A high-efficiency energy-saving double-effect concentration method and system

Abstract

The application discloses a kind of high-efficiency energy-saving double-effect concentration method and system, belong to biological medicine and chemical raw material extraction separation technical field.Raw material liquid is filtered, and after three-stage preheating and cooling unit and one-effect front column heat exchanger is sent into one-effect, two-effect concentration separator respectively.One-effect evaporator, the condensate of each column heat exchanger and two-effect evaporation pipe residual gas are sent into three-stage, two-stage and one-stage spiral plate heat exchanger respectively according to ladder, and the raw material liquid is carried out continuous three-stage ladder preheating, realizes residual heat efficient recovery;One-effect and two-effect concentration separator use three-section concentration separation structure, raw material is separated after atomization spraying in upper large space negative pressure flash evaporation, middle part uses the heat exchange evaporation of large specific surface area ladder type evaporator, and bottom liquid is circulated and physically defoamed.The application does not need high-speed precision equipment such as heat pump, production efficiency is high, residual heat is fully utilized, suitable for complex working conditions such as high salt and high viscosity, and maintenance is simple.

Description

Technical Field

[0001] This invention relates to the field of extraction and separation technology of biopharmaceutical, traditional Chinese medicine and chemical raw materials, and in particular to a highly efficient and energy-saving dual-effect concentration method and system. Background Technology

[0002] High-efficiency evaporation and concentration technology, with its energy-saving, rapid, and gentle characteristics, was initially widely used in conventional processes such as solvent recovery, solution concentration, and product separation in the chemical, pharmaceutical, and fine chemical industries. With technological iteration and equipment upgrades, its application has deeply penetrated into modern manufacturing industries with stringent requirements for product activity, quality, and environmental protection, covering fields such as pharmaceuticals and biotechnology, food and beverage, and environmental protection and resource recycling. It has become a key common technology in modern industry for improving product quality, ensuring process safety, and achieving green production.

[0003] In the chemical and fine chemical production fields, large-scale industrial concentration processes often face extreme conditions such as high-boiling-point materials, highly corrosive media, high-viscosity systems, and severe scaling tendencies. This requires evaporation and concentration equipment to possess corrosion-resistant materials, anti-clogging structures, and efficient anti-scaling designs, while simultaneously meeting the requirements of low energy consumption and long-term stable operation under high-throughput continuous operation. In the fields of traditional Chinese medicine extraction and biopharmaceutical production, equipment is required to maximize the retention of heat-sensitive active ingredients such as flavonoids, saponins, and polysaccharides while achieving low cost and high efficiency. Alternatively, it may employ short-time, low-temperature evaporation to prevent the denaturation of bioactive substances such as antibiotics, vitamins, vaccines, enzymes, and proteins, ensuring the efficacy and safety of the final drug. This presents significantly different and extremely stringent technical challenges to the thermal design, temperature control accuracy, material selection, and operational reliability of evaporation and concentration equipment.

[0004] The current mainstream high-efficiency evaporation and concentration technologies mainly include mechanical vapor recompression (MVR), heat pumps, and dual-effect or even multi-effect evaporation and concentration. However, under the stringent requirements of modern industrial production, these technologies still have certain limitations.

[0005] (i) MVR technology faces problems such as high investment costs, easy scaling and clogging of heat transfer surfaces, abnormal energy consumption due to increased boiling point, and stringent water quality requirements. For example, the core equipment of the MVR system - the steam compressor (centrifugal or Roots type) is expensive. In addition, the supporting heat exchanger, crystallizer and precision control system make its overall cost usually 1.5 to 3 times that of traditional multi-effect evaporation equipment.

[0006] (ii) Heat pump technology also faces challenges such as high initial investment costs, high complexity of technology implementation and control, energy efficiency being easily affected by the environment and operating conditions, and challenges in system integration and matching. For example, in concentration processes that require high vacuum (such as the extraction of traditional Chinese medicine), the introduction of a heat pump system may make it more difficult to control the vacuum level stably, increasing the difficulty of operation. When the ambient temperature (or heat source temperature) is extremely low, the coefficient of performance (COP) of the heat pump will decrease significantly, and the energy-saving advantage will be severely weakened. In particular, compared with direct electric heating or steam heating, the heating process of the heat pump is relatively mild and slow, which is not advantageous in production lines that require rapid start-up or frequent changes in operating conditions.

[0007] (III) Multi-effect concentration also faces significant challenges in balancing energy efficiency and economy, retaining heat-sensitive active ingredients, and improving heat transfer efficiency. For example, in conventional two / three-effect designs, the heat transfer driving force of the second / third effect decreases due to the gradual decay of secondary steam temperature and pressure, resulting in low evaporation efficiency and creating the awkward situation that "the equipment investment is for two / three effects, but the output is only equivalent to one / two and a half effects".

[0008] Therefore, current evaporation and concentration equipment and technologies cannot simultaneously meet the requirements of modern Chinese medicine extraction, biological agents or chemical production for low cost, low energy consumption, high efficiency and easy maintenance. There is an urgent need for a new type of high-efficiency and energy-saving evaporation and concentration method and system that combines high thermal efficiency, low production cost and energy consumption, easy maintenance and can ensure high-quality production to solve the above problems. Summary of the Invention

[0009] The present invention aims to at least improve one of the technical problems existing in the prior art. To this end, the present invention proposes a highly efficient and energy-saving dual-effect concentration method and system.

[0010] The technical solution of the present invention is as follows: A highly efficient and energy-saving dual-effect concentration method, comprising: After passing through a filter, the raw liquid is fed into a first-effect concentration separator and a second-effect concentration separator through a continuous three-stage preheating and cooling unit and a first-effect pre-tube heat exchanger, respectively. This is to quickly preheat the raw liquid to reduce the energy consumption of the first-effect and second-effect concentration separation. The three-stage preheating and cooling unit includes a first-stage condensation collection heating tank and a first-stage spiral plate heat exchanger, a second-stage spiral plate heat exchanger and a third-stage spiral plate heat exchanger connected in sequence. After the raw liquid in the first-effect and second-effect thickeners reaches the target limit level, a double-effect evaporation and concentration process is performed, and evaporation and concentration at different temperatures are achieved by using vacuum control. Steam undergoes heat exchange in the first-effect evaporator via the main steam pipe. The steam then undergoes heat exchange with the first-effect pre-evaporator via the heated steam pipe. The condensate discharged from each heat exchanger is then combined and enters a three-stage spiral plate heat exchanger for three-stage preheating of the feed liquid. The residual water after three-stage preheating enters the second-effect evaporator to preheat the feed liquid before atomization spraying in the second-effect evaporation and concentration process. Finally, the wastewater after heat exchange in the second-effect evaporator is discharged through the drain pipe. The steam separated in the first-effect evaporation and concentration process is transported to the second-effect evaporation and concentration process under negative pressure through the first-effect evaporation tube. The condensate formed after heat exchange is used to preheat the raw material liquid in the second stage through the second-stage spiral plate heat exchanger, and the residual water after the second stage preheating is stored in the first-stage condensate collection and heating tank. The steam separated in the double-effect evaporation and concentration process is transported to the first-stage spiral plate heat exchanger under negative pressure through the double-effect evaporation tube to complete the first preheating of the raw material liquid. The cooling water after the first preheating is stored in the second-stage condensation collection tank.

[0011] In one possible technical solution, the double-effect evaporation and concentration process further includes a first-effect evaporation and concentration process and a second-effect evaporation and concentration process. The first-effect evaporation and concentration process is performed using a first-effect concentration and separation unit, which includes a first-effect pre-tube heat exchanger, a first-effect concentration separator, a first-effect feed liquid circulation pump, a first-effect tube heat exchanger, a first-effect atomizing spray, and a first-effect evaporation tube. The single-effect evaporation and concentration process specifically includes: Turn on the first-effect raw material circulation pump, main steam valve and heating steam valve. The raw material liquid inside the first-effect concentrator enters the first-effect atomizing spray for tube spraying through the first-effect raw material circulation pump and the first-effect tube heat exchanger. The first-effect concentrator achieves stage-by-stage evaporation and concentration on the large specific surface area evaporator. The bottom concentrate is returned through the first-effect raw material circulation pump to repeat the process. When the temperature inside the first-effect thickener reaches the first preset range, turn on the water ring vacuum pump and open the vacuum valve of the first-effect thickener, and adjust the vacuum degree of the first-effect thickener to the first preset parameter range.

[0012] In one possible technical solution, a double-effect concentration and separation unit is further employed to perform the double-effect evaporation and concentration process. This double-effect concentration and separation unit includes a double-effect concentration separator, a double-effect feed liquid circulation pump, a double-effect shell-and-tube heat exchanger, a double-effect atomizing spray system, and double-effect evaporation tubes. The specific steps of the double-effect evaporation and concentration process are as follows: Turn on the second-effect feed liquid circulation pump so that the feed liquid in the second-effect thickener is transported to the first-effect atomizing spray for tube spraying via the second-effect feed liquid circulation pump and the second-effect shell and tube heat exchanger; the large specific surface area evaporator in the second-effect shell and tube heat exchanger achieves stage-by-stage evaporation and concentration, and the bottom concentrate is returned through the second-effect feed liquid circulation pump to repeat the process. When the temperature inside the double-effect thickener reaches the second preset range, turn on the water ring vacuum pump and open the vacuum valve of the double-effect thickener, and adjust the vacuum level of the double-effect thickener to the second preset parameter range.

[0013] In one possible technical solution, the double-effect evaporation and concentration process further includes: After the first-effect evaporation and concentration process and the second-effect evaporation and concentration process have been running normally for a certain period of time, adjust the opening of the main steam valve and the heating steam valve to control the pressure within the target pressure threshold range. Monitor whether the temperature, pressure, flow rate and vacuum level of each control point are within the target normal range. If not, make corrections to bring each indicator to the target normal range.

[0014] In one possible technical solution, the double-effect evaporation and concentration process further includes a self-cleaning process, specifically: Determine whether the finished products of the first-effect concentrated product and the second-effect concentrated product meet the product standards. If so, stop the feed pump, the first-effect raw material circulation pump and the second-effect raw material circulation pump, the water ring vacuum pump, and the main steam and heating steam valves in sequence. Initiating the self-cleaning process: Inject cleaning solvent, turn on the first-effect raw material circulation pump and the second-effect raw material circulation pump to circulate the cleaning solvent in the first-effect and second-effect concentrators and their respective pipelines, flushing and dissolving the residual liquid adhering to the pipe walls and the inner walls of the concentrators; after circulation cleaning, open the drain valve to discharge the cleaning waste liquid containing impurities, and then repeat the rinsing process several times with clean solvent until the discharged liquid is clear and free of impurities; after cleaning is completed, turn off all circulation pumps and valves to complete the entire self-cleaning operation and wait for the next production start-up.

[0015] In one possible technical solution, the first-effect evaporator has the same structure as the second-effect evaporator, having a shell with a three-section evaporation structure inside to divide the inner cavity of the shell into three connected working areas. A stepped evaporator is installed in the middle section, and each evaporator has a large specific surface area for heat exchange evaporation.

[0016] In one possible technical solution, the steam separated by the first-effect condenser further enters the second-effect condenser via the first-effect evaporator tube, and the steam separated by the second-effect condenser enters the first-stage spiral plate heat exchanger via the second-effect evaporator tube; the three-stage condensation and separation structure also includes: The upper section is where the preheated raw material inlet enters the concentrator via a distributed ring diversion system, and an atomizing spray is installed below the preheated raw material inlet. The lower section is the raw liquid circulation and storage area. After heat exchange and evaporation, the raw liquid is physically defoamed and then sent to the tube heat exchanger for further heating through the raw liquid circulation pump. Afterwards, it is atomized and sprayed in the upper section to form small droplets.

[0017] In one possible technical solution, the further step of storing the residual water after secondary preheating in the primary condensate collection and heating tank specifically includes: During normal operation, the pneumatic valve of the primary condensate collection and heating tank is opened, and the condensate produced after heat exchange by the secondary spiral plate heat exchanger can automatically flow into the primary condensate collection and heating tank. When the condensate level in the primary condensate collection and heating tank reaches the set value, the pneumatic valve is closed and the condensate in the tank is discharged for other uses.

[0018] In one possible technical solution, the step of storing the preheated cooling water in a secondary condensate collection tank further includes: During normal operation, the pneumatic valve of the secondary condensate collection tank is opened, allowing the condensate generated by the heat exchange of the condenser in the tank to automatically flow into the tank. When the condensate level in the tank reaches the set value, the pneumatic valve is closed and the condensate is discharged for other uses.

[0019] A high-efficiency and energy-saving dual-effect concentration system is provided to implement the high-efficiency and energy-saving dual-effect concentration method.

[0020] The efficient and energy-saving dual-effect concentration method and system of the present invention have the following advantages compared with the prior art: 1. Significantly reduce system energy consumption and achieve efficient cascade utilization of waste heat. This invention, through process innovation, utilizes the condensate from the first-effect evaporator, the condensate from the first-effect pre-tube heat exchanger, the condensate from the first-effect tube heat exchanger, the condensate from the second-effect evaporator, the condensate from the second-effect tube heat exchanger, and the waste gas from the second-effect evaporator tubes as a heat source to continuously preheat the raw material liquid in three stages. This design significantly improves the system's waste heat recovery and utilization rate, effectively reducing the need for external heat sources, thereby significantly reducing the overall energy consumption of the system.

[0021] 2. Significantly improves evaporation and separation efficiency, and enhances mass and heat transfer processes. This invention features an original three-section structural design for single-effect and double-effect concentrators. The bottom liquid accumulation zone effectively suppresses foam entrainment through forced circulation combined with mechanical defoaming; the middle atomizing spray zone employs a stepped, large specific surface area structure to enhance heat and mass transfer efficiency under low-temperature evaporation conditions; and the upper large-space area utilizes droplet suspension evaporation to significantly extend the gas-liquid separation path. The synergistic effect of these three parts greatly improves the processing capacity per unit time and overall production efficiency.

[0022] 3. Optimize system configuration to improve adaptability to harsh operating conditions and ease of operation and maintenance. Compared to existing technologies that rely on high-speed, precision equipment such as compressors or steam jet heat pumps, the system structure of this invention is simpler and the initial investment cost is lower. The entire system is equipped with only a circulating pump and low-speed defoaming machinery, without complex high-speed rotating parts. This not only significantly enhances corrosion resistance and operational stability under harsh conditions such as high salt and high viscosity, but also reduces equipment failure rate, making daily cleaning and maintenance operations simpler and effectively extending equipment lifespan.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a process flow diagram of the high-efficiency and energy-saving dual-effect concentration method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a concentrator separator according to an embodiment of the present invention. Detailed Implementation

[0026] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0027] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, it may include a series of steps or units, or optionally, steps or units not listed, or other steps or units inherent to these processes, methods, products, or devices.

[0030] The accompanying drawings show only the portions relevant to this application, not all of them. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations may be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0031] The terms “component,” “module,” “system,” “unit,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a unit can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or distributed between two or more computers. Furthermore, these units can be executed from various computer-readable media on which various data structures are stored. Units can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from a second unit interacting with another unit between a local system, a distributed system, and / or a network; for example, the Internet interacting with other systems via signals).

[0032] Example 1 like Figure 1 and Figure 2 As shown, this embodiment provides a highly efficient and energy-saving dual-effect concentration method, which includes: After passing through a filter, the raw liquid is fed into a first-effect concentration separator and a second-effect concentration separator through a continuous three-stage preheating and cooling unit and a first-effect pre-tube heat exchanger, respectively. This is to quickly preheat the raw liquid to reduce the energy consumption of the first-effect and second-effect concentration separation. The three-stage preheating and cooling unit includes a first-stage condensation collection heating tank and a first-stage spiral plate heat exchanger, a second-stage spiral plate heat exchanger and a third-stage spiral plate heat exchanger connected in sequence. After the raw liquid in the first-effect and second-effect thickeners reaches the target limit level, a double-effect evaporation and concentration process is performed, and evaporation and concentration at different temperatures are achieved by using vacuum control. Steam undergoes heat exchange in the first-effect evaporator via the main steam pipe. The steam then undergoes heat exchange with the first-effect pre-evaporator via the heated steam pipe. The condensate discharged from each heat exchanger is then combined and enters a three-stage spiral plate heat exchanger for three-stage preheating of the feed liquid. The residual water after three-stage preheating enters the second-effect evaporator to preheat the feed liquid before atomization spraying in the second-effect evaporation and concentration process. Finally, the wastewater after heat exchange in the second-effect evaporator is discharged through the drain pipe. The steam separated in the first-effect evaporation and concentration process is transported to the second-effect evaporation and concentration process under negative pressure through the first-effect evaporation tube. The condensate formed after heat exchange is used to preheat the raw material liquid in the second stage through the second-stage spiral plate heat exchanger, and the residual water after the second stage preheating is stored in the first-stage condensate collection and heating tank. The steam separated in the double-effect evaporation and concentration process is transported to the first-stage spiral plate heat exchanger under negative pressure through the double-effect evaporation tube to complete the first preheating of the raw material liquid. The cooling water after the first preheating is stored in the second-stage condensation collection tank.

[0033] It should be noted that, in this embodiment, the double-effect evaporation and concentration process includes a first-effect evaporation and concentration process and a second-effect evaporation and concentration process. The first-effect evaporation and concentration process is performed by a first-effect concentration and separation unit, which includes a first-effect pre-tube heat exchanger, a first-effect concentration separator, a first-effect feed liquid circulation pump, a first-effect tube heat exchanger, a first-effect atomizing spray, and a first-effect evaporation tube. The single-effect evaporation and concentration process specifically includes: Turn on the first-effect raw material circulation pump, main steam valve and heating steam valve. The raw material liquid inside the first-effect concentrator enters the first-effect atomizing spray for tube spraying through the first-effect raw material circulation pump and the first-effect tube heat exchanger. The first-effect concentrator achieves stage-by-stage evaporation and concentration on the large specific surface area evaporator. The bottom concentrate is returned through the first-effect raw material circulation pump to repeat the process. When the temperature inside the first-effect thickener reaches the first preset range, turn on the water ring vacuum pump and open the vacuum valve of the first-effect thickener, and adjust the vacuum degree of the first-effect thickener to the first preset parameter range.

[0034] It should be noted that, in this embodiment, a double-effect concentration and separation unit is used to perform the double-effect evaporation and concentration process. This double-effect concentration and separation unit includes a double-effect concentration separator, a double-effect feed liquid circulation pump, a double-effect shell-and-tube heat exchanger, a double-effect atomizing spray, and double-effect evaporation tubes. The specific steps of the double-effect evaporation and concentration process are as follows: Turn on the second-effect feed liquid circulation pump so that the feed liquid in the second-effect thickener is transported to the first-effect atomizing spray for tube spraying via the second-effect feed liquid circulation pump and the second-effect shell and tube heat exchanger; the large specific surface area evaporator in the second-effect shell and tube heat exchanger achieves stage-by-stage evaporation and concentration, and the bottom concentrate is returned through the second-effect feed liquid circulation pump to repeat the process. When the temperature inside the double-effect thickener reaches the second preset range, turn on the water ring vacuum pump and open the vacuum valve of the double-effect thickener, and adjust the vacuum level of the double-effect thickener to the second preset parameter range.

[0035] It should be noted that, in this embodiment, the double-effect evaporation and concentration process further includes: After the first-effect evaporation and concentration process and the second-effect evaporation and concentration process have been running normally for a certain period of time, adjust the opening of the main steam valve and the heating steam valve to control the pressure within the target pressure threshold range. Monitor whether the temperature, pressure, flow rate and vacuum level of each control point are within the target normal range. If not, make corrections to bring each indicator to the target normal range.

[0036] It should be noted that, in this embodiment, the double-effect evaporation and concentration process further includes a self-cleaning process, specifically: Determine whether the finished products of the first-effect concentrated product and the second-effect concentrated product meet the product standards. If so, stop the feed pump, the first-effect raw material circulation pump and the second-effect raw material circulation pump, the water ring vacuum pump, and the main steam and heating steam valves in sequence. Initiating the self-cleaning process: Inject cleaning solvent, turn on the first-effect raw material circulation pump and the second-effect raw material circulation pump to circulate the cleaning solvent in the first-effect and second-effect concentrators and their respective pipelines, flushing and dissolving the residual liquid adhering to the pipe walls and the inner walls of the concentrators; after circulation cleaning, open the drain valve to discharge the cleaning waste liquid containing impurities, and then repeat the rinsing process several times with clean solvent until the discharged liquid is clear and free of impurities; after cleaning is completed, turn off all circulation pumps and valves to complete the entire self-cleaning operation and wait for the next production start-up.

[0037] It should be noted that in this embodiment, the first-effect evaporator has the same structure as the second-effect evaporator, with a shell. The shell adopts a three-section evaporation structure to divide the inner cavity of the shell into three connected working areas. A stepped evaporator is installed in the middle section, and each evaporator has a large specific surface area for heat exchange evaporation.

[0038] It should be noted that, in this embodiment, the steam separated by the first-effect condenser enters the second-effect condenser via the first-effect evaporator, and the steam separated by the second-effect condenser enters the first-stage spiral plate heat exchanger via the second-effect evaporator; the three-stage condensation and separation structure further includes: The upper section is where the preheated raw material inlet enters the concentrator via a distributed ring diversion system, and an atomizing spray is installed below the preheated raw material inlet. The lower section is the raw liquid circulation and storage area. After heat exchange and evaporation, the raw liquid is physically defoamed and then sent to the tube heat exchanger for further heating through the raw liquid circulation pump. Afterwards, it is atomized and sprayed in the upper section to form small droplets.

[0039] It should be noted that, in this embodiment, the process of storing the residual water after secondary preheating in the primary condensate collection and heating tank specifically includes: During normal operation, the pneumatic valve of the primary condensate collection and heating tank is opened, and the condensate produced after heat exchange by the secondary spiral plate heat exchanger can automatically flow into the primary condensate collection and heating tank. When the condensate level in the primary condensate collection and heating tank reaches the set value, the pneumatic valve is closed and the condensate in the tank is discharged for other uses.

[0040] It should be noted that, in this embodiment, the step of storing the preheated cooling water in the secondary condensate collection tank includes: During normal operation, the pneumatic valve of the secondary condensate collection tank is opened, allowing the condensate generated by the heat exchange of the condenser in the tank to automatically flow into the tank. When the condensate level in the tank reaches the set value, the pneumatic valve is closed and the condensate is discharged for other uses.

[0041] It should be noted that this embodiment features a multi-stage baffle vapor-liquid separation assembly in the upper part of the shell cavity. As the atomized droplets fall, they collide with each stage of the baffles, trapping and collecting residual droplets. The vapor then rises through the baffle gaps, achieving initial vapor-liquid separation. The collected raw material liquid flows to the lower raw material circulation storage area, where it re-partitions into heat exchange and evaporation. Through zoned, controllable spraying and a rationally designed separation and settling height within the dual-effect chamber, the atomized droplets rapidly vaporize and form a uniform thin liquid film on the outer wall of the horizontal heat exchange tube, ensuring continuous evaporation. Combined with a layered, independent hydrophobic structure, condensate accumulation is prevented from affecting heat exchange efficiency, thus maintaining high-efficiency heat exchange and evaporation performance over the long term and significantly improving production efficiency.

[0042] It should be noted that in this embodiment, the physical defoaming adopts a low-speed mechanical defoaming device. This device relies on its own low-speed rotating impeller to generate a shearing effect on the passing mixed fluid, breaking up the bubbles carried in the fluid, achieving gentle defoaming, and avoiding the destruction of the effective components in the raw material liquid during the defoaming process.

[0043] This embodiment provides a high-efficiency and energy-saving dual-effect concentration system, which is used to implement the high-efficiency and energy-saving dual-effect concentration method described above.

[0044] This embodiment provides the following implementation example, as detailed below. S1: Start the feed pump and send the feed liquid through the filter, first-stage spiral plate heat exchanger, second-stage spiral plate heat exchanger, third-stage spiral plate heat exchanger, and first-effect pre-tube heat exchanger to the first-effect concentrator and second-effect concentrator respectively, until the feed liquid in each concentrator reaches the target limit level. S2: Turn on the first-effect raw material circulation pump, main steam valve and heating steam valve. When the temperature inside the first-effect concentrator rises to 80℃~90℃, start the water ring vacuum pump and then open the vacuum valve of the first-effect concentrator. Adjust the vacuum degree of the first-effect concentrator to -0.04Mpa ~ -0.06Mpa. S3: When the temperature inside the double-effect thickener rises to 70℃~75℃, turn on the double-effect feed liquid circulation pump and the vacuum valve of the double-effect thickener, and adjust the vacuum degree of the double-effect thickener to -0.07Mpa ~-0.08Mpa. S4: After the system has run for the specified time, control the opening of the main steam valve and the heating steam valve to a specific pressure range of 0.1 MPa to 0.3 MPa; S5: Check whether the parameters such as temperature, pressure, flow rate, and vacuum at each control point of the system are within the normal operating range and correct them in a timely manner; S6: When the finished products of the first-effect concentrated product and the second-effect concentrated product meet the product standards, the feed pump, the first-effect raw material circulation pump and the second-effect raw material circulation pump, the water ring vacuum pump, the main steam and heating steam valves are closed in sequence. The finished products are collected and moved outside the system, and then the system self-cleaning process is started.

[0045] Actual production tests conducted by Li Shizhen Pharmaceutical Group Co., Ltd. demonstrate that the high-efficiency concentration method, equipment, and process based on this invention patent can be highly energy-efficient and significantly improve production efficiency. Relevant test data are shown in Table 1. Actual production test data shows that, with an initial raw material temperature of 40℃, two batches of 5 tons of Leonurus japonicus, after 2.01 and 2.50 hours of continuous production respectively, achieved first-effect / second-effect production capacities of 2.359 tons / 2.026 tons and 2.246 tons / 1.935 tons, respectively, with extract densities of 1.07 and 1.20, steam consumption of 0.714 and 0.769 tons, evaporation rates of 2.48 tons / hour and 2.00 tons / hour, and energy consumption ratios of 1:7 and 1:6.5, respectively. Meanwhile, a single batch of 5.3 tons of Prunella vulgaris decoction at 40℃, after 1.9 hours of continuous production, achieved first-effect / second-effect production capacities of 2.500 tons / 2.148 tons, with an extract density of 1.06, steam consumption of 0.706 tons, evaporation rate of 2.79 tons / hour, and an energy consumption ratio of 1:7.5.

[0046] Table 1. Concentration test data of Leonurus japonicus decoction, Prunella vulgaris decoction and water The present invention is summarized below compared with the prior art, taking a processing capacity of 2 tons as an example, as shown in Table 2. Table 2. Comparison of the overall performance of the present invention and the prior art In summary, this invention can process high-viscosity, easily foaming, heat-sensitive materials, bio-fertilizers, and traditional Chinese medicine extracts, etc. It is anti-scaling, does not easily dry out the walls, maintains high heat-sensitive components of materials, has a wide operating range adaptable to loads, and can reduce the initial equipment investment cost by 15% to 40% compared with TVR and MVR. It consumes less electricity and gas per ton of water, saves cooling water, has low maintenance and upkeep costs, and has a high overall cost-performance ratio.

[0047] The efficient and energy-saving dual-effect concentration method and system of the present invention have the following advantages compared with the prior art: 1. Significantly reduce system energy consumption and achieve efficient cascade utilization of waste heat. This invention, through process innovation, utilizes the condensate from the first-effect evaporator, the condensate from the first-effect pre-tube heat exchanger, the condensate from the first-effect tube heat exchanger, the condensate from the second-effect evaporator, the condensate from the second-effect tube heat exchanger, and the waste gas from the second-effect evaporator tubes as heat sources to continuously preheat the raw material liquid in three stages. This design significantly improves the system's waste heat recovery and utilization rate, effectively reducing the need for external heat sources, thereby significantly reducing the overall process energy consumption.

[0048] 2. Significantly improves evaporation and separation efficiency, and enhances mass and heat transfer processes. This invention features an original three-section structural design for single-effect and double-effect concentrators. The bottom liquid accumulation zone effectively suppresses foam entrainment through forced circulation combined with mechanical defoaming; the middle atomizing spray zone employs a stepped, large specific surface area structure to enhance heat and mass transfer efficiency under low-temperature evaporation conditions; and the upper large-space area utilizes droplet suspension evaporation to significantly extend the gas-liquid separation path. The synergistic effect of these three parts greatly improves the processing capacity per unit time and overall production efficiency.

[0049] 3. Optimize system configuration to improve adaptability to harsh operating conditions and ease of operation and maintenance. Compared to existing technologies that rely on high-speed, precision equipment such as compressors or steam jet heat pumps, the system structure of this invention is simpler and the initial investment cost is lower. The entire system is equipped with only a circulating pump and low-speed defoaming machinery, without complex high-speed rotating parts. This not only significantly enhances corrosion resistance and operational stability under harsh conditions such as high salt and high viscosity, but also reduces equipment failure rate, making daily cleaning and maintenance operations simpler and effectively extending equipment lifespan.

[0050] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0051] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0052] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0053] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A highly efficient and energy-saving dual-effect concentration method, characterized in that, include: After passing through a filter, the raw liquid is fed into a first-effect concentration separator and a second-effect concentration separator through a continuous three-stage preheating and cooling unit and a first-effect pre-tube heat exchanger, respectively. This is to quickly preheat the raw liquid to reduce the energy consumption of the first-effect and second-effect concentration separation. The three-stage preheating and cooling unit includes a first-stage condensation collection heating tank, a second-stage condensation collection tank, and a first-stage spiral plate heat exchanger, a second-stage spiral plate heat exchanger, and a third-stage spiral plate heat exchanger connected in sequence. After the raw liquid in the first-effect and second-effect thickeners reaches the target limit level, a double-effect evaporation and concentration process is performed, and evaporation and concentration at different temperatures are achieved by using vacuum control. Steam undergoes heat exchange in the first-effect evaporator via the main steam pipe. The steam then undergoes heat exchange with the first-effect pre-evaporator via the heated steam pipe. The condensate discharged from each heat exchanger is then combined and enters a three-stage spiral plate heat exchanger for three-stage preheating of the feed liquid. The residual water after three-stage preheating enters the second-effect evaporator to preheat the feed liquid before atomization spraying in the second-effect evaporation and concentration process. Finally, the wastewater after heat exchange in the second-effect evaporator is discharged through the drain pipe. The steam separated in the first-effect evaporation and concentration process is transported to the second-effect evaporation and concentration process under negative pressure through the first-effect evaporation tube. The condensate formed after heat exchange is used to preheat the raw material liquid in the second stage through the second-stage spiral plate heat exchanger, and the residual water after the second stage preheating is stored in the first-stage condensate collection and heating tank. The steam separated in the double-effect evaporation and concentration process is transported to the first-stage spiral plate heat exchanger under negative pressure through the double-effect evaporation tube to complete the first preheating of the raw material liquid. The cooling water after the first preheating is stored in the second-stage condensation collection tank.

2. The high-efficiency and energy-saving dual-effect concentration method according to claim 1, characterized in that, The dual-effect evaporation and concentration process includes a first-effect evaporation and concentration process and a second-effect evaporation and concentration process. The first-effect evaporation and concentration process is performed by a first-effect concentration and separation unit, which includes a first-effect pre-tube heat exchanger, a first-effect concentration separator, a first-effect feed liquid circulation pump, a first-effect tube heat exchanger, a first-effect atomizing spray, and a first-effect evaporation tube. The single-effect evaporation and concentration process specifically includes: Once the raw material liquid reaches the designated level, the first-effect raw material liquid circulation pump, main steam valve, and heating steam valve are turned on. The raw material liquid inside the first-effect concentrator enters the first-effect atomizing spray pipe through the first-effect raw material liquid circulation pump and the first-effect tube heat exchanger. It is then sprayed on the large specific surface area evaporator in the first-effect concentrator to achieve multiple stages of evaporation and concentration. The bottom concentrate is returned through the first-effect raw material liquid circulation pump to repeat the evaporation and concentration process. When the temperature inside the first-effect thickener reaches the first preset range, turn on the water ring vacuum pump and open the vacuum valve of the first-effect thickener, and adjust the vacuum degree of the first-effect thickener to the first preset parameter range.

3. The high-efficiency and energy-saving dual-effect concentration method according to claim 2, characterized in that, A double-effect concentration and separation unit is used to perform the double-effect evaporation and concentration process. This unit includes a double-effect concentration separator, a double-effect feed liquid circulation pump, a double-effect shell-and-tube heat exchanger, a double-effect atomizing spray system, and double-effect evaporation tubes. The specific steps of the double-effect evaporation and concentration process are as follows: Once the raw material liquid reaches the designated level, the double-effect raw material liquid circulation pump is turned on, so that the material liquid in the double-effect thickener is transported to the double-effect atomizing spray pipe via the double-effect raw material liquid circulation pump and the double-effect shell and tube heat exchanger. The liquid is then sprayed through the double-effect atomizing spray pipe, where it is evaporated and concentrated in stages on the large specific surface area evaporator in the double-effect shell and tube heat exchanger. The concentrated liquid at the bottom is returned through the double-effect raw material liquid circulation pump to repeat the process. When the temperature inside the double-effect thickener reaches the second preset range, turn on the water ring vacuum pump and open the vacuum valve of the double-effect thickener, and adjust the vacuum level of the double-effect thickener to the second preset parameter range.

4. The high-efficiency and energy-saving dual-effect concentration method according to claim 2, characterized in that, The double-effect evaporation and concentration process also includes: After the first-effect evaporation and concentration process and the second-effect evaporation and concentration process have been running normally for a certain period of time, adjust the opening of the main steam valve and the heating steam valve to control the pressure within the target pressure threshold range. Monitor whether the temperature, pressure, flow rate and vacuum level of each control point are within the target normal range. If not, make corrections to bring each indicator to the target normal range.

5. The high-efficiency and energy-saving dual-effect concentration method according to claim 2, characterized in that, The dual-effect evaporation and concentration process also includes a self-cleaning process, specifically: Determine whether the finished products of the first-effect concentrated product and the second-effect concentrated product meet the product standards. If so, stop the feed pump, the first-effect raw material circulation pump and the second-effect raw material circulation pump, the water ring vacuum pump, and the main steam and heating steam valves in sequence. Initiating the self-cleaning process: Inject cleaning solvent, turn on the first-effect raw material circulation pump and the second-effect raw material circulation pump to circulate the cleaning solvent in the first-effect and second-effect concentrators and their respective pipelines, flushing and dissolving the residual liquid adhering to the pipe walls and the inner walls of the concentrators; after circulation cleaning, open the drain valve to discharge the cleaning waste liquid containing impurities, and then repeat the rinsing process several times with clean solvent until the discharged liquid is clear and free of impurities; after cleaning is completed, turn off all circulation pumps and valves to complete the entire self-cleaning operation and wait for the next production start-up.

6. The high-efficiency and energy-saving dual-effect concentration method according to claim 2, characterized in that, The single-effect evaporator has the same structure as the double-effect evaporator. It adopts a three-section evaporation structure to divide the inner cavity of the shell into three connected working areas. The middle section is equipped with a stepped evaporator with a large specific surface area for heat exchange and evaporation.

7. The high-efficiency and energy-saving dual-effect concentration method according to claim 6, characterized in that, The steam separated by the first-effect condenser enters the second-effect condenser through the first-effect evaporator tubes, and the steam separated by the second-effect condenser enters the first-stage spiral plate heat exchanger through the second-effect evaporator tubes; the three-stage condensation and separation structure also includes: The upper section is where the preheated raw material inlet enters the concentrator via a distributed ring diversion system, and an atomizing spray is installed below the preheated raw material inlet. The lower section is the raw liquid circulation and storage area. After heat exchange and evaporation, the raw liquid is physically defoamed and then sent to the tube heat exchanger for further heating through the raw liquid circulation pump. Afterwards, it is atomized and sprayed in the upper section to form small droplets.

8. The high-efficiency and energy-saving dual-effect concentration method according to claim 1, characterized in that, The specific steps for storing the residual water after secondary preheating in the primary condensate collection and heating tank include: During normal operation, the pneumatic valve of the primary condensate collection and heating tank is opened, and the condensate produced after heat exchange by the secondary spiral plate heat exchanger can automatically flow into the primary condensate collection and heating tank. When the condensate level in the primary condensate collection and heating tank reaches the set value, the pneumatic valve is closed and the condensate in the tank is discharged for other uses.

9. The high-efficiency and energy-saving dual-effect concentration method according to claim 1, characterized in that, The process of storing the preheated cooling water in a secondary condensate collection tank includes: During normal operation, the pneumatic valve of the secondary condensate collection tank is opened, allowing the condensate generated by heat exchange in the secondary condensate collection tank to automatically flow into the tank; When the condensate level in the secondary condensate collection tank reaches the set value, the pneumatic valve is closed and the condensate is discharged for other uses.

10. A high-efficiency and energy-saving dual-effect concentration system, characterized in that, Used to implement the high-efficiency and energy-saving dual-effect concentration method as described in any one of claims 1 to 9.

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