A pre-flash energy-saving method for the condensation system of SSBR production equipment

Abstract

The present invention provides a pre-flash energy-saving method for the coagulation system of an SSBR production device. The coagulation system includes a pre-flash tank, a glue preheater, an oil cooler, a vacuum pump, a glue feed pump, and a coagulation kettle. The pre-flash energy-saving method includes the following steps: S10, preheating the glue from the polymerization system to a set temperature through the glue preheater; S20, sending the preheated glue into the pre-flash tank, sucking out the gaseous solvent at the top of the pre-flash tank through the vacuum pump, and sending the glue at the bottom of the pre-flash tank to the coagulation kettle through the glue feed pump; wherein, the gaseous solvent sucked out by the vacuum pump enters the glue preheater for primary heat exchange, and then enters the oil cooler for secondary heat exchange to recover the steam waste heat of the gaseous solvent. By using rapid decompression and vaporization to separate the volatile components before the material enters the main equipment of the coagulation system, the process can significantly reduce the energy consumption of the device because it does not require additional steam consumption in the device.

Description

Technical Field

[0001] The invention relates to the technical field of solution polymer preparation, in particular to a pre-flash energy-saving method for a coagulation system of an SSBR production device. Background Art

[0002] Solution styrene butadiene rubber (SSBR) is a copolymer of styrene and butadiene. It boasts excellent wear resistance, cold resistance, low heat buildup, low shrinkage, and good color. It is widely used in tires, footwear, industrial parts, and other applications. Its production process is generally divided into batch polymerization and continuous polymerization. The latter offers high production efficiency, low energy consumption, and stable product quality. SSBR production equipment includes refining, polymerization, blending, coagulation, and post-processing units. The coagulation stage plays a crucial role in improving product purity and quality.

[0003] However, existing coagulation processes present several challenges. First, fluctuations in the polymerization reactor operating conditions during the coagulation process can lead to excessive moisture in the gas phase, producing solvent-containing wastewater, which impacts downstream wastewater treatment and increases costs. Second, steam heating results in high steam usage and high operating costs. Finally, excessive agitation intensity can cause the colloidal particles to break up, producing a large number of fine colloidal particles, increasing the loss rate and the risk of system clogging. These issues limit production efficiency and lead to increased energy consumption and operating costs.

[0004] Although some technologies have been improved, such as improving oil-water separation efficiency and improving steam injection control, the effects are limited and the main problems in the condensation process have not been effectively solved. In addition, some improvement plans consume a lot of heat and the energy-saving effect is not obvious. Summary of the Invention

[0005] This invention provides an energy-saving pre-flash method for the coagulation system of an SSBR production unit. This method uses rapid decompression and vaporization to separate volatile components before the material enters the main coagulation unit, thereby reducing the load on subsequent processes or optimizing operating conditions. Because this process does not require additional steam consumption within the unit, it significantly reduces energy consumption and wastewater discharge.

[0006] To achieve the above-mentioned purpose, the present invention provides a pre-flash energy-saving method for a condensation system of an SSBR production device, wherein the condensation system includes a pre-flash tank, a glue liquid preheater, an oil cooler, a vacuum pump, a glue liquid feed pump, and a condensation kettle; the pre-flash energy-saving method includes the following steps: S10, preheating the glue liquid from the polymerization system to a set temperature through a glue liquid preheater; S20, sending the preheated glue liquid into the pre-flash tank, sucking out the gaseous solvent at the top of the pre-flash tank through a vacuum pump, and sending the glue liquid at the bottom of the pre-flash tank to the condensation kettle through a glue liquid feed pump; wherein the gaseous solvent sucked out by the vacuum pump enters the glue liquid preheater for primary heat exchange, and then enters the oil cooler for secondary heat exchange to recover the steam waste heat of the gaseous solvent.

[0007] Furthermore, in S20, the gaseous solvent at the top of the pre-flash tank is sucked out by a vacuum pump, so that the pressure in the pre-flash tank is maintained at a slightly negative pressure; wherein the pressure range of the slightly negative pressure is -0.08 MPa to 0.01 MPa.

[0008] Furthermore, in S20, the glue at the bottom of the pre-flash tank is pumped to a static mixer through a glue feed pump, mixed with a dispersant, and then sent to a coagulation kettle; wherein the dispersant includes sodium polycarboxylate, sodium oleate or sodium stearate.

[0009] Furthermore, after the gaseous phase solvent undergoes secondary heat exchange in the oil cooler, the condensed liquid phase solvent flows into the solvent buffer tank, and the non-condensable gas in the oil cooler is introduced into the exhaust gas collection system.

[0010] Furthermore, the flashing amount of the glue solution at the bottom of the pre-flash tank is controlled at 65%-80%.

[0011] Furthermore, the set temperature of the glue solution preheated in the glue solution preheater is 80°C-100°C.

[0012] Furthermore, the residence time of the glue solution in the pre-flash tank is ≥120 seconds.

[0013] Furthermore, the condensation system is provided with a temperature-pressure cascade control system, which is used to synchronously adjust the outlet temperature of the glue preheater when adjusting the pressure of the pre-flash tank; wherein, the temperature-pressure cascade control system includes a main loop and a sub-loop, the main loop is used to control the pressure of the pre-flash tank, and the sub-loop is used to control the outlet temperature of the glue preheater.

[0014] Furthermore, the preheater includes a first temperature transmitter and a gas phase solvent outlet regulating valve; the pre-flash tank includes a pressure transmitter, a pressure regulating valve, a flow meter, a feed regulating valve, and a liquid level meter; and the oil cooler includes a second temperature transmitter and a return water flow regulating valve.

[0015] Furthermore, a logical interlock control is formed between the first temperature transmitter and the gas phase solvent outlet regulating valve; a logical interlock control is formed between the pressure transmitter and the pressure regulating valve and the vacuum pump; a logical interlock control is formed between the flow meter and the feed regulating valve and the vacuum pump; a logical interlock control is formed between the liquid level meter and the glue feed pump; and a logical interlock control is formed between the second temperature transmitter and the return water flow regulating valve.

[0016] After adopting the technical solution of the present invention, the following technical effects can be achieved:

[0017] (1) Improve the efficiency of solvent removal and reduce the load of subsequent processes: This process can efficiently separate 65%-80% of the solvent in the glue solution through rapid decompression and vaporization, significantly reducing the steam stripping load of the subsequent condensation reactor. It is expected to directly reduce the steam consumption by 30%-50%, directly reducing energy consumption costs. At the same time, the viscosity of the glue solution after pre-flash evaporation is controllable, reducing the excessive mass transfer resistance caused by excessive viscosity inside the condensation reactor, and further shortening the reaction time. Compared with traditional steam stripping, this process uses vacuum pump-assisted flash evaporation to reduce heat energy consumption by 30%-50%, and frequency conversion control and flash gas phase solvent waste heat recovery further reduce power consumption by 10%-20%. Using slightly negative pressure operating conditions, the flash evaporation speed can be increased by 20%-40%, and the solvent residue is lower.

[0018] (2) Energy saving and consumption reduction and resource recycling optimization: The solvent vapor separated after pre-flash evaporation can be efficiently recovered after condensation and directly used in the polymerization process after refinement, forming a virtuous cycle. At the same time, it can significantly reduce the COD content in the wastewater and reduce the load of the back-end sewage treatment unit.

[0019] (3) Improve product quality and process stability: The pre-flash process can prevent thermal degradation of rubber by precisely controlling temperature, pressure, and residence time, ensuring the stability of key indicators such as the product's Mooney viscosity and molecular weight distribution. It also rapidly removes solvents and oligomers, reducing the risk of self-polymerization of residual monomers in the rubber phase and improving product purity. It is expected that the ash content of SSBR can be reduced to below 0.05%, meeting the requirements of high-end, high-performance tires.

[0020] (4) Enhanced production safety and equipment life: The pre-flash process significantly reduces the explosion risk of the coagulation unit by removing most of the solvent at the front end. The operating conditions of the pre-flash tank are milder than those of the coagulation kettle, which reduces the rate of equipment coking and corrosion, extends the service life of the equipment, and reduces maintenance costs.

[0021] (5) Promote green manufacturing and low-carbon transformation: The pre-flash process directly reduces the carbon emission intensity of the device by reducing steam consumption and solvent emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 A structural diagram of a first embodiment of the present invention.

[0024] Description of reference numerals:

[0025] 1-Glue liquid preheater; 2-Oil cooler; 3-Oil-gas condenser; 4-Static mixer; 5-Pre-flash tank; 6-First kettle; 7-Middle kettle; 8-Last kettle; 9-Oil-water stratification tank; 10-Solvent buffer tank; 11-Vacuum pump; 12-Glue liquid feed pump; 13-First kettle colloid water pump; 14-Middle kettle colloid water pump; 15-Last kettle colloid water pump; 16-Stratification water pump; 17-Solvent delivery pump; 18-Steam jet pump; 19-Reactant feed port; 20-Hot water feed port; 21-Dispersant feed port; 22-Glue liquid discharge port; 23-Wet solvent discharge port. DETAILED DESCRIPTION

[0026] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0027] Solution styrene butadiene rubber (SSBR) is a rubber elastomer produced through the copolymerization of styrene and butadiene. It exhibits properties such as wear resistance, cold resistance, low heat generation, low shrinkage, good color, low ash content, high purity, and rapid vulcanization. Its polymerization processes are primarily batch and continuous. The continuous process offers high production efficiency, low energy consumption, and consistent product quality. SSBR is widely used in the tire industry, particularly in high-performance tires such as green and non-skid tires. It also has numerous applications in footwear, industrial parts, clothing, plastic modification, adhesives, and other fields. Due to its excellent overall performance, SSBR has become a key new synthetic rubber type being researched, developed, and produced worldwide.

[0028] The SSBR production unit primarily consists of a tank farm, a refining unit (including butadiene, styrene, and solvent refining), an additive preparation and polymerization unit, a blending unit, a coagulation unit, a post-processing unit, and auxiliary facilities. Refined butadiene, styrene monomer, solvent oil, and initiator are fed into a polymerization kettle in a specific ratio for polymerization. The resulting rubber solution is pumped to the blending tank for blending before being fed into a coagulation kettle for coagulation. The coagulation process separates the solvent by evaporating it. The rubber solution then enters post-processing for dehydration and drying. Finally, it is metered, packaged, and stored as a finished product.

[0029] The coagulation stage is a key step in the production of solution-polymerized styrene-butadiene rubber (SBR). The coagulation process typically occurs in a series of three coagulation reactors. The latex produced in the polymerization unit is mixed with a dispersant in appropriate proportions and then enters the first coagulation reactor. Under stirring and steam, the latex, hot water, and steam are thoroughly mixed in the first reactor, and the solvent, butadiene, and some water are removed as vapor. The colloidal water at the bottom of the first reactor is pumped into the middle and final coagulation reactors, where steam is introduced to heat the colloidal water and further recover the solvent from the latex. The vaporous solvent at the top of the coagulation reactor is collected through a pipeline and condensed in an oil-gas condenser. It then flows into an oil-water separator tank for solvent recovery. The recovered crude solvent is processed in a refining unit and recycled. The colloidal water in the final reactor is then sent to a post-processing unit for further dehydration and drying to ensure that the water content of the colloidal particles is fully removed, resulting in a dry SBR product.

[0030] The primary function of the coagulation unit is to separate and purify impurities such as unreacted raw materials and oligomers, thereby improving product purity and quality. Operating conditions within the coagulation reactor (such as temperature and pressure) directly affect the crystallization and hardness of the rubber particles, while the type and dosage of the dispersant influence the dispersion and stability of the rubber particles. Therefore, the coagulation unit plays a crucial role in the production of solution-polymerized styrene-butadiene rubber (SBR), influencing not only the purity and quality of the product but also its physical properties, processing characteristics, and application performance. Therefore, in the production process of SBR, the design and operation of the coagulation unit must be given high priority to ensure that product quality and performance meet requirements.

[0031] However, the existing coagulation process has the following major defects: (1) During the coagulation process, due to fluctuations in the operating conditions of the polymerization reactor, it is easy to cause excessive water in the gas phase of the coagulation reactor, thereby generating a large amount of wastewater containing solvents. The high oil content of these wastewaters not only seriously affects the water quality and load of the downstream sewage treatment unit, increasing the treatment cost, but also leads to excessive discharge of solvents, resulting in waste of raw materials, thereby increasing production costs. (2) The coagulation unit removes the solvent, unreacted raw materials and oligomers from the glue solution by introducing steam into the coagulation reactor for heating, but the high steam consumption leads to high operating costs. (3) During the coagulation process, the temperature cannot be accurately controlled, which easily leads to overheating of the glue solution, thereby causing thermal degradation of the rubber molecular chain and affecting product quality. (4) Due to the low viscosity of the glue solution, excessive stirring intensity or excessive speed will generate excessive shear force, resulting in the breakage of the glue particles. This not only affects the product quality, but may also cause system blockage, leading to unplanned shutdowns and frequent maintenance.

[0032] The efficiency of the coagulation process directly impacts the production capacity and profitability of a solution-polymerized styrene-butadiene rubber (SBR) production line. Due to the aforementioned issues, production efficiency is often limited. Furthermore, maintaining coagulation efficiency and addressing issues such as wastewater and wet rubber spots increase overall energy consumption and operating costs, leading to lower product profit margins.

[0033] Furthermore, there are the following deficiencies in the early process technology improvements: (1) To address the problem of solvent entrainment in the wastewater of the condensation unit, the oil-water separation efficiency was improved by improving the equipment (such as the oil-water separation tank) and reducing the proportion of the oil phase entering the water phase. However, due to the incomplete separation effect, this measure has limited effect on reducing the oil content in the wastewater. (2) To address the problem of excessive steam consumption in the condensation unit, the steam injection amount was adjusted by improving the steam injection pump and adopting advanced control technology to reduce energy consumption. However, the procurement cost of this equipment and system is high, the operation flexibility is small, and the control reaction has a lag. If the process conditions fluctuate frequently, the treatment effect of the condensation section cannot be guaranteed, and a large amount of waste rubber may be generated, increasing the proportion of defective products. (3) In order to maintain the treatment effect and reduce problems such as wet spot rubber and broken rubber, it is often necessary to increase the amount of dispersant added. This not only increases production costs, but also excessive dispersant will increase the labor intensity of workers. (4) Patent CN104072643A proposes a solution of flash evaporation at normal pressure after heating, but its flash evaporation effect is poor, and the removal efficiency is only 20-60wt%. Furthermore, this solution requires heating the feed glue solution to 130°C using an external heat source, consuming significant amounts of heat and resulting in limited energy savings. Furthermore, the flash tank has a steam line at the bottom, relying on steam-assisted stripping, which reduces steam usage to a limited extent.

[0034] Through these analyses, it can be seen that although the existing technological improvements have alleviated the problem to a certain extent, there are still defects such as low efficiency, high energy consumption and high cost, and further optimization and improvement are needed.

[0035] An embodiment of the present invention provides a pre-flash energy-saving method for a condensation system of an SSBR production device, wherein the condensation system includes a pre-flash tank, a glue liquid preheater, an oil cooler, a vacuum pump, a glue liquid feed pump, and a condensation kettle; the pre-flash energy-saving method includes the following steps: S10, preheating the glue liquid from the polymerization system to a set temperature through a glue liquid preheater; S20, sending the preheated glue liquid into the pre-flash tank, sucking out the gaseous solvent at the top of the pre-flash tank through a vacuum pump, and sending the glue liquid at the bottom of the pre-flash tank to the condensation kettle through a glue liquid feed pump; wherein the gaseous solvent sucked out by the vacuum pump enters the glue liquid preheater for primary heat exchange, and then enters the oil cooler for secondary heat exchange to recover the steam waste heat of the gaseous solvent.

[0036] The present invention relates to a pre-flash energy-saving method for the coagulation system of an SSBR (styrene-butadiene rubber) production facility. By utilizing waste heat recovery technology, this method reduces energy consumption and improves energy efficiency during the production process. Specifically, a preheater heats the latex solution to a predetermined temperature, reducing the energy required in subsequent steps. A pre-flash tank separates the solvent and colloid from the latex solution through partial evaporation, facilitating subsequent processing. A vacuum pump extracts the vaporous solvent from the top of the pre-flash tank and directs it for recovery. The vaporous solvent's residual heat is recovered and used to preheat the latex solution. This method not only reduces waste heat emissions but also utilizes the recovered heat to reduce external energy consumption. In the latex solution preheater, the vaporous solvent exchanges heat with the incoming cold latex solution, raising the latex solution temperature. Furthermore, the preheated vaporous solvent enters the oil cooler for further heat exchange, resulting in more efficient heat recovery and improving the overall thermal energy efficiency of the system.

[0037] Specifically, the process flow of the glue pre-flash evaporation process of the condensation system disclosed in the present invention is described as follows: the glue from the polymerization system is first heated to a set temperature through a glue preheater. The heat source of the glue preheater is the gaseous solvent after flash evaporation (≥90°C), which reduces the viscosity and promotes flash evaporation. The control range of the preheating temperature is 80°C-100°C. Since the solution polymerization of styrene-butadiene rubber (SSBR) process adopts solution polymerization, the solution is selected as cyclohexane and n-hexane. The pressure needs to be maintained during preheating to improve the flash evaporation efficiency. Compared with the technical means of using an external steam heat source for heating in the prior art, the present invention uses the gaseous steam after flash evaporation for preheating to increase energy utilization, effectively reduce the amount of circulating water and preheating steam in the rear-end oil cooler, and thus reduce the energy consumption of the overall device.

[0038] The preheated glue liquid enters the pre-flash tank through the feed regulating valve. A vacuum pump is used in the pre-flash tank to extract the gas phase in the tank in time, so that the pressure in the tank is maintained at a slightly negative pressure to enhance the flash evaporation effect. The operating pressure control range of the pre-flash tank is -0.08MPa to 0.01MPa. Compared with the atmospheric pressure flash evaporation process in the prior art, the pre-flash tank in this process is a high-temperature negative pressure environment, and the flash evaporation effect and flash evaporation efficiency of the solvent will be greatly enhanced. At the same time, no steam pipeline is introduced at the bottom of the flash tank of this process, reducing the risk of steam leakage and increasing the purity of the flash solvent. The present invention utilizes the decompression effect of the material when passing through the regulating valve, and adds a pre-flash tank after the regulating valve to pre-flash the material. By optimizing the solvent removal process, the production efficiency, energy utilization and product quality are significantly improved, which has far-reaching significance for the economy and sustainability of chemical production.

[0039] Furthermore, the core principle of vacuum pump-assisted flash evaporation is to reduce the pressure in the flash tank, allowing the solvent to evaporate quickly at a lower temperature, reducing dependence on external heat sources. The vacuum pump is the main energy-consuming equipment. The vacuum pump selected for this process is a three-stage variable frequency Roots vacuum pump. Equipped with a frequency conversion function, it can reduce the ineffective operation time of the vacuum pump and reduce power consumption. At the same time, according to the pressure transmitter and pressure regulating valve of the pre-flash tank, the vacuum degree in the tank can be adjusted in real time to avoid energy waste caused by excessive vacuuming. At the same time, it is logically interlocked with the feed regulating valve and the feed flow meter, and the vacuum degree is used to optimize the opening of the feed regulating valve in real time to control the feed flow rate of the material, reduce flow resistance, and reduce the load on the vacuum pump.

[0040] The solvent and low-boiling-point volatile substances such as oligomers in the glue liquid are quickly vaporized and separated from the glue liquid. The gaseous solvent at the top of the pre-flash tank is sucked out by a vacuum pump and enters the glue liquid preheater for a primary heat exchange with the fed glue liquid. The gaseous solvent after heat exchange then enters the oil cooler for a secondary heat exchange. The condensed crude solvent condensate flows by gravity into the solvent buffer tank in the device and is then sent to the refining unit for recycling. Compared with the prior art in which the flash gas condensate enters the oil-water stratification tank, since there is no steam pipeline at the bottom of the flash tank in this process and the number of condensation kettles is three, the subsequent solvent removal capacity is guaranteed. The flash gas condensate in this process directly enters the solvent buffer tank, which saves the energy consumption of the solvent delivery pump and reduces the generation of sewage. In addition, the non-condensable gas in the oil cooler is incorporated into the tail gas collection system and sent to the RTO of the device for treatment.

[0041] By recovering the residual heat of the solvent vapor after flash evaporation, the integrated temperature, pressure, and flow sensors collect all data and connect it to an external large-scale model. Through deep learning using AI, the optimal operating point is determined, achieving dynamic energy conservation. Feedforward-feedback control is also introduced to proactively respond to feed fluctuations, reducing solvent loss and increased energy consumption caused by pressure fluctuations. As a result, the preparation process of the present invention is more sophisticated and intelligent.

[0042] The rubber liquid at the bottom of the pre-flash tank is pumped to a static mixer by the rubber liquid feed pump at the bottom of the tank. After being thoroughly mixed with the dispersant, it enters the subsequent coagulation reactor, where residual solvent is further removed through steam stripping. To avoid excessive rubber liquid viscosity, which can cause pipeline blockage and uneven dispersant mixing, the solvent flash volume of the rubber liquid at the bottom of the pre-flash tank is controlled at 65%-80%. This ensures solvent removal efficiency and reduces subsequent stripping steam usage, while also ensuring that the rubber liquid does not become too viscous and difficult to transport. Preferably, an anti-scaling agent can be regularly injected into the pre-flash tank to prevent residual rubber particles from coking.

[0043] In some embodiments of the present application, in S20, the gaseous solvent at the top of the pre-flash tank is sucked out by a vacuum pump, so that the pressure in the pre-flash tank is maintained at a slightly negative pressure; wherein the pressure range of the slightly negative pressure is -0.08 MPa to 0.01 MPa.

[0044] By using a vacuum pump to remove the vaporized solvent from the top of the pre-flash tank, the pressure within the tank can be effectively reduced, which can effectively improve the flash evaporation efficiency and promote the volatilization or separation of the solvent in the glue solution. Controlling micro-negative pressure is crucial to the glue solution processing process, as it can avoid excessive evaporation or unnecessary material loss due to too low pressure, while also ensuring that the glue solution can maintain its stability under mild conditions. The micro-negative pressure range of -0.08MPa to 0.01MPa provides a precisely controlled environment that can effectively promote the volatilization of the glue solution without causing excessive damage to its components.

[0045] In some embodiments of the present application, in S20, the glue at the bottom of the pre-flash tank is pumped to a static mixer through a glue feed pump, mixed with a dispersant, and then sent to a coagulation kettle; wherein the dispersant includes sodium polycarboxylate, sodium oleate or sodium stearate.

[0046] The present invention further optimizes the mixing step of the glue and dispersant during the glue processing process. Specifically, in step S20, the glue at the bottom of the pre-flash tank is pumped to a static mixer via a glue feed pump, where it is mixed with the dispersant. The mixed glue is then sent to a coagulation reactor for subsequent processing. Sodium polycarboxylate can provide a good dispersion effect and reduce heterogeneity in the glue; fatty acid salt dispersants such as sodium oleate and sodium stearate can also effectively prevent particle aggregation in the glue, helping to improve the fluidity and stability of the glue.

[0047] Furthermore, the use of a static mixer in combination with a dispersant can not only improve dispersion efficiency, but also reduce energy consumption. Compared with traditional mechanical mixing methods, a static mixer is easy to operate, has low energy consumption, and is more economical and environmentally friendly.

[0048] In some embodiments of the present application, after the gaseous phase solvent undergoes secondary heat exchange in the oil cooler, the condensed liquid phase solvent flows into the solvent buffer tank, and the non-condensable gas in the oil cooler is introduced into the exhaust gas collection system.

[0049] The present invention relates to a process for recovering and condensing a vapor-phase solvent. The vapor-phase solvent undergoes a secondary heat exchange process while passing through an oil cooler, lowering its temperature through heat exchange between the oil and gas. During this process, the oil passing through the oil cooler absorbs heat from the vapor-phase solvent, cooling it and promoting its condensation into a liquid-phase solvent. The liquid solvent is then efficiently collected and stored in a solvent buffer tank.

[0050] In the oil cooler, some gases may not be fully condensed, known as non-condensable gases. These gases are directed to the tail gas collection system for further processing. The tail gas collection system is equipped with a purification device to treat these gases before discharge, ensuring compliance with environmental protection requirements. In this process, the flash gas condensate is directly fed into the solvent buffer tank, saving energy consumption of the solvent delivery pump and reducing wastewater generation.

[0051] In some embodiments of the present application, the flash evaporation amount of the glue solution at the bottom of the pre-flash tank is controlled at 65%-80%.

[0052] The pre-flash tank is used in the pretreatment process of the glue liquid. The glue liquid is flashed at a certain pressure and temperature. That is, through changes in temperature or pressure, some of the volatile components in the glue liquid are vaporized into the gas phase. This process can remove unnecessary components or impurities in the glue liquid, while improving the quality and performance of the glue liquid. To avoid excessive glue viscosity, which can cause pipeline blockage and uneven dispersant mixing, the glue liquid solvent flash volume at the bottom of the pre-flash tank is controlled at 65%-80%. This not only ensures solvent removal efficiency and reduces the subsequent stripping steam consumption, but also ensures that the glue liquid does not become too viscous and difficult to transport.

[0053] In some embodiments of the present application, the set temperature for preheating the glue in the glue preheater is 80°C-100°C.

[0054] Heating the adhesive to a set temperature improves its fluidity and reduces its viscosity, ensuring greater stability and efficiency during subsequent processing and reactions. Preheating the adhesive reduces its viscosity, facilitating smoother processing. Preheating also ensures that the adhesive's components are evenly distributed at the desired temperature, avoiding uneven or unstable processing due to temperature variations.

[0055] In some embodiments of the present application, the residence time of the glue solution in the pre-flash tank is ≥120 seconds.

[0056] By adjusting the residence time of the glue solution in the pre-flash tank, the glue solution has sufficient time to undergo a thorough flash reaction. During this process, the components in the glue solution can be fully separated and volatilized, thereby improving the effectiveness of the flash process. Compared with atmospheric pressure flash evaporation, the reduced pressure flash evaporation process of the present invention has higher flash evaporation efficiency. Therefore, the residence time of the glue solution in the pre-flash tank is short, the separation efficiency is high, and this also avoids the problems of rubber coking and kettle wall sticking caused by long residence time.

[0057] In some embodiments of the present application, the condensation system is provided with a temperature-pressure cascade control system for synchronously adjusting the outlet temperature of the glue preheater when adjusting the pressure of the pre-flash tank; wherein the temperature-pressure cascade control system includes a main loop and a sub-loop, the main loop is used to control the pressure of the pre-flash tank, and the sub-loop is used to control the outlet temperature of the glue preheater.

[0058] In the temperature-pressure cascade control system, the primary circuit controls the pre-flash tank pressure, while the secondary circuit primarily controls the outlet temperature of the rubber preheater. Through the synergistic effect between the primary and secondary circuits, while the primary circuit adjusts the pre-flash tank pressure, the secondary circuit simultaneously adjusts the preheater temperature. This ensures a coordinated relationship between temperature and pressure during the rubber preheating process, thus avoiding problems with rubber delivery caused by excessive rubber concentration.

[0059] In some embodiments of the present application, the preheater includes a first temperature transmitter and a gas phase solvent outlet regulating valve; the pre-flash tank includes a pressure transmitter, a pressure regulating valve, a flow meter, a feed regulating valve, and a liquid level meter; and the oil cooler includes a second temperature transmitter and a return water flow regulating valve.

[0060] The first temperature transmitter monitors the temperature in the preheater and transmits this data in real time to adjust the glue solution's temperature, ensuring it reaches the desired temperature during preheating. The vapor solvent outlet regulating valve controls the flow of the vapor solvent, adjusting its outflow rate and thereby controlling the mixing ratio and treatment effect of the vapor solvent and glue solution, optimizing the glue solution's preheating process.

[0061] The pressure transmitter monitors pressure changes in the pre-flash tank and provides real-time feedback to the control system to ensure that the tank pressure remains stable within the desired range. The pressure regulating valve automatically adjusts the pre-flash tank pressure based on the pressure transmitter data, ensuring it operates at the optimal operating pressure. The flow meter measures the flow of the adhesive entering the pre-flash tank, assisting the control system in monitoring and regulating the flow rate. The feed regulating valve adjusts the amount of adhesive entering the pre-flash tank based on the flow meter data, ensuring an appropriate flow rate to prevent excessive or insufficient input that could affect the processing effect. The level gauge monitors the liquid level in the pre-flash tank, ensuring it remains within a reasonable range and preventing system imbalances caused by excessively high or low levels.

[0062] The second temperature transmitter measures the oil cooler's temperature and transmits this data in real time to control and adjust the cooler's cooling efficiency. The return water flow control valve adjusts the return water flow based on the temperature sensor's data to ensure optimal cooling, preventing system overheating that could reduce efficiency or damage the system.

[0063] In some embodiments of the present application, a logical interlock control is formed between the first temperature transmitter and the gas phase solvent outlet regulating valve; a logical interlock control is formed between the pressure transmitter and the pressure regulating valve and the vacuum pump; a logical interlock control is formed between the flow meter and the feed regulating valve and the vacuum pump; a logical interlock control is formed between the liquid level meter and the glue feed pump; and a logical interlock control is formed between the second temperature transmitter and the return water flow regulating valve.

[0064] This invention further optimizes automated control and collaborative work within the glue processing process by establishing logical interlocking controls between key components. Specifically, a logical interlocking mechanism coordinates multiple sensors with control valves, pumps, and other equipment within the system, ensuring that each link can make synchronized adjustments based on real-time data.

[0065] Figure 1 A process flow chart of a pre-flash energy-saving method for a condensation system of an SSBR production device provided in an embodiment of the present invention.

[0066] The condensation system includes a pre-flash tank 5, a glue liquid preheater 1, an oil cooler 2, a vacuum pump 11, a glue liquid feed pump 12, and a condensation kettle; the pre-flash energy-saving method includes the following steps: S10, preheating the glue liquid from the polymerization system to a set temperature through the glue liquid preheater 1; S20, sending the preheated glue liquid into the pre-flash tank 5, and sucking out the gaseous solvent at the top of the pre-flash tank 5 through the vacuum pump 11, so that the pressure in the pre-flash tank 5 is maintained at a slightly negative pressure; the glue liquid at the bottom of the pre-flash tank 5 is sent to the static mixer 4 through the glue liquid feed pump 12, and mixed with the dispersant, and then sent to the condensation kettle.

[0067] The vaporous solvent, drawn by vacuum pump 11, enters glue preheater 1 for primary heat exchange, and then enters oil cooler 2 for secondary heat exchange to recover the vaporous solvent's residual heat. After secondary heat exchange in oil cooler 2, the condensed liquid solvent flows into solvent buffer tank 10, and the non-condensable gases in oil cooler 2 are directed to the exhaust gas collection system.

[0068] The coagulation reactor consists of a first reactor 6, a middle reactor 7, and a final reactor 8. Heavy component A is extracted from the bottom of the first reactor 6 via a first reactor colloidal water pump 13 and delivered to the middle reactor 7. Heavy component B is extracted from the bottom of the middle reactor 7 via a middle reactor colloidal water pump 14 and delivered to the final reactor 8. The glue liquid is extracted from the bottom of the final reactor 8 via a final reactor colloidal water pump 15 and delivered to the glue liquid discharge port 22. Light component A is extracted from the top of the first reactor 6 and, after heat exchange in the oil-gas condenser 3, is delivered to the oil-water separator 9. The separated water in the oil-water separator 9 is delivered to the hot water feed port 20 via a separator water pump 16. The separated oil is then delivered to the solvent buffer tank 10 to produce the wet solvent, which is then delivered to the wet solvent discharge port 23 via a solvent delivery pump 17. Light component B is extracted from the top of the middle reactor 7 and delivered to the first reactor 6. Light component C is extracted from the top of the final reactor 8 and pumped by a steam jet pump 18 before being delivered to the first reactor 6. The reactant feed port 19 is connected to the glue solution preheater 1 , the hot water feed port 20 is connected to the first kettle 6 , and the dispersant feed port 21 is connected to the static mixer 4 .

[0069] The process parameters of the pre-flash energy-saving method are as follows:

[0070] (1) Temperature control: The temperature of the rubber solution must be controlled to avoid thermal degradation of the rubber due to excessive temperature; control range: 80℃-100℃; control method: by integrating temperature, pressure, and flow sensors, all data are collected and connected to an external large model. After the external large model conducts deep learning on the data set, it will provide the optimal operating point.

[0071] (2) Pressure control: The lower the pressure of the pre-flash tank, the higher the solvent vaporization rate. It is necessary to avoid excessive pressure reduction, which may cause the rubber liquid to foam or carry rubber particles. Control range: -0.08MPa to 0.01MPa. Control method: By connecting a vacuum pump to control the pressure in the tank to maintain a slight negative pressure, the pressure transmitter and pressure regulating valve of the pre-flash tank can be used to adjust the vacuum degree in the tank in real time.

[0072] (3) Feed flow rate and residence time: Too low a flow rate affects production capacity, while too high a flow rate affects separation efficiency. Control method: Establish a control loop through the mass flow rate of the feed line and the feed regulating valve to stabilize the feed flow rate. Residence time: Ensure that the residence time of the glue solution in the pre-flash tank is ≥120 seconds.

[0073] (4) Liquid level control: If the liquid level is too high, the gas phase space will be insufficient and the flash evaporation effect will be affected. If the liquid level is too low, the pump will be emptied. Control range: 40±5%. Control method: The liquid level is controlled by interlocking the glue feed pump at the bottom of the tank with a radar level gauge.

[0074] (5) Rubber liquid characteristics: When the solvent content in the feed rubber liquid fluctuates, the pressure and temperature need to be adjusted synchronously to avoid the rubber viscosity being too high and affecting the rubber liquid delivery.

[0075] The process instrument control scheme of the pre-flash energy-saving method is as follows:

[0076] 1. Selection of main instruments

[0077] (1) Feed temperature: integrated temperature transmitter; actuator: preheater gas phase solvent outlet regulating valve; interlocking logic: when the feed temperature exceeds the limit (≥120℃), close the glue liquid feed regulating valve and open the preheater gas phase solvent outlet regulating valve.

[0078] (2) Pre-flash tank pressure: pressure transmitter; actuator: pressure regulating valve, vacuum pump; interlock logic: when the pressure rises, the vacuum pump power is increased; when the pressure is ≥0.02MPa, the vent interlock is triggered and the safety valve is started.

[0079] (3) Feed flow: Coriolis mass flowmeter; Actuator: Glue liquid feed regulating valve, vacuum pump; Interlocking logic: When the flow is abnormal (±10%), the process alarm is triggered and the vacuum pump adjusts the frequency synchronously.

[0080] (4) Liquid level in pre-flash tank: radar level gauge; actuator: glue liquid feed pump frequency converter; interlocking logic: when the liquid level is ≤20%, the pump is stopped; when the liquid level is ≥70%, the glue liquid feed regulating valve is closed and the glue liquid feed pump frequency converter power is increased.

[0081] (5) Oil cooler condensate temperature: integrated temperature transmitter; actuator: circulating water return flow control valve; interlocking logic: when the condensate temperature is too high, open the circulating water return flow control valve.

[0082] 2. Control loop design

[0083] (1) Temperature-pressure cascade control: Main circuit: pre-flash tank pressure control (the set value is determined according to the boiling point of the solvent); Secondary circuit: preheater outlet temperature control to ensure that the temperature is adjusted synchronously when the pressure is adjusted.

[0084] (2) Liquid level-flow feedforward control: predict the feed demand according to the liquid level change, adjust the glue liquid feed valve opening in advance, and reduce the liquid level fluctuation.

[0085] (3) Safety interlock system: When the pressure is greater than 0.02MPa, the interlock closes the glue liquid feed regulating valve and starts emergency pressure relief; when the liquid level is greater than 80%, the interlock stops the pump and alarms.

[0086] 3. Process parameters

[0087] (1) Feed temperature: set value: 85℃; fluctuation range: ±2℃.

[0088] (2) Pre-flash tank pressure: set value: -0.07MPa; fluctuation range: ±5kPa.

[0089] (3) Feed flow rate: set according to the device load.

[0090] (4) Pre-flash tank liquid level: set value: 40%; fluctuation range: ±5%.

[0091] An embodiment of the present invention provides a pre-flash energy-saving method for a coagulation system of an SSBR production device. The embodiment takes lithium-based anionic polymer SSBR as an example. The solvent is cyclohexane and n-hexane prepared in a mass ratio of 9:1. The boiling point of cyclohexane is 80.7°C, and the boiling point of n-hexane is 69°C.

[0092] Example 1: After polymerization, the temperature of the latex solution was 70°C-80°C. After recovering the waste heat (80°C-120°C) from the solvent flash vapor phase in a latex solution preheater, the latex solution temperature rose to 85°C. The solvent flashed at a rate of 65 wt% at a feed rate of 40 m³ / h. The latex solution after flashing was mixed with sodium stearate, a dispersant, and then passed into a coagulation kettle where steam stripping was introduced to further recover the solvent from the latex solution. The solution was then sent to a post-processing unit for drying. The coagulation kettle pressure was 10 kPa-15 kPa, and the temperature was 100°C-120°C.

[0093] The results were: solvent oil consumption was 13.7 kg / ton rubber, and steam consumption was 2.08 tons / ton rubber.

[0094] Comparative Example 1: After the polymerization is completed, the temperature of the glue solution is 70℃-80℃. The glue solution is heated to 120℃ through a heat exchanger (external heat source). The flash evaporation amount of the solvent is 40wt%. 3 The particles are pumped into coagulation reactor I at a flow rate of / h. The reactor is filled with sodium polycarboxylate, sodium oleate, or sodium stearate as a dispersant, accounting for about 0.4% of the dry rubber mass. The particles remain in coagulation reactor I for 20 minutes. Then, they are pumped into coagulation reactor II by a particle pump. The particles remain in coagulation reactor II for 20 minutes. The particles are then sent to the post-processing unit for drying. The temperature of coagulation reactor I is controlled at 98°C and the pressure is between -0.05MPa and 0.09MPa. The temperature of coagulation reactor II is controlled at 101°C and the pressure is between 0MPa and 0.09MPa.

[0095] The results are: solvent oil consumption is 15kg / ton rubber, and steam consumption is 2.8 tons / ton rubber.

[0096] Comparative Example 2: After the polymerization is completed, the temperature of the rubber solution is about 70℃-80℃, the feed flow rate is 40m³ / h, and it is directly injected into the coagulation kettle, and steam is introduced for stripping. The pressure of the coagulation kettle is 10kPa-15kPa, and the temperature is 100℃-120℃. After removing the solvent, it is sent to the post-processing unit for dehydration and drying.

[0097] The results are: solvent oil consumption is 96kg / ton rubber, and steam consumption is 5.6 tons / ton rubber.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A pre-flash energy-saving method for a condensation system of an SSBR production device, characterized in that: The condensation system includes a pre-flash tank, a glue preheater, an oil cooler, a vacuum pump, a glue feed pump, a condensation kettle, and an oil-water separation tank; the pre-flash energy-saving method includes the following steps: S10, preheating the glue solution from the polymerization system to a set temperature through the glue solution preheater; the heat source of the glue solution preheater is the gas phase solvent after flash evaporation, and the set temperature of the glue solution preheater is 80° C.-100° C.; S20, feeding the preheated glue solution into the pre-flash tank, sucking out the gaseous solvent at the top of the pre-flash tank by the vacuum pump, so that the pressure in the pre-flash tank is maintained at a slightly negative pressure; the glue solution at the bottom of the pre-flash tank is fed to the coagulation kettle by the glue solution feed pump; the flashing amount of the glue solution at the bottom of the pre-flash tank is controlled to be 65%-80%; the residence time of the glue solution in the pre-flash tank is 120 seconds; The gaseous solvent sucked out by the vacuum pump enters the glue liquid preheater for primary heat exchange, and then enters the oil cooler for secondary heat exchange to recover the steam waste heat of the gaseous solvent; Wherein, the pressure range of the micro-negative pressure is -0.08MPa to 0.01MPa; The coagulation kettle includes a first kettle, a middle kettle and a last kettle. The heavy component A is sent from the bottom of the first kettle to the middle kettle, the heavy component B is sent from the bottom of the middle kettle to the last kettle, the glue liquid at the bottom of the last kettle is sent to the glue liquid discharge port, the light component A is sent from the top of the first kettle to the oil-water separation tank, the light component B is sent from the top of the middle kettle to the first kettle, and the light component C is sent from the top of the last kettle to the first kettle; the water separated in the oil-water separation tank is sent to the hot water feed port, and the hot water feed port is connected to the first kettle, wherein the pressure of the coagulation kettle is 10kPa-15kPa; The pre-flash tank includes a pressure transmitter, a pressure regulating valve, a flow meter, and a feed regulating valve; a logic interlock control is formed between the pressure transmitter, the pressure regulating valve, and the vacuum pump; a logic interlock control is formed between the flow meter, the feed regulating valve, and the vacuum pump.

2. The pre-flash energy-saving method according to claim 1, characterized in that: In the S20, the glue liquid at the bottom of the pre-flash tank is sent to the static mixer through the glue liquid feed pump, mixed with the dispersant, and then sent to the coagulation kettle; Wherein, the dispersant includes sodium polycarboxylate, sodium oleate or sodium stearate.

3. The pre-flash energy-saving method according to claim 1, characterized in that: After the gas phase solvent passes through the oil cooler for secondary heat exchange, the condensed liquid phase solvent flows into the solvent buffer tank, and the non-condensable gas in the oil cooler is introduced into the tail gas collection system.

4. The pre-flash energy-saving method according to claim 1, characterized in that: The condensation system is provided with a temperature-pressure cascade control system for adjusting the outlet temperature of the glue preheater synchronously when adjusting the pressure of the pre-flash tank; The temperature-pressure cascade control system includes a main loop and a sub-loop, wherein the main loop is used to control the pressure of the pre-flash tank, and the sub-loop is used to control the outlet temperature of the glue preheater.

5. The pre-flash energy-saving method according to claim 1, characterized in that: The preheater includes a first temperature transmitter and a gas phase solvent outlet regulating valve; The pre-flash tank includes a pressure transmitter, a pressure regulating valve, a flow meter, a feed regulating valve, and a liquid level gauge; The oil cooler includes a second temperature transmitter and a return water flow regulating valve.

6. The pre-flash energy-saving method according to claim 5, characterized in that: A logical interlock control is formed between the first temperature transmitter and the gas phase solvent outlet regulating valve; A logical interlock control is formed between the pressure transmitter, the pressure regulating valve and the vacuum pump; A logical interlock control is formed between the flow meter, the feed regulating valve and the vacuum pump; A logical interlock control is formed between the liquid level meter and the glue liquid feed pump; A logical interlock control is formed between the second temperature transmitter and the return water flow regulating valve.

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