CN1241900C - Method for joint production of dialkyl carbonate and diatomic alcohol - Google Patents
Method for joint production of dialkyl carbonate and diatomic alcohol Download PDFInfo
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Abstract
The present invention relates to a low-energy consumption method for the joint production of dialkyl carbonate and diatomic alcohol, which comprises the steps of the synthesis of alkenyl carbonate, the preparation of dialkyl carbonate and diatomic alcohol and the recovery of a catalyst. The method uses a petrochemical industry route, and on the basis of the prior art, a flow path and operation parameters are optimized; the total process of the synthesis of the dialkyl carbonate is used as a large system for energy coupling utilization, the requirement amount of steam for the synthesis and the joint production of the dialkyl carbonate and the diatomic alcohol is controlled to the level that a product per ton is smaller than 1.0 ton by using the reaction heat of the alkenyl carbonate and a heat pump technology. The method optimizes the production process for the joint production of the dialkyl carbonate and the diatomic alcohol, and greatly reduces energy consumption and the amount of cold water; compared with those of a production device with the same scale, steam amount is reduced by 50 to 90%, and the amount of the cold water is reduced by 40 to 60%.
Description
Technical field
The present invention relates to dialkyl carbonate (Dialkyl Carbonate, DAC), comprise methylcarbonate (Dimethyl Carbonate, DMC), diethyl carbonate (Diethyl Carbonate, DEC) etc. preparation method, relate in particular to epoxy second (third) alkane, monohydroxy-alcohol is such as methyl alcohol and ethanol etc., with greenhouse waste gas carbonic acid gas be basic raw material, the method for coproduction second (the third) the two pure and mild dialkyl carbonate.
Background technology
Dialkyl carbonate is a kind of " environmental friendliness ", broad-spectrum organic chemicals as methylcarbonate (DMC), and its toxicity is very low, deserves to be called a kind of nonpoisonous chemicla basically.It can replace methyl-sulfate (violent in toxicity) as methylating agent, with replace phosgene (violent in toxicity) as the carbonylation agent, also can be used as gasoline dope and (replace methyl tertiary butyl ether with octane value and the oxygen level that improves gasoline, MTBE), also can be used as paint solvent, such as replacement dimethylbenzene and butylacetate or ethyl ester etc., thereby has very high industrial application value.
Dialkyl carbonate has multiple synthetic method, but the method with industrialization meaning mainly contains three kinds.The one, the petrochemical complex route, it is by carbonate synthesis second (third) alkene ester, carries out transesterification reaction with alkyl alcohol then, coproduction ethylene glycol or propylene glycol are also referred to as ester-interchange method simultaneously; The 2nd, the Coal Chemical Industry route, it is to use the monobasic lower alcohol, carries out the carbonylation oxidizing reaction such as methyl alcohol and oxygen and carbon monoxide and makes, and is also referred to as the carbonylation oxidation style; The 3rd, the chemical fertilizer route, it is with urea and monobasic lower alcohol, carries out alcoholysis reaction such as methyl alcohol and makes, simultaneously ammonia gas as byproduct.
The problem that conventional art exists:
Ethylene (propylene) carbonate, comprise the synthetic of propylene carbonate (PC) or NSC 11801 (EC): the synthetic of ethylene (propylene) carbonate is a reversible reaction that thermal discharge is bigger, and catalyzer is tetraethyl-ammonium bromide (C
2H
5)
4N
+Br
-Or KI.Therefore, effective measure that improve transformation efficiency are along with the carrying out of reaction, constantly reduce temperature of reaction.Traditional method in U.S. Pat 4314945, adopts product ethylene (propylene) carbonate itself as solvent, or claims thinner, and wherein, ethylene (propylene) carbonate accounts for 85-99.6% (wt), and reactor is a plurality of adiabatic reactor series connection of intersegmental heat exchange.Because the exothermic heat of reaction amount of carbonate synthesis alkene ester is bigger, be 23kcal/mol, therefore, a device of producing 100000 tons of DMC per year, this part heat of per hour emitting is equivalent to 5 tons of steam, and, because the wider range of this reaction, between 100-200 ℃, can the by-product low-pressure steam, and in the conventional art, reaction heat does not obtain fine utilization.
Dialkyl carbonate is synthetic: the synthetic transesterification reaction that is based on ethylene (propylene) carbonate and monohydroxy-alcohol of dialkyl carbonate, catalyzer is to be dissolved in the highly basic sodium alkoxide that reacts feed liquid, belongs to homogeneous catalytic reaction, has separating and recycling problem of catalyzer and reaction mass.Although have a plurality of patents or document propose to adopt insoluble solid alkali, constituted the heterogeneous catalysis process, such as U.S. Pat 4661609 and document Applied Catalysis:A, 2001, there is not the separation problem of catalyzer in 259-266.But the speed of response of heterogeneous process can not show a candle to homogenous process.Under the homogeneous phase situation, being reflected at about 10 minutes can be near balance, and under heterogeneous situation, needs several hrs usually.Therefore, heterogeneous process can not adapt to the needs of scale operation, and homogenous process just can be realized scale operation.But a problem of homogenous process is the separation of catalyzer and recycles.
Second problem is that ethylene (propylene) carbonate and corresponding dibasic alcohol are such as propylene carbonate+propylene glycol, form azeotrope, dialkyl carbonate and corresponding monohydroxy-alcohol also form azeotrope, such as methyl alcohol and dimethyl carbonate azeotrope, exist the product separation problem of more complicated.In applicant's existing Chinese invention patent ZL94112211.5, a kind of reaction rectification technique that adopts tray column as reaction fractionating tower is disclosed, can make the rare ester of carbonic acid surpass conversion fully under the situation of measuring ratio in the raw material ratio of monohydroxy-alcohol, bottom at reaction fractionating tower, can there be ethylene (propylene) carbonate, PC/EC has eliminated the azeotrope of ethylene (propylene) carbonate and corresponding dibasic alcohol.But in original patent, the temperature of reaction of tower still is too high, is 185-190 ℃, causes the side reaction of bottom product ethylene glycol or propylene glycol easily.
Under the excessive situation of monohydroxy-alcohol raw material, the cat head of reaction fractionating tower can obtain monohydroxy-alcohol and dialkyl carbonate, and such as methylcarbonate and methanol mixture, both form azeotrope, and it separates and has a difficulty.For the methylcarbonate process, under the normal pressure, the DMC addition of methylcarbonate+methanol azeotrope is 30%, and methyl alcohol is 70% (wt), and azeotropic point is 63.8 ℃.Prior art has proposed multiple separation method.In applicant's existing Chinese invention patent ZL94112211.5, disclosing a kind of is the extraction and distillation technology of extraction solvent with the ethylene (propylene) carbonate.But the operational condition of announcing is not optimized, and the charging mole proportioning of extraction agent and azeotrope is higher, is 1-2; The reflux ratio of extractive distillation column is too big, and energy consumption is also higher.
The 3rd problem of methylcarbonate synthetic is, owing to adopted excessive monohydroxy-alcohol, the mol ratio of alcohol and ethylene (propylene) carbonate is about 10, therefore, a large amount of circulations of monohydroxy-alcohol must bring higher energy consumption, therefore, utilize coupling heat utilization technologies such as heat pump, making energy obtain recycle is highly significant for reducing production costs.
Summary of the invention
The technical issues that need to address of the present invention are the methods that disclose a kind of coproduction dialkyl carbonate and dibasic alcohol, solve the higher defective of this process energy consumption with the optimization by technological process and processing condition.
Technical conceive of the present invention is such:
Technology of the present invention belongs to the petrochemical complex route, and (as the technology of ZL94112211.5 patent disclosure) carried out the optimization of flow process and operating parameters on the basis of original technology, with propylene oxide (Propylene Oxide, PO) or oxyethane (EO) and CO
2Be raw material, with the big system of dialkyl carbonate synthetic whole process as an energy coupling utilization, by utilizing the reaction heat of ethylene (propylene) carbonate, and utilize heat pump techniques, make the steam requirement of synthesis of dialkyl carbonates and coproduction dibasic alcohol be controlled at product per ton (dialkyl carbonate and dibasic alcohol amount to) less than 1.0 tons levels.With propylene oxide (Propylene Oxide PO) is example, and its primitive reaction principle is as follows:
As a complete process, be divided into for two steps: (1) is by CO
2With PO reaction form propylene carbonate (Propylene Carbonate, PC); (2) by methyl alcohol and PC carry out transesterification reaction generate simultaneously propylene glycol (Propylene Glycol, PG) and DMC.These two reactions in fact all are the heat release reversible reactions that is subjected to equilibrium-limited, and the equilibrium constant of reaction (1) is about 1000, and reaction heat is about 23kcal/mol, and reaction (2) is about 0.01, and reaction heat is very little, is 2-3kcal/mol.
Therefore, total reaction is 1 molecule CO
2, 1 molecule propylene oxide and 2 molecule methyl alcohol generate 1 molecule DMC and 1 molecule PG, and this process has following two characteristics:
(1) atom utilization 100%, is the chemical reaction of zero release;
(2) with greenhouse waste gas CO
2Be raw material, turn waste into wealth;
Method of the present invention comprises the steps:
Synthesizing of ethylene (propylene) carbonate:
Rationally utilize reaction heat, the steam of by-product 0.4-0.6Mpa (temperature is about 150 ℃) can be used as the thermal source of the reboiler of dialkyl carbonate composite part.
Synthesizing of dialkyl carbonate:
(1) vapor form is adopted in the monohydroxy-alcohol circulation, and does not adopt liquid form.Enter the dialkyl carbonate of extracting rectifying tower bottom and the azeotrope of monohydroxy-alcohol is a steam by the reactive distillation column overhead, promptly reaction fractionating tower is a partial condensation.The product of extracting rectifying cat head and backflow are not adopted condenser all at first with the vapor form extraction.The steam of product unit alcohol is through directly delivering to the bottom of reaction fractionating tower after pressurizeing, as the reaction raw materials that recycles; The monohydroxy-alcohol steam of the part that refluxes heats up the back as the thermal source of the tower still reboiler of reaction fractionating tower through overdraft, and monohydroxy-alcohol circulation all employing heat pumps makes full use of heat;
(2) increase the monohydroxy-alcohol of reaction fractionating tower and the mol ratio of ethylene (propylene) carbonate, reduce tower still temperature, temperature is reduced in 70 ℃-90 ℃.Because reaction fractionating tower and extractive distillation column tower top temperature about 64 ℃, therefore, can adopt the way of pressurization, the vapor temperature of cat head is raise at 90-110 ℃, as the thermal source of tower still reheater.
(3) reduce the extraction agent/azeotrope mol ratio of extractive distillation column, thereby reduce the temperature of extractive distillation column still, for the reaction heat that makes full use of the ethylene (propylene) carbonate composite part is given security.Extractive distillation column still temperature is controlled at about 120～140 ℃, utilizes low-pressure steam by about 140～160 ℃ of the reaction heat by-products of ethylene (propylene) carbonate.
More than three technological improvements can significantly reduce the steam energy consumption and the refrigeration cycle water yield of this process.
The catalyzer of ethylene (propylene) carbonate and monohydroxy-alcohol transesterify generally adopts sodium alkoxide, as sodium methylate or sodium ethylate, both has been dissolved in monohydroxy-alcohol, also is dissolved in dibasic alcohol, and therefore, as long as sodium alkoxide is not converted into yellow soda ash, catalyzer can recycle for a long time.But, have minor amount of water deposit catalyzer situation under, ethylene (propylene) carbonate is easy to and sodium alkoxide reaction, becomes the yellow soda ash that is insoluble to reaction mass, causes inactivation.After the liquid elder generation evaporation concentration of the present invention with reactive distillation Tata still, catalyst concn in the solution is concentrated to 10-50% by 1-3% (wt), after monohydroxy-alcohol mixes, concentration is reduced to 0.5-5%, the process strainer is removed undissolved impurity wherein, such as yellow soda ash etc., suitably fresh makeup catalyst is kept the round-robin catalyst concn.
Method of the present invention has been optimized the production process of coproduction dialkyl carbonate and dibasic alcohol, can significantly reduce energy consumption and cooling water amount, compares with the production equipment of same scale, can reduce steam consumption 60-90%, and cooling water amount reduces 40-70%.
Description of drawings
Fig. 1 is the synthetic schemes of ethylene (propylene) carbonate.
Fig. 2 is the schema of transesterify synthesis of dialkyl carbonates and dibasic alcohol.
Fig. 3 is the schema of catalyst recovery and dibasic alcohol.
Embodiment
Referring to Fig. 1, Fig. 2 and Fig. 3, method of the present invention comprises the steps:
(1) ethylene (propylene) carbonate is synthetic:
Propylene oxide (abbreviation PO, down together) or oxyethane (being called for short EO, down together) and CO
2At first reaction in first adiabatic reactor 101, reaction product enters external heat exchanger 102, utilizing reaction heat by-product temperature is 145～160 ℃ low-pressure steam, continuous extracting rectifying Tata still reboiler after being used for, part recirculation enters first adiabatic reactor 101 then, part enters reaction in the two the first adiabatic reactors 103, the flow of interchanger 102 is 5～30 with the weight rate ratio that enters second reactor 103, preferred 10～20, be preferably in about 15, the inlet temperature of first reactor 101 is 140-160 ℃, and temperature out is 175-190 ℃, the temperature that enters second reactor is 130～145 ℃, is preferably 135～140 ℃.
Other reaction conditionss are:
The pressure P of first reactor=2～8Mpa is generally 3～6Mpa, is preferably 4～4.5Mpa.
Raw material ratio CO
2/ PO or EO=1.01-1.1 are generally 1.03-1.05 (mol ratio).
Catalyzer tetraethyl-ammonium bromide/PO or EO=0.01～1.0% is generally 0.1%～0.5% (mol ratio).
Through behind the reactive system, the total conversion rate of PO or EO is greater than 99%, even can be greater than 99.5%.
Ethylene (propylene) carbonate product by second reactor 103 comes out wherein contains unconverted CO
2With PO or EO, and the catalyzer tetraethyl-ammonium bromide, thick alkene ester be called.Thick alkene ester enters vacuum flashing jar 104, and flash tank 104 pressure are 70～120kPa, and temperature is 130～180 ℃, is preferably between 160～170 ℃, removes overweight CO
2And PO, entering negative pressure treating tower 105 then, cat head is an ethylene (propylene) carbonate, and the tower still is catalyzer and ethylene (propylene) carbonate (ethylene (propylene) carbonate is here also as the solvent of catalyst-solvent), and circulation enters first reactor 101.Owing to may produce the by product of superpolymer, influence activity of such catalysts to a certain extent, also can regularly draw sub-fraction and remove superpolymer, be i.e. catalyst regeneration.
The pressure of negative pressure treating tower 105 is 1～15kPa, generally at 5～10kPa.Between the ratio of the ethylene (propylene) carbonate amount of ethylene (propylene) carbonate quantity of reflux and extraction is controlled at 0.1～0.5 (mol ratio), generally between 0.2～0.3.Negative pressure treating tower 105 cats head and tower still temperature are more or less the same, and generally between 1～10 ℃, tower still temperature is between 140～180 ℃, and generally between 150～160 ℃, cat head is also between 150～160 ℃.
Negative pressure treating tower 105 products enter the cat head interchanger, the by-product low-pressure steam.The low-pressure steam of this part can be directly used in the primary evaporator of follow-up reactive distillation Tata still feed liquid.Therefore, the steam heat of ethylene (propylene) carbonate treating tower cat head (also can regard the heat that the ethylene (propylene) carbonate catalyst recovery consumes as) can be used for the dialkyl carbonate catalyst recovery.
Like this, the secondary steam of the reaction heat of the reactor of ethylene (propylene) carbonate composite part and treating tower can both be utilized effectively at the dialkyl carbonate composite part.
In addition, ethylene (propylene) carbonate synthetic catalyzer mainly adopts tetraethyl-ammonium bromide, and directly synthetic in ethylene (propylene) carbonate solution by three second ammoniums and monobromethane, concentration is 10-20% (wt), and temperature is 60-120 ℃.
(2) preparation of dialkyl carbonate (being called for short DAC, down together) and dibasic alcohol:
Ethylene (propylene) carbonate at first enters extractive distillation column 202 as extraction agent, will be by next monohydroxy-alcohol and the DAC azeotrope vapor removal in reaction fractionating tower 201 tops, monohydroxy-alcohol is extracted out from extractive distillation column 202 cats head, the compressed machine 204 of part compresses the thermal source of back as reaction fractionating tower 201 tower still reboilers that heat up that boost, reflux again after the condensation, circulation entered reaction fractionating tower 201 as reaction raw materials after compressed machine 204 pressurizations of part monohydroxy-alcohol heated up, reaction fractionating tower 201 cats head are partial condensation, phlegma is as phegma, it is thick DAC that uncooled steam enters extractive distillation column 202 extractive distillation columns 202 tower stills, enter diester tower 203, cat head obtains highly purified DAC, and the tower still is an ethylene (propylene) carbonate, and the tower still is extracted material out and is divided into two strands, one circulation enters extractive distillation column 202, and one is as the raw material of reaction fractionating tower 201.The material that enters extractive distillation column 202 is 2～8 with the mol ratio that enters the material of reaction fractionating tower 201;
The principal character of this step is that the azeotrope that is entered extractive distillation column 202 by reaction fractionating tower 201 is a steam; And the reflux on extractive distillation column 202 tops refluxes after the condensation more earlier with vapor form thermal source as reaction fractionating tower 201 tower still reboilers after intensification is boosted in overdraft; The product monohydroxy-alcohol is extracted out with vapor form, and circulation enters reaction fractionating tower 201 towers as reaction raw materials after heating up through pressurization again;
The temperature of reaction fractionating tower 201 tower stills is 70～80 ℃, and purpose is that the backflow steam latent heat partly that extractive distillation column 202 pushes up is warmed up to 90～100 ℃ by pressurization, as the part of reaction fractionating tower 201 reboiler thermals source.
The reaction fractionating tower overhead vapours adopts partial condensation, and uncooled steam is steam as the raw material of downstream extractive distillation column 202, can reduce the steam consumption of reaction fractionating tower 201 and the consumption of cooling circulating water like this.
Reaction fractionating tower 201 adopts tray column, and total vapour phase resistance generally is controlled between the 12-16kPa between 10-30kPa.The cat head working pressure of extractive distillation column 202 is a normal pressure, is 101-105kPa, generally between 101-102kPa.Extractive distillation column 202 also can adopt tray column, and total vapour phase resistance is between 5-15kPa, between the general 8-10kPa.Like this, the supercharging total head of cycling element alcohol is 20-25kPa.
The main operating parameters of reaction fractionating tower 201 is as follows:
The combined feed total feed mol ratio of monohydroxy-alcohol and ethylene (propylene) carbonate is between 11～13.
Catalyst recirculation amount, conversion are 100% sodium ion, and the content in reaction fractionating tower 201 in the liquid phase is 0.05～0.5% (wt).
Best and the whole fresh monohydroxy-alcohols of round-robin catalyzer, but not cycling element alcohol is mixed into reaction fractionating tower 201, the amount of fresh monohydroxy-alcohol and the mol ratio of dialkyl carbonate are 2-4.
The reflux ratio of reaction fractionating tower 201 is 0.1～0.5;
Reaction fractionating tower 201 tower still temperature are 65～90 ℃, are preferably in 70～80 ℃;
Reaction fractionating tower 201 cat head working pressures are 70～120kPa, generally between 101～105kPa.
In reaction fractionating tower 201, liquid phase stream is especially reacted and the simultaneous column plate of rectifying through every block of column plate, and the mean residence time of liquid was controlled at 0.1-20 minute, generally was controlled at 1-5 minute, was preferably in 2-3 minute.The control of the residence time is both to have guaranteed to provide competent reaction time to the transesterification reaction of synthesis of dialkyl carbonates, also will limit the speed of response of side reaction simultaneously.Side reaction mainly is the etherification reaction that dibasic alcohol and monohydroxy-alcohol carry out.
In reactive distillation 201 towers, ethylene (propylene) carbonate can transform fully.Cat head obtains the dialkyl carbonate and the monohydroxy-alcohol of azeotrope;
For extractive distillation column 202 and diester tower 203, main operating parameters is as follows:
By the higher ethylene (propylene) carbonate of purity that the ethylene (propylene) carbonate composite part comes, purity is greater than 99.9%.
The raw materials components mole ratio of extraction agent and azeotrope is 0.2～1.0, is preferably between the 0.3-0.5, the tower still temperature that can keep extractive distillation column between 120～140 ℃, the low-pressure steam of ethylene (propylene) carbonate synthesis reactor by-product easy to use.
Be recycled to reaction fractionating tower 201 after the monohydroxy-alcohol pressurization of the cat head extraction of extractive distillation column 201, pressure head is 20-30kPa, the methyl alcohol of extractive distillation column 202 trim the top of column is warmed up to 90～100 ℃ through pressurization, and pressure is between 200～300kPa, as the thermal source of reaction fractionating tower 201 Tata still reboilers;
(3) catalyst recovery and dibasic alcohol is refining:
By the next dibasic alcohol liquid product logistics of reaction fractionating tower 201 tower stills, contain monohydroxy-alcohol, dibasic alcohol and catalyzer, also contain small amounts of ether, enter flash vaporization jar 301, the feed liquid of flash vaporization jar 301 is spissated catalyst solution, and wherein catalyst concn is counted 5～30% (wt) with sodium, sends into recirculation heater 302 by recycle pump 301 parts, back into flash vaporization jar 301, another partly enters recycling catalyst preparing tank 303.In preparing tank 303, adopt the required raw material monohydroxy-alcohol of reaction fractionating tower as thinner, catalyst concn is formulated between 0.2～2% (wt).Catalyzer that circulation prepares is through strainer 304, remove undissolved solid wherein after circulation enter reaction fractionating tower 201, and replenish fresh unit alcohol sodium catalyst to keep catalyst concentration.
The process that adopts this layout and evaporated form to be particularly suitable for the present invention relates to.Because contain the alkoxide of sodium Metal 99.5 in the feed liquid that is evaporated, even can contain undissolved yellow soda ash, this form can prevent or alleviate the fouling that salting-out effect causes on the heating tube wall.
The dibasic alcohol and the monohydroxy-alcohol steam at flash vaporization jar 301 tops enter glycol products tower 305, obtain highly purified glycol products at the tower still of glycol products tower 305, also can extract out at the side line near the tower still, can prevent that color from appearring in product.
Glycol products tower 305 cats head adopt partial condensation, and discharging is a monohydroxy-alcohol steam, wherein also contains by dibasic alcohol and ether are arranged, and enters monohydroxy-alcohol recovery tower 306, and in monohydroxy-alcohol recovery tower 306, cat head obtains the very high monohydroxy-alcohol of purity, and the tower still obtains ether and dibasic alcohol.
The 306 tower still dischargings of monohydroxy-alcohol recovery tower enter ether treating tower 307, and ether treating tower 307 adopts batch fractionating, obtains the very high ether of purity.
Main operating parameters is as follows:
The pressure of vaporizer 301 is 5～30kPa, and temperature is 120～140 ℃;
The cat head working pressure of glycol products tower 305 is between 5-30kPa, generally between 15-20kPa.Tower still temperature is controlled between 130-150 ℃, is preferably between 135-140 ℃, prevents the condensation side reaction of dibasic alcohol as far as possible.
The cat head working pressure of monohydroxy-alcohol recovery tower 306 is 5～30kPa, but for the steam that makes glycol products tower 305 cats head flows directly to monohydroxy-alcohol recovery tower 306, monohydroxy-alcohol recovery tower 306 tower top pressures should be than the little 1～3kPa of glycol products tower 305 tower top pressures, and the tower still of monohydroxy-alcohol recovery tower 306 is 50～65 ℃.
The ether treating tower 307 general batch fractionatings that adopt, the cat head working pressure is 5-30kPa, takes out lower boiling monohydroxy-alcohol (generally can contain a small amount of monohydroxy-alcohol) earlier, takes out ether then, tower still residue feed liquid enters evaporating pot 301 or glycol products tower 305, reclaims dibasic alcohol.
Embodiment 1
Device with 60,000 tons of methylcarbonates of an annual coproduction and 50,000 tons of propylene glycol is an example:
Raw material: PO=87.5kmol/h, CO
2=91.85kmol/h, methyl alcohol=178.5kmol/h.
The operational condition of ethylene (propylene) carbonate part is:
The PO total conversion rate of ethylene (propylene) carbonate part is 99.64%, and the PC yield is 99.5%.
(1) amount of recycling catalyst (calculating with 100% tetraethyl-ammonium bromide) is 0.18kmol/h;
The inlet temperature of (2) first reactor R101 is 153 ℃, and pressure is 4.2MPa, and temperature out is 178 ℃, and recycle ratio is 15.7, and the heat of byproduct steam is 8.6 * 10
6KJ/h;
The inlet temperature of (3) second reactors is 137 ℃;
(4) pressure of atmospheric flashing jar is 110kPa, and temperature is 155 ℃;
(5) tower top pressure for the treatment of tower T101 is 10kPa, and 164 ℃ of tower top temperatures, reflux ratio are 0.3,167 ℃ of tower still temperature, and the heat that the tower still needs is 5.8 * 10
6KJ/h is provided for steam by outer, and the cat head available energy is 6.1 * 10
6KJ/h.
The main operational condition of dialkyl carbonate and dibasic alcohol coproduction part is:
(1) total methyl alcohol/PC=11.8 of reaction fractionating tower;
(2) reflux ratio is 0.4;
(3) tower still temperature is 75 ℃;
(4) total stage number is 45, and catalyzer, fresh methanol and PC mixture feed plate be from cat head downward the 5th, and the methanol steam feed plate that is looped back by extractive distillation column is for being made progress the 10th by the tower still;
(5) under the normal running, reaction fractionating tower does not need the thermal source of extra steam as reboiler, and its thermal source is provided by the cat head methanol steam of extractive distillation column fully;
(6) obtain the mixture of methyl alcohol and DMC at cat head, methanol content is 71% (wt), and DMC is 29% (wt), and total flux is 27.02 tons/h;
(7) obtain methyl alcohol, propylene glycol, propylene glycol monomethyl ether and mixture of catalysts at the tower still, the flow of each component is: methyl alcohol=8080kg/h, propylene glycol=6551.2kg/h, propylene glycol monomethyl ether=77.625kg/h, catalyzer sodium methylate=100kg/h;
(8) total mol ratio of the PC/ azeotrope of extractive distillation column is 0.5;
(9) the tower still temperature of extractive distillation column is 138 ℃;
(10) to be recycled to the shaft power of the methyl alcohol compressor of reaction fractionating tower be 56kW to cat head, and internal circulating load is 19.2 tons/h;
(11) the trim the top of column vapour compression is to 200kPa, and temperature is 105.8 ℃, and the shaft power that compressor needs is 78.5kW, and the quantity of methyl alcohol of compression is 9.6 tons/h, and the reflux ratio that is equivalent to extractive distillation column is 0.5;
(12) to need heat be 8.4 * 10 to the tower still reboiler of extractive distillation column
6KJ/h, and be 150 ℃ by the temperature of ethylene (propylene) carbonate synthesis reactor byproduct steam, heat is 8.6 * 10
6KJ/h all here obtains utilizing;
(13) the cat head working pressure of diester tower (being the extraction agent recovery tower) is 10kPa, and reflux ratio is 1.0, and tower still temperature is 161 ℃, and the heat that the tower still needs is 5.9 * 10
6KJ/h is provided for steam by outer;
(14) to have obtained purity be the methylcarbonate of 99.8% (wt) to diester Tata still, and mass rate is 7851kg/h, and being equivalent to annual methylcarbonate output is 62810 tons/h.
The main operational condition of catalyst recovery and PG FF:
(1) working pressure of vaporizer is 15kPa, and temperature is 132 ℃, and the heat that needs is 12.2 * 10
6KJ/h, utilizing the steam heat of the refining cat head by-product of ethylene (propylene) carbonate is 5.75 * 10
6KJ/h, surplus heat 6.45 * 10
6KJ/h is provided for steam by outer;
(2) working pressure of PG treating tower is 14kPa, and tower still temperature is 135 ℃, and the heat that needs is 2.8 * 10
6KJ/h is provided for steam by outer, and the tower still obtains the propylene glycol that purity is 99.9% (wt), and mass rate is 6538kg/h, and being equivalent to annual propylene glycol output is 52305 tons/h;
(3) the cat head working pressure of methanol distillation column is 12kPa, and tower still temperature is 65 ℃, and the heat that need provide is 2.5 * 10
6KJ/h is provided for steam by outer, and cat head obtains the methyl alcohol that purity is 99.5% (wt), and mass rate is 8080kg/h;
(4) the ether tower is a batch fractionating, can obtain the propylene glycol monomethyl ether of 77kg/h from cat head, and purity is 99.5% (wt).
Therefore, total heat that need be provided by outer confession steam be:
5.75+5.94+6.45+2.8+2.5＝23.44×10
6kJ/h，
Be equivalent to 11.2 tons of steam/h.
Because per hour ultimate production is 7851+6538=14389kg/h, therefore, the steam demand amount of product per ton is:
11.2/14.389=0.7785 ton is less than 1 ton/h.
Claims (6)
1. the method for coproduction dialkyl carbonate and dibasic alcohol comprises the preparation and the catalyst recovery of synthetic, the dialkyl carbonate and the dibasic alcohol of ethylene (propylene) carbonate it is characterized in that synthetic propylene oxide or the oxyethane and the CO of comprising of ethylene (propylene) carbonate
2Reaction and ethylene (propylene) carbonate refining, propylene oxide or oxyethane and CO
2At first reaction in first adiabatic reactor (101), reaction product enters external heat exchanger (102), the by-product low-pressure steam, and then react through second adiabatic reactor (103), the thick product of ethylene (propylene) carbonate that reaction generates enters vacuum flashing jar (104), and then enter negative pressure treating tower (105), the mol ratio of the ethylene (propylene) carbonate amount of cat head ethylene (propylene) carbonate quantity of reflux and extraction is 0.1～0.5, negative pressure treating tower (105) cat head and tower still temperature differ 1～10 ℃, negative pressure treating tower (105) overhead product enters the cat head interchanger, the by-product low-pressure steam;
The preparation of dialkyl carbonate and dibasic alcohol comprises the reactive distillation of monohydroxy-alcohol and ethylene (propylene) carbonate reaction, be the extracting rectifying of extraction agent with the ethylene (propylene) carbonate;
Monohydroxy-alcohol is extracted out from extractive distillation column (202) cat head, the compressed thermal source of back that heat up that boost of part as reaction fractionating tower (201) tower still reboiler, reflux again after the condensation, the circulation after pressurization heats up of part monohydroxy-alcohol enters reaction fractionating tower (201) as reaction raw materials, reaction fractionating tower (201) cat head is a partial condensation, phlegma is as phegma, and uncooled steam enters extractive distillation column (202);
The material that enters extractive distillation column (202) is 2～8 with the mol ratio that enters the material of reaction fractionating tower (201);
The refining of catalyst recovery and dibasic alcohol comprises the steps: by the next liquid product logistics that comprises dibasic alcohol, monohydroxy-alcohol and catalyzer of reaction fractionating tower (201) tower still, enter flash vaporization jar (301), send into recirculation heater (302) by recycle pump (301) part, back into flash vaporization jar (301), another partly enters recycling catalyst preparing tank (303), and enters reaction fractionating tower (201) after fresh monohydroxy-alcohol mixes;
The product dibasic alcohol is directly extracted out from the tower still or the bottom side line of dibasic alcohol treating tower (305), and the product extraction on tower (305) top is a steam, directly enters the monohydroxy-alcohol recovery tower;
The low-pressure steam of interchanger (102) by-product, the low-pressure steam of negative pressure treating tower (105) overhead product by-product are used for the thermal source of the vaporizer of the tower bottom reboiler of extractive distillation column and catalyst recovery as heating.
2. method according to claim 1, it is characterized in that, the unit alcohol amplitude of boosting of the cat head extraction of extractive distillation column (201) is 20-30kPa, and the methyl alcohol of extractive distillation column (202) trim the top of column is warmed up to 90～100 ℃ through pressurization, and pressure is 200～300kPa.
3. method according to claim 1 is characterized in that, the reflux ratio of reaction fractionating tower (201) is 0.1～0.5.
4. method according to claim 3 is characterized in that, reaction fractionating tower (201) tower still temperature is 65～90 ℃.
5 methods according to claim 1 is characterized in that, the raw materials components mole ratio of extraction agent and azeotrope is 0.2～1.0.
6 methods according to claim 1 is characterized in that, the tower still temperature of extractive distillation column (202) is 120-140 ℃.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200310107987 CN1241900C (en) | 2003-10-16 | 2003-10-16 | Method for joint production of dialkyl carbonate and diatomic alcohol |
| AU2003296198A AU2003296198A1 (en) | 2003-10-16 | 2003-12-19 | Combined production of dialkyl carbonate and diol |
| PCT/CN2003/001093 WO2005066110A1 (en) | 2003-10-16 | 2003-12-19 | Combined production of dialkyl carbonate and diol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200310107987 CN1241900C (en) | 2003-10-16 | 2003-10-16 | Method for joint production of dialkyl carbonate and diatomic alcohol |
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| Publication Number | Publication Date |
|---|---|
| CN1528735A CN1528735A (en) | 2004-09-15 |
| CN1241900C true CN1241900C (en) | 2006-02-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200310107987 Expired - Fee Related CN1241900C (en) | 2003-10-16 | 2003-10-16 | Method for joint production of dialkyl carbonate and diatomic alcohol |
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| Country | Link |
|---|---|
| CN (1) | CN1241900C (en) |
| AU (1) | AU2003296198A1 (en) |
| WO (1) | WO2005066110A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10131620B2 (en) | 2015-10-20 | 2018-11-20 | Chang Chun Plastics Co., Ltd. | Process for producing dimethyl carbonate |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100443462C (en) * | 2005-05-12 | 2008-12-17 | 中国石油天然气股份有限公司 | radial reactor for preparing ethylene carbonate or propylene carbonate |
| TW200740731A (en) | 2006-02-22 | 2007-11-01 | Shell Int Research | Process for the preparation of alkanediol |
| TWI383976B (en) * | 2006-02-22 | 2013-02-01 | Shell Int Research | Process for the production of dialkyl carbonate and alkanediol |
| TWI382979B (en) | 2006-02-22 | 2013-01-21 | Shell Int Research | Process for the production of alkylene carbonate and use of alkylene carbonate thus produced in the manufacture of an alkane diol and a dialkyl carbonate |
| TWI378087B (en) | 2006-02-22 | 2012-12-01 | Shell Int Research | Process for the preparation of an alkanediol and a dialkyl carbonate |
| TW200906774A (en) * | 2007-04-23 | 2009-02-16 | Shell Int Research | Process for the preparation of an 1,2-alkylene diol and a dialkylcarbonate |
| CN102432461A (en) * | 2010-09-29 | 2012-05-02 | 江苏中鼎化学有限公司 | Production method and system for distilling mono-fatty glyceride |
| CN103159586B (en) * | 2013-03-26 | 2015-04-22 | 沈阳化工大学 | Continuous extractive distillation separation method of dimethyl carbonate-methanol azeotropic mixture |
| CN103864595B (en) * | 2014-03-07 | 2015-11-25 | 中石化上海工程有限公司 | The method of acetic acid plant Energy harvesting |
| CN105367540B (en) * | 2014-08-21 | 2017-07-25 | 中国石油化工股份有限公司 | It is a kind of while preparing the method for propylene glycol monomethyl ether and propene carbonate |
| CN104761429B (en) * | 2015-02-12 | 2017-08-11 | 中国科学院过程工程研究所 | A kind of method for producing dimethyl carbonate and ethylene glycol |
| CN108976127B (en) * | 2017-06-05 | 2021-07-30 | 中国石油化工股份有限公司 | Method and system for preparing cyclohexyl acetate and separating cyclohexane and acetic acid |
| CN109675333B (en) * | 2017-10-19 | 2021-09-14 | 中国石化工程建设有限公司 | Benzene tower fractionation device and method driven by heat pump |
| CN108101739B (en) * | 2017-12-19 | 2021-04-13 | 西安近代化学研究所 | Method for continuously preparing 3,3, 3-trifluoro-1, 2-propanediol |
| CN113769427B (en) * | 2021-09-26 | 2024-05-28 | 上海交通大学 | System and method for co-producing dimethyl carbonate and dihydric alcohol |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1049212C (en) * | 1994-06-24 | 2000-02-09 | 华东理工大学 | Improved synthetic method of dialkyl carbonate |
| US6407279B1 (en) * | 1999-11-19 | 2002-06-18 | Exxonmobil Chemical Patents Inc. | Integrated process for preparing dialkyl carbonates and diols |
-
2003
- 2003-10-16 CN CN 200310107987 patent/CN1241900C/en not_active Expired - Fee Related
- 2003-12-19 AU AU2003296198A patent/AU2003296198A1/en not_active Abandoned
- 2003-12-19 WO PCT/CN2003/001093 patent/WO2005066110A1/en active Application Filing
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10131620B2 (en) | 2015-10-20 | 2018-11-20 | Chang Chun Plastics Co., Ltd. | Process for producing dimethyl carbonate |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2005066110A1 (en) | 2005-07-21 |
| CN1528735A (en) | 2004-09-15 |
| AU2003296198A1 (en) | 2005-08-12 |
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