Method and device for solving chemical equilibrium of amine acid system in natural gas purification plant

Abstract

The present invention discloses a method and device for solving the chemical equilibrium of an amine acid system in a natural gas purification plant. The method comprises: obtaining multiple reaction formulas of the chemical equilibrium of a mathematical model of an amine acid system in a natural gas purification plant; determining the current concentration of each ion involved in each reaction formula as the initial concentration; determining the current value of the equilibrium constant in each reaction formula as the initial value; for each reaction formula, iteratively performing the following steps until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and outputting the latest concentration of each ion: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, using a reaction amount solving formula to solve the reaction amount of the reaction formula; calculating the latest concentration of each ion according to the reaction amount and the current concentration of each ion; updating the current concentration of each ion and the current value of the equilibrium parameter. The present invention can improve the stability and efficiency of solving the chemical equilibrium of the amine acid system.

Description

Technical Field

[0001] The invention relates to the technical field of amine acid system analysis in a natural gas purification plant, and in particular to a method and a device for solving the chemical balance of the amine acid system in a natural gas purification plant. Background Art

[0002] This section is intended to provide a background or context to the embodiments of the invention recited in the claims. No admission is made that the description herein is prior art by inclusion in this section.

[0003] The natural gas purification plant connects the production of natural gas fields and the transportation of long-distance pipelines, and undertakes the important tasks of natural gas desulfurization, decarbonization, dehydration and sulfur recovery. The acid gas removed by the deacidification unit of the natural gas purification plant mainly contains hydrogen sulfide and carbon dioxide. The two main equipment units used in the deacidification process of the natural gas purification plant are the absorption tower and the regeneration tower. The absorption of acid gas by amine liquid is carried out in the absorption tower, and the amine liquid that has absorbed the acid gas is regenerated in the regeneration tower. The absorption and regeneration process of hydrogen sulfide by amine liquid is a phase equilibrium problem involving multi-stage chemical equilibrium. In the early design of the natural gas purification plant and the later operation optimization stage, it is necessary to clarify the absorption amount of hydrogen sulfide and carbon dioxide by amine liquid. Experiments are the main source of data in the early stage, but there are great limitations in the experimental determination of the solubility of acid gas in amine liquid. For example, affected by the accuracy of experimental instruments and the subjective factors of experimenters, there are usually large deviations in experimental results, and the results measured by different research groups under the same temperature and pressure conditions often have large deviations. In order to obtain reliable data, a large number of repeated experiments are usually required for statistical analysis. On the other hand, experimental data under extreme conditions cannot be carried out due to the limitation of the instrument test range. For example, for some data under ultra-high pressure, ultra-high temperature, ultra-low temperature and zero pressure conditions, due to the limitation of experimental instruments, they cannot be obtained through experiments and can only be obtained through the extension of theoretical models. Another important limitation of obtaining data through experimental methods is that it is impossible to obtain extension data, and experimental data can only obtain limited experimental data points. For a specific amine liquid system, it takes a lot of manpower and material resources to carry out carbon dioxide and hydrogen sulfide solubility experiments under different temperatures, pressures and amine liquid concentrations. In the design and operation optimization stage of a natural gas purification plant, continuous data of amine liquids of different concentrations under different temperature and pressure conditions are usually required. It is almost impossible to obtain continuous hydrogen sulfide and carbon dioxide solubility data through experiments. In order to obtain continuous data of amine liquid absorbing acid gas, a mathematical model of the amine acid system must be established. Determining the key parameters of the mathematical model through less experimental data, so as to obtain an ideal mathematical model of the amine acid system is the main research direction of current scholars. Establishing a complete mathematical model of the amino acid system can obtain extended data that cannot be carried out in experiments, can meet the continuous data under different temperature and pressure conditions required by the project, and can provide automatic, efficient and fast calculation results for the operation optimization of the natural gas purification plant.

[0004] The mathematical model of the amine acid system includes the chemical balance of the absorption process of hydrogen sulfide and carbon dioxide by amine liquid and the gas-liquid phase balance of a certain concentration of amine liquid under certain conditions (temperature, pressure). The chemical balance of the amine acid system seriously affects all aspects of the natural gas deacidification process in the field of oil and gas field surface engineering, such as the absorption process of natural gas in the absorption tower, the pressure reduction process in the pressure reducing valve, the flash process in the flash tank, the heat exchange process in the heat exchanger, the regeneration process in the regeneration tower, etc. Accurate and efficient chemical balance calculation is a necessary condition for the establishment of the mathematical model of the amine acid system.

[0005] Currently, most algorithms for solving chemical equilibrium use the Newton-Raphson method and the polynomial method. By constructing a multivariate nonlinear equation system and solving it using the Newton-Raphson method, this method is heavily dependent on the stability of the initial value. The polynomial method is mainly aimed at simple monoamine and monoacid systems and cannot cope with complex amino acid systems.

[0006] Therefore, there is currently a lack of a method for solving the chemical equilibrium of an amino acid system to address the problems of instability and low efficiency in solving the chemical equilibrium. Summary of the invention

[0007] The embodiment of the present invention provides a method for solving the chemical equilibrium of an amine acid system in a natural gas purification plant, which is used to improve the stability and efficiency of solving the chemical equilibrium of the amine acid system. The method comprises:

[0008] Obtain multiple reaction equations of chemical equilibrium of the mathematical model of the amine acid system of the natural gas purification plant;

[0009] Determine the current concentration of each ion involved in each reaction equation as the initial concentration;

[0010] Determine the current value of the equilibrium constant in each reaction equation as the initial value;

[0011] For each reaction formula, the following steps are iteratively performed until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and the latest concentration of each ion involved in the reaction formula is output:

[0012] Based on the current concentration of each ion involved in the reaction equation and the current value of the equilibrium constant, the reaction amount of the reaction equation is solved using a reaction amount solution formula;

[0013] Calculate the latest concentration of each ion based on the reaction amount and the current concentration of each ion;

[0014] Update the current concentration of each ion and the current values ​​of the equilibrium parameters.

[0015] The embodiment of the present invention further provides a device for solving the chemical balance of an amine acid system in a natural gas purification plant, which is used to improve the stability and efficiency of solving the chemical balance of the amine acid system. The device comprises:

[0016] A reaction formula acquisition module is used to obtain multiple reaction formulas of chemical equilibrium of the mathematical model of the amine acid system of the natural gas purification plant;

[0017] An ion concentration determination module, used to determine the current concentration of each ion involved in each reaction formula as the initial concentration;

[0018] An equilibrium constant determination module, used to determine the current value of the equilibrium constant in each reaction formula as an initial value;

[0019] The iterative module is used to iteratively execute the following steps for each reaction formula until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and output the latest concentration of each ion involved in the reaction formula: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, the reaction amount of the reaction formula is solved using a reaction amount solution formula; based on the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated; and the current concentration of each ion and the current value of the equilibrium parameter are updated.

[0020] An embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for solving the chemical equilibrium of the amine acid system in the natural gas purification plant when executing the computer program.

[0021] An embodiment of the present invention further 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 above-mentioned method for solving the chemical equilibrium of the amine-acid system of a natural gas purification plant is implemented.

[0022] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for solving the chemical equilibrium of the amine-acid system in the natural gas purification plant is implemented.

[0023] In an embodiment of the present invention, multiple reaction formulas of chemical equilibrium of a mathematical model of an amino acid system in a natural gas purification plant are obtained; the current concentration of each ion involved in each reaction formula is determined as an initial concentration; the current value of the equilibrium constant in each reaction formula is determined as an initial value; for each reaction formula, the following steps are iteratively performed until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and the latest concentration of each ion involved in the reaction formula is output: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, the reaction amount of the reaction formula is solved using a reaction amount solution formula; based on the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated; and the current concentration of each ion and the current value of the equilibrium parameter are updated. Compared with the technical solutions of the prior art that use the Newton-Raphson method and the polynomial method to solve chemical equilibrium, the latest concentration of each ion is updated by iteratively using the reaction amount solution formula to solve the reaction amount of each reaction equation until the difference between the latest concentration of each ion involved in the reaction equation and the current concentration is within a preset range, that is, the equilibrium of the ion concentration is achieved. Since a given initial value is not required, the solution process is stable, and it can be used for complex multi-reaction equations with high solution efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0025] Figure 1 This is a flow chart of a method for solving the chemical equilibrium of an amine acid system in a natural gas purification plant according to an embodiment of the present invention;

[0026] Figure 2 A flow chart of a solution formula for determining the reaction amount in an embodiment of the present invention;

[0027] Figure 3 CO in the solution in the implementation of the present invention 2 and H + Convergence curve comparison chart of ;

[0028] Figure 4 CO in the embodiment of the present invention 2 Comparison of equilibrium solubility in MDEA solution;

[0029] Figure 5 Schematic diagram of a chemical equilibrium solving device for an amine acid system in a natural gas purification plant according to an embodiment of the present invention Figure 1 ;

[0030] Figure 6 Schematic diagram of a chemical equilibrium solving device for an amine acid system in a natural gas purification plant according to an embodiment of the present invention Figure 2 ;

[0031] Figure 7 Schematic diagram of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0033] The acid gas removed by the deacidification unit of the natural gas purification plant mainly contains hydrogen sulfide and carbon dioxide. The solvent used is usually N-Methyldiethanolamine (MDEA) and Monoethanolamine (MEA) solution. MDEA and MEA solutions react when absorbing hydrogen sulfide and carbon dioxide. In one embodiment, the chemical equilibrium reaction formula of the mathematical model of the amine-acid system of the natural gas purification plant includes:

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042] Each reaction is bidirectional.

[0043] The equilibrium constant expression of the reaction is as follows:

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] Where: K i is the chemical equilibrium constant; x i is the molar concentration of the ion, mol / L; γ i is the activity coefficient of the solvent; is the asymmetric activity coefficient of the solvent.

[0053] When using the Newton-Raphson method to solve, in addition to the above chemical equilibrium equation, the following material conservation equation and charge conservation equation should also be included.

[0054] Material balance equation for carbon dioxide:

[0055]

[0056] Material balance equation for hydrogen sulfide:

[0057]

[0058] Material balance equation for amine solution:

[0059]

[0060]

[0061] Charge balance:

[0062]

[0063] Where: α i is the acid gas load, mol CO 2 (H 2 S) / mol amine; m i is the mass molar concentration, mol / kg; M W is the molar mass of water, g / mol; n T is the total number of moles of ions (or molecules) in the solution, mol.

[0064]

[0065]

[0066]

[0067] The multivariate chemical equilibrium equation is transformed into the form of F(x) = 0, as shown in formula (22). For the multivariate nonlinear equation system F(x) = 0, the Newton-Raphson method first derives the Jacobi matrix of F(x): When the Jacobi matrix When reversible, the iterative formula (24) can be used for iterative solution.

[0068] When using the Newton-Raphson method to solve, take the absorption of CO2 by MDEA solution as an example, the multivariate nonlinear equation group is as shown in formula (22). Formula (24) is used for iterative solution. In the case of the solution, the concentration of MDEA is 4.28 mol / L, the temperature is 393.15 K, and the solution results under different pressure conditions are shown in Table 1. When the pressure is 0.143-0.479 kPa, negative numbers appear in the solution results when the Newton-Raphson method is used to solve, indicating that during the iteration process, the Newton-Raphson method converges to a solution without physical meaning. The chemical equilibrium problem of the amino acid system is a multivariate nonlinear problem. Theoretically, there are multiple solutions. According to the specific physical meaning, only one solution has physical meaning. When using the Newton-Raphson method to solve, an initial value must be given first. Different initial values ​​have a great influence on the convergence of the Newton-Raphson method. This is the main reason why the Newton-Raphson method obtains solutions without physical meaning.

[0069] Table 1 Newton-Raphson method solution results

[0070]

[0071] When solving with the polynomial method, for the amine acid system of monoamine liquid and monoacid gas, the chemical equilibrium equations are relatively few. By eliminating the variables of the multivariate nonlinear equations, they are organized into a polynomial with only one unknown variable. After the solution of the polynomial is obtained, the concentration of each ion is calculated separately. For the amine liquid-acid gas reaction system of the deacidification unit of the natural gas purification plant, the equations can usually be organized into a polynomial of hydronium ions, with MDEA solution absorbing CO 2 For example, the polynomial after arrangement is as shown in formula (25). This is a quartic polynomial, which can be solved by the polynomial solution method.

[0072]

[0073] A=1

[0074]

[0075]

[0076]

[0077]

[0078] in: is the initial amine solution concentration, mol / L; is the partial pressure of CO2, kPa; is the Henry constant of CO2 in water, kPa·L / mol.

[0079] However, the solution of a one-variable multi-time equation formed by eliminating multiple nonlinear equations has two disadvantages:

[0080] First, for high-order equations, there are multiple solutions in theory. By solving them in a multi-phase solution method, multiple solutions can be obtained, and usually only one of these solutions has real physical meaning. There is still a lack of reliable theoretical basis for how to select the correct root, and it is usually selected based on experience.

[0081] Second, for the amine-acid system containing carbon dioxide and hydrogen sulfide or polyamine liquid, due to the complex reaction equation and the large number of chemical equilibrium equations, it is usually very difficult to derive a single variable high-order equation by elimination. In most cases, it is impossible to organize it into a polynomial by elimination. Therefore, this method is mostly used for the calculation of a system where a single amine liquid absorbs a single acid gas.

[0082] Regarding the problem of solving the chemical equilibrium of the mathematical model of the amine acid system in a natural gas purification plant, the above two existing solution methods are unstable and cannot solve the problem of complex amine acid systems. Therefore, an embodiment of the present invention proposes a method for solving the chemical equilibrium of the amine acid system in a natural gas purification plant.

[0083] Figure 1 The flowchart of the method for solving the chemical equilibrium of the amine acid system in the natural gas purification plant according to the embodiment of the present invention includes:

[0084] Step 101, obtaining multiple reaction formulas of chemical equilibrium of a mathematical model of an amine acid system in a natural gas purification plant;

[0085] Step 102, determining the current concentration of each ion involved in each reaction formula as the initial concentration;

[0086] Step 103, determining the current value of the equilibrium constant in each reaction formula as an initial value;

[0087] Step 104, for each reaction formula, iteratively perform the following steps until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and output the latest concentration of each ion involved in the reaction formula:

[0088] Step 105, based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, a reaction amount solution formula is used to solve the reaction amount of the reaction formula;

[0089] Step 106, calculating the latest concentration of each ion according to the reaction amount and the current concentration of each ion;

[0090] Step 107, updating the current concentration of each ion and the current value of the equilibrium parameter.

[0091] Figure 2 This is a flow chart of determining a reaction amount solution formula in an embodiment of the present invention. In one embodiment, the method further includes:

[0092] Use the following steps to determine the reaction amount and solve the formula:

[0093] Step 201, constructing a general reaction formula of chemical equilibrium of a mathematical model of an amine acid system in a natural gas purification plant;

[0094] The general reaction formula of the chemical equilibrium of the mathematical model of the amino acid system in the natural gas purification plant is as follows:

[0095]

[0096] Among them, A, B, C, and D are ions;

[0097] Step 202, according to the general reaction formula, determining the equilibrium constant expression when the solution of the amino acid system reaches equilibrium;

[0098] The equilibrium constant expression is as follows:

[0099]

[0100] Where K is the equilibrium constant, n is the amount of reaction, are the molar concentrations of ions A, B, C, and D, respectively;

[0101] Step 203, expanding the equilibrium constant expression into a polynomial form of the reaction quantity;

[0102] The polynomial form of the reaction volume is expressed as follows:

[0103]

[0104] Step 204, obtaining two roots of the reaction quantity solution formula according to the polynomial form of the reaction quantity;

[0105] The two roots of the reaction amount solution formula are expressed as follows:

[0106]

[0107] AA=(K-1)

[0108]

[0109]

[0110]

[0111] Step 205, determine the final reaction quantity solution formula from the two roots of the reaction quantity solution formula. Determine the reaction quantity solution formula.

[0112] For the solution formula of formula (29), normally there are two roots, and only one root is the root of the solution with real physical meaning. Physical meaning analysis is performed to obtain the solution with physical meaning as formula (30), which is the final solution formula for the reaction quantity.

[0113]

[0114] The analysis process of the real physical solution:

[0115] If the initial value =0, the chemical reaction equation can only proceed from left to right, so the obtained n must be greater than 0. Use this characteristic to analyze the two cases of the root formula. Since the equilibrium constant K is very small, usually less than 1, AA = (K-1) < 0, and from the expression of BB, we know that BB < 0. Since the initial conditions of the reaction equation only have reactants and no products,

[0116] 1) Assume that the solution formula for n is:

[0117] Because AA<0, CC>0, so

[0118] From this we can get:

[0119] The reaction proceeded in the reverse direction, which was inconsistent with the hypothesis.

[0120] 2) Assume that the solution formula for n is

[0121] Because AA<0, CC>0, so

[0122] From this we can get:

[0123] The reaction proceeded in the forward direction, which was consistent with the hypothesis.

[0124] In step 101, multiple reaction formulas of the chemical equilibrium of the mathematical model of the amino acid system of the natural gas purification plant, that is, formula (1)-formula (8), are obtained, and the current concentration of each ion involved in each reaction formula is determined as the initial concentration and the initial value of the equilibrium constant in each reaction formula. Then, iterative calculation is performed, mainly based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, and the reaction amount solution formula (30) is used to solve the reaction amount of the reaction formula. According to the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated. When the iteration is stopped, the latest concentration of each ion involved in each reaction formula is output. The difference between the latest concentration and the current concentration can be determined according to the situation within a preset range. For example, it can be

[0125] For example, for the reaction formula represented by formula (26), When the calculated reaction amount is 2 mol / kg, the initial concentration of A is 3 mol / kg, and the reaction direction is from left to right, the final concentration of A is 3 mol / kg-2 mol / kg=1 mol / kg, thereby achieving chemical equilibrium.

[0126] Several specific embodiments are given below to illustrate the effectiveness of the method proposed in the embodiment of the present invention.

[0127] Embodiment 1

[0128] MDEA concentration: 4.28M, CO2 loading: 0.532, system temperature: 373.15K.

[0129] Iteration Stability:

[0130] Comparing the convergence process of the Newton-Raphson method and the method (called the iterative method) proposed in the embodiment of the present invention, as shown in FIG. Figure 3 shown. Figure 3 (a) shows the CO 2 The convergence curve of Figure 3 (b) shows the H + The Newton-Raphson method has a greater fluctuation in the iteration process than the iterative method. The iterative method can calculate the equilibrium concentration of the current equation at each iteration step, so it has better stability and higher efficiency.

[0131] Embodiment 2

[0132] MDEA concentration: 4.28 mol / L, temperature: 393.15 K

[0133] Results stability:

[0134] The solution results under different pressure conditions are shown in Table 2. By comparing the solution results in Table 1 and Table 2, it can be found that the solution results of the iterative method can obtain correct results under both high pressure conditions and low pressure conditions, and have good stability.

[0135] Table 2 Iterative solution results

[0136]

[0137]

[0138] Embodiment 3

[0139] MDEA concentration: 4.28 mol / L, temperature: 298.15K, 343.15K and 393.15K.

[0140] Result analysis:

[0141] Calculation of CO 2 The equilibrium solubility in MDEA solution. The calculated results are compared with a set of actual experimental data. Figure 4 As shown, from Figure 4 Analysis shows that the Newton-Raphson method cannot obtain correct results under low pressure conditions when calculating at 393.15K, while the iterative method can obtain correct results in the entire temperature and pressure range.

[0142] In summary, in the method proposed in the embodiment of the present invention, multiple reaction formulas of the chemical equilibrium of the mathematical model of the amino acid system of the natural gas purification plant are obtained; the current concentration of each ion involved in each reaction formula is determined as the initial concentration; the current value of the equilibrium constant in each reaction formula is determined as the initial value; for each reaction formula, the following steps are iteratively performed until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and the latest concentration of each ion involved in the reaction formula is output: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, the reaction amount of the reaction formula is solved using a reaction amount solution formula; based on the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated; and the current concentration of each ion and the current value of the equilibrium parameter are updated. Compared with the technical solutions of the prior art that use the Newton-Raphson method and the polynomial method to solve chemical equilibrium, the latest concentration of each ion is updated by iteratively using the reaction amount solution formula to solve the reaction amount of each reaction equation until the difference between the latest concentration of each ion involved in the reaction equation and the current concentration is within a preset range, that is, the equilibrium of the ion concentration is achieved. Since a given initial value is not required, the solution process is stable, and it can be used for complex multi-reaction equations with high solution efficiency.

[0143] The present invention also provides a device for solving the chemical balance of the amine acid system in a natural gas purification plant, as described in the following embodiments. Since the principle of solving the problem by the device is similar to the method for solving the chemical balance of the amine acid system in a natural gas purification plant, the implementation of the device can refer to the implementation of the method for solving the chemical balance of the amine acid system in a natural gas purification plant, and the repeated parts will not be repeated.

[0144] Figure 5 Schematic diagram of a chemical equilibrium solving device for an amine acid system in a natural gas purification plant according to an embodiment of the present invention Figure 1 ,include:

[0145] A reaction formula obtaining module 501 is used to obtain multiple reaction formulas of chemical equilibrium of the mathematical model of the amine acid system of the natural gas purification plant;

[0146] An ion concentration determination module 502 is used to determine the current concentration of each ion involved in each reaction formula as the initial concentration;

[0147] An equilibrium constant determination module 503, used to determine the current value of the equilibrium constant in each reaction formula as an initial value;

[0148] The iteration module 504 is used to iteratively perform the following steps for each reaction formula until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and output the latest concentration of each ion involved in the reaction formula: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, the reaction amount of the reaction formula is solved using the reaction amount solution formula; based on the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated; and the current concentration of each ion and the current value of the equilibrium parameter are updated.

[0149] Figure 6 Schematic diagram of a chemical equilibrium solving device for an amine acid system in a natural gas purification plant according to an embodiment of the present invention Figure 2 In one embodiment, the device further comprises a reaction quantity solution formula determination module 601, which is used to:

[0150] Use the following steps to determine the reaction amount and solve the formula:

[0151] Construct the general reaction formula of chemical equilibrium of the mathematical model of the amino acid system in the natural gas purification plant;

[0152] According to the general reaction formula, determine the equilibrium constant expression when the solution of the amino acid system reaches equilibrium;

[0153] Expand the equilibrium constant expression into a polynomial form for the reactants;

[0154] According to the polynomial form of the reaction quantity, two roots of the reaction quantity solution formula are obtained;

[0155] From the two roots of the reaction solution, determine the final reaction solution.

[0156] In one embodiment, the iteration module is specifically used for:

[0157] According to the latest concentration of each ion involved in the reaction formula, the current value of the equilibrium parameter is calculated using the equilibrium constant expression corresponding to the reaction formula;

[0158] Update the current concentration of each ion to the latest concentration of each ion.

[0159] In summary, in the device proposed in the embodiment of the present invention, multiple reaction formulas of the chemical equilibrium of the mathematical model of the amino acid system of the natural gas purification plant are obtained; the current concentration of each ion involved in each reaction formula is determined as the initial concentration; the current value of the equilibrium constant in each reaction formula is determined as the initial value; for each reaction formula, the following steps are iteratively performed until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and the latest concentration of each ion involved in the reaction formula is output: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, the reaction amount of the reaction formula is solved using a reaction amount solution formula; based on the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated; and the current concentration of each ion and the current value of the equilibrium parameter are updated. Compared with the technical solutions of the prior art that use the Newton-Raphson method and the polynomial method to solve chemical equilibrium, the latest concentration of each ion is updated by iteratively using the reaction amount solution formula to solve the reaction amount of each reaction equation until the difference between the latest concentration of each ion involved in the reaction equation and the current concentration is within a preset range, that is, the equilibrium of the ion concentration is achieved. Since a given initial value is not required, the solution process is stable, and it can be used for complex multi-reaction equations with high solution efficiency.

[0160] An embodiment of the present invention further provides a computer device, Figure 7 Schematic diagram of a computer device in an embodiment of the present invention, wherein the computer device 700 includes a memory 710, a processor 720, and a computer program 730 stored in the memory 710 and executable on the processor 720. When the processor 720 executes the computer program 730, the above-mentioned method for solving the chemical equilibrium of the amine acid system in the natural gas purification plant is implemented.

[0161] An embodiment of the present invention further 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 above-mentioned method for solving the chemical equilibrium of the amine-acid system of a natural gas purification plant is implemented.

[0162] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for solving the chemical equilibrium of the amine-acid system in the natural gas purification plant is implemented.

[0163] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0164] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0165] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0166] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0167] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for solving the chemical equilibrium of an amine acid system in a natural gas purification plant, characterized in that: include: Obtain multiple reaction equations of chemical equilibrium of the mathematical model of the amine acid system of the natural gas purification plant; Determine the current concentration of each ion involved in each reaction equation as the initial concentration; Determine the current value of the equilibrium constant in each reaction equation as the initial value; For each reaction formula, the following steps are iteratively performed until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and the latest concentration of each ion involved in the reaction formula is output: Based on the current concentration of each ion involved in the reaction equation and the current value of the equilibrium constant, the reaction amount of the reaction equation is solved using a reaction amount solution formula; Calculate the latest concentration of each ion based on the reaction amount and the current concentration of each ion; Update the current concentration of each ion and the current value of the equilibrium parameter; The method also includes: determining a reaction amount solution formula by the following steps: constructing a general reaction formula of the chemical equilibrium of the mathematical model of the amino acid system of the natural gas purification plant; determining, according to the general reaction formula, an equilibrium constant expression when the solution of the amino acid system reaches equilibrium; expanding the equilibrium constant expression into a polynomial form of the reaction amount; obtaining two roots of the reaction amount solution formula according to the polynomial form of the reaction amount; and determining a final reaction amount solution formula from the two roots of the reaction amount solution formula; The general reaction formula of the chemical equilibrium of the mathematical model of the amino acid system in the natural gas purification plant is as follows: The equilibrium constant expression is as follows: The polynomial form of the reaction volume is expressed as follows: The two roots of the reaction amount solution formula are expressed as follows: AA=(K-1) The final reaction amount solution formula is expressed as follows: Among them, A, B, C, and D are ions; K is the equilibrium constant, and n is the amount of reaction. are the molar concentrations of ions A, B, C, and D, respectively; The chemical equilibrium reaction equations of the mathematical model of the amine acid system in the natural gas purification plant include: Among them, each reaction is bidirectional; The equilibrium constant expression of the reaction is as follows: Where: K i is the chemical equilibrium constant; x i is the molar concentration of the ion.

2. The method according to claim 1, characterized in that Updates the current concentration of each ion and the current values ​​of equilibrium parameters, including: According to the latest concentration of each ion involved in the reaction formula, the current value of the equilibrium parameter is calculated using the equilibrium constant expression corresponding to the reaction formula; Update the current concentration of each ion to the latest concentration of each ion.

3. A chemical equilibrium solving device for an amine acid system in a natural gas purification plant, characterized in that: include: A reaction formula acquisition module is used to obtain multiple reaction formulas of chemical equilibrium of the mathematical model of the amine acid system of the natural gas purification plant; An ion concentration determination module, used to determine the current concentration of each ion involved in each reaction formula as the initial concentration; An equilibrium constant determination module, used to determine the current value of the equilibrium constant in each reaction formula as an initial value; The iterative module is used to iteratively perform the following steps for each reaction formula until the difference between the latest concentration and the current concentration of each ion involved in the reaction formula is within a preset range, and output the latest concentration of each ion involved in the reaction formula: based on the current concentration of each ion involved in the reaction formula and the current value of the equilibrium constant, the reaction amount of the reaction formula is solved by using a reaction amount solution formula; according to the reaction amount and the current concentration of each ion, the latest concentration of each ion is calculated; and the current concentration of each ion and the current value of the equilibrium parameter are updated; The method also includes: determining a reaction amount solution formula by the following steps: constructing a general reaction formula of the chemical equilibrium of the mathematical model of the amino acid system of the natural gas purification plant; determining, according to the general reaction formula, an equilibrium constant expression when the solution of the amino acid system reaches equilibrium; expanding the equilibrium constant expression into a polynomial form of the reaction amount; obtaining two roots of the reaction amount solution formula according to the polynomial form of the reaction amount; and determining a final reaction amount solution formula from the two roots of the reaction amount solution formula; The general reaction formula of the chemical equilibrium of the mathematical model of the amino acid system in the natural gas purification plant is as follows: The equilibrium constant expression is as follows: The polynomial form of the reaction volume is expressed as follows: The two roots of the reaction amount solution formula are expressed as follows: AA=(K-1) The final reaction amount solution formula is expressed as follows: Among them, A, B, C, and D are ions; K is the equilibrium constant, and n is the amount of reaction. are the molar concentrations of ions A, B, C, and D, respectively; The chemical equilibrium reaction equations of the mathematical model of the amine acid system in the natural gas purification plant include: Among them, each reaction is bidirectional; The equilibrium constant expression of the reaction is as follows: Where: K i is the chemical equilibrium constant; x i is the molar concentration of the ion.

4. A computer device 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 method according to any one of claims 1 to 2 is implemented.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 2 is implemented.

6. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 2 is implemented.

Images