CN108727160B - Hydrolysis tail gas pressure control recovery equipment and process for producing glyphosate by alkyl ester method - Google Patents
Hydrolysis tail gas pressure control recovery equipment and process for producing glyphosate by alkyl ester method Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 62
- 239000005562 Glyphosate Substances 0.000 title claims abstract description 61
- XDDAORKBJWWYJS-UHFFFAOYSA-N glyphosate Chemical compound OC(=O)CNCP(O)(O)=O XDDAORKBJWWYJS-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 229940097068 glyphosate Drugs 0.000 title claims abstract description 61
- 230000007062 hydrolysis Effects 0.000 title claims abstract description 51
- 238000006460 hydrolysis reaction Methods 0.000 title claims abstract description 51
- 238000011084 recovery Methods 0.000 title claims abstract description 45
- 125000005907 alkyl ester group Chemical group 0.000 title claims abstract description 30
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 435
- NKDDWNXOKDWJAK-UHFFFAOYSA-N dimethoxymethane Chemical compound COCOC NKDDWNXOKDWJAK-UHFFFAOYSA-N 0.000 claims abstract description 92
- 239000000243 solution Substances 0.000 claims abstract description 43
- 238000010992 reflux Methods 0.000 claims abstract description 36
- 239000007864 aqueous solution Substances 0.000 claims abstract description 13
- 239000007789 gas Substances 0.000 claims description 135
- 239000007788 liquid Substances 0.000 claims description 39
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 claims description 38
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 33
- 238000006386 neutralization reaction Methods 0.000 claims description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- 239000000463 material Substances 0.000 claims description 17
- 239000003513 alkali Substances 0.000 claims description 15
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 13
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims description 13
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims description 13
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 11
- 239000010865 sewage Substances 0.000 claims description 4
- GBMDVOWEEQVZKZ-UHFFFAOYSA-N methanol;hydrate Chemical compound O.OC GBMDVOWEEQVZKZ-UHFFFAOYSA-N 0.000 claims description 3
- 230000003472 neutralizing effect Effects 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 9
- 239000010439 graphite Substances 0.000 abstract description 9
- 229910002804 graphite Inorganic materials 0.000 abstract description 9
- 230000005494 condensation Effects 0.000 abstract description 8
- 239000007791 liquid phase Substances 0.000 abstract description 8
- 239000002904 solvent Substances 0.000 abstract description 8
- 238000009833 condensation Methods 0.000 abstract description 7
- 238000005265 energy consumption Methods 0.000 abstract description 6
- 230000001419 dependent effect Effects 0.000 abstract description 5
- 238000002309 gasification Methods 0.000 abstract description 5
- 239000000047 product Substances 0.000 description 10
- 238000004064 recycling Methods 0.000 description 9
- 239000000543 intermediate Substances 0.000 description 7
- 229940050176 methyl chloride Drugs 0.000 description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 238000000926 separation method Methods 0.000 description 5
- 238000009835 boiling Methods 0.000 description 4
- 230000006837 decompression Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 3
- 239000012752 auxiliary agent Substances 0.000 description 3
- FOCAUTSVDIKZOP-UHFFFAOYSA-N chloroacetic acid Chemical compound OC(=O)CCl FOCAUTSVDIKZOP-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 2
- 229940106681 chloroacetic acid Drugs 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical compound OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000004471 Glycine Substances 0.000 description 1
- RRUHHJFQZXSOTJ-UHFFFAOYSA-N P(OC)(OC)OC.NCC(=O)O Chemical compound P(OC)(OC)OC.NCC(=O)O RRUHHJFQZXSOTJ-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229930040373 Paraformaldehyde Natural products 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 108010077895 Sarcosine Proteins 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- -1 alkyl phosphate Chemical compound 0.000 description 1
- 230000003115 biocidal effect Effects 0.000 description 1
- 230000004071 biological effect Effects 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 238000012691 depolymerization reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- BSIJOEMKOZVYPS-UHFFFAOYSA-N dimethoxymethane;hydrate Chemical compound O.COCOC BSIJOEMKOZVYPS-UHFFFAOYSA-N 0.000 description 1
- CZHYKKAKFWLGJO-UHFFFAOYSA-N dimethyl phosphite Chemical compound COP([O-])OC CZHYKKAKFWLGJO-UHFFFAOYSA-N 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005886 esterification reaction Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000002363 herbicidal effect Effects 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229920002866 paraformaldehyde Polymers 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- FSYKKLYZXJSNPZ-UHFFFAOYSA-N sarcosine Chemical compound C[NH2+]CC([O-])=O FSYKKLYZXJSNPZ-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/94—Use of additives, e.g. for stabilisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/48—Preparation of compounds having groups
- C07C41/58—Separation; Purification; Stabilisation; Use of additives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a glyphosate hydrolysis tail gas pressure control recovery device and a glyphosate hydrolysis tail gas pressure control recovery process produced by an alkyl ester method, wherein a glyphosate hydrolysis tail gas pretreatment system produced by the alkyl ester method is connected with a dilute methanol solution collection tank, the dilute methanol solution collection tank is connected with the upper part of a methylal rectifying tower through a pipeline, the top of the methylal rectifying tower is connected with a methylal rectifying tower reflux tank through a condenser I, and the methylal rectifying tower reflux tank is connected to a methylal finished product tank; the bottom of the methylal rectifying tower is connected with a methanol aqueous solution intermediate tank through a pipeline; the middle tank of the aqueous methanol solution is connected with a methanol rectifying tower through a pipeline, the top of the methanol rectifying tower is connected with a reflux tank of the methanol rectifying tower through a condenser III, and the reflux tank of the methanol rectifying tower is connected to a finished methanol tank. Specific process steps are also disclosed. The energy consumption of solvent recovery is reduced by means of pressure-controlled condensation and pressure-reduced gasification, the stability of hydrolysis tail gas recovery is improved, and a vulnerable graphite condenser highly dependent in the original liquid phase recovery process is not needed.
Description
Technical Field
The invention belongs to new equipment and a process for recycling glyphosate solvent produced by an alkyl ester method.
Background
Brief introduction to glyphosate process
Glyphosate is a highly effective, low-toxic, broad-spectrum, biocidal, nonselective herbicide with excellent biological properties. At present, the main production process of the glyphosate in China has two routes: alkyl ester process and iminodiacetic acid process. The foreign production process is mainly an iminodiacetic acid method of Monsanto company in the United states, and the main process for producing glyphosate in China is an alkyl ester method. The alkyl ester method is mainly glycine-dialkyl phosphite method, and there are other popular routes such as chloroacetic acid-alkyl ester method for producing glyphosate by using chloroacetic acid as starting material and glycine-trimethyl phosphite method.
Brief introduction to glyphosate hydrolysis tail gas recovery process
The main components of the hydrolysis tail gas of the alkyl ester method glyphosate synthetic solution are water, methylal, methanol, hydrogen chloride and chloromethane mixture, and the recovery process of the tail gas is called solvent recovery for short in the glyphosate industry.
The synthetic solution is a mixed solution of raw materials such as methanol, paraformaldehyde (or other formaldehyde sources), glycine (or other raw materials taking chloroacetic acid as a starting point raw material), dimethyl phosphite (or other alkyl phosphate) and the like, and the main components of the mixed solution are organic phosphorus intermediates (glyphosate precursors) such as N-methoxyalkyl ester methyl glycine and the like through depolymerization, condensation and esterification reactions.
The traditional recovery route for recovering the hydrolyzed tail gas has two types:
one is a liquid phase recovery route, namely: the main components are water, methylal, methanol, hydrogen chloride and chloromethane glyphosate hydrolysis tail gas are condensed by a multi-stage graphite condenser, noncondensable gas is recycled by a chloromethane device, water, methylal, methanol and hydrogen chloride in the tail gas are condensed and liquefied to obtain acidic diluted methanol, and neutral diluted methanol is obtained after neutralization and hydrogen chloride removal, and is a ternary mixed liquid mixed system consisting of methylal (A) -methanol (B) -water (C). Wherein A, B, C's volatility reduces in proper order, and three components adopt the two-stage tower to separate, specifically separates A, B from the top of the tower in proper order according to the order of the relative volatility size of component, and its concrete flow is: the tower top of the first-stage tower is distilled to obtain component A, the tower bottom mixed liquid is B+C, and the B+C enters the second-stage tower to be further separated into B (tower top distillate) and C (tower bottom residual liquid).
The method has the advantages of convenient operation, high dependence on a graphite condenser, poor intrinsic safety and high energy consumption: the hydrolysis tail gas of the process route is acid gas containing a large amount of hydrogen chloride, so that the process route is highly dependent on a graphite condenser. The graphite condenser is not resistant to temperature change and pressure, so that the glyphosate gas-liquid adopting the glyphosate process route is saturated by the leakage of the graphite condenser, the equipment investment is large, and the maintenance cost is high; the leakage in the condenser causes acidic substances and organic substances to enter the chilled water and circulating water system, the chilled water and the circulating water system are corroded, the chilled water has the explosion risk, the intrinsic safety degree is low, and the environmental protection pressure is high; the leakage in the condenser also causes chilled water to be strung into the dilute methanol system, increasing the dilute methanol throughput and running cost. In addition, in the process of the method, the materials undergo multiple phase changes of condensation, gasification and recondensing, so that the energy consumption is high and the method is uneconomical.
And the second is a gas phase recovery route, namely: the main components are water, methylal, methanol, hydrogen chloride and chloromethane glyphosate hydrolysis tail gas, the hydrogen chloride gas is removed through gas phase neutralization, the rest tail gas is a quaternary mixed gas mixed system consisting of methylal (A) -methanol (B) -water (C) -chloromethane (D), the quaternary mixed gas mixed system is separated through a two-stage rectifying tower and a condenser, and C, B is separated from the bottom of the tower in sequence according to the boiling point of the components, wherein the specific flow is as follows: c is separated from the bottom of the first-stage tower, and components A+B+D are separated from the top of the tower; A+B+D enters a second-stage tower to be further separated into B (tower bottom residual liquid) and A+D (tower top distillate), and A+D is condensed and separated into A (condensate) and D (noncondensable gas) through a condenser.
The method has the advantages of less phase change and low energy consumption, but has the defect of poor operation stability: firstly, the tail gas remained after the hydrogen chloride gas is removed from the hydrolyzed tail gas is a quaternary mixed liquid system consisting of methylal (A) -methanol (B) -water (C) -chloromethane (D), and compared with a liquid phase route, the material total amount is large, the material flow load is large (1.5 times of the liquid phase), and the chloromethane component proportion is large (accounting for 30 percent of the total tail gas), so that the operation of a recovery system is unstable. Particularly, under the emergency power failure condition, a large amount of methylal (A), methanol (B) and chloromethane (D) material systems are discharged and decompressed from the emergency decompression system, so that the operation stability is poor, and the potential safety hazard of environmental protection exists.
Disclosure of Invention
OBJECT OF THE INVENTION
Aiming at the problems and defects, the invention provides novel equipment and a novel process for recycling the hydrolysis tail gas of the glyphosate by an alkyl ester method, which can eliminate a vulnerable graphite condenser highly dependent in the original liquid phase recycling process and improve the recycling stability of the hydrolysis tail gas; and the energy consumption in the production process is reduced by a pressure-controlled condensation and decompression gasification technology, so that the intrinsic safety and the economical efficiency of the recovery of the glyphosate solvent are improved.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the glyphosate hydrolysis tail gas pressure-control recovery equipment produced by alkyl ester method comprises a dilute methanol solution collecting tank, a methylal rectifying tower, a methanol aqueous solution intermediate tank and a methanol rectifying tower,
the glyphosate hydrolysis tail gas pretreatment system produced by the alkyl ester method is connected with a dilute methanol solution collecting tank,
the dilute methanol solution collecting tank is connected with the upper part of the methylal rectifying tower through a pipeline, the top of the methylal rectifying tower is connected with the reflux tank of the methylal rectifying tower through a condenser I, and the reflux tank of the methylal rectifying tower is connected to the methylal finished product tank;
the bottom of the methylal rectifying tower is connected with a methanol aqueous solution intermediate tank through a pipeline;
the middle tank of the aqueous methanol solution is connected with a methanol rectifying tower through a pipeline, the top of the methanol rectifying tower is connected with a reflux tank of the methanol rectifying tower through a condenser III, and the reflux tank of the methanol rectifying tower is connected to a finished methanol tank.
The glyphosate hydrolysis tail gas pretreatment system produced by the alkyl ester method comprises a glyphosate hydrolysis tail gas tank, a liquid alkali tank and a dilute liquid alkali tank;
the glyphosate hydrolysis tail gas tank is connected with the lower part of the tail gas neutralization tower through a material conveying pipeline, and the liquid alkali tank is connected with the dilute liquid alkali tank through a material conveying pipeline and then is connected with the upper part of the tail gas neutralization tower;
the top of the tail gas neutralization tower is connected with a tail gas condenser through a first compressor, and the tail gas condenser is connected with a dilute methanol solution collecting tank;
the dilute alkali tank is connected with the dilute methanol solution collecting tank through a pipeline.
The methylal rectifying tower reflux tank is connected with the upper part of the methylal rectifying tower through a pipeline; the methanol rectifying tower reflux tank is connected with the upper part of the methanol rectifying tower through a pipeline.
The bottom of the methylal rectifying tower is connected with the first reboiler through a pipeline and then connected with the lower part of the methylal rectifying tower.
The bottom of the methanol rectifying tower is connected with the reboiler II through a pipeline and then connected with the lower part of the methanol rectifying tower;
the bottom of the methanol rectifying tower is connected to a sewage station through a pipeline.
The invention further aims to provide a glyphosate hydrolysis tail gas pressure-control recovery process produced by an alkyl ester method, wherein the glyphosate hydrolysis tail gas is a mixture of hydrogen chloride, methyl chloride, methanol, methylal and water vapor from a glyphosate hydrolysis station, and mainly comprises 40-45% of water, 25-35% of methanol, 10-15% of a small amount of methylal, 10-15% of methyl chloride and 0.1-2% of trace hydrogen chloride; in the process, 43% of detection, 30% of methanol, 13% of methylal, 13% of chloromethane and 1% of trace hydrogen chloride are contained. The method comprises the following steps:
neutralization and pressure control: neutralizing, controlling pressure and condensing the glyphosate hydrolysis tail gas, and leading condensate to a dilute methanol solution recovery tank; adding an auxiliary agent, standing and mixing for 10 seconds to 30 minutes, decomposing or overflowing organic impurities in the diluted methanol to realize removal, and conveying the diluted methanol after removing the organic impurities to a solvent recovery device to recover methanol and methylal products. The auxiliary agent comprises any one of alkaline substances or oxidizing agents, wherein the alkaline substances comprise sodium hydroxide, potassium hydroxide solids or solution, and the oxidizing agents comprise sodium hypochlorite and hydrogen peroxide; the addition amount of the auxiliary agent is 0.01 per mill to 10 percent of the total weight of the liquid in the dilute methanol collecting buffer tank.
Recovery of methylal: condensing liquid in a dilute methanol solution collecting tank, pumping the condensed liquid to the upper part of a methylal rectifying tower after throttling and decompressing, condensing gas at the top of the methylal rectifying tower through a condenser, returning one path of condensed gas to a methylal rectifying tower reflux tank, and returning the other path of condensed gas to a methylal finished product tank through a recovery pump, wherein liquid at the bottom of the methylal rectifying tower is sent to a methanol aqueous solution middle tank;
and (3) methanol recovery: the materials in the middle tank of the methanol aqueous solution are pumped into the upper part of the methanol rectifying tower through a pump, the gas at the top of the methanol rectifying tower is condensed by a condenser, one path of the gas returns to the reflux tank of the methanol rectifying tower, the other path of gas is pumped into the finished product tank of the methanol through a recovery pump, and the liquid at the bottom of the methanol rectifying tower is recovered to a dirty station.
In the neutralization and pressure control step, the glyphosate hydrolysis tail gas is neutralized by liquid alkali until the pH value is 7-14; the alkaline substances include, but are not limited to, sodium hydroxide and potassium hydroxide solids or solutions, and the pressure in the tail gas neutralization tower and the dilute methanol solution collecting tank is controlled to be in the range of 0.1-0.4MPa, and the system temperature is controlled to be in the range of 10-88 ℃.
The temperature of the bottom of the methylal rectifying tower is controlled to be 65+/-10 ℃, and the temperature of the upper part of the methylal rectifying tower is controlled to be 42+/-3 ℃.
The temperature of the bottom of the methanol rectifying tower is controlled to be 100+/-10 ℃, and the temperature of the upper part of the methanol rectifying tower is controlled to be 65+/-5 ℃.
The invention provides novel equipment and a process for recycling the hydrolysis tail gas of the glyphosate by an alkyl ester method, which eliminate a vulnerable graphite condenser which is highly dependent in the original liquid phase recycling process, avoid the industrial problem of high COD of chilled water caused by internal leakage of the condenser, simultaneously reduce the system pressure, improve the stability of the recycling of the hydrolysis tail gas, reduce the energy consumption of solvent recycling by means of pressure-controlled condensation and pressure-reduced gasification, and improve the intrinsic safety, stability and economy of the operation of the hydrolysis tail gas of the glyphosate.
Drawings
FIG. 1 is a schematic diagram of an apparatus for recovering tail gas from hydrolysis of glyphosate in accordance with the present invention, wherein 1 a tank for hydrolyzing tail gas of glyphosate, 2 a tank for liquid caustic soda, 3 a tail gas neutralization tower, 4 a first compressor, 5 a second compressor, 6 a tail gas condenser, 7 a dilute caustic tank, 8 a dilute methanol solution collection tank, 9 a methylal rectification column, 10 a reboiler, 11 a condenser, 12 a methylal rectification column reflux tank, 13 a methanol aqueous solution intermediate tank, 14 a methanol rectification column, 15 a condenser three, 16 a reboiler two, 17 a methanol rectification column reflux tank, 18 a methylal finished product tank, 19 a methanol finished product tank, and 20 a sewage station.
Detailed Description
Example 1
The glyphosate hydrolysis tail gas pressure-control recovery equipment produced by alkyl ester method comprises a dilute methanol solution collecting tank 8, a methylal rectifying tower 9, a methanol aqueous solution intermediate tank 13 and a methanol rectifying tower 14,
the glyphosate hydrolysis tail gas pretreatment system produced by the alkyl ester method is connected with a dilute methanol solution collection tank 8,
the dilute methanol solution collecting tank 8 is connected with the upper part of the methylal rectifying tower 9 through a pipeline, the top of the methylal rectifying tower 9 is connected with the methylal rectifying tower reflux tank 12 through a condenser I11, the methylal rectifying tower reflux tank 12 is connected to a methylal finished product tank 18, and the bottom of the methylal rectifying tower 9 is provided with a reboiler;
the bottom of the methylal rectifying tower 9 is connected with a methanol aqueous solution intermediate tank 13 through a pipeline;
the methanol aqueous solution intermediate tank 13 is connected with the methanol rectifying tower 14 through a pipeline, the top of the methanol rectifying tower 14 is connected with the methanol rectifying tower reflux tank 17 through a condenser III 15, the methanol rectifying tower reflux tank 17 is connected to the methanol finished product tank 19, and a reboiler is arranged at the bottom of the methanol rectifying tower 14.
The system for pretreating the glyphosate hydrolysis tail gas produced by the alkyl ester method comprises a glyphosate hydrolysis tail gas tank 1, a liquid alkali tank 2 and a tail gas neutralization tower 3;
the glyphosate hydrolysis tail gas tank 1 is connected with the lower part of the tail gas neutralization tower 3 through a material conveying pipeline, and the liquid caustic soda tank 2 is connected with the dilute liquid caustic soda tank 7 through a material conveying pipeline and then is connected with the upper part of the tail gas neutralization tower 3;
the glyphosate hydrolysis tail gas conveying pipeline is connected with the lower part of the tail gas neutralization tower. The upper part of the tail gas neutralization tower is also connected with a liquid caustic soda tank through a liquid caustic soda supplementing pipeline, and the lower part of the tail gas neutralization tower is also connected with the thin liquid caustic soda tank through a thin liquid caustic soda extracting pipeline. The dilute alkali tank is connected with the upper part of the tail gas neutralization tower through a material conveying pipeline and forms circulation through a pump.
The top of the tail gas neutralization tower 3 is connected with a tail gas condenser 6 through a first compressor 4, and the tail gas condenser 6 is connected with a dilute methanol solution collecting tank 8;
the upper part of the tail gas neutralization tower is connected with a tail gas condenser through a material conveying pipeline; and a compressor 1 and a compressor 2 are respectively arranged between the tail gas neutralization tower and the tail gas condenser and behind the tail gas condenser.
It should be understood that the off-gas condenser in the condensing system has at least one condenser, but is not limited to only one condenser. When there are several tail gas condensers, the tail gas condensers may be connected in parallel, serial or combined.
The liquid phase blanking of the tail gas condenser is sent to a dilute methanol solution collecting tank through the conveying pipeline. The upper part of the dilute methanol solution collecting tank is provided with a pressure balance pipe, and two ends of the pressure balance pipe are respectively connected with the dilute methanol solution collecting tank and an outlet of the tail gas condenser.
The tail gas sequentially passes through a tail gas neutralization tower, a No. 1 compressor, a condenser and a No. 2 compressor, and the non-condensable tail gas from the tail gas condenser and the tail gas from the dilute methanol solution collecting tank are converged and then are sent to a chloromethane recovery device through the No. 2 compressor.
The dilute caustic soda tank 7 is connected with the dilute methanol solution collecting tank 8 through a pipeline.
The methylal rectifying tower reflux tank 12 is connected with the upper part of the methylal rectifying tower 9 through a pipeline; the methanol rectifying tower reflux tank 17 is connected with the upper part of the methanol rectifying tower 14 through a pipeline.
The bottom of the methylal rectifying tower 9 is connected with a reboiler I10 through a pipeline and then connected with the lower part of the methylal rectifying tower 9.
The bottom of the methanol rectifying tower 14 is connected with the reboiler II 16 through a pipeline and then connected with the lower part of the methanol rectifying tower 14;
the bottom of the methanol rectifying column 14 is connected to a sewage station 20 via a line.
Example 2
A glyphosate hydrolysis tail gas pressure control recovery process produced by alkyl ester method comprises the following steps:
neutralization and pressure control: the mixture comprising hydrogen chloride, methyl chloride, methanol, methylal and water vapor from the glyphosate hydrolysis station and liquid alkali enter a tail gas neutralization tower to be neutralized to pH 7-11, acidic components in the tail gas are removed, then the tail gas is subjected to pressure control and enters a tail gas condenser for condensation and separation, condensate is respectively sent to a dilute methanol solution collecting tank, and non-condensable gas is sent to a methyl chloride recovery device.
The tail gas condenser, the dilute methanol solution collecting tank and the pressure balance pipe are controlled by the No. 1 and No. 2 compressors, and the system pressure at which the pressure balance pipe is positioned is 0.1-0.4MPa, which is marked as P. Specific limitations of the system are compressor 1 outlet, compressor 2 inlet, valve 1.
From the physical properties of water, methanol, methylal and chloromethane, the saturation temperature is as follows: water > methanol > methylal > chloromethane. Under a certain pressure, the temperature T of the tail gas is controlled to be gradually reduced by a condenser, and when the temperature of the tail gas is reduced below the saturation temperature of water, methanol and methylal, the water, the methanol and the methylal are respectively condensed and separated.
As the system pressure increases, the saturation temperature of the water, methanol, methylal, methyl chloride 4 materials increases, i.e. they condense at higher temperatures. Through examination, the saturation temperature data of the substances are as follows:
the specific pressure control condensation scheme is as follows:
when the control pressure of the off-gas condenser is P, the saturation temperatures of water, methanol, and methylal at the corresponding pressures are denoted as T (water saturation), T (methanol saturation), and T (methylal saturation) < T (methanol saturation) < T (water saturation) are known. When the control system temperature T satisfies: when T is less than T1 (methylal saturation), water, methanol and methylal in the tail gas are condensed, methyl chloride is not condensed, separation of the water, the methanol, the methylal and the methyl chloride in the tail gas is realized, the condensate enters a dilute methanol solution collecting tank, and the uncondensed methyl chloride tail gas is continuously sent to a methyl chloride recovery device for treatment. In the embodiment, the system pressure P1 is controlled within the range of 0.1-0.4MPa, the system temperature T1 is controlled within the range of 13-88 ℃, and specific examples are (1) the system pressure P=0.4 MPa, the system temperature is controlled within the range of 80-88 ℃ to meet the separation requirement, and (2) the system pressure P=0.2 MPa, the system temperature is controlled within the range of 10-62 ℃ to meet the separation requirement. It should be understood that when p=0.1 MPa, this is the special condition of normal pressure condensation.
Recovery of methylal: the diluted methanol in the diluted methanol solution collecting tank is throttled and decompressed and then goes to the upper part of the methylal rectifying tower, the boiling point of the material is reduced after decompression, and the material is gasified in the tower. The gas at the top of the methylal rectifying tower is condensed back to a reflux tank of the methylal rectifying tower through a condenser, liquid in the reflux tank of the methylal rectifying tower forms reflux through a reflux pump, and the other path of liquid is pumped to a methylal finished product tank through a recovery pump. The bottom liquid of the methylal rectifying tower is sent to a methanol water solution middle tank. The temperature of the bottom of the methylal rectifying tower is controlled to be 65+/-10 ℃, and the temperature of the upper part is controlled to be 42+/-3 ℃.
And (3) methanol recovery: the materials in the methanol water solution middle tank are pumped into the upper part of the methanol rectifying tower through a pump. The gas at the top of the methanol rectifying tower is condensed back to a reflux tank of the methanol rectifying tower through a condenser, liquid in the reflux tank forms reflux through a reflux pump, and the liquid is sent to a methanol finished product tank through a recovery pump. The bottom liquid of the methanol rectifying tower is collected to a dirty place. The temperature of the bottom of the secondary rectifying tower is controlled to be 100+/-10 ℃, and the temperature of the upper part of the secondary rectifying tower is controlled to be 65+/-5 ℃.
It is understood that the boiling point of materials in the methylal rectifying tower is reduced after decompression, boiling gasification and rectifying separation are realized only by self heat, and additional steam is not needed during normal operation, so that energy conservation is realized. The reboiler only supplements a small amount of raw steam when the primary start-up is performed or the system temperature is too low. Compared with the traditional process, the control system greatly reduces the unit consumption of the recovery steam of the ton glyphosate solvent by about 1.8t/t under the temperature and pressure conditions of the example 1 (the system pressure P=0.4 MPa and the control system temperature is 80-88 ℃), on the basis that the quality indexes of the methanol, the methylal water and the content reach the standards. Under the temperature and pressure conditions of the example 2 (the system pressure is 0.2MPa, and the system temperature is controlled to be 10-62 ℃), the unit consumption of the recycling steam of the ton glyphosate solvent is greatly reduced by about 1.4t/t on the basis that the quality indexes of the methanol and the methylal reach standards. The process and the equipment eliminate the vulnerable graphite condenser which is highly dependent in the original liquid phase recovery process, avoid the problem of high COD of the chilled water caused by internal leakage of the condenser, and improve the intrinsic safety.
Claims (8)
1. A glyphosate hydrolysis tail gas pressure control recovery process produced by an alkyl ester method is characterized by comprising the following steps:
neutralization and pressure control: neutralizing the glyphosate hydrolysis tail gas, controlling the pressure, condensing, feeding the condensate to a dilute methanol solution recovery tank,
neutralizing the glyphosate hydrolysis tail gas by alkali until the pH value is 7-14; meanwhile, the pressure in a tail gas neutralization tower and a dilute methanol solution collecting tank system is controlled at 0.4MPa, the system temperature is recorded at 80-88 ℃, the water in the glyphosate hydrolysis tail gas is 40-45%, the methanol is 25-35%, and the tail gas also contains a small amount of methylal 10-15%, chloromethane 10-15% and trace hydrogen chloride 0.1-2%;
recovery of methylal: condensing liquid in a dilute methanol solution collecting tank, throttling and decompressing to normal pressure, then entering the upper part of a methylal rectifying tower, condensing gas at the top of the methylal rectifying tower through a condenser, returning one path of condensed gas to a methylal rectifying tower reflux tank, returning the other path of condensed gas to a methylal finished product tank through a collecting pump, and returning liquid at the bottom of the methylal rectifying tower to a methanol aqueous solution middle tank;
and (3) methanol recovery: pumping the material in the methanol aqueous solution intermediate tank into the upper part of a methanol rectifying tower through a pump, condensing the gas at the top of the methanol rectifying tower through a condenser, returning one path of the gas to a reflux tank of the methanol rectifying tower, pumping the gas to a methanol finished product tank through a recovery pump, and recovering the liquid at the bottom of the methanol rectifying tower to a dirty station;
the glyphosate hydrolysis tail gas pressure control recovery device produced by the alkyl ester method comprises a dilute methanol solution collecting tank (8), a methylal rectifying tower (9), a methanol water solution intermediate tank (13) and a methanol rectifying tower (14), wherein a glyphosate hydrolysis tail gas pretreatment system produced by the alkyl ester method is connected with the dilute methanol solution collecting tank (8),
the dilute methanol solution collecting tank (8) is connected with the upper part of the methylal rectifying tower (9) through a pipeline, the top of the methylal rectifying tower (9) is connected with the reflux tank I (12) of the methylal rectifying tower through a condenser I (11), and the reflux tank I (12) of the methylal rectifying tower is connected to a methylal finished product tank (18);
the bottom of the methylal rectifying tower (9) is connected with a methanol aqueous solution intermediate tank (13) through a pipeline;
the methanol aqueous solution intermediate tank (13) is connected with the methanol rectifying tower (14) through a pipeline, the top of the methanol rectifying tower (14) is connected with the methanol rectifying tower reflux tank II (17) through a condenser III (15), and the methanol rectifying tower reflux tank II (17) is connected to a methanol finished product tank (19).
2. The process for pressure-controlled recovery of tail gas from hydrolysis of glyphosate produced by alkyl ester method as claimed in claim 1, wherein the temperature of the bottom of methylal rectifying tower is controlled to 65+ -10deg.C, and the temperature of the upper part is controlled to 42+ -3deg.C.
3. The process for pressure-controlled recovery of glyphosate hydrolysis tail gas produced by alkyl ester method as set forth in claim 1, wherein the temperature at the bottom of the methanol rectifying tower is controlled to be 100+ -10deg.C, and the temperature at the upper part is controlled to be 65+ -5deg.C.
4. The glyphosate hydrolysis tail gas pressure control recovery process produced by an alkyl ester method as claimed in claim 1, wherein the glyphosate hydrolysis tail gas pretreatment system produced by the alkyl ester method comprises a glyphosate hydrolysis tail gas tank (1), a liquid alkali tank (2), a tail gas neutralization tower (3) and a dilute liquid alkali tank (7);
the glyphosate hydrolysis tail gas tank (1) is connected with the lower part of the tail gas neutralization tower (3) through a pipeline, the liquid alkali tank (2) is connected with the upper part of the tail gas neutralization tower (3) through a pipeline and then connected with the dilute liquid alkali tank (7), and the bottom of the tail gas neutralization tower (3) is connected with the dilute liquid alkali tank (7) to form a circulation loop;
the dilute caustic soda tank (7) is connected with the dilute methanol solution collecting tank (8) through a pipeline.
5. The process for the controlled pressure recovery of the glyphosate hydrolysis tail gas produced by an alkyl ester method as claimed in claim 4, which is characterized in that the top of the tail gas neutralization tower (3) is connected with a tail gas condenser (6) through a first compressor (4), and the tail gas condenser (6) is connected with a dilute methanol solution collecting tank (8);
the tail gas condenser (6) is communicated with the dilute methanol solution collecting tank (8) through a balance pressure pipe to balance the pressure, the non-condensable gas of the tail gas condenser and the tail gas of the dilute methanol solution collecting tank are connected to the second compressor (5) after being converged, and the second compressor (5) is connected to the chloromethane collecting tank;
the tail gas condenser (6) is at least one, and when the tail gas condenser comprises a plurality of condensers, the condensers are connected in parallel or in series.
6. The process for recovering the hydrolysis tail gas of the glyphosate produced by the alkyl ester method as claimed in claim 1, which is characterized in that a reflux tank I (12) of the methylal rectifying tower is connected with the upper part of the methylal rectifying tower (9) through a pipeline; and a second reflux tank (17) of the methanol rectifying tower is connected with the upper part of the methanol rectifying tower (14) through a pipeline.
7. The process for pressure-controlled recovery of glyphosate hydrolysis tail gas produced by alkyl ester method as claimed in claim 1, wherein the bottom of methylal rectifying tower (9) is connected with reboiler one (10) through pipeline and then connected with the lower part of methylal rectifying tower (9).
8. The process for recovering the hydrolysis tail gas of the glyphosate produced by the alkyl ester method as claimed in claim 1, which is characterized in that the bottom of the methanol rectifying tower (14) is connected with a reboiler II (16) through a pipeline and then is connected with the lower part of the methanol rectifying tower (14);
the bottom of the methanol rectifying tower (14) is connected to a sewage station (20) through a pipeline.
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| CN110128469B (en) * | 2019-05-28 | 2021-07-13 | 内蒙古兴发科技有限公司 | Device and process for applying dimethyl phosphite byproduct hydrogen chloride to glyphosate synthesis |
| CN111068497A (en) * | 2019-12-13 | 2020-04-28 | 湖北泰盛化工有限公司 | Device and method for recovering solvent methanol in glyphosate production |
| CN111203090A (en) * | 2020-03-16 | 2020-05-29 | 浙江新安化工集团股份有限公司 | System and process for treating hydrolysis tail gas of glyphosate and phosphonated synthetic liquid |
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