CN102225889B - Method for preparing dimethyl ether by dehydration of methanol - Google Patents
Method for preparing dimethyl ether by dehydration of methanol Download PDFInfo
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- CN102225889B CN102225889B CN 201110127054 CN201110127054A CN102225889B CN 102225889 B CN102225889 B CN 102225889B CN 201110127054 CN201110127054 CN 201110127054 CN 201110127054 A CN201110127054 A CN 201110127054A CN 102225889 B CN102225889 B CN 102225889B
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Abstract
The invention discloses a method for preparing dimethyl ether by dehydration of methanol, belonging to the field of chemicals. The process flow for the method comprises the following steps that: (1) extraneous methanol is sent to a methanol buffer tank to mix with the methanol from the top of a methanol rectifying tower into the raw material methanol; (2) the raw material methanol enters into a methanol vaporization tank for vaporization after preheated in methanol preheaters; (3) vaporized methanol steam enters into a reactor after a thermal reaction, reaction gas after the reaction undergoes heat exchange in a charging discharging heat exchanger, a methanol heat exchanger, a methanol tower gas reboiler, and a dimethyl ether tower charging cooler sequentially and enters into a dimethyl ether tower charging stock tank for condensation into a gas phase and a liquid phase, and the gas phase and the liquid phase respectively enter into a dimethyl ether rectifying tower; (4) steam in the dimethyl ether rectifying tower enters into a dimethyl ether tower condenser from the top of the tower for condensation and flows back to the rectifying tower, dimethyl ether products are produced in side strippers through a dimethyl ether product storage tank, and waste water in the bottom of the rectifying tower is discharged after having changed heat with the raw material methanol in one methanol preheater. The beneficial effects of the invention are as follows: the process flow and the construction of the reactor used in the invention are simple and recovery of the heat of the reaction gas is more effective, enabling upsizing of equipment.
Description
Technical field
The present invention relates to the chemical reaction device technical field, specifically, is a kind of method by dimethyl ether preparation by dehydrating methyl alcohol.
Background technology
At present, by the method for dimethyl ether preparation by dehydrating methyl alcohol two kinds of liquid phase method and vapor phase processs are arranged, wherein, vapor phase process is that methanol steam is obtained dme by the molecular sieve catalyst catalytic dehydration, and what its adopted is that gas-solid catalysis adds distillation process.Getting dme by methanol gas phase dewatering preparing is the present production method of the industrial the most ripe and dme that is most widely used.
Chinese patent literature (number of patent application 201010287747.1) discloses " a kind of method by producing dimethyl ether from methanol ", it is characterized in that: methyl alcohol is introduced into the vaporization knockout tower, after removing high boiling substance and impurity, behind reactor reaction, dewatered product enters rectifying in the stuffing rectification column, obtains the dme product of different purity.
Chinese patent literature (CN 1293029C) discloses " a kind of method with producing dimethyl ether from methanol ", it is characterized in that: adopt Particular craft and the vaporization of structure to carry to heat up in a steamer tower and be combined with the dme rectifying tower, be not provided for the methanol distillation column of methyl alcohol in the separating-purifying recovery dme tower bottom of rectifying tower mixed solution.But the deficiency that they exist is the space that can further improve in addition on the link of energy-conservation and environmental protection.
Summary of the invention
The object of the invention is to, on the basis of existing technology, provide a kind of method by dimethyl ether preparation by dehydrating methyl alcohol of more energy-conservation and environmental protection.
Methanol gas phase dewatering preparing dimethy ether must experience the process of heating raw materials-reaction-cooling-separation, and wherein topmost technology is exactly how to realize the optimal utilization of heating and cooling process heat.The present invention is on the basis that takes into full account the reaction of preparing dimethyl ether from methanol by dehydration characteristics, adopt quench type reactor between three sections adiabatic sections, so that the import temperature of reaction can be lower, by two intersegmental heat exchange, after reaching optimal reaction temperature, control reaction product temperature leaves reactor.Adopt the reactor of said structure, reaction raw materials reduced the inlet feed temperature, increased the outlet material temperature, so that only just can reach temperature of reaction by heat exchange without steam heating, the cooling water amount of outlet material is descended, greatly save energy and resource.
For achieving the above object, the technical scheme taked of the present invention is:
A kind of method by dimethyl ether preparation by dehydrating methyl alcohol is characterized in that, its technical process comprises:
(1) material benzenemethanol of (methyl alcohol tank field) of coming from the outside is sent into the methyl alcohol surge tank and is consisted of methanol feedstock with methanol mixed from the methanol rectification column overhead;
(2) enter the vaporization of methyl alcohol vaporizing tank after the successively preheating through No. 1 methanol preheater, No. 2 methanol preheater and No. 3 methanol preheater of methanol feedstock;
(3) methanol steam after the vaporization is through charging effluent exchanger overheated 240～250 ℃ of temperature that are reacted to, and enters reactor from the top of reactor; One unstripped gas that passes into the methyl alcohol vaporizing tank between reactor region carries out the cold shock heat exchange; From approximately 365～370 ℃ of reactor reaction gas temperature out, be 120～125 ℃ through temperature after charging effluent exchanger, No. 3 heat exchange of methanol devices, methanol column gas reboiler, the heat exchange of dme tower feed cooler and enter dme tower charging stock tank; Reaction gas is condensed into the vapour-liquid two-phase and passes into respectively the dme rectifying tower in dme tower charging stock tank;
(4) steam of dme rectifying tower cat head is back to rectifying tower after entering No. 1 dme tower condenser condenses, qualified after testing after at side line through dme product storage tank extraction dme product; The waste water of tower reactor is exported after No. 1 methanol preheater and methanol feedstock heat exchange.
The described reactor of step (3) adopts quench type reactor between three sections adiabatic sections, and its import temperature of reaction is lower, but by two intersegmental heat exchange, can control and leave reactor after the reaction product temperature reaches optimal reaction temperature.
The part light constituent of described dme tower condenser overhead extraction enters the alcohol wash tower of methyl alcohol surge tank top after the condenser cooling, by part fresh methanol recovery dme wherein, gas is discharged at cat head.
The still liquid of described dme tower bottom of rectifying tower enters methanol rectifying tower, the methanol steam of its cat head is back to rectifying tower after No. 2 dme tower condenser condenses, the methyl alcohol of qualified rear section extraction is got back to the methyl alcohol surge tank and mixed with the methanol feedstock that comes from the outside after testing.
Technical process of the present invention has comprised following system: quench type reactor, 2. methyl alcohol preheating and carburetion system, 3. dme distillation system, 4. methanol recovery system between 1. three sections thermal insulation of dimethyl ether by methanol dehydration are broken.
The difference that the present invention and correlation technique immediate with it " a kind of method by producing dimethyl ether from methanol " (Chinese patent, application number 201010287747.1) are compared is:
(1) correlation technique does not illustrate concrete which kind of type of reactor that adopts
The present invention adopt three sections thermal insulation disconnected between quench type reactor, so that the import temperature of reaction can be lower, by two intersegmental heat exchange, leave reactor after control reaction product temperature reaches optimal reaction temperature, adopted just the reactor of said structure, reduced the inlet feed temperature, increased the outlet material temperature, so that reaction raw materials only just can reach temperature of reaction by heat exchange without steam heating, the cooling water amount of outlet material is descended, greatly saved the energy and resource.
(2) flow process of correlation technique is: raw material preheating-flash tank-methyl alcohol vaporizing tower-Dehydration of methanol device-dme rectifying tower-washing tower; (flash tank Liquid Phase Methanol and rectifying tower bottoms are processed by the methyl alcohol vaporizing tower, and the methyl alcohol vaporizing tower has separating rectification tower still liquid methyl alcohol and two functions of preheating methanol feedstock);
Flow process of the present invention is: raw material preheating---flash tank---Dehydration of methanol device---methanol rectifying tower, and obviously more concise on flow process; (the methyl alcohol vaporizing tower is not set in the technical process, and dme rectifying tower bottoms is processed by methanol rectifying tower, and cat head obtains Liquid Phase Methanol and the utilization of fresh methanol raw material mixed cycle);
Consider from technological angle, correlation technique not only long flow path, equipment many (many 1 washing tower, 3 interchanger) but also equipment energy consumption increases (flash tank needs steam heating), methyl alcohol vaporizing tower particularly, owing to changed single separating methanol function, so that energy consumption greatly increases.
(3) correlation technique enters the dme rectifying tower successively from reactor reaction gas out after gas heat exchanger, vaporization tower reboiler 1, rectifying tower reboiler 1, methanol preheater 2, methyl ether water cooler heat recuperation;
Of the present invention from reactor reaction gas out successively through entering dme tower charging stock tank after charging effluent exchanger, No. 3 heat exchange of methanol devices, methanol column gas reboiler, the heat exchange of dme tower feed cooler, reaction gas is condensed into the vapour-liquid two-phase and passes into respectively the dme rectifying tower in dme tower charging stock tank;
Obvious difference is arranged between the two: the present invention adopt three sections thermal insulation disconnected between quench type reactor, so that the comparison of import temperature of reaction is than low 10～20 ℃ of technology, by two intersegmental heat exchange, leave reactor after control reaction product temperature reaches optimal reaction temperature, increased the comparison of outlet material temperature and increased by 10～15 ℃ than technology;
The present invention's raw material before entering reactor need not adopt steam heating, and the correlation technique raw material need to just can reach temperature of reaction through the steam heating of flash tank.
(4) the dme product of correlation technique ejects material by rectifying tower; Dme product of the present invention is by the rectifying tower lateral line discharging; Both equipment difference be exactly lateral line discharging at second block of plate of tower, the non-condensable gas component is still less in the dme product.
(5) the dme tower bottoms of correlation technique, flash tank liquid phase are sent into the processing of methyl alcohol vaporizing tower, the methyl alcohol vaporizing column overhead obtains vapour phase that methanol steam separates with flash tank and mixes and enter Dehydration of methanol device with the reaction gas heat exchange to temperature of reaction by gas heat exchanger and react, the present invention is that the Liquid Phase Methanol that cat head obtains is got back to the methyl alcohol surge tank and mixed with material benzenemethanol by methanol rectifying tower separation of dimethyl ether rectifying tower bottoms;
Do not separate through vapour, liquid in the dme tower bottoms that enters the methyl alcohol vaporizing tower in the correlation technique, the flash tank liquid material, increased the burden of methyl alcohol vaporizing tower.
(6) E5 enters the dme rectifying tower equally through vapour, liquid separation in the correlation technique, and the present invention separates vapour, liquid by vapour liquid separator 103, enters respectively different column plates and separates, thereby greatly saved energy consumption.
(7) in the correlation technique washing tower is set, explanation ejects from the dme rectifying tower and contains the incoagulability component the material, owing to only adopting the interchanger condensation, so that in the gas phase with the dme product, need to increase a washing tower and reclaim the dme product, this not only increases facility investment, has also increased the burden of flash tank.There are not the problems referred to above in dme product lateral line discharging of the present invention.
Description of drawings
Accompanying drawing is the process flow sheet of a kind of method by dimethyl ether preparation by dehydrating methyl alcohol of the present invention.
Embodiment
Provide the embodiment of a kind of method by dimethyl ether preparation by dehydrating methyl alcohol of the present invention below in conjunction with accompanying drawing, but should be pointed out that enforcement of the present invention is not limited to following embodiment.
A kind of method by dimethyl ether preparation by dehydrating methyl alcohol, its technical process is:
(1) will send into methyl alcohol surge tank (101) from the material benzenemethanol of extraneous (methyl alcohol tank field) and consist of methanol feedstock with methanol mixed from methanol rectifying tower (302) cat head;
(2) enter methyl alcohol vaporizing tank (102) vaporization after the successively preheating through No. 1 methanol preheater (209), No. 2 methanol preheater (210) and No. 3 methanol preheater (201) of methanol feedstock;
(3) methanol steam after the vaporization enters reactor (401) through overheated 250～260 ℃ of the temperature that are reacted to of charging effluent exchanger from reactor head; Carry out the cold shock heat exchange at intersegmental one unstripped gas that passes into methyl alcohol vaporizing tank (102) of reactor (401); Be that 320～360 ℃ reaction gas enters dme tower charging stock tank (103) after through charging effluent exchanger, No. 3 heat exchange of methanol devices (201), methanol column gas reboiler (207), dme tower feed cooler (203) heat exchange from reactor (401) temperature out; Reaction gas is condensed into the vapour-liquid two-phase and passes into respectively dme rectifying tower (301) in dme tower charging stock tank (103);
(3) methanol steam after the vaporization is through charging effluent exchanger overheated 240～250 ℃ of temperature that are reacted to, and enters reactor (401) from the top of reactor; Carry out the cold shock heat exchange at intersegmental one unstripped gas that passes into methyl alcohol vaporizing tank (102) of reactor (401); From reactor (401) temperature out be 365～370 ℃ reaction gas through charging effluent exchanger, No. 3 heat exchange of methanol devices (201), methanol column gas reboiler (207), dme tower feed cooler (203) heat exchange after temperature be 120～125 ℃ and enter dme tower charging stock tank (103); Reaction gas is condensed into the vapour-liquid two-phase and passes into respectively dme rectifying tower (301) in dme tower charging stock tank (103);
(4) steam of dme rectifying tower (301) cat head is back to rectifying tower (203) after entering No. 1 dme tower condenser (104) condensation, qualified after testing after at side line through dme product storage tank (106) extraction dme product; The waste water of tower reactor is exported after No. 1 methanol preheater and methanol feedstock heat exchange.
In addition, entered the alcohol wash tower of methyl alcohol surge tank (101) top by the part light constituent of dme tower condenser (104) top extraction after the condenser cooling, by part fresh methanol recovery dme wherein, gas is discharged at cat head.
Enter methanol rectifying tower (302) from the still liquid of dme rectifying tower (301) tower reactor, the methanol steam of its cat head is back to rectifying tower (203) after No. 2 dme tower condensers (105) condensation, the methyl alcohol of qualified rear section extraction is got back to methyl alcohol surge tank (101) and mixed with the methanol feedstock that comes from the outside after testing.
Claims (1)
1. the method by dimethyl ether preparation by dehydrating methyl alcohol is characterized in that, its technical process comprises:
(1) material benzenemethanol that comes from the outside is sent into the methyl alcohol surge tank and is consisted of methanol feedstock from the methanol mixed of methanol rectification column overhead;
(2) enter the vaporization of methyl alcohol vaporizing tank after the successively preheating through No. 1 methanol preheater, No. 2 methanol preheater and No. 3 methanol preheater of methanol feedstock;
(3) methanol steam after the vaporization is through charging effluent exchanger overheated 240～250 ℃ of temperature that are reacted to, and enters reactor from the top of reactor; One unstripped gas that passes into the methyl alcohol vaporizing tank between reactor region carries out the cold shock heat exchange; From approximately 365～370 ℃ of reactor reaction gas temperature out, be 120～125 ℃ through temperature after charging effluent exchanger, No. 3 heat exchange of methanol devices, methanol column gas reboiler, the heat exchange of dme tower feed cooler and enter dme tower charging stock tank; Reaction gas is condensed into the vapour-liquid two-phase and passes into respectively the dme rectifying tower in dme tower charging stock tank;
Described reactor adopts quench type reactor between three sections adiabatic sections, and its import temperature of reaction is lower, but by two intersegmental heat exchange, can control and leave reactor after the reaction product temperature reaches optimal reaction temperature;
(4) steam of dme rectifying tower cat head is back to rectifying tower after entering No. 1 dme tower condenser condenses, qualified after testing after at side line through dme product storage tank extraction dme product;
The part light constituent of described dme tower condenser overhead extraction enters the alcohol wash tower of methyl alcohol surge tank top after the condenser cooling, by part fresh methanol recovery dme wherein, gas is discharged at cat head;
The still liquid of described dme tower bottom of rectifying tower enters methanol rectifying tower, the methanol steam of its cat head is back to rectifying tower after No. 2 dme tower condenser condenses, the methyl alcohol of qualified rear section extraction is got back to the methyl alcohol surge tank and mixed with the methanol feedstock that comes from the outside after testing;
The waste water of tower reactor is exported after No. 1 methanol preheater and methanol feedstock heat exchange.
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| CN 201110127054 CN102225889B (en) | 2011-05-17 | 2011-05-17 | Method for preparing dimethyl ether by dehydration of methanol |
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| CN 201110127054 CN102225889B (en) | 2011-05-17 | 2011-05-17 | Method for preparing dimethyl ether by dehydration of methanol |
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| CN102225889B true CN102225889B (en) | 2013-04-03 |
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| CN103666535B (en) * | 2012-09-08 | 2015-04-29 | 湖北三宁化工股份有限公司 | Alcohol oil extraction device in dimethyl ether production system and alcohol oil extraction method |
| CN102850192B (en) * | 2012-10-11 | 2014-06-04 | 中国天辰工程有限公司 | Method for producing dimethyl ether by carrying out gas-phase dehydration on methanol |
| CN103254042B (en) * | 2013-05-24 | 2015-04-08 | 青岛理工大学 | Process for synthesizing dimethyl ether |
| CN104689764A (en) * | 2015-03-18 | 2015-06-10 | 昊华(成都)科技有限公司 | Heat insulation reactor with controllable temperature |
| CN106883101A (en) * | 2017-03-14 | 2017-06-23 | 北京理工大学 | A kind of methanol-based dimethyl ether fuel production and boiler heating system and method |
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| EP0629601A1 (en) * | 1993-06-01 | 1994-12-21 | Texaco Chemical Inc. | Method for the removal of dimethyl ether from methyl tertiary butyl ether |
| CN101125803A (en) * | 2007-08-17 | 2008-02-20 | 沈建冲 | Preparation method for dimethyl ether |
| CN101941892A (en) * | 2010-09-20 | 2011-01-12 | 四川天一科技股份有限公司 | Method for preparing dimethyl ether from methyl alcohol |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0629601A1 (en) * | 1993-06-01 | 1994-12-21 | Texaco Chemical Inc. | Method for the removal of dimethyl ether from methyl tertiary butyl ether |
| CN101125803A (en) * | 2007-08-17 | 2008-02-20 | 沈建冲 | Preparation method for dimethyl ether |
| CN101941892A (en) * | 2010-09-20 | 2011-01-12 | 四川天一科技股份有限公司 | Method for preparing dimethyl ether from methyl alcohol |
Non-Patent Citations (2)
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| 沈琛等.甲醇脱水制二甲醚内冷管式反应器数学模拟.《计算机与应用化学》.2011,第28卷(第2期),139-142. |
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