A system for removing oxygen-containing compounds from the butene oxidative dehydrogenation reaction to butadiene.

Abstract

This utility model discloses a system for removing oxygen-containing compounds from the product gas of butene oxidative dehydrogenation to butadiene production, comprising: a product gas-liquid separator; a quenching and washing tower having a lower quenching section and an upper washing section, the quenching section of the quenching and washing tower being connected to the upper gas phase of the product gas-liquid separator, the bottom of the quenching and washing tower being provided with a bottom wastewater outlet pipe, the bottom wastewater outlet pipe being connected to the upper part of the quenching section via a main bottom wastewater channel that returns most of the bottom wastewater to the upper part of the quenching section; and a stripping tower, the bottom wastewater outlet pipe of the quenching and washing tower being connected to the inlet of the stripping tower via a branch channel that inputs a small portion of the bottom wastewater into the stripping tower. In this utility model, the bottom wastewater from the quenching and washing tower is sent to the stripping tower for treatment, avoiding direct discharge of the bottom wastewater from the quenching and washing tower, thus reducing wastewater volume and preventing excessive COD in the discharged wastewater.

Description

Technical Field

[0001] This utility model belongs to the field of butene oxidative dehydrogenation to butadiene production technology, and in particular relates to a system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation to butadiene production reaction. Background Technology

[0002] Butadiene is a core raw material for chemical products such as synthetic rubber, synthetic resin, nylon 66, adiponitrile, and 1,4-butanediol. The butene oxidative dehydrogenation process is one of the mainstream production routes due to its high conversion rate and selectivity. However, this process has significant drawbacks: the content of oxygen-containing organic compounds such as aldehydes and ketones (e.g., acetaldehyde, acetic acid) generated by side reactions is high, resulting in large volumes of wastewater that are difficult to treat.

[0003] The main reaction of butene oxidative dehydrogenation is the reaction of butene with oxygen to produce butadiene and water. Side reactions include deep oxidation to produce CO2 and CO, and oxidative degradation to produce oxygen-containing organic compounds such as acetic acid, acetaldehyde, ketones, and alcohols. To separate oxygen-containing impurities from C4 hydrocarbons, industrial processes commonly employ water washing. However, the introduction of large amounts of washing water leads to a surge in the total wastewater volume within the system, requiring subsequent high-cost biological treatment.

[0004] The current mainstream industrial process employs a dual-tower purification system of "quench cooling and acid washing + aldehyde washing." The specific process is as follows: After waste heat recovery, the reaction products separate into gas and liquid phases. The gas phase enters the quench tower, where it is cooled stage by staged circulating water and neutralized with alkali solution to remove acetic acid. The liquid phase, after waste heat recovery, mixes with the bottom water; part of it is recycled back to the quench tower for reuse, while the remainder is directly sent for biochemical treatment. The gas from the top of the quench tower is pressurized by a compressor and enters the bottom of the aldehyde washing tower, where it comes into countercurrent contact with the washing water injected from the top, efficiently removing acetaldehyde and other light oxygen-containing compounds. The purified gas enters the downstream oil absorption unit to purify butadiene products, while the aldehyde-containing wastewater from the bottom of the tower is sent to a stripping tower, where acetaldehyde is separated by steam heating and stripping. The bottom water of the stripping tower is cooled and reused at the top of the aldehyde washing tower, forming a local water circulation to reduce fresh water consumption. Despite this, the system still suffers from low wastewater circulation efficiency and the risk of residual oxygen-containing organic matter, necessitating the development of new water treatment technologies or process optimization schemes to improve environmental friendliness and economic efficiency.

[0005] Patent CN103965005B discloses a deacidification process for butene oxidative dehydrogenation product gas: a split-type water-cooled tower is used, with a water-cooled section at the bottom and a saturated section at the top. The butene oxidative dehydrogenation product gas enters from the bottom of the water-cooled section and comes into countercurrent contact with the washing water injected at the top of the tower, removing organic acids and some aldehyde oxygen-containing compounds. Subsequently, the water effluent from the water-cooled section is introduced into the saturated section, where it comes into countercurrent contact with the raw material air to strip acetic acid and acetaldehyde. The stripped air is then returned to the oxidative dehydrogenation reactor as raw material. The gas at the top of the tower is compressed and then transported to the aldehyde washing tower, where residual aldehydes are further removed by washing water. This process has two major flaws: First, oxygen-containing compounds (such as acetic acid and acetaldehyde) are recycled back to the reactor with the stripping air, which easily leads to an enrichment effect in the system, inducing more side reactions, aggravating catalyst carbon buildup and deactivation, and significantly reducing service life; Second, the water cooling system does not introduce alkaline solution to neutralize acidic substances, resulting in acidic wastewater. This requires the use of stainless steel for pipes, valves, instruments and equipment that come into contact with wastewater, which significantly increases the investment cost of the equipment.

[0006] Patent CN213357400 U discloses an oxide removal device for the production of crude butadiene from butene oxidative dehydrogenation. The gas generated from the oxidative dehydrogenation reaction, after heat recovery and quenching in an acid washing tower, is cooled by a gas compressor and cooler before directly entering an oil absorption and desorption unit. The C4 component separated in the oil absorption and desorption unit enters an extraction tower from the bottom; acetaldehyde and other oxides are removed by circulating water as the extractant. This process, involving oil washing followed by water washing for aldehyde removal, exacerbates oxide contamination of the solvent oil, requiring more frequent solvent oil regeneration. Furthermore, some oxygen-containing compounds, such as acetaldehyde, are readily soluble in C6 oil and have low boiling points, but during regeneration, improper temperature control may lead to condensation reactions (such as the formation of metaldehyde), resulting in more difficult-to-volatile products. Additionally, the presence of the aldehyde washing tower increases the complexity of the device 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 process of butene oxidative dehydrogenation.

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

[0009] (1) Due to the rinsing of the quenching section and the internal circulation section in the acid washing tower, acid compounds and most of the acetaldehyde are washed into the wastewater. The wastewater in the acid washing tower is directly discharged into the downstream system, resulting in the COD of the discharged wastewater seriously exceeding the standard, which increases the cost of downstream sewage treatment.

[0010] (2) In the conventional process, the generated gas from the top of the quench 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. During the process of entering the aldehyde washing tower, it is easy to cause blockage of the pipeline between the raw press sections due to acetaldehyde condensation, which affects the long-term stable operation of the raw press.

[0011] (3) In actual operation, fresh water can be used in the quench 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 increased washing water volume of the quenching acid washing tower not only requires a large amount of fresh water, but also causes the amount of wastewater discharged from the tower bottom to increase several times, and the wastewater treatment cost increases accordingly, which seriously affects the overall economic benefits of the butene oxidation 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 lot of steam and has high energy consumption. Utility Model Content

[0014] To address the technical problem of wastewater being directly discharged downstream from existing quench towers, resulting in severe COD exceedances in the discharged wastewater, the purpose of this utility model is to provide a novel system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation reaction to butadiene.

[0015] The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation reaction to butadiene production of this utility model includes:

[0016] Generative gas-liquid separator;

[0017] A quenching and elution tower has a quenching section in the lower part and an elution section in the upper part. The quenching section of the quenching and elution tower is connected to the upper gas phase of the generated gas in the generated gas-liquid separator. The bottom of the quenching and elution tower is provided with a bottom wastewater outlet pipe. The bottom wastewater outlet pipe is connected to the upper part of the quenching section to return most of the bottom wastewater to the main bottom wastewater channel in the upper part of the quenching section, so as to quench the gas phase generated gas and remove some oxygen-containing compounds in the process.

[0018] The stripping tower has a branch line between the bottom wastewater outlet of the quench washing tower and the inlet of the stripping tower, which inputs a small portion of the bottom wastewater into the bottom wastewater branch of the stripping tower to strip a small portion of the wastewater discharged from the bottom of the quench washing tower, thereby greatly reducing the oxygen content in the discharged wastewater.

[0019] Preferably, the elution section of the quenching elution tower has an elution wastewater branch at the location of the high-concentration acetaldehyde-rich liquid. The elution wastewater branch is merged with the bottom wastewater branch and then connected to the inlet of the stripping tower. Preferably, the elution wastewater branch first exchanges heat with the secondary waste heat of the stripping purified water in the bottom of the stripping tower, then merges with the bottom wastewater branch, then exchanges heat with the primary waste heat of the stripping purified water in the bottom of the stripping tower, and finally connects to the inlet of the stripping tower, so as to collect the high-concentration acetaldehyde-rich wastewater in the elution section for stripping to improve the elution effect of oxygen-containing compounds in the elution section.

[0020] Preferably, the top of the quench scrubbing tower is directly connected to the downstream generator gas compression system.

[0021] Preferably, the top of the stripping tower is connected to a stripping tower top gas-liquid separator, and the liquid phase in the stripping tower top gas-liquid separator is completely returned to the upper part of the stripping tower, while the gas phase in the stripping tower top gas-liquid separator enters the downstream incineration system. Preferably, a stripping tower top cooler for cooling the stripping tower top gas phase is also connected between the top of the stripping tower and the stripping tower top gas-liquid separator.

[0022] Preferably, there is a stripping purified water circulation loop between the stripping tower bottom and the elution section of the quenching elution tower, in which the stripping purified water from the stripping tower bottom is circulated back to the elution section. Preferably, the stripping purified water circulation loop is also connected to a stripping purified water discharge branch that discharges a portion of the stripping purified water into the downstream biochemical treatment device.

[0023] An alkaline solution inlet pipe is provided on the elution section of the quenching and elution tower;

[0024] A return water pipeline is installed at the upper part of the elution section of the quenching elution tower.

[0025] Preferably, the stripping purification water circulation loop is combined with the alkali inlet pipe and then connected to the elution section of the quenching and elution tower.

[0026] Preferably, the latter part of the stripping purified water circulation loop is branched and connected to a first branch of stripping purified water circulation and a second branch of stripping purified water circulation.

[0027] The first branch of the stripping purified water circulation and the recycled water pipeline are combined and connected to the upper part of the elution section of the quenching and elution tower; the second branch of the stripping purified water circulation is connected to the elution section of the quenching and elution tower. Preferably, the second branch of the stripping purified water circulation and the alkali inlet pipe are combined and connected to the elution section of the quenching and elution tower.

[0028] Preferably, the elution section of the quenching elution tower is further provided with an enhanced elution circulating water path. The latter part of the enhanced elution circulating water path branches into an upper branch and a lower branch. The lower branch of the enhanced elution circulating water path is connected to the upper part of the quenching section after merging with the main wastewater path of the quenching section. The upper branch of the enhanced elution circulating water path is connected to the alkali inlet pipe after merging with the elution section of the quenching elution tower.

[0029] Preferably, the upper branch of the enhanced elution circulating water circuit, the alkali inlet pipe, and the stripping purification water circulation circuit are combined and connected to the elution section of the quenching elution tower.

[0030] Preferably, the latter part of the stripping purified water circulation loop branches into a first branch and a second branch; the first branch merges with the recycled water pipeline and connects to the upper part of the elution section of the quenching and stripping tower; the second branch connects to the elution section of the quenching and stripping tower; the upper branch of the enhanced elution circulation water path merges with the alkali inlet pipe and connects to the elution section of the quenching and stripping tower; or, the upper branch of the enhanced elution circulation water path, the alkali inlet pipe, and the second branch of the stripping purified water circulation loop merge and connect to the elution section of the quenching and stripping tower.

[0031] Preferably, the wastewater from the bottom of the gas-liquid separator is connected to the wastewater outlet pipe of the tower bottom.

[0032] Preferably, a quenching and washing tower lower cooler for cooling the wastewater in the main pipeline of the tower bottom is provided;

[0033] And / or, the recycled water pipeline is equipped with a quenching stripper at the top of the cooling water stripper and a recycled water delivery pump;

[0034] And / or, the stripping purified water circulation loop is provided with a primary heat exchanger that performs a primary waste heat exchange with the column bottom wastewater branch; preferably, the stripping purified water circulation loop is provided with a stripping purified water cooler for cooling the stripping purified water after the primary waste heat exchange, or, the stripping purified water circulation loop is provided with a secondary heat exchanger that performs a secondary waste heat exchange with the stripping purified water branch after the primary waste heat exchange, and the stripping purified water discharge branch is provided with a stripping purified water cooler for cooling the discharged stripping purified water.

[0035] And / or, the stripping tower reboiler is provided with a stripping tower reboiler;

[0036] And / or, the wastewater pipeline of the tower bottom is equipped with a quenching washing tower bottom pump, and the bottom of the stripping tower is equipped with a stripping purified water pressurization stripping tower bottom pump.

[0037] And / or, the enhanced elution circulation water circuit is equipped with an enhanced elution circulation pump;

[0038] And / or, the bottom of the stripping tower top gas-liquid separator has a stripping tower top reflux pump;

[0039] And / or, the elution wastewater branch is equipped with a quench elution tower elution wastewater transfer pump.

[0040] Another objective of this invention is to provide a method for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation reaction to butadiene, comprising the following steps:

[0041] Step S1: The generated gas enters the generated gas-liquid separator and is separated into a generated gas phase and a lower liquid phase;

[0042] In step S2, the generated gas phase after separation in the gas-liquid separator enters the quenching and washing tower from the lower quenching section and comes into contact with the washing water. The bottom wastewater of the quenching and washing tower is collected, and most of the bottom wastewater is returned to the upper part of the quenching section of the quenching and washing tower as washing water. The generated gas is collected from the top of the quenching and washing tower.

[0043] In step S3, a small portion of the wastewater from the bottom of the stripper enters the stripper for stripping. Stripped purified water is collected from the bottom of the stripper, and oxygen-containing gas phase is collected from the top of the stripper.

[0044] Preferably, in step S3A, the elution wastewater, rich in acetaldehyde and collected from the elution section at the top of the quenching elution tower, is combined with a small portion of the tower bottom wastewater and then enters the stripping tower for stripping. More preferably, the elution wastewater first exchanges heat with the secondary waste heat of the stripping purified water in the tower bottom, then combines with a small portion of the tower bottom wastewater, and then exchanges heat again with the primary waste heat of the stripping purified water in the tower bottom before finally entering the stripping tower for stripping, thereby improving the elution effect of oxygen-containing compounds in the elution section.

[0045] Preferably, in step S2, the generated gas extracted from the top of the quench stripping tower directly enters the downstream generated gas compression system.

[0046] Preferably, in step S3, the oxygen-containing gas phase extracted from the top of the stripper is condensed and then the liquid phase is completely returned to the stripper from the top of the stripper for recycling and stripping, and the oxygen-containing gas phase is condensed and then enters the downstream incineration system.

[0047] Preferably, in step S2,

[0048] The stripping purified water collected from the bottom of the stripping tower is recycled back to the elution section of the quenching and elution tower as washing water. Preferably, a portion of the stripping purified water collected from the bottom of the stripping tower is recycled back to the elution section of the quenching and elution tower as washing water, while the other portion of the stripping purified water is discharged to the biochemical treatment device.

[0049] Alkali solution is added to the elution section of the quenching elution tower;

[0050] Reclaimed water is used as washing water and is fed into the quenching and washing tower from the top of the elution section.

[0051] Preferably, in step S2,

[0052] A portion of the stripping purified water collected from the bottom of the stripping tower is mixed with the alkali solution as washing water and then sent to the elution section of the quenching and elution tower.

[0053] Preferably, the stripping purified water is divided into first stripping purified water and second stripping purified water;

[0054] The first stripping purified water and the recycled water are combined as washing water and then enter the upper part of the elution section of the quenching and elution tower; the second stripping purified water is used as washing water and enters the elution section of the quenching and 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 and elution tower.

[0055] Preferably, the elution section of the quenching elution tower also extracts a portion of the washing water as enhanced elution circulating water. The second portion of enhanced elution circulating water is combined with most of the tower bottom wastewater and then returned to the upper part of the quenching section of the quenching elution tower as washing water. The first portion of enhanced elution circulating water is mixed with the alkali solution and then enters the elution section of the quenching elution tower.

[0056] Preferably, the first part of the enhanced elution circulating water, alkali solution and stripping purified water are mixed and then enter the elution section of the quenching elution tower;

[0057] Preferably, the stripping purified water is divided into first stripping purified water and second stripping purified water; the first stripping purified water and recycled water are combined as washing water and then enter the upper part of the elution section of the quenching and stripping tower; the second stripping purified water enters the elution section of the quenching and stripping tower as washing water; the first part of the enhanced elution circulating water is mixed with the alkali solution and then enters the elution section of the quenching and stripping 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 then enter the elution section of the quenching and stripping tower as washing water.

[0058] Preferably, the wastewater from the bottom of the gas-liquid separator is mixed with the wastewater from the bottom of the tower.

[0059] Better is,

[0060] After being pressurized by the bottom pump of the quenching and washing tower, most of the bottom wastewater is cooled by the cooler at the bottom of the quenching and washing tower and then flows back to the upper part of the quenching section of the quenching and washing tower.

[0061] And / or, the recycled water is pressurized by the recycled water transfer pump and temperature controlled by the cooler at the top of the quenching section after passing through the recycled water buffer tank and into the quenching stripper.

[0062] And / or, the stripping purified water from the bottom of the stripping tower is pressurized by the bottom pump of the stripping tower and then undergoes a primary waste heat exchange with a small portion of the bottom waste water through a primary heat exchanger; preferably, after the primary waste heat exchange, the stripping purified water is cooled by a stripping purified water cooler, and a portion of it is recycled back to the washing section of the quenching washing tower as washing water, while the other portion of the stripping purified water is discharged to the biochemical treatment device; or, after the primary waste heat exchange, a portion of the stripping purified water undergoes a secondary waste heat exchange with the washing wastewater through a secondary heat exchanger and is then recycled back to the washing section of the quenching washing tower, while the other portion is cooled by a stripping purified water cooler and discharged to the biochemical treatment device;

[0063] And / or, the material inside the stripper is heated by the stripper reboiler;

[0064] And / or, the oxygen-containing gas phase extracted from the top of the stripping tower is condensed by the stripping tower top cooler and then enters the stripping tower top gas-liquid separator. The condensed liquid phase is pressurized from the top of the stripping tower by the stripping tower top reflux pump and then completely refluxed back into the stripping tower for recycling. The oxygen-containing gas phase enters the downstream incineration system after condensation.

[0065] And / or, the enhanced elution circulating water is pressurized by the enhanced elution circulating pump and divided into a first part of enhanced elution circulating water and a second part of enhanced elution circulating water;

[0066] And / or, the elution wastewater is pressurized by the elution wastewater transfer pump of the quench elution tower and then merged with a small portion of the tower bottom wastewater before entering the stripping tower for stripping.

[0067] The positive and progressive effects of this utility model are as follows:

[0068] 1) In this utility model, the bottom wastewater of the quenching and washing tower is sent to the stripping tower for treatment, avoiding direct discharge of the bottom wastewater of the quenching and washing tower, reducing the amount of wastewater discharged and avoiding COD exceeding the standard in the discharged wastewater.

[0069] 2) In this utility model, the formaldehyde washing tower is reduced, and the acid washing and formaldehyde washing are completed simultaneously in a quenching washing tower. This avoids the acetaldehyde-containing generated gas coming out of the top of the quenching washing tower from the acetaldehyde condensation in the generated gas compressor system, which would cause blockage of the inter-section pipeline, thereby reducing equipment costs and lowering investment expenses.

[0070] 3) In this utility model, a portion of the stripping purified water at the bottom of the stripping tower is recycled back to the quenching and stripping tower as washing water, which can significantly reduce the amount of fresh water used, reduce wastewater output and stripping energy consumption.

[0071] 4) For existing industrially operating equipment, the oxygen-containing compound removal system of this invention can be used without large-scale modification, additional investment, or energy consumption.

[0072] 5) The single-stage enhanced circulation elution method is adopted in the elution section of the quenching elution tower, which can increase the circulating water volume in the elution section to elute oxides in the generated gas. Compared with the multi-stage enhanced circulation elution in existing industrial technologies, the process is simpler and consumes less energy.

[0073] 6) A branch line for washing wastewater is also provided at the position of the high concentration of acetaldehyde-rich liquid in the washing section of the quenching and washing tower. The high concentration of acetaldehyde-rich liquid is sent into the stripping tower for stripping, which solves the problem of acetaldehyde accumulation inside the quenching and washing tower, enhances the acetaldehyde washing effect, reduces the overall washing water load of the quenching and washing tower, and reduces the energy consumption of the stripping tower.

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

[0075] 8) The top of the quenching and washing tower is supplemented with industrial circulating water and wastewater treated and recycled water, preferably wastewater treated and recycled water.

[0076] 9) The top of the stripping tower adopts a liquid phase total reflux form. The gas phase at the top of the stripping tower gas-liquid separator is sent to the downstream incineration system for treatment, and the liquid phase at the bottom of the stripping tower gas-liquid separator is all returned to the top of the stripping tower. This avoids the existing industrial units from discharging the liquid phase wastewater at the bottom of the stripping tower gas-liquid separator, which would cause the wastewater COD to exceed the standard and affect subsequent treatment.

[0077] 10) The stripping tower adopts low-pressure operation, with an operating pressure of 0~0.2MPag, preferably 0.03~0.1MPag. The low operating pressure greatly reduces the steam consumption of the stripping tower reboiler and minimizes the energy consumption of the unit. Attached Figure Description

[0078] Figures 1-4 This is a process flow diagram of the present invention;

[0079] Figure 5 This is a process flow diagram of the existing technology. Detailed Implementation

[0080] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0081] Option 1:

[0082] like Figure 1 As shown, the product gas 1 after the butene oxidative dehydrogenation reaction is cooled and enters the product gas-liquid separator V1. The gas 2 at the top of the separator is sent to the quench section of the quenching and washing tower T1 to contact the washing water in the tower to remove oxygen-containing compounds such as acid and acetaldehyde. The product gas 16 at the top of the quenching and washing tower T1, after being washed and having oxygen-containing compounds removed, enters the downstream product gas compression system. The wastewater 3 from the bottom of the gas-liquid separator V1 is mixed with the wastewater outlet 4 from the bottom of the quenching and washing tower T1. After being pressurized by the bottom pump P2 of the quenching and washing tower, most of the bottom wastewater is cooled by the lower cooler E2 of the quenching and washing tower from the main wastewater line 5. This mixture then mixes with the enhanced washing circulating water from the enhanced washing circulating water line 7 of the washing section of the quenching and washing tower T1, which is pressurized by the enhanced washing circulating pump P1, and is distributed to the upper part of the quenching section of the quenching and washing tower T1. A small portion of the bottom wastewater is sent to the stripping tower T2 after heat exchange with the stripping purified water from the bottom wastewater branch line 17 via the primary heat exchanger E3. The enhanced washing circulating water from the enhanced washing circulating water line 7 is pressurized by the enhanced washing circulating pump P1 and then branched into the upper branch line 8. This mixture is then mixed with the alkali solution in the alkali solution inlet pipe 9 to perform enhanced washing of oxygen-containing compounds in the generated gas within the tower. Reclaimed water 12 is transported by reclaimed water buffer tank V2, then by reclaimed water transfer pump P4 and cooled by upper cooler E1 of quench stripping tower before being sent to the top of the stripping section of quench stripping tower T1. Stripped purified water after stripping in stripping tower T2 is pressurized by bottom pump P3 in purified water circulation loop 24 and then undergoes a heat exchange with the bottom wastewater from quench stripping tower T1 via primary heat exchanger E3. After being cooled by stripped purified water cooler E4, it is divided into two parts. One part is returned to the upper section of quench stripping tower T1 and mixed with enhanced stripping circulation water from upper branch 8 and alkali solution from alkali solution inlet pipe 9 before being sent into quench stripping tower T1. The other part is discharged from stripped purified water outlet branch 25 to the downstream biochemical treatment unit. Wastewater in stripper T2 is stripped by heating in the stripper reboiler E5. The oxygen-containing gas phase 19 collected from the top of stripper T2 is cooled by the stripper top cooler E6 and then enters the stripper top gas-liquid separator V3. The gas phase 21 at the top of the stripper top gas-liquid separator V3 goes to the downstream incineration system, and the liquid phase 22 at the bottom is pressurized by the stripper top reflux pump P5 and then returned to the upper part of stripper T2.

[0083] Option 2:

[0084] like Figure 2As shown, the product gas 1 after the butene oxidative dehydrogenation reaction is cooled and enters the product gas-liquid separator V1. The gas 2 at the top of the separator is sent to the quench section of the quenching and washing tower T1 to contact the washing water in the tower to remove oxygen-containing compounds such as acid and acetaldehyde. The product gas 16 at the top of the quenching and washing tower T1, after being washed and having oxygen-containing compounds removed, enters the downstream product gas compression system. After the wastewater 3 from the bottom of the gas-liquid separator V1 is mixed with the wastewater outlet pipe 4 from the bottom of the quenching and washing tower, it is pressurized by the bottom pump P2 of the quenching and washing tower. Most of the bottom wastewater is cooled by the lower cooler E2 of the quenching and washing tower from the main wastewater line 5. It is then mixed with the enhanced washing circulating water from the lower branch line 10 of the enhanced washing circulating water line 7 of the washing section of the quenching and washing tower T1 after being pressurized by the enhanced washing circulating pump P1. The mixture then returns to the upper part of the quenching section of the quenching and washing tower T1. A small portion of the bottom wastewater is sent to the stripping tower T2 after exchanging heat with the stripping purified water from the bottom wastewater branch line 17 and the primary heat exchanger E3. The stripping section of the quenching and washing tower T1 takes enhanced washing circulating water from the enhanced washing circulating water line 7. After being pressurized by the enhanced washing circulating pump P1, the water is mixed with the alkali inlet pipe 9 in the upper branch line 8 and then used for enhanced washing of oxygen-containing compounds in the generated gas. Reclaimed water 12, after passing through reclaimed water buffer tank V2, is pumped by reclaimed water transfer pump P4 and mixed with stripped purified water 26. It is then cooled by the upper cooler E1 of the quench stripping tower and sent to the top of the stripping section of quench stripping tower T1. Stripped purified water from stripping tower T2 is pressurized by the bottom pump P3 in the purified water circulation loop 24 and undergoes a heat exchange with the bottom wastewater from quench stripping tower T1 in the primary heat exchanger E3. After cooling by stripped purified water cooler E4, it is divided into two parts. One part 11 returns to the upper section of quench stripping tower T1 and is sent into quench stripping tower T1. The other part 26, mixed with reclaimed water 14, is cooled by the upper cooler E1 and enters the top of the stripping section of quench stripping tower T1. The remaining portion of stripped purified water cooled by stripped purified water cooler E4 is discharged from stripped purified water discharge branch 25 to the downstream biochemical treatment unit. Wastewater in stripper T2 is stripped by heating in the stripper reboiler E5. The oxygen-containing gas phase 19 collected from the top of stripper T2 is cooled by the stripper top cooler E6 and then enters the stripper top gas-liquid separator V3. The gas phase 21 at the top of the stripper top gas-liquid separator V3 goes to the downstream incineration system, and the liquid phase 22 at the bottom is pressurized by the stripper top reflux pump P5 and then returned to the upper part of stripper T2.

[0085] Option 3:

[0086] like Figure 3As shown, the product gas 1 from the butene oxidative dehydrogenation reaction is cooled and then enters the product gas-liquid separator V1. The top gas 2 is sent to the quench section of the quench stripper T1 to contact the washing water inside the tower to remove acids and oxygen-containing compounds such as acetaldehyde. The product gas 16 from the top of the quench stripper T1, after being washed to remove oxygen-containing compounds, enters the downstream product gas compression system. The bottom wastewater 3 of the product gas-liquid separator V1 is mixed with the bottom wastewater outlet pipe 4 of the quench stripper and then pressurized by the bottom pump P2 of the quench acid washing tower. Most of the bottom wastewater is cooled by the lower cooler E2 of the quench stripper from the main bottom wastewater line 5 and then returned to the upper part of the quench section of the quench stripper T1. A small portion of the bottom wastewater is sent to the stripper T2 after exchanging heat with the stripping purified water through the primary heat exchanger E3 from the bottom wastewater branch line 17. Reclaimed water 12 is transported via reclaimed water buffer tank V2 and then via reclaimed water transfer pump P4. After being cooled by the upper cooler E1 of the quench stripping tower, it is sent to the top of the stripping section of the quench stripping tower T1. Stripped purified water after stripping in stripping tower T2 is pressurized by the bottom pump P3 of the stripping tower through the purified water circulation loop 24 and undergoes a heat exchange with the bottom wastewater from the quench stripping tower T1 in the primary heat exchanger E3. After being cooled by the stripping purified water cooler E4, it is divided into two parts. One part is further divided into a portion 8 and mixed with the alkali solution inlet pipe 9 and sent to the stripping section of the quench stripping tower T1. The other part 10 is mixed with reclaimed water 16 and cooled by the upper cooler E1 before being sent to the top of the stripping section of the quench stripping tower T1. The other part 25 of the stripping purified water cooled by the stripping circulating water cooler E4 goes to the downstream biochemical treatment unit through the stripping purified water discharge branch 25. Wastewater in stripper T2 is stripped by heating in the stripper reboiler E5. The oxygen-containing gas phase 19 collected from the top of stripper T2 is cooled by the stripper top cooler E6 and then enters the stripper top gas-liquid separator V3. The gas phase 21 at the top of the stripper top gas-liquid separator V3 goes to the downstream incineration system, and the liquid phase 22 at the bottom is pressurized by the stripper top reflux pump P5 and then returned to the upper part of stripper T2.

[0087] Option 4:

[0088] like Figure 4As shown, the product gas 1 after the butene oxidative dehydrogenation reaction is cooled and enters the product gas-liquid separator V1. The gas 2 at the top of the separator is sent to the quench section of the quenching and washing tower T1 to contact the washing water in the tower to remove oxygen-containing compounds such as acid and acetaldehyde. The product gas 16 at the top of the quenching and washing tower T1, after being washed and having oxygen-containing compounds removed, enters the downstream product gas compression system. After the wastewater 3 from the bottom of the gas-liquid separator V1 is mixed with the wastewater outlet pipe 4 from the bottom of the quenching and washing tower, it is pressurized by the bottom pump P2 of the quenching and washing tower. Most of the wastewater from the bottom of the tower is cooled by the cooler E2 at the bottom of the quenching and washing tower from the main wastewater line 5 and then returned to the upper part of the quenching section of the quenching and washing tower T1. A small portion of the wastewater from the bottom of the tower is mixed with the acetaldehyde-rich high-concentration liquid 28 drawn from the washing wastewater branch line 26 of the washing section of the quenching and washing tower T1 from the bottom wastewater branch line 17. After the mixture is mixed with the stripping purified water at the bottom of the stripping tower T2, it is sent to the stripping tower T2 after a heat exchange in the primary heat exchanger E3. In the quenching stripping tower T1, the acetaldehyde-rich high-concentration liquid collected from the quenching wastewater branch 26 is pressurized by the quenching wastewater transfer pump P1, and after heat exchange with the stripping purified water 29 in the secondary heat exchanger E7, it is mixed with the tower bottom wastewater branch 17 and sent into the stripping tower T1 for stripping to enhance the acetaldehyde removal effect of the quenching stripping tower. The recycled water 12 is transported from the recycled water buffer tank V2 and then transported by the recycled water transfer pump P4, mixed with the stripping purified water 10, cooled by the upper cooler E1 of the quenching stripping tower, and sent to the top of the quenching acid washing tower T1. The stripped purified water after stripping in stripping tower T2 is pressurized by the bottom pump P3 in the stripping purified water circulation loop 24 and then mixed with the bottom wastewater 17 from the quench washing tower T1 in the primary heat exchanger E3. The purified water is then divided into two parts. One part, stripped purified water 29, is mixed with the acetaldehyde-rich high-concentration liquid 27 extracted from the quenching section of the quenching washing tower T1 in the secondary heat exchanger E7. This mixture is then further divided into two parts: one part (8) is mixed with the alkali solution in the alkali inlet pipe 9 and sent to the quenching section of the quenching washing tower T1; the other part (10) is mixed with recycled water 16 and cooled by the upper cooler E1 before being sent to the top of the quenching washing tower T1. The remaining portion (30) of the stripped purified water after the first waste heat exchange is cooled by the stripped purified water cooler E4 and then discharged from the stripped purified water discharge branch 25 to the downstream biochemical treatment unit. Wastewater in stripper T2 is stripped by heating in the stripper reboiler E5. The oxygen-containing gas phase 19 collected from the top of stripper T2 is cooled by the stripper top cooler E6 and then enters the stripper top gas-liquid separator V3. The gas phase 21 at the top of the stripper top gas-liquid separator V3 goes to the downstream incineration system, and the liquid phase 22 at the bottom is pressurized by the stripper top reflux pump P5 and then returned to the upper part of stripper T2.

[0089] Example 1:

[0090] A process for removing oxygen-containing compounds from the butene oxidative dehydrogenation gas, according to Scheme 1. Figure 1The butene oxidative dehydrogenation product gas 1, with a temperature of 90℃, a pressure of 50 kPag, and a flow rate of 135 t / h, enters the product gas-liquid separator V1. Gas 2 from the top of the separator enters the quenching and washing tower T1. Wastewater 3 from the separator and wastewater 4 from the bottom of the quenching and washing tower are pressurized by the bottom pump P2. Most of the wastewater 5 from the bottom of the tower, with a flow rate of 500 t / h, is cooled by the lower cooler E2. The resulting wastewater 6 from the bottom of the quenching and washing tower T1 enters the upper part of the quenching section, where it rapidly cools the product gas and washes away oxygen-containing impurities. A smaller portion of the wastewater 17 from the bottom of the tower, with a flow rate of 213.8 t / h, and stripping purified water 24, after primary heat exchange in the primary heat exchanger E3, enter the top of the stripping tower T2. The enhanced elution circulating water 7 extracted from the elution section of the quenching and elution tower T1 is pressurized by the enhanced elution circulating pump P1 and divided into two sections, returning to the elution section of the quenching and elution tower T1 to remove oxygen-containing compounds. The first section of enhanced elution circulating water 8, with a flow rate of 150 t / h, is sent to the elution section of the quenching and elution tower T1 along with the alkaline solution 9 to wash away acidic substances from the generated gas. The second section of enhanced elution circulating water 10, with a flow rate of 100 t / h, is circulated back to the upper part of the quenching section of the quenching and elution tower T1 along with the bottom wastewater 6. To ensure the quality of oxygen-containing compound removal from the top product gas 16 of the quenching and elution tower T1, a stream of recycled water 12 with a flow rate of 15 t / h is added to the top of the quenching and elution tower T1. After passing through the recycled water buffer tank V2, the recycled water 12 is pressurized by the recycled water transfer pump P4 and cooled to 5°C by the upper cooler E1 before entering the top of the quenching and elution tower T1. Stripping column T2 has 20 theoretical plates, with a top pressure of 0.05 MPaG. The bottom of stripping column T2 is heated by steam via stripping column reboiler E5. The oxygen-containing gas phase 19 at the top of stripping column T2 is cooled to 40°C via stripping column top condenser E6. The condenser outlet 20 undergoes gas-liquid separation in stripping column top gas-liquid separator V3. The acetaldehyde-rich gas phase 21 is sent to the downstream incineration system, while the aldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by stripping column top reflux pump P5 and then sent back into stripping column T2. ​​To reduce acetaldehyde polymerization in the top condenser, a polymerization inhibitor of 0.4 kg / h is added to the condenser inlet line. The stripping purified water 24 from stripping tower T2 undergoes heat exchange with the tower bottom wastewater 17 via heat exchanger E3 and cooling via stripping purified water cooler E4. 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 quench elution tower T1 and then enters the elution section of quench elution tower T1. The remaining stripping purified water 25 with a flow rate of 97.9 t / h is sent as wastewater to the downstream biochemical treatment unit for biochemical treatment.

[0091] Example 2

[0092] A process for removing oxygen-containing compounds from the butene oxidative dehydrogenation gas, according to Scheme 2. Figure 2The butene oxidative dehydrogenation product gas 1, with a temperature of 90℃, a pressure of 50 kPag, and a flow rate of 135 t / h, enters the product gas-liquid separator V1. The top gas 2 enters the quenching and washing tower T1. The bottom wastewater 3 and the bottom wastewater 4 of the quenching and washing tower T1 are pressurized by the bottom pump P2. Most of the bottom wastewater 5 (flow rate 500 t / h) is cooled by the lower cooler E2 and then enters the quenching section of the quenching and washing tower T1 to quench and wash away oxygen-containing impurities from the product gas. Another portion of the bottom wastewater 4 from the quenching and washing tower T1, with a flow rate of 309 t / h, after being pressurized by the bottom pump P2, and the stripping purified water 24 undergoes a primary heat exchange in the primary heat exchanger E3 before entering the top of the stripping tower T2. The enhanced elution circulating water 7 extracted from the elution section of the quenching and elution tower T1 is pressurized by the enhanced elution circulating pump P1 and divided into two sections, returning to the elution section of the quenching and elution tower T1 to remove oxygen-containing compounds. The first section of enhanced elution circulating water 8, with a flow rate of 200 t / h, is sent to the elution section of the quenching and elution tower T1 along with the alkaline solution 9 to wash away acidic substances from the generated gas. The second section of enhanced elution circulating water 10, with a flow rate of 50 t / h, is circulated back to the upper part of the quenching section of the quenching and elution tower T1 along with the bottom wastewater 6. To ensure the quality of oxygen-containing compound removal from the top product gas 16 of the quenching and elution tower T1, a stream of recycled water 12 with a flow rate of 15 t / h is added to the top of the quenching and elution tower T1. This recycled water 12, after passing through the recycled water buffer tank V2, is pressurized by the recycled water transfer pump P4 and cooled to 10°C by the upper cooler E1 before entering the top of the quenching and elution tower T1. Stripping column T2 has 20 theoretical plates, with a top pressure of 0.05 MPaG. The bottom of stripping column T2 is heated by steam via the stripping column reboiler E5. The oxygen-containing gas phase 19 at the top of stripping column T2 is cooled to 40°C via the stripping column top condenser E6. The condenser outlet 20 undergoes gas-liquid separation in the stripping column top gas-liquid separator V3. The acetaldehyde-rich gas phase 21 is sent to the downstream incineration system, while the aldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by the stripping column top reflux pump P5 and then sent back into stripping column T2. ​​To reduce acetaldehyde polymerization in the top condenser, a polymerization inhibitor at a rate of 0.4 kg / h is added to the condenser inlet line. The stripping purified water 24 from the bottom of stripping tower T2 undergoes heat exchange with the tower bottom wastewater 17 via heat exchanger E3 and cooling via stripping purified water cooler E4. The second stripping purified water 11, with a flow rate of 30 t / h, enters the washing section of quench stripping tower T1. The first stripping purified water 26, with a flow rate of 180 t / h, mixes with pressurized recycled water 14 and is cooled to 10°C via the upper cooler E1 of the quench stripping tower before entering the top of quench stripping tower T1. The remaining stripping purified water 25, with a flow rate of 98 t / h, is discharged as wastewater to the downstream biological treatment unit for biological treatment.

[0093] Example 3

[0094] A process for removing oxygen-containing compounds from the butene oxidative dehydrogenation gas, according to Scheme 3. Figure 3 The butene oxidative dehydrogenation product gas 1, with a temperature of 90℃, a pressure of 50 kPag, and a flow rate of 135 t / h, enters the product gas-liquid separator V1. The top gas 2 enters the quenching and washing tower T1. The bottom wastewater 3 and the bottom wastewater 4 of the quenching and washing tower T1 are pressurized by the bottom pump P2. Most of the bottom wastewater 5, with a flow rate of 500 t / h, is cooled by the lower cooler E2 and then enters the quenching section of the quenching and washing tower T1 to quench and wash away oxygen-containing impurities from the product gas. The remaining bottom wastewater 17, with a flow rate of 309 t / h, and the stripping purified water 24 undergo a primary heat exchange in the primary heat exchanger E3 before entering the top of the stripping tower T2. To ensure the quality of oxygen-containing compound removal from the top product gas 16 of the quench stripper T1, a stream of recycled water 12 with a flow rate of 15 t / h is added to the top of the quench stripper T1. After passing through the recycled water buffer tank V2, the recycled water 12 is pressurized by the recycled water transfer pump P4 and cooled to 10°C by the upper cooler E1 before entering the top of the quench stripper T1. The stripper T2 has 20 theoretical plates, with a top pressure of 0.05 MPaG. The bottom of the stripper T2 is heated by steam via the stripper reboiler E5. The oxygen-containing gas phase 19 at the top of the stripper T2 is cooled to 40°C by the stripper top condenser E6. The condenser outlet 20 undergoes gas-liquid separation in the stripper top gas-liquid separator V3. The acetaldehyde-rich gas phase 21 is sent to the downstream incineration system, while the aldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by the stripper top reflux pump P5 and then sent back into the stripper T2. To mitigate acetaldehyde polymerization in the top condenser of the tower, a polymerization inhibitor of 0.4 kg / h is added to the condenser inlet pipeline. The stripping purified water 24 from stripping tower T2 undergoes primary heat exchange with the bottom wastewater 17 via heat exchanger E3 and is cooled by stripping purified water cooler E4. The second stripping purified water 8 (30 t / h) and alkali solution 9 then enter the elution section of quenching and stripping tower T1. The first stripping purified water 10 (180 t / h) is mixed with pressurized recycled water 14 and cooled to 10°C by the upper cooler E1 before entering the top of quenching and stripping tower T1. The remaining stripping purified water 25 (98 t / h) is discharged as wastewater and sent to the downstream biological treatment unit for biological treatment.

[0095] Example 4

[0096] A process for removing oxygen-containing compounds from the butene oxidative dehydrogenation gas, according to Scheme 4. Figure 4The butene oxidative dehydrogenation product gas 1, with a temperature of 90℃, a pressure of 50 kPag, and a flow rate of 135 t / h, enters the product gas-liquid separator V1. The top gas 2 enters the quenching and washing tower T1. The bottom wastewater 3 and the bottom wastewater 4 of the quenching and washing tower T1 are pressurized by the bottom pump P2. Most of the bottom wastewater 5, with a flow rate of 500 t / h, is cooled by the lower cooler E2. The resulting bottom wastewater 6 enters the quenching section of the quenching and washing tower T1 to quench and wash away oxygen-containing impurities from the product gas. Another portion of the bottom wastewater 4, with a flow rate of 309 t / h, is mixed with the washing wastewater 28 extracted from the washing section of the quenching and washing tower T1. After a single heat exchange with the stripping purified water 24 in the primary heat exchanger E3, 18 the mixture enters the top of the stripping tower T2. The washing wastewater 26 extracted from the washing section of the quench washing tower T1 is pressurized by the washing wastewater transfer pump P1 and then exchanged with the secondary waste heat of the stripped purified water 29 in the secondary heat exchanger E7. After mixing with the bottom wastewater 17 of the quench washing tower T1, it exchanges with the primary waste heat of the stripped purified water 24 in the primary heat exchanger E3 before entering the stripping tower T2. The stripping tower T2 has 20 theoretical plates, and the top pressure is 0.05 MPaG. The bottom of the stripping tower T2 is heated by steam through the stripping tower reboiler E5. The oxygen-containing gas phase 19 at the top of stripping tower T2 is cooled to 40°C by the top condenser E6. The condenser outlet 20 undergoes gas-liquid separation in the top gas-liquid separator V3. The acetaldehyde-rich gas phase 21 is sent to the downstream incineration system, while the aldehyde-containing condensate phase 22 at the bottom of the separator is pressurized by the top reflux pump P5 and then sent back into stripping tower T2. To reduce acetaldehyde polymerization in the top condenser, a polymerization inhibitor of 0.4 kg / h is added to the condenser inlet line. The stripping purified water 24 from stripping tower T2 is separated into two streams after heat exchange with the bottom wastewater 17 in primary heat exchanger E3. One stream, stripping purified water 29 with a flow rate of 30 t / h, is mixed with the wastewater 27 from the quenching and washing section of quenching and washing tower T1, which is pressurized by the wastewater transfer pump P1. After heat exchange in secondary heat exchanger E7, a portion of the second stripping purified water 8 is mixed with alkali solution 9 and enters the washing section of quenching and washing tower T1. The other portion, first stripping purified water 10 with a flow rate of 180 t / h, is mixed with recycled water 12 from the outside with a flow rate of 15 t / h, pressurized by recycled water buffer tank V2 and recycled water transfer pump P4, and then cooled by upper section cooler E1 before entering quenching and washing tower T1. The remaining stripping purified water 30 with a flow rate of 98 t / h is cooled by stripping purified water cooler E4 and then sent as wastewater to the downstream biological treatment unit for biological treatment.

[0097] Comparative Example

[0098] A process for removing oxygen-containing compounds from the butene oxidative dehydrogenation gas, according to... Figure 5The butene oxidative dehydrogenation product gas 1, with a temperature of 90℃, a pressure of 50 kPag, and a flow rate of 135 t / h, enters the product gas-liquid separator V1. Gas 2 from the top of the separator enters the quenching acid washing tower T1. Wastewater 3 from the bottom of the separator, along with wastewater 4 from the bottom of the quenching acid washing tower T1, is pressurized by the 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 the quenching acid washing tower T1 along with the product gas entering the tower. The upper section of the quenching acid washing tower T1 undergoes two stages of water washing and cooling to remove oxygen-containing compounds. The upper section's circulation 11 has a water flow rate of 217 t / h, with circulation flow 13 at 200 t / h and circulation flow 14 at 17 t / h. The middle section's circulation 7 has a water flow rate of 218 t / h, with circulation flow 8 at 202 t / h and circulation flow 10 at 16 t / h. Wastewater 4 from the bottom of the quench acid washing tower T1 is pressurized by the bottom pump P3. Part of the wastewater 5 is returned to the quench acid washing tower T1, while part of the wastewater 17 is mixed with condensate 25 separated from the gas-liquid separator V2 at the top of the stripping tower and sent for biochemical treatment. The generated gas 16 from the top of the quench acid washing tower T1 is pressurized to 1.35 MPa by compressor C1 and then sent to the aldehyde washing tower T3. The wash water used in the aldehyde washing tower T2 is the circulating wash water 30 after stripping, with a flow rate of 220 t / h. Fresh water 12 is added at a rate of 16 t / h. The generated gas 19 from the top of the aldehyde washing tower T2 is sent to the downstream oil washing unit. Wastewater 20 from the bottom of the aldehyde washing tower T2 is sent to the stripping tower T2 after heat exchange in the primary heat exchanger E3. To reduce the polymerization of acetaldehyde in the top condenser, a polymerization inhibitor of 1 kg / h is added to the condenser inlet pipeline. The purified water 26 from the bottom of stripping tower T3 passes through heat exchanger E3 for primary heat exchange and cooler E4 before entering the top of aldehyde washing tower T2. Stripping tower T3 has 20 theoretical plates, with a top pressure of 0.3 MPag. The bottom reboiler E5 is heated with steam. The top gas 22 from stripping tower T3 is cooled to 40°C by the top condenser E6. The condenser outlet 23 undergoes gas-liquid separation in the top tank V2. Acetaldehyde-rich gas 24 is sent out of the boundary 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 washing tower and sent to the biochemical treatment unit.

[0099] Table 1 Comparison of results from Examples 1-4 and Comparative Examples 2

[0100]

[0101] In summary, this invention, by feeding the wastewater from the bottom of the quenching and washing tower T1 into the stripping tower T2 for treatment, results in a significantly lower COD value compared to the wastewater discharged in the comparative example, thus solving the problem of excessive COD in wastewater. Simultaneously, this invention reduces the use of the aldehyde washing tower, avoiding the problem of acetaldehyde agglomeration in the compressor system caused by the high acetaldehyde concentration in the generated gas from the top of the quenching tower, which could lead to blockage of the inter-stage pipelines. Furthermore, the acetaldehyde concentration in the washed generated gas is not significantly higher than in the comparative example, simplifying the process and reducing equipment costs. The lower operating pressure also significantly reduces steam consumption compared to the comparative example, greatly reducing steam consumption in the stripping tower reboiler and lowering stripping energy consumption. Moreover, by feeding a portion of the stripping purified water from the bottom of the stripping tower T1 into the washing section of the quenching and washing tower T1 as washing water, the amount of fresh water used is significantly reduced, wastewater output is decreased, and investment costs are lowered.

[0102] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those 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, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A system for removing oxygenate compounds from a reaction gas produced in the oxidation dehydrogenation of butene to butadiene, characterized by The system includes: Generative gas-liquid separator; A quenching and elution tower has a quenching section in the lower part and an elution section in the upper part. The quenching section of the quenching and elution tower is connected to the upper gas phase of the generated gas in the generated gas-liquid separator. The bottom of the quenching and elution tower is provided with a bottom wastewater outlet pipe. The bottom wastewater outlet pipe is connected to the upper part of the quenching section by a main bottom wastewater channel that returns most of the bottom wastewater to the upper part of the quenching section. The stripping tower has a branch line between the bottom wastewater outlet of the quench washing tower and the inlet of the stripping tower, which allows a small portion of the bottom wastewater to be fed into the bottom wastewater of the stripping tower.

2. The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation to butadiene production reaction as described in claim 1, characterized in that, The elution section of the quenching elution tower has an elution wastewater branch at the location of the high concentration of acetaldehyde-rich liquid. The elution wastewater branch is merged with the bottom wastewater branch and then connected to the inlet of the stripping tower.

3. The system for removing oxygenates from the reaction gas produced in the oxidation dehydrogenation of butene to butadiene according to claim 2, characterized in that, The elution wastewater branch first exchanges heat with the secondary waste heat of the stripping purified water in the bottom of the stripping tower, then merges with the bottom wastewater branch, then exchanges heat with the primary waste heat of the stripping purified water in the bottom of the stripping tower, and finally connects to the inlet of the stripping tower.

4. The system for removing oxygenates from the reaction gas produced in the oxidation dehydrogenation of butene to butadiene according to claim 1, characterized in that, The top of the quenching and washing tower is directly connected to the downstream generated gas compression system.

5. The system for removing oxygenates from the reaction gas produced in the oxidation dehydrogenation of butene to butadiene according to claim 1, characterized in that, The top of the stripping tower is connected to a stripping tower top gas-liquid separator. All the liquid phase in the stripping tower top gas-liquid separator is returned to the upper part of the stripping tower, and the gas phase in the stripping tower top gas-liquid separator enters the downstream incineration system.

6. The system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation reaction to butadiene as described in claim 5, characterized in that, A stripping tower top cooler is also connected between the top of the stripping tower and the stripping tower top gas-liquid separator to cool the gas phase at the top of the stripping tower.

7. The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation reaction to butadiene as described in claim 2, characterized in that, There is also a stripping purified water circulation loop between the stripping tower bottom and the elution section of the quench elution tower, in which the stripping purified water from the stripping tower bottom is circulated back to the elution section. An alkaline solution inlet pipe is provided on the elution section of the quenching and elution tower; A return water pipeline is installed at the upper part of the elution section of the quenching elution tower.

8. The system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation reaction to butadiene as described in claim 7, characterized in that, The stripping purified water circulation loop is also connected to a stripping purified water discharge branch that discharges a portion of the stripping purified water into the downstream biochemical treatment device.

9. The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation reaction to butadiene as described in claim 7, characterized in that, The stripping purification water circulation loop is combined with the alkali inlet pipe and then connected to the elution section of the quenching and elution tower.

10. The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation to butadiene reaction as described in claim 7, characterized in that, The latter part of the stripping purified water circulation loop is branched and connected to the first branch of the stripping purified water circulation loop and the second branch of the stripping purified water circulation loop. The first branch of the stripping purified water circulation and the recycled water pipeline are combined and connected to the upper part of the elution section of the quenching and elution tower; the second branch of the stripping purified water circulation is connected to the elution section of the quenching and elution tower.

11. The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation to butadiene production reaction as described in claim 10, characterized in that, The second branch of the stripping purified water circulation is combined with the alkali inlet pipe and then connected to the elution section of the quenching and elution tower.

12. The system for removing oxygen-containing compounds from the gas generated during the butene oxidative dehydrogenation to butadiene production reaction as described in claim 7, characterized in that, The elution section of the quenching elution tower is also equipped with an enhanced elution circulating water path. The latter part of the enhanced elution circulating water path branches into an upper branch and a lower branch. The lower branch of the enhanced elution circulating water path is connected to the upper part of the quenching section after merging with the main wastewater path of the quenching section. The upper branch of the enhanced elution circulating water path is connected to the alkali inlet pipe after merging with the elution section of the quenching elution tower.

13. The system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation reaction to butadiene as described in claim 12, characterized in that, The upper branch of the enhanced elution circulating water circuit, the alkali inlet pipe, and the stripping purification water circulating circuit are combined and connected to the elution section of the quench elution tower. Alternatively, the latter part of the stripping purified water circulation loop may be branched into a first branch and a second branch; the first branch of the stripping purified water circulation may be connected to the upper part of the elution section of the quenching and elution tower after merging with the recycled water pipeline; the second branch of the stripping purified water circulation may be connected to the elution section of the quenching and elution tower; the upper branch of the enhanced elution circulation water circuit may be connected to the elution section of the quenching and elution tower after merging with the alkali inlet pipe; or, the upper branch of the enhanced elution circulation water circuit, the alkali inlet pipe, and the second branch of the stripping purified water circulation may be connected to the elution section of the quenching and elution tower.

14. The system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation reaction to butadiene as described in claim 1, characterized in that, The wastewater from the bottom of the gas-liquid separator is connected to the wastewater outlet pipe of the tower bottom.

15. The system for removing oxygen-containing compounds from the gas produced in the butene oxidative dehydrogenation reaction to butadiene as described in any one of claims 7 to 13, characterized in that, The main pipeline for the wastewater from the bottom of the tower is equipped with a quenching and washing tower at the lower end of the cooling tower for the wastewater from the bottom of the tower. And / or, the recycled water pipeline is equipped with a quenching stripper at the top of the cooling water stripper and a recycled water delivery pump.

16. The system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation reaction to butadiene as described in claim 8, characterized in that, The stripping purified water circulation loop is equipped with a primary heat exchanger that exchanges heat with the wastewater branch of the tower bottom; preferably, the stripping purified water circulation loop is equipped with a stripping purified water cooler for cooling the stripping purified water after the primary heat exchange, or the stripping purified water circulation loop is equipped with a secondary heat exchanger that exchanges heat with the stripping purified water branch after the primary heat exchange, and the stripping purified water discharge branch is equipped with a stripping purified water cooler for cooling the discharged stripping purified water. And / or, the stripping tower reboiler is provided with a stripping tower reboiler; And / or, a quenching and washing bottom pump is provided on the wastewater branch of the tower bottom, and a stripping bottom pump for pressurizing stripping purified water is provided at the bottom of the stripping tower; And / or, the bottom of the stripping tower top gas-liquid separator has a stripping tower top reflux pump; And / or, the elution wastewater branch is equipped with a quench elution tower elution wastewater transfer pump.

17. The system for removing oxygen-containing compounds from the gas generated in the butene oxidative dehydrogenation reaction to butadiene as described in claim 12, characterized in that, An enhanced elution circulation pump is installed on the enhanced elution circulation water line.

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