CN116789568A - Method for reducing content of hydrolytic chlorine in toluene diisocyanate - Google Patents
Method for reducing content of hydrolytic chlorine in toluene diisocyanate Download PDFInfo
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- CN116789568A CN116789568A CN202310730693.9A CN202310730693A CN116789568A CN 116789568 A CN116789568 A CN 116789568A CN 202310730693 A CN202310730693 A CN 202310730693A CN 116789568 A CN116789568 A CN 116789568A
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- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 title claims abstract description 62
- 229910052801 chlorine Inorganic materials 0.000 title claims abstract description 62
- 239000000460 chlorine Substances 0.000 title claims abstract description 62
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 35
- 230000003301 hydrolyzing effect Effects 0.000 title claims abstract description 28
- 239000000463 material Substances 0.000 claims abstract description 16
- 238000011084 recovery Methods 0.000 claims abstract description 8
- 239000002994 raw material Substances 0.000 claims abstract description 6
- 238000010992 reflux Methods 0.000 claims description 20
- 239000011552 falling film Substances 0.000 claims description 5
- 239000010408 film Substances 0.000 claims 1
- 239000012530 fluid Substances 0.000 claims 1
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 230000007062 hydrolysis Effects 0.000 description 24
- 238000006460 hydrolysis reaction Methods 0.000 description 24
- 239000000047 product Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- 230000005611 electricity Effects 0.000 description 6
- 230000009467 reduction Effects 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 239000000498 cooling water Substances 0.000 description 3
- 239000012043 crude product Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000004508 fractional distillation Methods 0.000 description 2
- CKDWPUIZGOQOOM-UHFFFAOYSA-N Carbamyl chloride Chemical compound NC(Cl)=O CKDWPUIZGOQOOM-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/18—Separation; Purification; Stabilisation; Use of additives
- C07C263/20—Separation; Purification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for reducing the content of hydrolytic chlorine in toluene diisocyanate, which is characterized by adopting a modified self-regenerative rectification system, wherein the modified self-regenerative rectification system comprises a material rectification section and a heat recovery section, and specifically comprises the following steps of: (1) material rectifying section: introducing the raw materials into a rectifying tower for rectifying and separating, condensing the tower top steam by a condenser, and returning one part of the condensed steam into the tower and extracting the other part of condensed steam; one part of the tower kettle material enters a reboiler through a circulating pump, and enters the bottom of the modified rectifying tower after being vaporized, and the other part is extracted; (2) heat recovery section: the circulating working medium in the system is vaporized after the condenser absorbs the heat of the steam at the top of the tower, the temperature and the pressure are increased by the compressor, the circulating working medium enters the reboiler to heat the material at the bottom of the tower, and meanwhile, the circulating working medium is condensed and then enters the condenser to absorb heat. The TDI content of the tower top is more than or equal to 99.90 percent, the content of hydrolytic chlorine is less than or equal to 0.0015 percent, the rectification energy consumption is greatly reduced, the energy utilization rate is improved, the running cost is effectively reduced, and the economical efficiency is improved.
Description
Technical Field
The invention relates to a purification process of toluene diisocyanate, in particular to a method for reducing the content of hydrolytic chlorine in toluene diisocyanate.
Background
Toluene Diisocyanate (TDI) is mainly used for organic synthesis, foam plastic production, paint and chemical reagent, and has wide development prospect. At present, the TDI synthesis method mainly adopts a phosgene method with mature process and high economic benefit, but the method can generate carbamoyl chloride, dissolved phosgene, chlorinated aromatic hydrocarbon and other chlorine-containing impurities, so that chlorinated byproducts remain in the product. The content of the hydrolytic chlorine is an important index of the quality of the TDI product, and the content of the hydrolytic chlorine not only increases the subsequent purification difficulty, but also leads to the reduction of the reactivity, deepening of the color of the product and the reduction of the performance. Based on the effect of hydrolytic chlorine on TDI product performance, it is desirable to reduce the content of hydrolytic chlorine during the production process.
The existing research mainly reduces the content of hydrolytic chlorine in TDI crude products by methods of amine treatment, phosgene purification, rectification, adsorption and the like. For industrial production, the conditions of raw material treatment, technological process and the like are not easy to change, the rectification method can achieve better effect when used for treating products with high TDI content on a large scale, and the content of hydrolytic chlorine can be reduced by improving the rectification efficiency, so that the rectification is more suitable for industrial TDI production. In early days, during the period of the morsen, the TDI crude product is subjected to partial reflux, partial reflux plus fractional distillation and complete reflux plus fractional distillation, so that some hydrolytic chlorine in the crude product is decomposed into HCl gas and isocyanate, and the content of hydrolytic chlorine is reduced.Marcus Paul et al first performed a dephosgenation treatment to control the amount of phosgene to less than 2% by weight, then fractionally distilled to remove solvent and optional reaction residues to produce crude TDI containing less than 20% by weight solvent, and finally separated in a dividing wall rectifier to yield four product fractions having a TDI mass fraction of 99.5% and reduced to lower levels in both solvent quality and hydrolyzed chlorine content.
Although the rectifying method can achieve better effect in treating TDI hydrolysis chlorine wastewater, the researches generally have the problems of high energy consumption, low energy utilization rate and the like. At present, the energy consumed by the rectification process is about 60% of that consumed by all separation processes, but the energy utilization rate of the rectification process is only about 10%.
Disclosure of Invention
The invention aims to study the rectification process for reducing the hydrolysis chlorine in TDI by adopting a self-regenerative rectification system, and designs a reasonable rectification tower for reducing the hydrolysis chlorine content in TDI by optimizing the theoretical plate number, the feeding position and the reflux ratio, so that the hydrolysis chlorine content in the tower top is more than or equal to 99.90 percent and less than or equal to 0.0015 percent.
The invention further aims to provide a method for reducing the content of the hydrolysis chlorine in the TDI by using the self-regenerative rectification system, and the normal operation of the whole TDI degradation hydrolysis chlorine device can be maintained by only 192kW of electricity consumption, so that the operation cost can be reduced by 65.06% each year compared with the traditional process.
The technical scheme adopted for achieving the purpose of the invention is as follows:
the method for reducing the content of the hydrolytic chlorine in the toluene diisocyanate is characterized by adopting a self-regenerative rectification system, wherein the self-regenerative rectification system comprises a material rectification section and a heat recovery section, and specifically comprises the following steps of:
(1) Material rectifying section: introducing the raw materials into a rectifying tower for rectifying and separating, condensing the tower top steam by a condenser, and returning one part of the condensed steam into the tower and extracting the other part of condensed steam; one part of the tower kettle material enters a reboiler through a circulating pump, and enters the bottom of the modified rectifying tower after being vaporized, and the other part is extracted;
(2) Heat recovery section: the circulating working medium in the system is vaporized after the condenser absorbs the heat of the steam at the top of the tower, the temperature and the pressure are increased by the compressor, the circulating working medium enters the reboiler to heat the material at the bottom of the tower, and meanwhile, the circulating working medium is condensed and then enters the condenser to absorb heat.
Further, the theoretical plate number of the rectifying tower is 10-40.
Further, the feeding position of the rectifying tower is 5 th to 10 th tower plates.
Further, the reflux ratio of the rectifying tower is 0.5-1.0.
Further, the compressor is a double-screw compressor, and the circulating working medium is steam generated in the rectifying tower.
Further, the reboiler is a horizontal falling film reboiler.
Further, a circulating pump is arranged at the bottom of the rectifying tower, the tower bottom is pumped to the top inlet of the falling film type reboiler, vaporized in the reboiler, and enters the bottom of the rectifying tower from the bottom of the reboiler.
Compared with the prior art, the invention has the beneficial effects that:
(1) The self-backheating rectification system is adopted, so that the TDI content of the tower top is more than or equal to 99.90 percent, the hydrolysis chlorine content is less than or equal to 0.0015 percent, and the requirement of removing the hydrolysis chlorine of the TDI is met.
(2) The self-regenerative rectification system adopted in the research greatly reduces the rectification energy consumption, improves the energy utilization rate, effectively reduces the operation cost and improves the economy.
Drawings
FIG. 1 is a flow chart of a self-regenerative rectification system according to embodiment 1 of the present invention;
1-rectifying tower, 2-condenser, 3-compressor, 4-reboiler, 5-throttle regulating device and 6-circulating pump;
FIG. 2 is a graph showing the effect of feed position on overhead hydrolysis chlorine content in example 2 of the present invention;
FIG. 3 is a graph showing the effect of theoretical plate number on overhead hydrolysis chlorine content in example 3 of the present invention;
FIG. 4 is a graph showing the effect of reflux ratio on overhead hydrolysis chlorine content in example 4 of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
All numerical designations such as pH, temperature, length, flow, including ranges, are approximations. It is to be understood that the term "about" is not always preceded by the explicit recitation of all numerical designations. It is also to be understood that the agents described herein are merely examples and that equivalents thereof are known in the art, although not always explicitly recited.
Spatially relative terms, such as "upper," "lower," "left," "right," and the like, may be used in the embodiments for ease of description to describe one element or feature's relationship to another element or feature's illustrated in the figures. It will be understood that the spatial terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "under" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "lower" may encompass both an upper and lower orientation. The device may be otherwise positioned (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Example 1
The method for reducing the content of the hydrolytic chlorine in the toluene diisocyanate adopts a self-regenerative rectification system (shown in figure 1), wherein the self-regenerative rectification system comprises a material rectification section and a heat recovery section, and specifically comprises the following steps of:
(1) Material rectifying section: introducing the raw materials into a rectifying tower through a feed pump for rectifying separation, condensing the tower top steam through a condenser, and returning one part of the condensed steam into the tower and extracting the other part of condensed steam; one part of the tower kettle material enters a reboiler through a circulating pump, and enters the bottom of the modified rectifying tower after being vaporized, and the other part is extracted;
(2) Heat recovery section: the circulating working medium in the system is vaporized after the condenser absorbs the heat of the steam at the top of the tower, the temperature and the pressure are increased by the compressor, the circulating working medium enters the reboiler to heat the material at the bottom of the tower, and meanwhile, the circulating working medium is condensed and then enters the condenser to absorb heat.
Optionally, the raw materials in the embodiment are heavy components including TDI, hydrolytic chlorine and the like, the feeding temperature is 40 ℃, the pressure is 600kPa, the feeding flow is 10000kg/h, wherein the TDI flow is 9999kg/h, and the TDICL is 1kg/h.
Optionally, the water vapor amount at the top of the tower in the embodiment is 3011kg/h, the TDI content is more than or equal to 99.90%, and the hydrolysis chlorine content is less than or equal to 0.0015%.
Optionally, the compressor adopted in the embodiment is a double-screw compressor, the circulating working medium is steam generated in the rectifying tower, the inlet and outlet temperatures of the compressor are 140 ℃ and 166.3 ℃, and the inlet and outlet pressures are 360kPa and 720kPa, respectively.
Optionally, the reboiler of this embodiment is a horizontal falling film reboiler.
Optionally, a circulating pump is arranged at the bottom of the rectifying tower, the tower bottom is pumped to the top inlet of the falling film type reboiler, vaporized in the reboiler, and enters the bottom of the rectifying tower from the bottom of the reboiler.
Example 2
Based on the method and system described in example 1, this example optimizes the feed location.
Specifically, in this example, the theoretical plate number was set to 17, and the reflux ratio was set to 2, and as shown in FIG. 2, the influence of the feed position on the hydrolysis chlorine content at the top of the column was examined. In FIG. 2a, the overhead hydrolysis chlorine content showed a rapid decrease trend as the number of trays at the feed position increases at trays 2-4, and was reduced by 85.7% when the feed position was at tray 4, compared to tray 2. Further increases the number of tower plates at the feeding position, and the reduction trend of the hydrolysis chlorine content at the top of the tower is slow. Compared with the 4 th tower plate at the feeding position, when the 5 th tower plate at the feeding position is used, the content of the hydrolytic chlorine at the top of the tower is reduced by 59.1 percent. The method shows that the increase of the number of the tower plates at the feeding position can effectively reduce the content of hydrolytic chlorine at the top of the tower; as shown in FIG. 2b, the analysis was started from the 4 th tray at the feeding position, the content of the hydrolyzed chlorine at the top of the column was rapidly decreased from the 4 th tray to the 8 th tray, and compared with the 4 th tray at the feeding position, the content of the hydrolyzed chlorine at the top of the column was reduced by 97.1% when the 8 th tray was at the feeding position, at this time, the content of the hydrolyzed chlorine at the top of the column was less than 0.05ppm, and when the number of trays at the feeding position was 10, the content of the hydrolyzed chlorine at the top of the column was only 0.007ppm, and was 0 in the trend, and the number of trays at the feeding position was further increased, and the change of the content of the hydrolyzed chlorine at the top of the column was not significant. As described in the above analysis, the feed position is preferably 8 th to 15 th trays, more preferably 10 th trays.
Example 3
Based on the method and system described in example 1, this example optimizes the theoretical plate number.
Specifically, in this example, the feed position was set to be the 10 th block and the reflux ratio was set to be 2, and as shown in FIG. 3, the influence of the theoretical plate number on the content of hydrolyzed chlorine in the column top was examined. When the theoretical plate number is in the range of 5-8, the content of the hydrolytic chlorine at the top of the tower is rapidly reduced along with the increase of the theoretical plate number, the theoretical plate number is further increased, and the reduction amplitude of the hydrolytic chlorine at the top of the tower is reduced; when the theoretical plate number is 10, the content of the hydrolytic chlorine at the top of the tower is lower than 0.3ppm, and 15 theoretical plates are properly added, at the moment, the content of the hydrolytic chlorine at the top of the tower is at a low level (0.004 ppm), and the change of the content of the hydrolytic chlorine at the top of the tower is not obvious when the theoretical plate number is continuously added; the theoretical plate number is preferably 10 to 40, and more preferably 15 in view of the need to reduce the reflux ratio.
Example 4
Based on the method and system described in embodiment 1, this embodiment optimizes the reflux ratio.
Specifically, in this example, the feeding position was set to be the 10 th tray, the theoretical plate number was 15, and as shown in fig. 4, the influence of the reflux ratio on the hydrolysis chlorine content at the top of the column was examined. As shown in FIG. 4a, the reflux ratio was in the range of 0.1 to 0.4, and the overhead hydrolysis chlorine content decreased rapidly as the reflux ratio increased. When the reflux ratio was 0.4, the overhead hydrolysis chlorine content was reduced by 95.1% compared to 0.1. At a reflux ratio of 0.4, the overhead hydrolysis chlorine content was 3.9ppm. As shown in fig. 4b, the reduction of the overhead hydrolysis chlorine becomes smaller by further increasing the reflux ratio. When the reflux ratio was 1.0, the overhead hydrolysis chlorine was 0.004ppm, tending to 0. Thus, the reflux ratio is preferably 0.4 to 4, more preferably 1 in view of the complexity of hydrolyzing chlorine and the need to wet the filler.
Example 5
Based on the method and system described in examples 1-4, specifically, the present example sets the feeding position as the 10 th tray, the theoretical tray number as 15 trays, the feeding temperature as 40 ℃ and the pressure as 600kPa, the feeding flow as 10000kg/h, wherein the TDI flow as 9999kg/h, the TDICL as 1kg/h, the overhead temperature as 146.3 ℃ and the pressure as 4kPa after separation by the rectifying tower, the total mass flow of the TDI product as 9504kg/hr, the TDI split mass flow as 9504kg/hr, and the trace amount of hydrolyzed chlorine were obtained. The temperature of the tower bottom is 156.7 ℃, the pressure is 6kPa, the total mass flow of the TDI product is 496kg/hr, the TDI split mass flow is 495kg/hr, and the trace amount of the hydrolyzed chlorine is 1kg/hr. The tower top is basically free of hydrolytic chlorine, and the hydrolytic chlorine is in the tower bottom. The TDI content of the tower top meeting the requirement is more than or equal to 99.90 percent, and the content of hydrolytic chlorine is less than or equal to 0.0015 percent.
Example 6
Based on the method and system described in embodiments 1-5, in particular, the embodiment performs economic analysis on the self-regenerative rectification system, the design feed amount of the rectification tower is 10000kg/h, and the water vapor amount at the top of the rectification tower is 3011kg/h. The device can operate under the load of 60-120% of design capacity. According to the consumption quota of the self-backheating rectification system in table 1, the normal operation of the whole TDI degradation and hydrolysis chlorine device can be maintained only by 192kW of electricity consumption. According to the energy price: the price of industrial steam is 160 yuan/t, and the cooling water is 0.2 yuan/m 3 The electricity price was 0.7 yuan/degree, and the operating parameters in table 1, compare the economics of the self-regenerative rectification system with that of conventional rectification. According to GB/T50441-2007 petrochemical engineering design energy consumption calculation Standard: the energy conversion value (calculated by standard coal) of the steam is 103kg/t, the circulating water is 0.143kg/t, and the electricity is 0.371kg/kW.h. The economic comparison of the two is shown in Table 2, calculated as 8000 hours of annual working time. After the self-regenerative rectification technology is adopted to reduce the hydrolysis chlorine in TDI, the operation cost is reduced from 614.4 ten thousand yuan to 214.7 ten thousand yuan, the cost can be reduced by 65.06 percent each year, and great social and economic benefits are achieved.
Table 1 consumption quota for regenerative rectification system
The calculation process is as follows:
traditional rectification operation cost: (steam consumption 4.4t/h, circulating cooling water 320m 3/h):
steam consumption:
4.4t/h×160 yuan/t×8000 h/year= 563.2 ten thousand yuan/year;
circulating water consumption:
320m3/h x 0.2 yuan/ton x 8000 hours/year = 51.2 ten thousand yuan/year;
the traditional rectification is operated annually:
563.2 ten thousand yuan +51.2 ten thousand yuan = 614.4 ten thousand yuan
The annual operation cost of the self-regenerative rectification system is as follows:
electricity consumption:
192 x 0.7 yuan/degree x 8000 hours/year=107.5 ten thousand yuan;
circulating water consumption:
30m3/h×0.2 yuan/ton×8000 hours/year=4.8 ten thousand yuan/year;
steam consumption:
0.8t/h×160 yuan/ton×8000 hours/year=102.4 ten thousand yuan/year;
the annual operation cost of the self-regenerative rectification system is as follows:
107.5 ten thousand yuan +4.8 ten thousand yuan +102.4 ten thousand yuan = 214.7 ten thousand yuan
The annual operation cost which can be saved by adopting the self-regenerative rectification system is as follows:
614.4-214.7 ten thousand yuan = 399.7 ten thousand yuan, reduced by 65.06%.
TABLE 2 economic comparison of conventional rectification and self-regenerative rectification systems
| Index (I) | Traditional process | Self-backheating rectification process |
| Steam cost/ten thousand yuan | 563.2 | 102.4 |
| Cost of cooling water/ten thousand yuan | 51.2 | 4.8 |
| Electricity charge/ten thousand yuan | 0 | 107.5 |
| Totaling/ten thousand yuan | 614.4 | 214.7 |
The invention has proved that the high-TDI content product can achieve better effect by adopting the self-regenerative rectification method to treat the high-TDI content product on a large scale, and the hydrolysis chlorine content can be further reduced, the TDI quality is improved, the energy consumption is reduced, the energy utilization rate is improved, and the economy is improved by optimizing the optimal feeding position, the theoretical plate number, the reflux ratio and the like, so that the invention is more suitable for industrial application.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (7)
1. The method for reducing the content of the hydrolytic chlorine in the toluene diisocyanate is characterized by adopting a self-regenerative rectification system, wherein the self-regenerative rectification system comprises a material rectification section and a heat recovery section, and specifically comprises the following steps of:
(1) Material rectifying section: introducing the raw materials into a rectifying tower for rectifying and separating, condensing the tower top steam by a condenser, and returning one part of the condensed steam into the tower and extracting the other part of condensed steam; one part of the tower kettle material enters a reboiler through a circulating pump, and enters the bottom of the modified rectifying tower after being vaporized, and the other part is extracted;
(2) Heat recovery section: the circulating working medium in the system is vaporized after the condenser absorbs the heat of the steam at the top of the tower, the temperature and the pressure are increased by the compressor, the circulating working medium enters the reboiler to heat the material at the bottom of the tower, and meanwhile, the circulating working medium is condensed and then enters the condenser to absorb heat.
2. The method according to claim 1, wherein the theoretical plate number of the rectifying column is 10 to 40.
3. The method according to claim 1, wherein the rectifying column is fed at a position of 8 th to 15 th trays.
4. The method according to claim 1, wherein the reflux ratio of the rectifying column is 0.5 to 1.0.
5. The method of claim 1, wherein the compressor is a twin screw compressor and the circulating fluid is steam generated in the rectifying column.
6. The method of claim 1, wherein the reboiler is a horizontal drop-film reboiler.
7. The method according to claim 1, wherein a circulating pump is arranged at the bottom of the rectifying tower, the tower kettle is pumped to the top inlet of the falling film type reboiler, vaporized in the reboiler, and enters the bottom of the rectifying tower from the bottom of the reboiler.
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| CN206858467U (en) * | 2017-06-14 | 2018-01-09 | 天津如有科技有限公司 | Carbon 4 heat pump rectifying device |
| CN110156603A (en) * | 2019-04-12 | 2019-08-23 | 天津乐科节能科技有限公司 | A kind of method and device of dimethyl carbonate from backheat rectifying |
| CN214105865U (en) * | 2020-08-24 | 2021-09-03 | 常熟龙飞医药设备科技有限公司 | Heat pump rectifying device adopting working medium compression |
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