CN211435653U - System for cyclic utilization epoxypropane tail gas - Google Patents
System for cyclic utilization epoxypropane tail gas Download PDFInfo
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- CN211435653U CN211435653U CN201921861978.1U CN201921861978U CN211435653U CN 211435653 U CN211435653 U CN 211435653U CN 201921861978 U CN201921861978 U CN 201921861978U CN 211435653 U CN211435653 U CN 211435653U
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Abstract
The utility model provides a system for cyclic utilization epoxypropane tail gas, system for cyclic utilization epoxypropane tail gas is including the separator, remove methanol device, catalytic oxidation device, drying device and the pressure swing adsorption equipment that connect gradually. The utility model discloses utilize the pressure swing adsorption device to retrieve, purify the nitrogen gas in the epoxypropane tail gas, the nitrogen gas after the purification is optional returns to epoxypropane synthesis system after the pressure boost and recycles, has not only reduced the tail gas emission, has reduced the emission burning of methyl alcohol, can also reduce the nitrogen gas quantity by a wide margin, practices thrift the tail gas treatment cost; the pressure swing adsorption device provided by the utility model is used for recovering the epoxypropane tail gas, the recovery rate of nitrogen is more than or equal to 85 percent, and the recovery rate of methanol is more than or equal to 95.5 percent; the purity of the obtained nitrogen is more than or equal to 99.9 percent, and the oxygen content is less than 0.01 percent.
Description
Technical Field
The utility model belongs to the technical field of the environmental protection, a tail gas processing system is related to, especially relate to a system of cyclic utilization epoxypropane tail gas.
Background
Propylene Oxide (PO) is an important basic organic chemical raw material, the PO is mainly used for producing polyether, propylene glycol and isopropanolamine, and can also be used as a main raw material of a surfactant, a demulsifier and a pesticide emulsifier, and derivatives of the PO are widely applied to industries such as automobiles, buildings, food, tobacco, cosmetics and the like and are important raw materials of fine chemical products.
At present, methods for producing PO comprise a chlorohydrin method, an oxidation method and a hydrogen peroxide oxidation method (HPPO method), wherein the HPPO method is a novel propylene oxide production method, the method can overcome the defects of serious corrosion of the chlorohydrin method to equipment, more waste liquid and more waste residues, and the method does not have the defects of more co-oxidation method coproducts, and is an internationally recognized environment-friendly production method at present. The method has the advantages of simple process, high product yield, no pollution and high byproduct value.
The HPPO method utilizes direct epoxidation reaction of hydrogen peroxide and propylene to generate propylene oxide, during the epoxidation reaction, hydrogen peroxide is inevitably decomposed to generate oxygen, and the oxygen, propylene, propane and other combustible gases form a mixed gas, so that the HPPO method has deflagration risk and seriously threatens the safe production of the propylene oxide by the HPPO method.
In order to solve the problem of excessive oxygen and easy combustion and explosion industrially, nitrogen is generally introduced into a reaction system, the oxygen content in the system is controlled to be below the explosion limit, then the reaction liquid is introduced into a deoxygenation tower, and a large amount of nitrogen is introduced to extract and separate oxygen dissolved in the reaction liquid, so that the flash explosion risk in the subsequent propylene flash evaporation and propylene oxide refining processes is reduced, but the method has high nitrogen consumption, and the generated waste gas contains a large amount of volatile organic pollutants such as propylene, methanol, propylene oxide and the like, and can meet the emission requirement of GB16297-1996 only by carrying out innocent treatment.
CN 105017178A discloses a deoxidation method of HPPO process mixed gas, which arranges a deoxidation reactor between a circulating propylene compressor and a propylene buffer tank, the process mixed gas and hydrogen gas enter the deoxidation reactor after being mixed by a gas mixer, and contact with a catalyst, and the oxygen gas and hydrogen gas are reacted by the catalyst, thereby achieving the purpose of deoxidation. However, the method also needs to add hydrogen, and the tail gas of the HPPO method contains less oxygen, so that the method needs to consume excessive hydrogen, and the tail gas composition is more complicated.
CN 109748888A discloses a method for removing oxygen in HPPO process recycle gas, which comprises adding a deoxidation connecting pipeline between a recycle propylene compressor and a propylene buffer tank, wherein the deoxidation connecting pipeline is provided with a deoxidation reactor, the outlet end of the recycle propylene compressor is provided with a first oxygen content detector, and the deoxidation reactor is started to perform deoxidation when the first oxygen content detector reaches a preset value. However, the method only involves the reaction removal of oxygen in the tail gas by using a catalyst, still has the problem of large nitrogen consumption, and is not beneficial to energy conservation and emission reduction.
CN 110003050A discloses a method and a device for preparing acrylonitrile by recycling HPPO process waste gas, which comprises a deoxygenation tower, a condensing tank, an acrylonitrile reaction tower, an ammonia neutralization tower and an absorption tower which are connected in sequence. Waste gas generated in the HPPO process is firstly introduced into a condensing tank to recover high-boiling-point organic pollutants, then the waste gas containing propylene, oxygen and nitrogen and supplemented ammonia gas are introduced into an acrylonitrile reactor, the propylene, the oxygen and the ammonia gas are subjected to ammoxidation reaction under the action of a catalyst to generate acrylonitrile, the propylene and the oxygen in the waste gas are consumed, and the separated nitrogen gas can be returned to the HPPO process for recycling after reactants are separated. However, the method needs additional ammonia gas, which is not favorable for long-time cyclic utilization of nitrogen.
Therefore, the system which can save energy and reduce the oxygen content in the epoxypropane tail gas is provided, and the system has important significance for energy conservation and emission reduction in the process of synthesizing epoxypropane by the HPPO method.
SUMMERY OF THE UTILITY MODEL
Not enough to prior art exists, the utility model aims to provide a cyclic utilization epoxypropane tail gas's system, this system utilize pressure swing adsorption device to retrieve, purify the nitrogen gas in the epoxypropane tail gas, through the optional back epoxypropane synthesis system of returning to of nitrogen gas after the purification after the pressure boost retrieval and utilization, not only reduced the exhaust emission, reduced the emission burning of methyl alcohol, can also reduce the nitrogen gas quantity by a wide margin, practice thrift the tail gas treatment cost.
To achieve the purpose, the utility model adopts the following technical proposal:
the utility model provides a system for cyclic utilization epoxypropane tail gas, system for cyclic utilization epoxypropane tail gas is including the separator, remove methanol device, catalytic oxidation device, drying device and the pressure swing adsorption equipment that connect gradually.
The content of nitrogen in the epoxypropane tail gas is 86-93 wt%, the content of oxygen is 6-10 wt%, the content of propylene is 0.5-1 wt%, and the content of methanol is 0.5-2 wt%; carrying out primary gas-liquid separation on the epoxypropane tail gas in a separation device, removing methanol from the separated gas in a methanol removing device, and recovering methanol removed from the separation device and the methanol removing device for later use; removing combustible components such as propylene and the like in the catalytic oxidation device from the gas from which the methanol is removed, and removing moisture in a drying device; and finally, removing oxygen in a pressure swing adsorption device to obtain nitrogen with purity meeting the recycling requirement.
Preferably, the separation device is a gas-liquid separation device.
Preferably, the gas-liquid separation device comprises a liquid separation tank. The gas-liquid separation device not only comprises a liquid separation tank, but also comprises a liquid separation kettle and/or a liquid separation tower. That is, the gas-liquid separation device of the present invention is a conventional container having a gas-liquid separation function in the field, and those skilled in the art can select a suitable specification according to actual needs.
Preferably, the demethanizer is a wash column. The detergent used by the washing tower is water, and is removed by washing
Preferably, the catalytic oxidation device comprises a preheater, a heat exchanger and a catalytic oxidation reactor which are connected in sequence.
The preheater and the heat exchanger of the utility model are heat exchangers commonly used in the field, wherein the heat source of the preheater is a reaction product in a catalytic oxidation reactor, and the heat exchanger uses an external heat source to heat the preheated gas after methanol removal to the temperature required by the reaction; the catalytic oxidation reactor is any one of a fixed bed reactor, a fluidized bed reactor or a moving bed reactor which is used for loading catalyst and is conventional in the field, and can be reasonably selected by a person skilled in the art according to actual needs.
The utility model discloses utilize tail gas from the oxygen in area to oxidize combustible gas such as propylene, wherein the oxygen in the tail gas is excessive, can guarantee that combustible gas oxidizes completely, need not additionally to supply air and oxygen.
Preferably, the drying means comprises a gas drying tower.
Drying device includes gas drying tower, still includes gas dryer and/or gas drying tank. That is, the drying device of the present invention is a container having a drying function, which is conventional in the art, and a person skilled in the art can select a suitable specification according to actual needs.
Preferably, the pressure swing adsorption unit comprises at least three pressure swing adsorption columns connected in series.
The utility model discloses utilize the pressure swing adsorption tower to adsorb the oxygen in the dry back tail gas to realize the separation of nitrogen gas and oxygen. The adsorbed oxygen and other gases are desorbed and then used for emptying combustion.
Preferably, the system for recycling the propylene oxide tail gas further comprises a buffer tank and/or a gas pressurization device, and the buffer tank and the gas pressurization device are respectively and independently connected with the pressure swing adsorption device.
Preferably, the system for recycling the propylene oxide tail gas further comprises a buffer tank and a gas pressurization device, wherein the buffer tank is arranged on a connecting pipeline between the pressure swing adsorption device and the gas pressurization device.
The high-purity nitrogen discharged by the pressure swing adsorption device is buffered by a buffer tank and then pressurized by a gas pressurizing device, so that the nitrogen meets the requirement of the nitrogen required by the HPPO method.
Preferably, the gas booster device is a gas booster pump.
Use the utility model discloses a system for cyclic utilization epoxypropane tail gas include following step:
(1) separating the epoxypropane tail gas by a separation device, and then removing methanol by water in a methanol removing device, wherein the recovery rate of the methanol is more than or equal to 95.5%;
(2) the gas after methanol removal is subjected to catalytic oxidation to remove combustible media such as propylene in tail gas;
(3) the gas obtained in the step (2) enters a drying device to remove moisture in the gas;
(4) the gas obtained in the step (3) enters a pressure swing adsorption device to remove oxygen and other components, so that high-purity nitrogen is obtained;
(5) and (4) introducing the high-purity nitrogen obtained in the step (4) into a buffer tank, and recycling the nitrogen after being pressurized by a gas pressurizing device to a system for synthesizing propylene oxide by an HPPO method.
After the recovery, the rate of recovery of tail gas is more than or equal to 85% among the epoxypropane, just the utility model provides a system's simple structure, cyclic utilization in-process resistance drops and < 0.05 MPa.
The system refers to an equipment system, or a production equipment.
Compared with the prior art, the beneficial effects of the utility model are that:
(1) the utility model discloses utilize the pressure swing adsorption device to retrieve, purify the nitrogen gas in the epoxypropane tail gas, the nitrogen gas after the purification is optional returns to epoxypropane synthesis system after the pressure boost and recycles, has not only reduced the tail gas emission, has reduced the emission burning of methyl alcohol, can also reduce the nitrogen gas quantity by a wide margin, practices thrift the tail gas treatment cost;
(2) the pressure swing adsorption device provided by the utility model is used for recovering the epoxypropane tail gas, the recovery rate of nitrogen is more than or equal to 85 percent, and the recovery rate of methanol is more than or equal to 95.5 percent; the purity of the obtained nitrogen is more than or equal to 99.9 percent, and the oxygen content is less than 0.01 percent.
Drawings
FIG. 1 is a schematic diagram of the system for recycling propylene oxide tail gas provided in example 1;
fig. 2 is a schematic structural diagram of a system for recycling a propylene oxide tail gas according to embodiment 2.
Wherein: 1, a separation device; 2, a methanol removing device; 3-1, a preheater; 3-2, a heat exchanger; 3-3, a catalytic oxidation reactor; 4, a drying device; 5, a pressure swing adsorption device; 6, a buffer tank; and 7, a gas supercharging device.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.
Example 1
The embodiment provides a system for recycling propylene oxide tail gas, and a schematic structural diagram of the system for recycling propylene oxide tail gas is shown in fig. 1, and the system comprises a separation device 1, a methanol removal device 2, a catalytic oxidation device, a drying device 4 and a pressure swing adsorption device 5.
The separation device 1 is a liquid separation tank; the methanol removing device 2 is a washing tower; the catalytic oxidation device comprises a preheater 3-1, a heat exchanger 3-2 and a catalytic oxidation reactor 3-3 which are connected in sequence, wherein a heat source of the preheater 3-1 is a reaction product in the catalytic oxidation reactor 3-3; the drying device 4 is a gas drying tower; the pressure swing adsorption device 5 comprises 3 stages of pressure swing adsorption towers connected in series.
The system for recycling the propylene oxide tail gas provided by the embodiment comprises the following steps:
(1) after the liquid of the epoxypropane tail gas is separated by the separation device 1, the epoxypropane tail gas enters a methanol removing device 2 to remove methanol by using water, and the recovery rate of the methanol is more than or equal to 95.5 percent;
(2) the gas after methanol removal is subjected to catalytic oxidation to remove combustible media such as propylene in tail gas;
(3) the gas obtained in the step (2) enters a drying device 4 to remove moisture in the gas;
(4) and (4) introducing the gas obtained in the step (3) into a pressure swing adsorption device 5, and removing oxygen and other components to obtain high-purity nitrogen.
The purity of the obtained high-purity nitrogen is more than or equal to 99.9 percent, the oxygen content is less than 0.01 percent,the recovery rate of the nitrogen is more than or equal to 85 percent, the resistance reduction during the recovery is less than 0.05MPa, and the pressure of the high-purity nitrogen obtained in the step (4) is more than or equal to 1.95 MPa. Taking 40 ten thousand tons of HPPO propylene oxide production systems as an example, the tail gas emission is 10250Nm391.6% by weight of nitrogen, 6% by weight of oxygen, 0.5% by weight of propylene and 1.8% by weight of methanol, 8285Nm of nitrogen being recoverable3The nitrogen recovery was 87.1%.
Example 2
The embodiment provides a system for recycling propylene oxide tail gas, and a schematic structural diagram of the system for recycling propylene oxide tail gas is shown in fig. 2, and the system comprises a separation device 1, a methanol removal device 2, a catalytic oxidation device, a drying device 4, a pressure swing adsorption device 5, a buffer tank 6 and a gas pressurization device 7.
The separation device 1 is a liquid separation tank; the methanol removing device 2 is a washing tower; the catalytic oxidation device comprises a preheater 3-1, a heat exchanger 3-2 and a catalytic oxidation reactor 3-3 which are connected in sequence, wherein a heat source of the preheater 3-1 is a reaction product in the catalytic oxidation reactor 3-3; the drying device 4 is a gas drying tower; the pressure swing adsorption device 5 comprises 3 stages of pressure swing adsorption towers connected in series. The buffer tank 6 is arranged on a connecting pipeline between the 3 rd-stage pressure swing adsorption device 5 and the gas supercharging device 7.
The system for recycling the propylene oxide tail gas provided by the embodiment comprises the following steps:
(1) after the liquid of the epoxypropane tail gas is separated by the separation device 1, the epoxypropane tail gas enters a methanol removing device 2 to remove methanol by using water, and the recovery rate of the methanol is more than or equal to 95.5 percent;
(2) the gas after methanol removal is subjected to catalytic oxidation to remove combustible media such as propylene in tail gas;
(3) the gas obtained in the step (2) enters a drying device 4 to remove moisture in the gas;
(4) the gas obtained in the step (3) enters a pressure swing adsorption device 5, oxygen and other components are removed, and high-purity nitrogen is obtained;
(5) and (4) introducing the high-purity nitrogen obtained in the step (4) into a buffer tank 6, and recycling the nitrogen after being pressurized by a gas pressurizing device 7 to a system for synthesizing propylene oxide by an HPPO method.
The purity of the obtained high-purity nitrogen is more than or equal to 99.9 percent, the oxygen content is less than 0.01 percent, the recovery rate of the nitrogen is more than or equal to 85 percent, the resistance in the recovery process is reduced to less than 0.05MPa, and the pressure of the high-purity nitrogen obtained in the step (4) is more than or equal to 1.95 MPa. Taking 40 ten thousand tons of HPPO propylene oxide production systems as an example, the tail gas emission is 10250Nm391.6% by weight of nitrogen, 6% by weight of oxygen, 0.5% by weight of propylene and 1.8% by weight of methanol, 8285Nm of nitrogen being recoverable3The nitrogen recovery was 87.1%.
To sum up, the utility model utilizes the pressure swing adsorption device 5 to recover and purify the nitrogen in the epoxypropane tail gas, the purified nitrogen can be returned to the epoxypropane synthesis system for recycling after being pressurized, thereby not only reducing the tail gas emission and the emission and combustion of methanol, but also greatly reducing the nitrogen consumption and saving the tail gas treatment cost; the pressure swing adsorption device 5 provided by the utility model is used for recovering the epoxypropane tail gas, the recovery rate of nitrogen is more than or equal to 85 percent, and the recovery rate of methanol is more than or equal to 95.5 percent; the purity of the obtained nitrogen is more than or equal to 99.9 percent, and the oxygen content is less than 0.01 percent.
The applicant states that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and those skilled in the art should understand that any changes or substitutions easily conceivable by those skilled in the art within the technical scope of the present invention are within the protection scope and the disclosure scope of the present invention.
Claims (10)
1. The system for recycling the propylene oxide tail gas is characterized by comprising a separation device, a methanol removing device, a catalytic oxidation device, a drying device and a pressure swing adsorption device which are sequentially connected.
2. The system for recycling propylene oxide off-gas according to claim 1, wherein the separation device is a gas-liquid separation device.
3. The system for recycling propylene oxide off-gas according to claim 2, wherein the gas-liquid separation device comprises a liquid separation tank.
4. The system for recycling propylene oxide tail gas according to claim 1, wherein the methanol removal unit is a scrubber.
5. The system for recycling propylene oxide off-gas according to claim 1, wherein the catalytic oxidation device comprises a preheater, a heat exchanger and a catalytic oxidation reactor which are connected in sequence.
6. The system for recycling propylene oxide off-gas according to claim 1, wherein the drying means comprises a gas drying tower.
7. The system for recycling propylene oxide off-gas of claim 1, wherein the pressure swing adsorption unit comprises at least three pressure swing adsorption columns connected in series.
8. The system for recycling propylene oxide off-gas according to claim 1, further comprising a buffer tank and/or a gas pressurization device, wherein the buffer tank and the gas pressurization device are respectively and independently connected to the pressure swing adsorption device.
9. The system for recycling propylene oxide off-gas according to claim 1, further comprising a buffer tank and a gas pressurizing device, wherein the buffer tank is disposed on the connection pipeline between the pressure swing adsorption device and the gas pressurizing device.
10. The system for recycling propylene oxide off-gas according to claim 8 or 9, wherein the gas booster device is a gas booster pump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921861978.1U CN211435653U (en) | 2019-10-31 | 2019-10-31 | System for cyclic utilization epoxypropane tail gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921861978.1U CN211435653U (en) | 2019-10-31 | 2019-10-31 | System for cyclic utilization epoxypropane tail gas |
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| CN211435653U true CN211435653U (en) | 2020-09-08 |
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| CN201921861978.1U Active CN211435653U (en) | 2019-10-31 | 2019-10-31 | System for cyclic utilization epoxypropane tail gas |
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