CN210786898U - N in caprolactam production waste gas2System for co-processing O and VOC - Google Patents
N in caprolactam production waste gas2System for co-processing O and VOC Download PDFInfo
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- CN210786898U CN210786898U CN201921648822.5U CN201921648822U CN210786898U CN 210786898 U CN210786898 U CN 210786898U CN 201921648822 U CN201921648822 U CN 201921648822U CN 210786898 U CN210786898 U CN 210786898U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/30—Improvements relating to adipic acid or caprolactam production
Abstract
The utility model discloses a N in caprolactam waste gas2System for co-processing of O and VOC, according to the exhaust gas flow directionThe method comprises a gas storage device, a water washing device, a gas diluting device, a catalytic reaction device, a flue gas monitoring device and an exhaust device in sequence, wherein caprolactam production waste gas enters the water washing device from the gas storage device, enters the catalytic reaction device after pretreatment, is subjected to oxidation-reduction reaction under the action of a catalyst, and products are detected by the flue gas monitoring device to be discharged through the exhaust device. The utility model discloses utilize N in caprolactam waste gas for the first time2Oxidation co-processing of tert-butyl alcohol, N in waste gas from caprolactam production by O2The conversion rate of O is 99.99 percent, the conversion rate of tert-butyl alcohol is 99.78-99.87 percent, the purpose of treating wastes with wastes is realized, the method is a technical innovation in the field of energy conservation and environmental protection, and has economical efficiency, practicability and industrial application prospect.
Description
Technical Field
The utility model belongs to the environmental protection field, concretely relates to N in caprolactam waste gas2A system for co-processing O and VOC.
Background
Caprolactam is one of important basic organic chemical raw materials, is mainly used for producing nylon 6 engineering plastics and nylon 6 fibers, and is widely applied to the fields of electronics, automobiles, textiles, machinery and the like. At present, cyclohexanone ammoximation technology is mostly adopted to produce caprolactam in China, main process units comprise a hydrogen peroxide preparation device, a cyclohexanone production device, a cyclohexanone ammoximation device, a caprolactam refining device and a thiamine recovery device, the cyclohexanone ammoximation device is a core process, hydrogen peroxide, cyclohexanone and ammonia are adopted to synthesize cyclohexanone oxime under the action of a titanium catalyst by taking tert-butyl alcohol as a solvent under the condition of low pressure, and the chemical reaction formula is as follows:
main reaction: NH (NH)3+H2O2+C6H10O＝C6H11ON+2H2O
Side reaction: 4H2O2+2NH3＝N2O+7H2O
3H2O2+2NH3＝N2+6H2O
2H2O2＝O2+2H2O
The waste gas generated in the process of producing caprolactam is mainly composed of N2O, tert-butanol, water vapor, NH3、O2And N2Etc. in which N is2O is a greenhouse gas and the latent heat of warming is CO2310 times of, CH421 times of, N2Every 1-fold increase in atmospheric concentration of O will result in a global temperature rise of 0.3K, N2O is very stable in the atmosphere, has a lifetime of 120 years or more, and N is2O can also destroy ozone in the atmosphere to form acid rain, which is extremely harmful to the ecological environment, thereby controlling N2The emission of O is crucial to environmental protection.
The tertiary butanol in the waste gas generated in caprolactam production is a Volatile Organic Compound (VOC), and the VOC has great harm to human bodies, can cause the maladjustment of the immune level of organisms, influences the functions of the central nervous system, causes symptoms such as dizziness, headache, somnolence, weakness, chest distress and the like to people, and can damage the digestive system, the liver function, the hematopoietic system and the like in severe cases. The VOC is not only a primary pollution source, but also a precursor of ozone and photochemical reaction, can cause ozone pollution and photochemical smog pollution, and causes serious harm to human health and ecological environment, so that the control of the emission of tert-butyl alcohol has important significance for VOC emission reduction.
N in waste gas from caprolactam production2The volume concentration of O is more than 60000ppm, and the mass concentration of tert-butyl alcohol is more than 10000mg/m3High concentration of N2O and tertiary butanol are directly discharged into the atmosphere, so that the quality of the atmospheric environment is inevitably reduced, serious harm is brought to the ecological environment, and great loss is caused to national economy, therefore, the waste gas generated in caprolactam production needs to be purified before being discharged, so that N is generated2The content of atmospheric pollutants such as O, tertiary butanol and the like reaches the limit value of the emission standard. The conventional treatment process of waste gas generated in caprolactam production comprises the following steps: (1) the waste gas is absorbed by a circulating water condenser and a desalted water absorption tower to recover most NH3And tert-butanol; (2) from desalinated waterThe waste gas discharged from the absorption tower contains N2O, tertiary butanol, water vapor and the like continuously enter a tail gas reactor for catalytic treatment, the tail gas reactor is an adiabatic fixed bed reactor, and Rh-Al is filled in the tail gas reactor2O3Catalyst, N2The removal rate of O reaches 99.9 percent; (3) and introducing the treated waste gas into a tail gas absorption tower, using active carbon as an adsorbent, and emptying the waste gas after purification.
Researchers at home and abroad have extensively studied the treatment of waste gas generated in caprolactam production, for example, CN201510635007.5 discloses a caprolactam tail gas treatment method and a device, which comprises an absorption unit, an adsorption unit and a reflux unit, wherein concentrated sulfuric acid, hydrogen peroxide and other absorption liquids are utilized in the absorption unit to treat NOXAnd SOXCircularly absorbing, and further absorbing NO in the exhaust gas by using an adsorbent after entering the absorption unitXAnd SOXThe purpose of purifying the waste gas is achieved, the adsorbent is repeatedly utilized after being analyzed by the vacuum pump, and the high-concentration NO generated by analysisXAnd SOXThen enters an absorption unit for cyclic absorption, the method does not treat VOC in the waste gas generated in the caprolactam production, and high-concentration NO is generatedXAnd SOXThe absorption is circulated in the device, so that equipment corrosion and energy waste are caused, and a large amount of waste absorption liquid is generated in the treatment process, so that potential pollution is caused to the environment. CN201510076772.8 discloses a method for purifying waste gas in caprolactam production by using Fe-zeolite catalyst, and extra NH is introduced into a catalytic reactor3As a reducing agent, N can be simultaneously reduced at the reaction temperature of 300-400 DEG C2O and NO, but NH introduced by the process3Is also one of the atmospheric pollutants, the waste gas needs additional treatment, and the method does not treat the waste gas VOC generated in the caprolactam production.
In summary, in the prior art, the VOC in the waste gas from caprolactam production is mainly from the product or raw material in the reaction process, and an additional waste gas treatment device is required in the production equipment, which results in high cost and poor efficiency, but even so, the VOC content after the whole waste gas treatment process still remains high, so how to find the cause of the VOC in the caprolactam production process and effectively treat the VOC becomes a technical problem to be solved urgently.
Disclosure of Invention
In view of the above technical problems, the present invention has creatively found that tertiary butanol as a solvent is the main source of waste gas VOC from caprolactam production in caprolactam production, but this technical problem is not recognized in the prior art. However, the existing technology for treating VOC has low efficiency and high cost when treating tert-butanol, and needs to additionally introduce an oxidizing substance, which increases the production and operation costs of enterprises, and due to the introduction of the oxidizing substance, the safety is greatly reduced, and serious safety accidents such as explosion are easily caused. Based on aforementioned reason, VOC content is difficult to reach national environmental protection emission standard all the time in caprolactam waste gas production, just to these problems, the utility model provides an utilize N in caprolactam waste gas production2The system for treating the VOC generated in the caprolactam production process by using O does not need to additionally increase a special treatment device or additionally increase an oxidizing substance, and can realize effective treatment of the VOC in the caprolactam production waste gas.
The utility model provides a N in caprolactam waste gas2The system for co-processing O and VOC utilizes N in the waste gas under the action of catalyst2The active oxygen atom generated by O and the tertiary butanol in the waste gas are subjected to oxidation-reduction reaction to realize the N in the waste gas generated in the production of caprolactam2And the O and the tert-butyl alcohol are cooperatively treated, so that the aims of cooperatively performing denitration and VOC emission reduction and treating wastes with wastes are fulfilled.
The utility model provides a N in caprolactam waste gas2The system for the co-processing of O and VOC is characterized by comprising a gas storage device, a water washing device, a gas diluting device, a catalytic reaction device, a flue gas monitoring device and an exhaust device in sequence according to the flow direction of waste gas.
Further, the water washing device is of a spray tower type structure.
Further, the waste gas passes through the water washing device from bottom to top.
Further, the gas diluting device is a gas bag, wherein N is introduced2Diluting N in exhaust gas2The O concentration.
Further, the catalytic reaction device is an adiabatic fixed bed catalytic reactor.
Further, the catalyst bed layer of the adiabatic fixed-bed catalytic reactor is filled with a honeycomb catalyst.
Further, the catalyst is a zeolite molecular sieve based metal catalyst.
Further, waste gas passes through the pipeline and gets into gas storage device, gas storage device's upper portion pass through the pipeline with water washing device's bottom is connected, water washing device's upper portion is provided with the shower head, the shower head passes through the pipe connection with the water pump, and the shower water passes through the water pump gets into the shower head, to water washing device's inside sprays shower water, waste water by water washing device's bottom is discharged, water washing device's upper portion pass through the pipeline with the upper portion of gas bag is connected, the middle part of gas bag lets in N2The gas bag is used for diluting internal gas, the gas bag pass through the pipeline with catalytic reaction device's well upper portion is connected, catalytic reaction device's well lower part pass through the pipeline with flue gas monitoring device connects, flue gas monitoring device's the pipeline of giving vent to anger divide into two, one with gas storage device connects for with the unqualified gas circulation of monitoring returns gas storage device continues to handle, and another is connected with the draught fan, is used for passing through the qualified gas of monitoring the draught fan transmits the chimney discharges to the atmosphere.
The treatment conditions were as follows:
the flow of the waste gas entering the water washing device is 8000-15000 m3/h。
N before the waste gas enters the water washing device2The volume concentration of O is more than or equal to 300000 ppm.
Before the waste gas enters the water washing device, the concentration of the tertiary butanol is more than or equal to 10000mg/m3。
The waste gas passes through the water washing device from bottom to top.
After the waste gas is treated by the water washing device, a part of tert-butyl alcohol in the waste gas is condensed and absorbed, and is discharged to a water treatment unit from the bottom of the water washing device along with waste water.
The gas diluting device is a gas bag, wherein N is introduced2Diluting N in exhaust gas2The O concentration.
Said N is2The flow rate of (A) is 30000-40000 m3/h。
The catalytic reaction device is an adiabatic fixed bed catalytic reactor.
Further, the adiabatic fixed-bed catalytic reactor is a radial adiabatic fixed-bed catalytic reactor or an axial adiabatic fixed-bed catalytic reactor.
Further, the adiabatic fixed bed catalytic reactor is a single-stage adiabatic fixed bed catalytic reactor, a 2-stage adiabatic fixed bed catalytic reactor, or a 3-stage adiabatic fixed bed catalytic reactor.
Further, the catalyst beds of the 2-stage adiabatic fixed-bed catalytic reactor or the 3-stage adiabatic fixed-bed catalytic reactor are directly connected.
Further, the catalyst bed layer of the adiabatic fixed-bed catalytic reactor is filled with a honeycomb catalyst.
Furthermore, the filling amount of the catalyst is 1000-5000 kg.
Further, the catalyst is prepared from a metal salt solution and a zeolite molecular sieve by adopting an impregnation method, wherein the metal salt is preferably nitrate, and the zeolite molecular sieve is preferably Beta molecular sieve.
Further, the catalyst is a zeolite molecular sieve based metal catalyst, preferably, the catalyst is Fe-Beta, Co-Beta or Cu-Beta.
Further, the waste gas is treated by the catalytic reaction device to obtain N2The volume concentration of O is 3-7 ppm.
Further, the concentration of the tert-butyl alcohol after the waste gas is treated by the catalytic reaction device is 2-5 mg/m3。
Further, the waste gas is processed by the system to obtain N2The conversion of O was 99.99%.
Furthermore, the conversion rate of the tert-butyl alcohol after the waste gas is treated by the system is 99.78-99.87%.
Further, the reaction product of the catalytic reaction device is N2、CO2And water.
Further, the reaction temperature of the catalytic reaction device is not lower than 450 ℃.
Further, the space velocity of the catalytic reaction device is 3000-5000 h-1。
Further, the flue gas monitoring device is an online flue gas monitoring device.
Further, exhaust apparatus includes draught fan and chimney.
Further, the emission standard of the exhaust device is the emission limit value of VOC 120mg/m in the Integrated emission Standard of air pollutants (GB16297-1996)3。
Further, the waste gas is treated by the system and then discharged to the atmosphere through an exhaust device.
Further, the height of the chimney is 10-15 meters.
The beneficial effects of the utility model
1. The inventive discovery of the present invention is that VOCs in caprolactam process gas are primarily caused by the solvent tertiary butanol, rather than VOCs that have been recognized in the prior art as being derived from reaction products or reactants. Based on this technical problem, current exhaust treatment device can not effective processing tert-butyl alcohol, and then, the utility model discloses utilize the N in caprolactam waste gas2The oxidation of O synergistically treats the tertiary butanol in the caprolactam waste gas to realize the N in the waste gas VOC produced by caprolactam2The treatment effect that the conversion rate of O is 99.99% and the conversion rate of tert-butyl alcohol is 99.78-99.87%, the waste gas VOC generated in caprolactam production can reach the emission standard, denitration and VOC emission reduction are carried out simultaneously, and the purpose of treating waste with waste is achieved.
2. Compared with the prior art, the utility model discloses realize simultaneously handling N in caprolactam waste gas for the first time2O and tertiary butanol, the system flow is simple, and equipment area is little, and safe easy operation does not need additionally to increase VOC processing apparatus, directly utilizes the utility model discloses a system realizes denitration and VOC's cooperation simultaneouslyAnd the utility model discloses used catalyst low cost, easily available and long service life greatly practice thrift the production and operation cost for the enterprise, have general industry spreading value.
3. Compared with the prior art, the utility model discloses need not additionally to add the oxidizing substance, also need not additionally to add the heat source, utilize fixed bed reactor's adiabatic temperature rise just can reach reaction temperature, the energy consumption is low, and the running cost is low, and operating mode safety, the controllability is strong, has economic nature, practicality and industrial application prospect.
4. The utility model discloses be used for the coprocessing of caprolactam waste gas with metal-loaded molecular sieve base catalyst for the first time, utilize N2The active oxygen atom generated by O and tert-butyl alcohol are subjected to oxidation-reduction reaction, and the reaction product is N2、CO2And water, nontoxic harmless, green, the process the utility model discloses caprolactam waste gas VOC index after system and method are handled is superior to the emission standard of national regulation, is favorable to the sustainable development of environment to the production and the operating cost of reduction enterprise that can be very big realize treating waste with waste, are the technological innovation in energy-concerving and environment-protective field.
Drawings
FIG. 1 shows N in waste gas from caprolactam production2Schematic system diagram of co-processing of O and VOC. In the figure, the gas storage device 1; a water pump 2; a water washing device 3; a gas bag 4; a catalytic reaction device 5; a flue gas monitoring device 6; an induced draft fan 7; a chimney 8.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention.
Example 1
N in caprolactam production waste gas2As shown in figure 1, the system for the co-processing of O and VOC comprises a gas storage device 1, a water pump 2, a water washing device 3, a gas bag 4, a catalytic reaction device 5, a flue gas monitoring device 6, an induced draft fan 7 and a chimney 8. The waste gas generated in caprolactam production enters a gas storage device 1 for buffering and then flows outThe waste gas enters the water washing device 3 from the upper part, and simultaneously, the spray water enters from the top of the water washing device 3 through the water pump 2, the tert-butyl alcohol in the waste gas is condensed and absorbed, the waste gas is discharged from the bottom of the water washing device 3 along with the waste water, the waste gas is continuously introduced into the gas bag 4, and N is introduced into the gas bag 42Diluting the waste gas to reduce N in the waste gas2The concentration of O and the pretreated waste gas enter a catalytic reaction device 5, and N in the waste gas is reacted under the action of a catalyst2O and tert-butyl alcohol are subjected to oxidation-reduction reaction in the catalytic reaction device 5, the high-efficiency co-processing waste gas is detected by the flue gas monitoring device 6, the standard-reaching waste gas is discharged to the atmosphere through the draught fan 7 via the chimney 8, and the substandard waste gas returns to the gas storage device 1 again for circular processing.
Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Claims (9)
1. N in caprolactam production waste gas2The system for the co-processing of O and VOC is characterized by comprising a gas storage device, a water washing device, a gas diluting device, a catalytic reaction device, a flue gas monitoring device and an exhaust device in sequence according to the flow direction of waste gas.
2. N in caprolactam production off-gas according to claim 12The system for the co-processing of O and VOC is characterized in that the water washing device is of a spray tower type structure.
3. N in caprolactam production off-gas according to claim 1 or 22The system for the co-processing of O and VOC is characterized in that the waste gas passes through a water washing device from bottom to top.
4. N in caprolactam production off-gas according to claim 12The system for the co-processing of O and VOC is characterized in that the gas diluting device is a gas bag, and N is introduced into the gas bag2Diluting N in exhaust gas2The O concentration.
5. N in caprolactam production off-gas according to claim 12The system for co-processing O and VOC is characterized in that the catalytic reaction device is an adiabatic fixed bed catalytic reactor.
6. N in caprolactam production off-gas according to claim 52The system for the co-treatment of O and VOC is characterized in that the catalytic bed layer of the adiabatic fixed-bed catalytic reactor is filled with honeycomb catalyst.
7. N in caprolactam production off-gas according to claim 62The system for the co-treatment of O and VOC is characterized in that the catalyst is a zeolite molecular sieve based metal catalyst.
8. N in caprolactam production off-gas according to claim 72The system for the Co-processing of O and VOC is characterized in that the catalyst is Fe-Beta, Co-Beta or Cu-Beta.
9. N in caprolactam production off-gas according to claim 42The system for the co-processing of O and VOC is characterized in that waste gas enters the gas storage device (1) through a pipeline, the upper portion of the gas storage device (1) is connected with the bottom of the water washing device (3) through a pipeline, a spray head is arranged on the upper portion of the water washing device (3) and is connected with a water pump (2) through a pipeline, spray water enters the spray head through the water pump (2) and is sprayed into the water washing device (3), waste water is discharged from the bottom of the water washing device (3), the upper portion of the water washing device (3) is connected with the upper portion of the gas bag (4) through a pipeline, N2 is introduced into the middle portion of the gas bag (4) and is used for diluting internal gas, the gas bag (4) is connected with the middle upper portion of the catalytic reaction device (5) through a pipeline, the middle lower portion of the catalytic reaction device (5) is connected with the flue gas monitoring device (6) through a pipeline, of the flue gas monitoring device (6)The gas outlet pipeline is divided into two parts, one part is connected with the gas storage device (1) and used for circulating the gas which is monitored to be unqualified back to the gas storage device (1) for continuous treatment, and the other part is connected with the induced draft fan (7) and used for transmitting the gas which is monitored to be qualified to the atmosphere through the induced draft fan (7) to the chimney (8) and discharging the gas to the atmosphere.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113649065A (en) * | 2021-09-27 | 2021-11-16 | 北京工业大学 | Method for synergistically purifying polycomponent tail gas of caprolactam by using metal catalyst and preparation method of metal catalyst |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113649065A (en) * | 2021-09-27 | 2021-11-16 | 北京工业大学 | Method for synergistically purifying polycomponent tail gas of caprolactam by using metal catalyst and preparation method of metal catalyst |
| CN113649065B (en) * | 2021-09-27 | 2023-09-15 | 北京工业大学 | Method for cooperatively purifying caprolactam multicomponent tail gas by using metal catalyst and preparation method of metal catalyst |
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