Process parameter determination method for preparing hydrogen-based reducing gas process based on carbon precipitation control

Abstract

The application provides a process parameter determination method of a hydrogen-based reducing gas preparation process based on carbon precipitation control, which comprises the following steps: calculating the degrees of freedom of a hydrogen-based reducing gas preparation process system under a critical carbon precipitation balance condition; determining a physical quantity parameter that can be independently changed and has a strength property in the hydrogen-based reducing gas preparation process system according to the degrees of freedom under the critical carbon precipitation balance condition, and obtaining a balance gas phase composition function under the critical carbon precipitation balance condition; drawing an H-C-O two-dimensional graph with the mole ratio of H and C as the ordinate and the mole ratio between O and C as the abscissa; using the balance gas phase composition function to represent the O / C mol ratio and the H / C mol ratio in the hydrogen-based reducing gas preparation process system, and obtaining a drawing calculation formula of a critical carbon precipitation point in the H-C-O two-dimensional graph; assigning values to the physical quantity parameters, drawing a critical carbon precipitation curve in the H-C-O two-dimensional graph according to the drawing calculation formula of the critical carbon precipitation point based on the assigned physical quantity parameters, and determining the process parameters of the hydrogen-based reducing gas preparation process based on carbon precipitation control according to the critical carbon precipitation curve.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to a method for determining process parameters for a process of preparing hydrogen-based reducing gas based on controlled carbon evolution. Background Technology

[0002] With the active promotion of carbon emission reduction and carbon neutrality, gas-based direct reduction, especially hydrogen-based direct reduction of iron, will see significant development. Therefore, the preparation of hydrogen-based reducing gas is crucial. However, in the process of preparing reducing gas from natural gas or coke oven gas, improper control of operating parameters can lead to carbon precipitation side reactions, which in turn can affect the stability and efficiency of the hydrogen-rich gas preparation process.

[0003] In the existing processes for producing reducing gas from natural gas or coke oven gas, there is a lack of theoretical basis for selecting process parameters that can control carbon precipitation in the process of producing hydrogen-based reducing gas. The process parameters such as the addition ratio, conversion temperature, and total system pressure of natural gas and coke oven gas during steam or CO2 reforming are basically based on experience, and there is a lack of a convenient, simple and fast method for determining process parameters. Summary of the Invention

[0004] In view of the above problems, this invention proposes a method for determining process parameters for the preparation of hydrogen-based reducing gas based on controlled carbon evolution. Based on the phase rule and the equilibrium principle of a multi-species reaction system, and on the basis of constructing a mass and chemical equilibrium diagram of the HCO system, this invention provides a method for determining process parameters such as temperature and pressure for the preparation of hydrogen-rich reducing gas that can control carbon evolution and meet the requirements for direct iron reduction. This method has important theoretical significance and practical guiding role.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon evolution includes:

[0007] The degrees of freedom of the process system for preparing hydrogen-based reducing gas under critical carbon evolution equilibrium conditions were calculated, and the degree of freedom was found to be 3.

[0008] Based on the degrees of freedom under the critical carbon evolution equilibrium condition, the physical quantity parameters that can vary independently and have strong properties in the process system for preparing hydrogen-based reducing gas are determined, and the equilibrium gas phase composition function under the critical carbon evolution equilibrium condition is obtained.

[0009] Plot a two-dimensional HCO3-Phase graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa.

[0010] The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation process system are characterized by the equilibrium gas phase composition function, respectively, and the calculation formula for plotting the critical carbon precipitation point in the two-dimensional HCO diagram is obtained.

[0011] The physical quantity parameters are assigned values, and based on the assigned physical quantity parameters, a critical carbon precipitation curve is plotted on the HCO two-dimensional graph according to the calculation formula for plotting the critical carbon precipitation point. The process parameters for the hydrogen-based reducing gas preparation process that control carbon precipitation are determined based on the critical carbon precipitation curve.

[0012] Furthermore, the degrees of freedom for calculating the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions are found to be 3, including:

[0013] When the hydrogen-based reducing gas preparation process system is under critical carbon evolution equilibrium conditions, it is determined that the hydrogen-based reducing gas preparation process system contains six material components: gaseous CH4, CO2, CO, H2O, H2, and solid C; the degrees of freedom of the hydrogen-based reducing gas preparation process system are calculated according to the phase rule expression, including:

[0014] The phase law expression is:

[0015] Wherein, C′ is the number of species present in the process system for preparing hydrogen-based reducing gas, C′=6; r is the number of independent reactions in the process system for preparing hydrogen-based reducing gas, r=6-3+0=3; The number of phases in the process system for preparing hydrogen-based reducing gas is given.

[0016] The calculated degree of freedom of the process system for preparing hydrogen-based reducing gas is f = 3.

[0017] Furthermore, the determination of independently variable and intensive physical quantity parameters in the hydrogen-based reducing gas preparation process system based on the degrees of freedom under the critical carbon evolution equilibrium condition, to obtain the equilibrium gas phase composition function under the critical carbon evolution equilibrium condition, includes:

[0018] If the total system pressure P, reforming temperature T, and H2 / COmol ratio are selected as the physical quantity parameters, then the equilibrium gas phase composition function is:

[0019] Furthermore, the method also includes:

[0020] The system of raw material gases contains only three gases: CH4, H2O, and CO2. In the two-dimensional HCO diagram, the corresponding coordinates of pure CH4 gas, pure CO gas, and pure CO2 gas are determined to be (0, 4), (1, 0), and (2, 0), respectively.

[0021] Using the formulas H2O+CH4>0 and CO2=0, draw the L1 line in the two-dimensional HCO diagram; using the formulas CO2+CH4>0 and H2O=0, draw the L2 line in the two-dimensional HCO diagram.

[0022] Based on the molar ratio between H2O and CH4, draw radial straight lines through the point (2, 0) in the HCO two-dimensional diagram to plot the H2O / CH4 scale.

[0023] Draw a straight line parallel to line L1 in the HCO 2D diagram to plot the CO2 / CH4 scale.

[0024] Furthermore, the method of using the equilibrium gas phase composition function to characterize the O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation process system, and obtaining the calculation formula for plotting the critical carbon precipitation point in the HCO two-dimensional diagram, includes:

[0025] The mol fractions of the material components CO, H2O, CO2, H2, and CH4 in the process system for preparing hydrogen-based reducing gas are represented by x1, x2, x3, x4, and x5, respectively.

[0026] The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation system are characterized using the equilibrium gas phase composition function as follows:

[0027]

[0028]

[0029] Where P is the total pressure of the system, in atm; and T is the reforming temperature, in °C.

[0030] Furthermore, the calculation formula for plotting the critical carbon precipitation point in the HCO two-dimensional diagram also includes the calculation formula for the equilibrium gas composition within the hydrogen-based reducing gas preparation process system; the method further includes:

[0031] Calculate the molar fraction x of the substance in the hydrogen-based reducing gas preparation process system based on three independent reactions under equilibrium conditions. i The relationship with the equilibrium constant includes:

[0032] Based on reaction 1: CO2 + C = 2CO, we obtain...

[0033] Based on reaction 2: CO + H₂O = H₂ + CO₂, we obtain...

[0034] According to reaction 3: CH4=C+2H2, we obtain...

[0035] Based on the above equilibrium constant calculation formula, the mol fractions of CO2, H2O, and H2 are as follows:

[0036]

[0037]

[0038]

[0039] Based on the fact that the mol fractions of the equilibrium gases of each component in the hydrogen-based reducing gas preparation process system are summed to 1, we obtain:

[0040]

[0041] Meanwhile, the following preset conditions are configured for the process system for preparing hydrogen-based reducing gas:

[0042]

[0043] P = P tot (8);

[0044] T = T 重整 (9);

[0045] Equations (3) to (9) above are the calculation formulas for the equilibrium gas composition in the process system for preparing hydrogen-based reducing gas;

[0046] Among them, α c P represents the activity of carbon in its pure state, with a value of 1. tot The preset total system pressure is expressed in atm; T 重整 This is the preset system reforming temperature, in °C.

[0047] Furthermore, the process of assigning values ​​to the physical quantity parameters, plotting a critical carbon deposition curve on the HCO2 two-dimensional graph based on the calculated formula for the critical carbon deposition point according to the assigned physical quantity parameters, and determining the process parameters for the hydrogen-based reducing gas preparation process to control carbon deposition based on the critical carbon deposition curve includes:

[0048] Under the preset constant pressure P tot , Under given conditions, the first critical carbon deposition curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon deposition point. The first critical carbon deposition curve is used to characterize different reforming temperatures T. 重整 The coordinates of the lower critical carbon precipitation point in the two-dimensional HCO3-D diagram;

[0049] Using the first critical carbon deposition curve in combination with H2O / CH4 and CO2 / CH4 scales, the constant pressure P was determined. tot , Reforming temperature T 重整 The ideal water-carbon ratio for controlling carbon precipitation under the corresponding conditions That is, to determine the process parameters for the preparation of hydrogen-based reducing gas to control carbon precipitation.

[0050] Furthermore, the method also includes:

[0051] Under the preset constant pressure P tot , Under given conditions, different reforming temperatures T are determined based on the first critical carbon deposition curve. 重整 The first correspondence between the equilibrium gas mol fractions of each component;

[0052] Based on the first correspondence, the preset constant pressure P is determined. tot , Under given conditions, the process for preparing hydrogen-based reducing gas satisfies the preset requirement of reforming temperature parameters when H2 + CO = B.

[0053] Furthermore, the method also includes:

[0054] At the preset reforming temperature T 重整 ,different Under given conditions, the second critical carbon deposition curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon deposition point. The second critical carbon deposition curve is used to characterize the total pressure P of different systems. tot ,different The coordinates of the critical carbon deposition point under the given conditions in the two-dimensional HCO3-D diagram;

[0055] Based on the second critical carbon deposition curve, the preset reforming temperature T is determined. 重整 , Under given conditions, the total pressure P of the hydrogen-based reducing gas preparation process system under equilibrium conditions for different systems is... tot The second correspondence between the equilibrium gas mol fractions of each component;

[0056] Based on the second correspondence, the preset reforming temperature T is determined. 重整 , Under given conditions, the total pressure parameters of the hydrogen-based reducing gas preparation process system when H2+CO=B meet the preset requirement.

[0057] Furthermore, the method also includes:

[0058] The second critical carbon deposition curve is used to determine the reaction temperature at the preset reforming temperature T. 重整 Total pressure P of different systemstot ,different The variation law of carbon precipitation under the conditions described in the hydrogen-based reducing gas preparation process is used to determine the process parameters of the hydrogen-based reducing gas preparation process system.

[0059] This invention provides a method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon evolution. The method involves calculating the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions; determining independently variable physical quantity parameters with intensive properties in the process system based on these degrees of freedom, thus obtaining the equilibrium gas phase composition function under the critical carbon evolution equilibrium conditions; plotting a two-dimensional HCO2 graph with the molar ratio of H and C as the ordinate and the molar ratio of O and C as the abscissa; using the equilibrium gas phase composition function to characterize the O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation process system, obtaining the calculation formula for plotting the critical carbon evolution point in the HCO2 graph; assigning values ​​to the physical quantity parameters; plotting a critical carbon evolution curve in the HCO2 graph based on the assigned values ​​and the calculation formula for plotting the critical carbon evolution point; and determining the process parameters for the controlled carbon evolution process of the hydrogen-based reducing gas preparation process based on the critical carbon evolution curve. This invention solves the technical problem in the prior art of being unable to determine the process parameters such as the preparation temperature and pressure of hydrogen-rich reducing gas that can control carbon precipitation and meet the requirements of direct iron reduction by establishing a mass and chemical equilibrium calculation based on the HCO system. It provides a theoretical basis and a convenient way to determine the process parameters for preparing hydrogen-based reducing gas using various gas sources (such as natural gas or coke oven gas).

[0060] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below.

[0061] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0062] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0063] Figure 1A flowchart illustrating a method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon deposition, provided by an exemplary embodiment of the present invention, is shown.

[0064] Figure 2 This illustrates a two-dimensional HCO diagram and a given P provided by an exemplary embodiment of the present invention. tot and The first critical carbon evolution curve under the given conditions;

[0065] Figure 3 This illustrates a given P provided by an exemplary embodiment of the present invention. tot The first correspondence between reforming temperature and the composition of each equilibrium gas under the conditions of A=1 atm, A=2 (left) and A=5 (right);

[0066] Figure 4 The present invention illustrates a given A = 2, T... 重整 =600℃ (left) and T 重整 The second corresponding diagram of the relationship between the total pressure of the system and the composition of each equilibrium gas under the condition of 900℃ (right);

[0067] Figure 5 The present invention illustrates a given A = 2, T... 重整 =600℃ (left) and T 重整 The third corresponding graph showing the relationship between the total pressure of the system and the molar fraction of the effective component (H2+CO) under the condition of 900℃ (right);

[0068] Figure 6 This illustrates a given P provided by an exemplary embodiment of the present invention. tot The fourth graph showing the relationship between reforming temperature and the total molar fraction of effective component (H2+CO) under the conditions of 1 atm, A=2 (left) and A=5 (right);

[0069] Figure 7 This illustrates a given P provided by an exemplary embodiment of the present invention. tot =1 atm, T 重整 =600℃ (left) and T 重整 The fifth correspondence diagram between H2 / CO and the composition of each equilibrium gas under the condition of 900℃ (right);

[0070] Figure 8 This illustrates a two-dimensional HCO diagram and a given T provided by an exemplary embodiment of the present invention. 重整 and Under certain conditions, the second critical carbon deposition curve shows the carbon deposition region as a function of total pressure. Detailed Implementation

[0071] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0072] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0073] This invention provides a method for determining process parameters in a process for preparing hydrogen-based reducing gas based on controlled carbon evolution, such as... Figure 1 As shown, the method may include at least the following steps S101 to S105:

[0074] Step S101: Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and obtain a degree of freedom of 3.

[0075] In the process system for preparing hydrogen-based reducing gas, carbon evolution side reactions are prone to occur. If the system is in the critical carbon evolution state, there will be six substances in the system: CO, H2O, CO2, H2, CH4 and solid C. When the system reaches equilibrium, the mol fractions of the components CO, H2O, CO2, H2 and CH4 in the system can be set as x1, x2, x3, x4 and x5, respectively.

[0076] Specifically, the degrees of freedom of the hydrogen-based reducing gas preparation process system can be calculated based on the phase rule expression in thermodynamics. The phase rule expression is as follows:

[0077] Where C′ represents the number of species present in the process system for preparing hydrogen-based reducing gas. Since there are six substances in the system, namely CO, H2O, CO2, H2, CH4 and solid C, C′ = 6. r represents the number of independent reactions in the process system for preparing hydrogen-based reducing gas. Since the carbon element in the system undergoes a change in valence state, r = 6 - 3 + 0 = 3. To prepare hydrogen-based reducing gas, the process system includes both gaseous and solid phases.

[0078] From the above phase rule expression and parameters, it can be calculated that the system has 3 degrees of freedom f when it reaches equilibrium. That is to say, the gas phase composition of the system at equilibrium is determined by 3 physical quantities that can change independently and have strong properties. As long as the 3 physical quantities that can change independently and have strong properties are determined, the material composition of the system at equilibrium is determined and obtainable.

[0079] Step S102: Based on the degrees of freedom under the critical carbon evolution equilibrium condition, determine the physical quantity parameters that can vary independently and have intensive properties in the process system for preparing hydrogen-based reducing gas, and obtain the equilibrium gas phase composition function under the critical carbon evolution equilibrium condition.

[0080] Under critical carbon evolution equilibrium conditions, the process system for preparing hydrogen-based reducing gas has certain total system pressure P and system temperature T. Furthermore, according to the requirements for preparing hydrogen-based reducing gas, the system's material composition must meet the following requirements:

[0081]

[0082] Therefore, in this embodiment of the invention, the total system pressure P, reforming temperature T, and the H2 / COmol ratio required for preparing hydrogen-based reducing gas are selected as physical quantity parameters. Based on the given total system pressure P, reforming temperature T, and... The value can then be used to determine the gas phase composition of the system at the critical carbon precipitation state. Therefore, the equilibrium gas phase composition function of the hydrogen-based reducing gas preparation process system at the critical carbon precipitation state can be determined as follows:

[0083] Step S103: Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the vertical axis and the molar ratio between O and C as the horizontal axis.

[0084] Specifically, such as Figure 2As shown, when drawing the HCO two-dimensional diagram, it is assumed that the raw material gas system contains only three gases: CH4, H2O, and CO2. The coordinate positions of pure CH4, pure CO, and pure CO2 in the HCO two-dimensional diagram are determined as points (0, 4), (1, 0), and (2, 0), respectively. The L1 line is drawn on the HCO two-dimensional diagram with H2O + CH4 > 0 and CO2 = 0, the L2 line is drawn on the HCO two-dimensional diagram with CO2 + CH4 > 0 and H2O = 0, and the L3 line is drawn on the HCO two-dimensional diagram with CO2 / CH4 → ∞. According to the molar ratio between H2O and CH4, radial lines are drawn through the point (2, 0) in the HCO two-dimensional diagram to draw the H2O / CH4 scale. A line parallel to the L1 line is drawn on the HCO two-dimensional diagram to draw the CO2 / CH4 scale, so as to obtain the complete HCO two-dimensional diagram.

[0085] Step S104: The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained.

[0086] The process system for preparing hydrogen-based reducing gas in this embodiment of the invention is based on a given total system pressure P, reforming temperature T, and... Under certain conditions, the equilibrium gas phase composition at the critical carbon deposition state can be determined, i.e., by using the equilibrium gas phase composition function. Characterizes the equilibrium gas phase of the system at the critical carbon precipitation state.

[0087] Therefore, the O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation system can be characterized using the equilibrium gas phase composition function as follows:

[0088]

[0089]

[0090] Where P is the total pressure of the system, in atm; and T is the reforming temperature, in °C.

[0091] Furthermore, the hydrogen-based reducing gas preparation process system in this embodiment of the invention involves the following three independent chemical reactions when the system reaches equilibrium:

[0092] Reaction 1: CO2 + C = 2CO;

[0093] Reaction 2: CO + H₂O = CO₂ + H₂;

[0094] Reaction 3: CH4=C + 2H2;

[0095] The standard Gibbs free energy changes for the above reactions are as follows:

[0096]

[0097]

[0098]

[0099] When the system is in the critical carbon evolution state, the six substances in the system (CO, H2O, CO2, H2, CH4, and solid C) coexist in equilibrium. If pure carbon is taken as the standard state, then the activity α of carbon in the critical carbon evolution state is... c =1, while the mol fractions (x1, x2, x3, x4 and x5) of the other components CO, H2O, CO2, H2 and CH4 are constant values.

[0100] The equilibrium constant for the above reaction is calculated using the following formula:

[0101] Reaction 1:

[0102] Reaction 2:

[0103] Reaction 3:

[0104] Pure carbon is chosen as the standard state of carbon activity, i.e., α. c＝1 When the system reaches equilibrium, the mol fractions of CO2, H2O, and H2, calculated using the above equilibrium constant formula, are as follows:

[0105]

[0106]

[0107]

[0108] Furthermore, based on the fact that the sum of the mol fractions of the equilibrium gases of each component in the process system for preparing hydrogen-based reducing gas is 1, we obtain:

[0109]

[0110] Meanwhile, the following preset conditions can be configured for the hydrogen-based reducing gas preparation process system:

[0111]

[0112] P = P tot (8);

[0113] T = T 重整 (9); where Ptot The preset total system pressure is expressed in atm; T 重整 The preset system reforming temperature is given in °C. It is understood that the hydrogen-based reducing gas preparation process system in this embodiment of the invention operates at a given total system pressure P. tot Reforming temperature T 重整 , Under the condition that A is a constant, the gas phase composition and mol fraction of each component when the system is in the critical carbon precipitation state can be calculated according to the above formulas (3) to (9). Therefore, the above formulas (3) to (9) are determined as the calculation formulas for the equilibrium gas composition in the process system for preparing hydrogen-based reducing gas, and combined with the calculation formulas (1) to (2) are used for the subsequent drawing of the critical carbon precipitation curve in the two-dimensional HCO diagram.

[0114] Step S105: Assign values ​​to the physical quantity parameters, and based on the assigned physical quantity parameters, plot the critical carbon precipitation curve in the HCO two-dimensional graph according to the calculation formula for plotting the critical carbon precipitation point. Determine the process parameters for the hydrogen-based reducing gas preparation process that controls carbon precipitation based on the critical carbon precipitation curve.

[0115] The process system for preparing hydrogen-based reducing gas in this embodiment of the invention, if the total system pressure P is selected... tot Reforming temperature T 重整 as well as Using these three independently variable physical quantities with intensive properties as parameters, the gas phase composition in the system at the critical carbon precipitation state can be determined. That is, based on the calculation formulas (1) to (9) for plotting the critical carbon precipitation curve in the above steps, once the total pressure P of the system is... tot Reforming temperature T 重整 as well as By assigning values, the molal composition of each component at the critical carbon evolution state of the system can be calculated, which is reflected as a fixed point in the HCO2 two-dimensional diagram. If the total pressure P of the system... tot Reforming temperature T 重整 as well as If two of these three physical parameters are assigned values, a critical carbon deposition curve can be plotted on the HCO two-dimensional graph. This critical carbon deposition curve is used to characterize the coordinate position of the critical carbon deposition point of the other physical parameter at different values ​​on the HCO two-dimensional graph.

[0116] Specifically, the total system pressure P can be preset. tot , Under given conditions, the first critical carbon precipitation curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon precipitation point. The first critical carbon precipitation curve is used to characterize different reforming temperatures T. 重整The coordinates of the lower critical carbon precipitation point in the two-dimensional HCO3-D diagram are determined, and then the total system pressure P is analyzed based on the first critical carbon precipitation curve. tot , Under certain conditions, the process parameters for preparing hydrogen-based reducing gas from carbon deposition can be controlled; additionally, the process parameters can be controlled at a preset reforming temperature T. 重整 ,different Given condition A, the second critical carbon deposition curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon deposition point. The second critical carbon deposition curve is used to characterize the total pressure P of different systems. tot ,different The coordinates of the critical carbon precipitation point in the two-dimensional HCO3-D diagram under the given conditions were determined, and then the second critical carbon precipitation curve was used to analyze the carbon precipitation at the reforming temperature T. 重整 , Process parameters for the preparation of hydrogen-based reducing gas under controlled carbon precipitation conditions.

[0117] This invention proposes a method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation. The method calculates the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon precipitation equilibrium conditions. Based on these degrees of freedom, it determines independently variable physical parameters with intensive properties within the process system, obtaining the equilibrium gas phase composition function under these conditions. A two-dimensional HCO2 graph is plotted with the molar ratio of H and C as the ordinate and the molar ratio of O and C as the abscissa. The equilibrium gas phase composition function is used to characterize the O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation process system, yielding a calculation formula for plotting the critical carbon precipitation point in the HCO2 graph. Values ​​are assigned to the physical parameters, and based on these values, a critical carbon precipitation curve is plotted on the HCO2 graph according to the calculation formula. The process parameters for controlling carbon precipitation in the hydrogen-based reducing gas preparation process are then determined based on the critical carbon precipitation curve. This invention, by establishing a mass and chemical equilibrium balance based on the HCO2 system, provides the total system pressure, reforming temperature, and desired reducing gas preparation parameters. The equilibrium gas phase composition at the critical carbonization state is determined under ratio conditions, and a method for determining the process parameters controlling carbonization behavior in the preparation of hydrogen-based reducing gas is provided. It can also determine the process parameters such as the conversion temperature and total pressure of the system that control the critical carbonization in the preparation of hydrogen-rich reducing gas. This solves the technical problem in the prior art that it is impossible to determine the process parameters such as the preparation temperature and pressure of hydrogen-rich reducing gas that control carbonization and meet the requirements of direct iron reduction. It provides a theoretical basis and a convenient way to determine the process parameters for preparing hydrogen-based reducing gas using various gas sources (such as natural gas or coke oven gas).

[0118] To further explain the method for determining process parameters in a process for preparing hydrogen-based reducing gas based on controlled carbon precipitation provided by the present invention, the following embodiments are further detailed.

[0119] Example 1:

[0120] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation includes:

[0121] a. Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and find that the degrees of freedom are 3;

[0122] b. Select the total pressure P tot Reforming temperature T 重整 And given that the H2 / COmol ratio = A is a physical quantity parameter, the equilibrium gas phase composition function is:

[0123] c. Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. Presuppose that the raw material gas system contains only CH4, H2O, and CO2. In the HCO2 graph, determine the corresponding coordinates of pure CH4, pure CO, and pure CO2 as points (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O + CH4 > 0 and CO2 = 0, draw the L1 line in the HCO2 graph. Using the formulas CO2 + CH4 > 0 and H2O = 0, draw the L2 line in the HCO2 graph. Based on the equal molar ratio between H2O and CH4, draw radial lines passing through point (2, 0) in the HCO2 graph to create an H2O / CH4 scale. Finally, draw a line parallel to the L1 line in the HCO2 graph to create a CO2 / CH4 scale.

[0124] d. The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained, including the above formulas (1) to (9).

[0125] e. Under the preset total system pressure P tot =1 atm Under given conditions, the first critical carbon precipitation curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon precipitation point, as follows: Figure 2 As shown, for each given A value (A = 1, 2, 5, 8), the left side of the first critical carbon deposition curve represents the carbon deposition region under that A value condition, and the right side represents the non-carbon deposition region.

[0126] f. Using the first critical carbon deposition curve in conjunction with the H2O / CH4 and CO2 / CH4 scales, determine the constant pressure P.tot , Reforming temperature T 重整 The ideal water-to-carbon ratio for controlling carbon precipitation under certain conditions is used to determine the process parameters for preparing hydrogen-based reducing gas to control carbon precipitation. For example, when A = 2, T... 重整 At 600℃, the H2O / CH4 ratio (equivalent to the water-to-carbon ratio in natural gas reforming) corresponding to the critical carbon deposition point (point R in the diagram) is approximately 2.0. It should be noted that industrially, the H2O / C ratio is generally used as the water-to-carbon ratio, while for natural gas reforming processes, the H2O / CH4 ratio is essentially equal to the H2O / C ratio. That is, at 1 atm and 600℃, the equilibrium gas... In order to control carbon precipitation in the system, the mol ratio of H2O to CH4 in the system should be greater than 2.0. In other words, the ideal water-to-carbon ratio at 1 atm and 600℃ is 2.0.

[0127] Example 2:

[0128] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation includes:

[0129] a. Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and find that the degrees of freedom are 3;

[0130] b. Select the total pressure P tot Reforming temperature T 重整 And given that the H2 / COmol ratio = A is a physical quantity parameter, the equilibrium gas phase composition function is:

[0131] c. Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. Presuppose that the raw material gas system contains only CH4, H2O, and CO2. In the HCO2 graph, determine the corresponding coordinates of pure CH4, pure CO, and pure CO2 as points (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O + CH4 > 0 and CO2 = 0, draw the L1 line in the HCO2 graph. Using the formulas CO2 + CH4 > 0 and H2O = 0, draw the L2 line in the HCO2 graph. Based on the equal molar ratio between H2O and CH4, draw radial lines passing through point (2, 0) in the HCO2 graph to create an H2O / CH4 scale. Finally, draw a line parallel to the L1 line in the HCO2 graph to create a CO2 / CH4 scale.

[0132] d. The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained, including the above formulas (1) to (9).

[0133] e. Under the preset total system pressure P tot =1 atm Under given conditions, the first critical carbon precipitation curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon precipitation point. Based on the first critical carbon precipitation curve, the reforming temperature T for different conditions is determined. 重整 The first correspondence between the equilibrium gas mol fractions of each component;

[0134] f. Determine the total pressure P of the preset system based on the first correspondence relationship. tot , Under given conditions, determine the reforming temperature parameters for the process of preparing hydrogen-based reducing gas that satisfy the preset requirement H2 + CO = B (where B is a constant). For example, ... Figure 3 As shown, P tot The first correspondence diagram under the conditions of A = 1 atm, A = 2, or A = 5. (From...) Figure 3 It can be seen that when P tot =1 atm, in any Under the condition of (A = 2 (left) or 5 (right)), as T 重整 As T increases, the conversion rate of CH4 shows a continuous increasing trend. Furthermore, if T... 重整 Below 800℃, although the equilibrium gas composition can meet the requirements for preparing hydrogen-based reducing gas... (e.g., A=2) requires that the effective content of the equilibrium gas composition cannot meet the requirement of reducing gas H2+CO=B (e.g., H2+CO≥92%). Therefore, in order to ensure Both the combined amount of hydrogen-based reducing gas (H2 + CO = B) and the total amount of hydrogen-based reducing gas simultaneously meet the composition requirements of the hydrogen-based reducing gas, under the total system pressure P. tot =1 atm condition T 重整 It must be above 800℃.

[0135] Example 3:

[0136] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation includes:

[0137] a. Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and find that the degrees of freedom are 3;

[0138] b. Select the total pressure P tot Reforming temperature T 重整 And given that the H2 / COmol ratio = A is a physical quantity parameter, the equilibrium gas phase composition function is:

[0139] c. Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. Presuppose that the raw material gas system contains only CH4, H2O, and CO2. In the HCO2 graph, determine the corresponding coordinates of pure CH4, pure CO, and pure CO2 as points (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O + CH4 > 0 and CO2 = 0, draw the L1 line in the HCO2 graph. Using the formulas CO2 + CH4 > 0 and H2O = 0, draw the L2 line in the HCO2 graph. Based on the equal molar ratio between H2O and CH4, draw radial lines passing through point (2, 0) in the HCO2 graph to create an H2O / CH4 scale. Finally, draw a line parallel to the L1 line in the HCO2 graph to create a CO2 / CH4 scale.

[0140] d. The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained, including the above formulas (1) to (9).

[0141] e. At the preset reforming temperature T 重整 ,different Under given conditions, a second critical carbon deposition curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon deposition point. The second critical carbon deposition curve is used to characterize the total pressure P of different systems. tot ,different The coordinates of the critical carbon precipitation point in the two-dimensional HCO3-D diagram under the given conditions;

[0142] f. Determine the preset reforming temperature T based on the second critical carbon deposition curve. 重整 , Under given conditions, the total pressure P of different systems in the process system for preparing hydrogen-based reducing gas under equilibrium conditions. tot The second correspondence between the equilibrium gas mol fractions of each component;

[0143] g. Determine the preset reforming temperature T based on the second correspondence. 重整 , Under given conditions, determine the total system pressure parameters for the hydrogen-based reducing gas preparation system when H2 + CO = B meets the preset requirement. For example, ... Figure 4 As shown, this is for A=2, T 重整 Under conditions of 600℃ (left) or 900℃ (right), the total pressure P of the system tot The second correspondence diagram between the equilibrium gas mol fractions of each component and the given values. Figure 4 It can be seen that, with the total system pressure Ptot As the concentration of ions increases, the conversion rate of CH4 decreases.

[0144] H. Determine the preset reforming temperature T based on the second correspondence. 重整 , Under given conditions, the total pressure P of the system tot The third correspondence with the combined amount of hydrogen-based reducing gas in the equilibrium system, H2 + CO = B. For example, as... Figure 5 As shown, this is for A=2, T 重整 Under conditions of 600℃ (left) or 900℃ (right), the total pressure P of the system tot The third correspondence diagram with the combined amount of hydrogen-based reducing gas H2 + CO = B. (From...) Figure 5 It can be seen that if the total pressure of the system P tot If the concentration is too high, it will be impossible to achieve the requirement that the hydrogen-based reducing gas content (H2+CO=B) be greater than 92%.

[0145] Example 4:

[0146] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation includes:

[0147] a. Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and find that the degrees of freedom are 3;

[0148] b. Select the total pressure P tot Reforming temperature T 重整 And given that the H2 / COmol ratio = A is a physical quantity parameter, the equilibrium gas phase composition function is:

[0149] c. Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. Presuppose that the raw material gas system contains only CH4, H2O, and CO2. In the HCO2 graph, determine the corresponding coordinates of pure CH4, pure CO, and pure CO2 as points (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O + CH4 > 0 and CO2 = 0, draw the L1 line in the HCO2 graph. Using the formulas CO2 + CH4 > 0 and H2O = 0, draw the L2 line in the HCO2 graph. Based on the equal molar ratio between H2O and CH4, draw radial lines passing through point (2, 0) in the HCO2 graph to create an H2O / CH4 scale. Finally, draw a line parallel to the L1 line in the HCO2 graph to create a CO2 / CH4 scale.

[0150] d. The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained, including the above formulas (1) to (9).

[0151] e. Under the preset total system pressure P tot =1 atm Under given conditions, the first critical carbon precipitation curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon precipitation point. Based on the first critical carbon precipitation curve, the reforming temperature T for different conditions is determined. 重整 The first correspondence between the equilibrium gas mol fractions of each component;

[0152] f. Determine the total pressure P of the preset system based on the first correspondence relationship. tot =1 atm, different Under given conditions, the reforming temperature T 重整 The fourth correspondence between the effective components of the reducing gas H2 + CO = B, and the determination of the total system pressure P based on the fourth correspondence. tot , The reforming temperature parameters for preparing hydrogen-based reducing gas under the specified conditions, where H₂ + CO = B. For example, ... Figure 6 As shown, P tot =1 atm, A=2 (left) or 5 (right), reforming temperature T 重整 The fourth correspondence diagram with the combined amount of hydrogen-based reducing gas H2 + CO = B. (From...) Figure 6 It can be seen that when P tot When A = 1 atm and A = 2, in order to obtain a hydrogen-rich reducing gas with a hydrogen-based reducing gas content (H2 + CO = B) greater than 92%, the reforming temperature T is [not specified]. 重整 The temperature must be above 800℃; additionally, increasing the A value helps increase the content of effective components in the reducing gas, but if the reforming temperature T... 重整 If the amount is too low, it will not meet the requirements of the hydrogen-based reducing gas content for the reducing gas preparation process system.

[0153] Example 5:

[0154] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation includes:

[0155] a. Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and find that the degrees of freedom are 3;

[0156] b. Select the total pressure P tot Reforming temperature T 重整 And given that the H2 / COmol ratio = A is a physical quantity parameter, the equilibrium gas phase composition function is:

[0157] c. Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. Presuppose that the raw material gas system contains only CH4, H2O, and CO2. In the HCO2 graph, determine the corresponding coordinates of pure CH4, pure CO, and pure CO2 as points (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O + CH4 > 0 and CO2 = 0, draw the L1 line in the HCO2 graph. Using the formulas CO2 + CH4 > 0 and H2O = 0, draw the L2 line in the HCO2 graph. Based on the equal molar ratio between H2O and CH4, draw radial lines passing through point (2, 0) in the HCO2 graph to create an H2O / CH4 scale. Finally, draw a line parallel to the L1 line in the HCO2 graph to create a CO2 / CH4 scale.

[0158] d. The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained, including the above formulas (1) to (9).

[0159] e. Under the preset total system pressure P tot =1 atm Under given conditions, the first critical carbon precipitation curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon precipitation point. Based on the first critical carbon precipitation curve, the reforming temperature T for different conditions is determined. 重整 The first correspondence between the equilibrium gas mol fractions of each component;

[0160] f. Determine the total pressure P of the preset system based on the first correspondence relationship. tot Preset reforming temperature T 重整 Under the given conditions, The fifth correspondence with the equilibrium gas phase composition is used to determine the total pressure P of the preset system. tot , The reforming temperature parameters for preparing hydrogen-based reducing gas under the specified conditions, where H₂ + CO = B. For example, ... Figure 7 As shown, P tot =1 atm, T 重整 The fifth correspondence diagram under conditions of 600℃ (left) or 900℃ (right). (From...) Figure 7 It can be seen that when P tot =1 atm, T 重整 At 600℃, even if A is increased to 8.0, the amount of hydrogen-based reducing gas still cannot meet the requirement that H2 + CO = B is greater than 92%; when P tot =1 atm, T 重整At 900℃, the amount of hydrogen-based reducing gas corresponding to almost all A values ​​can meet the requirements. Therefore, temperature control for preparing hydrogen-based reducing gas is a more important process parameter than A value.

[0161] Example 6:

[0162] A method for determining process parameters in a hydrogen-based reducing gas preparation process based on controlled carbon precipitation includes:

[0163] a. Calculate the degrees of freedom of the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions, and find that the degrees of freedom are 3;

[0164] b. Select the total pressure P tot Reforming temperature T 重整 And given that the H2 / COmol ratio = A is a physical quantity parameter, the equilibrium gas phase composition function is:

[0165] c. Draw a two-dimensional HCO2 graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. Presuppose that the raw material gas system contains only CH4, H2O, and CO2. In the HCO2 graph, determine the corresponding coordinates of pure CH4, pure CO, and pure CO2 as points (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O + CH4 > 0 and CO2 = 0, draw the L1 line in the HCO2 graph. Using the formulas CO2 + CH4 > 0 and H2O = 0, draw the L2 line in the HCO2 graph. Based on the equal molar ratio between H2O and CH4, draw radial lines passing through point (2, 0) in the HCO2 graph to create an H2O / CH4 scale. Finally, draw a line parallel to the L1 line in the HCO2 graph to create a CO2 / CH4 scale.

[0166] d. The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas process system are characterized by the equilibrium gas phase composition function, and the calculation formula for drawing the critical carbon precipitation point in the two-dimensional HCO diagram is obtained, including the above formulas (1) to (9).

[0167] e. At the preset reforming temperature T 重整 ,different Under given conditions, the second critical carbon precipitation curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon precipitation point, as follows: Figure 8 As shown, the second critical carbon deposition curve is used to characterize the total pressure P of different systems. tot ,different The coordinates of the critical carbon precipitation point in the two-dimensional HCO3-D diagram under the given conditions;

[0168] f. Determine the optimal reforming temperature T using the second critical carbon deposition curve. 重整 Total pressure P of different systems tot ,different The variation law of carbon precipitation in the hydrogen-based reducing gas preparation process under the specified conditions is used to determine the process parameters of the hydrogen-based reducing gas preparation process system. For example, as... Figure 8 As shown, the total pressure P of different systems is... tot Second critical carbon deposition curves under different A values ​​(A = 2, 5) at (1 atm, 10 atm, 20 atm). Figure 8 It can be seen that for low values ​​of A (e.g., A = 2), the total system pressure P increases with increasing pressure. tot The carbon deposition region increases with increasing A value, but for high A values ​​(e.g., A = 5), the carbon deposition region increases with increasing total system pressure P. tot The increase in pressure reduces the carbon deposition region. Calculations show that when A = 3.0, the total system pressure P... tot The increase in carbon deposition has virtually no impact on the increase or decrease of carbon deposition zones.

[0169] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that within the spirit and principles of the present invention, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the corresponding technical solutions to depart from the protection scope of the present invention.

Claims

1. A method for determining process parameters in a process for preparing hydrogen-based reducing gas based on controlled carbon evolution, characterized in that, include: The degrees of freedom of the process system for preparing hydrogen-based reducing gas under critical carbon evolution equilibrium conditions were calculated, and the degree of freedom was found to be 3. Based on the degrees of freedom under the critical carbon deposition equilibrium condition, the independently variable and intensive physical parameters in the process system for preparing hydrogen-based reducing gas are determined to obtain the equilibrium gas phase composition function under the critical carbon deposition equilibrium condition; wherein, the determination of the independently variable and intensive physical parameters in the process system for preparing hydrogen-based reducing gas based on the degrees of freedom under the critical carbon deposition equilibrium condition to obtain the equilibrium gas phase composition function under the critical carbon deposition equilibrium condition includes: selecting the total pressure of the system Reforming temperature Given that the H2 / COmol ratio is the physical quantity parameter, the equilibrium gas phase composition function is: ; Plot a two-dimensional HCO3-Phase graph with the molar ratio between H and C as the ordinate and the molar ratio between O and C as the abscissa. The equilibrium gas phase composition function is used to characterize the O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation process system, respectively, to obtain the calculation formula for plotting the critical carbon precipitation point in the HCO two-dimensional diagram; wherein, the step of using the equilibrium gas phase composition function to characterize the O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation process system to obtain the calculation formula for plotting the critical carbon precipitation point in the HCO two-dimensional diagram includes: using the mol fractions of the components CO, H2O, CO2, H2, and CH4 in the hydrogen-based reducing gas preparation process system respectively... , , , and To represent; The O / C mol ratio and H / C mol ratio in the hydrogen-based reducing gas preparation system are characterized using the equilibrium gas phase composition function as follows: (1)； (2)； in, The total system pressure is expressed in atm. The reforming temperature is expressed in °C. The physical quantity parameters are assigned values, and based on the assigned physical quantity parameters, a critical carbon precipitation curve is plotted on the HCO two-dimensional graph according to the calculation formula for plotting the critical carbon precipitation point. The process parameters for the hydrogen-based reducing gas preparation process that control carbon precipitation are determined based on the critical carbon precipitation curve.

2. The method according to claim 1, characterized in that, The degrees of freedom for calculating the hydrogen-based reducing gas preparation process system under critical carbon evolution equilibrium conditions are 3, including: When the hydrogen-based reducing gas preparation process system is under critical carbon evolution equilibrium conditions, it is determined that the hydrogen-based reducing gas preparation process system contains six material components: gaseous CH4, CO2, CO, H2O, H2, and solid C; the degrees of freedom of the hydrogen-based reducing gas preparation process system are calculated according to the phase rule expression, including: The phase law expression is: in, The number of species present in the process system for preparing hydrogen-based reducing gas. ; The number of independent reactions in the process system for preparing hydrogen-based reducing gas. ; The number of phases in the process system for preparing hydrogen-based reducing gas is given. ; The degrees of freedom of the process system for preparing hydrogen-based reducing gas were calculated. .

3. The method according to claim 1, characterized in that, The method further includes: The system of raw material gases contains only three gases: CH4, H2O, and CO2. In the two-dimensional HCO diagram, the corresponding coordinates of pure CH4 gas, pure CO gas, and pure CO2 gas are determined to be (0, 4), (1, 0), and (2, 0), respectively. Using the formulas H2O+CH4>0 and CO2=0, draw the L1 line in the two-dimensional HCO diagram; using the formulas CO2+CH4>0 and H2O=0, draw the L2 line in the two-dimensional HCO diagram. Based on the molar ratio between H2O and CH4, draw radial straight lines through the point (2, 0) in the HCO two-dimensional diagram to plot the H2O / CH4 scale. Draw a straight line parallel to line L1 in the HCO 2D diagram to plot the CO2 / CH4 scale.

4. The method according to claim 1, characterized in that, The calculation formula for plotting the critical carbon precipitation point in the HCO two-dimensional diagram also includes the calculation formula for the equilibrium gas composition within the hydrogen-based reducing gas preparation process system; the method further includes: Calculate the molar fraction of substances in the hydrogen-based reducing gas preparation process system based on three independent reactions under equilibrium conditions. The relationship with the equilibrium constant specifically includes: According to reaction 1: get ; According to reaction 2: get ; According to reaction 3: get ; Based on the above equilibrium constant calculation formula, the mol fractions of CO2, H2O, and H2 are as follows: (3)； (4)； (5)； Based on the fact that the mol fractions of the equilibrium gases of each component in the hydrogen-based reducing gas preparation process system are summed to 1, we obtain: (6)； Meanwhile, the following preset conditions are configured for the process system for preparing hydrogen-based reducing gas: (7)； (8)； (9)； Equations (3) to (9) above are the calculation formulas for the equilibrium gas composition in the process system for preparing hydrogen-based reducing gas; in, a c This represents the activity of carbon in its pure state, with a value of 1. The preset total system pressure is expressed in atm. This is the preset system reforming temperature, in °C.

5. The method according to claim 1, characterized in that, The process of assigning values ​​to the physical quantity parameters, plotting a critical carbon deposition curve on the HCO2 two-dimensional graph based on the calculated formula for the critical carbon deposition point according to the assigned physical quantity parameters, and determining the process parameters for the hydrogen-based reducing gas preparation process to control carbon deposition based on the critical carbon deposition curve includes: Preset constant pressure , Under given conditions, a first critical carbon deposition curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon deposition point. The first critical carbon deposition curve is used to characterize different reforming temperatures. The coordinates of the lower critical carbon precipitation point in the two-dimensional HCO3-D diagram; Using the first critical carbon evolution curve in conjunction with H2O / CH4 and CO2 / CH4 scales, the constant pressure was determined. , Reforming temperature The ideal water-to-carbon ratio for controlling carbon precipitation under the corresponding conditions ( That is, to determine the process parameters for the preparation of hydrogen-based reducing gas to control carbon precipitation.

6. The method according to claim 5, characterized in that, The method further includes: Preset constant pressure , Under given conditions, different reforming temperatures are determined based on the first critical carbon deposition curve. The first correspondence between the equilibrium gas mol fractions of each component; Based on the first correspondence, a preset constant pressure is determined. , Under given conditions, the process for preparing hydrogen-based reducing gas meets the preset requirements. The reforming temperature parameters at that time.

7. The method according to claim 1, characterized in that, The method further includes: At the preset reforming temperature ,different Under given conditions, a second critical carbon deposition curve is plotted on the HCO2 two-dimensional graph according to the calculation formula for the critical carbon deposition point. The second critical carbon deposition curve is used to characterize the total pressure of different systems. ,different The coordinates of the critical carbon deposition point under the given conditions in the two-dimensional HCO3-D diagram; Based on the second critical carbon deposition curve, the preset reforming temperature is determined. , Under given conditions, the total pressure of different systems in the hydrogen-based reducing gas preparation process system under equilibrium conditions. The second correspondence between the equilibrium gas mol fractions of each component; Based on the second correspondence, the preset reforming temperature is determined. , Under given conditions, the process system for preparing hydrogen-based reducing gas meets the preset requirements. The total pressure parameters of the system at that time.

8. The method according to claim 7, characterized in that, The method further includes: The second critical carbon deposition curve was used to determine the temperature at the preset reforming temperature. Total pressure of different systems ,different The variation law of carbon precipitation under the conditions described in the hydrogen-based reducing gas preparation process is used to determine the process parameters of the hydrogen-based reducing gas preparation process system.

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