CN114768500A - Method for purifying and decomposing dicyandiamide tail gas - Google Patents
Method for purifying and decomposing dicyandiamide tail gas Download PDFInfo
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- CN114768500A CN114768500A CN202210371522.7A CN202210371522A CN114768500A CN 114768500 A CN114768500 A CN 114768500A CN 202210371522 A CN202210371522 A CN 202210371522A CN 114768500 A CN114768500 A CN 114768500A
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- dicyandiamide
- tail gas
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- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 title claims abstract description 120
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000000746 purification Methods 0.000 claims abstract description 45
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 31
- 238000010438 heat treatment Methods 0.000 claims abstract description 28
- 229920000877 Melamine resin Polymers 0.000 claims abstract description 17
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims abstract description 17
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000004202 carbamide Substances 0.000 claims abstract description 14
- 239000002994 raw material Substances 0.000 claims abstract description 12
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 239000007789 gas Substances 0.000 claims description 147
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 33
- 239000000203 mixture Substances 0.000 claims description 25
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 9
- 239000003546 flue gas Substances 0.000 claims description 9
- 238000005485 electric heating Methods 0.000 claims description 6
- 238000002425 crystallisation Methods 0.000 claims description 5
- 230000008025 crystallization Effects 0.000 claims description 5
- 238000006116 polymerization reaction Methods 0.000 claims description 5
- 238000000197 pyrolysis Methods 0.000 claims description 5
- 238000000926 separation method Methods 0.000 claims description 5
- 239000013078 crystal Substances 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 abstract description 21
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 abstract description 19
- 229910002092 carbon dioxide Inorganic materials 0.000 abstract description 13
- 229910021529 ammonia Inorganic materials 0.000 abstract description 9
- 239000001569 carbon dioxide Substances 0.000 abstract description 8
- 231100000331 toxic Toxicity 0.000 abstract 1
- 230000002588 toxic effect Effects 0.000 abstract 1
- XZMCDFZZKTWFGF-UHFFFAOYSA-N Cyanamide Chemical compound NC#N XZMCDFZZKTWFGF-UHFFFAOYSA-N 0.000 description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005265 energy consumption Methods 0.000 description 5
- OWIKHYCFFJSOEH-UHFFFAOYSA-N Isocyanic acid Chemical compound N=C=O OWIKHYCFFJSOEH-UHFFFAOYSA-N 0.000 description 4
- XLJMAIOERFSOGZ-UHFFFAOYSA-N anhydrous cyanic acid Natural products OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 230000005611 electricity Effects 0.000 description 3
- 239000003345 natural gas Substances 0.000 description 3
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 3
- ZFSLODLOARCGLH-UHFFFAOYSA-N isocyanuric acid Chemical compound OC1=NC(O)=NC(O)=N1 ZFSLODLOARCGLH-UHFFFAOYSA-N 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 201000004624 Dermatitis Diseases 0.000 description 1
- 238000001321 HNCO Methods 0.000 description 1
- 206010019233 Headaches Diseases 0.000 description 1
- 206010020772 Hypertension Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000747 cardiac effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 208000002173 dizziness Diseases 0.000 description 1
- 231100000869 headache Toxicity 0.000 description 1
- 239000011874 heated mixture Substances 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 230000007794 irritation Effects 0.000 description 1
- 231100000017 mucous membrane irritation Toxicity 0.000 description 1
- 208000024891 symptom Diseases 0.000 description 1
- 208000008203 tachypnea Diseases 0.000 description 1
- 206010043089 tachypnoea Diseases 0.000 description 1
- 231100000167 toxic agent Toxicity 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/005—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by heat treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/343—Heat recovery
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/76—Gas phase processes, e.g. by using aerosols
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2256/00—Main component in the product gas stream after treatment
- B01D2256/22—Carbon dioxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/408—Cyanides, e.g. hydrogen cyanide (HCH)
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
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Abstract
The invention relates to the technical field of dicyandiamide tail gas treatment, in particular to a method for purifying and decomposing dicyandiamide tail gas. The method comprises a production process of dicyandiamide by taking melamine or urea as a raw material, and a process of purifying and decomposing dicyandiamide tail gas through heat exchange, heating, purification and decomposition to obtain purified dicyandiamide tail gas. The method is simple and convenient to operate and easy to realize, toxic and harmful media in the tail gas are decomposed, simultaneously, raw materials which do not react completely are completely decomposed, and the purified dicyandiamide tail gas obtained after decomposition mainly comprises ammonia and carbon dioxide, so that the follow-up treatment is facilitated.
Description
Technical Field
The invention relates to the technical field of dicyandiamide tail gas treatment, in particular to a method for purifying and decomposing dicyandiamide tail gas.
Background
In the process of preparing dicyandiamide by taking melamine as raw material, dicyandiamide tail gas needs to be recycled, and NH in the dicyandiamide tail gas is recycled3And CO2But with small amounts of unreacted and by-products present in the off-gas, such as: melamine gas, cyanamide gas and the like can cause blockage and the like when the tail gas is reused, and need to be cleaned, thereby influencing the safe and stable operation of production.
In the process of preparing dicyandiamide by taking urea as a raw material, dicyandiamide tail gas needs to be recycled, and NH in the dicyandiamide tail gas is recycled3And CO2But with small amounts of unreacted and by-products present in the dicyandiamide tail gas, such as: isocyanic acid, cyanuric acid, cyanamide gas and the like can corrode and block equipment when tail gas is utilized, so that the utilization of the tail gas is influenced to a certain extent.
Cyanamide is a toxic substance, has irritation and corrosiveness to the skin, can cause severe dermatitis, and can cause symptoms such as mucous membrane irritation, headache, dizziness, tachypnea, excessive cardiac movement, hypertension and the like when being ingested or inhaled, so the cyanamide needs to be decomposed in tail gas, and the tail gas is prevented from being brought in when being reused, thereby causing harm.
Disclosure of Invention
The invention aims to provide a method for purifying dicyandiamide tail gas, which is characterized in that tail gas generated by preparing dicyandiamide from melamine or urea is subjected to purification and decomposition treatment on other components contained in the tail gas, and main components in the purified dicyandiamide tail gas obtained after decomposition are ammonia and carbon dioxide, so that the purified dicyandiamide tail gas can be better utilized.
In order to achieve the above purpose, the specific technical scheme of the invention is as follows:
the method for purifying the dicyandiamide tail gas comprises a production process of dicyandiamide by using melamine or urea as a raw material, and a process of purifying and decomposing the dicyandiamide tail gas through heat exchange, heating, purification and decomposition to obtain the purified dicyandiamide tail gas.
The production process of the dicyandiamide comprises the following steps: after the melamine or urea is subjected to the processes of pyrolysis, polymerization, crystallization, separation, washing and the like, dicyandiamide crystals are obtained, and the separated gas, namely dicyandiamide tail gas, is purified and decomposed.
A method for purifying melamine tail gas specifically comprises the following steps: the tail gas purification and decomposition process comprises the steps of mixing and preheating the dicyandiamide tail gas and water in a tail gas heat exchanger, then entering a tail gas heater for further heating, then introducing into a purification and decomposition device for purification and decomposition to obtain the dicyandiamide tail gas after purification and decomposition, and enabling the dicyandiamide tail gas after purification and decomposition to enter the tail gas heat exchanger for preheating a mixture of the dicyandiamide tail gas and the water to obtain the purified dicyandiamide tail gas.
The temperature of the dicyandiamide tail gas is 50-300 ℃, and the pressure is 0-1 MPa; the preferred temperature is 90-220 deg.C and pressure is 0-0.5 MPa.
The water is water vapor, and the mass ratio of the dicyandiamide tail gas to the water vapor is 10-1000: 1.
The preheating temperature of the mixture of the dicyandiamide tail gas and the water is 300-400 ℃.
After the dicyandiamide tail gas is preheated, the dicyandiamide tail gas is further heated in a tail gas heater, wherein the heating temperature is 350-550 ℃, and the heating mode comprises flue gas heating and/or electric heating, preferably flue gas heating.
The purification decomposer can be a fixed bed reactor.
The temperature of the purification decomposition is 350-550 ℃; the temperature of the dicyandiamide tail gas after purification and decomposition is 350-550 ℃.
After the mixture of the dicyandiamide and the water is preheated, the temperature of the purified dicyandiamide tail gas is 180-300 ℃.
Compared with the prior art, the invention has the following beneficial effects:
adding water into the tail gas heat exchanger to mix the water with the dicyandiamide tail gas to form a mixture, preheating the mixture by using the purified dicyandiamide tail gas, and fully using the waste heat of the dicyandiamide tail gas after purification and decomposition to heat the mixture of the dicyandiamide tail gas and the water, so that the energy consumption can be saved, the temperature of the purified dicyandiamide tail gas can be reduced, and the subsequent treatment is facilitated. When the mixture of water and dicyandiamide tail gas is preheated to 180 ℃, the cyanamide can be hydrolyzed into urea, and when the mixture is preheated to 300-400 ℃, the urea generated by the cyanamide can be hydrolyzed into ammonia and carbon dioxide, thereby achieving the purpose of purifying and decomposing the tail gas. The reaction equation involved in the process is:
(di) isocyanic acid is volatile and corrosive, is unstable in nature, and reacts with water to form ammonia and carbon dioxide, according to the equation:
HNCO+H2O＝CO2+NH3
and (III) preheating the dicyandiamide tail gas in a tail gas heat exchanger, further heating the tail gas by a tail gas heater, wherein the preheating temperature is lower than the heating temperature, heating the tail gas to 350-550 ℃, introducing the gas into a purification decomposer, instantly cracking melamine gas contained in the tail gas into cyanamide in the presence of ammonia, and hydrolyzing the cyanamide and water at a high temperature to finally generate ammonia and carbon dioxide. When the decomposition temperature is too low, the decomposition efficiency is lowered or even decomposition is impossible, and when the decomposition temperature is too high, energy is wasted and new by-products are generated.
And (IV) the tail gas heater in the method comprises flue gas heating and/or electric heating, the heating effect is better, the flue gas is preferably used for heating, the flue gas which is specific to a dicyandiamide device is used as a heating medium, the heating is convenient, and the energy consumption is saved.
And (V) after other components contained in the dicyandiamide tail gas are completely decomposed, finally obtaining ammonia and carbon dioxide which are the same as the ammonia and the carbon dioxide contained in the dicyandiamide tail gas, so that the aim of completely purifying and decomposing the tail gas is fulfilled, and only the ammonia and the carbon dioxide exist in the purified dicyandiamide tail gas, thereby facilitating the subsequent further utilization.
Description of the drawings:
fig. 1 is a schematic process flow diagram of a purification method of melamine off-gas according to the present invention.
Detailed Description
The method comprises a production process of dicyandiamide by using melamine or urea as a raw material, and a process of purifying and decomposing dicyandiamide tail gas through heat exchange, heating and purification decomposition to obtain purified dicyandiamide tail gas.
The dicyandiamide production process is that after melamine or urea is subjected to the processes of pyrolysis, polymerization, crystallization, separation, washing and the like, dicyandiamide crystals are obtained, and the separated gas, namely dicyandiamide tail gas, is purified and decomposed.
The tail gas purification and decomposition process comprises the steps of mixing and preheating dicyandiamide tail gas and water in a tail gas heat exchanger, further heating the mixture in a tail gas heater, purifying and decomposing the mixture in a purification and decomposition device to obtain purified and decomposed dicyandiamide tail gas, and preheating the mixture of the dicyandiamide tail gas and water in the tail gas heat exchanger to obtain the purified dicyandiamide tail gas.
The temperature of the dicyandiamide tail gas is 50-300 ℃, and the pressure is 0-1 MPa; preferably at a temperature of 90-220 deg.C and a pressure of 0-0.5 MPa.
The water is water vapor, and the mass ratio of the dicyandiamide tail gas to the water vapor is 10-1000: 1.
The preheating temperature of the mixture of the dicyandiamide tail gas and the water is 300-400 ℃.
After preheating the dicyandiamide tail gas, further heating the tail gas in a tail gas heater at the temperature of 350-550 ℃, wherein the heating mode comprises flue gas heating and/or electric heating, and preferably flue gas heating.
The purification decomposer can be a fixed bed reactor.
The temperature of the purification and decomposition is 350-550 ℃; the temperature of the dicyandiamide tail gas after purification and decomposition is 350-550 ℃.
After the mixture of dicyandiamide and water is preheated, the temperature of the purified dicyandiamide tail gas is 180-300 ℃.
In order to facilitate the understanding of the present invention, the process described in the present invention will be further described with reference to the accompanying drawings and the detailed description. It should not be understood that the scope of the above-described subject matter of the present invention is limited to the following examples.
The process comprises the steps of producing dicyandiamide by taking melamine or urea as a raw material, and purifying and decomposing dicyandiamide tail gas through heat exchange, heating and purification decomposition to obtain purified dicyandiamide tail gas.
Example 1
The method comprises the steps of taking melamine as a raw material, carrying out pyrolysis, polymerization crystallization, separation, washing and the like to obtain dicyandiamide crystals, wherein the separated gas, namely dicyandiamide tail gas (the mass ratio of components in the tail gas is slightly changed but the components are not changed greatly due to different operations of the pyrolysis, polymerization crystallization and separation steps), is required to be subjected to purification decomposition treatment at the temperature of 140 ℃ and the pressure of 0.3 MPa.
The method comprises the steps of forming a mixture of dicyandiamide tail gas and added water vapor (the mass ratio of the dicyandiamide tail gas to the water vapor is 10: 1), preheating the mixture to 350 ℃ in a tail gas heat exchanger, further heating the mixture to 460 ℃ by using flue gas in a tail gas heater, introducing the heated mixture into a purification decomposer (the purification decomposer adopts a fixed bed reactor), purifying and decomposing the mixture (the temperature of purification and decomposition is 460 ℃) to obtain dicyandiamide tail gas with the temperature of 460 ℃ after purification and decomposition, and preheating the mixture of the dicyandiamide tail gas and the water in the tail gas heat exchanger to obtain the dicyandiamide tail gas with the temperature of 250 ℃.
The proportion of each component in the tail gas before purification and the proportion of each component after purification by taking melamine as raw material
| Before purification (%) | After purification (%) | |
| NH3 | 45 | 49 |
| CO2 | 52 | 51 |
| Melamine gas | 1 | — |
| Cyanamide | 1 | — |
| Others | 1 | — |
As can be seen from the above table, the method has a good purification effect on dicyandiamide tail gas.
Example 2
A method for purifying and decomposing dicyandiamide tail gas, which has the same steps as embodiment 1, except that: the mixture of dicyandiamide tail gas and water preheated to 350 ℃ enters a tail gas heater and is further heated to 460 ℃ by electric heating. The cleaning effect of this example is close to that of example 1.
Example 3
A method for purifying and decomposing dicyandiamide tail gas, which is the same as that in embodiment 1, except that: the dicyandiamide tail gas separated from the dicyandiamide prepared by using urea as a raw material is purified to obtain the purified dicyandiamide tail gas with the temperature of 235 ℃.
The urea is used as the raw material, the proportion of each component in the tail gas before purification and the proportion of each component after purification are as follows:
| before purification (%) | After purification (%) | |
| NH3 | 45 | 47 |
| CO2 | 52 | 53 |
| Isocyanic acid and cyanuric acid | 1 | — |
| Cyanamide | 1 | — |
| Others | 1 | — |
As can be seen from the above table, the method has a good purification effect on dicyandiamide tail gas.
Example 4
A method for purifying and decomposing dicyandiamide exhaust gas, which is the same as that in embodiment 3 and is different from that in the following point: the mixture of dicyandiamide tail gas and water preheated to 350 ℃ enters a tail gas heater to be further heated to 460 ℃ by electric heating.
The purification effect of this example is close to that of example 3.
The energy consumption for the purification treatment of dicyandiamide exhaust gas in examples 1 to 4 is listed below:
energy consumption per ton of dicyandiamide tail gas and required natural gas or electricity consumption
| Energy consumption/KJ | Consumption of | |
| Example 1 | 210902 | Natural gas 10.5Nm3 |
| Example 2 | 210902 | Electricity 58.6Kw |
| Example 3 | 196237 | Natural gas 10Nm3 |
| Example 4 | 196237 | Electricity 54.5Kw |
Although the present invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
Claims (10)
1. A method for purifying and decomposing dicyandiamide tail gas is characterized by comprising the following steps: the method comprises a production process of dicyandiamide by taking melamine or urea as a raw material, and a process of purifying and decomposing dicyandiamide tail gas through heat exchange, heating, purification and decomposition to obtain purified dicyandiamide tail gas.
2. The method for purifying and decomposing dicyandiamide tail gas according to claim 1, wherein the dicyandiamide production process comprises the steps of pyrolysis, polymerization, crystallization, separation and washing of melamine or urea to obtain dicyandiamide crystals, and the separated gas, namely dicyandiamide tail gas, is purified and decomposed.
3. The method for purifying and decomposing dicyandiamide exhaust gas according to claim 1 or 2, comprising the following steps: the dicyandiamide tail gas and water are mixed and preheated in a tail gas heat exchanger, then the mixture enters a tail gas heater for further heating, then the mixture is introduced into a purification decomposer for purification and decomposition to obtain the purified and decomposed dicyandiamide tail gas, and the purified and decomposed dicyandiamide tail gas enters a tail gas heat exchanger for preheating the mixture of the dicyandiamide tail gas and the water to obtain the purified dicyandiamide tail gas.
4. The method for purifying and decomposing dicyandiamide tail gas according to any one of claims 1 to 3, characterized in that: the temperature of the dicyandiamide tail gas is 50-300 ℃, and the pressure is 0-1 MPa.
5. The method for purifying and decomposing dicyandiamide tail gas according to claim 3, characterized in that: the water is water vapor, and the mass ratio of the dicyandiamide tail gas to the water vapor is 10-1000: 1.
6. The method for purifying and decomposing dicyandiamide exhaust gas according to claim 3, characterized in that: the preheating temperature of the mixture of the dicyandiamide tail gas and the water is 300-400 ℃.
7. The method for purifying and decomposing dicyandiamide tail gas according to claim 3, characterized in that: after preheating the dicyandiamide tail gas, further heating the dicyandiamide tail gas in a tail gas heater at the temperature of 350-550 ℃, wherein the heating mode comprises flue gas heating and/or electric heating.
8. The method for purifying and decomposing dicyandiamide tail gas according to claim 3, characterized in that: the purification decomposer is a fixed bed reactor.
9. The method for purifying and decomposing dicyandiamide exhaust gas according to claim 3, characterized in that: the temperature of the purification decomposition is 350-550 ℃; the temperature of the dicyandiamide tail gas after purification and decomposition is 350-550 ℃.
10. The method for purifying and decomposing dicyandiamide exhaust gas according to claim 3, characterized in that: after the mixture of the dicyandiamide tail gas and the water is preheated by the dicyandiamide tail gas after purification and decomposition, the temperature is 180-300 ℃.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2468383A1 (en) * | 2010-12-22 | 2012-06-27 | Evonik Degussa GmbH | Method for thermal post-combustion of waste gases from the production of acrylic acid and prussic acid |
| CN110772986A (en) * | 2019-11-29 | 2020-02-11 | 四川金象赛瑞化工股份有限公司 | Melamine tail gas purification method, melamine tail gas purification device and application thereof |
| CN113511988A (en) * | 2021-08-20 | 2021-10-19 | 四川金象赛瑞化工股份有限公司 | System and method for preparing dicyandiamide by using urea |
| CN113651728A (en) * | 2021-08-13 | 2021-11-16 | 四川金象赛瑞化工股份有限公司 | Method for transferring heat of polymerization reactor during dicyandiamide preparation |
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- 2022-04-11 CN CN202210371522.7A patent/CN114768500A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2468383A1 (en) * | 2010-12-22 | 2012-06-27 | Evonik Degussa GmbH | Method for thermal post-combustion of waste gases from the production of acrylic acid and prussic acid |
| CN110772986A (en) * | 2019-11-29 | 2020-02-11 | 四川金象赛瑞化工股份有限公司 | Melamine tail gas purification method, melamine tail gas purification device and application thereof |
| CN113651728A (en) * | 2021-08-13 | 2021-11-16 | 四川金象赛瑞化工股份有限公司 | Method for transferring heat of polymerization reactor during dicyandiamide preparation |
| CN113511988A (en) * | 2021-08-20 | 2021-10-19 | 四川金象赛瑞化工股份有限公司 | System and method for preparing dicyandiamide by using urea |
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Application publication date: 20220722 |