Process for producing amine ether by using sensible heat of recovered DEA

Abstract

The invention relates to the field of amine ether synthesis, in particular to a process for producing amine ether by using sensible heat of recovered DEA, which comprises the following steps: rectifying and separating crude amine ether, condensing the generated DEA gas to be 10-30 DEG C lower than the DEA gas temperature to obtain high-temperature DEA, carrying out gas-liquid separation on the high-temperature DEA, and then entering an amine ether synthesis process, according to the present invention, the feeding is stopped in the amine ether synthesis process or the high temperature DEA with the excessive normal production is transferred into the DEA raw material tank, such that the comprehensive application of the heat balance and the material balance in the pretilachlor intermediate amine ether production process is achieved, the problems of dual energy waste and operation time prolonging in the existing process are overcome, the cost is reduced, the efficiency is improved, and the actual production requirement is well met.

Description

Technical Field

[0001] The invention relates to the field of amine ether synthesis, in particular to a process for producing amine ether by utilizing the sensible heat of recovered DEA. Background Art

[0002] In the production process of the intermediate amine ether of pretilachlor, it is necessary to go through the steps of amine ether synthesis, dehydration, and refining. 2-Chloroethyl propyl ether and excess DEA are used to synthesize 2,6-diethyl-N-(2-propoxyethyl)aniline (amine ether) at normal pressure and 160℃~185℃; then the synthetic liquid containing 30% amine ether (the rest is 65~68% DEA and a small amount of impurities) is washed with water and dehydrated; the dehydrated synthetic liquid is then distilled and separated at 200℃~250℃ (tower bottom temperature), and then DEA is obtained at the top of the DEA tower, and amine ether is obtained at the top of the amine ether tower. At present, the outlet gas at the top of the DEA tower in production is cooled to 40℃~45℃ by circulating water condensation through the DEA tower top condenser and enters the DEA reflux tank. Part of it is refluxed into the DEA tower through the DEA reflux pump, and the other part is transferred to the DEA circulation tank by the DEA extraction pump for use in amine ether synthesis. Since the outlet temperature of the DEA tower top is 130℃~145℃, the amine ether synthesis temperature is 160℃~185℃. After the outlet gas of the DEA tower top is condensed and cooled to 40℃~45℃ DEA, the amine ether synthesis is carried out, and the DEA at 40℃~45℃ needs to be heated to 160℃~185℃. This heating after cooling down causes double waste of energy and extended operation time. A method for producing 2,6-diethyl-N-(2-propoxyethyl)aniline, an intermediate of pretilachlor, disclosed in a Chinese patent (publication number CN104478741A) mainly improves the utilization rate of raw materials by optimizing the acid binding agent, but it is essentially a laboratory production process, which cannot solve the problem that heat balance and material balance cannot be achieved simultaneously in the actual industrial production of amine ether. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a process for producing amine ethers by utilizing the sensible heat of recovered DEA, realizing the comprehensive application of heat balance and material balance in the production process of pretilachlor intermediate amine ether, overcoming the problems of double energy waste and prolonged operation time in the existing process, reducing costs and increasing efficiency, and better meeting the needs of actual production.

[0004] On one hand, the present invention provides a process for producing amine ethers by utilizing the sensible heat of recovered DEA, which comprises at least the following steps: crude amine ether is subjected to rectification and separation, the generated DEA gas is condensed to a temperature 10-30°C lower than the temperature of the DEA gas to obtain high-temperature DEA, the high-temperature DEA is subjected to gas-liquid separation and then enters the amine ether synthesis process, and the high-temperature DEA that stops feeding or is in excess of normal production in the amine ether synthesis process is transferred to a DEA raw material tank.

[0005] Preferably, the process for producing amine ethers by utilizing the sensible heat of recovered DEA comprises at least the following steps:

[0006] (1) After the crude amine ether is pumped into a DEA tower for distillation separation, the amine ether is pumped from the DEA tower kettle into the amine ether tower via an amine ether tower feed pump; the DEA gas enters a DEA tower top condenser from the top of the DEA tower;

[0007] (2) DEA gas enters the DEA top condenser from the top of the DEA tower and is condensed and cooled by a circulating heat transfer carrier to a temperature 10-30°C lower than the outlet gas temperature of the top of the DEA tower to obtain high-temperature DEA. The high-temperature DEA enters the gas-liquid separator for gas-liquid separation. The gas after gas-liquid separation enters the gas cooler for secondary condensation separation. The liquid after secondary condensation separation enters the gas-liquid separator for gas-liquid separation. The liquid after gas-liquid separation overcomes the atmospheric leg and enters the DEA hot material tank.

[0008] (3) When the liquid in the gas-liquid separator enters the DEA hot material tank, the room temperature DEA in the DEA raw material tank is sent to the top of the DEA tower through the DEA reflux pump for reflux to maintain the stability of the temperature at the top of the DEA tower and the balance of the DEA amount in the system;

[0009] (4) The hot DEA material in the DEA hot material tank enters the amine ether synthesis kettle and is mixed with the chloroether in the amine ether synthesis kettle. After the temperature is raised, an amine ether synthesis reaction is carried out to obtain amine ether.

[0010] As a preferred technical solution, the crude amine ether is synthesized with 2-chloroethyl propyl ether and excess DEA under normal pressure and 160°C to 185°C.

[0011] Preferably, the crude amine ether comprises 20-40% by weight of amine ether, 60-70% by weight of DEA (DEA), and the remainder of impurities.

[0012] As a preferred technical solution, the circulating heat-conducting carrier in step (1) is obtained by the following method: the low-temperature heat-conducting carrier enters the DEA tower top condenser through the heat-conducting carrier circulating pump, the outlet gas at the DEA tower top is condensed and then enters the heat-conducting carrier cooler, and then enters the heat-conducting carrier circulating pump after being cooled by circulating water to obtain the circulating heat-conducting carrier.

[0013] As a preferred technical solution, in step (1), the top temperature of the DEA tower is 130-145°C.

[0014] As a preferred technical solution, in step (1), the top pressure of the DEA tower is -0.08 to -0.099 MPa.

[0015] As a preferred technical solution, the circulating heat-conducting carrier in step (2) is selected from one of heat-conducting oil, water, and metal salt water solution.

[0016] As a preferred technical solution, the temperature of the high-temperature DEA in step (2) is ≤125°C, preferably 115-125°C, and most preferably 120-125°C.

[0017] As a preferred technical solution, in step (2), the temperature of the high-temperature DEA is controlled by controlling the opening of the heat transfer medium regulating valve through a regulating valve interlock, thereby controlling the amount of circulating heat transfer medium entering the DEA tower top condenser to ensure the temperature of the high-temperature DEA.

[0018] As a preferred technical solution, in step (3), the top temperature of the DEA tower is 130-145°C.

[0019] As a preferred technical solution, in step (4), the temperature of the hot DEA material after entering the amine ether synthesis kettle and mixing with the chloroether in the amine ether synthesis kettle is 100-110°C.

[0020] The present invention optimizes the process design and condenses the DEA gas at 130℃~145℃ into high-temperature DEA slightly lower than the temperature through secondary heat exchange for amine ether synthesis production, which can reduce the amount of natural gas required to be burned for heating the room-temperature DEA during the amine ether synthesis process, saving 112.5Nm of natural gas. 3 / sky.

[0021] Furthermore, the present invention is designed to send the room-temperature DEA in the DEA raw material tank to the top of the DEA tower for reflux through a DEA reflux pump while the liquid in the gas-liquid separator enters the DEA hot material tank. The recovered high-temperature DEA is used as a feed for amine ether synthesis. The high-temperature DEA produced in excess of normal production due to the cessation of feed in the amine ether synthesis process is returned to the raw material tank to meet the material balance of the entire system.

[0022] Based on the production process optimized by the present invention, the amine ether synthesis process uses the recycled high-temperature DEA (heating to the reaction temperature of 160°C to 185°C in about 2 hours), which can shorten the reaction time by about 3 hours compared with the original use of room-temperature DEA (heating to the reaction temperature of 160°C to 185°C in about 5 hours), and improve the synthesis production efficiency by about 15%, thereby greatly improving the production efficiency.

[0023] In addition, the process for producing amine ethers by utilizing the sensible heat of recovered DEA provided by the present invention can be analogized to the synthesis process of other pesticide intermediates, wherein the outlet gas of a heating and separation system such as a distillation tower and a distillation kettle is condensed and cooled to a high-temperature material slightly lower than the outlet gas temperature of the tower top, and is used for production in the previous synthesis process to save heat energy; then, the room temperature raw material is used as the reflux liquid, and the recovered high-temperature raw material is used for production in the previous synthesis process to meet the material balance of the entire system.

[0024] Beneficial Effects

[0025] 1. The present invention provides a process for producing amine ethers by utilizing the sensible heat of recovered DEA, realizing the comprehensive application of heat balance and material balance in the production process of pretilachlor intermediate amine ether, overcoming the problems of double energy waste and prolonged operation time in the existing process, reducing costs and increasing efficiency, and better meeting the needs of actual production.

[0026] 2. The present invention optimizes the process design and condenses the DEA gas at 130℃~145℃ into high-temperature DEA slightly lower than this temperature for amine ether synthesis production through secondary heat exchange, which can reduce the amount of natural gas burned for heating the room temperature DEA in the amine ether synthesis process, saving 112.5Nm of natural gas. 3 / sky.

[0027] 3. The present invention is designed to allow the liquid in the gas-liquid separator to enter the DEA hot material tank while sending the room-temperature DEA in the DEA raw material tank to the top of the DEA tower for reflux through a DEA reflux pump. The recovered high-temperature DEA is used as a feed for amine ether synthesis. The high-temperature DEA that is in excess of normal production due to the cessation of feeding in the amine ether synthesis process is returned to the raw material tank to meet the material balance of the entire system.

[0028] 4. Based on the production process optimized by the present invention, the amine ether synthesis process uses the recycled high-temperature DEA (heating to the reaction temperature of 160°C to 185°C in about 2 hours), which can shorten the reaction time by about 3 hours compared with the original use of room-temperature DEA (heating to the reaction temperature of 160°C to 185°C in about 5 hours), and improve the synthesis production efficiency by about 15%, thereby greatly improving the production efficiency.

[0029] 5. The process for producing amine ethers by utilizing the sensible heat of recovered DEA provided by the present invention can be analogized to the synthesis process of other pesticide intermediates. The outlet gas of the heating and separation system such as the distillation tower and the distillation kettle is condensed and cooled to a high-temperature material slightly lower than the outlet gas temperature of the tower top, and is used for the production of the previous synthesis process to save heat energy; then, the room temperature raw material is used as the reflux liquid, and the recovered high-temperature raw material is used for the production of the previous synthesis process to meet the material balance of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The process flow chart for producing amine ethers by utilizing the sensible heat of recovered DEA provided in Examples 1 and 2, wherein: DEA tower T101, amine ether tower feed pump P104, DEA tower top condenser E102, gas cooler E103, gas-liquid separator V101, DEA hot material tank V102, DEA raw material tank V103, regulating valve TV / P103, heat transfer carrier regulating valve TIC / V101.

[0031] Figure 2The conventional amine ether production process flow chart provided for comparative examples 1 and 2 includes: DEA tower T101, DEA tower top condenser E102, and DEA extraction pump P102. DETAILED DESCRIPTION

[0032] Example 1

[0033] See also Figure 1 Embodiment 1 of the present invention provides a process for producing amine ethers by utilizing the sensible heat of recovered DEA, comprising the following steps:

[0034] (1) After the crude amine ether is pumped into the DEA tower T101 for distillation separation, the amine ether is pumped from the bottom of the DEA tower T101 into the amine ether tower via the amine ether tower feed pump P104; the DEA gas enters the DEA tower top condenser E102 from the top of the DEA tower T101;

[0035] (2) DEA gas enters the DEA top condenser E102 from the top of the DEA tower T101, and is condensed and cooled by a circulating heat transfer medium to obtain high-temperature DEA. The high-temperature DEA enters the gas-liquid separator V101 for gas-liquid separation. The gas after gas-liquid separation enters the gas cooler E103 for secondary condensation separation. The liquid after secondary condensation separation enters the gas-liquid separator V101 for gas-liquid separation. The liquid after gas-liquid separation overcomes the atmospheric leg and enters the DEA hot material tank V102.

[0036] (3) While the liquid in the gas-liquid separator V101 enters the DEA hot material tank V102, the room temperature DEA in the DEA raw material tank V103 is sent to the top of the DEA tower T101 through the DEA reflux pump P101 for reflux, so as to maintain the stability of the top temperature of the DEA tower T101 and the balance of the DEA amount in the system;

[0037] (4) The hot DEA material in the DEA hot material tank V102 enters the amine ether synthesis kettle and is mixed with the chloroether in the amine ether synthesis kettle. The temperature is then raised to carry out an amine ether synthesis reaction to obtain amine ether.

[0038] The crude amine ether is synthesized by using 2-chloroethyl propyl ether and excess DEA under normal pressure and 170°C.

[0039] The crude amine ether comprises 30% by weight of amine ether, 69% by weight of DEA (2,6-diethylaniline) and the remainder of impurities.

[0040] The circulating heat-conducting carrier in step (1) is obtained in the following manner: the low-temperature heat-conducting carrier enters the DEA tower top condenser through the heat-conducting carrier circulating pump, the outlet gas from the DEA tower top is condensed and then enters the heat-conducting carrier cooler, and then enters the heat-conducting carrier circulating pump after being cooled by circulating water to obtain the circulating heat-conducting carrier.

[0041] In the step (1), the top temperature of the DEA tower is 135°C.

[0042] In the step (1), the top pressure of the DEA tower is -0.099 MPa.

[0043] The circulating heat-conducting carrier in step (2) is heat-conducting oil.

[0044] In step (2), the temperature of the high-temperature DEA is 120° C., and at this time, a small amount of liquid refluxes from the gas cooler E103 (indicating that the condensate at this temperature will not boil again).

[0045] In step (2), the temperature of the high-temperature DEA is controlled by the regulating valve TV / P103 to interlock the opening of the heat transfer medium regulating valve TIC / V101, thereby controlling the amount of circulating heat transfer medium entering the DEA tower top condenser to ensure the temperature of the high-temperature DEA.

[0046] In the step (3), the top temperature of the DEA tower is 135°C.

[0047] In the step (4), the temperature of the hot DEA material after entering the amine ether synthesis kettle and mixing with the chloroether in the amine ether synthesis kettle is 107° C., and the time required to heat up to 170° C. is 2.2 hours.

[0048] Example 2

[0049] See also Figure 1 Embodiment 2 of the present invention provides a process for producing amine ethers by utilizing the sensible heat of recovered DEA, comprising the following steps:

[0050] (1) After the crude amine ether is pumped into the DEA tower T101 for distillation separation, the amine ether is pumped from the bottom of the DEA tower T101 into the amine ether tower via the amine ether tower feed pump P104; the DEA gas enters the DEA tower top condenser E102 from the top of the DEA tower T101;

[0051] (2) DEA gas enters the DEA top condenser E102 from the top of the DEA tower T101, and is condensed and cooled by a circulating heat transfer medium to obtain high-temperature DEA. The high-temperature DEA enters the gas-liquid separator V101 for gas-liquid separation. The gas after gas-liquid separation enters the gas cooler E103 for secondary condensation separation. The liquid after secondary condensation separation enters the gas-liquid separator V101 for gas-liquid separation. The liquid after gas-liquid separation overcomes the atmospheric leg and enters the DEA hot material tank V102.

[0052] (3) While the liquid in the gas-liquid separator V101 enters the DEA hot material tank V102, the room temperature DEA in the DEA raw material tank V103 is sent to the top of the DEA tower T101 through the DEA reflux pump P101 for reflux, so as to maintain the stability of the top temperature of the DEA tower T101 and the balance of the DEA amount in the system;

[0053] (4) The hot DEA material in the DEA hot material tank V102 enters the amine ether synthesis kettle and is mixed with the chloroether in the amine ether synthesis kettle. The temperature is then raised to carry out an amine ether synthesis reaction to obtain amine ether.

[0054] The crude amine ether is synthesized by using 2-chloroethyl propyl ether and excess DEA under normal pressure and 170°C.

[0055] The crude amine ether comprises 30% by weight of amine ether, 69% by weight of DEA (2,6-diethylaniline) and the remainder of impurities.

[0056] The circulating heat-conducting carrier in step (1) is obtained in the following manner: the low-temperature heat-conducting carrier enters the DEA tower top condenser through the heat-conducting carrier circulating pump, the outlet gas from the DEA tower top is condensed and then enters the heat-conducting carrier cooler, and then enters the heat-conducting carrier circulating pump after being cooled by circulating water to obtain the circulating heat-conducting carrier.

[0057] In the step (1), the top temperature of the DEA tower is 135°C.

[0058] In the step (1), the top pressure of the DEA tower is -0.099 MPa.

[0059] The circulating heat-conducting carrier in step (2) is heat-conducting oil.

[0060] In step (2), the temperature of high-temperature DEA is 130°C, and at this time, a large amount of liquid refluxes from the gas cooler E103 (indicating that the condensate at this temperature will boil a second time, causing unstable pressure at the top of the tower. After lowering the condensate temperature to 125°C, the amount of liquid reflux from the gas cooler E103 gradually decreases, and the pressure tends to be stable).

[0061] In step (2), the temperature of the high-temperature DEA is controlled by the regulating valve TV / P103 to interlock the opening of the heat transfer medium regulating valve TIC / V101, thereby controlling the amount of circulating heat transfer medium entering the DEA tower top condenser to ensure the temperature of the high-temperature DEA.

[0062] In the step (3), the top temperature of the DEA tower is 135°C.

[0063] In the step (4), the temperature of the hot DEA material after entering the amine ether synthesis kettle and mixing with the chloroether in the amine ether synthesis kettle is 110° C., and the time required to heat up to 170° C. is 2 hours.

[0064] Comparative Example 1

[0065] See also Figure 2Comparative Example 1 of the present invention provides a traditional amine ether production process, which specifically comprises the following steps: crude amine ether is pumped into a distillation tower (DEA tower T101) at a required flow rate, and the tower top temperature TIC / T101 is 135°C (tower top pressure -0.099MPa), and the tower top DEA gas enters the DEA tower top condenser E102, and a part of the DEA with a temperature of 45°C after condensation and cooling by circulating water is refluxed, and a part is extracted to the amine ether synthesis kettle through the DEA extraction pump P102, and the temperature after mixing with the chloroether in the amine ether synthesis kettle is 38°C, and then the temperature is increased to react, and the temperature is increased to 170°C for 5.2h to carry out amine ether synthesis reaction to obtain amine ether.

[0066] Comparative Example 2

[0067] See also Figure 2 Comparative Example 2 of the present invention provides a traditional amine ether production process, which specifically comprises the following steps: crude amine ether is pumped into a distillation tower (DEA tower T101) at a required flow rate, and the tower top temperature TIC / T101 is 135°C (tower top pressure -0.099MPa), and the tower top DEA gas enters the DEA tower top condenser E102, and a part of the DEA with a temperature of 52°C after condensation and cooling by circulating water is refluxed, and a part is extracted to the amine ether synthesis kettle through the DEA extraction pump P102, and the temperature after mixing with the chloroether in the amine ether synthesis kettle is 43°C, and then the temperature is increased to react, and the temperature is increased to 170°C for 4.8h to carry out amine ether synthesis reaction to obtain amine ether.

Claims

1. A process for producing amine ethers by utilizing the sensible heat of recovered DEA, characterized in that: At least the following steps are included: The crude amine ether is distilled and separated, and the generated DEA gas is condensed to a temperature 10-30°C lower than the DEA gas temperature to obtain high-temperature DEA. The high-temperature DEA enters the amine ether synthesis process after gas-liquid separation. The high-temperature DEA that stops feeding or is in excess of normal production in the amine ether synthesis process is transferred to the DEA raw material tank.

2. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 1, characterized in that: At least the following steps are included: (1) After the crude amine ether is pumped into a DEA tower for distillation separation, the amine ether is pumped from the DEA tower kettle into the amine ether tower via an amine ether tower feed pump; DEA gas enters the DEA top condenser from the top of the DEA tower; (2) DEA gas enters the DEA top condenser from the top of the DEA tower and is condensed and cooled by a circulating heat transfer carrier to a temperature 10-30°C lower than the outlet gas temperature of the top of the DEA tower to obtain high-temperature DEA. The high-temperature DEA enters the gas-liquid separator for gas-liquid separation. The gas after gas-liquid separation enters the gas cooler for secondary condensation separation. The liquid after secondary condensation separation enters the gas-liquid separator for gas-liquid separation. The liquid after gas-liquid separation overcomes the atmospheric leg and enters the DEA hot material tank. (3) When the liquid in the gas-liquid separator enters the DEA hot material tank, the room temperature DEA in the DEA raw material tank is sent to the top of the DEA tower through the DEA reflux pump for reflux to maintain the stability of the temperature at the top of the DEA tower and the balance of the DEA amount in the system; (4) The hot DEA material in the DEA hot material tank enters the amine ether synthesis kettle and is mixed with the chloroether in the amine ether synthesis kettle. After the temperature is raised, an amine ether synthesis reaction is carried out to obtain amine ether.

3. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 2, characterized in that: The crude amine ether is synthesized by using 2-chloroethyl propyl ether and excess DEA under normal pressure and 160° C. to 185° C.

4. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 3, characterized in that: The crude amine ether comprises 20-40% by weight of amine ether, 60-70% by weight of DEA and the remainder of impurities.

5. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 4, characterized in that: The circulating heat-conducting carrier in step (1) is obtained in the following manner: the low-temperature heat-conducting carrier enters the DEA tower top condenser through the heat-conducting carrier circulating pump, the outlet gas from the DEA tower top is condensed and then enters the heat-conducting carrier cooler, and then enters the heat-conducting carrier circulating pump after being cooled by circulating water to obtain the circulating heat-conducting carrier.

6. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 5, characterized in that: The top temperature of the DEA tower in the step (1) is 130-145° C., and the top pressure of the DEA tower in the step (1) is -0.08 to -0.099 MPa.

7. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 2, characterized in that: In the step (2), the circulating heat-conducting carrier is selected from one of heat-conducting oil, water, and a metal salt water solution.

8. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 2, characterized in that: The temperature of the high-temperature DEA in step (2) is ≤125°C.

9. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 8, characterized in that: In the step (2), the temperature of the high-temperature DEA is controlled by controlling the opening of the heat transfer medium regulating valve through the regulating valve interlocking, thereby controlling the amount of circulating heat transfer medium entering the DEA tower top condenser to ensure the temperature of the high-temperature DEA.

10. The process for producing amine ethers by utilizing sensible heat of recovered DEA according to claim 2, characterized in that: In the step (3), the top temperature of the DEA tower is 130-145°C.

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