Production Process of Low-Energy Consumption Epoxy Resin

Abstract

The present invention belongs to the technical field of epoxy resin production, and specifically relates to a production process of low-energy epoxy resin. The steps are: first, bisphenol A is mixed with epichlorohydrin, and bisphenol A is dissolved by high-temperature steam and hot water linkage heating; then the temperature is raised and sodium hydroxide solution is added for pre-reaction; pressure and temperature are controlled, and then sodium hydroxide solution is added for main reaction. After the reaction is completed, epichlorohydrin is recovered by high-temperature steam under different pressure and temperature conditions, and finally the recovery is terminated by low-temperature steam bubbling, the temperature is lowered, and then the temperature is raised and benzyltriethylammonium chloride and sodium hydroxide solution are added for reaction, and the remaining toluene resin is put into a debenzene kettle after two water washings and separations. Finally, debenzene is removed, and toluene recovery and water removal are completed by low-temperature steam bubbling to obtain a product. The production process provided by the present invention makes full use of the steam heat in the production process to obtain hot water for heat reuse, greatly improves energy utilization, is simple to operate and has strong safety.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resin production, and in particular relates to a production process for low-energy consumption epoxy resin. Background Art

[0002] As a high-performance polymer material, epoxy resin has extensive and critical applications in many fields such as aerospace, electronics, and building materials. Its unique chemical structure gives the product good mechanical properties, chemical corrosion resistance, and excellent bonding properties. Therefore, the production process of epoxy resin has always been a research focus in the field of materials science.

[0003] At present, the industrial production process of epoxy resin mainly includes six key processes: dissolution, pre-reaction, main reaction, recovery of epichlorohydrin, refining and debenzening. In the dissolution process, raw materials such as bisphenol A and epichlorohydrin are added to the dissolution kettle. After being treated in a specific way, heating is used to make bisphenol A fully dissolved, laying the foundation for subsequent reactions; the pre-reaction and main reaction processes gradually generate epoxy resin through a series of complex chemical reactions; the refining process aims to remove impurities in the product and improve the purity of the product; and the recovery of epichlorohydrin and debenzening processes are also crucial for resource recycling and product quality improvement.

[0004] However, in the recovery of epichlorohydrin and debenzenization, the existing process has significant defects. The current process converts epichlorohydrin and toluene into high-temperature steam by reducing pressure and raising temperature, and then directly condenses them into low-temperature liquid through a condenser, thereby realizing the recovery of epichlorohydrin and toluene. However, this direct condensation method will cause a large amount of heat to be wasted. At a time when energy is becoming increasingly scarce and energy conservation and emission reduction requirements are becoming more stringent, this energy waste increases production costs. In addition, excessive energy consumption also limits the economic benefits and market competitiveness of enterprises. Therefore, the development of an epoxy resin production process that can effectively reduce heat waste and improve energy utilization efficiency has become a key issue that needs to be urgently solved in the industry.

[0005] The existing technology, such as the production process mentioned in CN114671998A, mainly reduces the energy waste caused by the recovery of epichlorohydrin by reducing the feed of epichlorohydrin, strictly limits the feed ratio of bisphenol A and epichlorohydrin, and ultimately limits the product epoxy equivalent index, and the process applicability is not strong; the production process mentioned in CN118085229A mainly changes the refining process to avoid the generation of a large amount of refining wastewater, and increases the energy consumption of the later wastewater treatment to achieve the purpose of reducing energy consumption, but still cannot solve the energy consumption when recovering epichlorohydrin and toluene. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art, provide a low-energy consumption epoxy resin production process, make full use of the heat of epichlorohydrin and toluene vapor in the production process to obtain hot water for heat reuse, greatly improve energy utilization, and be simple to operate and highly safe.

[0007] The production process of the low-energy consumption epoxy resin of the present invention comprises the following steps:

[0008] (1) Dissolution: Mix and dissolve bisphenol A and epichlorohydrin, and use 160-180°C high-temperature steam and 60-90°C hot water to heat the dissolution system to 40-50°C until bisphenol A is completely dissolved;

[0009] (2) Pre-reaction: Continue to use 160-180℃ high-temperature steam and 60-90℃ hot water to heat the reaction system to 50-60℃, add sodium hydroxide solution, and react for 2-4h to obtain a pre-reaction solution;

[0010] (3) Main reaction: Control the pressure of the reaction system to 15-30 kPa, use 160-180 °C high-temperature steam to raise the temperature of the system to 60-65 °C, add sodium hydroxide solution and react for 2-4 hours to obtain a reaction solution;

[0011] (4) Recovering epichlorohydrin: The pressure of the reaction system is controlled at 15-30 kPa, and at the same time, the system is heated to 100-120°C using 160-180°C high-temperature steam to recover epichlorohydrin under low vacuum. The pressure of the system is then reduced to below 3 kPa, and at the same time, the system is heated to 130-140°C using 160-180°C high-temperature steam to recover epichlorohydrin under high vacuum. Finally, epichlorohydrin is recovered by bubbling with 130-140°C low-temperature steam. After the reaction system is cooled to 80-100°C, the reaction solution is pumped into a refining kettle filled with toluene.

[0012] The epichlorohydrin recovery method comprises the following steps: heating water with epichlorohydrin vapor through a heat exchanger to obtain hot water with a temperature of 60-90° C., condensing the hot water into epichlorohydrin liquid, and pumping the hot water into an epichlorohydrin recovery tank; and directing excess epichlorohydrin vapor to a condenser to condense the hot water into epichlorohydrin liquid, and pumping the hot water into an epichlorohydrin recovery tank; the water with a temperature of 60-90° C. obtained is used in steps (1), (2), and (5);

[0013] (5) Refining: Use high-temperature steam at 160 - 180 °C to raise the temperature of the refining system to 70 - 90 °C, add benzyltriethylammonium chloride and sodium hydroxide solution, react for 1 - 2 h, then add water for the first and second water wash and liquid separation. When performing the first and second water washes, use high-temperature steam at 160 - 180 °C and hot water at 60 - 90 °C for combined heating, maintain the system temperature at 60 - 70 °C, stir for 20 - 40 min, let it stand for 20 - 40 min for liquid separation. During the second water wash, adjust the pH to 6.5 - 7, and pump the remaining toluene resin into the debenzene kettle;

[0014] (6) Debenzing: Use high-temperature steam at 160 - 180 °C to raise the temperature of the refining system to 110 - 130 °C for atmospheric pressure debenzene, then reduce the system pressure to below 3 kPa and at the same time use high-temperature steam at 160 - 180 °C to raise the system temperature to 140 - 160 °C for vacuum debenzene. Finally, use low-temperature steam at 130 - 140 °C for bubbling to complete toluene recovery and water removal to obtain the product resin;

[0015] The debenzene is carried out by removing toluene vapor. The toluene vapor heats water through a heat exchanger to obtain hot water at 60 - 90 °C and condenses into toluene liquid which is pumped into the toluene storage tank. The excess toluene vapor is directly led to a condenser to condense into toluene liquid and pumped into the toluene storage tank. The obtained water at 60 - 90 °C is supplied for use in steps (1), (2), and (5).

[0016] In step (1), the mass ratio of bisphenol A to epichlorohydrin in the feed is 1:1 - 3.

[0017] In step (2), the concentration of the sodium hydroxide solution is 30 - 50 wt%, and the mass ratio of bisphenol A to sodium hydroxide is 20 - 40:1.

[0018] In step (3), the concentration of the sodium hydroxide solution is 30 - 50 wt%, and the mass ratio of bisphenol A to sodium hydroxide is 1:0.3 - 0.4.

[0019] In step (4), the flow rate of the steam bubbling is 20 - 40 Nm 3 / Hr, and the bubbling time is 20 - 30 min.

[0020] In step (5), sodium dihydrogen phosphate is used to adjust the pH.

[0021] In step (5), the mass ratio of bisphenol A to toluene is 1:1.9 - 2.2, benzyltriethylammonium chloride is 0.05 - 0.1% of the mass of bisphenol A, and the mass ratio of bisphenol A to sodium hydroxide is 1:0.01 - 0.02.

[0022] In step (5), the mass ratio of bisphenol A to the pure water for the first water wash is 1:1 - 1.5, and the mass ratio of bisphenol A to the pure water for the second water wash is 1:0.4 - 0.7.

[0023] The flow rate of the steam bubbling in step (6) is 20 - 40 Nm 3 / Hr, and the bubbling time is 30 - 60 min.

[0024] The water removal in step (6) is to use nitrogen to bubble at a flow rate of 20 - 40 Nm 3 / Hr for 30 - 60 min to remove the moisture in the system.

[0025] Specifically, the production process of the low - energy - consumption epoxy resin includes the following steps:

[0026] (1) Dissolution: Add bisphenol A and epichlorohydrin into the dissolution kettle, evacuate and seal with nitrogen to remove oxygen, start the dissolution stirring, use the combined heating of high - temperature steam and hot water to raise the temperature of the dissolution system to 40 - 50 °C, stir until bisphenol A is completely dissolved, and then pump the materials of the dissolution system into the pre - reaction kettle (the mass ratio of bisphenol A to epichlorohydrin in the feed is 1:1 - 3);

[0027] (2) Pre - reaction: Start the stirring of the pre - reaction kettle, evacuate and seal with nitrogen to remove oxygen, use the combined heating of high - temperature steam and hot water to raise the temperature of the pre - reaction system to 50 - 60 °C, then add 30 - 50 wt% sodium hydroxide solution, maintain the temperature stability, react for 2 - 4 h, and then pump the materials into the main reaction kettle (the mass ratio of bisphenol A to sodium hydroxide is 20 - 40:1);

[0028] (3) Main reaction: Start the stirring of the main reaction kettle, evacuate to reduce the system pressure to 15 - 30 kPa while using high - temperature steam to raise the temperature of the system to between 60 - 65 °C, maintain the temperature and pressure constant, and then drop 30 - 50 wt% sodium hydroxide solution into the system within 2 - 4 h to complete the reaction. Finally, displace the system to atmospheric pressure with nitrogen and pump it into the recovered epichlorohydrin kettle. During the reaction process, use a water separator to timely remove the moisture in the system and reflux the epichlorohydrin to the main reaction kettle (the mass ratio of bisphenol A to sodium hydroxide is 1:0.3 - 0.4);

[0029] (4) Recovery of epichlorohydrin: Start the stirring of the recovered epichlorohydrin kettle, evacuate to reduce the system pressure to 15 - 30 kPa while using high - temperature steam to raise the temperature of the system to between 100 - 120 °C for low - vacuum recovery of epichlorohydrin, then reduce the system pressure to below 3 kPa while using high - temperature steam to raise the temperature of the system to 130 - 140 °C for high - vacuum recovery of epichlorohydrin, and finally use low - temperature steam at 20 - 40 Nm 3The steam of epichlorohydrin is bubbled at a flow rate of 20 - 30 min-1 for 20 - 30 min to complete the recovery of epichlorohydrin. After cooling the system to 80 - 100 °C, it is replaced with nitrogen to normal pressure and then pumped into a refining kettle filled with toluene. The epichlorohydrin steam heats water through a heat exchanger to obtain hot water at a temperature of 60 - 90 °C, and is condensed into epichlorohydrin and pumped into the recovered epichlorohydrin storage tank. When the water temperature is heated to 60 - 90 °C, the excess epichlorohydrin steam is directly led to a condenser to be condensed into epichlorohydrin and pumped into the recovered epichlorohydrin storage tank; (where the mass ratio of bisphenol A to toluene is 1:1.9 - 2.2);

[0030] (5) Refining: Start the stirring of the refining kettle, use high-temperature steam to raise the temperature of the refining system to 70 - 90 °C, add benzyltriethylammonium chloride and a 10 - 20 wt% sodium hydroxide solution, keep the temperature for reaction for 1 - 2 h, then add pure water twice for washing and liquid separation. Each time during washing, high-temperature steam and hot water are used in combination for heating, maintaining the system temperature between 60 - 70 °C, stirring for 20 - 40 min, standing for 20 - 40 min and then separating the liquid. During the second washing, sodium dihydrogen phosphate is added to adjust the pH of the system to between 6.5 - 7. Finally, the remaining toluene resin is filtered through a filter press and pumped into a debenzene kettle (the added mass of benzyltriethylammonium chloride is 0.05 - 0.1% of the mass of bisphenol A, the mass ratio of bisphenol A to sodium hydroxide is 1:0.01 - 0.02, the mass ratio of bisphenol A to the mass of pure water in the first washing is 1:1 - 1.5, and the mass ratio of bisphenol A to the mass of pure water in the second washing is 1:0.4 - 0.7);

[0031] (6) Debenzene removal: Start the stirring of the debenzene kettle, use high-temperature steam to raise the temperature of the debenzene system to 110 - 130 °C for atmospheric pressure debenzene removal, then reduce the system pressure to below 3 kPa and at the same time use high-temperature steam to raise the system temperature to 140 - 160 °C for vacuum debenzene removal. Subsequently, use low-temperature steam to bubble at a flow rate of 20 - 40 Nm 3 / Hr for 30 - 60 min to complete the toluene recovery. Finally, use nitrogen to bubble at a flow rate of 20 - 40 Nm 3 / Hr for 30 - 60 min to remove the moisture in the system to obtain the product resin. The toluene steam heats water through another group of heat exchangers to obtain hot water at a temperature of 60 - 90 °C, and is condensed into toluene and pumped into the toluene storage tank. When the water temperature is heated to 60 - 90 °C, the excess toluene steam is directly led to a condenser to be condensed into toluene and pumped into the toluene storage tank.

[0032] The schematic diagram of the energy consumption recovery of the production process of the epoxy resin of the present invention is as shown in Figure 1As shown in the figure, the present invention heats water by using the high-temperature epichlorohydrin steam and high-temperature toluene steam obtained from the epichlorohydrin recovery section and the benzene removal section, and obtains hot water with a temperature ranging from 60 to 90 °C. This hot water meets the heating requirements of the dissolution section, the pre-reaction section, and the refining and water washing section. Therefore, the energy of the epichlorohydrin steam and toluene steam in the epichlorohydrin recovery section and the benzene removal section can be transferred to the dissolution section, the pre-reaction section, and the refining and water washing section for use through hot water as a medium, realizing the recovery and utilization of energy.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The present invention makes full use of the heat of epichlorohydrin and toluene steam in the production process, greatly improving the energy utilization rate.

[0035] (2) The operation of the present invention is simple, easy to transform, and the heat transfer medium is water, with strong safety.

[0036] (3) When heating in the dissolution, pre-reaction, and refining sections, the high-temperature steam and hot water of the present invention can be switched, with strong flexibility for adjustment. Description of the Drawings

[0037] Figure 1 It is a schematic diagram of the energy consumption recovery of the production process of the epoxy resin of the present invention. Detailed Embodiments

[0038] The present invention will be further described below in conjunction with specific embodiments.

[0039] The raw materials and auxiliaries used in the following examples and comparative examples are all commercially available products.

[0040] Example 1

[0041] The production process of the low-energy-consuming epoxy resin includes the following steps:

[0042] (1) Dissolution: 10 t of bisphenol A and 30 t of epichlorohydrin are added to the dissolution kettle, evacuated and sealed with nitrogen to remove oxygen, the dissolution stirring is started, and the dissolution system is heated to 40 °C by the combined use of 160 °C high-temperature steam and 60 °C hot water. After stirring until bisphenol A is completely dissolved, the materials in the dissolution system are pumped into the pre-reaction kettle;

[0043] (2) Pre-reaction: The stirring of the pre-reaction kettle is started, evacuated and sealed with nitrogen to remove oxygen. After the pre-reaction system is heated to 50 °C by the combined use of 160 °C high-temperature steam and 60 °C hot water, 1670 kg of sodium hydroxide solution with a mass concentration of 30% is added, the temperature is maintained stable, and the reaction is carried out for 2 h. Then the materials are pumped into the main reaction kettle;

[0044] (3) Main reaction: Start the stirring of the main reaction kettle, evacuate to reduce the system pressure to 15 kPa, and at the same time use high-temperature steam at 160 °C to heat the system to 60 °C. Keep the temperature and pressure constant, and then drop 10 t of sodium hydroxide solution with a mass concentration of 30% into the system within 4 h to complete the reaction. Finally, displace the system to atmospheric pressure with nitrogen and transfer it to the recovered epichlorohydrin kettle. During the reaction, use a water separator to remove the water in the system in a timely manner, and reflux the epichlorohydrin to the main reaction kettle;

[0045] (4) Recovery of epichlorohydrin: Start the stirring of the recovered epichlorohydrin kettle, evacuate to reduce the system pressure to 15 kPa, and at the same time use high-temperature steam at 160 °C to heat the system to 100 °C for low-vacuum recovery of epichlorohydrin. Then reduce the system pressure to below 3 kPa and use high-temperature steam at 160 °C to heat the system to 130 °C for high-vacuum recovery of epichlorohydrin. Finally, use low-temperature steam at 130 °C to steam-bubble at a flow rate of 20 Nm 3 / Hr for 20 min to complete the recovery of epichlorohydrin. After cooling the system to 80 °C, displace it to atmospheric pressure with nitrogen and transfer it to the refining kettle containing 19 t of toluene. The epichlorohydrin steam heats water through a heat exchanger to obtain hot water at 60 °C and condenses into epichlorohydrin, which is transferred to the recovered epichlorohydrin storage tank. When the water temperature is heated to 60 °C, the excess epichlorohydrin steam is directly led to the condenser to be condensed into epichlorohydrin and transferred to the recovered epichlorohydrin storage tank;

[0046] (5) Refining: Start the stirring of the refining kettle, use high-temperature steam at 160 °C to raise the temperature of the refining system to 70 °C, add 5 kg of benzyltriethylammonium chloride and 1000 kg of sodium hydroxide solution with a mass concentration of 10%, keep the temperature for reaction for 1 h, and then add pure water for washing and liquid separation in two times. Each time during washing, use high-temperature steam at 160 °C and hot water at 60 °C to heat jointly, keep the system temperature at 60 °C, stir for 20 min, stand for 20 min and then separate the liquid. During the second washing, add sodium dihydrogen phosphate to adjust the pH of the system to 6.5. Finally, filter the remaining toluene resin through a filter and transfer it to the debenzene kettle (the mass of pure water for the first washing is 10 t, and the mass of pure water for the second washing is 4 t);

[0047] (6) Debenzene: Start the stirring of the debenzene kettle, use high-temperature steam at 160 °C to raise the temperature of the debenzene system to 110 °C for atmospheric-pressure debenzene, then reduce the system pressure to below 3 kPa and use high-temperature steam at 160 °C to heat the system to 140 °C for vacuum debenzene. Subsequently, use low-temperature steam at 130 °C to steam-bubble at a flow rate of 20 Nm 3 / Hr for 30 min to complete the toluene recovery. Finally, use nitrogen at a flow rate of 20 Nm 3The product resin is obtained by bubbling with a flow rate of / Hr for 30 minutes to remove the moisture in the system. Toluene vapor heats water through another set of heat exchangers to obtain hot water at 60°C and condenses into toluene, which is pumped into the toluene storage tank. When the water temperature is heated to 60°C, the excess toluene vapor is directly led to the condenser to be condensed into toluene and pumped into the toluene storage tank.

[0048] Example 2

[0049] The production process of the low - energy - consumption epoxy resin includes the following steps:

[0050] (1) Dissolution: Add 11.5t of bisphenol A and 28.6t of epichlorohydrin into the dissolution kettle, evacuate and seal with nitrogen to remove oxygen, start the dissolution stirring, and use the combined heating of 165°C high - temperature steam and 68°C hot water to raise the temperature of the dissolution system to 43°C. Stir until bisphenol A is completely dissolved, and then pump the materials in the dissolution system into the pre - reaction kettle;

[0051] (2) Pre - reaction: Start the stirring of the pre - reaction kettle, evacuate and seal with nitrogen to remove oxygen. After using the combined heating of 165°C high - temperature steam and 68°C hot water to raise the temperature of the pre - reaction system to 53°C, add 1300 kg of sodium hydroxide solution with a mass concentration of 35%. Maintain the temperature stability, react for 2.5 h, and then pump the materials into the main reaction kettle;

[0052] (3) Main reaction: Start the stirring of the main reaction kettle, evacuate to reduce the system pressure to 19 kPa, and at the same time use 165°C high - temperature steam to raise the temperature of the system to 62°C. Maintain the temperature and pressure constant, and then drop 10.8t of sodium hydroxide solution with a mass concentration of 35% into the system within 3.5 h to complete the reaction. Finally, replace the system with nitrogen to normal pressure and pump it into the epichlorohydrin recovery kettle. During the reaction, use a water separator to remove the moisture in the system in time, and reflux the epichlorohydrin to the main reaction kettle;

[0053] (4) Recovery of epichlorohydrin: Start the stirring of the epichlorohydrin recovery kettle, evacuate to reduce the system pressure to 19 kPa, and at the same time use 165°C high - temperature steam to raise the temperature of the system to 105°C for low - vacuum recovery of epichlorohydrin. Then reduce the system pressure to below 3 kPa and use 165°C high - temperature steam to raise the temperature of the system to 133°C for high - vacuum recovery of epichlorohydrin. Finally, use 133°C low - temperature steam to bubble with a flow rate of 25 Nm 3 / Hr for 23 minutes to complete the recovery of epichlorohydrin. After cooling the system to 85°C, replace it with nitrogen to normal pressure and pump it into the refining kettle containing 22.6t of toluene. Epichlorohydrin vapor heats water through a heat exchanger to obtain hot water at 68°C and condenses into epichlorohydrin, which is pumped into the epichlorohydrin recovery storage tank. When the water temperature is heated to 68°C, the excess epichlorohydrin vapor is directly led to the condenser to be condensed into epichlorohydrin and pumped into the epichlorohydrin recovery storage tank;

[0054] (5) Refining: Start the agitation of the refining kettle, use high-temperature steam at 165°C to raise the temperature of the refining system to 75°C, add 7 kg of benzyltriethylammonium chloride and 1140 kg of sodium hydroxide solution with a mass concentration of 13%, keep the temperature for reaction for 1.3 h, then add pure water in two batches for water washing and liquid separation. Each time during water washing, use high-temperature steam at 165°C and hot water at 68°C for combined heating, maintain the system temperature at 63°C, stir for 25 min, let it stand for 25 min and then separate the liquid. During the second water washing, add sodium dihydrogen phosphate to adjust the pH of the system to 6.7. Finally, filter the remaining toluene resin through a filter press and transfer it to the debenzene kettle (the mass of pure water for the first water washing is 13.5 t, and the mass of pure water for the second water washing is 5.5 t);

[0055] (6) Debenzylation: Start the agitation of the debenzene kettle, use high-temperature steam at 165°C to raise the temperature of the debenzene system to 115°C for atmospheric pressure debenzylation, then reduce the system pressure to below 3 kPa and at the same time use high-temperature steam at 165°C to raise the system temperature to 145°C for vacuum debenzylation. Subsequently, use low-temperature steam at 133°C to conduct steam bubbling at a flow rate of 25 Nm 3 / Hr for 38 min to complete toluene recovery. Finally, use nitrogen to conduct bubbling at a flow rate of 25 Nm 3 / Hr for 38 min to remove the moisture in the system to obtain the product resin. The toluene vapor heats water through another set of heat exchangers to obtain hot water at 68°C and condenses into toluene, which is transferred to the toluene storage tank. When the water temperature is heated to 68°C, the excess toluene vapor is directly led to the condenser to be condensed into toluene and transferred to the toluene storage tank.

[0056] Example 3

[0057] The production process of the low-energy consumption epoxy resin includes the following steps:

[0058] (1) Dissolution: Add 13.4 t of bisphenol A and 26.7 t of epichlorohydrin to the dissolution kettle, evacuate and seal with nitrogen to remove oxygen. Start the dissolution agitation, use combined heating of high-temperature steam at 170°C and hot water at 75°C to raise the temperature of the dissolution system to 45°C, stir until bisphenol A is completely dissolved, and then transfer the materials in the dissolution system to the pre-reaction kettle;

[0059] (2) Pre-reaction: Start the agitation of the pre-reaction kettle, evacuate and seal with nitrogen to remove oxygen. Use combined heating of high-temperature steam at 170°C and hot water at 75°C to raise the temperature of the pre-reaction system to 55°C, then add 830 kg of sodium hydroxide solution with a mass concentration of 40%, maintain the temperature stability, react for 3 h, and then transfer the materials to the main reaction kettle;

[0060] (3) Main reaction: Start the stirring of the main reactor, evacuate to reduce the system pressure to 23 kPa, and at the same time use high-temperature steam at 170 °C to heat the system to 63 °C. Maintain the temperature and pressure constant, and then drop 11.7 t of sodium hydroxide solution with a mass concentration of 40% into the system within 3 h to complete the reaction. Finally, displace the system to atmospheric pressure with nitrogen and transfer it to the epoxy chloropropane recovery kettle. During the reaction, use a water separator to remove the water in the system in a timely manner, and reflux the epoxy chloropropane to the main reactor;

[0061] (4) Recovery of epoxy chloropropane: Start the stirring of the epoxy chloropropane recovery kettle, evacuate to reduce the system pressure to 23 kPa, and at the same time use high-temperature steam at 170 °C to heat the system to 110 °C for low-vacuum recovery of epoxy chloropropane. Then reduce the system pressure to below 3 kPa and use high-temperature steam at 170 °C to heat the system to 135 °C for high-vacuum recovery of epoxy chloropropane. Finally, use low-temperature steam at 135 °C to steam-bubble at a flow rate of 30 Nm 3 / Hr for 25 min to complete the recovery of epoxy chloropropane. After cooling the system to 90 °C, displace it to atmospheric pressure with nitrogen and transfer it to the refining kettle containing 23.7 t of toluene. The epoxy chloropropane steam heats water through a heat exchanger to obtain hot water at 75 °C and condenses into epoxy chloropropane, which is transferred to the epoxy chloropropane recovery storage tank. When the water temperature is heated to 75 °C, the excess epoxy chloropropane steam is directly led to the condenser to be condensed into epoxy chloropropane and transferred to the epoxy chloropropane recovery storage tank;

[0062] (5) Refining: Start the stirring of the refining kettle, use high-temperature steam at 170 °C to raise the temperature of the refining system to 80 °C, add 10 kg of benzyltriethylammonium chloride and 1330 kg of sodium hydroxide solution with a mass concentration of 15%, keep the temperature for reaction for 1.5 h, and then add pure water in two batches for water washing and liquid separation. Each time during water washing, use high-temperature steam at 170 °C and hot water at 75 °C for combined heating, maintain the system temperature at 65 °C, stir for 30 min, stand for 30 min and then separate the liquid. During the second water washing, add sodium dihydrogen phosphate to adjust the system pH to 6.8. Finally, filter the remaining toluene resin through a filter press and transfer it to the debenzene kettle (the mass of pure water for the first water washing is 16.7 t, and the mass of pure water for the second water washing is 7.4 t);

[0063] (6) Debenzene: Start the stirring of the debenzene kettle, use high-temperature steam at 170 °C to raise the temperature of the debenzene system to 120 °C for atmospheric pressure debenzene, then reduce the system pressure to below 3 kPa and use high-temperature steam at 170 °C to raise the system temperature to 150 °C for vacuum debenzene. Subsequently, use low-temperature steam at 135 °C to steam-bubble at a flow rate of 30 Nm 3 / Hr for 45 min to complete the toluene recovery. Finally, use nitrogen at a flow rate of 30 Nm 3The product resin is obtained by bubbling the flow rate of / Hr for 45 minutes to remove the moisture in the system. Toluene vapor heats water through another set of heat exchangers to obtain hot water at 75°C and condenses into toluene, which is pumped into the toluene storage tank. When the water temperature is heated to 75°C, the excess toluene vapor is directly led to the condenser to be condensed into toluene and pumped into the toluene storage tank.

[0064] Example 4

[0065] The production process of the low - energy - consumption epoxy resin includes the following steps:

[0066] (1) Dissolution: Add 16t of bisphenol A and 24t of epichlorohydrin into the dissolution kettle, evacuate and seal with nitrogen to remove oxygen, start the dissolution stirring, use the combined heating of 175°C high - temperature steam and 83°C hot water to raise the temperature of the dissolution system to 48°C, stir until bisphenol A is completely dissolved, and then pump the materials in the dissolution system into the pre - reaction kettle;

[0067] (2) Pre - reaction: Start the stirring of the pre - reaction kettle, evacuate and seal with nitrogen to remove oxygen, use the combined heating of 175°C high - temperature steam and 83°C hot water to raise the temperature of the pre - reaction system to 58°C, then add 1000 kg of sodium hydroxide solution with a mass concentration of 45%, maintain the temperature stable, react for 3.5 h, and then pump the materials into the main reaction kettle;

[0068] (3) Main reaction: Start the stirring of the main reaction kettle, evacuate to reduce the system pressure to 27 kPa and use 175°C high - temperature steam to raise the temperature of the system to 64°C at the same time, maintain the temperature and pressure constant, and then drop 13.5t of sodium hydroxide solution with a mass concentration of 45% into the system within 2.5 h to complete the reaction. Finally, displace the system to normal pressure with nitrogen and pump it into the epichlorohydrin recovery kettle. During the reaction, use a water separator to remove the moisture in the system in time, and reflux the epichlorohydrin to the main reaction kettle;

[0069] (4)Recovery of epichlorohydrin: Start the stirring of the epichlorohydrin recovery kettle, evacuate to reduce the system pressure to 27 kPa and use 175°C high - temperature steam to raise the temperature of the system to 115°C for low - vacuum recovery of epichlorohydrin, then reduce the system pressure to below 3 kPa and use 175°C high - temperature steam to raise the temperature of the system to 138°C for high - vacuum recovery of epichlorohydrin. Finally, use 138°C low - temperature steam to bubble at a flow rate of 35 Nm 3 / Hr for 28 minutes to complete the recovery of epichlorohydrin. After cooling the system to 95°C, displace it to normal pressure with nitrogen and pump it into the refining kettle containing 34t of toluene. Epichlorohydrin vapor heats water through a heat exchanger to obtain hot water at 83°C and condenses into epichlorohydrin, which is pumped into the epichlorohydrin recovery storage tank. When the water temperature is heated to 83°C, the excess epichlorohydrin vapor is directly led to the condenser to be condensed into epichlorohydrin and pumped into the epichlorohydrin recovery storage tank;

[0070] (5) Refining: Start the refining kettle and stir, use 175℃ high-temperature steam to raise the temperature of the refining system to 85℃, add 14kg benzyltriethylammonium chloride and 1600kg 18% sodium hydroxide solution, keep warm for 1.8h, then add pure water twice for water washing and liquid separation, use 175℃ high-temperature steam and 83℃ hot water to heat each time, maintain the system temperature at 68℃, stir for 35min, let stand for 35min and then separate the liquid, add sodium dihydrogen phosphate for the second water washing to adjust the system pH to 6.9, finally filter the remaining toluene resin through a filter and put it into the debenzene kettle (the mass of pure water for the first water washing is 22t, and the mass of pure water for the second water washing is 10t);

[0071] (6) Debenzening: Start the debenzening kettle and stir. Use 175℃ high-temperature steam to raise the temperature of the debenzening system to 125℃ for atmospheric debenzening. Then reduce the system pressure to below 3kPa and use 175℃ high-temperature steam to raise the system temperature to 155℃ for debenzening under reduced pressure. Then use 138℃ low-temperature steam at 35Nm 3 / Hr flow rate steam bubbling 53min to complete toluene recovery, and finally nitrogen was used at 35Nm 3 / Hr flow rate bubbling for 53min to remove water from the system to obtain product resin. Toluene vapor heats water through another set of heat exchangers to obtain hot water at a temperature of 83°C and condenses into toluene, which is pumped into a toluene storage tank. When the water temperature is heated to 83°C, the excess toluene vapor is directly passed to the condenser to be condensed into toluene, which is pumped into a toluene storage tank.

[0072] Example 5

[0073] The production process of the low-energy consumption epoxy resin comprises the following steps:

[0074] (1) Dissolution: Add 20 tons of bisphenol A and 20 tons of epichlorohydrin into a dissolution kettle, evacuate and seal with nitrogen to remove oxygen, start dissolution stirring, use 180°C high-temperature steam and 90°C hot water to heat the dissolution system to 50°C, stir until bisphenol A is completely dissolved, and then pump the dissolution system materials into the pre-reactor;

[0075] (2) Pre-reaction: Start the pre-reaction kettle for stirring, evacuate and seal with nitrogen to remove oxygen, use 180°C high-temperature steam and 90°C hot water to raise the temperature of the pre-reaction system to 60°C, add 1000kg of 50% sodium hydroxide solution, maintain the temperature stable, react for 4 hours, and then pump the materials into the main reaction kettle;

[0076] (3)Main reaction: Start the stirring of the main reactor, evacuate to reduce the system pressure to 30 kPa, and at the same time use high-temperature steam at 180 °C to heat the system to 65 °C. Maintain the temperature and pressure constant, and then add 16 t of sodium hydroxide solution with a mass concentration of 50% dropwise to the system within 2 h to complete the reaction. Finally, displace the system to atmospheric pressure with nitrogen and transfer it to the recovered epichlorohydrin kettle. During the reaction, use a water separator to remove the water in the system in a timely manner, and reflux the epichlorohydrin to the main reactor;

[0077] (4)Recovery of epichlorohydrin: Start the stirring of the recovered epichlorohydrin kettle, evacuate to reduce the system pressure to 30 kPa, and at the same time use high-temperature steam at 180 °C to heat the system to 120 °C for low-vacuum recovery of epichlorohydrin. Then reduce the system pressure to below 3 kPa and use high-temperature steam at 180 °C to heat the system to 140 °C for high-vacuum recovery of epichlorohydrin. Finally, use low-temperature steam at 140 °C to steam-bubble at a flow rate of 40 Nm 3 / Hr for 30 min to complete the recovery of epichlorohydrin. After cooling the system to 100 °C, displace it to atmospheric pressure with nitrogen and transfer it to the refining kettle containing 44 t of toluene. The epichlorohydrin steam heats water through a heat exchanger to obtain hot water at 90 °C and condenses into epichlorohydrin, which is transferred to the recovered epichlorohydrin storage tank. When the water temperature is heated to 90 °C, the excess epichlorohydrin steam is directly led to the condenser to be condensed into epichlorohydrin and transferred to the recovered epichlorohydrin storage tank;

[0078] (5)Refining: Start the stirring of the refining kettle, use high-temperature steam at 180 °C to raise the temperature of the refining system to 90 °C, add 20 kg of benzyltriethylammonium chloride and 2000 kg of sodium hydroxide solution with a mass concentration of 20%, keep the temperature for reaction for 2 h, and then add pure water for washing and liquid separation in two times. Each time during washing, use high-temperature steam at 180 °C and hot water at 90 °C to heat jointly, maintain the system temperature at 70 °C, stir for 40 min, stand for 40 min and then separate the liquid. During the second washing, add sodium dihydrogen phosphate to adjust the pH of the system to 7. Finally, filter the remaining toluene resin through a filter and transfer it to the debenzene kettle (the mass of pure water for the first washing is 30 t, and the mass of pure water for the second washing is 14 t);

[0079] (6)Debenzene: Start the stirring of the debenzene kettle, use high-temperature steam at 180 °C to raise the temperature of the debenzene system to 130 °C for atmospheric-pressure debenzene, then reduce the system pressure to below 3 kPa and use high-temperature steam at 180 °C to raise the temperature of the system to 160 °C for vacuum debenzene. Subsequently, use low-temperature steam at 140 °C to steam-bubble at a flow rate of 40 Nm 3 / Hr for 60 min to complete the toluene recovery. Finally, use nitrogen at a flow rate of 40 Nm 3The resin product is obtained by bubbling the flow rate of / Hr for 60 min to remove the moisture in the system. The toluene vapor heats the water through another group of heat exchangers to obtain hot water at 90 °C and condenses into toluene, which is pumped into the toluene storage tank. When the water temperature is heated to 90 °C, the excess toluene vapor is directly led to the condenser to be condensed into toluene and pumped into the toluene storage tank.

[0080] Comparative Example 1

[0081] Compared with Example 1, only 160 °C high-temperature steam heating is used in the dissolution section, pre-reaction section, and refining and washing section.

[0082] Comparative Example 2

[0083] Compared with Example 2, only 165 °C high-temperature steam heating is used in the dissolution section, pre-reaction section, and refining and washing section.

[0084] Comparative Example 3

[0085] Compared with Example 3, only 170 °C high-temperature steam heating is used in the dissolution section, pre-reaction section, and refining and washing section.

[0086] Comparative Example 4

[0087] Compared with Example 4, only 175 °C high-temperature steam heating is used in the dissolution section, pre-reaction section, and refining and washing section.

[0088] Comparative Example 5

[0089] Compared with Example 5, only 180 °C high-temperature steam heating is used in the dissolution section, pre-reaction section, and refining and washing section.

[0090] The products obtained from each example and comparative example are tested and the steam unit consumption is calculated. The results are shown in Table 1.

[0091] Table 1 Product indicators and energy consumption results

[0092]

[0093] As can be seen from the above, by comparing Examples 1-5 with Comparative Examples 1-5 respectively, it can be known that when producing epoxy resin using the present invention, the product indexes remain unchanged; the steam unit consumption of Examples 1-5 is significantly lower than that of Comparative Examples 1-5, and the reduction range is about between 4.6% and 6.5%. The experimental data show that the steam heat of the recovered epichlorohydrin and toluene can be effectively utilized by using the method of the present invention, and when the quality of the recovered epichlorohydrin and the recovered toluene is higher and the hot water temperature is higher, the proportion of the reduction in steam unit consumption is greater. The reason is that when more epichlorohydrin and toluene are recovered, more heat will be wasted according to the traditional process operation. When producing resin using the present invention, this part of the heat will be converted into the heat of hot water and reused in the resin production process, and the higher the hot water temperature, the more heat can be conducted, so the proportion of the reduction in steam unit consumption is greater.

Claims

1. A production process for low-energy consumption epoxy resin, characterized in that: The following steps are involved: (1) Dissolution: Mix and dissolve bisphenol A and epichlorohydrin, and use 160-180°C steam and 60-90°C water to heat the dissolution system to 40-50°C until bisphenol A is completely dissolved; (2) Pre-reaction: Continue to use 160-180°C steam and 60-90°C water to heat the reaction system to 50-60°C, add sodium hydroxide solution, and react for 2-4 hours to obtain a pre-reaction solution; (3) Main reaction: Control the pressure of the reaction system to 15-30 kPa, use 160-180 °C steam to raise the temperature of the system to 60-65 °C, add sodium hydroxide solution and react for 2-4 hours to obtain a reaction solution; (4) Recovering epichlorohydrin: The pressure of the reaction system is controlled at 15-30 kPa, and at the same time, 160-180°C steam is used to heat the system to 100-120°C to recover epichlorohydrin, and then the system pressure is reduced to below 3 kPa, and at the same time, 160-180°C steam is used to heat the system to 130-140°C to recover epichlorohydrin in vacuum, and finally, 130-140°C steam is used to bubble to complete the recovery of epichlorohydrin, and after the reaction system is cooled to 80-100°C, the reaction solution is pumped into a refining kettle filled with toluene; The epichlorohydrin recovery method comprises heating water with epichlorohydrin vapor through a heat exchanger to obtain water with a temperature of 60-90° C., condensing the water into epichlorohydrin liquid, and pumping the water into an epichlorohydrin recovery tank; the excess epichlorohydrin vapor is directly passed to a condenser to condense the epichlorohydrin liquid, and pumping the epichlorohydrin recovery tank; the obtained water with a temperature of 60-90° C. is used in steps (1), (2), and (5); (5) Refining: Use 160-180℃ steam to raise the temperature of the refining system to 70-90℃, add benzyltriethylammonium chloride and sodium hydroxide solution, react for 1-2h, then add water for the first and second washing and separation. During the first and second washing, use 160-180℃ steam and 60-90℃ hot water to heat, maintain the system temperature at 60-70℃, stir for 20-40min, stand for 20-40min to separate the liquid, and adjust the pH to 6.5-7 during the second washing, and put the remaining toluene resin into the debenzene kettle; sodium dihydrogen phosphate is used to adjust the pH; benzyltriethylammonium chloride is 0.05-0.1% of the mass of bisphenol A, and the mass ratio of bisphenol A to sodium hydroxide is 1:0.01-0.02; (6) Debenzening: Use 160-180°C steam to raise the temperature of the debenzening system to 110-130°C for atmospheric pressure debenzening, then reduce the system pressure to below 3 kPa, and simultaneously use 160-180°C steam to raise the system temperature to 140-160°C for reduced pressure debenzening, and finally use 130-140°C steam bubbling to complete toluene recovery and water removal to obtain the product resin; The debenzening is carried out in a manner of removing toluene vapor. The toluene vapor is used to heat water through a heat exchanger to obtain hot water with a temperature of 60-90° C., which is condensed into toluene liquid and pumped into a toluene storage tank. Excess toluene vapor is directly passed to a condenser to be condensed into toluene liquid and pumped into a toluene storage tank. The obtained water with a temperature of 60-90° C. is supplied to steps (1), (2) and (5).

2. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The mass ratio of bisphenol A to epichlorohydrin in step (1) is 1:1-3.

3. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step (2) is 30-50wt%, and the mass ratio of bisphenol A to sodium hydroxide is 20-40:

1.

4. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step (3) is 30-50wt%, and the mass ratio of bisphenol A to sodium hydroxide is 1:0.3-0.

4.

5. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The steam bubbling flow rate in step (4) is 20-40 Nm 3 / Hr, bubbling time is 20-30min.

6. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The mass ratio of bisphenol A to the first washing pure water in step (5) is 1:1-1.5, and the mass ratio of bisphenol A to the second washing pure water is 1:0.4-0.

7.

7. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The steam bubbling flow rate in step (6) is 20-40 Nm 3 / Hr, bubbling time is 30-60min.

8. The production process of low energy consumption epoxy resin according to claim 1, characterized in that: The water removal in step (6) is carried out by using nitrogen at 20-40 Nm 3 / Hr flow rate for 30-60min to remove water from the system.

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