Energy-saving device for producing dimethyl carbonate by transesterification method

Abstract

The utility model discloses an energy-saving device for producing dimethyl carbonate by a transesterification method. Comprising a first tower (T-1101), a first tower reflux tank (V-1101), a first tower reboiler (E-1102), a first tower kettle pump (P-1102), a third tower (T-1301), a third tower reboiler (E-1302), a third tower condenser (E-1301), a third tower reflux tank (V-1301), a third tower reflux pump (P-1301), a third tower kettle pump (P-1302), a third tower vacuum pump (P-1303), a fourth tower feeding tank (V-1401), a fourth tower (T-1401), a fourth tower reflux tank (V-1401), a fourth tower reflux pump (P-1401), a fourth tower kettle pump (P-1402) and the like. The energy-saving device suitable for producing the dimethyl carbonate by the transesterification method can continuously and efficiently produce the dimethyl carbonate, so that steam and circulating water are greatly saved, and the aims of saving energy and reducing consumption are fulfilled.

Description

TECHNICAL FIELD

[0001] The utility model relates to the production technology field of dimethyl carbonate especially relates to a kind of energy-saving device for producing dimethyl carbonate by ester exchange method. BACKGROUND

[0002] Dimethyl carbonate is also named methyl carbonate, ethane carbonate, simply called DMC, dimethyl carbonate is a kind of non-toxic, environmental protection performance excellent, widely used chemical raw material, it is a kind of important organic synthesis intermediate, molecular structure contains carbonyl, methyl and methoxyl group and other functional groups, has multiple reaction performance, with the characteristics of safe, convenient, less pollution, easy transportation in production.DMC not only has little toxicity, also has the characteristics such as high flash point, low vapor pressure and high lower explosive limit in air, therefore is the green solvent that set clean and safety in one, is a kind of "green" chemical product with development prospect.

[0003] At present, domestic production dimethyl carbonate mainly is the production process of ester exchange method, this method usually carries out ester exchange reaction with propylene carbonate and methanol, generates corresponding dimethyl carbonate and propylene glycol.Ester exchange method has the advantages such as mild reaction condition, raw material is easy to get, by-product is little, but due to this method is to utilize the different azeotrope composition of DMC and methanol under different pressure, through rectification separates DMC and methanol, methanol is recycled in it, so energy consumption is high.

[0004] The energy-saving device of the utility model has the advantages that: utilize the temperature difference between four towers, one tower, three tower materials, reasonably carry out heat exchange, realize the multiple energy-saving of four towers, three towers and one tower. SUMMARY

[0005] The utility model solves the technical problem in providing a kind of energy-saving device of dimethyl carbonate production of ester exchange method, the energy-saving device of dimethyl carbonate provided in the application can effectively utilize the temperature difference between the gas phase material of one tower top and three tower kettle material, four tower top gas phase material and one tower kettle material and heat exchange, save steam and circulating water, reach the effect of energy saving. In view of this, the energy-saving device for producing dimethyl carbonate provided in the application includes: one tower (T-1101), one reflux tank (V-1101), one tower reboiler (E-1102), one tower kettle pump (P-1102), three towers (T-1301), three tower reboiler (E-1302), three tower condenser (E-1301), three reflux tanks (V-1301), three reflux pumps (P-1301), three tower kettle pumps (P-1302), three tower vacuum pumps (P-1303), N2 import valve group (1), four tower feeding tank (V-1402), four towers (T-1401), four reflux tanks (V-1401), four tower reboiler (E-1401), four reflux pumps (P-1401), four tower kettle pumps (P-1403), steam import valve group (2).The mixture of propylene carbonate, methanol and catalyst is connected to the feed end of column T-1101, the column T-1101 column bottom discharge is connected to the feed end of column column bottom pump P-1102, the column column bottom pump P-1102 discharge end is connected to the tube side feed end of column reboiler E-1102 and propylene glycol treatment system respectively, the column T-1101 overhead discharge end is connected to the shell side feed end of three column reboiler E-1302, the three column reboiler E-1302 shell side discharge end is connected to the column reflux tank feed end, the column T-1101 overhead gas phase material is used as heating medium to heat three column T-1301 through three column reboiler E-1302, N2 pipeline is connected to the column reflux tank V-1101, the column reflux tank V-1101 discharge end is connected to the four column feed tank V-1401 feed end and the middle upper section of column T-1101 respectively; the three column T-1301 column bottom discharge is connected to the tube side feed end of three column reboiler E-1302 and the feed end of three column column bottom pump P-1302 respectively, the three column column bottom pump P-1302 discharge end is connected to the middle lower section of column T-1101, the three column T-1301 overhead gas phase is connected to the shell side feed end of three column condenser E-1301, the three column condenser E-1301 shell side discharge end is connected to the three column reflux tank feed end, the three column reflux tank discharge end is connected to the three column reflux pump P-1301 feed end, the three column reflux pump discharge end is connected to the four column feed tank and the middle upper section of three column T-1301 respectively, the four column T-1401 column bottom discharge is connected to the four column column bottom pump P-1403 and the tube side feed end of four column reboiler E-1401 respectively, the four column column bottom pump P-1403 discharge end is connected to the DMC rectification system, the four column T-1401 overhead gas phase is connected to the shell side feed end of column reboiler E-1102, the column reboiler E-1102 shell side discharge end is connected to the four column reflux tank V-1401, the four column reflux tank discharge end is connected to the four column reflux pump feed end, the four column reflux pump discharge end is connected to the middle lower section of three column T-1301 and the middle upper section of four column T-1401 respectively.

[0006] The column T-1101 overhead is provided with pressure P1, and is set remote DCS automatic interlock control by N2 inlet valve group (1), the opening of N2 inlet valve group (1) controls the pressure of column T-1101 at 20KPaG-50KPaG, when the pressure of column T-1101 is lower than 20KPaG, then the opening of N2 inlet valve group (1) can be opened to make the pressure of column T-1101 rise, on the contrary, when the pressure of column T-1101 is higher than 50KPaG, then the opening of N2 inlet valve group (1) can be closed to make the pressure of column T-1101 drop, so as to control the temperature of column T-1101 overhead gas phase material, and make it reach the best heat exchange state with three column T-1301 bottom material.

[0007] The top of the three-tower (T-1301) is provided with a pressure (P3), and is provided with a remote DCS automatic interlocking control with a three-tower vacuum pump (P-1303), the three-tower vacuum pump (P-1303) controls the pressure (P3) of the top of the three-tower, the pressure of the top of the three-tower is controlled to be -60KPaG to -40KPaG, so as to control the temperature of the material in the kettle of the three-tower, and make the material in the kettle of the three-tower reach the optimal heat exchange state with the material in the top of the one-tower.

[0008] The opening degree of the steam inlet valve group (2) controls the pressure of the top of the four-tower (T-1401) to be 0.3MPaG to 0.6MPaG, when the pressure (P5) of the top of the four-tower is lower than 0.3MPaG, the opening degree of the steam inlet valve group (2) is increased, so as to increase the steam delivery amount, thereby increasing the pressure (P5) of the top of the four-tower, when the pressure (P5) of the top of the four-tower is higher than 0.6MPaG, the opening degree of the steam inlet valve group (2) is reduced, so as to reduce the steam delivery amount, thereby reducing the pressure (P5) of the top of the four-tower, the pressure of the top of the four-tower is controlled to be 0.3MPaG to 0.6MPaG, and the temperature of the gas phase material in the top of the four-tower meets the heat exchange requirement with the material in the kettle of the one-tower.

[0009] The utility model has the following advantages:

[0010] (1) the production pressure of each tower is controlled, so as to control the temperature of the material in each tower, heat exchange is carried out between the materials in each tower by utilizing the temperature difference, the amount of steam and circulating water is saved, and energy saving and consumption reduction are realized.

[0011] (2) the energy saving device adopts DCS automatic control, and the production operation is simplified. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is the device schematic drawing of the utility model.

[0013] Symbol explanation:

[0014] T-1101-one tower

[0015] V-1101-one reflux tank

[0016] P-1102-kettle pump of one tower

[0017] E-1102-reboiler of one tower

[0018] P1-top pressure of one tower

[0019] T1-top temperature of one tower

[0020] P2-reflux tank pressure

[0021] T-1301-three towers

[0022] E-1301 - Triple Column Condenser

[0023] E-1302 - Triple Column Reboiler

[0024] V-1301 - Triple Column Feed Tank

[0025] P-1303 - Triple Column Vacuum Pump

[0026] P-1301 - Triple Column Reflux Pump

[0027] P-1302 - Triple Column Kettle Pump

[0028] T3 - Triple Column Overhead Temperature

[0029] P3 - Triple Column Overhead Pressure

[0030] T4 - Triple Column Kettle Temperature

[0031] P4 - Triple Column Kettle Pressure

[0032] T-1401 - Quad Column

[0033] V-1402 - Quad Column Feed Tank

[0034] P-1402 - Quad Column Feed Pump

[0035] E-1401 - Quad Column Reboiler

[0036] V-1401 - Quad Column Reflux Tank

[0037] P-1401 - Quad Column Reflux Pump

[0038] P-1403 - Quad Column Kettle Pump

[0039] P5 - Quad Column Overhead Pressure

[0040] T5 - Quad Column Overhead Temperature DETAILED DESCRIPTION

[0041] The utility model is further described below in conjunction with examples, the following examples are intended to illustrate the utility model, rather than limit the utility model.

[0042] Aiming at the existing transesterification method production carbon dioxide methyl ester's process, the utility model provides an energy -conserving equipment for transesterification method production carbon dioxide methyl ester, including a tower (T-1101), a backflow tank (V-1101), a tower reboiler (E-1102), a tower kettle pump (P-1102), three towers (T-1301), three tower reboilers (E-1302), three tower condensers (E-1301), three backflow tanks (V-1301), three backflow pumps (P-1301), three tower kettle pumps (P-1302), three tower vacuum pumps (P-1303), N2 import valve group (1), four tower feed tank (V-1402), four towers (T-1401), four backflow tanks (V-1401), four tower reboilers (E-1401), four backflow pumps (P-1401), four tower kettle pumps (P-1403), steam import valve group (2).characterized in that the mixture liquid of propylene carbonate, methanol and catalyst is connected with the feed end of column (T-1101), the column (T-1101) column bottom discharge is connected with the feed end of column bottom pump (P-1102), the discharge end of column bottom pump (P-1102) is connected with the tube side feed end of column reboiler (E-1102) and propylene glycol treatment system respectively, the column top discharge end of column (T-1101) is connected with the shell side feed end of three column reboiler (E-1302), the shell side discharge end of three column reboiler (E-1302) is connected with the feed end of one reflux tank (V-1101), the column top gas phase material of column (T-1101) is used as heating medium to heat three column (T-1301) through three column reboiler (E-1302), N2 pipeline is connected with one reflux tank (V-1101), the discharge end of one reflux tank (V-1101) is connected with the feed end of four column feed tank and the middle upper section of column (T-1101) respectively; the column bottom discharge of three column (T-1301) is connected with the tube side feed end of three column reboiler (E-1302) and the feed end of three column bottom pump (P-1302) respectively, the discharge end of three column bottom pump (P-1302) is connected with the middle lower section of column (T-1101), the column top gas phase of three column (T-1301) is connected with the shell side feed end of three column condenser (E-1301), the shell side discharge end of three column condenser (E-1301) is connected with the feed end of three reflux tank (V-1301), the discharge end of three reflux tank (V-1301) is connected with the feed end of three reflux pump (P-1301), the discharge end of three reflux pump (P-1301) is connected with four column feed tank (V-1402) and the middle upper section of three column (T-1301) respectively, the column bottom discharge of four column (T-1401) is connected with four column bottom pump (P-1403) and the tube side feed end of four column reboiler (E-1401) respectively, the discharge end of four column bottom pump (P-1403) is connected with DMC rectification system, the column top gas phase of four column (T-1401) is connected with the shell side feed end of column reboiler (E-1102), the shell side discharge end of column reboiler (E-1102) is connected with four reflux tank (V-1401), the discharge end of four reflux tank (V-1401) is connected with the feed end of four reflux pump (P-1401), the discharge end of four reflux pump (P-1401) is connected with the middle lower section of three column (T-1301) and the middle upper section of four column (T-1401) respectively.

[0043] A tower (T-1101) is provided with a pressure (P1) at the top, and is remotely DCS automatically interlocked with the N2 import valve group (1) to control the opening of the N2 import valve group (1) to control the pressure of the tower at 20KPaG-50KPaG. When the pressure of the tower is lower than 20KPaG, the opening of the N2 import valve group (1) can be increased to increase the pressure of the tower. Conversely, when the pressure of the tower is higher than 50KPaG, the opening of the N2 import valve group (1) can be decreased to decrease the pressure of the tower, so as to control the temperature of the gaseous material at the top of the tower to reach the optimal heat exchange state with the material in the kettle of the third tower.

[0044] A tower (T-1101) is provided with a pressure (P1) at the top, and is remotely DCS automatically interlocked with the N2 import valve group (1) to control the opening of the N2 import valve group (1) to control the pressure of the tower at 20KPaG-50KPaG. When the pressure of the tower is lower than 20KPaG, the opening of the N2 import valve group (1) can be increased to increase the pressure of the tower. Conversely, when the pressure of the tower is higher than 50KPaG, the opening of the N2 import valve group (1) can be decreased to decrease the pressure of the tower, so as to control the temperature of the gaseous material at the top of the tower to reach the optimal heat exchange state with the material in the kettle of the third tower.

[0045] The opening of the steam import valve group (2) is controlled to control the pressure of the fourth tower (T-1401) at 0.3MPaG-0.6MPaG. When the pressure (P5) of the top of the fourth tower is lower than 0.3MPaG, the opening of the steam import valve group (2) can be increased to increase the steam delivery, so as to increase the pressure (P5) of the top of the fourth tower. Conversely, when the pressure (P5) of the top of the fourth tower is higher than 0.6MPaG, the opening of the steam import valve group (2) can be decreased to decrease the steam delivery, so as to decrease the pressure (P5) of the top of the fourth tower. The pressure of the top of the fourth tower is controlled at 0.3MPaG-0.6MPaG to control the temperature of the gaseous material at the top of the fourth tower to exchange heat with the material in the kettle of the first tower.

[0046] For the device of 30,000 tons of dimethyl carbonate produced by ester exchange method per year, the test results show that, in 6 months, the dimethyl carbonate produced by the energy-saving device provided by the utility model can save 45% of steam and 56% of circulating water compared with the traditional device of producing dimethyl carbonate by using steam as a heating heat source and circulating water as a cooling medium.

[0047] The above embodiment is only one implementation form of the energy-saving device for producing dimethyl carbonate by ester exchange method, and other deformations of the scheme provided by the utility model, increase or decrease the components or steps, or apply the utility model to the similar technical field of the utility model, all belong to the protection scope of the utility model.

Claims

1. An energy saving device for the production of dimethyl carbonate by transesterification comprising: One tower (T-1101), one backflow tank (V-1101), one tower reboiler (E-1102), one tower kettle pump (P-1102), three towers (T-1301), three tower reboiler (E-1302), three tower condenser (E-1301), three backflow tanks (V-1301), three backflow pumps (P-1301), three tower kettle pumps (P-1302), three tower vacuum pumps (P-1303), N2 inlet valve group (1), four tower feed tank (V-1402), four tower (T-1401), four backflow tank (V-1401), four tower reboiler (E-1401), four backflow pump (P-1401), four tower kettle pump (P-1403), steam inlet valve group (2); characterized in that the mixed liquid of propylene carbonate, methanol and catalyst is connected with the feed end of the one tower (T-1101), the one tower (T-1101) kettle discharge is connected with the feed end of the one tower kettle pump (P-1102), the discharge end of the one tower kettle pump (P-1102) is respectively connected with the tube side feed end of the one tower reboiler (E-1102) and the propylene glycol treatment system, the one tower (T-1101) overhead discharge end is connected with the shell side feed end of the three tower reboiler, the shell side discharge end of the three tower reboiler (E-1302) is connected with the feed end of the one backflow tank (V-1101), the N2 pipeline is connected with the one backflow tank (V-1101), the discharge end of the one backflow tank (V-1101) is respectively connected with the feed end of the four tower feed tank (V-1402) and the middle upper section of the one tower (T-1101), the three tower (T-1301) kettle discharge is respectively connected with the tube side feed end of the three tower reboiler (E-1302) and the feed end of the three tower kettle pump (P-1302), the discharge end of the three tower kettle pump (P-1302) is connected with the middle lower section of the one tower (T-1101), the three tower (T-1301) overhead gas phase is connected with the shell side feed end of the three tower condenser (E-1301), the shell side discharge end of the three tower condenser (E-1301) is connected with the feed end of the three backflow tank, the discharge end of the three backflow tank is connected with the feed end of the three backflow pump (P-1301), the discharge end of the three backflow pump is respectively connected with the feed end of the four tower feed tank and the middle upper section of the three tower (T-1301), the four tower (T-1401) kettle discharge is respectively connected with the four tower kettle pump (P-1403) and the tube side feed end of the four tower reboiler (E-1401), the discharge end of the four tower kettle pump (P-1403) is connected with the DMC rectification system, the four tower (T-1401) overhead gas phase is connected with the shell side feed end of the one tower reboiler (E-1102), the shell side discharge end of the one tower reboiler (E-1102) is connected with the four backflow tank (V-1401), the discharge end of the four backflow tank is connected with the feed end of the four backflow pump, the discharge end of the four backflow pump is respectively connected with the middle lower section of the three tower (T-1301) and the middle upper section of the four tower (T-1401).

2. The energy saving device for producing dimethyl carbonate by transesterification according to claim 1, wherein The temperature difference between the one tower overhead gas phase material and the three tower kettle material is utilized, and the one tower overhead gas phase material is used as the heating medium of the three tower reboiler (E-1302).

3. The energy saving device for producing dimethyl carbonate by transesterification according to claim 1, wherein N2 import valve group (1) and a tower top pressure (P1) set remote DCS automatic interlock control, using a tower top pressure (P1) control N2 import valve group (1).

4. The energy saving device for producing dimethyl carbonate by transesterification according to claim 1, wherein Three tower vacuum pump (P-1303) and three tower top pressure (P3) set remote DCS automatic interlock control, using three tower vacuum pump frequency conversion operation control three tower top pressure (P3).

5. The energy saving device for producing dimethyl carbonate by transesterification according to claim 1, wherein Using four tower top gas phase material and a tower kettle material temperature difference, heat exchange.

6. The energy saving device for producing dimethyl carbonate by transesterification according to claim 1, wherein Steam import valve group (2) and four tower top pressure (P5) set remote DCS automatic interlock control, using four tower top pressure (P5) control steam import valve group (2).

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