Biomass pyrolysis gas selective condenser based on light-temperature coupling interaction real-time regulation

Abstract

The application discloses a biomass pyrolysis gas selective condenser based on light-temperature coupling interaction real-time regulation and control, which comprises a plurality of unit composite condensing systems, a light-temperature coupling real-time monitoring system, a cooling capacity intelligent regulation and control system and a bio-oil storage system, wherein the plurality of unit composite condensing systems are used as reaction sites for condensing biomass pyrolysis gas; the light-temperature coupling real-time monitoring system is arranged before and after each unit composite condensing system; light-temperature monitoring data is transmitted to the cooling capacity intelligent regulation and control system after being integrated by the system; the regulation and control system is simultaneously linked with direct condensing and indirect condensing control valves in the unit composite condensing system and is used for automatically regulating and controlling the cooling capacity of the condensing device; and liquid products obtained by cooling the pyrolysis gas are finally recovered and stored in the bio-oil storage system. According to the light-temperature coupling real-time monitoring data, the application can automatically adjust the cooling capacity of the condenser, realizes fine biomass pyrolysis gas selective condensation and high-quality bio-oil preparation.

Description

TECHNICAL FIELD

[0001] The application relates to a biomass pyrolysis gas selective condenser based on light-temperature coupling interaction real-time regulation, and belongs to the technical field of biomass regeneration, utilization and energy conversion equipment. BACKGROUND

[0002] The biomass pyrolysis liquefaction technology can convert agricultural and forestry waste, municipal waste, industrial organic waste and other waste biomass resources into liquid fuel bio-oil rich in acids, aldehydes, alcohols, phenols and other organic chemicals. The bio-oil can be used as a substitute for liquid fossil fuels for combustion and chemical industry. The fast pyrolysis liquefaction process principle is simple and easy to realize continuous feeding and large-scale production, which is one of the important means for developing biomass energy to participate in carbon dioxide emission reduction.

[0003] Although the bio-oil contains several high-value sugars and phenols, the bio-oil prepared by the traditional pyrolysis liquefaction process usually has the disadvantages of high moisture content, low calorific value and poor stability, which leads to low competitiveness of the bio-oil, and the application value is lower than that of traditional fossil fuels, which hinders the industrialization development of the pyrolysis liquefaction technology. Pyrolysis and condensation are two core processes of bio-oil preparation. The improvement of large-scale pyrolysis process requires higher technical methods, equipment and cost investment, and the technical barrier of condensation process optimization is relatively low, and the application effectiveness of the condensation process optimization is relatively higher in the pilot or commercial scale biomass pyrolysis liquefaction platform. The existing pilot or commercial pyrolysis gas condensation device has the following problems: first, the condensation adjustment is all based on the regulation method of pyrolysis gas temperature, and the control reference variable only involves the temperature state of the pyrolysis gas. In the actual biomass pyrolysis gas condensation process, the gas aerosol or oligomer components with unknown composition have no clear condensation point and other thermophysical properties, and it is difficult to effectively separate these components through pyrolysis gas temperature monitoring; secondly, the cooling method of each stage condenser in the current fractional condensation system is simple and rough, and the pyrolysis gas adopts a fixed heat exchange mode after the condenser is installed, and cannot be changed according to the composition demand of the pyrolysis gas; in addition, the structure size and regulation precision of the condenser are difficult to be simultaneously enhanced, and the condenser with large structure size usually cannot accurately adjust the cooling capacity, which leads to poor application effect of the fractional condensation technology in the large-scale bio-oil preparation process. SUMMARY

[0004] The application proposes a biomass pyrolysis gas selective condenser based on light-temperature coupling interaction real-time regulation, which aims to solve three main problems.

[0005] (1) Through multi-point light-temperature coupling real-time monitoring feedback, the fine regulation problem of the gas aerosol and oligomer components with unknown structure and performance in the biomass pyrolysis gas is solved.

[0006] (2) Design spray direct cooling and indirect cooling column interactive mechanism, to solve the problem of single rough condensation of biomass pyrolysis gas condenser.

[0007] (3) Put forward the unit type organization scheme of biomass pyrolysis gas condenser, solve the problem that the condensation capacity and regulation precision of condenser cannot be compatible in the process of large-scale bio-oil production.

[0008] The structure and principle of the biomass pyrolysis gas selective condenser based on light-temperature coupling interaction real-time regulation according to the present application are shown in Figure 1 The whole device is composed of multiple unit type composite condensing systems, light-temperature coupling real-time monitoring system, cooling capacity intelligent control system and bio-oil storage system. Among them: multiple unit type composite condensing systems constitute the main body of the selective condenser, which is used as the reaction place of biomass pyrolysis gas condensation; light-temperature coupling real-time monitoring system is configured before and after each unit type composite condensing system, which is used for analyzing and detecting the real-time temperature and light intensity of biomass pyrolysis gas; the light-temperature monitoring data are transmitted to the cooling capacity intelligent control system after system integration, and the control system is simultaneously linked with the direct condensation and indirect condensation control valves in the unit type composite condensing system, which is used for automatic regulation and control of the cooling capacity of the condensing device; the liquid product obtained by cooling the pyrolysis gas flows downward along the inner wall of the condenser, and is finally recovered and stored in the bio-oil storage system. The present application can automatically adjust the cooling capacity of the condenser according to the light-temperature coupling real-time monitoring data, realize fine biomass pyrolysis gas selective condensation and high-quality bio-oil preparation.

[0009] (1) Technical scheme of light-temperature coupling real-time monitoring dynamic regulation condensation

[0010] The technical scheme of light-temperature coupling real-time monitoring dynamic regulation condensation mainly relies on light-temperature coupling sensor, multi-channel data acquisition instrument and integrated PID controller. The light-temperature coupling sensor is arranged at the inlet and outlet of the condenser and the head and tail of each unit type composite condenser, the data detected by the sensor in real time are transmitted to the collector and simultaneously to the input end of the integrated PID controller, and the output end of the controller is linked with the spray liquid flow control valve and the circulating cooling liquid flow control valve.

[0011] The pyrolysis gas leaving the reactor usually has high temperature and low light intensity characteristics. With the development of condensation reaction, the temperature of pyrolysis gas gradually decreases and the light intensity gradually increases. For components with clear boiling points, the recovery of components can be judged according to the boiling point and real-time temperature; for components such as oligomers and aerosols with unknown boiling points and large molecular weights, the recovery of components can be judged according to the real-time light intensity. In the case of the strongest cooling capacity of the condenser, all spray devices and column tube cooling media in all unit type composite condensing equipment operate at maximum flow; in the case of the weakest condensing capacity of the condenser, all spray devices and column tube cooling media in all unit type composite condensing equipment operate at minimum flow or do not operate; when the condensing capacity is between the two, the flow or number of working spray devices and column tube cooling media in the unit type composite condensing equipment can be gradually reduced from the steam inlet to the outlet. When the condenser enhances the recovery of dewatered sugar or separates aerosol components, the working frequency of the spray device can be focused on improving; when the condenser enriches water or acetic acid and other light components with high content, the working frequency of the column tube cooling device can be focused on improving.

[0012] (2) Technical scheme of spray direct cooling and column tube indirect cooling synergistic interaction

[0013] The unit type composite condensing system is composed of 3 pairs of spray heads and 1 column tube heat exchanger from bottom to top. The flow valves of the 3 pairs of spray heads are independent of each other, and the cooling medium flow valve of the column tube heat exchanger is jointly regulated by the PID controller. The spray liquid can be selected from water, methanol, ethanol, alkanes or aqueous bio-oil, etc. The peristaltic pump and other devices are used to provide power for the spray liquid. The cooling medium of the column tube heat exchanger usually uses water, heat-conducting oil, low-temperature ethanol, etc. The centrifugal pump and other devices are used to provide power for the circulating medium.

[0014] In the large-scale bio-oil production process, the pyrolysis gas has high temperature and large flux, and multiple means are needed to strengthen heat exchange to improve the bio-oil yield. The steam inlet of the unit type composite condensing system is arranged at the bottom, and the outlet is arranged at the top, which ensures that the pyrolysis gas always moves upward against gravity during the condensation process, thereby improving the heat exchange frequency of the pyrolysis gas in the condensation field. At the front end of the composite condensing system, 3 pairs of spray heads are placed on both sides of the inner wall of the condenser to avoid uneven spraying and poor heat exchange effect, and to provide atomized cooling liquid from all directions and multiple points; at the rear end of the composite condensing system, a column tube type indirect heat exchanger is arranged, which is designed to have steam flowing inside and cooling water flowing outside. The pyrolysis gas enters from the bottom of the heat exchanger and flows out from the top, and the cooling water flows in from the top and flows out from the bottom. The flow directions of the pyrolysis gas and the cooling water always intersect in opposite directions, further improving the cooling effect. The flow of each spray head and the flow of the cooling water are independent of each other, and can be dynamically adjusted by the PID controller according to the real-time monitoring results of light and temperature.

[0015] (3) Unit type composition technical scheme of biomass pyrolysis gas selective condenser

[0016] The biomass pyrolysis gas selective condenser is composed of a plurality of unit composite condensing systems, a pyrolysis gas inlet, a pyrolysis gas outlet, a data collector, a PID controller, a corresponding number of transition linking intervals and light-temperature sensing probe heads. The pyrolysis gas inlet is linked to the bottom of the first unit composite condensing system through a flange, the top of the first unit composite condensing system is linked to the bottom of the first transition interval through a flange, the top of the first transition interval is linked to the bottom of the secondary unit composite condensing system through a flange, and so on until the top of the last unit composite condensing system is linked to the pyrolysis gas outlet through a flange. The inlet and outlet and all transition intervals are provided with light-temperature sensing probe heads, the detection data lines are concentrated and fed back to the data collector, the data collector is connected to the input end of the PID controller, and the output end of the controller is connected to the cooling medium flow valves.

[0017] In the actual selective condensation process for preparing multi-grade bio-oil, different power condensers are constructed according to the scale of biomass pyrolysis gas and the condensation capacity requirement. When the biomass feed quantity is less than 50 kg / h, the total number of condensers in the staged condensation system is set to be 3 at most, the first two stages of condensers are both provided with two sets of unit composite condensing systems, and the third stage of condenser can be provided with one set of unit composite condensing system. When the biomass feed quantity is higher than 50 kg / h and lower than 100 kg / h, four condensers can be configured, the first three stages of condensers are both provided with two sets of unit composite condensing systems, and the fourth stage of condenser is provided with one set of unit composite condensing system. When the feed quantity is between 100 kg / h and 150 kg / h, the total number of condensers should not be further increased to avoid insufficient space resources, four condensers are configured, the first two stages of condensers are both provided with three sets of unit composite condensing systems, and the last two stages of condensers are provided with two sets of unit composite condensing systems. When the feed quantity is between 150 kg / h and 200 kg / h, four condensers are configured, and the first four stages of condensers are all provided with three sets of unit composite condensing systems.

[0018] The test operation results of the present application are compared with the traditional biomass pyrolysis gas condensation technology, and the advantages and positive effects of the present application are mainly as follows:

[0019] Firstly, the multi-point light-temperature sensing coupling real-time monitoring feedback is used to finely control the aerosol and oligomer components in the biomass pyrolysis gas whose structure and performance are unknown, and the condensation capacity of the multi-stage condenser can be adjusted according to different target product requirements, so as to realize the separation of oligomers, the enrichment of phenolic compounds or the enrichment of light components, and the preparation of high-quality bio-oil.

[0020] Secondly, the PID controller is used to control the spray direct cooling and the tube indirect cooling to realize the cooperative interaction mechanism, the flow of the spray device and the tube cooling medium is accurately controlled, the use cost of the cooling medium is effectively reduced, and the heat and mass transfer efficiency is improved.

[0021] Third, the unit of biomass pyrolysis gas condenser scheme, to solve the problem of condenser condensation capacity and regulation precision cannot be compatible with the scale of bio-oil production process. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The structure diagram of the selective condenser for the light-temperature coupling interaction implementation control is shown in the figure.

[0023] Figure 2 The pyrolysis gas staged condensation system for 45kg / h biomass feed quantity is shown in the figure.

[0024] Figure 3 The pyrolysis gas staged condensation system for 75kg / h biomass feed quantity is shown in the figure.

[0025] Figure 4 The pyrolysis gas staged condensation system for 120kg / h biomass feed quantity is shown in the figure.

[0026] In the figure, ① pyrolysis gas inlet; ② temperature sensor; ③ light intensity sensor; ④ spray cooling head; ⑤ tube heat exchanger; ⑥ cooling water outlet; ⑦ cooling water inlet; ⑧ transition section; ⑨ pyrolysis gas outlet; ⑩ liquid product storage section. Data acquisition instrument; PID controller. DETAILED DESCRIPTION

[0027] The present application will be described in detail below with reference to the accompanying drawings and specific examples. However, the following examples are only for the purpose of explaining the present application, and the protection scope of the present application should include the entire content of the claims, and through the description of the following examples, those skilled in the art can fully realize the entire content of the claims of the present application.

[0028] The structural principle of Example 1 of the present application is shown in the figure. Figure 1As shown, the light-temperature coupling interactive implementation of the regulating selective condenser comprises two sets of unit composite condensing systems. The two sets of unit composite condensing systems are structured as follows: the two sets of unit composite condensing systems constitute a first-stage and a second-stage selective condenser, and the outer diameters thereof are kept consistent at 410 mm from bottom to top, the effective height of the composite condensing system is 800 mm, the transition interval is 200 mm, the vapor inlet and outlet height is 250 mm, and the effective height of the bottom liquid storage section is 300 mm. The light intensity sensor / temperature sensor is arranged at the inlet, outlet and transition interval. Alternatively, the light-temperature coupling interactive implementation of the regulating selective condenser structure further comprises a third-stage selective condenser arranged as a packed condenser, and the outer diameter thereof is uniformly 410 mm from top to bottom, and the effective total height is kept consistent with the previous two stages. Specifically, the two sets of unit composite condensing systems comprise a pyrolysis gas inlet ①, a temperature sensor ②, a light intensity sensor ③, a spray cooling head ④, a tube heat exchanger ⑤, a cooling water outlet ⑥, a cooling water inlet ⑦, a transition section ⑧, a pyrolysis gas outlet ⑨, a liquid product storage section ⑩, and a data acquisition instrument and a PID controller The condenser pyrolysis gas inlet ① section is arranged at the bottom end of the entire condenser, and is connected to the liquid product storage section ③ at the bottom end through a flange downward, and is connected to the first unit composite condensing system upward through a flange; the unit composite condensing system is welded by the lower 6 independently regulated spray cooling heads ④ and the upper 1 tube heat exchanger ⑤, wherein the tube heat exchanger has a cooling water outlet ⑥ and a cooling water inlet ⑦, which are connected to the external circulating water pipe through flanges, and the spray cooling head ④ is connected to the outside through a silica gel pipe; the upper end of the first unit composite condensing system is connected to the transition section ⑧ through a flange, and the upper end of the transition section is connected to the second unit composite condensing system through a flange; according to the requirements, a transition section can be further arranged at the upper end of the second unit composite system, and the upper end of the last unit composite condensing system is connected to the pyrolysis gas outlet ⑨ through a flange; the pyrolysis gas inlet ①, the transition section ⑧ and the pyrolysis gas outlet ⑨ are all provided with temperature sensors ② and light intensity sensors ③, and the monitoring results are input into the data acquisition instrument in real time The data are analyzed and output to the PID controller The output control conditions to the flow control devices of the spray cooling head 4, the cooling water outlet 6 and the cooling water inlet 7. The specific structure of the unit type composite condensing system is as follows: the pyrolysis gas inlet 1 section is arranged at the bottom end of the entire condenser, is connected to the liquid product storage section 10 through a flange at the lowest end downward, and is connected to the first unit type composite condensing system upward through a flange; the unit type composite condensing system is welded by the lower six independently regulated spray cooling heads 4 and the upper one tube heat exchanger 5, wherein the tube heat exchanger has a cooling water outlet 6 and a cooling water inlet 7, which are connected to the external circulating water pipe through flanges, and the spray cooling head 4 is connected to the outside through a silica gel pipe; the upper end of the first unit type composite condensing system is connected to the transition section 8 through a flange, and the upper end of the transition section is connected to the pyrolysis gas outlet 9 through a flange; the pyrolysis gas inlet 1, the transition section 8 and the pyrolysis gas outlet 9 are all provided with temperature sensors 2 and light intensity sensors 3, and the monitoring results are input into the data acquisition instrument in real time The data are analyzed and output control conditions are output to the PID controller The output control conditions to the flow control devices of the spray cooling head 4, the cooling water outlet 6 and the cooling water inlet 7, for example, the flow control devices are valves.

[0029] Through repeated experiments, it is determined that the initial electric signal return value of the light intensity sensor (referred to as light sensing) is set to 180, when the return value is 200-320, the feedback is that the pyrolysis gas is affected by the weakest condensing ability; when the return value is above 450, the feedback is that the pyrolysis gas is affected by the strongest cooling ability; when the return value is between 320-450, the feedback is that the condensing ability is between the two. The temperature sensor (referred to as temperature sensing) feedback value (℃) is above 300, the feedback is that the pyrolysis gas is affected by the weakest condensing ability; below 50, the feedback is that the pyrolysis gas is affected by the strongest cooling ability.

[0030] Using walnut shells as raw materials, the bio-oil was prepared by pyrolysis in the present embodiment, and the results obtained are as follows:

[0031] (1) As shown in Figure 2 , the pyrolysis gas grading condensing system with a biomass feed rate of 45 kg / h, the pyrolysis treatment capacity of the device is 45 kg / h when it is stably running, the total number of condensers in the grading condensing system is set to three, the first two condensers (i.e. the first condenser and the second condenser) are both configured with two sets of unit type composite condensing systems, and the third condenser is configured with one set of unit type composite condensing system. The pyrolysis gas outlet 9 of the first condenser is connected to the pyrolysis gas inlet 1 of the second condenser, the pyrolysis gas outlet 9 of the second condenser is connected to the pyrolysis gas inlet 1 of the third condenser, and the pyrolysis gas outlet 9 of the third condenser is discharged to the bio-oil storage system.

[0032] Stage 1: Inlet light sensor return value 450, temperature sensor return value 300; transition zone light sensor return value 400, temperature sensor return value 250; outlet light sensor return value 350, temperature sensor return value 200. Stage 2: Inlet light sensor return value 350, temperature sensor return value 200; transition zone light sensor return value 300, temperature sensor return value 150; outlet light sensor return value 250, temperature sensor return value 100. Stage 3: Inlet light sensor return value 250, temperature sensor return value 100; outlet light sensor return value 200, temperature sensor return value 50. Under these conditions, the total bio-oil yield is 50.3%, and the bio-oil yields of the three-stage condensers are 12.2%, 23%, and 15.1%, respectively. 80% of the oligomers and 50% of the phenolic compounds in the biomass pyrolysis gas are recovered in the first-stage condenser, and 50% of the phenolic compounds are recovered in the second-stage condenser, thus achieving the separation of detectable phenolic compounds from undetectable oligomers.

[0033] (2) Figure 3 As shown, the stable operation capacity of this device is 75 kg / h. The staged condensation system has a total of four condensers. The first three condensers (i.e., the first-stage condenser, the second-stage condenser, and the third-stage condenser) are each equipped with two sets of unit-type composite condensation systems, and the fourth-stage condenser is equipped with one set of unit-type composite condensation systems. The pyrolysis gas outlet ⑨ of the first-stage condenser is connected to the pyrolysis gas inlet ① of the second-stage condenser, the pyrolysis gas outlet ⑨ of the second-stage condenser is connected to the pyrolysis gas inlet ① of the third-stage condenser, the pyrolysis gas outlet of the third-stage condenser is connected to the pyrolysis gas inlet ① of the fourth-stage condenser, and the pyrolysis gas outlet ⑨ of the fourth-stage condenser discharges to the bio-oil storage system.

[0034] Stage 1: Inlet light sensor return value 550, temperature sensor return value 400; transition zone light sensor return value 530, temperature sensor return value 300; outlet light sensor return value 480, temperature sensor return value 270. Stage 2: Inlet light sensor return value 475, temperature sensor return value 270; transition zone light sensor return value 430, temperature sensor return value 220; outlet light sensor return value 400, temperature sensor return value 170. Stage 3: Inlet light sensor return value 396, temperature sensor return value 170; outlet light sensor return value 300, temperature sensor return value 150. Stage 4: Inlet light sensor return value 293, temperature sensor return value 70; outlet light sensor return value 200, temperature sensor return value 50. Under these conditions, the total bio-oil yield is 52.4%, and the bio-oil yields of the four-stage condensers are 18.8%, 23.2%, 10.4%, and 7.4%, respectively. Approximately 100% of the oligomers and 70% of the phenolic compounds in the biomass pyrolysis gas are recovered in the first-stage condenser, achieving complete separation of undetectable oligomers.

[0035] (3) Figure 4As shown, the pyrolysis processing capacity of the device when stably running is 120 kg / h, the number of total condensers in the staged condensation system is set to four, the first two condensers (i.e., the first condenser and the second condenser) are each configured with three sets of unit composite condensation systems, and the last two condensers (i.e., the third condenser and the fourth condenser) are configured with two sets of unit composite condensation systems. The pyrolysis gas outlet (9) of the first condenser is connected to the pyrolysis gas inlet (1) of the second condenser, the pyrolysis gas outlet (9) of the second condenser is connected to the pyrolysis gas inlet (1) of the third condenser, the pyrolysis gas outlet of the third condenser is connected to the pyrolysis gas inlet (1) of the fourth condenser, and the pyrolysis gas outlet (9) of the fourth condenser is discharged to the bio-oil storage system.

[0036] First stage: light sensing return value 680, temperature sensing return value 550 at the inlet, light sensing return value 610, temperature sensing return value 470 in the transition zone, and light sensing return value 540, temperature sensing return value 420 at the outlet; second stage: light sensing return value 536, temperature sensing return value 420 at the inlet, light sensing return value 480, temperature sensing return value 380 in the transition zone, and light sensing return value 430, temperature sensing return value 220 at the outlet; third stage: light sensing return value 427, temperature sensing return value 220 at the inlet, light sensing return value 350, temperature sensing return value 150 in the transition zone, and light sensing return value 306, temperature sensing return value 100 at the outlet; and fourth stage: light sensing return value 301, temperature sensing return value 100 at the inlet, and light sensing return value 200, temperature sensing return value 50 at the outlet. Under this condition, the total bio-oil yield is 53.2%, and the bio-oil yields of the four-stage condensers are 13.2%, 24.4%, 21.2%, and 4.6%, respectively. About 100% of the oligomers and 90% of the phenolic compounds in the biomass pyrolysis gas are recovered in the first-stage condenser, and almost all of the valuable light organic components are recovered in the second-stage condenser, achieving efficient separation of light components.

[0037] The part of the present application not described in detail belongs to the known technology of those skilled in the art. The above-described embodiments only describe the preferred embodiments of the present application, and the preferred embodiments do not describe all the details and limit the application to the specific embodiments described. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A selective condenser for biomass pyrolysis gas based on real-time control via photosensitive-temperature-sensitive coupling, characterized in that, The condenser includes multiple unit-type composite condensation systems, a real-time monitoring system coupled with photo- and temperature-sensing sensors, an intelligent cooling capacity control system, and a bio-oil storage system. The system comprises multiple unit-type composite condensation systems forming the main body of a selective condenser, serving as the reaction site for the condensation of biomass pyrolysis gas. Each unit-type composite condensation system is equipped with a photosensitive and temperature-sensing coupled real-time monitoring system before and after it, used to analyze and detect the real-time temperature and light intensity of the biomass pyrolysis gas, obtaining photosensitive and temperature-sensing monitoring data. This data is integrated by the system and transmitted to an intelligent cooling capacity control system. This control system also links to the direct and indirect condensation control valves in the unit-type composite condensation system, used to automatically regulate the cooling capacity of the condensation device. The liquid products obtained from the pyrolysis gas cooling flow downwards along the inner wall of the condenser and are ultimately recovered and stored in a bio-oil storage system. The unit-type composite condensation system consists of spray heads and tube heat exchangers from bottom to top. Multiple spray head flow valves are independent of each other and are jointly controlled by a PID controller along with the cooling medium flow valves of the tube heat exchangers. The spray liquid is water, methanol, ethanol, alkanes, or aqueous bio-oil liquid, powered by a peristaltic pump. The cooling medium of the tube heat exchanger is water, heat transfer oil, or ethanol liquid, powered by a centrifugal pump. The unit-type composite condensation system has its steam inlet located at the bottom and its outlet at the top, ensuring that the pyrolysis gas always moves against gravity from bottom to top during the condensation process, thereby increasing the heat exchange frequency of the pyrolysis gas in the condensation field. At the front end of the composite condensation system, multiple spray heads are placed on both sides of the inner wall of the condenser. At the rear end of the composite condensation system, a shell-and-tube indirect heat exchanger is installed, adopting a design where steam flows inside and cooling water flows outside. The pyrolysis gas enters from the bottom of the heat exchanger and flows out from the top, while the cooling water flows in from the top and flows out from the bottom, with the flow directions of the pyrolysis gas and cooling water always maintaining an opposite convergence. The flow rates of each spray head and the cooling water flow rate are independent of each other and are dynamically adjusted by a PID controller based on real-time monitoring results from light and temperature sensors. The condenser automatically adjusts its cooling capacity based on real-time monitoring data from photosensitive and temperature-sensitive coupling. The technical solution of real-time monitoring and dynamic adjustment of condensation by photo-temperature coupling relies on the coordinated control of photo-temperature coupling sensors, multi-channel data acquisition instruments, and integrated PID controllers. The photo-temperature coupling sensors are set at the inlet and outlet of the condenser pyrolysis gas and at both ends of each unit-type composite condenser. The data detected by the sensors in real time is transmitted to the acquisition instrument and simultaneously sent to the input of the integrated PID controller. The output of the controller is connected to the spray liquid flow control valve and the circulating coolant flow control valve.

2. The condenser according to claim 1, characterized in that, The biomass pyrolysis gas selective condenser consists of multiple unit-type composite condensation systems, a pyrolysis gas inlet, a pyrolysis gas outlet, a data acquisition unit, a PID controller, a corresponding number of transition connection sections, and photosensitive and temperature-sensitive detectors. The pyrolysis gas inlet is connected to the bottom of the first-stage unit-type composite condensation system via a flange. The top of the first unit-type composite condensation system is connected to the bottom of the first transition section via a flange. The top of the first transition section is connected to the bottom of the second-stage unit-type composite condensation system via a flange, and so on until the top of the final-stage unit-type composite condensation system is connected to the pyrolysis gas outlet via a flange. Photosensitive and temperature-sensitive detectors are installed at the pyrolysis gas inlet, pyrolysis gas outlet, and all transition sections. The detection data lines are centrally fed back to the data acquisition unit, which is also connected to the input of the PID controller. The output of the controller is connected to the flow valves of each cooling medium.

3. The condenser according to claim 1, characterized in that, In the selective condensation process for preparing multi-grade bio-oil, condensers with different efficiencies are constructed based on the scale of biomass pyrolysis gas and the required condensation capacity. When the biomass feed rate is less than 50 kg / h, the total number of condensers in the staged condensation system is set to a maximum of 3, with the first two stages each equipped with two sets of unit-type composite condensation systems, and the third stage equipped with one set of unit-type composite condensation systems. When the biomass feed rate is higher than 50 kg / h but lower than 100 kg / h, 4 condensers are configured, with the first three stages each equipped with two sets of unit-type composite condensation systems, and the fourth stage equipped with one set of unit-type composite condensation systems. When the feed rate is between 100 and 150 kg / h, 4 condensers are configured, with the first two stages each equipped with three sets of unit-type composite condensation systems, and the last two stages equipped with two sets of unit-type composite condensation systems. When the feed rate is between 150 and 200 kg / h, 4 condensers are configured, with the first four stages each equipped with three sets of unit-type composite condensation systems.

Images