Coal-fired power plant wastewater treatment method, device and electronic equipment

Abstract

The present invention provides a method, device, and electronic equipment for treating coal-fired power plant wastewater, relating to the field of traditional energy technology. The method comprises: establishing a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression equipment; establishing a reverse osmosis mechanism model based on the reverse osmosis equipment; establishing a joint mechanism model based on the connection method between the reverse osmosis equipment and the mechanical steam compression equipment; establishing a joint treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the joint mechanism model; and obtaining a target operation plan based on the joint treatment equipment cost calculation model and the constraint conditions of the joint treatment equipment. The present invention reduces the operating cost of the entire joint treatment equipment by using the high-concentration and high-temperature brine produced by high-pressure coil reverse osmosis as the feed water for mechanical steam compression evaporation, thereby obtaining the lowest-cost coal-fired power plant wastewater treatment plan.

Description

Technical Field

[0001] The present invention relates to the field of traditional energy technology, and in particular to a method for treating coal power plant wastewater, a coal power plant wastewater treatment device, an electronic device and a computer-readable storage medium. Background Art

[0002] At the same time, with the significant increase in global energy consumption, coal-fired power plants have been widely used to meet the growing demand for electricity. Therefore, it is very important to treat the large amount of coal-fired power wastewater generated in the process of coal-fired power plants.

[0003] Compared with common seawater, coal-fired power plant wastewater has higher pH and COD, more complex water quality, and is more difficult to treat and reuse.

[0004] Currently, reverse osmosis (RO) plays a key role in the treatment of saline wastewater due to its high efficiency, ease of operation, and ability to maintain biological activity. Reverse osmosis, also known as reverse osmosis, uses pressure as the driving force to separate freshwater and salt from saline wastewater via a reverse osmosis (RO) membrane. Under natural conditions, the solvent in a less concentrated solution automatically diffuses through a semipermeable membrane into the more concentrated solution, eventually reaching osmotic equilibrium and establishing an osmotic pressure. If a pressure greater than the osmotic pressure is applied to one side of the concentrated solution, the solution, driven by this pressure, continues to permeate the solvent to the other side. This process, called reverse osmosis, ultimately produces more freshwater and a higher concentration of concentrated brine.

[0005] However, the direct discharge of higher concentration brine will not only cause environmental pollution but also waste water resources. Summary of the Invention

[0006] The purpose of the present invention is to provide a method, device and electronic equipment for treating coal-fired power plant wastewater. The present invention constructs a combined treatment device based on the principles of high-pressure spiral reverse osmosis and mechanical vapor recompression evaporation of coal-fired power plant wastewater. By using the high-concentration and high-temperature concentrated brine produced by high-pressure spiral reverse osmosis as the feed water for mechanical vapor compression evaporation, the operating cost of the entire combined treatment device is reduced, thereby obtaining the lowest-cost coal-fired power plant wastewater treatment solution.

[0007] To achieve the above objectives, an embodiment of the present invention provides a method for treating coal-fired power plant wastewater, which is applied to a combined treatment device, wherein the combined treatment device includes a reverse osmosis device and a mechanical vapor compression device. The reverse osmosis device is used to treat the coal-fired power plant wastewater and obtain concentrated brine, and the mechanical vapor compression device is used to treat the concentrated brine obtained by the reverse osmosis device and obtain a crystallizable saturated salt solution and fresh water. The method includes:

[0008] Establishing a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device;

[0009] Establishing a reverse osmosis mechanism model based on the reverse osmosis equipment, wherein the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment;

[0010] Establishing a joint mechanism model based on the connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize the operating principle of the joint treatment device;

[0011] Establishing a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model;

[0012] A target operation plan is obtained by calculation based on the cost calculation model of the joint processing equipment and the constraint conditions of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time.

[0013] Specifically, the mechanical steam compression equipment includes a heat exchanger, an evaporator, a demister, a variable frequency compressor, and a circulating pump. The mechanical steam variable frequency compression mechanism model is expressed by the following calculation formula:

[0014] M f =M b +M d

[0015] M f X f =M b X b +M d X d

[0016] Q HX_en =M f ·C pf ·(T f -T cw )

[0017] Q HX_ex =M b ·C pb (T b -T0)+M d ·C pd (T d -T0)

[0018] Q HX_en =Q HX_ex

[0019] Q e_in =Md λ d +M d ·C pv (T s -T d )

[0020] Q e_out =M d λ vp +M f ·C pf (T b -T f )

[0021] Q e_in =Q e_out

[0022] T vp =T b -BPE

[0023] BPE=f·Δ0′

[0024]

[0025] Δ0′=69.8×C b 3 -8.15×C b 2 +5.19×C b

[0026] T vp =T v

[0027] ΔT=T d -T b

[0028] Q e =U e ·A e ·LTMD

[0029] U e =1.9695+1.2057×10 -2 ×T b -8.5989×10 -5 ×T b 2 +2.565×10 -7 ×T b 3

[0030]

[0031] H s =2499.15+1.955×T s-1.927×10 -3 ×T s 2

[0032] W fre =(H s -H v )·0.000277·ε / η com

[0033] η v_fre / η v，ref =d1+d2(N / N ref )+d3(N / N ref ) 3

[0034]

[0035]

[0036] d1+d2+d3=1

[0037] e1+e2+e3=1

[0038] N=60f re (1-ss) / p n

[0039] Among them, M d represents the mass flow rate of condensing steam, M b Represents the mass flow rate of concentrated brine, M f represents the feed mass flow rate, X d Indicates the mass percentage concentration of condensed steam, X b Indicates the mass percentage concentration of concentrated brine, X f Indicates the mass percentage concentration of feed water, T f Indicates the temperature after passing through the heat exchanger, T cw Indicates the temperature of feed water, T b Indicates the brine temperature at the evaporator outlet, T d Indicates the temperature of the condensed steam at the evaporator outlet, T b0 Indicates the temperature of the water produced after passing through the heat exchanger, Cp d 、Cp f 、Cp b 、Cp v They represent the specific heat capacity of condensed water, feed water, brine and steam above the demister, Q HX_en , Q HX_ex Respectively represent the heat absorbed and released by the heat exchanger, H s is the enthalpy of the superheated steam after the compressor outlet, H vis the enthalpy of the steam before entering the compressor, d1, d2, d3, e1, e2 and e3 are respectively the conventional coefficients in the mechanical steam variable frequency compression mechanism model, λ vp ,λ d They represent the latent heat below the demister and the latent heat of the steam inside the gate, T s Indicates the temperature of superheated steam, Q e_in , Q e_out Respectively represent the heat generated inside and outside the tube in the evaporator, T vp Indicates the temperature below the demister, T b represents the boiling point temperature of feed water, BPE represents boiling point elevation, f represents correction factor, T v Indicates the temperature above the demister, Q e represents the heat transfer of the evaporator, U e represents the total heat transfer coefficient, ε represents the compression ratio, η com Indicates the efficiency of the variable frequency compressor, N ref 、V suc,ref and η v,ref Represent the speed, volume flow and volume efficiency of the variable frequency compressor respectively, f re , s and p n Represent the frequency, slip rate and pole pair number of the variable frequency compressor respectively, W fre Indicates the power of the inverter compressor.

[0040] Specifically, the reverse osmosis equipment is a one-stage three-stage reverse osmosis equipment, which includes a membrane element and a pressure vessel, wherein the membrane element includes a first-stage membrane element, a second-stage membrane element, and a third-stage membrane element. The reverse osmosis mechanism model is expressed by the following calculation formula:

[0041] Q p1 =Q f -Q r1

[0042] Q f C f =Q p1 C p1 +Q r1 C r1

[0043]

[0044] J v1(z) =A v (ΔP b1(z) -Δπ 1(z) )

[0045] J s1(z) =B s (C m1(z) -Cp1(z) )

[0046] ΔP b1(z) =P b1(z) -P p1(z)

[0047] Δπ 1(z) =RT(C m1(z) -C p1(z) )

[0048]

[0049] J v1(z) =A w ((ΔP b1(z) -P p1(z) )-RT(C m1(z) -C p1(z) ))

[0050]

[0051] J s1(z) =J v1(z) C p1(z)

[0052] Q b1(0) =Q b1(z) +Q p1(z)

[0053] Q b1(0) C b1(0) =Q b1(z) C b1(z) +Q p1(z) C p1(z)

[0054]

[0055]

[0056] λ=6.23K λ Re -0.3

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] M=1.0069-2.757X10 -4 ·T

[0065] Among them, Q f and C f Represent the flow rate and concentration of feed water, Q p1 and C p1 They represent the flow rate and concentration of the water production side of the first membrane element, Q r1 and C r1 Respectively represent the flow rate and concentration of the brine of the first membrane element; n l , w, L and W represent the number of membrane elements, width, effective length and total width of the membrane assembly respectively. w and B s They represent the transport parameters of reverse osmosis membrane for solvent and solute, P b1(z) and P p1(z) Respectively represent the brine pressure and produced water pressure in the first membrane element, R and T represent the gas constant and solution temperature, respectively. m1(z) and C p1(z) They represent the brine concentration on the membrane surface of the first membrane element and the produced water concentration on the produced water side, respectively. 1(z) Indicates the concentration polarization coefficient in the first membrane element, C b1(z) Indicates the brine concentration in the first membrane element, k c1(z) Indicates the mass transfer coefficient in the first membrane element, Q b1(0) , Q b1(z) and Q p1(z) They represent the flow rate of feed water in the first section, the flow rate of brine in the membrane element and the flow rate of produced water side, respectively. b1(0) 、C b1(z) and C p1(z) They represent the concentration of feed water in the first stage, the concentration of brine in the membrane element and the concentration of produced water, respectively. d1(z) Represents the pressure drop loss in the first membrane element, ρ 1(z) Indicates the density of the solution in the first membrane element, V b1(z) Indicates the solution flow rate in the first membrane element, d e represents the hydraulic diameter of the feed membrane gasket, kλ is an empirical value, R e is the Reynolds number, V b1(0) Indicates the flow rate of the first section feed water, ε sp represents the membrane porosity, H represents the height of the feed channel, and D AB represents the diffusion coefficient, S c represents the Schmidt number, ρ (z) Indicates the density of brine in the membrane element, μ (z)Indicates the dynamic viscosity in the membrane element.

[0066] Specifically, the brine outlet of the reverse osmosis equipment is connected to the heat exchanger through a pipeline, and the joint mechanism model is expressed by the following calculation formula:

[0067] M f1 =Q rn ×NP n ×1000

[0068] T cw1 =T fn

[0069] X f1 =C rn ×N n ÷10

[0070] Among them, NP n Indicates the number of pressure vessels of the reverse osmosis equipment, M f1 represents the feed flow rate of the mechanical vapor compression device, Q rn represents the brine flow rate at the nth section outlet of the reverse osmosis device, T cw1 represents the feed temperature of the mechanical vapor compression device, T fn represents the brine temperature at the nth section outlet of the reverse osmosis device, X f1 represents the feed concentration of the mechanical vapor compression device, C rn represents the brine concentration at the outlet of the nth section of the reverse osmosis equipment, n∈(1, 2, 3).

[0071] Specifically, the combined treatment equipment cost calculation model includes a mechanical steam compression equipment cost calculation model and a reverse osmosis equipment cost calculation model. The mechanical steam compression equipment cost calculation model is expressed by the following calculation formula:

[0072] OC com =(H s -H v )×Pric×24×ρ×0.0002778×ε / β com

[0073] OC cir =M f ×24×Pric×ρ×β bemp

[0074] Among them, ε represents the compression ratio, β com Indicates the efficiency of the variable frequency compressor, β bemp Indicates the efficiency of the circulation pump, OC com Indicates the operating cost of the variable frequency compressor, OC cirrepresents the operating cost of the circulation pump, Pric represents the electricity price, and ρ represents the density of the solution.

[0075] Specifically, the reverse osmosis equipment cost calculation model is expressed by the following calculation formula:

[0076] OC CH =0.135Q f

[0077]

[0078]

[0079] OC ME =Pri ME ·NM·ζ re / 360

[0080] OC MN =OC MNCON =0.03OC RO

[0081] OC LB =Pri LB ·N LB

[0082] N LB =Q p NP / 100

[0083] OC=OC IP +OC EN +OC MER +OC MN +OC CH +OC LB

[0084] =OC IP +OC EN +OC MER +OC MNCON +OC CH +OC LB

[0085] =OC IP +OC EN +OC MER +0.03OC RO +OC CH +OC LB

[0086] =(OC IP +OC EN +OC MER +OC CH +OC LB ) / 0.97

[0087] Among them, Q f Indicates the flow rate of feed water of reverse osmosis equipment; P0 indicates the outlet pressure of water pump, Q f Indicates the flow rate of feed water of reverse osmosis equipment, PLF indicates load factor, P elc represents the electricity price, η IP Indicates the efficiency of the seawater intake pump, P f Indicates the feed water pressure of the reverse osmosis equipment, Q f2 and Q p They represent the feed water flow rate of the second membrane element and the produced water flow rate of the reverse osmosis equipment, Pri ME Indicates the unit price of membrane elements, NM indicates the total number of membrane elements in reverse osmosis equipment, ζ re Indicates the replacement rate of membrane components, Ncl indicates the number of times the membrane components are cleaned within the membrane replacement cycle, Xmr indicates the membrane replacement cycle, N LB Represents the number of laborers, P boost Indicates the pressure of the boost pump.

[0088] Specifically, the constraints of the combined treatment equipment include equipment constraints, concentration polarization parameter constraints, and solution flow rate constraints of the reverse osmosis equipment.

[0089] In another aspect, an embodiment of the present invention provides a coal-fired power plant wastewater treatment device, comprising:

[0090] A first model building unit is used to build a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device;

[0091] A second model building unit is used to build a reverse osmosis mechanism model according to the reverse osmosis equipment, wherein the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment;

[0092] a third model building unit, configured to build a joint mechanism model according to a connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize an operating principle of the joint treatment device;

[0093] a fourth model building unit, configured to build a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model;

[0094] The target operation unit is used to calculate and obtain a target operation plan based on the cost calculation model of the joint processing equipment and the constraints of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time.

[0095] In another aspect, an embodiment of the present invention provides an electronic device, comprising:

[0096] at least one processor;

[0097] a memory connected to the at least one processor;

[0098] The memory stores instructions that can be executed by the at least one processor, and the at least one processor implements the aforementioned method by executing the instructions stored in the memory.

[0099] On the other hand, an embodiment of the present invention provides a computer-readable storage medium storing computer instructions. When the computer instructions are executed on a computer, the computer executes the aforementioned method.

[0100] The present invention constructs a combined treatment device based on the principles of high-pressure spiral reverse osmosis and mechanical vapor recompression evaporation for coal-fired power plant wastewater. By using the high-concentration and high-temperature concentrated brine produced by high-pressure spiral reverse osmosis as the feed water for mechanical vapor compression evaporation, the operating cost of the entire combined treatment device is reduced, thereby obtaining the lowest-cost coal-fired power plant wastewater treatment solution.

[0101] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0103] Figure 1 A schematic flow chart of a method for treating coal-fired power plant wastewater according to an embodiment of the present application;

[0104] Figure 2 This is a schematic structural diagram of a combined processing device according to an embodiment of the present application;

[0105] Figure 3 A schematic structural diagram of a coal-fired power plant wastewater treatment device provided by an embodiment of the present invention;

[0106] Figure 4 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0107] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0108] The terms "first", "second", "third", etc. in this application are used to distinguish different objects rather than to describe a specific order. At the same time, the term "include" and any form of its variation are intended to cover non-exclusive inclusions.

[0109] Embodiments of the present application provide a method, device, electronic device, and computer-readable storage medium for treating coal-fired power plant wastewater.

[0110] The device can be integrated into a computer device, which can be a terminal, a server, or other device. The terminal can be a mobile phone, a tablet computer, a smart Bluetooth device, a laptop computer, or a personal computer (PC); the server can be a single server or a server cluster consisting of multiple servers.

[0111] In some embodiments, the device may also be integrated into multiple electronic devices. For example, the device may be integrated into multiple servers, and the method of the present application may be implemented by multiple servers.

[0112] In some embodiments, the server may also be implemented in the form of a terminal.

[0113] It should be noted that the serial numbers of the following embodiments are not intended to limit the preferred order of the embodiments.

[0114] Example 1

[0115] An embodiment of the present invention provides a method for treating coal-fired power plant wastewater, which is applied to a combined treatment device, wherein the combined treatment device includes a reverse osmosis device and a mechanical steam compression device. The reverse osmosis device is used to treat the coal-fired power plant wastewater and obtain concentrated brine, and the mechanical steam compression device is used to treat the concentrated brine obtained by the reverse osmosis device and obtain a crystallizable saturated salt solution and fresh water.

[0116] like Figure 1 The specific process of the method includes steps 110 to 150:

[0117] 110. Establish a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device.

[0118] A mechanistic model, also known as a white-box model, is a precise mathematical model based on the internal mechanisms of an object, a production process, or the transfer mechanism of material flow. It is a mathematical model of an object or process derived from mass balance equations, energy balance equations, momentum balance equations, phase balance equations, certain physical property equations, chemical reaction laws, and basic circuit laws. The advantage of a mechanistic model is that its parameters have very clear physical meanings.

[0119] In some embodiments of the present application, the mechanical vapor compression device includes a heat exchanger, an evaporator, a demister, a variable frequency compressor, and a circulating pump. The mechanical vapor variable frequency compression mechanism model is expressed by the following calculation formula:

[0120] M f =M b +M d

[0121] M f X f =M b X b +M d X d

[0122] Q HX_en =M f ·C pf ·(T f -T cw )

[0123] Q HX_ex =M b ·C pb (T b -T0)+M d ·C pd (T d -T0)

[0124] Q HX_en =Q HX_ex

[0125] Q e_in =M d λ d +M d ·C pv (T s -T d )

[0126] Q e_out =M d λ vp +M f ·C pf (T b -T f )

[0127] Qe_in =Q e_out

[0128] T vp =T b -BPE

[0129] BPE=f·Δ0′

[0130]

[0131] Δ0′=69.8×C b 3 -8.15×C b 2 +5.19×C b

[0132] T vp =T v

[0133] ΔT=T d -T b

[0134] Q e =U e ·A e ·LTMD

[0135] U e =1.9695+1.2057×10 -2 ×T b -8.5989×10 -5 ×T b 2 +2.565×10 -7 ×T b 3

[0136]

[0137] H s =2499.15+1.955×T s -1.927×10 -3 ×T s 2

[0138] W fre =(H s -H v )·0.000277·ε / η com

[0139] η v_fre / η v，ref =d1+d2(N / N ref )+d3(N / N ref) 3

[0140]

[0141]

[0142] d1+d2+d3=1

[0143] e1+e2+e3=1

[0144] N=60f re (1-ss) / p n

[0145] Among them, M d represents the mass flow rate of condensing steam, M b Represents the mass flow rate of concentrated brine, M f represents the feed mass flow rate, X d Indicates the mass percentage concentration of condensed steam, X b Indicates the mass percentage concentration of concentrated brine, X f Indicates the mass percentage concentration of feed water, T f Indicates the temperature after passing through the heat exchanger, T cw Indicates the temperature of feed water, T b Indicates the brine temperature at the evaporator outlet, T d Indicates the temperature of the condensed steam at the evaporator outlet, T b0 Indicates the temperature of the water produced after passing through the heat exchanger, Cp d 、Cp f 、Cp b 、Cp v They represent the specific heat capacity of condensed water, feed water, brine and steam above the demister, Q HX_en , Q HX_ex Respectively represent the heat absorbed and released by the heat exchanger, H s is the enthalpy of the superheated steam after the compressor outlet, H v is the enthalpy of the steam before entering the compressor, d1, d2, d3, e1, e2 and e3 are respectively the conventional coefficients in the mechanical steam variable frequency compression mechanism model, λ vp ,λ d They represent the latent heat below the demister and the latent heat of the steam inside the gate, T s Indicates the temperature of superheated steam, Q e_in , Q e_out Respectively represent the heat generated inside the evaporator tube and outside the switch, T vp Indicates the temperature below the demister, T b represents the boiling point temperature of feed water, BPE represents boiling point elevation, f represents correction factor, T vIndicates the temperature above the demister, Q e represents the heat transfer of the evaporator, U e represents the total heat transfer coefficient, ε represents the compression ratio, η com Indicates the efficiency of the variable frequency compressor, N ref 、V suc,ref and η v,ref Represent the speed, volume flow and volume efficiency of the variable frequency compressor respectively, f re , s and p n Represent the frequency, slip rate and pole pair number of the variable frequency compressor respectively, W fre Indicates the power of the inverter compressor.

[0146] 120. Establish a reverse osmosis mechanism model based on the reverse osmosis equipment, where the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment.

[0147] In some embodiments of the present application, the reverse osmosis device is a one-stage three-stage reverse osmosis device, the one-stage three-stage reverse osmosis device includes a membrane element and a pressure vessel, the membrane element includes a first-stage membrane element, a second-stage membrane element and a third-stage membrane element, and the reverse osmosis mechanism model is expressed by the following calculation formula:

[0148] Q p1 =Q f -Q r1

[0149] Q f C f =Q p1 C p1 +Q r1 C r1

[0150]

[0151] J v1(z) =A w (ΔP b1(z) -Δπ 1(z) )

[0152] J s1(z) =B s (C m1(z) -C p1(z) )

[0153] ΔP b1(z) =P b1(z) -P p1(z)

[0154] Δπ 1(z) =RT(C m1(z) -C p1(z) )

[0155]

[0156] J v1(z) =A w ((ΔP b1(z) -P p1(z) )-RT(C m1(z) -C p1(z) ))

[0157]

[0158] J s1(z) =J v1(z) C p1(z)

[0159] Q b1(0) =Q b1(z) +Q p1(z)

[0160] Q b1(0) C b1(0) =Q b1(z) C b1(z) +Q p1(z) C p1(z)

[0161]

[0162]

[0163] λ=6.23K λ Re -0.3

[0164]

[0165]

[0166]

[0167]

[0168]

[0169]

[0170]

[0171] M=1.0069-2.757×10 -4 ·T

[0172] Among them, Q f and C f Represent the flow rate and concentration of feed water, Q p1 and C p1They represent the flow rate and concentration of the water production side of the first membrane element, Q r1 and C r1 Respectively represent the flow rate and concentration of the brine of the first membrane element; n l , w, L and W represent the number of membrane elements, width, effective length and total width of the membrane assembly respectively. w and B s They represent the transport parameters of reverse osmosis membrane for solvent and solute, P b1(z) and P p1(z) Respectively represent the brine pressure and produced water pressure in the first membrane element, R and T represent the gas constant and solution temperature, respectively. m1(z) and C p1(z) They represent the brine concentration on the membrane surface of the first membrane element and the produced water concentration on the produced water side, respectively. 1(z) Indicates the concentration polarization coefficient in the first membrane element, C b1(z) Indicates the brine concentration in the first membrane element, k c1(z) Indicates the mass transfer coefficient in the first membrane element, Q b1(0) , Q b1(z) and Q p1(z) They represent the flow rate of feed water in the first section, the flow rate of brine in the membrane element and the flow rate of produced water side, respectively. b1(0) 、C b1(z) and C p1(z) They represent the concentration of feed water in the first stage, the concentration of brine in the membrane element and the concentration of produced water, respectively. d1(z) Represents the pressure drop loss in the first membrane element, ρ 1(z) Indicates the density of the solution in the first membrane element, V b1(z) Indicates the solution flow rate in the first membrane element, d e represents the hydraulic diameter of the feed membrane gasket, kλ is an empirical value, R e is the Reynolds number, V b1(0) Indicates the flow rate of the first section feed water, ε sp represents the membrane porosity, H represents the height of the feed channel, and D AB represents the diffusion coefficient, S c represents the Schmidt number, ρ (z) Indicates the density of brine in the membrane element, μ (z) Indicates the dynamic viscosity in the membrane element.

[0173] At the same time, it should be pointed out that for other one-stage multi-stage reverse osmosis equipment, the internal connection element mode can be expressed by the following expression:

[0174]

[0175] C fn =C r(n-1)

[0176] P fn =P r(n-1) +P_boost

[0177] Among them, Q fn , C fn and P fn They represent the feed flow rate, feed concentration and feed pressure of the nth section respectively, Q r(n-1) 、C r(n-1) and P r(n-1) Indicates the brine flow rate, concentration and pressure to the n-1th section, NP (n-1) and NP n Respectively represent the number of pressure vessels in the n-1th and nth sections, P_ boost Indicates the pressure of the boost pump.

[0178] 130. Establish a joint mechanism model based on the connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize the operating principle of the joint processing device.

[0179] In some embodiments of the present application, the brine outlet of the reverse osmosis device is connected to the heat exchanger through a pipeline, and the joint mechanism model is expressed by the following calculation formula:

[0180] M f1 =Q rn ×NP n ×1000

[0181] T cw1 =T fn

[0182] X f1 =C rn ×N n ÷10

[0183] Among them, NP n Indicates the number of pressure vessels of the reverse osmosis equipment, M f1 represents the feed flow rate of the mechanical vapor compression device, Q rn represents the brine flow rate at the nth section outlet of the reverse osmosis device, T cw1 represents the feed temperature of the mechanical vapor compression device, T fn represents the brine temperature at the nth section outlet of the reverse osmosis device, X f1 represents the feed concentration of the mechanical vapor compression device, C rn represents the brine concentration at the outlet of the nth section of the reverse osmosis equipment, n∈(1, 2, 3).

[0184] 140. Establish a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model.

[0185] In some embodiments of the present application, the combined treatment equipment cost calculation model includes a mechanical steam compression equipment cost calculation model and a reverse osmosis equipment cost calculation model. The mechanical steam compression equipment cost calculation model is represented by the following calculation formula:

[0186] OC com =(H s -H v )×Pric×24×ρ×0.0002778×ε / β com

[0187] OC cir =M f ×24×Pric×ρ×β bemp

[0188] Among them, ε represents the compression ratio, β com Indicates the efficiency of the variable frequency compressor, β bemp Indicates the efficiency of the circulation pump, OC com Indicates the operating cost of the variable frequency compressor, OC cir represents the operating cost of the circulation pump, Pric represents the electricity price, and ρ represents the density of the solution.

[0189] Continuing with the above embodiment, the reverse osmosis equipment cost calculation model is expressed by the following calculation formula:

[0190] OC CH =0.135Q f

[0191]

[0192]

[0193] OC ME =Pri ME ·NM·ζ re / 360

[0194] OC MN =OC MNCON =0.03OC RO

[0195] OC LB =Pri LB ·N LB

[0196] N LB =Q pNP / 100

[0197] OC=OC IP +OC EN +OC MER +OC MN +OC CH +OC LB

[0198] =OC IP +OC EN +OC MER +OC MNCON +OC CH +OC LB

[0199] =OC IP +OC EN +OC MER +0.03OC RO +OC CH +OC LB

[0200] =(OC IP +OC EN +OC MER +OC CH +OC LB ) / 0.97

[0201] Among them, Q f Indicates the flow rate of feed water to the reverse osmosis equipment. P0 indicates the outlet pressure of the water pump, Q f Indicates the flow rate of feed water of reverse osmosis equipment, PLF indicates load factor, P elc represents the electricity price, η IP Indicates the efficiency of the seawater intake pump, P f Indicates the feed water pressure of the reverse osmosis equipment, Q f2 and Q p They represent the feed water flow rate of the second membrane element and the produced water flow rate of the reverse osmosis equipment, Pri ME Indicates the unit price of membrane elements, NM indicates the total number of membrane elements in reverse osmosis equipment, ζ re Indicates the replacement rate of membrane components, Ncl indicates the number of times the membrane components are cleaned within the membrane replacement cycle, Xmr indicates the membrane replacement cycle, N LB Expressed as the number of laborers, P_ boost Indicates the pressure of the boost pump.

[0202] 150. Calculate and obtain a target operation plan based on the cost calculation model of the joint processing equipment and the constraints of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time.

[0203] In some embodiments of the present application, in order to minimize the average daily cost of the combined processing equipment, the feed conditions are adjusted in units of 24 hours, taking into account the constraints. The feed conditions are feed flow rate Q f , feed concentration C f , Booster pump pressure P_ boost , the feed flow rate M of the evaporator f and the frequency f of the variable frequency compressor re Therefore, the minimum operating cost corresponding to the target operation scheme can be expressed as:

[0204]

[0205] Specifically, the constraints of the combined treatment equipment include equipment constraints, concentration polarization parameter constraints, and solution flow rate constraints of the reverse osmosis equipment. The equipment constraints can be expressed by the following expression:

[0206]

[0207]

[0208] P_boost L ≤P_boost≤P_boost U

[0209]

[0210] The concentration polarization parameter constraint can be expressed by the following expression:

[0211] φ≤φ U

[0212] The solution flow rate constraint of the reverse osmosis equipment can be expressed by the following expression:

[0213]

[0214] The superscripts L and U refer to the upper and lower limits of the parameters, respectively.

[0215] In some embodiments of the present application, the aforementioned calculation formulas and expressions include both nonlinear algebraic equations and differential equations. To facilitate solution, the differential equations in the aforementioned model can be discretized to form a nonlinear optimization problem. The nonlinear solver of the GAMS platform is then used to optimize and solve the problem, obtaining the target operating solution that minimizes the operating cost of the combined processing equipment.

[0216] Specifically, step 150 includes steps 151 to 152 as shown in the following specific process:

[0217] Step 151: Discretize the aforementioned calculation formula and expression.

[0218] Step 152: Establish an optimization proposition and solve the optimization proposition. The optimization proposition is expressed by the following expression:

[0219]

[0220] c(x)=0

[0221] x L ≤x≤x U

[0222] Wherein, F(x) represents the objective function, i.e., the operating cost corresponding to the joint processing equipment, c(x)=0 represents the equality constraint, and x L ≤x≤x U represents the inequality constraint, and the final solution obtained is the aforementioned feeding condition, that is, the target operation plan.

[0223] The embodiment of the present application constructs a combined treatment device based on the principles of high-pressure spiral reverse osmosis and mechanical vapor recompression evaporation of coal-fired power plant wastewater. By using the high-concentration and high-temperature concentrated brine produced by high-pressure spiral reverse osmosis as the feed water for mechanical vapor compression evaporation, the operating cost of the entire combined treatment device is reduced, thereby obtaining the lowest-cost coal-fired power plant wastewater treatment solution.

[0224] In order to better understand the present invention, the following examples are given. Figure 2 , the present invention is further elaborated.

[0225] Example 2

[0226] The embodiment of the present invention and embodiment 1 belong to the same inventive concept. Figure 2 As shown, an embodiment of the present invention provides a combined treatment device comprising a one-stage three-stage reverse osmosis device and a mechanical steam compression device.

[0227] Specifically, the specific operation process of the combined processing equipment includes:

[0228] Coal-fired power plant wastewater passes through a high-pressure pump and reaches the first stage of a three-stage reverse osmosis device. The first stage produces fresh water and concentrated brine. The concentrated brine passes through a booster pump and reaches the second stage for further treatment. Fresh water and concentrated brine are also produced at the same time. The concentrated brine produced serves as the feed water for the third stage, which produces fresh water and concentrated brine. The fresh water produced by the three-stage membrane element is the produced water of the three-stage reverse osmosis device, and the concentrated brine produced by the third-stage membrane element is the concentrated brine of the three-stage reverse osmosis device. The concentrated brine of the three-stage reverse osmosis device serves as the feed water of the mechanical vapor compression device. The feed water of the mechanical vapor compression device first passes through a heat exchanger for sufficient heat exchange, which increases the temperature of the feed water, improves energy utilization, and achieves energy saving. The feed water is then transported to the evaporation chamber by a circulating pump for spraying and evaporation for secondary evaporation. It is compressed by a variable frequency compressor to produce high-temperature and high-pressure steam, which is then transported to the heating chamber of the evaporator for use as heating steam, thus achieving a cycle.

[0229] The embodiment of the present application constructs a combined treatment device based on the principles of high-pressure spiral reverse osmosis and mechanical vapor recompression evaporation of coal-fired power plant wastewater. By using the high-concentration and high-temperature brine produced by high-pressure spiral reverse osmosis as the feed water for mechanical vapor compression evaporation, the operating cost of the entire combined treatment device is reduced, providing a complete hardware facility foundation for the aforementioned method.

[0230] Example 3

[0231] The embodiment of the present invention and embodiment 1 and 2 all belong to the same inventive concept. The embodiment of the present invention provides a device for estimating the service life of an old well to be re-injected, such as Figure 3 As shown, the device includes:

[0232] A first model building unit 301 is configured to build a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is configured to characterize the operating principle of the mechanical steam compression device;

[0233] A second model building unit 302 is configured to build a reverse osmosis mechanism model based on the reverse osmosis device, wherein the reverse osmosis mechanism model is configured to characterize the operating principle of the reverse osmosis device;

[0234] A third model building unit 303 is configured to build a joint mechanism model according to the connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize the operating principle of the joint treatment device;

[0235] A fourth model building unit 304 is configured to build a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model;

[0236] The target operation unit 305 is configured to calculate a target operation plan based on the cost calculation model of the joint processing equipment and the constraints of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time.

[0237] In specific implementation, the above units can be implemented as independent entities, or can be arbitrarily combined to be implemented as the same or several entities. The specific implementation of the above units can be found in the previous method embodiments and will not be repeated here.

[0238] Example 4

[0239] The embodiment of the present invention and embodiments 1, 2, and 3 all belong to the same inventive concept. The embodiment of the present invention provides an electronic device, the electronic device

[0240] It can be a terminal, server, etc. Among them, the terminal can be a mobile phone, tablet computer, smart Bluetooth device, laptop computer, personal computer, etc. The server can be a single server or a server cluster composed of multiple servers, etc.

[0241] In some embodiments, the apparatus may also be integrated into multiple devices. For example, the apparatus may be integrated into multiple servers, and the method of the present application may be implemented by multiple servers.

[0242] For example, Figure 4 , which shows a schematic diagram of the structure of the device involved in the embodiment of the present application, specifically:

[0243] The device may include one or more processing core processors 401, one or more storage media memories 402, a power supply 403, an input module 404, and a communication module 405. Those skilled in the art will appreciate that Figure 4 The device structure shown in the figure does not constitute a limitation of the device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0244] Processor 401 is the control center of the device, connecting all components of the device using various interfaces and circuits. It executes software programs and / or modules stored in memory 402 and accesses data stored in memory 402 to perform various device functions and process data. In some embodiments, processor 401 may include one or more processing cores. In some embodiments, processor 401 may integrate an application processor and a modem processor. The application processor primarily handles the operating system, user interface, and application programs, while the modem processor primarily handles wireless communications. It is understood that the modem processor may not be integrated into processor 401.

[0245] The memory 402 can be used to store software programs and modules. The processor 401 executes various functional applications and data processing by running the software programs and modules stored in the memory 402. The memory 402 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the device, etc. In addition, the memory 402 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage device. Accordingly, the memory 402 may also include a memory controller to provide the processor 401 with access to the memory 402.

[0246] The device also includes a power supply 403 for supplying power to various components. In some embodiments, the power supply 403 can be logically connected to the processor 401 via a power management system, thereby enabling the power management system to manage charging, discharging, and power consumption. The power supply 403 can also include one or more DC or AC power supplies, a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator, and other arbitrary components.

[0247] The device may further include an input module 404, which may be configured to receive input digital or character information and generate keyboard, mouse, joystick, optical or trackball signal input related to user settings and function control.

[0248] The device may also include a communication module 405. In some embodiments, the communication module 405 may include a wireless module. The device may perform short-range wireless transmission via the wireless module of the communication module 405, thereby providing the user with wireless broadband Internet access. For example, the communication module 405 may be used to help the user send and receive emails, browse web pages, and access streaming media.

[0249] Although not shown, the device may further include a display unit, etc., which will not be described in detail here. Specifically, in this embodiment, the processor 401 in the device will load the executable files corresponding to one or more application processes into the memory 402 according to the following instructions, and the processor 401 will run the application stored in the memory 402 to implement various functions as follows:

[0250] Establishing a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device;

[0251] Establishing a reverse osmosis mechanism model based on the reverse osmosis equipment, wherein the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment;

[0252] Establishing a joint mechanism model based on the connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize the operating principle of the joint treatment device;

[0253] Establishing a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model;

[0254] A target operation plan is obtained by calculation based on the cost calculation model of the joint processing equipment and the constraint conditions of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time.

[0255] The specific implementation of the above operations can be found in the previous embodiments and will not be repeated here.

[0256] Those skilled in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be accomplished through instructions, or through instruction-controlled related hardware. The instructions may be stored in a storage medium and loaded and executed by a processor.

[0257] To this end, an embodiment of the present application provides a computer-readable storage medium storing a plurality of instructions that can be loaded by a processor to execute the steps of any of the methods provided in the embodiments of the present application. For example, the instructions can execute the following steps:

[0258] Establishing a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device;

[0259] Establishing a reverse osmosis mechanism model based on the reverse osmosis equipment, wherein the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment;

[0260] Establishing a joint mechanism model based on the connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize the operating principle of the joint treatment device;

[0261] Establishing a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model;

[0262] A target operation plan is obtained by calculation based on the cost calculation model of the joint processing equipment and the constraint conditions of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time.

[0263] The specific implementation of the above operations can be found in the previous embodiments and will not be repeated here.

[0264] The storage medium may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0265] Since the instructions stored in the storage medium can execute the steps in any one of the methods provided in the embodiments of the present application, the beneficial effects that can be achieved by any one of the methods provided in the embodiments of the present application can be achieved. Please refer to the previous embodiments for details and will not be repeated here.

[0266] The above describes in detail some optional implementation methods of some embodiments of the present invention in conjunction with the accompanying drawings. However, the embodiments are not limited to the specific details of the above implementation methods. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the scope of protection of the embodiments of the present invention.

[0267] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0268] In addition, various implementations of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A method for treating coal-fired power plant wastewater, characterized in that: The method is applied to a combined treatment device, the combined treatment device including a reverse osmosis device and a mechanical vapor compression device, the reverse osmosis device is used to treat coal-fired power plant wastewater and obtain concentrated brine, and the mechanical vapor compression device is used to treat the concentrated brine obtained by the reverse osmosis device and obtain a crystallizable saturated salt solution and fresh water. The method comprises: Establishing a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device; Establishing a reverse osmosis mechanism model based on the reverse osmosis equipment, wherein the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment; Establishing a joint mechanism model based on the connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize the operating principle of the joint treatment device; Establishing a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model; Calculating and obtaining a target operation plan based on the cost calculation model of the combined processing equipment and the constraints of the combined processing equipment so as to minimize the operation cost of the combined processing equipment within a specific time; The mechanical steam compression equipment includes a heat exchanger, an evaporator, a demister, a variable frequency compressor, and a circulation pump. The mechanical steam variable frequency compression mechanism model is expressed by the following calculation formula: M f =M b +M d M f X f =M b X b +M d X d Q HX_en =M f ·C pf ·(T f -T cw ) Q HX_ex =M b ·C pb (T b -T0)+M d ·C pd (T d -T0) Q HX_en =Q HX_ex Q e_in =M d λ d +M d ·C pv (T s -T d ) Q e_out =M d λ vp +M f ·C pf (T b -T f ) Q e_in =Q e_out T vp =T b -BPE BPE=f·Δ0′ Δ0′=69.8×C b 3 -8.15×C b 2 +5.19×C b T vp =T v ΔT=T d -T b Q e =U e ·YOUR e ·LTMD W fre =(H s -H v )·0.000277·e / d com η v_fre / η v，ref =d1+d2(N / N ref )+d3(N / N ref ) 3 d1+d2+d3=1 e1+e2+e3=1 N=60f re (1-ss) / p n Among them, M d represents the mass flow rate of condensing steam, M b Represents the mass flow rate of concentrated brine, M f represents the feed mass flow rate, X d Indicates the mass percentage concentration of condensed steam, X b Indicates the mass percentage concentration of concentrated brine, X f Indicates the mass percentage concentration of feed water, T f Indicates the temperature of the concentrated brine after passing through the heat exchanger, T cw Indicates the temperature of feed water, T b Indicates the brine temperature at the evaporator outlet, T d Indicates the temperature of the condensed steam at the evaporator outlet, T0 indicates the temperature of the condensed water after passing through the heat exchanger, C pd 、C pf 、C pb 、C pv They represent the specific heat capacity of condensed water, feed water, brine and steam above the demister, Q HX_en , Q HX_ex Respectively represent the heat absorbed and released by the heat exchanger, H s is the enthalpy of the superheated steam after the compressor outlet, H v is the enthalpy of the steam before entering the compressor, d1, d2, d3, e1, e2 and e3 are respectively the conventional coefficients in the mechanical steam variable frequency compression mechanism model, λ vp ,λ d They represent the latent heat below the demister and the latent heat of the steam in the tube, T s Indicates the temperature of superheated steam, Q e_in , Q e_out Respectively represent the heat generated inside and outside the tube in the evaporator, T vp represents the temperature below the demister, BPE represents the boiling point elevation, f represents the correction factor, T v Indicates the temperature above the demister, Q e represents the heat transfer of the evaporator, U e represents the total heat transfer coefficient, ε represents the compression ratio, η com Indicates the efficiency of the variable frequency compressor, N ref 、V suc，ref and η v，ref Represent the speed, volume flow and volume efficiency of the variable frequency compressor respectively, f re and p n Represent the frequency and pole pairs of the variable frequency compressor, W fre represents the power of the variable frequency compressor, Δ′0 represents the boiling point rise of the solution under normal pressure, ΔT represents the heat transfer temperature difference of the evaporator, r represents the latent heat of vaporization of water under the current working conditions, C b Indicates the mass fraction of the given discharge brine, A e represents the heat exchange area of ​​the evaporator, LMTD represents the logarithmic mean temperature difference, N represents the speed of the compressor, W represents the standard power consumption of the compressor, ss represents the slip, V suc_fre represents the specific volume of the steam at the compressor inlet, η v_fre Indicates the efficiency of the compressor; The reverse osmosis equipment is a one-stage three-stage reverse osmosis equipment, which includes a membrane element and a pressure vessel. The membrane element includes a first-stage membrane element, a second-stage membrane element, and a third-stage membrane element. The reverse osmosis mechanism model is expressed by the following calculation formula: Q p1 =Q f -Q r1 Q f C f =Q p1 C p1 +Q r1 C r1 J v1(z) =A w (ΔP b1(z) -Dp 1(z) ) J s1(z) =B s (C m1(z) -C p1(z) ) ΔP b1(z) =P b1(z) -P p1(z) Dp 1(z) =RT(C m1(z) -C p1(z) ) J v1(z) =A w ((ΔP b1(z) -P p1(z) )-RT(C m1(z) -C p1(z) )) I s1(z) =J v1(z) C p1(z) Q b1(0) =Q b1(z) +Q p1(z) Q b1(0) C b1(0) =Q b1(z) C b1(z) +Q p1(z) C p1(z) λ=6.23K λ Re -0.3 M=1.0069-2.757×10 -4 ·T Among them, Q f and C f Represent the flow rate and concentration of feed water, Q p1 and C p1 They represent the flow rate and concentration of the water production side of the first membrane element, Q r1 and C r1 Respectively represent the flow rate and concentration of the brine of the first membrane element; n l , w, L and W represent the number of membrane elements, width, effective length and total width of the membrane assembly respectively. w and B s They represent the transport parameters of reverse osmosis membrane for solvent and solute, P b1(z) and P p1(z) Respectively represent the brine pressure and produced water pressure in the first membrane element, R and T represent the gas constant and solution temperature, respectively. m1(z) and C p1(z) They represent the brine concentration on the membrane surface of the first membrane element and the water concentration on the water production side, respectively. 1(z) Indicates the concentration polarization coefficient in the first membrane element, C b1(z) Indicates the brine concentration in the first membrane element, k c1(z) Indicates the mass transfer coefficient in the first membrane element, Q b1(0) , Q b1(z) and Q p1(z) They represent the flow rate of feed water in the first section, the flow rate of brine in the membrane element and the flow rate of produced water side, respectively. b1(0) 、C b1(z) and C p1(z) They represent the concentration of feed water in the first stage, the concentration of brine in the membrane element and the concentration of produced water, respectively. d1(z) Indicates the pressure drop loss in the first membrane element, ρ 1(z) Indicates the density of the solution in the first membrane element, V b1(z) Indicates the solution flow rate in the first membrane element, d e Indicates the hydraulic diameter of the feed membrane gasket, K λ is the experience value, R e is the Reynolds number, V b1(0) Indicates the flow rate of the first section feed water, ε sp represents the membrane porosity, H represents the height of the feed channel, and D AB represents the diffusion coefficient, S c represents the Schmidt number, ρ (z) Indicates the density of brine in the membrane element, μ (z) Indicates the dynamic viscosity in the membrane element, J V represents the solvent flux of the membrane element, J V1(Z) represents the solvent flux at membrane channel z, J S1(Z) represents the solute flux at the membrane channel z, λ represents the friction factor, k c represents the mass transfer coefficient, C b(Z) Indicates the salt concentration of the brine in the membrane element, M process variable, Δπ 1(z) represents the osmotic pressure difference at the z position of the membrane channel, ΔP b1(z) represents the transmembrane pressure difference at the membrane channel position z, V represents the flow rate in the channel, k c(z) represents the mass transfer coefficient at the z position of the membrane channel; The brine outlet of the reverse osmosis device is connected to the heat exchanger through a pipeline, and the joint mechanism model is expressed by the following calculation formula: M f1 =Q r，n ×NP n ×1000 T cw1 =T fn X f1 =C r，n ×N n ÷10 Among them, NP n Indicates the number of pressure vessels of the reverse osmosis equipment, M f1 represents the feed flow rate of the mechanical vapor compression device, Q r，n represents the brine flow rate at the nth section outlet of the reverse osmosis device, T cw1 represents the feed temperature of the mechanical vapor compression device, T fn represents the brine temperature at the nth section outlet of the reverse osmosis device, X f1 represents the feed concentration of the mechanical vapor compression device, C r，n represents the brine concentration at the nth outlet of the reverse osmosis device, n∈(1, 2, 3), N n Indicates the number of pressure vessels in the nth section of the reverse osmosis equipment; The combined treatment equipment cost calculation model includes a mechanical steam compression equipment cost calculation model and a reverse osmosis equipment cost calculation model. The mechanical steam compression equipment cost calculation model is expressed by the following calculation formula: OC com =(H s -H v )×Pric×24×ρ×0.0002778×ε / β com OC cir =M f ×24×Pric×ρ×β bemp Among them, ε represents the compression ratio, β com Indicates the efficiency of the variable frequency compressor, β bemp Indicates the efficiency of the circulation pump, OC com Indicates the operating cost of the variable frequency compressor, OC cir represents the operating cost of the circulation pump, Pric represents the electricity price, and ρ represents the density of the solution; The reverse osmosis equipment cost calculation model is expressed by the following formula: OC CH =0.135Q f Third Party Liability ME =Pri ME ·NM·ζ re / 360 OC MN =OC MNCON =0.03OC RO OC LB =Pri LB ·N LB N LB =Q p ·NP / 100 OC=OC IP +OC EN +OC ME +OC MN +OC CH +OC LB =OC IP +OC EN +OC ME +OC MNCON +OC CH +OC LB =OC IP +OC EN +OC ME +0.03OC RO +OC CH +OC LB Among them, OC CH Indicates the average daily cost of adding chemicals, OC IP represents the average daily water extraction energy cost, OC EN represents the average daily energy consumption cost of reverse osmosis equipment operation, ε p Represents the mechanical efficiency of the high-pressure pump, ε VFD Indicates the mechanical efficiency of the variable frequency drive, ε bp Indicates the mechanical efficiency of the interstage booster pump, OC ME Indicates the average daily membrane element maintenance cost, OC MN and OC MNCON represents the average daily system maintenance cost, OC RO Indicates the average daily cost of system operation, OC LB represents the average daily wage cost, Pri LB represents the average daily wage, NP represents the total number of pressure vessels, OC represents the average daily operating cost, Q f Indicates the flow rate of feed water of reverse osmosis equipment; P0 indicates the outlet pressure of water pump, PLF indicates the load factor, P elc represents the electricity price, η IP Indicates the efficiency of the seawater intake pump, P f Indicates the feed water pressure of the reverse osmosis equipment, Q f2 and Q p They represent the feed water flow rate of the second membrane element and the produced water flow rate of the reverse osmosis equipment, Pri ME Indicates the unit price of membrane elements, NM indicates the total number of membrane elements in reverse osmosis equipment, ζ re Indicates the replacement rate of membrane components, N LB represents the number of laborers, P_boost represents the pressure of the booster pump; The constraints of the combined treatment equipment include equipment constraints, concentration polarization parameter constraints, and solution flow rate constraints of the reverse osmosis equipment.

2. A coal-fired power plant wastewater treatment device, characterized in that: The device comprises: A first model building unit is used to build a mechanical steam variable frequency compression mechanism model based on the mechanical steam compression device, wherein the mechanical steam variable frequency compression mechanism model is used to characterize the operating principle of the mechanical steam compression device; A second model building unit is used to build a reverse osmosis mechanism model according to the reverse osmosis equipment, wherein the reverse osmosis mechanism model is used to characterize the operating principle of the reverse osmosis equipment; a third model building unit, configured to build a joint mechanism model according to a connection mode between the reverse osmosis device and the mechanical vapor compression device, wherein the joint mechanism model is used to characterize an operating principle of the joint treatment device; a fourth model building unit, configured to build a combined treatment equipment cost calculation model based on the mechanical steam variable frequency compression mechanism model, the reverse osmosis mechanism model, and the combined mechanism model; a target operation unit, configured to calculate and obtain a target operation plan based on the cost calculation model of the joint processing equipment and the constraints of the joint processing equipment, so as to minimize the operation cost of the joint processing equipment within a specific time; The mechanical steam compression equipment includes a heat exchanger, an evaporator, a demister, a variable frequency compressor, and a circulation pump. The mechanical steam variable frequency compression mechanism model is expressed by the following calculation formula: M f =M b +M d M f X f =M b X b +M d X d Q HX_en =M f ·C pf ·(T f -T cw ) Q HX_ex =M b ·C pb (T b -T0)+M d ·C pd (T d -T0) Q HX_en =Q HX_ex Q e_in =M d λ d +M d ·C pv (T s -T d ) Q e_out =M d λ vp +M f ·C pf (T b -T f ) Q e_in =Q e_out T vp =T b -BPE BPE=f·Δ0′ Δ0′=69.8×C b 3 -8.15×C b 2 +5.19×C b T vp =T v ΔT=T d -T b Q e =U e ·YOUR e ·LTMD W fre =(H s -H v )·0.000277·e / d com η v_fre / η v，ref =d1+d2(N / N ref )+d3(N / N ref ) 3 d1+d2+d3=1 e1+e2+e3=1 N=60f re (1-ss) / p n Among them, M d represents the mass flow rate of condensing steam, M b Represents the mass flow rate of concentrated brine, M f represents the feed mass flow rate, X d Indicates the mass percentage concentration of condensed steam, X b Indicates the mass percentage concentration of concentrated brine, X f Indicates the mass percentage concentration of feed water, T f Indicates the temperature of the concentrated brine after passing through the heat exchanger, T cw Indicates the temperature of feed water, T b Indicates the brine temperature at the evaporator outlet, T d Indicates the temperature of the condensed steam at the evaporator outlet, T0 indicates the temperature of the condensed water after passing through the heat exchanger, C pd 、C pf 、C pb 、C pv They represent the specific heat capacity of condensed water, feed water, brine and steam above the demister, Q HX_en , Q HX_ex Respectively represent the heat absorbed and released by the heat exchanger, H s is the enthalpy of the superheated steam after the compressor outlet, H v is the enthalpy of the steam before entering the compressor, d1, d2, d3, e1, e2 and e3 are respectively the conventional coefficients in the mechanical steam variable frequency compression mechanism model, λ vp ,λ d They represent the latent heat below the demister and the latent heat of the steam in the tube, T s Indicates the temperature of superheated steam, Q e_in , Q e_out Respectively represent the heat generated inside and outside the tube in the evaporator, T vp represents the temperature below the demister, BPE represents the boiling point elevation, f represents the correction factor, T v Indicates the temperature above the demister, Q e represents the heat transfer of the evaporator, U e represents the total heat transfer coefficient, ε represents the compression ratio, η com Indicates the efficiency of the variable frequency compressor, N ref 、V suc，ref and η v，ref Represent the speed, volume flow and volume efficiency of the variable frequency compressor respectively, f re and p n Represent the frequency and pole pairs of the variable frequency compressor, W fre represents the power of the variable frequency compressor, Δ′0 represents the boiling point rise of the solution under normal pressure, ΔT represents the heat transfer temperature difference of the evaporator, r represents the latent heat of vaporization of water under the current working conditions, C b Indicates the mass fraction of the given discharge brine, A e represents the heat exchange area of ​​the evaporator, LMTD represents the logarithmic mean temperature difference, N represents the speed of the compressor, W represents the standard power consumption of the compressor, ss represents the slip, V suc_fre represents the specific volume of the steam at the compressor inlet, η v_fre Indicates the efficiency of the compressor; The reverse osmosis equipment is a one-stage three-stage reverse osmosis equipment, which includes a membrane element and a pressure vessel. The membrane element includes a first-stage membrane element, a second-stage membrane element, and a third-stage membrane element. The reverse osmosis mechanism model is expressed by the following calculation formula: Q p1 =Q f -Q r1 Q f C f =Q p1 C p1 +Q r1 C r1 J v1(z) =A w (ΔP b1(z) -Dp 1(z) ) J s1(z) =B s (C m1(z) -C p1(z) ) ΔP b1(z) =P b1(z) -P p1(z) Dp 1(z) =RT(C m1(z) -C p1(z) ) J v1(z) =A w ((ΔP b1(z) -P p1(z) )-RT(C m1(z) -C p1(z) )) I s1(z) =J v1(z) C p1(z) Q b1(0) =Q b1(z) +Q p1(z) Q b1(0) C b1(0) =Q b1(z) C b1(z) +Q p1(z) C p1(z) λ=6.23K λ Re -0.3 M=1.0069-2.757×10 -4 ·T Among them, Q f and C f Represent the flow rate and concentration of feed water, Q p1 and C p1 They represent the flow rate and concentration of the water production side of the first membrane element, Q r1 and C r1 Respectively represent the flow rate and concentration of the brine of the first membrane element; n l , w, L and W represent the number of membrane elements, width, effective length and total width of the membrane assembly respectively. w and B s They represent the transport parameters of reverse osmosis membrane for solvent and solute, P b1(z) and P p1(z) Respectively represent the brine pressure and produced water pressure in the first membrane element, R and T represent the gas constant and solution temperature, respectively. m1(z) and C p1(z) They represent the brine concentration on the membrane surface of the first membrane element and the water concentration on the water production side, respectively. 1(z) Indicates the concentration polarization coefficient in the first membrane element, C b1(z) Indicates the brine concentration in the first membrane element, k c1(z) Indicates the mass transfer coefficient in the first membrane element, Q b1(0) , Q b1(z) and Q p1(z) They represent the flow rate of feed water in the first section, the flow rate of brine in the membrane element and the flow rate of produced water side, respectively. b1(0) 、C b1(z) and C p1(z) They represent the concentration of feed water in the first stage, the concentration of brine in the membrane element and the concentration of produced water, respectively. d1(z) Indicates the pressure drop loss in the first membrane element, ρ 1(z) Indicates the density of the solution in the first membrane element, V b1(z) Indicates the solution flow rate in the first membrane element, d e Indicates the hydraulic diameter of the feed membrane gasket, K λ is the experience value, R e is the Reynolds number, V b1(0) Indicates the flow rate of the first section feed water, ε sp represents the membrane porosity, H represents the height of the feed channel, and D AB represents the diffusion coefficient, S c represents the Schmidt number, ρ (z) Indicates the density of brine in the membrane element, μ (z) Indicates the dynamic viscosity in the membrane element, J V represents the solvent flux of the membrane element, J V1(Z) represents the solvent flux at membrane channel z, J S1(Z) represents the solute flux at the membrane channel z, λ represents the friction factor, k c represents the mass transfer coefficient, C b(Z) Indicates the salt concentration of the brine in the membrane element, M process variable, Δπ 1(z) represents the osmotic pressure difference at the z position of the membrane channel, ΔP b1(z) represents the transmembrane pressure difference at the membrane channel position z, V represents the flow rate in the channel, k c(z) represents the mass transfer coefficient at the z position of the membrane channel; The brine outlet of the reverse osmosis device is connected to the heat exchanger through a pipeline, and the joint mechanism model is expressed by the following calculation formula: M f1 =Q r，n ×NP n ×1000 T cw1 =T fn X f1 =C r，n ×N n ÷10 Among them, NP n Indicates the number of pressure vessels of the reverse osmosis equipment, M f1 represents the feed flow rate of the mechanical vapor compression device, Q r，n represents the brine flow rate at the nth section outlet of the reverse osmosis device, T cw1 represents the feed temperature of the mechanical vapor compression device, T fn represents the brine temperature at the nth section outlet of the reverse osmosis device, X f1 represents the feed concentration of the mechanical vapor compression device, C r，n represents the brine concentration at the nth outlet of the reverse osmosis device, n∈(1, 2, 3), N n Indicates the number of pressure vessels in the nth section of the reverse osmosis equipment; The combined treatment equipment cost calculation model includes a mechanical steam compression equipment cost calculation model and a reverse osmosis equipment cost calculation model. The mechanical steam compression equipment cost calculation model is expressed by the following calculation formula: OC com =(H s -H v )×Pric×24×ρ×0.0002778×ε / β com OC cir =M f ×24×Pric×ρ×β bemp Among them, ε represents the compression ratio, β com Indicates the efficiency of the variable frequency compressor, β bemp Indicates the efficiency of the circulation pump, OC com Indicates the operating cost of the variable frequency compressor, OC cir represents the operating cost of the circulation pump, Pric represents the electricity price, and ρ represents the density of the solution; The reverse osmosis equipment cost calculation model is expressed by the following formula: OC CH =0.135Q f Third Party Liability ME =Pri ME ·NM·ζ re / 360 OC MN =OC MNCON =0.03OC RO OC LB =Pri LB ·N LB N LB =Q p ·NP / 100 OC=OC IP +OC EN +OC ME +OC MN +OC CH +OC LB =OC IP +OC EN +OC ME +OC MNCON +OC CH +OC LB =OC IP +OC EN +OC ME +0.03OC RO +OC CH +OC LB Among them, OC CH Indicates the average daily cost of adding chemicals, OC IP represents the average daily water extraction energy cost, OC EN represents the average daily energy consumption cost of reverse osmosis equipment operation, ε p Represents the mechanical efficiency of the high-pressure pump, ε VFD Indicates the mechanical efficiency of the variable frequency drive, ε bp Indicates the mechanical efficiency of the interstage booster pump, OC ME Indicates the average daily membrane element maintenance cost, OC MN and OC MNCON represents the average daily system maintenance cost, OC RO Indicates the average daily cost of system operation, OC LB represents the average daily wage cost, Pri LB represents the average daily wage, NP represents the total number of pressure vessels, OC represents the average daily operating cost, Q f Indicates the flow rate of feed water of reverse osmosis equipment; P0 indicates the outlet pressure of water pump, PLF indicates the load factor, P elc represents the electricity price, η IP Indicates the efficiency of the seawater intake pump, P f Indicates the feed water pressure of the reverse osmosis equipment, Q f2 and Q p They represent the feed water flow rate of the second membrane element and the produced water flow rate of the reverse osmosis equipment, Pri ME Indicates the unit price of membrane elements, NM indicates the total number of membrane elements in reverse osmosis equipment, ζ re Indicates the replacement rate of membrane components, N LB represents the number of laborers, P_boost represents the pressure of the booster pump; The constraints of the combined treatment equipment include equipment constraints, concentration polarization parameter constraints, and solution flow rate constraints of the reverse osmosis equipment.

3. An electronic device, characterized in that: The electronic device includes: at least one processor; a memory connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the at least one processor implements the method of claim 1 by executing the instructions stored in the memory. 4 . A computer-readable storage medium storing computer instructions, which, when executed on a computer, cause the computer to execute the method according to claim 1 .

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