Backflow control method, device, equipment and program product for carbon dioxide purification

Abstract

The invention relates to the field of carbon dioxide preparation, in particular to a backflow control method, device and equipment for carbon dioxide purification and a program product. The method comprises the following steps: determining components, inflow, working temperature and working air pressure of raw material gas in the carbon dioxide purification system, and determining constraint conditions of the purification rate after carbon dioxide purification; the working temperature, the working air pressure, the components, the inflow and the different backflow proportions are input into a backflow network model which is trained in advance, and purification rates and system energy consumption corresponding to the different backflow proportions are output through the backflow network model; according to the constraint condition of the purification rate, performing iterative optimization on the reflux proportion by taking the lowest system energy consumption as an optimization target, and determining the reflux proportion when the system energy consumption is the lowest under the condition that the constraint condition is met; carbon dioxide purification is carried out by controlling the opening degree of the backflow channel in the carbon dioxide purification system according to the backflow proportion, so that the system can meet the purification constraint, and the energy consumption of the system is effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of carbon dioxide preparation, and in particular to a reflux control method, device, equipment and program product for carbon dioxide purification. Background Art

[0002] With the booming development of modern industry, the impact of industry on the environment is becoming increasingly severe. Carbon dioxide, as a major industrial by-product, has huge emissions. If it is directly discharged into the atmosphere, it will cause the global greenhouse effect to continue to worsen. At the same time, carbon dioxide itself can have important application value in the fields of industry, agriculture, food, medicine, fine chemicals, etc. Therefore, the effective recycling of carbon dioxide has important economic value.

[0003] When recycling carbon dioxide, the carbon dioxide is usually separated from other gases by controlling the temperature and pressure according to the volatility difference of different components in the mixture, so as to obtain purified carbon dioxide. In the separation process, it is usually controlled according to the liquid level in the equipment. Due to the influence of various interference factors, more energy may be consumed in the purification process, which is not conducive to improving the purity of the purified carbon dioxide. Summary of the invention

[0004] In view of this, the embodiments of the present application provide a reflux control method, device, equipment and program product for carbon dioxide purification to solve the problem that the prior art requires more energy consumption and is not conducive to improving purity.

[0005] A first aspect of an embodiment of the present application provides a reflux control method for carbon dioxide purification, the reflux control method being applied to a carbon dioxide purification system, the carbon dioxide purification system comprising a condenser, a de-heavy tower and a de-light tower, the raw gas is de-heavy treated by passing through the de-heavy tower, the de-heavy treated raw gas enters the condenser for condensation treatment, the first part of the condensed liquid raw gas is refluxed to the de-heavy tower, the second part enters the de-light tower for de-light treatment, and purified carbon dioxide is obtained, the reflux control method comprising:

[0006] Determining the components of the raw gas in the carbon dioxide purification system, the inflow flow rate, the operating temperature and the operating pressure in the heavy removal tower and the light removal tower, and determining the constraints of the purification rate after the carbon dioxide purification;

[0007] The working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios are input into a pre-trained reflux network model, and the purification rate and system energy consumption corresponding to different reflux ratios are output through the reflux network model, wherein the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate out of the condenser;

[0008] According to the constraints of the purification rate, taking the minimum system energy consumption as the optimization goal, the reflux ratio is iteratively optimized to determine the reflux ratio when the system energy consumption is the lowest under the constraints;

[0009] The opening of the reflux channel in the carbon dioxide purification system is controlled according to the reflux ratio to purify carbon dioxide.

[0010] In combination with the first aspect, in a first possible implementation of the first aspect, according to the constraints of the purification rate, taking the minimum system energy consumption as the optimization goal, the reflux ratio is iteratively optimized to determine the reflux ratio when the system energy consumption is the lowest under the constraints, including:

[0011] Determine a reflux ratio range in which the purification rate is greater than a predetermined purity threshold value according to the purification rates and system energy consumption corresponding to different reflux ratios output by the reflux network model;

[0012] Determining system energy consumption change information corresponding to the reflux ratio according to the reflux ratio range;

[0013] The reflux ratio when the system energy consumption is the lowest is determined according to the system energy consumption change information.

[0014] In combination with the first aspect, in a second possible implementation manner of the first aspect, the carbon dioxide is purified by controlling the opening of the reflux channel in the carbon dioxide purification system according to the reflux ratio, and the method further includes:

[0015] According to the initial temperature and the initial gas pressure, combined with the working temperature and the working gas pressure, the intermediate temperature and the intermediate gas pressure of the de-weighting tower and / or the de-lighting tower are determined, and the system enters a gas-liquid equilibrium state according to the intermediate temperature and the intermediate gas pressure.

[0016] In combination with the second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, according to the initial temperature and the initial gas pressure, in combination with the working and the working gas pressure, the intermediate temperature and the intermediate gas pressure of the de-weighting tower and / or the de-lighting tower are determined, and according to the intermediate temperature and the intermediate gas pressure, the system enters a gas-liquid equilibrium state, including:

[0017] If the initial temperature is higher than the working temperature, then the intermediate temperature is determined to be lower than the working temperature; if the initial air pressure is lower than the working air pressure, then the intermediate air pressure is determined to be higher than the working air pressure;

[0018] The system is controlled to change from the initial temperature to the intermediate temperature and from the intermediate temperature to the working temperature at a predetermined temperature change rate, and to change from the initial air pressure to the intermediate air pressure and from the intermediate air pressure to the working air pressure at a predetermined air pressure change rate.

[0019] In combination with the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, controlling the system to change from the initial temperature to the intermediate temperature, and from the intermediate temperature to the operating temperature, at a predetermined temperature change rate, includes:

[0020] Controlling the system to change from the initial temperature to the intermediate temperature at a predetermined first temperature change rate, and to change from the intermediate temperature to the operating temperature at a predetermined second temperature change rate;

[0021] According to a predetermined pressure change rate, changing from the initial pressure to the intermediate pressure, and changing from the intermediate pressure to the working pressure, comprises:

[0022] changing from the initial air pressure to the intermediate air pressure according to a predetermined first air pressure change rate, and changing from the intermediate air pressure to the working air pressure according to a predetermined second air pressure change rate;

[0023] The first temperature change rate and the second temperature change rate are temperature change rates with different directions and magnitudes, and the first air pressure change rate and the second air pressure change rate are air pressure change rates with different directions and magnitudes.

[0024] In combination with the fourth possible implementation of the first aspect, in a fifth possible implementation of the first aspect, the absolute value of the first temperature change rate is greater than the absolute value of the second temperature change rate, and the absolute value of the first air pressure change rate is greater than the absolute value of the second air pressure change rate.

[0025] In combination with the first aspect, in a sixth possible implementation of the first aspect, before the working temperature, the working gas pressure, the components, the inflow flow rate, and different reflux ratios are input into a pre-trained reflux network model, and the purification rate and system energy consumption corresponding to different reflux ratios are output through the reflux network model, and the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate flowing out of the condenser, the method further includes:

[0026] Acquiring sample data, wherein the sample data includes sample operating temperature, sample operating pressure, sample components, sample inflow flow, sample reflux ratio, sample energy consumption, and sample purification rate;

[0027] The sample working temperature, the sample working pressure, the sample components, the sample inflow flow rate and the sample reflux ratio are input into a reflux network model, and a purification rate calculation value and a filling information energy consumption calculation value are calculated by the reflux network model;

[0028] A first deviation is determined according to the calculated value of the purification rate and the sample purification rate, a second deviation is determined according to the calculated value of the energy consumption and the sample energy consumption, and parameters of the reflux network model are adjusted according to the first deviation and the second deviation until the first deviation and the second deviation meet predetermined requirements, thereby obtaining a trained reflux network model.

[0029] A second aspect of an embodiment of the present application provides a reflux control device for carbon dioxide purification, the reflux control device being applied to a carbon dioxide purification system, the carbon dioxide purification system comprising a condenser, a de-weighting tower and a de-lighting tower, the raw gas is de-weighted by passing through the de-weighting tower, the de-weighted raw gas enters the condenser for condensation, the first part of the liquid raw gas after condensation is refluxed to the de-weighting tower, the second part enters the de-lighting tower for de-lighting, and purified carbon dioxide is obtained, the reflux control device comprising:

[0030] A data determination unit, used to determine the composition of the raw gas in the carbon dioxide purification system, the inflow flow rate, the working temperature and working pressure in the heavy removal tower and the light removal tower, and the constraint conditions of the purification rate after the carbon dioxide purification;

[0031] A calculation unit, used for inputting the working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios into a pre-trained reflux network model, and outputting the purification rate and system energy consumption corresponding to different reflux ratios through the reflux network model, wherein the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate flowing out of the condenser;

[0032] A reflux optimization unit, configured to iteratively optimize the reflux ratio according to the constraints of the purification rate and taking the minimum system energy consumption as the optimization goal, and determine the reflux ratio when the system energy consumption is the lowest under the constraints;

[0033] The purification unit is used to control the opening of the reflux channel in the carbon dioxide purification system according to the reflux ratio to purify the carbon dioxide.

[0034] A third aspect of an embodiment of the present application provides a carbon dioxide purification system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the carbon dioxide purification system implements the method described in any one of the first aspects.

[0035] A fourth aspect of the embodiments of the present application provides a computer program product, which, when executed on a computer, enables the computer to execute the method in the first aspect or its various implementations.

[0036] A fifth aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in any one of the first aspects are implemented.

[0037] The sixth aspect of the embodiment of the present application provides a chip for implementing the methods in each implementation of the first aspect. Specifically, the chip includes: a processor for calling and running a computer program from a memory, so that a device equipped with the chip executes the method in the first aspect or its implementation.

[0038] Compared with the prior art, the embodiments of the present application have the following beneficial effects: when the carbon dioxide is purified, the raw gas after the deheavy treatment enters the condenser for condensation treatment, the first part of the liquid raw gas after the condensation treatment is refluxed to the deheavy tower, and the second part is delightened to obtain the carbon dioxide after the warning, wherein, when performing reflux control, the determined working temperature, working gas pressure, components, injection flow rate and different reflux ratios are input into the trained reflux network model, and the purification rate and system energy consumption corresponding to different refluxes are output, and according to the constraints of the purification rate, the reflux ratio is iteratively optimized with the lowest system energy consumption as the optimization goal, and the reflux ratio is determined when the energy consumption is optimal under the constraints, and the carbon dioxide is purified according to the determined reflux ratio, so that the system can meet the purification constraints while effectively reducing the system energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 is a structural schematic diagram of a carbon dioxide purification system provided in an embodiment of the present application;

[0041] Figure 2 It is a schematic diagram of a process flow for realizing a reflux control method for purifying carbon dioxide provided in an embodiment of the present application;

[0042] Figure 3 It is a schematic diagram of an implementation flow of a method for training a reflux network model provided in an embodiment of the present application;

[0043] Figure 4 This is a schematic diagram of system initialization control provided by an embodiment of the present application;

[0044] Figure 5 is a schematic diagram of a reflux control device for carbon dioxide purification provided in an embodiment of the present application;

[0045] Figure 6 It is a schematic diagram of a carbon dioxide purification system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0047] In order to illustrate the technical solution described in this application, a specific embodiment is provided below for illustration.

[0048] The rapid development of modern industry has brought significant environmental challenges, especially the intensification of the global greenhouse effect caused by industrial carbon dioxide emissions. As an industrial byproduct, carbon dioxide emissions are huge. If they are directly discharged into the atmosphere, they will aggravate global warming. However, carbon dioxide has broad application potential in many fields, including industry, agriculture, food, medicine and fine chemicals. Therefore, achieving effective recovery and utilization of carbon dioxide will not only help alleviate environmental problems, but also have significant economic significance.

[0049] In the process of recycling carbon dioxide, the temperature and pressure are usually adjusted to separate carbon dioxide from other gases according to the volatility of different components to obtain high-purity carbon dioxide. This separation process often relies on the precise control of the liquid level in the equipment. Due to the existence of various external interferences, the purification process may consume more energy and affect the purification efficiency and purity of carbon dioxide. Therefore, optimizing purification technology, reducing energy consumption and improving purity are the keys to achieving efficient recycling of carbon dioxide.

[0050] Figure 1 A structural schematic diagram of a carbon dioxide purification system provided in an embodiment of the present application. As a brief illustration, the system includes a condenser, a de-heavy tower and a de-light tower. The raw gas is de-heavy treated by passing through the de-heavy tower, and the de-heavy treated raw gas enters the condenser for condensation treatment. The first part of the liquid raw gas after condensation treatment is refluxed to the de-heavy tower, and the second part enters the de-light tower for de-light treatment to obtain purified carbon dioxide.

[0051] The heavy components in the raw gas can be removed by removing the heavy components from the raw gas through the de-heavy tower. The de-heavy raw gas is transported to the condenser for condensation. In the condenser, the de-heavy raw gas is condensed by using an appropriate cooling medium and cooling temperature to convert it into a liquid state. The condensed liquid raw gas is divided into two parts. The first part is refluxed to the de-heavy tower as the reflux liquid of the de-heavy tower to improve the de-heavy effect, thereby improving the purification rate of the system. The second part of the condensed liquid raw gas is transported to the light-removing tower for further light-removal treatment. In the light-removing tower, according to the components of the liquid raw gas and the target carbon dioxide purity, appropriate operating conditions such as temperature, pressure and number of plates are selected to remove the light components from the liquid raw gas. Through the distillation of the light-removing tower, light components such as nitrogen and oxygen in the liquid raw gas are removed to obtain high-purity liquid carbon dioxide. The light component gas at the top of the light-removing tower is recovered or discharged, and the appropriate treatment method is selected according to environmental protection requirements and economic benefits. The purified high-purity liquid carbon dioxide is obtained from the bottom of the degassing tower and stored, transported or further processed according to downstream application requirements.

[0052] Figure 2 A schematic diagram of a carbon dioxide reflux control method provided in an embodiment of the present application, the method is based on Figure 1 The carbon dioxide purification system shown, the method comprising:

[0053] In S201, the components of the raw gas in the carbon dioxide purification system, the inflow flow rate, the operating temperature and the operating pressure in the heavy removal tower and the light removal tower, and the constraints of the purification rate after the carbon dioxide purification are determined.

[0054] The raw gas in the embodiments of the present application may include industrial exhaust gas, gas produced by biological processes, or gas directly captured from the atmosphere. Industrial exhaust gas includes gas produced by combustion of oil and coal mines, etc. Gas produced by biological processes includes gas produced by combustion of organisms or fermentation processes, etc.

[0055] In the carbon dioxide purification system, determining the composition of the raw gas, the inflow flow rate, the operating temperature and pressure in the de-heavy tower and the de-light tower, and the constraints on the purification rate of the carbon dioxide after purification can facilitate obtaining a system control method that meets the constraints under the determined operating conditions.

[0056] The components of raw gas usually include carbon dioxide, sulfur dioxide, nitrogen, oxygen, water vapor, etc. The content of different components will directly affect the efficiency of the purification process and the quality of the final product. For example, if the carbon dioxide content in the raw gas is low, more energy and equipment investment will be required to achieve the expected purification rate. Therefore, accurate determination of the components of raw gas is the basis for optimizing the purification process.

[0057] The inflow rate may refer to the flow rate of the raw gas flowing into the carbon dioxide purification system. The injection rate determines the processing capacity and efficiency of the system. By controlling the inflow rate, the operating conditions of the de-heavy tower and the de-light tower can be adjusted to achieve the best separation effect. For example, if the inflow rate is too large, it may lead to insufficient gas-liquid contact in the tower and reduce the separation efficiency; while if the inflow rate is too small, it will reduce the production capacity of the system and increase the energy consumption per unit product. Therefore, the appropriate inflow rate can be determined according to the design scale and target output of the system.

[0058] The working temperature and working gas pressure in the de-heavy tower and the de-light tower directly affect the thermodynamic equilibrium and kinetic characteristics of the separation process. Too high or too low working temperature will lead to a decrease in the separation effect, and changes in the working gas pressure will affect the distribution coefficient and mass transfer rate of the gas-liquid two phases. For example, in the de-heavy tower, the working temperature is usually maintained between -30°C and -50°C, and the working gas pressure is maintained between 1.5MPa and 2.0MPa to ensure that heavy components (such as water, sulfur dioxide, etc.) can be effectively separated from the raw gas. Similarly, in the de-light tower, the working temperature is usually controlled between -55°C and -65°C, and the working gas pressure is maintained between 0.1MPa and 0.3MPa to achieve efficient separation of light components (such as nitrogen, oxygen, etc.).

[0059] The constraint of carbon dioxide purification rate is a key indicator to measure the performance of the entire system. The purification rate is usually required to reach more than 99.99%, which places high demands on process control and equipment selection. For example, in order to achieve such a high purification rate, a reflux control method can be adopted through a heavy removal tower and a light removal tower. At the same time, the constraint of the purification rate will also affect the energy consumption and cost of the system. Too high a purification rate target may lead to a significant increase in energy consumption, while too low a purification rate cannot meet the requirements of downstream applications. Therefore, when setting the purification rate constraint, it is necessary to comprehensively consider factors such as technical feasibility, economic benefits and market demand to achieve the optimal design and operation of the system.

[0060] In a possible implementation, the working temperature and working pressure in the embodiment of the present application can be set to multiple sets of values, and the energy consumption under multiple sets of values ​​can be determined by the reflux control method in the embodiment of the present application. The corresponding relationship between different working temperatures and working pressures and energy consumption can be determined by fitting, thereby determining the optimal working temperature and working pressure. Among them, the working temperature and working pressure include the working temperature and working pressure in the de-weighting tower, condenser, de-lightening tower and other equipment.

[0061] In S202, the working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios are input into a pre-trained reflux network model, and the purification rate and system energy consumption corresponding to different reflux ratios are output through the reflux network model.

[0062] The reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate flowing out of the condenser.

[0063] In the carbon dioxide purification system, the de-heavy tower and the de-light tower are two key separation equipment. The de-heavy tower mainly removes heavy components in the raw gas, such as water, sulfur dioxide, etc., while the de-light tower mainly removes light components in the raw gas, such as nitrogen, methane, etc.

[0064] During the purification process, the working temperature and working pressure of the two towers have an important influence on the purification rate of carbon dioxide and the energy consumption of the system. Usually, the working temperature of the de-weighting tower is between -30℃ and -50℃, and the working pressure is between 1.5MPa and 2.5MPa; the working temperature of the de-lightening tower is between -50℃ and -70℃, and the working pressure is between 0.5MPa and 1.5MPa. Too high working temperature will lead to the ineffective separation of light and heavy components in the tower; too low working temperature will increase the energy consumption of the refrigeration system. Too high working pressure will increase the energy consumption of the compressor, while too low working pressure will affect the mass transfer and heat transfer effect of the gas-liquid two-phase in the tower. Therefore, the working temperature and working pressure of the de-weighting tower and the de-lightening tower can be optimized according to the composition and flow rate of the raw gas.

[0065] In addition to the working temperature and working pressure, the reflux ratio is also an important factor affecting the purification effect and energy consumption. The reflux ratio refers to the ratio of the liquid flow returning to the deweighting tower to the liquid flow out of the condenser. The larger the reflux ratio, the better the mass transfer effect in the tower and the higher the carbon dioxide purification rate; but at the same time, the reflux liquid needs to be re-evaporated, which will increase the energy consumption of the system.

[0066] Therefore, the embodiment of the present application needs to weigh the purification rate and energy consumption to find the best reflux ratio. In order to optimize the reflux ratio, process parameters such as working temperature, working pressure, components and inflow flow, as well as different reflux ratios, can be input into the pre-trained reflux network model. The model can be a neural network model, which establishes a nonlinear relationship between process parameters and purification rate and energy consumption through learning and training of a large amount of process data. For example, assuming that the components of the raw gas are: 90% carbon dioxide, 5% nitrogen, 3% methane, 1.5% water, 0.5% sulfur dioxide, and a flow rate of 100000Nm3 / h. The operating temperature of the de-heavy tower is -45°C and the pressure is 2MPa; the operating temperature of the de-light tower is -60°C and the pressure is 1MPa. Under this working condition, the reflux ratio is changed and the data is input into the reflux network model, and the carbon dioxide purification rate and system energy consumption corresponding to different reflux ratios can be obtained. As the reflux ratio increases, the carbon dioxide purification rate continues to increase, but the system energy consumption also increases.

[0067] Through the prediction of the reflux network model, the optimal reflux ratio can be quickly determined according to production needs, and the system energy consumption can be reduced as much as possible while meeting the purification rate requirements. In addition, the reflux network model can also cope with fluctuations in the composition and flow of the raw gas. When the composition of the raw gas changes, the new component data can be input into the model to predict the optimal reflux ratio under the new operating conditions. When the raw gas flow changes, the reflux ratio can also be adjusted to maintain the liquid-gas ratio in the tower to ensure the purification effect. This model-based control method can reduce the frequency of manual adjustments, improve the automation level and operational stability of the system, and minimize energy consumption while meeting product quality requirements. It is an important means to achieve efficient purification of carbon dioxide.

[0068] Energy consumption can include the energy consumption of major equipment such as condensers, de-heavy towers and de-light towers.

[0069] In a possible implementation, before using the reflux network model for calculation, the reflux network model may be trained in advance, such as Figure 3 As shown, the process includes:

[0070] In S301, sample data is obtained, where the sample data includes sample working temperature, sample working pressure, sample components, sample inflow flow, sample reflux ratio, sample energy consumption and sample purification rate.

[0071] The sample operating temperature and sample operating pressure in the embodiments of the present application may include multiple different operating temperatures and operating pressures. Under each set of operating temperatures and operating pressures, multiple different sample injection flow rates, sample reflux ratios, and sample energy consumptions may be included. Among them, the sample inflow flow rate, sample reflux ratio, sample purification rate, sample operating temperature, and sample operating pressure can be obtained through sensing equipment during the actual sampling process. The sample energy consumption can be determined by obtaining a unit of purified carbon dioxide, such as the electrical energy consumed by obtaining 1 ton of purified carbon dioxide. The sample components can be determined by gas chromatography or mass spectrometry after sampling, and the components may include the type of composition and the proportion of each type of gas.

[0072] In S302, the sample working temperature, the sample working pressure, the sample components, the sample inflow flow rate and the sample reflux ratio are input into a reflux network model, and the purification rate calculation value and the filling information energy consumption calculation value are calculated by the reflux network model.

[0073] The reflux network model in the embodiment of the present application may include, for example, a multilayer perceptron, a convolutional neural network model, a recurrent neural network model, etc. The input of the reflux network model includes the working temperature, the working air pressure, the sample components and the inflow flow rate, and the calculated output includes the calculated value of the purification rate and the calculated value of the energy consumption of the system.

[0074] In S303, a first deviation is determined based on the calculated value of the purification rate and the sample purification rate, a second deviation is determined based on the calculated value of the energy consumption and the sample energy consumption, and the parameters of the reflux network model are adjusted based on the first deviation and the second deviation until the first deviation and the second deviation meet predetermined requirements, thereby obtaining a trained reflux network model.

[0075] During the training process of the embodiment of the present application, the parameters of the reflux network model can be adjusted based on the deviation between the sample results and the calculation results of the model, including adjusting the number of hidden layers, learning rate, number of neurons, weight parameters, etc. of the reflux network model.

[0076] The calculation result may include a calculated value of the purification rate and a calculated value of the energy consumption. The first deviation may be determined based on the calculated value of the purification rate and the sample purification rate, and the second deviation may be determined based on the calculated value of the energy consumption and the sample energy consumption. The parameters of the reflux network model may be adjusted based on the magnitude of the first deviation and the second deviation until the first deviation and the second deviation meet predetermined requirements, such as being less than a predetermined deviation threshold.

[0077] In S203, according to the constraints of the purification rate and taking the minimum system energy consumption as the optimization goal, the reflux ratio is iteratively optimized to determine the reflux ratio when the system energy consumption is the lowest while satisfying the constraints.

[0078] According to the constraints of the purification rate, with the minimum system energy consumption as the optimization goal, the reflux ratio is iteratively optimized to determine the reflux ratio when the system energy consumption is the lowest under the constraints. This process can be achieved through the following steps: First, according to the purification rate and system energy consumption corresponding to the different reflux ratios output by the reflux network model, determine the reflux ratio corresponding to the purification rate meeting the predetermined requirements, such as greater than the predetermined purity threshold, and determine the change value of the reflux ratio when the purification rate is greater than the predetermined purity threshold according to the purity change curve. The range of the reflux ratio can be obtained by fitting multiple reflux ratios. After determining the range of the reflux ratio, multiple reflux ratios can be sampled within the range of the reflux ratio, and multiple system energy consumptions can be calculated by the reflux network model. The position of the lowest point of the system energy consumption can be determined by fitting and other methods. According to the corresponding relationship between the fitting curve of the system energy consumption and the fitting curve of the reflux ratio, the corresponding reflux ratio when the system energy consumption is the lowest can be determined.

[0079] Alternatively, after determining the reflux network model, the embodiment of the present application, under the premise of satisfying the carbon dioxide purification rate constraint condition, takes the minimum total system energy consumption as the optimization goal, and establishes a reflux ratio optimization model. The model takes the reflux ratio as the decision variable, the system energy consumption as the objective function, and introduces the purification rate as a constraint condition into the model. By solving the optimization model, the optimal reflux ratio corresponding to the lowest system energy consumption under different purification rate requirements can be obtained.

[0080] The embodiment of the present application can use an optimization algorithm to iteratively optimize and solve the reflux ratio for different purification rate constraints. Commonly used optimization algorithms include gradient descent method, genetic algorithm, particle swarm optimization algorithm, etc. In each iteration, the system energy consumption is calculated according to the current reflux ratio, and compared with the energy consumption value of the previous iteration to determine whether the convergence condition is reached. If convergence is not reached, the reflux ratio is updated according to the rules of the optimization algorithm, and the next round of iteration is performed until the optimal reflux ratio is found when the system energy consumption is the lowest under the constraint conditions.

[0081] In S204, the opening of the reflux channel in the carbon dioxide purification system is controlled according to the reflux ratio to purify carbon dioxide.

[0082] The embodiment of the present application applies the optimized optimal reflux ratio to the actual carbon dioxide purification system control. According to the optimal reflux ratio, the distribution ratio of the condenser outlet liquid is adjusted, and a part of it is refluxed to the de-heavy tower, and the other part enters the de-light tower for further purification. At the same time, the system operating parameters such as system temperature, system pressure, system flow, etc. are monitored to ensure that the system operates stably under the set working conditions, including working temperature, working pressure, and working flow.

[0083] By adjusting the reflux ratio, the operating status of the de-heavy tower and the de-light tower can be controlled, thereby optimizing the purification effect of carbon dioxide. Specifically, the adjustment of the reflux ratio is achieved by controlling the opening of the reflux channel. A control valve is installed on the reflux channel. By adjusting the opening of the control valve, the flow rate of the reflux liquid can be changed, and then the reflux ratio can be adjusted. When the reflux ratio increases, the amount of liquid raw gas refluxed to the de-heavy tower increases, the amount of liquid phase in the de-heavy tower increases, and the gas-liquid contact in the tower is more complete, which is beneficial to the removal of heavy components and the improvement of the purity of carbon dioxide; at the same time, the amount of liquid raw gas entering the de-light tower is reduced, and the load of the de-light tower is reduced, which is beneficial to the removal of light components and further improves the purity of carbon dioxide. In a possible implementation, the reflux ratio in the embodiment of the present application may also include the reflux ratio of the light-removing tower, including the ratio of the liquid raw gas in the light-removing tower to the heavy-removing tower or the light-removing tower and the liquid raw gas flowing out of the light-removing tower after the light-removing tower is light-removed, and by adjusting the reflux ratio of the light-removing tower, when the reflux ratio increases, the liquid raw gas refluxed to the heavy-removing tower or the light-removing tower increases, which is conducive to further heavy-removal and light-removal treatment, and improves the purity of carbon dioxide. When the reflux ratio includes two or more, the combined value range of each reflux ratio can be determined according to the purification rate, and the relationship between the change of each reflux ratio in the combined value range and the system energy consumption is determined, and the combination of reflux ratios corresponding to the optimal energy consumption is determined based on the change relationship.

[0084] When the reflux ratio decreases, the amount of liquid raw gas refluxed to the de-heavy tower decreases, the amount of liquid raw gas entering the de-light tower increases, and the load of the de-light tower increases, which is beneficial to improving the recovery efficiency of carbon dioxide, but may reduce the purity of carbon dioxide.

[0085] In the embodiment of the present application, the appropriate reflux ratio can be determined according to the parameters such as the composition, flow rate, temperature and pressure of the de-heavy tower and the de-light tower of the raw gas, and the requirements of the carbon dioxide purification rate. For example, when the content of heavy components in the raw gas is high, the reflux ratio can be appropriately increased to enhance the de-heavy effect; when the content of light components in the raw gas is high, the reflux ratio can be appropriately reduced to enhance the de-light effect. Under normal circumstances, the value range of the reflux ratio is 20% to 80%, and the specific value needs to be optimized and adjusted according to the actual working conditions. In the control process of the reflux ratio, the following points should also be noted: First, the adjustment of the reflux ratio should be coordinated with the temperature and pressure control of the de-heavy tower and the de-light tower to optimize the equilibrium state of the gas-liquid two phases in the tower; second, the adjustment of the reflux ratio should be carried out smoothly to avoid large fluctuations, so as not to impact the stable operation of the system; third, the control valve on the reflux channel should be regularly inspected and maintained to ensure its sensitivity and reliability to ensure the accuracy of the reflux ratio control. By properly controlling the reflux ratio, the energy consumption and cost of the carbon dioxide recovery system can be improved while ensuring the carbon dioxide purification rate, thus achieving the optimal operation of the carbon dioxide purification system. This is of great significance for reducing greenhouse gas emissions and promoting carbon capture and utilization.

[0086] In an embodiment of the present application, in order to quickly enable the carbon dioxide purification system to enter a gas-liquid equilibrium state, the embodiment of the present application may also include optimization control to improve the purification efficiency of the system. The intermediate state for optimizing the purification efficiency, including medium temperature and intermediate pressure, can be determined based on the initial state of the system, including initial temperature and initial pressure, combined with the set working state, including working temperature and working pressure. The state changes of the system are controlled according to the initial state, working state and intermediate state, so that the system can enter a gas-liquid equilibrium state faster.

[0087] In possible implementations, such as Figure 4 In the system initialization control diagram shown, if the value of the initial state is less than the value of the working state, the value of the intermediate state is determined to be greater than the value of the working state, so that the system is gradually adjusted from the initial state to the intermediate state, and then to the working state. If the value of the initial state is higher than the value of the working state, the value of the intermediate state is determined to be less than the value of the working state, so that the system is gradually adjusted from the initial state to the intermediate state, and then to the working state.

[0088] The absolute value of a first change speed V1 of the system state being adjusted from the initial state to the working state may be greater than the absolute value of a second change speed V2 of the system state being adjusted from the intermediate state to the working state.

[0089] For example, if the initial temperature is higher than the working temperature, it can be determined that the intermediate temperature is lower than the working temperature, and if the initial air pressure is lower than the working air pressure, it can be determined that the intermediate air pressure is higher than the working air pressure. A first time length for adjusting the initial state to the intermediate state and a second time length for adjusting the intermediate state to the working state can be set to gradually adjust the system state.

[0090] For example, the control system can be controlled from the initial temperature to the intermediate temperature according to the first temperature change rate, from the intermediate temperature to the working temperature according to the second temperature change rate, from the initial pressure to the intermediate pressure according to the first air pressure change rate, and from the intermediate pressure to the working pressure according to the second air pressure change rate. The first temperature change rate and the second temperature change rate are temperature change rates with different directions and magnitudes, and the first air pressure change rate and the second air pressure change rate are air pressure change rates with different directions and magnitudes. In order to quickly adapt to the gas-liquid equilibrium state under the working state, the absolute value of the first temperature change rate can be set to be greater than the absolute value of the second temperature change rate, and the absolute value of the first air pressure change rate can be set to be greater than the absolute value of the second air pressure change rate.

[0091] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0092] Figure 5 A schematic diagram of a reflux control device for carbon dioxide purification provided in an embodiment of the present application, wherein the reflux control device is applied to a carbon dioxide purification system, wherein the carbon dioxide purification system comprises a condenser, a de-weighting tower and a de-lighting tower, wherein the raw gas is de-weighted by passing through the de-weighting tower, and the de-weighted raw gas enters the condenser for condensation, wherein the first part of the liquid raw gas after condensation is refluxed to the de-weighting tower, and the second part enters the de-lighting tower for de-lighting to obtain purified carbon dioxide, wherein the reflux control device comprises:

[0093] A data determination unit, used to determine the composition of the raw gas in the carbon dioxide purification system, the inflow flow rate, the working temperature and working pressure in the heavy removal tower and the light removal tower, and the constraint conditions of the purification rate after the carbon dioxide purification;

[0094] A calculation unit, used for inputting the working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios into a pre-trained reflux network model, and outputting the purification rate and system energy consumption corresponding to different reflux ratios through the reflux network model, wherein the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate flowing out of the condenser;

[0095] A reflux optimization unit, configured to iteratively optimize the reflux ratio according to the constraints of the purification rate and taking the minimum system energy consumption as the optimization goal, and determine the reflux ratio when the system energy consumption is the lowest under the constraints;

[0096] The purification unit is used to control the opening of the reflux channel in the carbon dioxide purification system according to the reflux ratio to purify the carbon dioxide.

[0097] Figure 5 The reflux control device for carbon dioxide purification shown in FIG. Figure 2 The reflux control method for carbon dioxide purification shown corresponds to this.

[0098] Figure 6 Schematic diagram of a carbon dioxide purification system provided in an embodiment of the present application. Figure 6 As shown, the carbon dioxide purification system 6 of this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60, such as a reflux control program for carbon dioxide purification. When the processor 60 executes the computer program 62, the steps in the above-mentioned reflux control method embodiments for carbon dioxide purification are implemented. Alternatively, when the processor 60 executes the computer program 62, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0099] Exemplarily, the computer program 62 may be divided into one or more modules / units, which are stored in the memory 61 and executed by the processor 60 to complete the present application. The one or more modules / units may be a series of computer program instruction segments capable of completing specific functions, which are used to describe the execution process of the computer program 62 in the carbon dioxide purification system 6.

[0100] The carbon dioxide purification system may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will appreciate that Figure 6 It is only an example of a carbon dioxide purification system 6 and does not constitute a limitation of the carbon dioxide purification system 6. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the carbon dioxide purification system may also include input and output devices, network access devices, buses, etc.

[0101] The processor 60 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0102] The memory 61 may be an internal storage unit of the carbon dioxide purification system 6, such as a hard disk or memory of the carbon dioxide purification system 6. The memory 61 may also be an external storage device of the carbon dioxide purification system 6, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the carbon dioxide purification system 6. Further, the memory 61 may also include both an internal storage unit and an external storage device of the carbon dioxide purification system 6. The memory 61 is used to store the computer program and other programs and data required by the carbon dioxide purification system. The memory 61 may also be used to temporarily store data that has been output or is to be output.

[0103] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0104] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0105] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0106] In the embodiments provided in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0107] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0109] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the process in the above-mentioned embodiment method, and can also be completed by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0110] In addition, an embodiment of the present application also provides a computer program product, which, when executed on a computer, enables the computer to execute the methods in the above-mentioned implementation modes.

[0111] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A reflux control method for carbon dioxide purification, characterized in that: The reflux control method is applied to a carbon dioxide purification system, which includes a condenser, a de-heavy tower and a de-light tower. The raw gas is de-heavy treated by passing through the de-heavy tower. The de-heavy treated raw gas enters the condenser for condensation treatment. The first part of the condensed liquid raw gas is refluxed to the de-heavy tower, and the second part enters the de-light tower for de-light treatment to obtain purified carbon dioxide. The reflux control method includes: Determining the components of the raw gas in the carbon dioxide purification system, the inflow flow rate, the operating temperature and the operating pressure in the heavy removal tower and the light removal tower, and determining the constraints of the purification rate after the carbon dioxide purification; The working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios are input into a pre-trained reflux network model, and the purification rate and system energy consumption corresponding to different reflux ratios are output through the reflux network model, wherein the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate out of the condenser; According to the constraints of the purification rate, taking the minimum system energy consumption as the optimization goal, the reflux ratio is iteratively optimized to determine the reflux ratio when the system energy consumption is the lowest under the constraints; The carbon dioxide is purified by controlling the opening of the reflux channel in the carbon dioxide purification system according to the reflux ratio.

2. The method according to claim 1, characterized in that According to the constraints of the purification rate, taking the minimum system energy consumption as the optimization goal, the reflux ratio is iteratively optimized to determine the reflux ratio when the system energy consumption is the lowest under the constraints, including: Determine a reflux ratio range in which the purification rate is greater than a predetermined purity threshold value according to the purification rates and system energy consumption corresponding to different reflux ratios output by the reflux network model; Determining system energy consumption change information corresponding to the reflux ratio according to the reflux ratio range; The reflux ratio when the system energy consumption is the lowest is determined according to the system energy consumption change information.

3. The method according to claim 1, characterized in that The carbon dioxide is purified by controlling the opening of the reflux channel in the carbon dioxide purification system according to the reflux ratio, and the method further includes: According to the initial temperature and the initial gas pressure, combined with the working temperature and the working gas pressure, the intermediate temperature and the intermediate gas pressure of the de-weighting tower and / or the de-lighting tower are determined, and the system enters a gas-liquid equilibrium state according to the intermediate temperature and the intermediate gas pressure.

4. The method according to claim 3, characterized in that According to the initial temperature and the initial pressure, in combination with the working pressure and the working pressure, the intermediate temperature and the intermediate pressure of the de-weighting tower and / or the de-lighting tower are determined, and the control system enters a gas-liquid equilibrium state according to the intermediate temperature and the intermediate pressure, including: If the initial temperature is higher than the working temperature, then the intermediate temperature is determined to be lower than the working temperature; if the initial air pressure is lower than the working air pressure, then the intermediate air pressure is determined to be higher than the working air pressure; The system is controlled to change from the initial temperature to the intermediate temperature and from the intermediate temperature to the working temperature at a predetermined temperature change rate, and to change from the initial air pressure to the intermediate air pressure and from the intermediate air pressure to the working air pressure at a predetermined air pressure change rate.

5. The method according to claim 4, characterized in that Controlling the system to change from the initial temperature to the intermediate temperature, and from the intermediate temperature to the operating temperature at a predetermined temperature change rate, comprises: Controlling the system to change from the initial temperature to the intermediate temperature at a predetermined first temperature change rate, and to change from the intermediate temperature to the operating temperature at a predetermined second temperature change rate; According to a predetermined pressure change rate, changing from the initial pressure to the intermediate pressure, and changing from the intermediate pressure to the working pressure, comprises: changing from the initial air pressure to the intermediate air pressure according to a predetermined first air pressure change rate, and changing from the intermediate air pressure to the working air pressure according to a predetermined second air pressure change rate; The first temperature change rate and the second temperature change rate are temperature change rates with different directions and magnitudes, and the first air pressure change rate and the second air pressure change rate are air pressure change rates with different directions and magnitudes.

6. The method according to claim 5, characterized in that An absolute value of the first temperature change rate is greater than an absolute value of the second temperature change rate, and an absolute value of the first air pressure change rate is greater than an absolute value of the second air pressure change rate.

7. The method according to claim 1, characterized in that Before the working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios are input into a pre-trained reflux network model, and the purification rate and system energy consumption corresponding to different reflux ratios are output through the reflux network model, wherein the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate out of the condenser, the method further comprises: Acquiring sample data, wherein the sample data includes sample operating temperature, sample operating pressure, sample components, sample inflow flow, sample reflux ratio, sample energy consumption, and sample purification rate; The sample working temperature, the sample working pressure, the sample components, the sample inflow flow rate and the sample reflux ratio are input into a reflux network model, and a purification rate calculation value and a filling information energy consumption calculation value are calculated by the reflux network model; A first deviation is determined according to the calculated value of the purification rate and the sample purification rate, a second deviation is determined according to the calculated value of the energy consumption and the sample energy consumption, and parameters of the reflux network model are adjusted according to the first deviation and the second deviation until the first deviation and the second deviation meet predetermined requirements, thereby obtaining a trained reflux network model.

8. A reflux control device for carbon dioxide purification, characterized in that: The reflux control device is applied to a carbon dioxide purification system, which includes a condenser, a de-heavy tower and a de-light tower. The raw gas is de-heavy treated by passing through the de-heavy tower. The de-heavy treated raw gas enters the condenser for condensation treatment. The first part of the condensed liquid raw gas is refluxed to the de-heavy tower, and the second part enters the de-light tower for de-light treatment to obtain purified carbon dioxide. The reflux control device includes: A data determination unit, used to determine the composition of the raw gas in the carbon dioxide purification system, the inflow flow rate, the working temperature and working pressure in the heavy removal tower and the light removal tower, and the constraint conditions of the purification rate after the carbon dioxide purification; A calculation unit, used for inputting the working temperature, the working gas pressure, the components, the inflow flow rate and different reflux ratios into a pre-trained reflux network model, and outputting the purification rate and system energy consumption corresponding to different reflux ratios through the reflux network model, wherein the reflux ratio is the ratio of the flow rate of the condenser refluxed to the deweighting tower to the flow rate flowing out of the condenser; A reflux optimization unit, configured to iteratively optimize the reflux ratio according to the constraints of the purification rate and taking the minimum system energy consumption as the optimization goal, and determine the reflux ratio when the system energy consumption is the lowest under the constraints; The purification unit is used to control the opening of the reflux channel in the carbon dioxide purification system according to the reflux ratio to purify the carbon dioxide.

9. A carbon dioxide purification system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the carbon dioxide purification system is caused to implement the method according to any one of claims 1 to 7.

10. A computer program product comprising computer program instructions, characterized in that When the computer program is executed, the method according to any one of claims 1 to 7 is performed.

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