A rectifying tower, a rectifying tower control method, device and computer equipment

Abstract

The present application relates to the technical field of chemical production, in particular to a rectifying tower, a rectifying tower control method, a device and computer equipment, wherein the rectifying tower control method comprises the following steps: obtaining the unit power energy price, the average vaporization latent heat of the material in the tower, the target mass fraction of the light component in the tower top product, the mass fraction of the light component in the rectifying tower feed, the tower top product price, the tower bottom product price, a function relationship and a preset formula to calculate the target mass fraction of the light component in the tower bottom product; and controlling the rectifying tower according to the target mass fraction of the light component in the tower bottom product to make the actual mass fraction of the light component in the tower bottom product reach the target mass fraction of the light component in the tower bottom product.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production, and in particular to a distillation tower, a distillation tower control method and device, and computer equipment. Background Art

[0002] Distillation is a mass transfer process widely used in numerous production processes, including petroleum and chemical industries. It separates the components of a mixture to achieve a specified purity. The separation mechanism utilizes the different volatilities (boiling points) of the components in the mixture to allow the light components (low boiling points) in the liquid phase to transfer to the heavy components (high boiling points) in the vapor phase, thereby achieving separation.

[0003] A distillation tower is a multivariable process with multiple inputs and outputs. Its complex internal mechanisms, slow dynamic response, and interdependent variables place high demands on control precision. Furthermore, from an energy perspective, the distillation tower consumes the most energy in a typical three-transmission, one-reaction unit operation. Therefore, minimizing operating costs while ensuring product quality is a crucial issue. Summary of the Invention

[0004] In view of this, the present invention provides a distillation tower, a distillation tower control method, a device and a computer equipment to reduce the operating cost of the distillation tower.

[0005] In the first aspect, the present invention provides a distillation tower control method, comprising the following steps: obtaining a functional relationship between a vaporization ratio and a separation factor; wherein the vaporization ratio is equal to the ratio of the amount of material vaporized in the tower bottom to the amount of feed to the distillation tower; obtaining the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the mass fraction of the light component required in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, and the unit price of the bottom product; calculating the target mass fraction of the light component in the bottom product based on the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, the functional relationship and a preset formula; controlling the distillation tower based on the target mass fraction of the light component in the bottom product so that the actual mass fraction of the light component in the bottom product reaches the target mass fraction of the light component in the bottom product.

[0006] This embodiment provides a distillation tower control method, which obtains other quantities in a preset formula except the mass fraction of the light component in the bottom product, calculates the target mass fraction of the light component in the bottom product when the cost function is lowest according to the preset formula, and further controls the distillation tower according to the target mass fraction of the light component in the bottom product, and ensures that the actual mass fraction of the light component in the bottom product reaches the target mass fraction of the light component in the bottom product, so that the cost of the distillation tower is minimized.

[0007] In an optional embodiment, obtaining the functional relationship between the vaporization ratio and the separation factor includes: obtaining multiple vaporization ratios and mass score groups corresponding to each vaporization ratio, wherein the mass score groups include the actual mass fraction of the light component in the top product and the actual mass fraction of the light component in the bottom product; for any vaporization ratio i, using the mass score group corresponding to the vaporization ratio i to calculate the separation factor corresponding to the vaporization ratio i; traversing the multiple vaporization ratios to obtain the separation factor corresponding to each vaporization ratio; and fitting the multiple vaporization ratios and the separation factors corresponding to each vaporization ratio to obtain a functional relationship.

[0008] In this way, the functional relationship between the vaporization ratio and the separation factor can be obtained quickly and accurately.

[0009] In an optional implementation, the preset formula is:

[0010]

[0011] or,

[0012] Where T represents the operating cost of the distillation tower, F represents the feed rate of the distillation tower, and x B Mass fraction of light components in the bottom product, x B0 is the target mass fraction of the light component in the bottom product, g(s) represents the functional relationship between the vaporization ratio and the separation factor, g'(s) represents the derivative of the functional relationship between the vaporization ratio and the separation factor with respect to the separation factor, C represents the unit price of unit power energy, Hv represents the average latent heat of vaporization of the material in the tower, and x D Indicates the mass fraction of light components required in the top product, x F represents the mass fraction of light components in the distillation tower feed, v D Indicates the unit price of the tower top product, v B Indicates the unit price of the tower bottom product.

[0013] This is because, through reasoning, it can be known that the target mass fraction of the light component in the bottom product when the cost function is lowest can be obtained through Formula 1 or Formula 2.

[0014] In an optional embodiment, the target mass fraction of the light component in the bottom product is calculated according to the unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, the functional relationship, and a preset formula. The formula includes: the unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, and the functional relationship. The functional relationship is input into Formula 1, and the mass fraction of the light component in the bottom product is differentiated to obtain Formula 3; the target mass fraction of the light component in the bottom product is obtained according to Formula 3; or; the functional relationship is differentiated with respect to the separation factor to obtain the derivative of the functional relationship; the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, and the derivative of the functional relationship are input into Formula 2 to obtain the target mass fraction of the light component in the bottom product.

[0015] In this way, the target mass fraction of light components in the bottom product of the distillation tower can be obtained to minimize the cost of the distillation tower.

[0016] In an optional embodiment, controlling the distillation tower according to the target mass fraction of the light component in the bottom product includes: using the target mass fraction of the light component in the bottom product as the set value of the bottom mass controller, so that the bottom mass controller stabilizes the actual mass fraction of the light component in the bottom product at the target mass fraction by adjusting the opening of the reboiler heat source valve.

[0017] The mass fraction of light components in the tower bottom product can be accurately controlled by the tower bottom quality controller.

[0018] In the second aspect, the present invention also provides a distillation tower control device, including a first acquisition module, a second acquisition module, a calculation module and a control module; the first acquisition module is used to obtain the functional relationship between the vaporization ratio and the separation factor; wherein the vaporization ratio is equal to the ratio of the amount of material vaporized in the tower bottom to the feed amount of the distillation tower; the second acquisition module is used to obtain the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the mass fraction of the light component required in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, and the unit price of the bottom product; the calculation module is used to calculate the target mass fraction of the light component in the bottom product based on the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, the functional relationship, and a preset formula; the control module is used to control the distillation tower according to the target mass fraction of the light component in the bottom product, so that the actual mass fraction of the light component in the bottom product reaches the target mass fraction of the light component in the bottom product.

[0019] In a third aspect, the present invention further provides a computer device comprising a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the distillation tower control method of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0020] In a fourth aspect, the present invention further provides a distillation tower comprising the computer device of the third aspect.

[0021] In a fifth aspect, the present invention further provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the distillation tower control method of the first aspect or any corresponding embodiment thereof.

[0022] In a sixth aspect, the present invention further provides a computer program product, comprising computer instructions for causing a computer to execute the distillation tower control method of the first aspect or any corresponding embodiment thereof.

[0023] The distillation tower, distillation tower control method, device, and computer equipment of the embodiments of the present invention have the following beneficial effects: By reasoning, it can be known that the target mass fraction of the light component in the bottom product when the cost function is minimized can be obtained by Formula 1 or Formula 2. Based on this, the present embodiment provides a distillation tower control method, which obtains other quantities in Formula 1 or Formula 2 except the mass fraction of the light component in the bottom product, calculates the target mass fraction of the light component in the bottom product when the cost function is minimized according to Formula 1 or Formula 2, and further controls the distillation tower according to the target mass fraction of the light component in the bottom product, so that the actual mass fraction of the light component in the bottom product reaches the target mass fraction of the light component in the bottom product, thereby minimizing the cost of the distillation tower. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] Figure 1 It is a flow chart of a control scheme for a distillation tower in the related art;

[0026] Figure 2 is a flow chart of a distillation column control method according to an embodiment of the present invention;

[0027] Figure 3 is a process of another distillation column control method according to an embodiment of the present invention;

[0028] Figure 4 is a flow chart of an example of a distillation column control method according to an embodiment of the present invention;

[0029] Figure 5 is a structural block diagram of a distillation tower control device according to an embodiment of the present invention;

[0030] Figure 6 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0032] like Figure 1 As shown in the figure, the distillation unit is generally composed of a distillation tower, a reboiler, a condenser, a condensate tank and a reflux pump. Figure 1 In the equation, F represents the feed flow rate of the distillation column, x F represents the mass fraction of light components in the distillation tower feed, B represents the output of the tower bottom product, and x B represents the mass fraction of light components in the bottom product, and D represents the output of the top product; x D Indicates the mass fraction of light components in the tower top product; PC represents the pressure sensor, LC1~LC2 represent the first liquid level sensor to the second liquid level sensor, FC1~FC5 represent the first flow sensor to the fifth flow sensor, and V1~V6 represent the first valve to the sixth valve.

[0033] Taking a binary system as an example, the conventional control scheme uses the temperature of the tower kettle sensitive plate to control the amount of steam added to the reboiler, and the tower kettle liquid level to control the tower kettle extraction amount; the tower top pressure controls the flow of condenser cooling water, the condensate tank liquid level controls the reflux flow, and the tower top extraction is controlled by a constant flow rate.

[0034] The problem with conventional control schemes is that there is a certain degree of control coupling between the tower bottom steam and the tower top condensation. That is, if the tower bottom steam volume is increased near the normal operating point, the tower bottom temperature rises, the vaporization volume increases, and the tower top pressure immediately increases. Under the action of the tower top pressure control loop, the cooling water flow of the tower top condenser increases, and the condensation volume increases, which causes the liquid level in the condensate tank to rise. Under the action of the liquid level control loop, the reflux flow increases, and the temperature and pressure of the distillation tower return to the normal operating point. In this way, the heat in the tower bottom and the cooling capacity at the tower top increase simultaneously, without significantly affecting product quality, but it significantly increases the energy consumption of the distillation tower operation. Many existing units do not know whether the operating point of the operating distillation tower is the optimal working point to meet the separation objectives, resulting in their unfavorable operating costs.

[0035] Based on this, it is very necessary to develop a cost optimization control method for distillation towers.

[0036] For a given binary distillation tower, taking the overhead extraction as the main product as an example, its cost optimization control method can be divided into the following steps:

[0037] 1) Determination of objective function: As a cost optimization control method, the distillation tower cost function can be used as the objective function for research. Generally speaking, the operating cost of a distillation tower can be expressed as:

[0038]

[0039] T—operating cost of distillation column;

[0040] F—distillation column feed amount;

[0041] v D —Unit price of tower top products;

[0042] v B —Unit price of the tower bottom product;

[0043] B—the output of the product from the bottom of the tower;

[0044] x B —Mass fraction of light components in the bottom product;

[0045] C—unit price of energy per unit power;

[0046] V—the amount of material vaporized in the bottom of the tower;

[0047] H v —Average latent heat of vaporization of materials in the tower;

[0048] Where: Bx B Represents the light component content extracted from the bottom of the tower, Represents the value loss of light component products per unit feed amount, and its value is related to the separation capacity of the distillation column; It represents the energy cost per unit of raw material consumption, and its value is related to the operation of the distillation tower;

[0049] 2) Derivation of equilibrium relationship:

[0050] First, taking the distillation tower as a system, we establish the material balance relationship for the inlet and outlet materials and the light components respectively, and we can get:

[0051] F=D+B……Formula 5

[0052] Fx F =Dx D +Bx B ...Formula 6

[0053] Multiply both sides of Formula 5 by x D Subtracting this from Formula 6 yields:

[0054]

[0055] D—tower top product extraction volume;

[0056] x F —Mass fraction of light components in the distillation column feed;

[0057] x D —Mass fraction of light components in the top product;

[0058] The meanings of the remaining symbols are the same as before.

[0059] From the above relationship, we can see that when B / F and x FWhen certain, we can get x D and x B The proportional relationship between them, but it is impossible to D and x B All confirmed.

[0060] Secondly, an energy balance relationship is established for the distillation column system. For ease of expression, the concept of separation factor, a common parameter in the separation process, is introduced here. That is, the degree of separation obtained in any specific separation process can be expressed by the relationship between the product components:

[0061]

[0062] s—separation factor, the meanings of other symbols are the same as before.

[0063] It can be seen from formula 8 that as s increases, x D will increase and x B The separation factor s is affected by many factors, such as average relative volatility, number of theoretical plates, plate efficiency, feed composition, feed position, and the vaporization ratio of the rising steam volume V and feed volume F in the tower. For a given tower, considering only the effect of operating conditions on the separation factor, s can be approximately considered to be related to V / F, that is, the relationship exists:

[0064] s≈f(V / F)……Formula 9

[0065] Formula 9 can also be transformed into:

[0066] V / F ≈ g(s)……Formula 10

[0067] The g(s) relationship can be obtained by fitting the data obtained through the sensitivity analysis module of the process simulation software ASPEN.

[0068] 3) Objective function deformation:

[0069] Substituting Formula 7, Formula 8, and Formula 10 into Formula 4 yields:

[0070]

[0071] 4) Find the extreme value of the objective function:

[0072] In formula 1, x D is a certain value (due to the high quality requirements of the top product, quality control is set to ensure x D Certain), x F Also a certain value, v D 、v B , C is a constant, and the operating pressure remains unchanged. vTherefore, T / F is only the mass fraction of the light component in the bottom product x B To find the extreme value of T / F, we can apply Formula 1 to x B After taking the derivative, just set the derivative equal to 0.

[0073] Apply Formula 1 to x B Taking the derivative and simplifying we get:

[0074]

[0075] make You can get the x value at which the cost function is the smallest. B The relationship between the values:

[0076]

[0077] In the above formula, x B0 x when T / F reaches the minimum value B The value of x that makes the cost function the lowest B value.

[0078] Based on this, an embodiment of the present invention provides an embodiment of a distillation tower control method. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0079] In this embodiment, a distillation tower control method is provided, which can be used in computer equipment. Figure 2 : is a flow chart of a distillation tower control method according to an embodiment of the present invention, such as Figure 2 As shown, the process includes the following steps:

[0080] Step S201: Obtaining a functional relationship between a vaporization ratio and a separation factor s, wherein the vaporization ratio is equal to the ratio of the amount of material V vaporized in the tower bottom to the amount of material fed into the distillation tower F.

[0081] Step S202: Obtain the unit price C of unit power energy, the average latent heat of vaporization Hv of the material in the tower, and the mass fraction x of the light component required in the tower top product. D , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B .

[0082] Step S203: Based on the unit price C of unit power energy, the average latent heat of vaporization Hv of the materials in the tower, and the target mass fraction x of the light component in the tower top product, D0 , the mass fraction of light components in the distillation tower feed xF , the unit price of the tower top product v D 、Unit price of tower kettle products B , functional relationship, and the preset formula to calculate the target mass fraction x of the light component in the bottom product B0 .

[0083] In an optional implementation, the preset formula may be the above-mentioned formula 1 or the above-mentioned formula 2.

[0084] Step S204: According to the target mass fraction x of the light component in the bottom product B0 The distillation tower is controlled so that the actual mass fraction of the light component in the bottom product reaches the target mass fraction x of the light component in the bottom product B0 .

[0085] Through the above reasoning, it can be known that the target mass fraction of the light component in the bottom product when the cost function is lowest can be obtained by formula 1 or formula 2.

[0086] Based on this, this embodiment provides a distillation tower control method, by obtaining other quantities in Formula 1 or Formula 2 except the mass fraction of the light component in the bottom product, and calculating the target mass fraction of the light component in the bottom product when the cost function is lowest according to Formula 1 or Formula 2, the distillation tower is further controlled according to the target mass fraction of the light component in the bottom product, and the actual mass fraction of the light component in the bottom product reaches the target mass fraction of the light component in the bottom product, so that the cost of the distillation tower is minimized.

[0087] In this embodiment, a distillation tower control method is provided, which can be used in computer equipment. Figure 3 is a flow chart of another distillation tower control method according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0088] Step S301: Obtaining a functional relationship between a vaporization ratio and a separation factor s; wherein the vaporization ratio is equal to the ratio of the amount of material V vaporized in the tower bottom to the amount of material fed into the distillation tower F.

[0089] In an optional embodiment, obtaining the functional relationship between the vaporization ratio and the separation factor s includes the following steps:

[0090] Step S3011: Obtain multiple vaporization ratios and mass fraction groups corresponding to each vaporization ratio, wherein the mass fraction group includes the actual mass fraction x of the light component in the top product. D1 The actual mass fraction of light components in the bottom product x B1 .

[0091] Specifically, a plurality of vaporization ratios and a mass fraction group corresponding to each vaporization ratio can be obtained according to the ASPEN model of the distillation tower.

[0092] Step S3012: for any vaporization ratio i, use the mass fraction group corresponding to the vaporization ratio i to calculate the separation factor corresponding to the vaporization ratio i; traverse multiple vaporization ratios to obtain the separation factor corresponding to each vaporization ratio.

[0093] Step S3013: Fitting multiple vaporization ratios and the separation factors corresponding to each vaporization ratio to obtain a functional relationship.

[0094] Specifically, Matlab software can be used for fitting to obtain the functional relationship between the vaporization ratio and the separation factor s.

[0095] Step S302: Obtain the unit price C of unit power energy, the average latent heat of vaporization Hv of the material in the tower, and the mass fraction x of the light component required in the tower top product. D , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B .

[0096] Step S303: Based on the unit price C of unit power energy, the average latent heat of vaporization Hv of the materials in the tower, and the target mass fraction x of the light component in the tower top product, D0 , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B , functional relationship, and the preset formula to calculate the target mass fraction x of the light component in the bottom product B0 .

[0097] Among them, the target mass fraction of light components in the bottom product is x B0 That is, the mass fraction of light components in the bottom product when T / F reaches the minimum value.

[0098] In an optional embodiment, according to the unit price C of unit power energy, the average latent heat of vaporization Hv of the material in the tower, the target mass fraction x of the light component in the tower top product, D0 , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B , functional relationship, and the preset formula to calculate the target mass fraction x of the light component in the bottom product B0 include:

[0099] Step a1: Differentiate the functional relationship with respect to the separation factor to obtain the derivative of the functional relationship.

[0100] Step a2: The unit price of unit power energy C, the average latent heat of vaporization Hv of the material in the tower, and the target mass fraction of light components in the tower top product x D0 , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B The derivative of the function relationship is input into Formula 2 to obtain the target mass fraction x of the light component in the bottom product. B0 .

[0101] In another optional embodiment, according to the unit price C of unit power energy, the average latent heat of vaporization Hv of the material in the tower, the target mass fraction x of the light component in the tower top product, D0 , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B , functional relationship, and the preset formula to calculate the target mass fraction x of the light component in the bottom product B0 include:

[0102] Step b1: The unit price of unit power energy C, the average latent heat of vaporization Hv of the material in the tower, the target mass fraction of light components in the tower top product x D0 , the mass fraction of light components in the distillation tower feed x F , the unit price of the tower top product v D 、Unit price of tower kettle products B , and the functional relationship is input into formula 1, and the mass fraction of the light component in the bottom product x B Taking the derivative, we get Formula 3.

[0103] Step b2: Obtain the target mass fraction x of the light component in the bottom product according to formula 3 B0 .

[0104] Step S304: According to the target mass fraction x of the light component in the bottom product B0 The distillation tower is controlled so that the actual mass fraction of the light component in the bottom product reaches the target mass fraction x of the light component in the bottom product B0 .

[0105] In an optional embodiment, according to the target mass fraction x of the light component in the bottom product B0 Controlling the distillation tower includes: setting the target mass fraction of the light component in the bottom product to x B0As the set value of the tower kettle quality controller, the tower kettle quality controller can stabilize the actual mass fraction of the light component in the tower kettle product at the target mass fraction x by adjusting the opening of the reboiler heat source valve. B0 .

[0106] That is to say, a distillation tower cost optimization control method can be based on Figure 4 Method implementation. Figure 4 In the equation, F represents the feed flow rate of the distillation column, x F represents the mass fraction of light components in the distillation tower feed, B represents the output of the tower bottom product, and x B represents the mass fraction of light components in the bottom product, and D represents the output of the top product; x D Indicates the mass fraction of light components in the top product; PC represents the pressure sensor, LC1~LC2 represent the first liquid level sensor to the second liquid level sensor, FC1~FC5 represent the first flow sensor to the fifth flow sensor, V1~V6 represent the first valve to the sixth valve, and AC represents the bottom mass controller.

[0107] like Figure 4 As shown, first, based on the ASPEN model of the distillation tower, the sensitivity analysis module is used to derive the mass fraction x of the light component in the tower top product corresponding to different V / F conditions. D and the mass fraction of light components in the bottom product x B The numerical value of .

[0108] Furthermore, select x D For data points that are higher than the product quality requirements, calculate the values ​​of the separation factor s under different V / F conditions.

[0109] Furthermore, Matlab software was used to fit the functional relationship g(s) between V / F and separation factor s.

[0110] Furthermore, a calculation block Y is created in the DCS system.

[0111] Furthermore, Formula 1 or Formula 2 is written into calculation block Y.

[0112] Furthermore, the above functional relationship g(s) is introduced into the calculation block Y.

[0113] Furthermore, the unit price of unit power energy C, the average latent heat of vaporization Hv of the material in the tower, the mass fraction of light components required in the tower top product x D , the mass fraction of light components in the distillation tower feed x F And the unit price of the tower top and tower bottom products v D 、v B Set the input terminal on the DCS screen and introduce calculation block Y with the same parameters.

[0114] Furthermore, we derive x from the computation block Y. B0 The parameter is used as the set value of the tower kettle quality controller AC. The tower kettle quality controller adjusts the opening of the reboiler heat source valve to keep the mass fraction of the light component in the tower kettle product stable at x B0 , thereby achieving the optimization of the cost function while meeting the tower top product index requirements.

[0115] It can be seen that the present invention constructs a cost function for the operation of the distillation tower, and uses mathematical theory to calculate and explore the optimal operating parameters of the distillation tower while meeting product indicators, so as to reduce the operating cost of the distillation tower as much as possible.

[0116] This embodiment provides a distillation tower control method, which obtains other quantities in Formula 1 or Formula 2 except the mass fraction of the light component in the bottom product, calculates the target mass fraction of the light component in the bottom product when the cost function is lowest according to Formula 1 or Formula 2, and further controls the distillation tower according to the target mass fraction of the light component in the bottom product, so that the actual mass fraction of the light component in the bottom product reaches the target mass fraction of the light component in the bottom product, thereby minimizing the cost of the distillation tower.

[0117] In order to illustrate the distillation tower control method according to the embodiment of the present invention in more detail, the implementation process and method of the distillation tower control method will be described below by taking the phenol product tower of the vanillin plant as an example.

[0118] The phenol product tower in the vanillin plant's phenol process is used to separate a phenol-catechol binary mixture at approximately 50°C containing 0.6% phenol (mass fraction). The feed rate is 10,000 kg / h. The top extraction is required to produce a phenol product with a mass fraction of no less than 99%, while the bottom extraction is required to produce a catechol product with a mass fraction of approximately 99%. The tower operates at a pressure of 10 kPaA, with 10 theoretical stages, 5 feed positions, a reflux ratio of 2, and a fixed top extraction rate of 6,000 kg / h. Circulating water is used as the refrigerant for the top condensation process, while hot oil is used as the heat source in the bottom extraction process.

[0119] A model of the phenol product tower was constructed using the chemical process simulation software Aspen. In the sensitivity analysis module, the vaporization rate V in the tower bottom was defined as the manipulated variable, with a range of 15,000 to 25,000 kg / h (the normal value in the model was 19,110 kg / h) and a step size of 1,000 kg / h. The mass fraction of phenol in the tower top and tower bottom effluent streams, x, was defined. D 、x B As two sets of acquisition variables, the data can be exported after running the simulation as follows:

[0120]

[0121] Using Matlab software to fit the relationship between V / F and separation factor s, we can get:

[0122]

[0123] Using Matlab software to differentiate g(s) with respect to s, we can get:

[0124]

[0125] Substituting into Formula 2 and replacing s in Formula 8 yields:

[0126]

[0127] Without considering the energy loss during the heating and operation of the hot oil in the tower kettle reboiler, since the hot oil is heated by an electric heater, according to the industrial electricity price C = 0.8 yuan / kwh, the average vaporization latent heat of phenol and catechol H v =473kJ / kg, the price of the phenol product at the top of the tower is 20,000 yuan / t, the price of the catechol product at the bottom of the tower is 6,000 yuan / t, and the quality fraction requirement of the phenol product taken out from the top of the tower is x D =0.99, the mass fraction of lignin in the feed x F =0.6, solve for x B0 = 0.0129. In the ASPEN model of the phenol product tower, the design specification module is applied to define the mass fraction of phenol in the bottom output x B The target value is set to 0.0129 for the acquisition variable, and the amount of material vaporized in the tower bottom V is the manipulated variable with upper and lower limits of 10000 to 20000 kg / h. After running the simulation, the corresponding V = 16220 kg / h can be obtained. Substituting this V value back into the original model, the x value at this time can be obtained after running the simulation. D =0.9914, which can meet the requirement of 99% mass fraction of phenol product produced from the top of the tower.

[0128] Therefore, theoretically, as long as the tower bottom temperature controller is replaced with a mass controller, the mass fraction of phenol in the catechol product extracted from the tower bottom can be adjusted by adjusting the opening of the reboiler hot oil feed valve. B By controlling it at around 0.0129, the operating cost of the phenol product tower can be reduced to the lowest level.

[0129] According to the original control scheme of the device, the amount of material vaporized in the tower bottom is V = 19110 kg / h, and the mass fraction of the lignin product in the tower top is x D =0.9937, the mass fraction of lignin in the bottom of the tower is x B=0.0094. Based on the above data, the normal operating cost of the phenol product tower is calculated according to Formula 7 to be approximately 253.5 yuan / ton. After implementing the distillation tower cost optimization control plan, the normal operating cost of the phenol product tower is recalculated using Formula 7 to be 242.73 yuan / ton. Assuming 8,000 hours of operation per year, this distillation tower alone can save 861,600 yuan in operating expenses per year, significantly reducing the operating cost of the distillation tower.

[0130] This embodiment also provides a distillation column control device for implementing the above-mentioned embodiments and preferred embodiments. Details already described will not be repeated. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented using software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0131] This embodiment provides a distillation tower control device, such as Figure 5 Shown, including:

[0132] The first acquisition module 501 is used to obtain the functional relationship between the vaporization ratio and the separation factor; wherein the vaporization ratio is equal to the ratio of the amount of material vaporized in the tower bottom to the amount of material fed into the distillation tower;

[0133] The second acquisition module 502 is used to obtain the unit price of unit power energy, the average latent heat of vaporization of the materials in the tower, the mass fraction of light components required in the tower top product, the mass fraction of light components in the distillation tower feed, the unit price of the tower top product, and the unit price of the tower bottom product;

[0134] Calculation module 503 is configured to calculate the target mass fraction of light components in the bottom product based on the unit price of unit power energy, the average latent heat of vaporization of the materials in the tower, the target mass fraction of light components in the top product, the mass fraction of light components in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, a functional relationship, and a preset formula;

[0135] The control module 504 is used to control the distillation column according to the target mass fraction of the light components in the bottom product, so that the actual mass fraction of the light components in the bottom product reaches the target mass fraction of the light components in the bottom product.

[0136] In some optional embodiments, the first acquisition module 501 is specifically used to: obtain multiple vaporization ratios and mass score groups corresponding to each vaporization ratio, wherein the mass score groups include the actual mass fraction of the light component in the top product and the actual mass fraction of the light component in the bottom product; for any vaporization ratio i, use the mass score group corresponding to the vaporization ratio i to calculate the separation factor corresponding to the vaporization ratio i; traverse multiple vaporization ratios to obtain the separation factor corresponding to each vaporization ratio; fit the multiple vaporization ratios and the separation factors corresponding to each vaporization ratio to obtain a functional relationship.

[0137] In some optional implementations, the preset formula is:

[0138]

[0139] or,

[0140] Among them, C represents the unit price of unit power energy, Hv represents the average latent heat of vaporization of the material in the tower, and x D Indicates the mass fraction of light components required in the top product, x F represents the mass fraction of light components in the distillation tower feed, v D Indicates the unit price of the tower top product, v B Indicates the unit price of the tower bottom product.

[0141] In some optional embodiments, the calculation module 503 is specifically used to: input the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product and the functional relationship into Formula 1, and derive the mass fraction of the light component in the bottom product to obtain Formula 3; and obtain the target mass fraction of the light component in the bottom product according to Formula 3.

[0142] In some optional embodiments, the calculation module 503 is specifically used to: differentiate the functional relationship with respect to the separation factor to obtain the derivative of the functional relationship; input the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, and the derivative of the functional relationship into Formula 2 to obtain the target mass fraction of the light component in the bottom product.

[0143] In some optional embodiments, the control module 504 is specifically used to: use the target mass fraction of the light component in the bottom product as the set value of the bottom quality controller, so that the bottom quality controller stabilizes the actual mass fraction of the light component in the bottom product at the target mass fraction by adjusting the opening of the reboiler heat source valve.

[0144] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0145] The distillation tower control device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0146] The embodiment of the present invention also provides a computer device having the above Figure 5 The distillation column control device is shown.

[0147] An embodiment of the present invention further provides a distillation tower comprising the above-mentioned computer device.

[0148] See also Figure 6 , Figure 6 is a structural diagram of a computer device provided by an optional embodiment of the present invention, such as Figure 6 As shown, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in the memory or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Equally, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 6 A processor 10 is taken as an example.

[0149] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0150] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0151] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0152] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0153] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Figure 6 The bus connection is taken as an example.

[0154] The input device 30 can receive input digital or character information and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touch pad, an indicator stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display, and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0155] The embodiment of the present invention also provides a computer-readable storage medium. The above-mentioned method according to the embodiment of the present invention can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0156] A portion of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the form in which the computer program instruction exists in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc. Accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium that can be accessed by the computer.

[0157] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A distillation tower control method, characterized in that: include: Obtain the functional relationship between vaporization ratio and separation factor; The vaporization ratio is equal to the ratio of the amount of material vaporized from the tower bottom to the amount of material fed into the distillation tower; Obtain the unit price of unit power energy, the average latent heat of vaporization of the materials in the tower, the mass fraction of light components required in the tower top product, the mass fraction of light components in the distillation tower feed, the unit price of the tower top product, and the unit price of the tower bottom product; The target mass fraction of the light component in the bottom product is calculated based on the unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, the functional relationship, and a preset formula; The preset formula is: or, Wherein, T represents the operating cost of the distillation tower, F represents the feed rate of the distillation tower, and x B represents the mass fraction of light components in the bottom product, x B0 is the target mass fraction of the light component in the bottom product, g(s) represents the functional relationship between the vaporization ratio and the separation factor, g'(s) represents the derivative of the functional relationship between the vaporization ratio and the separation factor with respect to the separation factor, C represents the unit price of the unit power energy, Hv represents the average latent heat of vaporization of the material in the tower, x D represents the mass fraction of the light component required in the top product, x F represents the mass fraction of light components in the distillation column feed, v D represents the unit price of the tower top product, v B Indicates the unit price of the tower bottom product; The distillation tower is controlled according to the target mass fraction of the light components in the bottom product so that the actual mass fraction of the light components in the bottom product reaches the target mass fraction of the light components in the bottom product, thereby minimizing the operating cost of the distillation tower.

2. The method according to claim 1, characterized in that The functional relationship between the vaporization ratio and the separation factor is obtained as follows: Acquire a plurality of vaporization ratios and a mass score group corresponding to each vaporization ratio, wherein the mass score group includes an actual mass fraction of the light component in the tower top product and an actual mass fraction of the light component in the tower bottom product; For any vaporization ratio i, using the mass fraction group corresponding to the vaporization ratio i, calculate the separation factor corresponding to the vaporization ratio i; traverse the plurality of vaporization ratios to obtain the separation factor corresponding to each vaporization ratio; The plurality of vaporization ratios and the separation factor corresponding to each vaporization ratio are fitted to obtain the functional relationship.

3. The method according to claim 1, characterized in that The target mass fraction of the light component in the bottom product is calculated based on the unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, the functional relationship, and a preset formula, including: The unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the tower top product, the mass fraction of the light component in the distillation tower feed, the unit price of the tower top product, the unit price of the tower bottom product, and the functional relationship are input into Formula 1, and the mass fraction of the light component in the tower bottom product is derived to obtain Formula 3; Obtain the target mass fraction of the light component in the bottom product according to Formula 3; or; Derivative the functional relationship with respect to the separation factor to obtain a derivative of the functional relationship; The unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, and the derivative of the functional relationship are input into Formula 2 to obtain the target mass fraction of the light component in the bottom product.

4. The method according to claim 1, wherein Controlling the distillation tower according to the target mass fraction of the light component in the bottom product includes: The target mass fraction of the light component in the bottom product is used as the set value of the bottom quality controller, so that the bottom quality controller stabilizes the actual mass fraction of the light component in the bottom product at the target mass fraction by adjusting the opening of the reboiler heat source valve.

5. A distillation tower control device, characterized in that: include: A first acquisition module is used to obtain a functional relationship between a vaporization ratio and a separation factor; wherein the vaporization ratio is equal to the ratio of the amount of material vaporized in the tower bottom to the amount of material fed into the distillation tower; The second acquisition module is used to obtain the unit price of unit power energy, the average latent heat of vaporization of the material in the tower, the mass fraction of light components required in the tower top product, the mass fraction of light components in the distillation tower feed, the unit price of the tower top product, and the unit price of the tower bottom product; a calculation module, configured to calculate the target mass fraction of the light component in the bottom product based on the unit price of the unit power energy, the average latent heat of vaporization of the material in the tower, the target mass fraction of the light component in the top product, the mass fraction of the light component in the distillation tower feed, the unit price of the top product, the unit price of the bottom product, the functional relationship, and a preset formula; The preset formula is: or, Wherein, T represents the operating cost of the distillation tower, F represents the feed rate of the distillation tower, and x B represents the mass fraction of light components in the bottom product, x B0 is the target mass fraction of the light component in the bottom product, g(s) represents the functional relationship between the vaporization ratio and the separation factor, g'(s) represents the derivative of the functional relationship between the vaporization ratio and the separation factor with respect to the separation factor, C represents the unit price of the unit power energy, Hv represents the average latent heat of vaporization of the material in the tower, x D represents the mass fraction of the light component required in the top product, x F represents the mass fraction of light components in the distillation column feed, v D represents the unit price of the tower top product, v B Indicates the unit price of the tower bottom product; A control module is used to control the distillation tower according to the target mass fraction of the light components in the bottom product, so that the actual mass fraction of the light components in the bottom product reaches the target mass fraction of the light components in the bottom product, thereby minimizing the operating cost of the distillation tower.

6. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the distillation column control method according to any one of claims 1 to 4 by executing the computer instructions.

7. A distillation tower, characterized in that: A computer device comprising the computer device of claim 6.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the distillation column control method according to any one of claims 1 to 4.

9. A computer program product, characterized in that The method comprises computer instructions for causing a computer to execute the distillation column control method according to any one of claims 1 to 4.

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