkali solution and then enters the elution section of the quench elution tower; Preferably, the first part of the enhanced elution circulating water, the alkali solution and the stripping purified water are mixed and then enter the elution section of the quench elution tower; Or preferably, the stripping purified water is divided into a first stripping purified water and a second stripping purified water; the first stripping purified water is combined with the recycled water as washing water and enters the upper part of the elution section of the quenching elution tower; the second stripping purified water enters the elution section of the quenching elution tower as washing water, the first part of the enhanced elution circulating water is mixed with the alkali solution and enters the elution section of the quenching elution tower as washing water, or the first part of the enhanced elution circulating water, the alkali solution and the second stripping purified water are mixed and enter the elution section of the quenching elution tower as washing water.

9. The method according to claim 1, wherein The wastewater from the gas-liquid separation tank is mixed into the wastewater from the tower bottom.

10. The method according to any one of claims 2 to 8, wherein: After the wastewater from the tower bottom is pressurized by the pump at the bottom of the quenching and eluting tower, most of the wastewater from the tower bottom is cooled by the cooler at the lower end of the quenching and eluting tower and then flows back to the upper part of the quenching section of the quenching and eluting tower; And / or, the recycled water is fed from the upper part of the elution section into the quench elution tower after being pressurized by the recycled water delivery pump through the recycled water buffer tank and temperature-controlled by the cooler at the upper end of the quench elution tower; And / or, the stripping purified water extracted from the bottom of the stripping tower is pressurized by the stripping tower bottom pump and then undergoes a primary waste heat exchange with a small portion of the bottom wastewater through a primary heat exchanger; preferably, the stripping purified water after the primary waste heat exchange is cooled by a stripping purified water cooler, and a portion of the stripping purified water is circulated back to the elution section of the quenching elution tower as washing water, and the other portion of the stripping purified water is discharged to a biochemical treatment device; or, a portion of the stripping purified water after the primary waste heat exchange is subjected to a secondary waste heat exchange with the elution wastewater through a secondary heat exchanger and then circulated back to the elution section of the quenching elution tower, and the other portion is cooled by a stripping purified water cooler and then discharged to a biochemical treatment device; and / or, the materials in the stripping tower are heated by a stripping tower reboiler; And / or, the oxygen-containing compound gas phase extracted from the stripping tower top is condensed by the stripping tower top cooler and then enters the stripping tower top gas-liquid separation tank, the condensed liquid phase is pressurized by the stripping tower top reflux pump from the upper part of the stripping tower and then refluxed into the stripping tower for cyclic stripping, and the condensed oxygen-containing compound gas phase enters the downstream incineration system; and / or, the enhanced elution circulating water is pressurized by the enhanced elution circulating pump and is divided into a first portion of enhanced elution circulating water and a second portion of enhanced elution circulating water; And / or, the elution wastewater is pressurized by the elution wastewater delivery pump of the quenching elution tower and then merged with a small portion of the tower bottom wastewater into the stripping tower for stripping.

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