CN112010756A - System and method for preventing burning explosion in methyl nitrite preparation process - Google Patents
System and method for preventing burning explosion in methyl nitrite preparation process Download PDFInfo
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- CN112010756A CN112010756A CN202010967382.0A CN202010967382A CN112010756A CN 112010756 A CN112010756 A CN 112010756A CN 202010967382 A CN202010967382 A CN 202010967382A CN 112010756 A CN112010756 A CN 112010756A
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- 238000004880 explosion Methods 0.000 title claims abstract description 47
- BLLFVUPNHCTMSV-UHFFFAOYSA-N methyl nitrite Chemical compound CON=O BLLFVUPNHCTMSV-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000007789 gas Substances 0.000 claims abstract description 173
- 238000007034 nitrosation reaction Methods 0.000 claims abstract description 132
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 82
- 239000001301 oxygen Substances 0.000 claims abstract description 62
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 62
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 61
- 239000002994 raw material Substances 0.000 claims abstract description 55
- 238000006243 chemical reaction Methods 0.000 claims abstract description 40
- 238000002156 mixing Methods 0.000 claims abstract description 34
- 239000007788 liquid Substances 0.000 claims description 99
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 60
- 229910052757 nitrogen Inorganic materials 0.000 claims description 29
- 238000000605 extraction Methods 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 230000009935 nitrosation Effects 0.000 claims description 13
- 239000011261 inert gas Substances 0.000 claims description 10
- 238000010168 coupling process Methods 0.000 claims description 8
- 238000012360 testing method Methods 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 7
- 230000008878 coupling Effects 0.000 claims description 7
- 238000005859 coupling reaction Methods 0.000 claims description 7
- 230000001174 ascending effect Effects 0.000 claims description 6
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 5
- 239000000945 filler Substances 0.000 claims description 5
- 229910001882 dioxygen Inorganic materials 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 238000010926 purge Methods 0.000 claims description 2
- 239000013589 supplement Substances 0.000 claims description 2
- OKKJLVBELUTLKV-MICDWDOJSA-N deuteriomethanol Chemical compound [2H]CO OKKJLVBELUTLKV-MICDWDOJSA-N 0.000 claims 1
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 18
- 239000003063 flame retardant Substances 0.000 description 18
- RFHIWBUKNJIBSE-KQYNXXCUSA-N 2-amino-9-[(2r,3r,4s,5r)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-7-methylpurin-9-ium-6-thiolate Chemical compound C12=NC(N)=NC([S-])=C2N(C)C=[N+]1[C@@H]1O[C@H](CO)[C@@H](O)[C@H]1O RFHIWBUKNJIBSE-KQYNXXCUSA-N 0.000 description 14
- 238000002485 combustion reaction Methods 0.000 description 13
- 239000012528 membrane Substances 0.000 description 10
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 238000003466 welding Methods 0.000 description 4
- LOMVENUNSWAXEN-UHFFFAOYSA-N Methyl oxalate Chemical compound COC(=O)C(=O)OC LOMVENUNSWAXEN-UHFFFAOYSA-N 0.000 description 3
- 238000007664 blowing Methods 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 2
- 230000002146 bilateral effect Effects 0.000 description 2
- 239000011195 cermet Substances 0.000 description 2
- 238000012824 chemical production Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000005984 hydrogenation reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000001902 propagating effect Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
- C07C201/04—Preparation of esters of nitrous acid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/10—Mixing gases with gases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/21—Measuring
- B01F35/211—Measuring of the operational parameters
- B01F35/2113—Pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/21—Measuring
- B01F35/211—Measuring of the operational parameters
- B01F35/2115—Temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/22—Control or regulation
- B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
- B01F35/2215—Temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/71—Feed mechanisms
- B01F35/717—Feed mechanisms characterised by the means for feeding the components to the mixer
- B01F35/71805—Feed mechanisms characterised by the means for feeding the components to the mixer using valves, gates, orifices or openings
- B01F35/718051—Feed mechanisms characterised by the means for feeding the components to the mixer using valves, gates, orifices or openings being adjustable
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/30—Driving arrangements; Transmissions; Couplings; Brakes
- B01F2035/35—Use of other general mechanical engineering elements in mixing devices
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a system and a method for preventing burning explosion in a methyl nitrite preparation process, wherein the system comprises a safe mixing subsystem and a nitrosation reaction tower, the upper part of the nitrosation reaction tower is provided with a methanol inlet (6), the lower part of the nitrosation reaction tower is provided with a reaction raw material gas inlet (9), and the safe mixing subsystem is connected with the raw material gas inlet (9). Compared with the prior art, the invention has the advantages of higher safety, capability of ensuring that oxygen and NO circulating gas can be safely, quickly and fully mixed, stable temperature in the nitrosation reaction tower and the like.
Description
Technical Field
The invention relates to the technical field of chemical production, in particular to a system and a method for preventing burning explosion in a methyl nitrite preparation process.
Background
The technical route for producing the ethylene glycol by the gas phase reaction of the synthesis gas has good economy and competitiveness. The process mainly comprises three steps of nitrosation, coupling and hydrogenation: the first step of nitrosation is to take nitric oxide, oxygen and methanol as raw materials to generate Methyl Nitrite (MN); the second step of coupling takes carbon monoxide and MN as raw materials to generate dimethyl oxalate (DMO); the third step of hydrogenation takes hydrogen and DMO as raw materials to generate ethylene glycol. Patent CN 101190884B discloses a process for conducting the nitrosation and coupling processes in nitrosation and coupling reactors, and is commonly used in the industry. Patent CN 101190884B describes a nitrosation mechanism and a form of nitrosation reactor, and the nitrosation reaction process requires mixing the DMO-removed gaseous product stream (hereinafter referred to as NO recycle gas) from the coupling reactor with oxygen, but does not specify the manner of introducing oxygen as the nitrosation reaction raw material.
In industrial nitrosation reaction, pure oxygen is usually used as a raw material, the reaction belongs to a strong exothermic reaction, and meanwhile, a reaction system contains combustible components such as CO, methanol and the like. In order to prevent the combustion and explosion problems in large-scale tower equipment for nitrosation reaction, the industry has two attempts as follows: a gas phase pre-reactor is arranged, the nitrosation reaction raw material gas consumes partial oxygen and then is introduced into a reaction tower, but a strongly exothermic pre-reaction system is difficult to control the temperature in a partition wall heat exchange mode, and a region with higher oxygen concentration is easy to generate temperature runaway and damage equipment; the nitrosation reaction raw material gas and liquid methanol are introduced in parallel flow from the top of the tower to improve the concentration of methanol at the inlet and consume oxygen as soon as possible, and the other starting point of the design is that the harm of burning and explosion at the top of the tower is far lower than that at the bottom of the tower, but the gas-liquid raw materials in parallel flow are not easy to mix, the temperature runaway caused by strong exothermic reaction is easy to occur in a gas phase area with higher oxygen concentration at the top of the tower, and in addition, considerable moisture is contained in the gas product extracted from the bottom of the tower, so that the hydrolysis of the subsequent.
The reaction of combustion requires three requirements: a combustible; an oxygen combustion improver; the source of fire or the ignition temperature. The nitrosation reaction system contains combustible CO, methanol and other components, even if the stream does not exceed the ignition point temperature (463.9 ℃ for methanol and 610 ℃ for CO), the ignition point can be triggered in an aerobic area by factors such as sparks, static electricity, lightning strike or friction impact, and the combustion reaction in an area with high oxygen concentration can be more violent and even can explode.
Notably, the region where the significant combustion phenomenon occurs needs to have the Minimum Oxygen Concentration (MOC) for propagating the flame, with reference to the MOC value of nitrogen as an inert component: the minimum oxygen concentration of CO is 5.5% (volume percentage, the same below), the minimum oxygen concentration of other organic combustible components is higher, such as 10% methanol, and the oxygen concentration of the mixed nitrosation reaction raw material gas is below 3% and decreases as the nitrosation reaction proceeds, so that the mixed raw material gas does not have flame propagation conditions when entering the reaction tower. The gas-liquid countercurrent contact in the nitrosation reaction tower proposed in patent CN 101190884B has enough and uniformly distributed liquid methanol sprayed in the gas raw material inlet area with strong heat release at the bottom of the tower, local point high temperature caused by reaction heat release or other factors can be eliminated by means of liquid evaporation, the temperature in the reaction area can be effectively controlled near the bubble point temperature of the liquid and is far lower than the burning point of each combustible component, and therefore, the tower does not have the condition of flame.
In the chemical production process, the nitrosation reaction raw material gas is formed by mixing oxygen with NO circulating gas from a coupling reactor, the temperature of the NO circulating gas from the coupling reactor is 40-65 ℃, and the main components of the NO circulating gas are 50-70% of nitrogen, 10-20% of NO, 10-20% of methanol and 5-10% of CO. The mixing region of oxygen and NO recycle gas is of great concern for potential combustion explosion problems. The time for the NO recycle gas feed stream to pass through the mixing zone is short, given that NO is formed in the first step of the nitrosation reaction2The reaction speed of (2) is relatively slow, and the possibility that the temperature of a mixing area is greatly increased to the ignition point temperature due to reaction heat release does not exist in the process. However, it cannot be completely excluded that static electricity and sparks are generated in the mixing area due to external accidental factors, so that a combustion point occurs locally with high oxygen concentration, and flame is spread along the mixing contact surface of combustible and oxygen. Meanwhile, the concentrations of CO and methanol in the industrial NO circulating gas raw material can be close to or exceed the lower limit value of the explosion limit (12.5 percent of CO and 6.7 percent of methanol), and the possibility of explosion cannot be eliminated after combustion occurs.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a system and a method for preventing explosion in the preparation process of methyl nitrite, which reasonably apply gas mixing and explosion prevention and control technology to ensure that oxygen and NO circulating gas can be safely, quickly and fully mixed; meanwhile, the temperature in the nitrosation reaction tower is controlled to be close to the bubble point temperature of liquid, so that the possibility of violent temperature rise in the tower caused by heat release of the nitrosation reaction is eliminated.
The purpose of the invention can be realized by the following technical scheme: the system for preventing burning explosion in the preparation process of methyl nitrite comprises a safe mixing subsystem and a nitrosation reaction tower, wherein the upper part of the nitrosation reaction tower is provided with a methanol inlet, the lower part of the nitrosation reaction tower is provided with a reaction raw material gas inlet, and the safe mixing subsystem is connected with the raw material gas inlet.
The safe mixing subsystem comprises a front flame arrester, a mixer and a rear flame arrester which are sequentially connected, wherein the mixer is connected with an oxygen gas source, the front flame arrester is connected with NO circulating gas, and the rear flame arrester is connected with a feed gas inlet. And the NO circulating gas enters a mixer through a front flame arrester to be mixed with oxygen to obtain reaction raw material gas, and the reaction raw material gas flows through a rear flame arrester and enters a nitrosation reaction tower through a nitrosation reaction raw material gas inlet.
The safe mixing subsystem is also provided with an inert gas channel which comprises a nitrogen channel and a steam channel, wherein the nitrogen channel is provided with a second valve which can feed nitrogen into the mixer, and the steam channel is provided with a third valve which can feed steam into the mixer; the nitrogen and the water vapor can be used as purge gas when the vehicle is started or stopped, and when the temperature of the mixer exceeds 50 ℃ of the normal working condition or the pressure exceeds 1.5 times of the normal working condition, the second valve and/or the third valve are opened, the nitrogen and the water vapor are used as double-insurance fire extinguishing inert gas, and the condensate water of the steam does not influence the fire extinguishing and cooling functions.
The mixer is connected with a safety valve, the safety valve is also connected with the depressurization containing tank, and when strong pressure waves occur in the mixer, namely the pressure reaches 2 times of the operating pressure, the pressure is automatically relieved to avoid explosion; the mixer is also provided with a rupture disk as a substitute or supplement measure of a safety valve, and when strong pressure waves occur in the mixer, namely the pressure exceeds the operating pressure by 3 times, the pressure is automatically released to avoid explosion; the safety valve and the rupture membrane form an anti-explosion double-insurance measure of the mixer.
The front flame arrester adopts a slit type flame-retardant flame arrester, the maximum test safety clearance value is 0.5-1 mm, and the passing resistance of NO circulating gas under normal working conditions is 0.2-2 kPa; the rear flame arrester adopts a gap type explosion-proof flame arrester, a metal ceramic explosion-proof flame arrester or a filler type explosion-proof flame arrester, the maximum test safety clearance value is 0.1-0.5 mm, and the flow resistance is 0.5-5 kPa under the normal working condition.
The front flame arrester is used for preventing the flame which possibly occurs in the mixer from reversely spreading to the upstream of the flow, and a filler type flame arrester is not used so as to prevent filler or fragments from being blown into the mixer; the rear flame arrester is used for preventing flame which possibly occurs in the mixer from propagating downstream into the nitrosation reaction tower, and has an auxiliary effect on the full mixing of oxygen and NO circulating gas.
The front flame arrester or/and the rear flame arrester adopt/adopts the series connection and matching of flame-retardant layers with different maximum test safety clearance values, so that the flow resistance is reduced while the flame-retardant effect is ensured.
The mixer, the front flame arrester and the rear flame arrester are all cylindrical; the front flame arrester, the rear flame arrester and the gas pipeline are connected into a whole in a flange or welding mode; the front flame arrester, the rear flame arrester and the mixer are connected into a whole in a flange or welding mode. The mixer, the front flame arrester and the rear flame arrester are in sizes meeting the requirements of gas mixing, flame arresting speed and interconnection, and the time of passing the nitrosation reaction raw gas through the safe mixing subsystem is 0.1-1 second under normal working conditions.
Furthermore, an oxygen distributor is installed in the mixer and comprises a central main pipe and at least two branch pipes, the central main pipe is vertically communicated with the branch pipes, the branch pipes are symmetrically arranged on two sides of the central main pipe, small holes symmetrically distributed by taking the central main pipe as the center are formed in the branch pipes, and the direction of air flow in the small holes is consistent with the flow direction of NO circulating gas in the mixer.
Furthermore, a first valve is arranged between the mixer and the oxygen gas source, oxygen is introduced into the central main pipe of the oxygen distributor through the first valve and flows out through the small holes of the branch pipes to be mixed with the NO circulating gas, the first valve is interlocked with the temperature and pressure control in the mixer, and when the temperature of the mixer exceeds 50 ℃ of the normal working condition or the pressure of the mixer exceeds 1.5 times of the normal working condition, the first valve is automatically closed.
The top of the nitrosation reaction tower is also provided with a gas outlet which is connected with a gas cooler; the bottom of the nitrosation reaction tower is also provided with a CO inlet and a liquid extraction outlet, the liquid extraction outlet is returned and connected with the nitrosation reaction tower through a circulating pipeline, and the circulating pipeline is provided with a circulating pump.
The nitrosation reaction raw material gas inlet is positioned above the liquid level of the bottom kettle of the nitrosation reaction tower; the CO inlet is positioned below the liquid level of the bottom kettle of the nitrosation reaction tower.
The method for preventing burning explosion in the preparation process of methyl nitrite by adopting the system comprises the following steps: and fully mixing the circulating NO gas and oxygen through a safe mixing subsystem to serve as reaction raw material gas, feeding the reaction raw material gas into a nitrosation reaction tower from the bottom, introducing cooling condensate and supplementary liquid methanol from a liquid inlet at the top of the nitrosation reaction tower, carrying out countercurrent contact with ascending gas flow in the nitrosation reaction tower, carrying out nitrosation reaction to generate methyl nitrite, extracting residual methanol and water generated by the nitrosation reaction from a liquid extraction port at the bottom of the nitrosation reaction tower, and returning the extracted liquid to the nitrosation reaction tower through a circulating pump circulating part tower bottom.
Further, the reaction raw material gas is introduced from a nitrosation reaction raw material gas inlet above the liquid level of the bottom kettle of the nitrosation reaction tower, and supplementary CO gas is introduced from a CO inlet below the liquid level of the bottom kettle of the nitrosation reaction tower; monitoring the temperature above the liquid level of the tower kettle, circulating part of the tower bottom produced liquid to the nitrosation reaction tower through a circulating pump when the temperature is 5-15 ℃ higher than the bubble point temperature of the liquid in the tower kettle, supplementing the total amount of the liquid in the area so as to ensure that the reaction heat release above the liquid level of the tower kettle is more sufficient than that in the concentrated area, continuously spraying the liquid, controlling the gas phase temperature through liquid vaporization, and allowing the rest part of the tower bottom produced liquid to enter a liquid treatment device.
The space in the tower near the reaction raw material gas inlet is a region with concentrated heat release of the nitrosation reaction, and the supplemented CO gas is introduced from the lower part of the liquid level of the bottom kettle of the nitrosation reaction tower, so that the content of methyl nitrite in the liquid in the bottom kettle of the tower is reduced, the gas-liquid two-phase full mixing heat and mass transfer at the bottom of the tower is facilitated, and the temperature of the gas-liquid two-phase is close to the equilibrium temperature.
In the preparation process of methyl nitrite, the temperature and the pressure of a mixing area where oxygen enters and a reaction area with higher oxygen concentration can be controlled within a safe range by the invention, thereby ensuring the safe operation of a system.
Compared with the prior art, the invention has the following advantages:
1. pre-mixing NO circulating gas and oxygen in a safe mixing subsystem to ensure that the oxygen content in the reaction feed gas entering the nitrosation reaction tower does not have the condition of flame propagation, thereby preventing combustion explosion and ensuring the safety in the preparation process of methyl nitrite;
2. the front flame arrester and the rear flame arrester are respectively arranged at the front and the rear of the mixer, so that flame which possibly appears in the mixer is prevented from flowing upwards and downwards, and the safety of the NO circulating gas and oxygen during mixing is improved;
3. the rapid and sufficient mixing and safety of NO circulating gas and oxygen are ensured through the arrangement of an oxygen distributor, double-insurance fire extinguishing inert gas and an electromagnetic valve, when the temperature or pressure of the mixer is abnormal, the first valve is automatically closed to cut off the oxygen source, and the second valve and/or the third valve are opened to introduce inert gas nitrogen and/or water vapor to prevent combustion reaction in the mixer;
4. the mixer is provided with a safety valve and a rupture membrane to form an anti-explosion double-insurance measure, and when strong pressure waves occur in the mixer, the pressure is automatically released, so that possible combustion and explosion are controlled within a lower harm range, and the safety is further improved;
5. part of tower bottom produced liquid is circulated by a circulating pump, the temperature in the nitrosation reaction tower is controlled to be close to the bubble point temperature of the liquid, the possibility of violent temperature rise in the tower caused by heat release of the nitrosation reaction is eliminated, the condition that flame does not appear in the nitrosation reaction tower is ensured, the occurrence of combustion explosion can be prevented, and the safety in the preparation process of methyl nitrite is further ensured.
Drawings
FIG. 1 is a schematic view of a system for preventing explosion during the production of methyl nitrite according to the present invention;
in the figure: 1-mixer, 2-front flame arrester, 3-rear flame arrester, 4-safety valve, 5-rupture membrane, 6-liquid inlet, 7-gas outlet, 8-gas cooler, 9-nitrosation reaction raw material gas inlet, 10-CO inlet, 11-liquid extraction outlet, 12-circulating pump, 13-first valve, 14-second valve, 15-third valve, 16-depressurization holding tank, a-NO circulating gas, b-oxygen, c-reaction raw material gas, d-methanol, e-residual methanol and water generated by nitrosation reaction, f-part bottom extraction liquid, j-residual bottom extraction liquid, g-nitrogen, h-steam, i-nitrosation gas product and k-CO gas.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation processes are given, but the scope of the invention is not limited to the following examples.
Example 1
As shown in fig. 1, a system for preventing combustion and explosion in a methyl nitrite production process comprises a mixer 1, a front flame arrester 2, a rear flame arrester 3, a safety valve 4, a rupture membrane 5, a liquid inlet 6, a gas outlet 7, a gas cooler 8, a nitrosation reaction raw material gas inlet 9, a CO inlet 10, a liquid extraction outlet 11, a circulation pump 12, a first valve 13, a second valve 14, a third valve 15 and a depressurization storage tank 16.
NO cycle gas a (temperature 60 ℃, pressure 5bar, volume flow 55000m3The main components of the mixed gas are 60 percent of nitrogen, 18 percent of NO, 12 percent of methanol, 7 percent of CO and the like), the mixed gas enters a mixer 1 through a front flame arrester 2 and is mixed with oxygen b entering the mixer 1 through an oxygen distributor, and the oxygen b (the temperature is 25 ℃, the pressure is 5bar, and the volume flow is 1200 m)3H) through the first valveThe door 13 enters a central main pipe of the oxygen distributor in the mixer 1, then enters 11 branch pipes which are communicated with the central main pipe in the vertical direction of the central main pipe, enters the mixer 1 from small holes on the branch pipes, and is uniformly mixed with the NO circulating gas a, and the direction of the small holes is consistent with the flowing direction of the NO circulating gas a in the mixer 1; the center distance of the branch pipes is 9 percent of the length of the central main pipe, the diameter of the small holes on the branch pipes is 6mm, and the distance between the small holes is 80 mm.
The front flame arrester 2 adopts a slit type flame-retardant type flame arrester, the maximum test safety clearance (MESG) value is 0.6mm, the flame-retardant speed is 3m/s, the thickness of a flame-retardant layer is 1000mm, and the passing resistance of NO circulating gas a under normal working conditions is 450 Pa; the rear flame arrester 3 is also a gap type flame arrester, two flame-retardant layers are connected in series and matched, the flame-retardant speed is 15m/s, the maximum test safety clearance (MESG) value of the flame-retardant layer close to the mixer 1 is 0.6mm, the thickness of the flame-retardant layer is 1000mm, the maximum test safety clearance (MESG) value of the flame-retardant layer close to the entrance of the nitrosation tower is 0.2mm, the thickness of the flame-retardant layer is 500mm, and the flow resistance under the normal working condition is 2300 Pa; the front flame arrester 2, the mixer 1 and the rear flame arrester 3 all adopt cylinder pipelines with the diameter of 1600mm, and the volumes of the mixer 1 and the rear flame arrester 3 are 3m3(ii) a The residence time of the oxygen b in the mixer and the rear flame arrester 3 is 0.46 seconds;
oxygen b is introduced into the first valve 13 to be interlocked with the temperature and pressure control in the mixer 1, and when the temperature of the mixer 1 reaches more than 150 ℃ or is impacted by strong pressure waves of more than 10bar in the mixer 1, the first valve 13 is automatically closed; the first valve 13 is connected with the second valve 14 and the third valve 15 in parallel to respectively introduce nitrogen and water vapor, when the temperature of the mixer 1 exceeds 150 ℃ or is impacted by strong pressure waves above 10bar in the mixer, the automatic control system automatically opens the second valve 14 and the third valve 15, and respectively introduces nitrogen and water vapor as double-insurance fire extinguishing inert gas.
A safety valve 4 is arranged close to the outer part of the wall surface of the mixer 1 and is connected to a depressurization containing tank 16 through a thick pipeline, and the safety valve 4 is arranged to automatically release pressure when being impacted by strong pressure waves above 15bar in the mixer so as to avoid explosion; as a supplementary measure of the safety valve 4, a rupture membrane 5 is arranged at the same time near the outer side of the wall of the mixer, and the pressure is automatically released to avoid explosion when the rupture membrane is impacted by a strong pressure wave of more than 25bar in the mixer; the safety valve and the rupture membrane form an anti-explosion double-insurance measure of the mixer.
Feeding nitrosation reaction raw material gas c into a nitrosation reaction tower from the liquid level of the tower bottom, extracting gas flow from the top of the nitrosation reaction tower after reaction, feeding the gas flow into a gas cooler 8 to be cooled to 45 ℃, feeding liquid methanol d (the temperature is 40 ℃, the mass flow is 40 tons/h) and cooling condensate (the temperature is 45 ℃, the mass flow is 30 tons/h) into the nitrosation reaction tower from the top of the nitrosation reaction tower, carrying out countercurrent contact with ascending gas flow in the tower, generating nitrosation reaction to generate methyl nitrite, feeding CO gas k (the temperature is 25 ℃, the pressure is 5.5bar, and the volume flow is 4500m3H) introducing the residual methanol and water e generated by the nitrosation reaction into the tower from the bottom of the nitrosation reaction tower from the liquid level of the tower kettle (the temperature is 67 ℃, and the mass flow is 36 tons/h); when the temperature above the liquid level of the monitoring tower kettle exceeds 75 ℃, part of liquid f is circulated through a circulating pump 12 (with the rated flow of 25 tons/h), and the total amount of sprayed liquid at the bottom of the tower is supplemented, so that the gas phase temperature is controlled through liquid vaporization.
Example 2
A system for preventing burning explosion in the preparation process of methyl nitrite comprises a mixer 1, a front flame arrester 2, a rear flame arrester 3, a safety valve 4, a rupture membrane 5, a liquid inlet 6, a gas outlet 7, a gas cooler 8, a nitrosation reaction raw material gas inlet 9, a CO inlet 10, a liquid extraction outlet 11, a circulating pump 12, a first valve 13, a second valve 14, a third valve 15 and a depressurization accommodating tank 16.
A liquid inlet 6 and a gas outlet 7 are arranged at the top of the nitrosation reaction tower, and the gas outlet 7 is connected with a gas cooler 8; a nitrosation reaction raw material gas inlet 9, a CO inlet 10 and a liquid extraction outlet 11 are arranged at the bottom of the nitrosation reaction tower, the liquid extraction outlet 11 is returned and connected with the nitrosation reaction tower through a circulating pipeline, and the circulating pipeline is provided with a circulating pump 12.
Leading spark arrester 2 adopts slot formula flame retardant type spark arrester, adopts two-layer back-fire relief layer to establish ties, and the maximum experimental safe clearance (MESG) value of the back-fire relief layer that is close to NO circulation gas a entry is 0.5mm, and the MESG that is close to the back-fire relief layer of blender 1 is 0.8mm, and the back-fire relief speed is 0.1 times of intraductal airspeed, NO circulation gas a's resistance 1kPa that passes through under the normal operating mode, rearmounted spark arrester 3 adopts cermet flame retardant type spark arrester, and MESG is 0.1mm, and the back-fire relief speed is 2 times of intraductal airspeed, flow resistance 5kPa under the normal operating mode. The mixer 1, the front flame arrester 2 and the rear flame arrester 3 are all cylindrical, the flame arresters are connected with the gas pipeline and the mixer 1 and the flame arresters into a whole through flanges, and the time of passing the nitrosation reaction feed gas c through the safe mixing subsystem is 1 second under normal working conditions.
An oxygen distributor is arranged in the mixer 1 and comprises a central main pipe and two branch pipes, the central main pipe is vertically communicated with the branch pipes, the branch pipes are symmetrically arranged on two sides of the central main pipe, small holes which are symmetrically distributed by taking the central main pipe as a center are formed in the branch pipes, and the direction of air flow in the small holes is consistent with the flow direction of NO circulating gas a in the mixer 1.
A first valve 13 is arranged between the mixer 1 and the oxygen source, oxygen b is introduced into a central main pipe of the oxygen distributor through the first valve 13 and flows out through small holes of the branch pipes to be mixed with NO circulating gas a, the first valve 13 is interlocked with temperature and pressure control in the mixer 1, and when the temperature of the mixer 1 exceeds 50 ℃ under a normal working condition or the pressure of the mixer 1 exceeds 1.5 times under the normal working condition, the first valve 13 is automatically closed. The mixer 1 is also connected with an inert gas channel which comprises a nitrogen channel and a steam channel, the nitrogen channel is provided with a second valve 14, nitrogen g can be introduced into the mixer 1, the steam channel is provided with a third valve 15, steam h can be introduced into the mixer 1, the nitrogen g and the steam h are used as blowing gas when the mixer is started and stopped, and the second valve 14 or the third valve 15 is opened when the temperature of the mixer 1 exceeds 50 ℃ of the normal working condition or the pressure of the mixer exceeds 1.5 times of the normal working condition.
The mixer 1 is close to wall department installation relief valve 4, and relief valve 4 is connected to the holding tank 16 that steps down with thick pipeline, and automatic pressure release is in order to avoid the explosion when 1 internal pressure of mixer reaches operating pressure 2 times, and rupture disk 5 is still installed to 1 wall of mixer, and automatic pressure release is in order to avoid the explosion when 1 internal pressure of mixer reaches operating pressure 3 times.
The method for preventing the burning explosion in the preparation process of the methyl nitrite by adopting the system of the embodiment comprises the following steps: NO circulating gas a enters a mixer 1 through a preposed flame arrester 2 to be mixed with oxygen b to obtain reaction raw material gas c, the reaction raw material gas c flows through a postposition flame arrester 3 and enters a nitrosation reaction tower through a nitrosation reaction raw material gas inlet 9, the reaction raw material gas c enters from the upper part of a liquid level, supplemented CO gas k enters from the lower part of the liquid level, gas flow after reaction is extracted from a gas outlet 7 at the top of the nitrosation reaction tower and then enters a gas cooler 8 to be cooled, the cooled gas serves as a nitrosation gas product i, cooling condensate and supplemented liquid methanol d enter from a liquid inlet 6 at the top of the nitrosation reaction tower and is in countercurrent contact with ascending gas flow in the nitrosation reaction tower, nitrosation reaction is carried out to generate methyl nitrite, residual methanol and water generated by the nitrosation reaction are extracted from a liquid outlet 11 at the bottom of the liquid level at the bottom of the nitrosation reaction tower, the temperature above the nitrosation reaction tower is monitored, and when the temperature is 5 ℃ higher than the liquid And in the tower, the rest part of tower bottom produced liquid j enters a liquid treatment device.
Example 3
A system for preventing burning explosion in the preparation process of methyl nitrite comprises a mixer 1, a front flame arrester 2, a rear flame arrester 3, a safety valve 4, a rupture membrane 5, a liquid inlet 6, a gas outlet 7, a gas cooler 8, a nitrosation reaction raw material gas inlet 9, a CO inlet 10, a liquid extraction outlet 11, a circulating pump 12, a first valve 13, a second valve 14, a third valve 15 and a depressurization accommodating tank 16.
A liquid inlet 6 and a gas outlet 7 are arranged at the top of the nitrosation reaction tower, and the gas outlet 7 is connected with a gas cooler 8; a nitrosation reaction raw material gas inlet 9, a CO inlet 10 and a liquid extraction outlet 11 are arranged at the bottom of the nitrosation reaction tower, the liquid extraction outlet 11 is returned and connected with the nitrosation reaction tower through a circulating pipeline, and the circulating pipeline is provided with a circulating pump 12.
Leading spark arrester 2 adopts slot type flame retardant type spark arrester, adopts two-layer back-fire relief layer to establish ties, the biggest experimental safe clearance (MESG) value of the back-fire relief layer that is close to NO circulation gas a entry is 0.8mm, the MESG that is close to the back-fire relief layer of blender 1 is 1mm, back-fire relief speed is 0.6 times of intraductal airspeed, NO circulation gas a's resistance 1kPa that passes through under the normal operating mode, rearmounted spark arrester 3 adopts filler type flame retardant type spark arrester, adopt two-layer back-fire relief layer to establish ties, the MESG that is close to the back-fire relief layer of blender 1 is 0.5mm, the MESG that is close to the back-fire relief layer of nitrosation tower entry is 0.8mm, back-fire relief speed is 1 times of intraductal airspeed, flow resistance 2 kPa. The mixer 1, the front flame arrester 2 and the rear flame arrester 3 are all cylindrical, the flame arresters and the gas pipeline as well as the mixer 1 and the flame arresters are connected into a whole in a welding mode, and the time of passing the nitrosation reaction feed gas c through the safe mixing subsystem is 0.1 second under normal working conditions.
Install the oxygen distributor in the blender 1, the oxygen distributor includes central house steward and eight branch pipes, and central house steward communicates with the branch pipe is perpendicular, and the branch pipe sets up at central house steward bilateral symmetry, is provided with the aperture that uses central house steward to distribute as central symmetry on the branch pipe, and the air current direction in the aperture is unanimous with the interior NO circulation gas a flow direction of blender 1.
A first valve 13 is arranged between the mixer 1 and the oxygen source, oxygen b is introduced into a central main pipe of the oxygen distributor through the first valve 13 and flows out through small holes of the branch pipes to be mixed with NO circulating gas a, the first valve 13 is interlocked with temperature and pressure control in the mixer 1, and when the temperature of the mixer 1 exceeds 200 ℃ under a normal working condition or the pressure of the mixer 1 exceeds 3 times under the normal working condition, the first valve 13 is automatically closed. The mixer 1 is also connected with an inert gas channel which comprises a nitrogen channel and a steam channel, the nitrogen channel is provided with a second valve 14, nitrogen g can be introduced into the mixer 1, the steam channel is provided with a third valve 15, steam h can be introduced into the mixer 1, the nitrogen g and the steam h are used as blowing gas when the mixer is started and stopped, and the second valve 14 and the third valve 15 are opened when the temperature of the mixer 1 exceeds 200 ℃ under the normal working condition or the pressure of the mixer exceeds 3 times under the normal working condition.
The mixer 1 is close to wall department installation relief valve 4, and relief valve 4 is connected to the holding tank 16 that steps down with thick pipeline, and automatic pressure release is in order to avoid the explosion when 1 internal pressure of mixer reaches operating pressure 5 times, and rupture disk 5 is still installed to 1 wall of mixer, and automatic pressure release is in order to avoid the explosion when 1 internal pressure of mixer reaches operating pressure 10 times.
The method for preventing the burning explosion in the preparation process of the methyl nitrite by adopting the system of the embodiment comprises the following steps: NO circulating gas a enters a mixer 1 through a preposed flame arrester 2 to be mixed with oxygen b to obtain reaction raw material gas c, the reaction raw material gas c flows through a postposition flame arrester 3 and enters a nitrosation reaction tower through a nitrosation reaction raw material gas inlet 9, the reaction raw material gas c enters from the upper part of a liquid level, supplemented CO gas k enters from the lower part of the liquid level, gas flow after reaction is extracted from a gas outlet 7 at the top of the nitrosation reaction tower and then enters a gas cooler 8 to be cooled, the cooled gas serves as a nitrosation gas product i, cooling condensate and supplemented liquid methanol d enter from a liquid inlet 6 at the top of the nitrosation reaction tower and is in countercurrent contact with ascending gas flow in the nitrosation reaction tower, nitrosation reaction is carried out to generate methyl nitrite, residual methanol and water generated by the nitrosation reaction are extracted from a liquid outlet 11 at the bottom of the liquid level at the bottom of the nitrosation reaction tower, the temperature above the nitrosation reaction tower is monitored, and when the temperature is 10 ℃ higher than the liquid And in the tower, the rest part of tower bottom produced liquid j enters a liquid treatment device.
Example 4
A system for preventing burning explosion in the preparation process of methyl nitrite comprises a mixer 1, a front flame arrester 2, a rear flame arrester 3, a safety valve 4, a rupture membrane 5, a liquid inlet 6, a gas outlet 7, a gas cooler 8, a nitrosation reaction raw material gas inlet 9, a CO inlet 10, a liquid extraction outlet 11, a circulating pump 12, a first valve 13, a second valve 14, a third valve 15 and a depressurization accommodating tank 16.
A liquid inlet 6 and a gas outlet 7 are arranged at the top of the nitrosation reaction tower, and the gas outlet 7 is connected with a gas cooler 8; a nitrosation reaction raw material gas inlet 9, a CO inlet 10 and a liquid extraction outlet 11 are arranged at the bottom of the nitrosation reaction tower, the liquid extraction outlet 11 is returned and connected with the nitrosation reaction tower through a circulating pipeline, and the circulating pipeline is provided with a circulating pump 12.
Leading spark arrester 2 adopts slit formula flame retardant type spark arrester, adopts two-layer back-fire relief layer to establish ties, the biggest experimental safe clearance (MESG) value of the back-fire relief layer that is close to NO circulation gas a entry is 0.5mm, the MESG that is close to the back-fire relief layer of blender 1 is 0.6mm, fire retardance speed is 0.3 times of intraductal airspeed, NO circulation gas a's resistance 1kPa that passes through under the normal operating mode, rearmounted spark arrester 3 adopts cermet flame retardant type flame arrester, adopt two-layer back-fire relief layer to establish ties, the MESG that is close to the back-fire relief layer of blender 1 is 0.1mm, the MESG that is close to the back-fire relief layer of nitrosation tower entry is 0.5mm, the fire retardance speed is 1.5 times of intraductal airspeed, flow resistance 3kPa under the normal operating mode. The mixer 1, the front flame arrester 2 and the rear flame arrester 3 are all cylindrical, the flame arresters and the gas pipeline as well as the mixer 1 and the flame arresters are connected into a whole in a welding mode, and the time of passing the nitrosation reaction feed gas c through the safe mixing subsystem is 0.5 second under normal working conditions.
Install the oxygen distributor in the blender 1, the oxygen distributor includes central house steward and eight branch pipes, and central house steward communicates with the branch pipe is perpendicular, and the branch pipe sets up at central house steward bilateral symmetry, is provided with the aperture that uses central house steward to distribute as central symmetry on the branch pipe, and the air current direction in the aperture is unanimous with the interior NO circulation gas a flow direction of blender 1.
A first valve 13 is arranged between the mixer 1 and the oxygen source, oxygen b is introduced into a central main pipe of the oxygen distributor through the first valve 13 and flows out through small holes of the branch pipes to be mixed with NO circulating gas a, the first valve 13 is interlocked with temperature and pressure control in the mixer 1, and when the temperature of the mixer 1 exceeds 100 ℃ under a normal working condition or the pressure of the mixer 1 exceeds 2 times under the normal working condition, the first valve 13 is automatically closed. The mixer 1 is also connected with an inert gas channel which comprises a nitrogen channel and a steam channel, the nitrogen channel is provided with a second valve 14, nitrogen g can be introduced into the mixer 1, the steam channel is provided with a third valve 15, steam h can be introduced into the mixer 1, the nitrogen g and the steam h are used as blowing gas when the mixer is started and stopped, and the second valve 14 and the third valve 15 are opened when the temperature of the mixer 1 exceeds the normal working condition by 100 ℃ or the pressure of the mixer exceeds the normal working condition by 2 times.
The mixer 1 is close to wall department installation relief valve 4, and relief valve 4 is connected to the holding tank 16 that steps down with thick pipeline, and automatic pressure release is in order to avoid the explosion when 1 internal pressure of mixer reaches operating pressure 3 times, and rupture disk 5 is still installed to 1 wall of mixer, and automatic pressure release is in order to avoid the explosion when 1 internal pressure of mixer reaches operating pressure 6 times.
The method for preventing the burning explosion in the preparation process of the methyl nitrite by adopting the system of the embodiment comprises the following steps: NO circulating gas a enters a mixer 1 through a preposed flame arrester 2 to be mixed with oxygen b to obtain reaction raw material gas c, the reaction raw material gas c flows through a postposition flame arrester 3 and enters a nitrosation reaction tower through a nitrosation reaction raw material gas inlet 9, the reaction raw material gas c enters from the upper part of a liquid level, supplemented CO gas k enters from the lower part of the liquid level, gas flow after reaction is extracted from a gas outlet 7 at the top of the nitrosation reaction tower and then enters a gas cooler 8 to be cooled, the cooled gas serves as a nitrosation gas product i, cooling condensate and supplemented liquid methanol d enter from a liquid inlet 6 at the top of the nitrosation reaction tower and is in countercurrent contact with ascending gas flow in the nitrosation reaction tower, nitrosation reaction is carried out to generate methyl nitrite, residual methanol and water generated by the nitrosation reaction are extracted from a liquid outlet 11 at the bottom of the liquid level at the bottom of the nitrosation reaction tower, the temperature above the nitrosation reaction tower is monitored, and when the temperature is 15 ℃ higher than the liquid And in the tower, the rest part of tower bottom produced liquid j enters a liquid treatment device.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (10)
1. The system for preventing the burning explosion in the preparation process of the methyl nitrite is characterized by comprising a safe mixing subsystem and a nitrosation reaction tower, wherein the upper part of the nitrosation reaction tower is provided with a methanol inlet (6), the lower part of the nitrosation reaction tower is provided with a reaction raw material gas inlet (9), and the safe mixing subsystem is connected with the raw material gas inlet (9).
2. The system for preventing burning explosion in the preparation process of methyl nitrite according to claim 1, wherein the safety mixing subsystem comprises a front flame arrester (2), a mixer (1) and a rear flame arrester (3) which are connected in sequence, wherein the mixer (1) is connected with an oxygen gas source, the front flame arrester (2) is connected with NO circulating gas, and the rear flame arrester (3) is connected with the raw material gas inlet (9).
3. The system for preventing burning explosion in the preparation process of methyl nitrite according to claim 1 or 2, wherein the safe mixing subsystem is also provided with an inert gas channel which comprises a nitrogen channel and a water vapor channel, the nitrogen channel is provided with a second valve (14), nitrogen (g) is introduced into the mixer (1), the water vapor channel is provided with a third valve (15), and water vapor (h) is introduced into the mixer (1); the nitrogen (g) and the water vapor (h) are used as purge gases during start and stop, and when the temperature of the mixer (1) exceeds the normal working condition by 50 ℃ or the pressure exceeds the normal working condition by 1.5 times, the second valve (14) and/or the third valve (15) are/is opened, and the nitrogen (g) and the water vapor (h) are used as double-insurance fire extinguishing inert gases.
4. The system for preventing the burning explosion in the preparation process of the methyl nitrite according to the claim 2, characterized in that the mixer (1) is connected with a safety valve (4), the safety valve (4) is connected with a depressurization containing tank (16), and the pressure is automatically relieved when the pressure of the mixer (1) exceeds the operating pressure by 2.0 times; the mixer (1) is also provided with a rupture disk (5), and when the pressure of the mixer (1) exceeds the operating pressure by 3 times, the pressure is automatically released.
5. The system for preventing the burning explosion in the preparation process of the methyl nitrite as claimed in claim 2, characterized in that the front flame arrester (2) adopts a slit type flame arrester for the flame arrester, the maximum test safety clearance value is 0.5-1 mm, and the passing resistance of the NO circulating gas (a) under the normal working condition is 0.2-2 kPa; the rear flame arrester (3) adopts a slit type explosion-proof flame arrester, a metal ceramic explosion-proof flame arrester or a filler type explosion-proof flame arrester, the maximum test safety clearance value is 0.1-0.5 mm, and the flow resistance under the normal working condition is 0.5-5 kPa.
6. The system for preventing burning explosion in the preparation process of methyl nitrite according to claim 2, wherein an oxygen distributor is arranged in the mixer (1), the oxygen distributor comprises a central main pipe and at least two branch pipes, the central main pipe is vertically communicated with the branch pipes, the branch pipes are symmetrically arranged on two sides of the central main pipe, and the branch pipes are provided with small holes symmetrically distributed by taking the central main pipe as the center.
7. The system for preventing the burning explosion in the preparation process of the methyl nitrite according to claim 6, wherein a first valve (13) is arranged between the mixer (1) and an oxygen gas source, oxygen (b) is introduced into a central main pipe of an oxygen distributor through the first valve (13) and flows out through small holes of branch pipes to be mixed with the NO circulating gas (a), the first valve (13) is interlocked with the temperature and pressure control in the mixer (1), and when the temperature of the mixer (1) exceeds the normal working condition by 50 ℃ or the pressure of the mixer (1) exceeds the normal working condition by 1.5 times, the first valve (13) is automatically closed.
8. The system for preventing the burning explosion in the preparation process of the methyl nitrite according to the claim 1, wherein a gas outlet (7) is arranged at the top of the nitrosation reaction tower, the gas outlet (7) is connected with a gas cooler (8), a CO inlet (10) and a liquid extraction outlet (11) are arranged at the bottom of the nitrosation reaction tower, the liquid extraction outlet (11) is connected with the nitrosation reaction tower in a return mode through a circulating pipeline, and a circulating pump (12) is arranged on the circulating pipeline.
9. A method for preventing explosion during the preparation of methyl nitrite by using the system of claim 1, which comprises the following steps: and (b) fully mixing NO recycle gas (a) and oxygen (b) from a coupling reactor through a safe mixing subsystem to serve as reaction raw material gas (c), feeding the reaction raw material gas (c) into a nitrosation reaction tower from the bottom, introducing cooling condensate and supplementary liquid methanol (d) from a liquid inlet (6) at the top of the nitrosation reaction tower, carrying out countercurrent contact with ascending gas flow in the nitrosation reaction tower, carrying out nitrosation reaction to generate methyl nitrite, extracting residual methanol and water (e) generated by the nitrosation reaction from a liquid extraction outlet (11) at the bottom of the nitrosation reaction tower, and circulating part of tower bottom extraction liquid (f) to return into the nitrosation reaction tower through a circulating pump (12).
10. The method for preventing the explosion during the production of methyl nitrite according to claim 9, wherein the reaction raw material gas (c) is introduced from a nitrosation raw material gas inlet (9) above the liquid level in the bottom kettle of the nitrosation reaction tower, and the supplementary CO gas (k) is introduced from a CO inlet (10) below the liquid level in the bottom kettle; monitoring the temperature above the liquid level of the tower kettle, and when the temperature is 5-15 ℃ higher than the bubble point temperature of the liquid in the tower kettle, circulating part of the tower bottom produced liquid (f) by a circulating pump (12) to supplement the total amount of the liquid in the area.
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| CN114653170A (en) * | 2020-12-22 | 2022-06-24 | 中国石油化工股份有限公司 | Method and device for safe operation of tail gas absorption tower and application thereof |
| CN115228384A (en) * | 2022-09-23 | 2022-10-25 | 山东海科新源材料科技股份有限公司 | Methyl nitrite synthesis device and method |
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