A kind of method by the methanol production dme
Technical field
The invention belongs to field of chemical engineering, is to be raw material with methyl alcohol, and the method through the methanol vapor phase catalytic dehydration is produced dme is specially a kind of method by the methanol production dme.
Background technology
At present, the method for using always on the market of utilizing the methanol production dme mainly is to utilize the gas phase catalysis producing dimethyl ether by dehydrating, and the reaction formula of gas phase catalysis producing dimethyl ether by dehydrating is as follows:
2CH
3OH=(CH
3)
2O+H
2O
Above-mentioned reaction is thermopositive reaction, also generates the CH of minute quantity simultaneously
4, H
2, CO, CO
2Deng by product.
The production method of existing methyl alcohol catalytic dehydration preparing dimethy ether, mainly contain the gas-phase dehydration method of Japanese Toyo Engineering Corporation and rope company of Denmark Top abroad, domestic have liquid-phase dehydration method (ZL01107996) and a vapor phase process (ZL200410022020, ZL200610079244).There is certain environmental issue in above-mentioned liquid phase method for the improvement mixed acid process, and that adopts isothermal reactor and adiabatic reactor in the vapor phase process has the cold pipe reactor of the process using that also has.
One of characteristics of existing method are to be provided with methanol distillation column, with the method for rectifying the methyl alcohol in the methanol-water mixed solution of dme rectifying Tata still are separated and purify, and the methyl alcohol after the purification returns and recycles.Two of the characteristics of existing method are directly to send into the dme rectifying tower from the reaction gas that reactor comes out after reclaiming heat, owing to reclaim the reaction gas temperature drift of heat, in order to make the dme product qualified, rectifying tower must guarantee bigger reflux ratio, make the rectifying tower tower diameter of device bigger than normal, increase the consumption and the steam consumption of recirculated cooling water simultaneously, wasted the energy.
Summary of the invention
The present invention provides the heat that can make full use of each material in the device to carry out inner heat exchange, a kind of method by the methanol production dme that the device production energy consumption is reduced just at above technical problem.
Concrete technical scheme of the present invention is as follows:
A kind of method by the methanol production dme, material benzenemethanol enters flash tank after preheating, liquid phase after flash distillation enters the vaporization of methyl alcohol vaporization tower, methyl alcohol after the vaporization mixes the back and is heated to temperature of reaction with reaction gas with flash steam, enter the reaction of Dehydration of methanol device, obtain containing dme, first alcohol and water and a small amount of non-condensable gas blended reaction gas, after heat recuperation, enter the dme rectifying tower, after separating, cat head obtains the dme product, the methanol aqueous solution that rectifying Tata still is separated enters methyl alcohol vaporization tower and carries out the methyl alcohol separation, tower still waste water discharge system after reclaiming heat of methyl alcohol vaporization tower, if the employing refined methanol is a raw material, methanol content is less than 10ppm in the waste water, and waste water can be sent to circulating water system and use as circulating water system; If adopt thick methyl alcohol, methanol content is less than 50ppm in the waste water, and waste water send Sewage treatment systems to handle.
Enter the reaction gas that obtains after the Dehydration of methanol device reaction, send into vaporization tower reboiler one after gas heat exchanger and the material benzenemethanol heat exchange that enters reactor, the tower bottoms that is used for heating methanol vaporization tower carries out heat recuperation.
Reaction gas after vaporization tower reboiler one reclaims heat is sent into rectifying tower reboiler one, and the tower bottoms that is used to heat the dme rectifying tower carries out heat recuperation.
Reaction gas after rectifying tower reboiler one reclaims heat is sent into methanol preheater two, is used for heating raw methyl alcohol and carries out heat recuperation.
Reaction gas after methanol preheater two reclaims heat is sent into the methyl ether water cooler, and the reaction gas after the recirculated water cooling is sent into gas-liquid separator, and the liquid and vapor capacity after the separation is sent into the dme rectifying tower respectively.
The steam condensate that vaporization tower reboiler two and rectifying tower reboiler two come out is sent into flash tank reboiler one and is reclaimed heat, steam condensate behind the recovery heat can directly be sent boiler systems back to, also can send into methanol preheater one again and carry out preheating material methyl alcohol, send boiler systems back to after reclaiming heat once more.
The waste water of methyl alcohol vaporization Tata still is sent into flash tank reboiler two and is reclaimed heat, and the waste water behind the recovery heat is sent system after water quench, perhaps send into methanol preheater one again and carry out sending system behind the preheating material methyl alcohol.
The dme rectifying tower enters gas cooler recirculated cooling water cooling condensation through the condensed cat head non-condensable gas of overhead condenser, the dme of condensation is directly sent as product, non-condensable gas that can't condensation is sent into the washing tower washing again, washing tower is made absorption liquid with material benzenemethanol, wash contain ether methyl alcohol and material benzenemethanol mix after enter methanol preheater one, through the washing after non-condensable gas send to torch or fuel pipe network.
From methyl alcohol vaporization tower side line extraction fusel, methanol content is 0.05% (wt) in the fusel, sends system after cooling.
If the pre-hot methanol of steam condensate can be sent the waste water behind the flash tank reboiler two recovery heats into methanol preheater one preheating material methyl alcohol again, directly send system behind the recovery heat.
A kind of method by the methanol production dme may further comprise the steps:
(1) material benzenemethanol content is 70~99.99%, part material is sent into washing tower and is made absorption liquid, the ether methyl alcohol that contains that washs mixes with the material benzenemethanol of not sending into washing tower, methyl alcohol is admitted to flash tank after the secondary preheating, flash tank is provided with two reboilers, makes the heating thermal source with steam condensate and waste water respectively;
(2) the liquid phase feed methyl alcohol after the flash distillation send into the vaporization top of tower vaporize, methanol aqueous solution in the dme rectifying tower is admitted to methyl alcohol vaporization tower middle part simultaneously, in methyl alcohol vaporization tower, separate, the isolated methanol loop of cat head is used, the isolated waste water of tower still is sent system after heat recuperation, the fusel of tower side line extraction is sent system after cooling;
(3) methanol steam that comes out of methyl alcohol vaporization column overhead is with after the isolating vapour phase of flash tank is mixed, arrive temperature of reaction through gas heat exchanger and reaction gas heat exchange, enter the reaction of Dehydration of methanol device, obtain the non-condensable gas blended reaction gas of unreacted methanol, dme, water and minute quantity, enter gas heat exchanger and reclaim heat;
(4) reaction gas that comes out from gas heat exchanger is sent into vaporization tower reboiler one and is reclaimed heat, send into rectifying tower reboiler one again and reclaim heat, in order to utilize reaction heat fully, reaction gas after three grades of heat recuperation is sent into methanol preheater two preheating material methyl alcohol again, and the reaction gas that comes out is sent into the methyl ether water cooler and is cooled to 40~125 ℃ with recirculated cooling water;
(5) cooled thick methyl ether can directly be sent into the dme rectifying tower, also can send into gas-liquid separator, be separated into vapour, enter the dme rectifying tower after the liquid two-phase more respectively, in rectifying tower, separate purification, cat head obtains the dme product, the cat head non-condensable gas that comes out from overhead condenser enters the further condensation of gas cooler, condensed dme is sent after the product dme mixes, non-condensable gas that can't condensation is sent to the washing tower washing, non-condensable gas after the washing is sent to torch or fuel pipe network, wash contain ether methyl alcohol and material benzenemethanol mix after carry out preheating.
Positively effect of the present invention is embodied in: adopt this explained hereafter dme, by refined methanol, the steam consumption of dme per ton can be dropped to by present 1.0 tons about 0.65 ton, the recirculated cooling water internal circulating load can be dropped to by present 80 tons about 55 tons, the heat of each material carried out inner exchanging during the present invention had utilized fully and installed, and the production power consumption of device is reduced, and had saved the energy, to the processing that pollutent also carries out, environmental protection.
Description of drawings
Fig. 1 for thick methyl ether among the present invention directly advance rectifying tower process flow sheet.
Fig. 2 carries out advancing respectively after the vapor-liquid separation process flow sheet of rectifying tower for thick methyl ether among the present invention.
Wherein, V1---flash tank, V2---gas-liquid separator, T1---methyl alcohol vaporization tower, T2---dme rectifying tower, T3---washing tower, R---Dehydration of methanol device, E1---gas heat exchanger, E2---vaporization tower reboiler one, E3---rectifying tower reboiler one, E4---methanol preheater two, E5---methyl ether water cooler, E6---vaporization tower reboiler two, E7---rectifying tower reboiler two, E8---flash tank reboiler one, E9---flash tank reboiler two, E10---methanol preheater one, E11---overhead condenser, E12---gas cooler, 1---contain ether methyl alcohol, 2---material benzenemethanol, 3---reaction gas, 4---dme, 5---methanol aqueous solution, 6---waste water, 7---steam condensate, 8---the cat head non-condensable gas, 9---non-condensable gas that can't condensation, 10---the non-condensable gas after the washing, 11---fusel
Embodiment
The schematic flow sheet that thick methyl ether directly advances rectifying tower among the present invention is seen Fig. 1; Thick methyl ether carries out advancing respectively after the vapor-liquid separation schematic flow sheet of rectifying tower and sees Fig. 2.
Embodiment one:
As shown in Figure 1, material benzenemethanol 2 is 10000kg/h, methyl alcohol 9950kg/h wherein, water 50kg/h, methanol content 99.5% (wt), small portion material benzenemethanol 2 is sent into washing tower T3, and washing tower T3 is a packing tower, the non-condensable gas 9 that washing can't condensation, non-condensable gas 10 after the washing is 39.6kg/h, directly send to torch or fuel pipe network, ether methyl alcohol 1 amount that contains of washing is 3855kg/h, and sends into methanol preheater one E10 vapor condensation water preheat after the raw material of not sending into washing tower T3 mixes.
Methyl alcohol vaporization tower T1 number of theoretical plate is 20, working pressure 1.0Mpa, side line extraction fusel 11, the waste water 6 of vaporization Tata still wherein methanol content is 0.008% (wt), sending into methyl alcohol vaporization tower T1 middle part from the next methanol aqueous solution 5 of dme rectifying tower T2 tower still separates, the methyl alcohol that cat head obtains enters reactor with material benzenemethanol 2, and the tower still obtains waste water 6 amounts and is 2808.8kg/h, sends to the circulation water station and do the make up water use after reclaiming heat.
Gasified methanol enters gas heat exchanger E1, arrive about 260 ℃ of temperature of reaction with the reaction gas heat exchange, enter reactor R and carry out the methanol vapor phase catalytic and dehydration reaction, reaction gas 3 temperature of coming out from Dehydration of methanol device R are about 353 ℃, reaction gas and gasified methanol are after gas heat exchanger E1 heat exchange, enter vaporization tower reboiler one E2, rectifying tower reboiler one E3, methanol preheater two E4 reclaim heat, are about 143 ℃ through level Four heat exchange afterreaction temperature degree.
Reaction gas 3 is sent into methyl ether water cooler E5 with recirculated cooling water condensation cooling, and directly sending into dme rectifying tower T2 after being cooled to 100 ℃ separates.Dme rectifying tower number of theoretical plate is 15, working pressure 0.85~0.9Mpa.Feed plate is the 8th theoretical stage, the reflux ratio of dme rectifying tower T2 is 1.1: 1, cat head extraction product dme 7151.6kg/h, purity is 99.3% (wt), 40 ℃ of temperature, the noncondensable gas 8 of cat head is sent into gas cooler E12 condensation once more, and the dme that condensation is got off is sent as product, and non-condensable gas 9 that can't condensation enters washing tower T3 washing.
The total consumption of steam of methyl alcohol vaporization tower T1 and dme rectifying tower T2 is 4450kg/h, and the recirculated cooling water internal circulating load is 393t/h.
Embodiment two:
As shown in Figure 1, purity is that 85% methanol feedstock 2 is 20000kg/h, methyl alcohol 17000kg/h wherein, water 3000kg/h, small portion is sent into washing tower T3, the ether methyl alcohol 1 that contains that washs mixes with the methanol feedstock 2 of not sending into washing tower, sends into methanol preheater one E10 waste water 6 preheatings of coming out from flash tank reboiler two E2.
Material benzenemethanol 2 after the preheating enters methanol preheater two E4, and with reaction gas 3 preheatings, the methyl alcohol after the preheating enters flash tank V1, and the liquid methanol of flash distillation is not sent into methyl alcohol vaporization tower T1 top and vaporized.
Methyl alcohol vaporization tower T1 number of theoretical plate is 25, and working pressure is 1.1Mpa.
Sending into methyl alcohol vaporization tower T1 middle part from the next methanol aqueous solution 5 of dme rectifying tower T2 tower still separates, feed plate is from the 15th theoretical stage of cat head number, the tower still obtains waste water 6 and is about 7760.0kg/h, wherein methanol content is 0.035% (wt), behind flash tank reboiler two E9 and methanol preheater one E10 recovery heat, send system, be about 86.4kg/h from methyl alcohol vaporization tower T1 middle and lower part extraction fusel 11, after the recirculated cooling water cooling, send system.
Gasified methanol enters gas heat exchanger E1, with the reaction gas heat exchange to about 270 ℃, enter reactor R and carry out the methanol vapor phase catalytic and dehydration reaction, reaction gas 3 temperature of coming out from Dehydration of methanol device R are about 360 ℃.
Enter vaporization tower reboiler one E2 with the reaction gas 3 of gasified methanol after gas heat exchanger E1 heat exchange, rectifying tower reboiler one E3, methanol preheater two E4 reclaim heat, through level Four heat exchange afterreaction temperature degree about 136 ℃.
Reaction gas 3 is sent into methyl ether water cooler E5 to be cooled off with the recirculated cooling water condensation, cooled thick methyl ether temperature is about 80 ℃, directly sending into dme rectifying tower T2 separates, cat head obtains dme 4 products, the noncondensable gas 8 of cat head is about 50.8kg/h after the condensation washing, directly send to torch or fuel pipe network.
Dme rectifying tower T2 number of theoretical plate is 18, and feed plate is that working pressure is 0.95Mpa from the 10th theoretical stage of cat head number, reflux ratio is 0.9: 1, cat head extraction product dme 12105.3kg/h, dme purity is 99.1% (wt) in the dme product, 43 ℃ of temperature.
The total consumption of steam of methyl alcohol vaporization tower T1 and dme rectifying tower T2 is 9876kg/h, and the recirculated cooling water internal circulating load is 732t/h.
Embodiment three:
As shown in Figure 2, material benzenemethanol 2 is 2000kg/h, methyl alcohol 1820kg/h wherein, water 180kg/h, methanol content 91% (wt), washing tower T3 are packing tower, ether methyl alcohol 1 amount that contains of washing is about 734.6kg/h, with send into methanol preheater one after other methanol feedstock mixes, non-condensable gas 10 amounts after the washing are 5.5kg/h, send to flare system.
Methyl alcohol vaporization tower T1 number of theoretical plate is 20, working pressure 0.9Mpa, and side line fusel 11 is from the 14th theoretical stage extraction of cat head number, and produced quantity is 9.8kg/h, and methyl alcohol vaporization tower T1 tower still waste water 6 amounts are about 683.1kg/h, and wherein methanol content is 0.05% (wt).
The number of theoretical plate of dme rectifying tower T2 is 20, working pressure 0.75Mpa, the thick ether that comes out from methyl ether water cooler E5 is cooled to 120 ℃ and enters gas-liquid separator V2, vapour phase after the separation enters dme rectifying tower T2 from the 7th theoretical stage of cat head number, liquid phase enters dme rectifying tower T2 from the 13rd of cat head number, and dme rectifying tower T2 reflux ratio is 1.6: 1, cat head extraction product dme 1301.6kg/h, purity is 99.5% (wt), 35 ℃ of temperature.
The total consumption of steam of methyl alcohol vaporization tower T1 and dme rectifying tower T2 is 995kg/h, and the recirculated cooling water internal circulating load is 89.4t/h.