CN115109084A - Energy-saving method for separating crude monomer - Google Patents
Energy-saving method for separating crude monomer Download PDFInfo
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- CN115109084A CN115109084A CN202210784589.3A CN202210784589A CN115109084A CN 115109084 A CN115109084 A CN 115109084A CN 202210784589 A CN202210784589 A CN 202210784589A CN 115109084 A CN115109084 A CN 115109084A
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- 238000000034 method Methods 0.000 title claims abstract description 98
- 239000000178 monomer Substances 0.000 title claims abstract description 71
- 238000010992 reflux Methods 0.000 claims abstract description 133
- 239000000463 material Substances 0.000 claims abstract description 112
- 238000009835 boiling Methods 0.000 claims abstract description 40
- LIKFHECYJZWXFJ-UHFFFAOYSA-N dimethyldichlorosilane Chemical compound C[Si](C)(Cl)Cl LIKFHECYJZWXFJ-UHFFFAOYSA-N 0.000 claims abstract description 27
- JLUFWMXJHAVVNN-UHFFFAOYSA-N methyltrichlorosilane Chemical compound C[Si](Cl)(Cl)Cl JLUFWMXJHAVVNN-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000000926 separation method Methods 0.000 claims abstract description 20
- 230000008878 coupling Effects 0.000 claims description 24
- 238000010168 coupling process Methods 0.000 claims description 24
- 238000005859 coupling reaction Methods 0.000 claims description 24
- 239000007788 liquid Substances 0.000 claims description 18
- YGZSVWMBUCGDCV-UHFFFAOYSA-N chloro(methyl)silane Chemical compound C[SiH2]Cl YGZSVWMBUCGDCV-UHFFFAOYSA-N 0.000 claims description 15
- ZDHXKXAHOVTTAH-UHFFFAOYSA-N trichlorosilane Chemical compound Cl[SiH](Cl)Cl ZDHXKXAHOVTTAH-UHFFFAOYSA-N 0.000 claims description 5
- 239000005052 trichlorosilane Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 3
- 238000004821 distillation Methods 0.000 claims 11
- 239000005055 methyl trichlorosilane Substances 0.000 abstract description 15
- 239000000126 substance Substances 0.000 abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 6
- 239000012071 phase Substances 0.000 description 57
- 239000007789 gas Substances 0.000 description 48
- 239000000047 product Substances 0.000 description 38
- IJOOHPMOJXWVHK-UHFFFAOYSA-N trimethylsilyl-trifluoromethansulfonate Natural products C[Si](C)(C)Cl IJOOHPMOJXWVHK-UHFFFAOYSA-N 0.000 description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 9
- 238000007599 discharging Methods 0.000 description 8
- 238000005265 energy consumption Methods 0.000 description 8
- 229910052710 silicon Inorganic materials 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000009833 condensation Methods 0.000 description 6
- 230000005494 condensation Effects 0.000 description 6
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 6
- 238000003786 synthesis reaction Methods 0.000 description 6
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 4
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 4
- -1 methyl siloxane Chemical class 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 239000005049 silicon tetrachloride Substances 0.000 description 4
- 239000005051 trimethylchlorosilane Substances 0.000 description 4
- KTQYJQFGNYHXMB-UHFFFAOYSA-N dichloro(methyl)silicon Chemical compound C[Si](Cl)Cl KTQYJQFGNYHXMB-UHFFFAOYSA-N 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000007792 gaseous phase Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 239000005048 methyldichlorosilane Substances 0.000 description 2
- 229910000077 silane Inorganic materials 0.000 description 2
- 229920002379 silicone rubber Polymers 0.000 description 2
- 239000004945 silicone rubber Substances 0.000 description 2
- KZEVSDGEBAJOTK-UHFFFAOYSA-N 1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-2-[5-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]-1,3,4-oxadiazol-2-yl]ethanone Chemical compound N1N=NC=2CN(CCC=21)C(CC=1OC(=NN=1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)=O KZEVSDGEBAJOTK-UHFFFAOYSA-N 0.000 description 1
- JQMFQLVAJGZSQS-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-N-(2-oxo-3H-1,3-benzoxazol-6-yl)acetamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC(=O)NC1=CC2=C(NC(O2)=O)C=C1 JQMFQLVAJGZSQS-UHFFFAOYSA-N 0.000 description 1
- CONKBQPVFMXDOV-QHCPKHFHSA-N 6-[(5S)-5-[[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]methyl]-2-oxo-1,3-oxazolidin-3-yl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)C[C@H]1CN(C(O1)=O)C1=CC2=C(NC(O2)=O)C=C1 CONKBQPVFMXDOV-QHCPKHFHSA-N 0.000 description 1
- WTFUTSCZYYCBAY-SXBRIOAWSA-N 6-[(E)-C-[[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]methyl]-N-hydroxycarbonimidoyl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)C/C(=N/O)/C1=CC2=C(NC(O2)=O)C=C1 WTFUTSCZYYCBAY-SXBRIOAWSA-N 0.000 description 1
- DFGKGUXTPFWHIX-UHFFFAOYSA-N 6-[2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]acetyl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC(=O)C1=CC2=C(NC(O2)=O)C=C1 DFGKGUXTPFWHIX-UHFFFAOYSA-N 0.000 description 1
- 239000005046 Chlorosilane Substances 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- QABCGOSYZHCPGN-UHFFFAOYSA-N chloro(dimethyl)silicon Chemical compound C[Si](C)Cl QABCGOSYZHCPGN-UHFFFAOYSA-N 0.000 description 1
- KOPOQZFJUQMUML-UHFFFAOYSA-N chlorosilane Chemical compound Cl[SiH3] KOPOQZFJUQMUML-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011863 silicon-based powder Substances 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/20—Purification, separation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/08—Compounds containing halogen
- C01B33/107—Halogenated silanes
- C01B33/10778—Purification
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Abstract
The invention relates to a crude monomer separation energy-saving method, which comprises the steps of feeding a crude monomer into a first rectifying tower, feeding a high-boiling gas phase substance removed from the tower top into a reboiler at the tower bottom of a third rectifying tower, condensing, returning one part of the condensed high-boiling gas phase substance to the tower top of the first rectifying tower as tower reflux, and feeding the other part of the condensed high-boiling gas phase substance to a second rectifying tower. Extracting light components from the top of the second rectifying tower, and extracting light components from the bottom of the second rectifying tower to a third rectifying tower and a fourth rectifying tower; gas phase materials at the top of the rectifying tower III respectively enter a rectifying tower II and a rectifying tower IV kettle reboiler, one part of the condensed gas phase materials is returned to the rectifying tower as tower reflux, and the other part of the condensed gas phase materials is extracted; and a methyl trichlorosilane product is extracted from the top of the rectifying tower IV, and a dimethyl dichlorosilane product is extracted from the bottom of the rectifying tower IV. The gas phase material at the top of the rectifying tower I is used as a heat source of a reboiler of a rectifying tower III, the gas phase material at the top of the rectifying tower III is used as a heat source of a reboiler of a rectifying tower II and a reboiler of a rectifying tower IV respectively, the latent heat of the gas phase steam material at the top of the rectifying tower I and the rectifying tower III is utilized, the steam consumption is reduced by 50% in a same ratio, and the circulating water consumption is reduced by 50%.
Description
Technical Field
The invention relates to a crude monomer separation energy-saving method, belonging to the technical field of organic silicon production.
Background
The methyl chlorosilane mixed monomer comprises dimethyl dichlorosilane (dimethyl for short), methyl trichlorosilane (methyl for short), trimethyl monochlorosilane (trimethyl for short), methyl dichlorosilane (methyl for short contains hydrogen), high boiling point substances and low boiling point substances. As is well known, the synthesis of methyl chlorosilane monomers at home and abroad generally adopts a direct method synthesis process, silicon powder and chloromethane are used as raw materials, a methyl chlorosilane mixed monomer is directly synthesized under the action of a copper catalyst system, the methyl chlorosilane mixed monomer is rectified and separated to obtain a main target product dimethyl, and byproducts, namely methyl, methyl contain hydrogen, trimethyl, high-boiling residues and low-boiling residues. Dimethyl is hydrolyzed and cracked to produce various organosilicon intermediates, namely oligomeric methyl siloxane or alkoxy silane, and the oligomeric methyl siloxane or alkoxy silane is further processed into various organosilicon downstream products.
The purity requirement of dimethyl as a raw material is quite high when silicone oil and silicone rubber are prepared, and particularly, the purity of the dimethyl as a key raw material is required to reach more than 99.95 percent when high-temperature vulcanized silicone rubber is prepared. However, the crude monomer components are complex, the boiling point difference is small, and the dimethyl product rectified by the domestic organic silicon manufacturers at present has low purity and large energy consumption compared with the foreign advanced level, so that the market competitiveness of the product is low. The energy consumption for separating the methyl chlorosilane mixed monomer accounts for more than 80 percent of the whole organic silicon device, so that the related technical research on the separation and purification process of the methyl chlorosilane mixed monomer is necessary, and the energy consumption is reduced as much as possible under the condition of ensuring the product quality.
At present, the domestic technology mainly provides pressure-swing thermal coupling rectification of an upper-removing tower and a lower-removing tower, double-effect rectification thermal coupling of a binary tower in parallel connection, and pressure-swing thermal coupling rectification of the upper-removing tower and the binary tower, and the utilization rate of the thermal coupling is not high, and the energy consumption is still high.
Disclosure of Invention
The invention provides a monomer separation energy-saving method, which solves the problems of difficult extraction in the prior art and overcomes the problems of large steam and circulating water consumption and high energy consumption in monomer separation.
Technical terms used in the present invention describe:
coarse high-boiling residues: components with boiling point higher than 70.2 ℃ under normal pressure.
Low-boiling-point substances: a component having a boiling point of less than 60 ℃ at atmospheric pressure.
Crude monomer: the main components of the methyl chlorosilane mixed monomer are methyl trichlorosilane, dimethyl dichlorosilane, trimethyl monochlorosilane, methyl dichlorosilane, silicon tetrachloride and the like. The technical concept of the invention is as follows:
a crude monomer separation energy-saving method, enter the first rectifying column, the first rectifying column tower removes the high boiling gas phase supplies and all enters the third tower kettle reboiler of the rectifying column as the heat source, a part returns to the first rectifying column tower top as the tower reflux after the reboiler condensation, another part is as the second feeding of rectifying column, the tower kettle withdraws crude high boiling; chlorosilane components with low boiling points are extracted from the top of the second rectifying tower, and are extracted from the bottom of the second rectifying tower to be used as feeding materials of a third rectifying tower and a fourth rectifying tower; gas phase materials at the top of the third tower of the rectifying tower respectively enter a thermally coupled reboiler at the bottom of the second tower of the rectifying tower and a reboiler at the bottom of the fourth tower of the rectifying tower to be used as heat sources, a part of the condensed gas phase materials is used as tower reflux and returned to the top of the third tower of the rectifying tower, the other part of the condensed gas phase materials is used as a methyl trichlorosilane product to be extracted, and a dimethyl dichlorosilane product is extracted from the tower bottom; and a methyl trichlorosilane product is extracted from the top of the rectifying tower IV, and a dimethyl dichlorosilane product is extracted from the bottom of the rectifying tower IV.
The process adopting the crude monomer separation energy-saving device comprises the following steps:
(1) feeding an organic silicon crude monomer into a first rectifying tower 1, removing high-boiling gas phase materials at the top of the first rectifying tower 1, feeding the materials into a third tower kettle reboiler 8 of the rectifying tower as a heat source, condensing the materials by the third tower kettle reboiler 8 of the rectifying tower, and feeding the materials into a second rectifying tower 2 by a reflux pump 13 of the rectifying tower;
(2) the gas phase at the top of the second rectifying tower 2 is condensed by a second rectifying tower condenser 7 and enters a second rectifying tower reflux groove 12, a part of the material in the second rectifying tower reflux groove 12 is conveyed by a second rectifying tower reflux pump 15 and returns to the top of the second rectifying tower 2 as tower reflux, the other part of the extracted component 21 with the boiling point lower than 60 ℃ enters a subsequent rectifying tower for separation, and the extracted component at the bottom of the tower is conveyed by a second rectifying tower kettle liquid pump 16 and serves as the feed of a third rectifying tower 3 and a fourth rectifying tower 4;
(3) gas phase materials at the top of the third rectifying tower 3 respectively enter a second rectifying tower kettle reboiler 6 and a fourth rectifying tower kettle reboiler 9 as heat sources, after condensation, the gas phase materials are respectively led to a second rectifying tower coupling reflux pump 14 and a fourth rectifying tower coupling reflux pump 17 of the rectifying tower to be used as tower reflux and return to the top of the third rectifying tower 3, the other part of the gas phase materials is taken as a methyl trichlorosilane product 23 to be extracted, and a dimethyl dichlorosilane product 22 is extracted at the bottom of the rectifying tower;
(4) the gas phase at the top of the rectifying tower four 4 is condensed by a rectifying tower four condenser 10 and enters a rectifying tower four reflux groove 11, a part of the material in the rectifying tower four reflux groove 11 is conveyed by a rectifying tower four reflux pump 18 and returns to the top of the rectifying tower four 4 as tower reflux, the other part of the material is used for extracting a trichlorosilane product 25, and the tower kettle is used for extracting a dimethyldichlorosilane product 24.
In the step (1), the organosilicon crude monomer is a mixture composed of methyl chlorosilane, and comprises 82-87% of dimethyl dichlorosilane, 5-9% of monomethyl chlorosilane, 2-5% of high boiling point substances and 4-7% of light components in percentage by mass.
In the step (1), the high-boiling gas phase materials removed from the top of the rectifying tower I1 completely enter a rectifying tower three-tower kettle reboiler 8 to be used as a heat source.
After being condensed by a reboiler 8 at the third tower kettle of the rectifying tower in the step (1), 40-90% of the condensed liquid is returned to the top of the first rectifying tower 1 as tower reflux through a reflux pump 13 of the rectifying tower, and the other part of the condensed liquid is used as the feeding material of the second rectifying tower 2.
As a preferred scheme, the material extracted from the second 2 tower bottom of the rectification tower is conveyed by 50%, 55%, 60%, 65%, 70%, 75% and 80% volume fraction through the second 2 tower bottom liquid pump 16 to the third 3 rectification tower, and the corresponding rest material is conveyed to the fourth 4 rectification tower.
In the step (1), the top temperature of the first rectifying tower 1 is controlled at 110-150 ℃, and the top pressure is controlled at 0.30-0.6MPa, and as a preferable scheme, the top temperature of the first rectifying tower 1 is controlled at 120-145 ℃, and the top pressure is controlled at 0.35-0.5 MPa.
And (3) conveying 70-99% of the material in the second rectifying tower reflux tank 12 in the step (2) through a second rectifying tower reflux pump 15 to return to the top of the second rectifying tower 2, and introducing the other part of the extracted component 21 with the boiling point lower than 60 ℃ into a subsequent rectifying tower for separation.
In the step (2), the liquid from the second 2 tower bottom of the rectifying tower is conveyed by a liquid pump 16 of the rectifying tower to 50-80% of the liquid to a third 3 rectifying tower, and the rest is conveyed to a fourth 4 rectifying tower.
Preferably, the material extracted from the second 2 tower bottom of the rectifying tower is conveyed by 50%, 55%, 60%, 65%, 70%, 75% and 80% volume fraction through the second 2 tower bottom liquid pump 16 to the third rectifying tower 3, and the corresponding rest material is conveyed to the fourth rectifying tower 4.
In the step (2), the temperature of the second tower 2 of the rectifying tower is controlled to be 80-100 ℃, the tower pressure is controlled to be 0.05-0.2MPa, and as a preferred scheme, the temperature of the second tower 2 of the rectifying tower is controlled to be 85-95 ℃.
In the step (3), the gas phase material at the top of the third rectifying tower 3 is conveyed to a reboiler 6 at the second rectifying tower kettle by 40-60 percent, and the rest is conveyed to a reboiler 9 at the fourth rectifying tower kettle.
Preferably, the gas phase material at the top of the third 3 tower of the rectifying tower is delivered to the reboiler 6 at the second tower of the rectifying tower in volume fractions of 40%, 45%, 50%, 55% and 60%, and the corresponding residual material is delivered to the reboiler 9 at the fourth 4 tower of the rectifying tower.
And (4) in the step (3), the condensate of the reboiler 6 at the second tower bottom of the rectifying tower and the condensate of the reboiler 9 at the fourth tower bottom of the rectifying tower partially returns to the top of the third 3 rectifying tower through the reflux pump 14 at the second coupling of the rectifying tower and the reflux pump 17 at the fourth coupling of the rectifying tower, and part of the condensate is taken as a methyltrichlorosilane product 23, wherein the reflux ratio is 100-180.
In the step (3), the top temperature of the third rectifying tower 3 is controlled at 90-120 ℃, and the top pressure is controlled at 0.10-0.3 MPa.
And (5) in the step (4), part of the materials in the rectifying tower four-reflux groove 11 is conveyed to the top of the rectifying tower through a rectifying tower four-reflux pump 18, and the other part is used for extracting a trichlorosilane product 25 with a reflux ratio of 100-180.
In the step (4), the temperature of the fourth 4 tower kettle of the rectifying tower is controlled to be 80-100 ℃, the pressure of the tower kettle is controlled to be 0.05-0.15MPa, and as a preferred scheme, the temperature of the fourth 4 tower kettle of the rectifying tower is controlled to be 85-98 ℃.
The gas phase temperature at the top of the rectifying tower I1 is 10-40 ℃ higher than the temperature of the bottom of the rectifying tower III.
The gas phase temperature at the top of the third rectifying tower 3 is 10-40 ℃ higher than the temperature of the bottom of the second rectifying tower and the fourth rectifying tower.
The technical advantages are as follows:
the invention has simple process technology, strict control condition and good application prospect and application value, and compared with the prior art: in the conventional process, the reboilers of the rectifying tower I, the rectifying tower II and the rectifying tower III are heated by adopting steam, and the tower top is condensed by adopting circulating water. The invention makes full use of the material components and characteristics, divides the rectifying tower III in the conventional process into the rectifying tower III and the rectifying tower IV, and simultaneously, pressurizes the rectifying tower I and the rectifying tower III to operate, thereby improving the temperature of the top of the rectifying tower I and the top of the rectifying tower III. The invention divides the material in the bottom of the rectifying tower into two parts according to a certain proportion to be rectified and separated, namely, the three parts are rectified by the three rectifying towers and the four parts are respectively rectified, so that the heat coupling of the three rectifying towers 3, the four rectifying towers 4 and the two rectifying towers 2 in the scheme is realized, the purpose of energy saving is achieved, more towers do not need to be disassembled, and the investment is saved. The split is calculated calorimetrically. The pressurization is to obtain the temperature difference, and the purpose that the gas phase at the top of the rectifying tower III 3 enters the rectifying tower IV 4 and the rectifying tower II 2 is achieved. Too high a pressure may result in reduced separation efficiency and heat mismatch in rectifier column three 3);
firstly, all high-temperature gas-phase materials on the top of the first rectifying tower are used as heat sources of a reboiler of a third rectifying tower kettle, and then the gas-phase materials on the top of the third rectifying tower are respectively used as heat sources of a reboiler of a second rectifying tower kettle and a reboiler of a fourth rectifying tower kettle.
Drawings
FIG. 1 is a structural diagram of a crude monomer separation energy-saving system of the invention, wherein 1 is a first rectifying tower; 2, a second rectifying tower; 3, a third rectifying tower; 4, a rectifying tower IV; 5, a reboiler of the rectifying tower; 6, a reboiler at a second tower kettle of the rectifying tower; 7, a second condenser of the rectifying tower; 8, a rectifying tower three-tower kettle reboiler; 9 rectifying tower four-tower kettle reboiler; 10, a rectifying tower four condenser; 11 a rectifying tower four reflux groove; 12 a second reflux groove of the rectifying tower; 13, a reflux pump of the rectifying tower; 14, coupling a reflux pump with the second rectifying tower; 15 a second reflux pump of the rectifying tower; 16 a second-kettle liquid pump of the rectifying tower; 17 the rectifying tower is coupled with a reflux pump; 18 a rectifying tower four reflux pump; 19 a crude monomer feed pipe; 20 a coarse high-boiling-point substance discharge pipe; 21 discharging a pipe I; 22, discharging a pipe II; 23 discharging a pipe III; a fourth discharge pipe 24; and 25, discharging a pipe V.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and examples, which are merely preferred embodiments of the invention, and are not intended to be exhaustive. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative efforts belong to the protection scope of the present invention.
Example 1
A crude monomer separation energy-saving device, a crude monomer feed pipe 19 is connected with a rectifying tower I1, the top of the rectifying tower I1 is connected with a rectifying tower three-tower kettle reboiler 8 arranged at the bottom of a rectifying tower III 3 through a gas phase pipeline;
a reboiler 8 at the third tower bottom of the rectifying tower is connected with a second rectifying tower 2 through a reflux pump 13 of the rectifying tower;
the bottom of the second rectifying tower 2 is respectively connected with a third rectifying tower 3 and a fourth rectifying tower 4 through a second rectifying tower kettle liquid pump 16. The bottom of the rectifying tower I1 is provided with a reboiler 5 of the rectifying tower, and the bottom of the rectifying tower I1 is connected to a coarse high-boiling-point substance discharging pipe 20. A reboiler 8 of the rectifying tower, a third tower kettle and a third tower kettle is connected with the upper part of the rectifying tower I1 through a reflux pump 13 of the rectifying tower. And a reboiler 6 at the top of the third rectifying tower 3 and the bottom of the second rectifying tower 2.
The top of the second rectifying tower 2 is connected with a second rectifying tower condenser 7, the second rectifying tower condenser 7 is connected with a second rectifying tower reflux groove 12, the second rectifying tower reflux groove 12 is connected with a second rectifying tower reflux pump 15, one path of the second rectifying tower reflux pump 15 is connected to the upper portion of the second rectifying tower 2, and the other path of the second rectifying tower reflux pump 15 is connected to a first discharging pipe 21.
The top of the rectifying tower III 3 is connected with a rectifying tower four-tower kettle reboiler 9 arranged at the bottom of the rectifying tower IV 4. The top of the rectifying tower four 4 is connected with a rectifying tower four condenser 10, the rectifying tower four condenser 10 is connected with a rectifying tower four reflux groove 11, the rectifying tower four reflux groove 11 is connected with a rectifying tower four reflux pump 18, the rectifying tower four reflux pump 18 is connected with a discharge pipe five 25 all the way, and is connected with the rectifying tower four 4 all the way. The bottom of the rectifying tower four 4 is connected to a discharge pipe four 24.
And a second rectifying tower kettle reboiler 6 and a fourth rectifying tower kettle reboiler 9 are respectively connected with a second rectifying tower coupling reflux pump 14 and a fourth rectifying tower coupling reflux pump 17. The second rectifying tower coupling reflux pump 14 and the fourth rectifying tower coupling reflux pump 17 are respectively connected to a third discharging pipe 23 after being converged through a pipeline, one path is connected to a third rectifying tower 3, and the bottom of the third rectifying tower 3 is connected to a second discharging pipe 22.
The material stream qualification parameter ranges are as follows:
and (3) extracting a stream 20 from the bottom of the rectifying tower:
dimethyl dichlorosilane: 20-50%, trimethylchlorosilane: 0.01-0.1%, high-boiling substance: 50 to 80 percent.
And stream 21 is extracted from the top of the second rectifying tower:
mono-methyltrichlorosilane: 0.1-8%, trimethylchlorosilane: 40-60%, monomethyldichlorosilane: 30-50%, dimethylchlorosilane 5-10%, silicon tetrachloride: 0-0.55%, low boiling substance: 3 to 10 percent.
And (3) producing a stream 22 at the bottom of the three towers of the rectifying tower:
dimethyl dichlorosilane: 99-100%, monomethyltrichlorosilane: 0.005-0.02%, high boiling substance: 0.04-0.2 percent.
And a stream 23 is extracted from the top of the rectifying tower at the third tower:
monomethyltrichlorosilane: 98-100%, dimethyldichlorosilane: 0.05-1%, trimethylchlorosilane: 0.01-0.5%, silicon tetrachloride: 0.01 to 0.3 percent.
And a stream 24 is extracted from the bottom of the four towers of the rectifying tower:
dimethyl dichlorosilane: 99-100%, monomethyltrichlorosilane: 0.005-0.02%, high boiling substance: 0.04 to 0.2 percent.
A stream 25 extracted from the top of the four columns of the rectifying tower:
mono-methyltrichlorosilane: 98-100%, dimethyldichlorosilane: 0.05-1%, trimethylchlorosilane: 0.01-0.5%, silicon tetrachloride: 0.01 to 0.3 percent.
Example 2
Crude monomers from the synthesis apparatus (pressure 0.6MPa, temperature 40 ℃, 85% dimethyldichlorosilane, 8% monomethylchlorosilane, 2% high boilers, 5% lights) were used.
The energy-saving process for rectifying the crude monomer by using the embodiment 1 is as follows:
(1) the method comprises the following steps of (1) enabling organic silicon crude monomers to enter a rectifying tower I1 at a speed of 15t/h, enabling all high-boiling gas-phase materials removed from the top of the rectifying tower I1 to enter a rectifying tower three-tower kettle reboiler 8 as a heat source, condensing the materials by the rectifying tower three-tower kettle reboiler 8, pumping 50% of materials with volume fraction to flow back to the rectifying tower I1 through a rectifying tower reflux pump 13, enabling the rest 50% of materials to be fed into a rectifying tower II 2, enabling the top temperature of the rectifying tower I1 to be 130 ℃ and the pressure to be 0.4 MPa;
(2) the gas phase at the top of the second rectifying tower 2 is condensed by a second rectifying tower condenser 7 and enters a second rectifying tower reflux groove 12, the material in the second rectifying tower reflux groove 12 is conveyed by a second rectifying tower reflux pump 15 to be 90% in volume fraction as tower reflux and returns to the top of the second rectifying tower 2, 10% of the extracted component 21 with the boiling point lower than 60 ℃ enters a subsequent rectifying tower for separation, 60% of the material in volume fraction is conveyed by a second rectifying tower kettle liquid pump 16 from the second rectifying tower kettle 2 to be used as the feed of a third rectifying tower 3, and the remaining 40% of the material is used as the feed of a fourth rectifying tower 4; the temperature of the second 2 tower bottom of the rectifying tower is 80 ℃, and the pressure of the tower bottom is 0.05 MPa;
(3) a third rectifying tower 3 is heated by a third rectifying tower kettle reboiler 8, 60% volume fraction material of gas phase material at the top of the third rectifying tower 3 enters a second rectifying tower kettle reboiler 6, 40% volume fraction material enters a fourth rectifying tower kettle reboiler 9 to serve as a heat source, after condensation, part of the gas phase material is returned to the top of the third rectifying tower 3 as tower reflux through a second rectifying tower coupling reflux pump 14 and a fourth rectifying tower coupling reflux pump 17 respectively, reflux is realized, the reflux ratio is 120, the other part of the gas phase material is extracted as a methyltrichlorosilane product 23, and a dimethyldichlorosilane product 22 is extracted at the bottom of the tower; the temperature of the third 3 tower kettle of the rectifying tower is 110 ℃, the temperature of the top of the tower is 100 ℃, and the pressure of the tower kettle is 0.15 MPa;
(4) condensing the gas phase at the top of the rectifying tower four 4 into a rectifying tower four reflux groove 11 through a rectifying tower four condenser 10, conveying a part of the material in the rectifying tower four reflux groove 11 through a rectifying tower four reflux pump 18 as tower reflux to return to the top of the rectifying tower four 4 to realize reflux, wherein the reflux ratio is 100, a trichlorosilane product 25 is extracted from the other part, and a dimethyldichlorosilane product 24 is extracted from the tower bottom; the temperature of the fourth 4 tower bottom of the rectifying tower is 85 ℃, and the pressure of the tower bottom is 0.15 MPa.
To this process condition of this application, the volume of this application to the trend selection and trend of each gaseous phase material has carried out the condition of refining to condenser and reboiler load influence, and the volume of walking of discovery gaseous phase is huge to the influence that realizes the energy-conserving effect of rectification process, specifically as follows:
note: the percentages are volume fractions.
The step (1) corresponds to the material which is refluxed to the first rectifying tower 1 by the reflux pump 13 of the rectifying tower and serves as the split flow condition of the feeding of the second rectifying tower 2.
The step (2) corresponds to the situation that the material which is extracted from the second rectifying tower 2 and is conveyed to the third rectifying tower 3 through the second rectifying tower kettle liquid pump 16 and is used as the split flow of the feeding material of the fourth rectifying tower 4.
The step (3) corresponds to the flow splitting condition that the gas phase material at the top of the rectifying tower III 3 enters a rectifying tower second tower kettle reboiler 6 and enters a rectifying tower fourth tower kettle reboiler 9 as a heat source.
Depending on the process steps and parameters of implementation 2, the ratio of the feed streams to rectification column 3 and to rectification column 4 of rectification column 2 is varied, for example, the amount of depreciation column 3 is lower than depreciation column 4, and the amount of cooling required for rectification column 4 is increased, as in examples 2 to 15, 2 to 16.
According to the process steps and parameters of the embodiment 2, the distribution of the gas phase in the rectifying tower three 3 to the rectifying tower four 4 and the gas phase in the rectifying tower 2 is greatly changed, for example, the distribution in the rectifying tower four 4 exceeds 70%, the distribution in the other rectifying tower 2 is changed, the rectifying tower two 2 can normally operate only by additionally supplementing heat, and the rectifying tower four 4 is subjected to overpressure.
Example 3
According to the process steps of the embodiment 2, the pressure of the rectifying tower 1 is 0.25Mpa, the temperature is 119 ℃, in order to realize that the gas phase at the top of the rectifying tower is used as a heating medium of a reboiler 8 of the rectifying tower 3, the temperature of the rectifying tower 3 is controlled to be 100 ℃, and the temperature at the top of the rectifying tower is about 90 ℃. The gas phase material of the rectifying tower can not be used as a heating medium, and the rectifying tower 2 and the rectifying tower 4 need steam for heating.
Example 4
According to the process steps of the embodiment 2, the pressure of the rectifying tower III 3 is controlled to be 0.25MPa, and the separation efficiency is poor. The content of the monomethyl trichlorosilane in the tower bottom product exceeds 0.02 percent.
Example 5
Crude monomers from the synthesis apparatus (pressure 0.67MPa, temperature 45 ℃, 85.5% dimethyldichlorosilane, 7.8% monomethylchlorosilane, 2.4% high boilers, 4.3% lights).
The energy-saving process for rectifying the crude monomer by using the embodiment 1 is as follows:
(1) the method comprises the following steps of (1) enabling an organic silicon crude monomer to enter a rectifying tower I1 at a flow rate of 25.5t/h, enabling all high-boiling gas-phase materials removed from the top of the rectifying tower I1 to enter a rectifying tower three-tower kettle reboiler 8 as a heat source, condensing the high-boiling gas-phase materials by the rectifying tower three-tower kettle reboiler 8, pumping 78% of materials with volume fraction to the top of the rectifying tower I1 through a rectifying tower reflux pump 13, enabling the rest 22% of the materials to be fed into a rectifying tower II 2, and extracting crude high-boiling materials 20 from a tower kettle; the temperature of the top of the rectifying tower 1 is controlled at 135 ℃, and the pressure of the top of the rectifying tower is controlled at 0.45 MPa.
(2) The gas phase at the top of the second rectifying tower 2 is condensed by a second rectifying tower condenser 7 and enters a second rectifying tower reflux groove 12, the material in the second rectifying tower reflux groove 12 is conveyed by a second rectifying tower reflux pump 15 to 97.5% of material with volume fraction as tower reflux and returns to the top of the second rectifying tower 2, 2.5% of extracted low-boiling-point component 21 of the mono-methyl trichlorosilane enters a subsequent rectifying tower for separation, 74% of material with volume fraction is conveyed by a second rectifying tower kettle liquid pump 16 from the tower kettle to be used as the feed of a third rectifying tower 3, and the rest 26% of material is used as the feed of a fourth rectifying tower 4; the temperature of the second 2 tower bottom of the rectification tower is controlled at 87 ℃, and the pressure of the tower bottom is controlled at 0.06 MPa.
(3) A third rectifying tower 3 is heated by a third rectifying tower kettle reboiler 8, 52% volume fraction material of gas phase material at the top of the third rectifying tower 3 enters a second rectifying tower kettle reboiler 6 and 48% volume fraction material of a fourth rectifying tower kettle reboiler 9 as heat sources, after condensation, part of the condensed gas phase material is returned to the top of the third rectifying tower 3 as tower reflux by a second rectifying tower coupling reflux pump 14 and a fourth rectifying tower coupling reflux pump 17, reflux ratio is 140, the other part of the condensed gas phase material is extracted as a methyltrichlorosilane product 23, and a dimethyldichlorosilane product 22 is extracted at the bottom of the tower; the top temperature of the third rectifying tower 3 is controlled at 107 ℃, and the top pressure is controlled at 0.2 MPa.
(4) Condensing gas phase at the top of the fourth 4 tower top of the rectifying tower into a fourth rectifying tower reflux groove 11 through a fourth rectifying tower condenser 10, conveying a part of material in the fourth rectifying tower reflux groove 11 through a fourth rectifying tower reflux pump 18 as tower reflux to return to the top of the fourth 4 tower of the rectifying tower to realize reflux, wherein the reflux ratio is 160, a methyltrichlorosilane product 25 is extracted from the other part, and a dimethyldichlorosilane product 24 is extracted from the tower kettle; the temperature of the four 4 tower kettles of the rectifying tower is controlled at 90 ℃, and the pressure of the tower kettles is controlled at 0.07 MPa.
The process is controlled to be the same as the energy-saving process for separating the crude monomer in the example 5, only the temperature of the second tower kettle of the rectifying tower is controlled to be 70 ℃, the pressure is controlled to be 0.05MPa, and the process is carried out in the example 5-1.
Similarly, the process was controlled to be the same as the energy-saving process for crude monomer rectification in example 5, only the temperature of the second column bottom of the rectification column was controlled to be 75 ℃, the pressure was controlled to be 0.1MPa, and the process performed was example 5-2.
Similarly, the process is controlled to be the same as the energy-saving process for rectifying the crude monomer in example 5, only the temperature of the second tower bottom of the rectifying tower is controlled to be 90 ℃, the pressure is controlled to be 0.12MPa, and the process is carried out in example 5-3.
Similarly, the process was controlled to the same energy saving process for crude monomer rectification as in example 5, except that the temperature in the second column bottom of the rectification column was controlled to 100 ℃ and the pressure was controlled to 0.20MPa, and the process was carried out as in example 5-4.
Similarly, the process was controlled to the same energy saving process for crude monomer rectification as in example 5, except that the temperature in the second column bottom of the rectification column was controlled to 110 ℃ and the pressure was controlled to 0.29MPa, and the process was carried out as in example 5-5.
Under the condition of the same treatment capacity and product quality, the energy consumption comparison data of the process and the system are as follows:
as can be seen from the comparison of the data, by adopting the process and the system, under the condition of the same treatment capacity and product quality, the heat consumption is only 47.25 percent of that of the conventional process, the load of the condenser is 39.16 percent of that of the conventional process, and the consumption of energy and circulating water is greatly reduced.
Example 6
Crude monomers from the synthesis apparatus (pressure 0.55MPa, temperature 41 ℃, containing 83.7% dimethyldichlorosilane, 7.5% monomethylchlorosilane, 2.8% high boilers, 6.0% lights).
The energy-saving process for rectifying the crude monomer by using the embodiment 1 is as follows:
(1) the method comprises the following steps of (1) enabling an organic silicon crude monomer to enter a rectifying tower I1 at a flow rate of 20.5t/h, enabling all high-boiling gas-phase materials removed from the top of the rectifying tower I1 to enter a rectifying tower III kettle reboiler 8 as a heat source, condensing the high-boiling gas-phase materials by the rectifying tower III kettle reboiler 8, pumping 68% of materials with volume fraction to flow back to the rectifying tower I1 through a rectifying tower reflux pump 13, enabling the rest 32% of the materials to be fed into a rectifying tower II 2, and extracting crude high-boiling materials 20 from a tower kettle; the top temperature of the rectifying tower 1 is controlled at 132 ℃, and the top pressure is controlled at 0.42 MPa.
(2) The gas phase at the top of the second rectifying tower 2 is condensed by a second rectifying tower condenser 7 and enters a second rectifying tower reflux groove 12, the material in the second rectifying tower reflux groove 12 is conveyed by a second rectifying tower reflux pump 15 to 88% by volume of the material as tower reflux and returns to the top of the second rectifying tower 2, 12% of the component 21 with low boiling point of the methyl trichlorosilane is extracted and enters a subsequent rectifying tower for separation, 72% by volume of the material is extracted from the tower kettle and conveyed by a second rectifying tower kettle liquid pump 16 to form a third rectifying tower 3, and the rest 28% of the material is fed as a fourth rectifying tower 4; the temperature of the second 2 tower bottom of the rectifying tower is controlled at 90 ℃, and the pressure of the tower bottom is controlled at 0.08 MPa.
(3) A third rectifying tower 3 is heated by a third rectifying tower kettle reboiler 8, 53 volume percent of gas phase materials at the top of the third rectifying tower 3 enter a second rectifying tower kettle reboiler 6, 47 volume percent of gas phase materials at the top of the third rectifying tower enter a fourth rectifying tower kettle reboiler 9 to serve as a heat source, after condensation, the condensed gas phase materials respectively pass through a second rectifying tower coupling reflux pump 14 and a fourth rectifying tower coupling reflux pump 17, and are partially returned to the top of the third rectifying tower 3 as tower reflux, so that reflux is realized, the reflux ratio is 155, the other part of the condensed gas phase materials is extracted as a methyltrichlorosilane product 23, and a dimethyldichlorosilane product 22 is extracted at the bottom of the tower; the top temperature of the third rectifying tower 3 is controlled at 109 ℃, and the top pressure is controlled at 0.21 MPa.
(4) Condensing gas phase at the top of the fourth 4 tower top of the rectifying tower into a fourth rectifying tower reflux groove 11 through a fourth rectifying tower condenser 10, conveying a part of material in the fourth rectifying tower reflux groove 11 through a fourth rectifying tower reflux pump 18 as tower reflux to return to the top of the fourth 4 tower of the rectifying tower to realize reflux, wherein the reflux ratio is 165, extracting a methyltrichlorosilane product 25 from the other part, and extracting a dimethyldichlorosilane product 24 from the tower kettle; the temperature of the four 4 tower bottom of the rectifying tower is controlled at 92 ℃, and the pressure of the tower bottom is controlled at 0.08 MPa.
The process is controlled to be the same as the energy-saving process for separating the crude monomer in the embodiment 6, the temperature of the top of the rectifying tower is controlled to be 85 ℃, the pressure is controlled to be 0.05MPa, and the process is carried out in the embodiment 6-1.
Similarly, the process was controlled to be the same as the energy-saving process for crude monomer rectification in example 5, except that the temperature at the top of the rectifying column was controlled to 90 ℃ and the pressure was controlled to 0.06MPa, and the process performed was example 6-2.
Similarly, the process was controlled to be the same as the energy-saving process for crude monomer rectification in example 5, except that the temperature at the top of the rectifying column was controlled to 95 ℃ and the pressure was controlled to 0.11MPa, and the process was carried out in example 6-3.
Similarly, the process was controlled to the same energy saving process for crude monomer rectification as in example 5, except that the temperature at the top of the rectifying column was controlled to 115 ℃ and the pressure was controlled to 0.26MPa, and the process was carried out as in example 6-4.
Similarly, the process is controlled to be the same as the energy-saving process for rectifying the crude monomer in example 5, the temperature at the top of the rectifying tower is controlled to be 120 ℃, the pressure is controlled to be 0.29MPa, and the process is carried out in example 6-5.
Similarly, the process was controlled to be the same as the energy-saving process for crude monomer rectification in example 5, except that the temperature at the top of the rectifying column was controlled to 125 ℃ and the pressure was controlled to 0.37MPa, and the processes performed were examples 6 to 6.
Under the condition of the same treatment capacity and product quality, the energy consumption comparison data of the process and the system are as follows:
it can be seen from the comparison of the data that the process and the system have the advantages that under the condition of the same treatment capacity and product quality, the heat consumption is only 49.06 percent of that of the conventional process, the load of a condenser is 42.00 percent of that of the conventional process, and the consumption of energy and circulating water is greatly reduced.
Example 7
Crude monomers from the synthesis apparatus (pressure 0.56MPa, temperature 42 ℃, 85.8% dimethyldichlorosilane, 6.8% monomethylchlorosilane, 3.5% high boilers, 3.9% lights).
The energy-saving process for rectifying the crude monomer by using the embodiment 1 is as follows:
(1) the method comprises the following steps of (1) enabling an organic silicon crude monomer to enter a rectifying tower I1 at a flow rate of 20.5t/h, enabling all high-boiling gas-phase materials removed from the top of the rectifying tower I1 to enter a rectifying tower three-tower kettle reboiler 8 as a heat source, condensing the high-boiling gas-phase materials by the rectifying tower three-tower kettle reboiler 8, pumping 77% of materials with volume fraction to flow back to the rectifying tower I1 through a rectifying tower reflux pump 13, enabling the rest 23% of materials to be fed into a rectifying tower II 2, and extracting crude high-boiling 20 from a tower kettle; the temperature of the top of the rectifying tower 1 is controlled at 138 ℃, and the pressure of the top of the rectifying tower is controlled at 0.48 MPa.
(2) The gas phase at the top of the second rectifying tower 2 is condensed by a second rectifying tower condenser 7 and enters a second rectifying tower reflux groove 12, the material in the second rectifying tower reflux groove 12 is conveyed by a second rectifying tower reflux pump 15 to be 93% in volume fraction and returns to the top of the second rectifying tower 2 as tower reflux, 7% of the extracted low-boiling-point component 21 of the mono-methyl trichlorosilane enters a subsequent rectifying tower for separation, 68% in volume fraction is conveyed by a second rectifying tower kettle liquid pump 16 from the tower kettle to be a third rectifying tower 3, and the rest 32% is fed as a fourth rectifying tower 4; the temperature of the second 2 tower bottom of the rectifying tower is controlled at 93 ℃, and the pressure of the tower bottom is controlled at 0.09 MPa.
(3) A third rectifying tower 3 is heated by a third rectifying tower kettle reboiler 8, 55% volume fraction material of gas phase material at the top of the third rectifying tower 3 enters a second rectifying tower kettle reboiler 6, and 45% volume fraction material enters a fourth rectifying tower kettle reboiler 9 as a heat source, after condensation, part of the condensed gas phase material is returned to the top of the third rectifying tower 3 as tower reflux by a second rectifying tower coupling reflux pump 14 and a fourth rectifying tower coupling reflux pump 17, so that reflux is realized, the reflux ratio is 138, the other part of the condensed gas phase material is extracted as a methyltrichlorosilane product 23, and a dimethyldichlorosilane product 22 is extracted at the bottom of the tower; the top temperature of the third rectifying tower 3 is controlled at 112 ℃, and the top pressure is controlled at 0.23 MPa.
(4) Condensing gas phase at the top of the fourth 4 tower top of the rectifying tower into a fourth rectifying tower reflux groove 11 through a fourth rectifying tower condenser 10, conveying a part of material in the fourth rectifying tower reflux groove 11 through a fourth rectifying tower reflux pump 18 as tower reflux to return to the top of the fourth 4 tower of the rectifying tower to realize reflux, wherein the reflux ratio is 170, a methyltrichlorosilane product 25 is extracted from the other part, and a dimethyldichlorosilane product 24 is extracted from the tower kettle; the temperature of the four 4 tower bottom of the rectifying tower is controlled at 94 ℃, and the pressure of the tower bottom is controlled at 0.09 MPa.
Under the condition of the same treatment capacity and product quality, the energy consumption comparison data of the process and the system are as follows:
it can be seen from the comparison of the data that the process and the system have the advantages that under the condition of the same treatment capacity and product quality, the heat consumption is only 48.40 percent of that of the conventional process, the load of a condenser is 40.93 percent of that of the conventional process, and the consumption of energy and circulating water is greatly reduced.
The steps and the process conditions are the same as those of the example 7, the pressure at the top of the first rectifying tower 1 is controlled to be 0.30MPa, and the temperature at the top of the first rectifying tower 1 is correspondingly reduced to 110 ℃; controlling the pressure of the three towers of the rectifying tower to be 0.13MPa, and correspondingly increasing the temperature of the kettle of the three towers of the rectifying tower to 105 ℃; under the condition, the temperature difference between the tower bottom of the first rectifying tower and the tower bottom of the third rectifying tower is 5 ℃, and the condition does not satisfy that the gas phase temperature at the top of the first rectifying tower 1 is 10-40 ℃ higher than the tower bottom temperature of the third rectifying tower, so that a reboiler 8 of the third rectifying tower cannot effectively provide heat for the third rectifying tower, and a system cannot normally operate.
The steps and the process conditions are the same as those of the example 7, the pressure at the top of the first rectifying tower 1 is controlled to be 0.49MPa, and the temperature at the top of the first rectifying tower 1 correspondingly rises to 140 ℃; controlling the pressure of the three towers of the rectifying tower to be 0.1MPa, and correspondingly reducing the temperature of the three towers of the rectifying tower to 90 ℃; under the condition, the temperature difference between the tower bottom of the first rectifying tower and the tower bottom of the third rectifying tower is 50 ℃, and the condition does not meet the condition that the gas phase temperature at the top of the first rectifying tower 1 is 10-40 ℃ higher than the tower bottom temperature of the third rectifying tower, so that the reboiler 8 of the third rectifying tower provides too much heat for the third rectifying tower, and the system cannot normally operate.
The steps and the process conditions are the same as those of the example 7, the pressure at the top of the first rectifying tower 1 is controlled to be 0.35MPa, and the temperature at the top of the first rectifying tower 1 is correspondingly reduced to 120 ℃; controlling the pressure of the three towers of the rectifying tower to be 0.30MPa, and correspondingly increasing the temperature of the kettle of the three towers of the rectifying tower to 120 ℃; the temperature difference between the first rectifying tower and the third rectifying tower is 0 ℃ under the condition, the temperatures of the first rectifying tower and the third rectifying tower are the same, and the conditions do not satisfy that the gas phase temperature at the top of the first rectifying tower 1 is 10-40 ℃ higher than the temperature of the third rectifying tower, so that a reboiler 8 of the third rectifying tower cannot provide heat for the third rectifying tower, and a system cannot normally operate.
The steps and the process conditions are the same as those of the example 7, the pressure of the third rectifying tower is controlled to be 0.10MPa, the temperature of the kettle of the third rectifying tower is correspondingly reduced to 90 ℃, the pressure of the top of the second rectifying tower is controlled to be 0.0.08MPa, the temperature of the top of the second rectifying tower 2 is correspondingly reduced to 90 ℃, and the reboiler 6 of the second rectifying tower cannot provide heat for the second rectifying tower and the system cannot normally operate because the temperature difference between the third rectifying tower and the second rectifying tower is not in the range of 10-40 ℃ under the same temperature.
The steps and the process conditions are the same as those of the example 7, the pressure of the third rectifying tower is controlled to be 0.38MPa, the temperature of the kettle of the third rectifying tower correspondingly rises to 130 ℃, the pressure of the top of the second rectifying tower is controlled to be 0.05MPa, the temperature of the top of the second rectifying tower 2 correspondingly decreases to 80 ℃, the temperature difference of the kettle of the third rectifying tower and the kettle of the second rectifying tower is 50 ℃ due to the condition that the temperature of the gas phase at the top of the third rectifying tower 3 is 10-40 ℃ higher than that of the kettle of the second rectifying tower, and the reboiler 6 of the second rectifying tower supplies too much heat to the second rectifying tower, so that the system can not normally operate.
The steps and the process conditions are the same as those of the example 7, the pressure of the third rectifying tower is controlled to be 0.10MPa, the temperature of the kettle of the third rectifying tower correspondingly drops to 90 ℃, the pressure of the top of the second rectifying tower is controlled to be 0.2MPa, the temperature of the top of the second rectifying tower correspondingly rises to 100 ℃, and the temperature of the third rectifying tower is lower than that of the second rectifying tower, so that the reboiler 6 of the second rectifying tower cannot provide heat for the second rectifying tower, and the system cannot normally operate.
The steps and the process conditions are the same as those in the example 7, the pressure of the third rectifying tower is controlled to be 0.1MPa, the temperature of the kettle of the third rectifying tower is correspondingly reduced to 90 ℃, the pressure of the top of the fourth rectifying tower is controlled to be 0.060MPa, the temperature of the top of the fourth rectifying tower 4 is correspondingly reduced to 90 ℃, and the temperature difference between the third rectifying tower and the fourth rectifying tower is not in the range of 10-40 ℃ under the same temperature, so that the fourth rectifying tower reboiler 9 cannot provide heat for the fourth rectifying tower, and the system cannot normally operate.
The steps and the process conditions are the same as those in the example 7, the pressure of the third tower of the rectifying tower is controlled to be 0.38MPa, the temperature of the kettle of the third tower of the rectifying tower correspondingly rises to 130 ℃, the pressure of the top of the fourth tower of the rectifying tower is controlled to be 0.05MPa, the temperature of the top of the fourth 4 tower of the rectifying tower correspondingly falls to 80 ℃, the temperature difference of the kettle of the third tower of the rectifying tower and the kettle of the fourth tower of the rectifying tower is 50 ℃ due to the conditions, the temperature of the gas phase at the top of the third tower of the rectifying tower is not higher than the temperature of the kettle of the fourth tower of the rectifying tower by 10-40 ℃, and the reboiler 9 of the fourth tower of the rectifying tower supplies too much heat to the fourth tower of the rectifying tower, so that the system cannot normally operate.
The steps and the process conditions are the same as those of the example 7, the pressure of the third rectifying tower is controlled to be 0.10MPa, the temperature of the kettle of the third rectifying tower correspondingly decreases to 90 ℃, the pressure of the top of the fourth rectifying tower is controlled to be 0.15MPa, the temperature of the top of the fourth rectifying tower 4 correspondingly increases to 100 ℃, and as the temperature of the third rectifying tower is lower than that of the fourth rectifying tower, a reboiler 9 of the fourth rectifying tower cannot provide heat for the fourth rectifying tower, and the system cannot normally operate.
Claims (20)
1. The energy-saving process for separating the crude monomers is characterized by comprising the following steps of:
(1) feeding organosilicon crude monomers into a first rectifying tower 1, feeding gas-phase materials subjected to high boiling removal at the top of the first rectifying tower 1 into a third tower kettle reboiler 8 of the rectifying tower to serve as a heat source, condensing the gas-phase materials by the third tower kettle reboiler 8 of the rectifying tower, and feeding the gas-phase materials by a reflux pump 13 of the rectifying tower to serve as a second rectifying tower 2;
(2) the output from the second 2 tower bottom of the rectifying tower is conveyed by a second tower bottom liquid pump 16 of the rectifying tower to be used as the feed of a third rectifying tower 3 and a fourth rectifying tower 4.
2. The energy-saving process for separating crude monomers as claimed in claim 1, wherein the organosilicon crude monomers in step (1) are a mixture of methyl chlorosilane, and the mixture comprises 82-87% of dimethyl dichlorosilane, 5-9% of methyl chlorosilane, 2-5% of high-boiling residues and 4-7% of light components by mass percent.
3. The energy-saving process for separating crude monomer as claimed in claim 2, wherein the temperature at the top of the distillation column 1 in step (1) is controlled at 110-150 ℃ and the pressure at the top of the distillation column is controlled at 0.30-0.6MPa, preferably, the temperature at the top of the distillation column 1 is controlled at 120-145 ℃ and the pressure at the top of the distillation column is controlled at 0.35-0.5 MPa.
4. The energy-saving process for separating crude monomers according to claim 3, wherein in the step (1), the high-boiling gas phase material removed from the top of the rectifying tower I1 is completely fed into a rectifying tower III kettle reboiler 8 as a heat source.
5. The energy-saving crude monomer separation process according to claim 4, wherein 40-90% of the condensed product obtained in step (1) is returned to the top of the first rectification column 1 as a column reflux by a reflux pump 13 of the rectification column, and the rest of the condensed product is fed to the second rectification column 2.
6. The energy-saving process for separating crude monomers according to claim 4, wherein 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% of materials in volume fraction are returned to the top of the first rectifying tower 1 as tower reflux through a rectifying tower reflux pump 13 after being condensed by a rectifying tower three-tower kettle reboiler 8 in the step (1), and the corresponding rest is used as the feeding material of the second rectifying tower 2.
7. The energy-saving process for separating crude monomers as claimed in claim 1, wherein in the step (2), the temperature of the bottom of the rectifying tower 2 is controlled to be 80-100 ℃, the pressure of the tower is controlled to be 0.05-0.2MPa, and the temperature of the bottom of the rectifying tower 2 is controlled to be 85-95 ℃ as a preferred scheme.
8. The energy-saving process for separating crude monomers according to claim 7, wherein in the step (2), the second distillation tower 2 is used for extracting 50-80% of the crude monomers, and the crude monomers are conveyed to the third distillation tower 3 and the rest is conveyed to the fourth distillation tower 4 through the second distillation tower 2 and the liquid pump 16.
9. The energy-saving process for separating crude monomers according to claim 8, wherein in the step (2), the material extracted from the second 2 tower still of the rectification tower is conveyed by a liquid pump 16 of the second 2 tower still of the rectification tower for 50%, 55%, 60%, 65%, 70%, 75% and 80% of volume fraction to the third 3 rectification tower and the corresponding remaining material to the fourth 4 rectification tower.
10. The energy-saving process for separating the crude monomers as claimed in claim 9, wherein the gas phase at the top of the second rectifying tower 2 is condensed by the second rectifying tower condenser 7 and enters the second rectifying tower reflux tank 12, a part of the material in the second rectifying tower reflux tank 12 is conveyed by the second rectifying tower reflux pump 15 and returns to the top of the second rectifying tower 2 as tower reflux, and the other part of the extracted component 21 with the boiling point lower than 60 ℃ enters the subsequent rectifying tower for separation.
11. The energy-saving process for separating crude monomers as claimed in claim 10, wherein 70-99% of the material in the second reflux tank 12 of the rectification column is delivered by the reflux pump 15 of the rectification column 2 to return to the top of the rectification column 2, and the other part of the material is extracted to obtain the low boiling point component 21.
12. The energy-saving process for separating crude monomers according to claim 11, wherein the top temperature of the third 3 rectifying tower is controlled to be 90-120 ℃, and the top pressure is controlled to be 0.10-0.3 MPa; as a preferred scheme, the temperature of the third 3 tower bottom of the rectifying tower is controlled at 100 ℃, and the pressure at the top of the rectifying tower is controlled at 0.15 MPa.
13. The energy-saving process for separating crude monomer as claimed in claim 12, wherein the gas phase material at the top of the third rectifying tower 3 is delivered to the second still reboiler 6 of the rectifying tower in a volume fraction of 40-60%, and the rest is delivered to the fourth still reboiler 9 of the rectifying tower.
14. The energy-saving process for separating crude monomers as claimed in claim 12, wherein the gas phase material at the top of the third 3 rectifying tower is delivered to the second tower reboiler 6 of the rectifying tower in volume fractions of 40%, 45%, 50%, 55% and 60%, and the corresponding residual material is delivered to the fourth 4 tower reboiler 9 of the rectifying tower.
15. The energy-saving process for separating crude monomers as claimed in claim 14, wherein the condensate of the reboiler 6 at the second tower bottom of the rectification tower and the reboiler 9 at the fourth tower bottom of the rectification tower passes through the reflux pump 14 at the second coupling of the rectification tower and the reflux pump 17 at the fourth coupling of the rectification tower, part of the condensate returns to the top of the rectification tower 3, and part of the condensate is extracted as the mono-methyl trichlorosilane product 23 with a reflux ratio of 100-180.
16. The energy-saving process for separating crude monomer according to claim 15, wherein the temperature of the four 4-column bottom of the rectification column is controlled at 80-100 ℃, the pressure of the column bottom is controlled at 0.05-0.15MPa, and preferably, the temperature of the four 4-column bottom of the rectification column is controlled at 90 ℃, and the pressure of the column bottom is controlled at 0.1 MPa.
17. The energy-saving crude monomer separation process according to claim 16, wherein the gas phase at the top of the rectifying tower four 4 is condensed by the rectifying tower four condenser 10 and enters the rectifying tower four reflux tank 11, a part of the material in the rectifying tower four reflux tank 11 is conveyed by the rectifying tower four reflux pump 18 to return to the top of the rectifying tower four 4 as tower reflux, the other part of the material is extracted as a trichlorosilane product 25, and the bottom of the rectifying tower is extracted as a dimethyldichlorosilane product 24.
18. The energy-saving process for separating crude monomer as claimed in claim 17, wherein a portion of the material in the four-reflux tank 11 of the distillation column is transported to the top of the distillation column by the four-reflux pump 18 of the distillation column, and the other portion is used for producing a trichlorosilane product 25 with a reflux ratio of 100-180.
19. The energy-saving process for separating crude monomer according to any one of claims 1 to 18, wherein the temperature of the gas phase at the top of the first rectifying tower 1 is 10 to 40 ℃ higher than the temperature of the bottom of the third rectifying tower 3.
20. The energy-saving process for separating crude monomers as claimed in any one of claims 1 to 18, wherein the gas phase temperature at the top of the third rectifying tower 3 is 10-40 ℃ higher than the temperature at the bottom of the second rectifying tower 2 and the fourth rectifying tower 4.
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| CN101857606A (en) * | 2010-06-25 | 2010-10-13 | 天津大学 | Methyl chlorosilane parallel double-effect distillation method |
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| CN109897057A (en) * | 2019-02-01 | 2019-06-18 | 天津大学 | Use the device and method of multi-effect distillation technology separation organic silicon monomer methylchlorosilane |
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