Energy optimization control method and system in cement production process

Abstract

The invention discloses an energy optimization control method and system in a cement production process. The method comprises the following steps: establishing a load characteristic model of each device in the cement production process; based on the established load characteristic model, constructing a cement production process energy optimization control model considering load interruptability; photovoltaic output and load power in the cement production process are obtained, and an uncertainty set is constructed based on the obtained data; and based on the established energy optimization control model and the obtained photovoltaic output and load power, constructing a two-stage robust optimization model, and obtaining the optimization interruption cost and the work time of the interruptible equipment of the cement plant. The production cost can be remarkably reduced, the energy utilization efficiency can be improved, and the market competitiveness and sustainable development capability of a cement plant can be enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of energy optimization control in cement production process, and in particular relates to an energy optimization control method and system for cement production process. Background Art

[0002] In recent years, demand response has been increasingly valued as a key measure to improve energy efficiency and ensure the balance of supply and demand in the power system. In view of the complex industrial environment, strict requirements are placed on the reliability and accuracy of demand response, especially in the cement manufacturing industry. The complex dynamic characteristics of cement production process are high, and it is difficult to balance the complexity of cement industry production energy demand and the randomness of real-time dynamic electricity prices. It is also difficult to overcome the complex dynamic characteristics of cement industry processes, which easily leads to the difficulty of accurate energy optimization control when the load scheduling of cement industry users is difficult, and the overall industrial production energy cost is high. There are significant limitations in dealing with complex cement industry load demand response problems.

[0003] Load interruptibility refers to the fact that during cement production, some equipment or process links can suspend or reduce load operation for a certain period of time without affecting the overall production process. This feature provides a new idea for energy optimization control. By reasonably scheduling and arranging equipment or process links with load interruptibility, flexible scheduling and optimal utilization of energy can be achieved while ensuring production continuity and stability. However, there is currently no mature energy optimization control method and device for cement production process that takes load interruptibility into consideration.

[0004] CN202210260483.3A discloses a method for responding to electricity demand based on the discontinuous production process and storage capacity of cement enterprises. This method aims at the discontinuous production process in the cement industry, adds a material storage link, and coordinates the production process of the cement enterprise cluster with the renewable energy power abandonment curve of the renewable energy power generator or the excess power generation curve of the power grid, so that the cement enterprise cluster can absorb more energy when the renewable energy power abandonment is serious or the power grid generates excess power. The invention focuses on a single optimization goal of electricity demand response and storage scheduling, such as minimizing operating costs. However, in actual applications, comprehensive consideration is needed. The integration and coordination between the various systems within the cement enterprise have not yet been fully realized, resulting in information islands and inefficiency.

[0005] Therefore, there is an urgent need for an energy optimization control method for the cement production process, which takes into account the fact that the production process of cement enterprises involves multiple links and multiple goals such as energy consumption, emissions, and production efficiency, to improve energy utilization efficiency. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides an energy optimization control method for a cement production process, selects interruptible loads with a larger proportion in the adjustable loads of a cement plant for demand response, and refines the cost calculation model of the interruptible loads of a cement plant.

[0007] The present invention adopts the following technical solution.

[0008] A method for optimizing energy control in a cement production process, characterized in that the method comprises:

[0009] Step 1: Establish the load characteristic model of each equipment in the cement production process;

[0010] Step 2: Based on the load characteristic model established in step 1, an energy optimization control model for the cement production process considering load interruptibility is constructed;

[0011] Step 3: Obtain the photovoltaic output and load power during the cement production process, and construct an uncertainty set based on the acquired data;

[0012] Step 4: Based on the energy optimization control model established in step 2 and the photovoltaic output and load power obtained in step 3, a two-stage robust optimization model is constructed to obtain the optimized interruption cost and rush time of the interruptible equipment in the cement plant.

[0013] The present invention further includes the following preferred embodiments.

[0014] In step 1, establishing the load characteristic model of each device in the cement production process includes: establishing a calculation formula for the power of the rotary kiln motor; establishing a calculation formula for the power of the belt conveyor motor; and establishing a power calculation formula for the grinding mill.

[0015] The formula for calculating the power of the rotary kiln motor is as follows:

[0016]

[0017] Among them, N M is the power required by the rotary kiln motor, N1 is the effective power, N2 is the friction power, η is the mechanical efficiency, when the closed reducer is driven, η=0.90, n is the rotation speed of the kiln, L is the length of the kiln barrel; R is the effective inner radius of the kiln, α is half of the central angle subtended by the chord of the arch area of ​​the material accumulation in the kiln, f is the friction coefficient, γ is the radius of the supporting roller journal, G is the sum of the mass of the rotating part of the kiln body plus the mass of all the supporting rollers and shafts, D is the outer diameter of the wheel band, d is the diameter of the tugboat, and K is the reserve coefficient.

[0018] The calculation formula of belt conveyor motor power is as follows:

[0019]

[0020] Among them, N 电 is the belt conveyor motor power, K1LV represents the no-load running power of the conveyor; K2QL represents the power for horizontal material conveying; QH represents the power for vertical material lifting; K a is the power safety factor and full-load start-up factor, K3 is the factor related to the horizontal projection length of the conveyor, and K4 is the factor related to the layout of the conveyor; η P represents the total transmission efficiency of the belt conveyor motor; ξ is the material conveying coefficient; N sa Indicates the total operating power of the belt conveyor motor.

[0021] The power calculation formula of the mill is as follows:

[0022]

[0023] Where, N0 is the power of the mill; V is the effective volume of the mill; D0 is the effective inner diameter of the mill; n g G is the working speed of the mill; Y is the grinding body loading.

[0024] In step 2, the construction formula of the energy optimization control model of the cement production process considering the interruptibility of load is as follows:

[0025]

[0026] Among them, C L Indicates rush work cost; minC L Indicates the minimum value of rush work cost; x i The flag indicating whether process i is interrupted or not, x i When it is 0, it means that process i is not interrupted, x i When it is 1, it means that process i is interrupted; T mi represents the minimum advance notice time, T represents the actual advance notice time, Δt mi represents the maximum interruption time of process i, Δt represents the actual interruption time, S l Indicates the actual load interruption capacity, L m represents the minimum load interruption capacity, t p0i Indicates the start time of rush work for process i, T fi It represents the transferable time interval of process i.

[0027] Cost of rush work C L The calculation formula is as follows:

[0028] C L =C gd +C gud ;

[0029] Among them, Cgd represents the direct cost of rush work, C gud Represents the indirect cost of rush work.

[0030] Direct cost of rush work C gd The calculation formula is as follows:

[0031]

[0032] Among them, T pe Indicates rush time, t po Indicates the start time of rush work; t lo represents the interruption start time, Δt represents the interruption duration, C L (t) represents the total cost of interruptible load, C E (t) represents the unit electricity cost, C M represents the material cost of rush work, W represents the manufacturing cost allocated per unit time, and P l Indicates the interrupted load power, n pe Indicates the number of workers required for the rush process.

[0033] Indirect cost of rush work C gud The calculation formula is as follows:

[0034] C gud =C B +C O +C C +Q4+Q5;

[0035] Among them, C B represents the waste loss, C O represents the start-stop cost, C C represents the carbon emission cost in the cement production process, Q4 represents the profit lost due to reduced production, and Q5 represents the profit loss due to increased defective products.

[0036] In step 3, the formula for constructing the uncertainty set is as follows:

[0037]

[0038] In the formula, U represents the box type uncertainty set, N T represents the scheduling period, represents the predicted value of photovoltaic output during period t, represents the predicted value of load power in period t, u PV (t) and u L (t) is the uncertain variable of photovoltaic output and load power; and is the maximum fluctuation deviation allowed for the two.

[0039] In step 4, the construction formula of the two-stage robust optimization model is as follows:

[0040]

[0041] Where c is the coefficient column vector; D, K, F, G and I u is the coefficient matrix; d and h are constant column vectors, and x, u and y are all optimization variables; is the predicted value of the uncertain variable; the outer minimization is the first-stage problem, which means minimizing the interruptible cost; the inner maximization is the second-stage problem, and Ω(x,u) is the feasible domain of the variable y.

[0042] At the same time, the present invention also provides an energy optimization control system for a cement production process, comprising a load characteristic model building module, an energy optimization control model building module, a parameter acquisition module and a robust optimization model building module;

[0043] Load characteristic model building module, used to build load characteristic models of various equipment in cement production process;

[0044] Energy optimization control model building module, based on the established load characteristic model, builds an energy optimization control model for the cement production process that takes load interruptibility into account;

[0045] The parameter acquisition module is used to obtain the photovoltaic output and load power in the cement production process and build an uncertainty set based on the acquired data;

[0046] The robust optimization model building module constructs a two-stage robust optimization model based on the established energy optimization control model and the obtained photovoltaic output and load power to obtain the optimized interruption cost and rush time of the cement plant's interruptible equipment.

[0047] A terminal comprises a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of any one of the methods.

[0048] A computer-readable storage medium stores a computer program, which implements the steps of any one of the methods when executed by a processor.

[0049] The beneficial effect of the present invention lies in that, compared with the prior art, the present invention selects interruptible loads with a larger proportion in the adjustable loads of cement plants for demand response, and performs refined modeling of the cost calculation model of interruptible loads of cement plants. According to the interruptible capacity of interruptible equipment for cement production, operating parameter constraints are set, such as minimum advance notice time constraints, maximum interruption time constraints, minimum interruption load constraints, etc., an uncertainty set is constructed for photovoltaic output and load uncertain variables, and a two-stage robust optimization model is constructed with the minimum cost of interruptible loads as the goal, so as to obtain the optimized interruption cost and rush time of interruptible equipment in cement plants, which can not only significantly reduce production costs and improve energy utilization efficiency, but also enhance the market competitiveness and sustainable development capabilities of cement plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a diagram of the energy system architecture of a cement plant in an embodiment of the present invention;

[0051] Figure 2 It is a schematic diagram of the electricity costs of different processes in the direct cost of interruption;

[0052] Figure 3 It is a schematic diagram of the labor costs of different processes in the direct cost of interruption. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0054] A cement plant energy system architecture, such as Figure 1 As shown in the figure, the system covers the entire process of cement production: starting from the crushing of raw materials, through fine raw material grinding, entering the key clinker burning stage, the raw materials are converted into clinker; then, the clinker is further ground into cement powder through the clinker grinding process; finally, it goes through the cement packaging process and then shipped out of the factory. During this process, the system is connected to the power grid to ensure a stable supply of electricity for production. At the same time, in order to improve energy efficiency and reduce the impact on the environment, the system is also equipped with a photovoltaic energy storage device, which uses solar energy to generate electricity and store excess electricity, providing strong support for the green transformation of cement production.

[0055] The present invention provides a method for optimizing energy control in a cement production process, comprising:

[0056] Step 1: Establish the load characteristic model of each equipment in the cement production process;

[0057] The load characteristic model of each equipment in the cement production process includes:

[0058] Establish a formula for calculating the power of the rotary kiln motor; establish a formula for calculating the power of the belt conveyor motor; and establish a formula for calculating the power of the grinding mill.

[0059] The rotary kiln motor power calculation formula is as follows:

[0060]

[0061] Among them, N M is the power required by the rotary kiln motor, N1 is the effective power, N2 is the friction power, η is the mechanical efficiency, when the closed reducer is driven, η=0.90, n is the rotation speed of the kiln, L is the length of the kiln barrel; R is the effective inner radius of the kiln, α is half of the central angle subtended by the chord of the arch area of ​​the material accumulation in the kiln, f is the friction coefficient, γ is the radius of the supporting roller journal, G is the sum of the mass of the rotating part of the kiln body plus the mass of all the supporting rollers and shafts, D is the outer diameter of the wheel band, d is the diameter of the tugboat, and K is the reserve coefficient.

[0062] The calculation formula of the belt conveyor motor power is as follows:

[0063]

[0064] Among them, N 电 is the belt conveyor motor power, K1LV represents the no-load running power of the conveyor; K2QL represents the power for horizontal material conveying; QH represents the power for vertical material lifting; K is the power safety factor and full-load starting factor, K a is the power safety factor and full-load start-up factor, K3 is the factor related to the horizontal projection length of the conveyor, and K4 is the factor related to the layout of the conveyor; η P It represents the total transmission efficiency of the belt conveyor motor; N is the motor power of the mill; N sa It indicates the total operating power of the belt conveyor motor; ξ is the material conveying coefficient. When the material is conveyed upward, ξ=1, and when the material is conveyed downward, ξ=-1. Among them, upward and downward only indicate the direction and have nothing to do with the sequence of the process. When the horizontal projection length of the conveyor is long, such as greater than 100m, k3 is preferably between 1.15-1.2; if the horizontal projection length is moderate, such as between 30-60m, k3 is preferably between 1.25-1.4. k4 is preferably between 1 and 1.16.

[0065] Where N sa As shown below:

[0066]

[0067] in, To indicate the power of the unloading device; Indicates the power of the sweeper; Indicates the friction power of the guide chute baffle plate; Indicates the material acceleration power; Indicates the total power of other additional devices.

[0068] The power calculation formula of the mill is as follows:

[0069]

[0070] Where, N0 is the power of the mill; V is the effective volume of the mill; D0 is the effective inner diameter of the mill; n g G is the working speed of the mill; Y is the grinding body loading.

[0071] Step 2: Based on the load characteristic model established in step 1, an energy optimization control model for the cement production process considering load interruptibility is constructed;

[0072] The construction formula of the energy optimization control model of cement production process considering load interruptibility is as follows:

[0073]

[0074] Among them, C L Indicates rush work cost; minC L Indicates the minimum value of rush work cost; x i The flag indicating whether process i is interrupted or not, x i When it is 0, it means that process i is not interrupted, x i When it is 1, it means that process i is interrupted; T mi represents the minimum advance notice time, T represents the actual advance notice time, Δt mi represents the maximum interruption time of process i, Δt represents the actual interruption time, S l Indicates the actual load interruption capacity, L m represents the minimum load interruption capacity, t p0i Indicates the start time of rush work for process i, T fi It represents the transferable time interval of process i.

[0075] Cost of rush work C L The calculation formula is as follows:

[0076] C L =C gd +C gud ;

[0077] Among them, C gd represents the direct cost of rush work, C gudRepresents the indirect cost of rush work.

[0078] Direct cost of rush work C gd The calculation formula is as follows:

[0079]

[0080] Among them, T pe Indicates rush time, t po Indicates the start time of rush work; t lo represents the interruption start time, Δt represents the interruption duration, C L (t) represents the total cost of interruptible load, C E (t) represents the unit electricity cost, W represents the manufacturing cost allocated per unit time, P l Indicates the interrupted load power, n pe Indicates the number of workers required for the rush process.

[0081] Indirect cost of rush work C gud The calculation formula is as follows:

[0082] C gud =C B +C O +C C +Q4+Q5;

[0083] Among them, C B represents the waste loss, C O represents the start-stop cost, C C represents the carbon emission cost in the cement production process, Q4 represents the profit lost due to reduced production, and Q5 represents the profit loss due to increased defective products.

[0084] Step 3: Obtain the photovoltaic output and load power during the cement production process, and construct an uncertainty set based on the acquired data;

[0085] The formula for constructing the uncertainty set is as follows:

[0086]

[0087] In the formula, U represents the box type uncertainty set, N T represents the scheduling period, represents the predicted value of photovoltaic output during period t, represents the predicted value of load power in period t, u PV (t) and u L (t) is the uncertain variable of photovoltaic output and load power; and is the maximum fluctuation deviation allowed for the two.

[0088] The construction formula of the two-stage robust optimization model is as follows:

[0089]

[0090] Where c is the coefficient column vector corresponding to the objective function; D, K, F, G and I u The coefficient matrix corresponding to the variables in the constraints of the energy optimization control model of cement production process considering load interruptibility; d and h are constant column vectors. The outer minimization is the first-stage problem, and the optimization variable is x, which represents the minimization of interruptibility cost; the inner maximum minimization is the second-stage problem, corresponding to the optimization variables u and y; is the predicted value of the uncertain variable; the outer minimization is the first-stage problem, which means minimizing the interruptible cost; the inner maximization is the second-stage problem, and Ω(x,u) is the feasible domain of the variable y.

[0091] Step 4: Based on the energy optimization control model established in step 2 and the photovoltaic output and load power obtained in step 3, a two-stage robust optimization model is constructed to obtain the optimized interruption cost and rush time of the interruptible equipment in the cement plant.

[0092] Example

[0093] A cement production process energy optimization control method, comprising:

[0094] Step 1: Establish the load characteristic model of each equipment in the cement production process.

[0095] In one embodiment of the present invention, in step 1, establishing the load characteristic model of each device in the cement production process includes: establishing a rotary kiln motor power calculation formula; establishing a belt conveyor motor power calculation formula; and establishing a mill power calculation formula.

[0096] like Figure 1 The figure shows the energy system architecture of a cement plant in an embodiment of the present invention. The load characteristic model of each device in the cement production process includes: continuous operation load, interruptible load and curtailable load.

[0097] Furthermore, the continuous operation load refers to the load borne by the equipment that needs to run continuously to maintain the production process during the cement production process. Such equipment is usually the key equipment in the production process, and its suspension will directly affect the continuity and stability of the entire production line.

[0098] In one embodiment of the present invention, taking a rotary kiln as an example, a common power calculation formula for a rotary kiln is:

[0099]

[0100] Among them, NM is the power required by the rotary kiln motor, N1 is the effective power, N2 is the friction power, η is the mechanical efficiency, when the closed reducer is driven, η=0.90, n is the kiln speed, its unit is r / min, L is the length of the kiln barrel, its unit is m; R is the effective inner radius of the kiln, its unit is m, α is half of the central angle subtended by the chord of the arch area of ​​the material accumulation in the kiln / degree, f is the friction coefficient, γ is the radius of the supporting roller journal, its unit is m, G is the sum of the mass of the rotating part of the kiln body plus the mass of all the supporting rollers and shafts, its unit is t, D is the outer diameter of the wheel band, and d is the diameter of the tug.

[0101] The calculation formula of rotary kiln motor power is as follows:

[0102] N M =KN (2)

[0103] Among them, N M is the motor power, its unit is kW, K is the reserve factor, generally 1.15-1.35.

[0104] The interruptible load refers to the load borne by the equipment that can be safely interrupted under specific circumstances without affecting the overall production process or causing significant losses. This type of load is usually agreed with the power grid or production management department through an economic contract or agreement to ensure that it can be flexibly adjusted when needed; specific circumstances include power grid peak hours, equipment failures, production adjustments, etc.

[0105] In one embodiment of the present invention, taking the interruptible load equipment belt conveyor as an example, the belt conveyor driving roller shaft power, the unit is kW, is calculated as follows:

[0106] N 轴 =[K1LV+K2QL+ξ*(3.1-0.00273QH)]K3K4+N sa (3)

[0107] Among them, K1LV-no-load running power of conveyor, its unit is kW; K2QL-horizontal material conveying power, its unit is kW; QH-vertical material lifting power, its unit is kW, ξ is material conveying coefficient; upward conveying takes "+" sign, downward conveying takes "-" sign; N sa Indicates the total operating power of the belt conveyor motor.

[0108] Calculation of belt conveyor motor power in kW:

[0109]

[0110] Where N 轴-Drive roller shaft power, in kW; K-power safety factor and full-load starting factor, K=1.2~1.4; η P -Total transmission efficiency is usually 0.8~0.9. When using a reduction gearbox for transmission, η=0.88 is used for the smooth roller and η=0.9 is used for the rubber roller.

[0111] In one embodiment of the present invention, the reducible load refers to the load borne by the equipment that can be adjusted and reduced within a certain range according to production requirements or energy saving and consumption reduction goals during the cement production process. Such loads usually include some auxiliary equipment or non-critical equipment in the production process, and their operating loads can be adjusted according to actual conditions.

[0112] Taking the mill as an example, the mill production capacity is determined as follows:

[0113]

[0114] Among them, Q is the mill production capacity, its unit is t / h; N0 is the power required by the mill, its unit is kW; q is the unit power output, its unit is t / (kW·h); η is the process coefficient.

[0115] Mill power:

[0116]

[0117] Among them, N0 is the power required by the mill, its unit is kW; V is the effective volume of the mill, its unit is m 3 ; D0 is the effective inner diameter of the mill, its unit is m; n g is the working speed of the mill, its unit is r / min; G Y is the grinding body loading, and its unit is t.

[0118] Power of motor for grinding mill:

[0119] N=K1K2N0 (7)

[0120] Among them, K1 is a coefficient related to the mill structure and transmission efficiency. The center drive and edge drive dry grinding are 1.25 and 1.3 respectively; the center drive and edge drive unloading grinding are 1.35 and 1.4 respectively; K2 is the motor reserve coefficient, which is between 1.0-1.1.

[0121] Mill ventilation calculation:

[0122]

[0123] Where Q is the ventilation volume required by the mill, and its unit is m 3 / h; D iis the effective diameter of the mill, in m; is the mill grinding body filling rate, expressed as a decimal; W is the mill wind speed, its unit is m / s.

[0124] Furthermore, the interruptible load cost composition includes determining waste loss, production cost, start-up and shutdown cost, saving cost and carbon emission cost.

[0125] Determining scrap loss includes:

[0126] Scrap can be divided into two types: repairable and non-repairable. Repairable scrap refers to the scrap that can be restored to its use value after repair and is economically viable. These products may be found to be defective or damaged during the production process or storage, but they may be restored to their original performance or value through repair. On the contrary, scrap that cannot be repaired to restore its use value is called non-repairable scrap.

[0127] Define the repairable cost Q1:

[0128]

[0129] Among them, T re The time for repairing scrap; t r0 C is the starting time of waste repair; L (t) is the unit labor cost; n re The number of workers required to repair the scrap; C E (t) is the unit electricity cost; P re is the power of scrap repair equipment; W is the manufacturing cost allocated per unit time.

[0130] Define the irreparable cost Q2:

[0131]

[0132] Among them, C M is the material cost; C R is the residual value of the waste, T ce The time used for waste production; t c0 The starting time of waste production; n ce The number of workers required to produce the waste; P ce The power of the equipment used to produce the waste.

[0133] The scrap loss is:

[0134] C B =Q1+Q2 (11)

[0135] Determining the production cost includes:

[0136] Due to load interruption, the output of cement plants will decrease during the planned production cycle, which will in turn affect the benefits of cement plants. In order to reduce the negative impact, enterprises can compensate for it by rushing work. Therefore, production loss involves multiple cost factors, including labor costs and operating costs during rushing work, loss of revenue due to reduced output, and reduced revenue due to increased defective rate.

[0137] Define the direct cost of rush work Q3:

[0138]

[0139] Among them, T pe To rush the work time; p0 To rush the work start time; n pe The number of workers required for the rush process; P pe is the load power of the rush equipment; W is the manufacturing cost allocated per unit time; C M The cost of materials for rush work.

[0140] Profits lost due to reduced production Q4:

[0141] Q4=(p pr -p a +p g )·μ (13)

[0142] Among them, p pr is the planned output, p a is the actual output after the load interruption, p g To speed up production, μ is the profit margin of genuine products.

[0143] Define the profit loss due to increased defective products Q5:

[0144] Q5=p B ·(μ-μ') (14)

[0145] Among them, p B is the quantity of scrap and μ' is the profit rate of defective products.

[0146] The production cost is:

[0147] C P =Q3+Q4+Q5 (15)

[0148] Determining the start-stop cost includes:

[0149] The start-up and shutdown costs of cement plant equipment mainly involve various expenses incurred during the start-up and shutdown process of the equipment, including equipment preheating, precooling, initial energy consumption, manual operation costs, and possible equipment losses.

[0150] Define the start-stop assist cost Q6:

[0151]

[0152] Among them, C Mo is the auxiliary material cost, T o To rush the work time; o0 To rush the work start time; n o P is the number of manpower required for start and stop; o is the start-stop power of the auxiliary equipment; W is the manufacturing cost allocated per unit time;

[0153] Define the cost of self-generated power generation Q7:

[0154] Q7=C me ·T me +T o ·W (17)

[0155] Among them, C me is the labor cost and energy cost per unit time, T me is the power generation time; W is the manufacturing cost allocated per unit time.

[0156] The start-stop cost is:

[0157] C O =Q6+Q7 (18)

[0158] The cost savings determined include:

[0159] The cost savings of interruptible loads mainly include the reduced energy consumption costs due to the implementation of load interruption, namely electricity costs, material costs and contract / temporary wages.

[0160] Defining cost savings S :

[0161]

[0162] Among them, C Ms is the cost of unused materials; C W for unpaid wages; l0 is the interruption start time; P l is the interrupted load power; W is the manufacturing cost allocated per unit time.

[0163] Determining the carbon emission cost includes:

[0164] The cement industry is one of the world's major sources of carbon dioxide emissions, and its carbon emissions mainly come from fuel combustion and carbonate decomposition during the production process. In the cement production process, the calculation formula for the carbon emission cost of cement production is:

[0165]

[0166] Where α1 is the artificial carbon emission factor; n C is the carbon emission per unit power; α2 is the carbon emission factor of manufacturing cost per unit time; α3 is the carbon emission factor of materials.

[0167] Define the total interruptible load cost C of the cement plant L for:

[0168] C L =C B +C P +C O +C C -C S (twenty one)

[0169] Step 2: Based on the load characteristic model established in step 1, an energy optimization control model for the cement production process is constructed taking into account the interruptibility of the load.

[0170] In one embodiment of the present invention, further, the energy optimization control model of the cement production process considering the interruptibility of load is:

[0171] In the actual production process, the waste loss C generated by the load interruption in the cement plant B and the start-stop cost C O than the production cost C P The cost of production is much smaller and is not directly affected by the rush plan. Among the production costs, the loss Q4 caused by reduced production and the loss Q5 due to defective products can also be considered to be unrelated to the rush plan; assuming that the rush equipment power P pe With interrupt device power P l equal to ensure that the output remains unchanged. Assume that the material cost and the saving cost C in the direct cost of rush work Q3 M Unused material cost C Ms In order to maximize the benefits of the cement plant, it is necessary to minimize the interruption cost by optimizing the rush time and the selection of interrupted processes.

[0172] P pe =P l

[0173] C M =C Ms

[0174] Define the direct cost of rush work C gd :

[0175]

[0176] Then the indirect cost of rush work is C gud :

[0177] C gud =C L -C gd =C B +C O +C C +Q4+Q5 (23)

[0178] Total cost C L That is:

[0179] C L =C gd +C gud (twenty four)

[0180] By optimizing the rush time and the selection of interrupted processes, the benefits of the cement plant can be maximized. For a production line with n processes, define the flag x that indicates whether process i is interrupted or not i for:

[0181]

[0182] Where i=1,2,...,n.

[0183] The model is established as follows:

[0184] min C L (25)

[0185] st

[0186] x i ·T mi ≤T (26)

[0187] x i ·Δt mi ≥Δt (27)

[0188] S l ≥L m (28)

[0189] t p0i ∈T fi (29)

[0190] Among them, C L represents the rush work cost; x i The flag indicating whether process i is interrupted or not, x i When it is 0, it means that process i is not interrupted, x i When it is 1, it means that process i is interrupted; T mi represents the minimum advance notice time, T represents the actual advance notice time, Δt mi represents the maximum interruption duration, Δt represents the actual interruption duration, S l Indicates the actual load interruption capacity, Lm represents the minimum load interruption capacity, t p0i Indicates the start time of rush work, T fi It represents the transferable time interval of process i.

[0191] The constraint conditions (26), (27) and (28) are the minimum advance notice time constraint, the maximum interruption time constraint and the minimum load interruption capacity constraint respectively.

[0192] This optimization problem is NP-hard. If there are many steps in the production process, the solution will become extremely complicated. However, if only one step is considered and it is assumed to be interrupted, the problem can be transformed into a single-objective linear programming problem, which is easier to solve.

[0193] Now we only consider one process i in the cement production process, assuming that it is interrupted, that is, x i =1, the interruption duration is Δt hours.

[0194] In order to improve factory management efficiency, the rush work plan should be set in a continuous time period as much as possible. The working period after load transfer can be determined as follows:

[0195] T si =[t si |t si ∈(t p0i ,t p0i +T pei )] (30)

[0196] When the advance notice time T is less than 24, the time interval for process i to be transferred is:

[0197] T fi =[t fi |t fi ∈(t ei ,t si +24-Δt)] (31)

[0198] When the advance notice time T≥24, the time interval for process i to be transferred is:

[0199] T fi =[t fi |t fi ∈(t ei -24,t si -Δt)∪(t ei ,t si +24-Δt)] (32)

[0200] Among them, t ei ,t si are the end and start times of process i when it runs normally.

[0201] From the above analysis, we can see that only the direct cost of rush work C gd It will have a direct impact on the rush work time. For the convenience of calculation, the indirect cost C of rush work can be ignored for the time being. gud Therefore, we only need to find the minimum direct cost of rushing work for process i and then add it up. So the optimization problem can be simplified to the following model:

[0202] The objective function is:

[0203]

[0204] The constraints are:

[0205] t p0i ∈T fi

[0206] Where i = 1, 2, ..., n; P li =P pei ; T pei =Δt.

[0207] Now the original NP-hard problem is transformed into a linear optimization problem, which is easier to solve. p0i Substituting into formula (5.1-1), the obtained T si This is the optimal rush work plan for process i. gdi is the minimum direct rush cost of process i, plus the indirect rush cost C gud This is the minimum cost of load interruption for process i, namely:

[0208] C Lmi =C gdmi +C gud (34)

[0209] After obtaining the minimum interruption cost of each process, the total cost of load interruption in the cement plant can be obtained by adding them up.

[0210]

[0211] Step 3: Obtain the PV output and load power during cement production, and construct an uncertainty set based on the acquired data.

[0212] The uncertainty set constructed by the uncertain variables includes: the fluctuation of photovoltaic power generation and the variation range of load power are limited to the box-type uncertainty set. The photovoltaic output and load power uncertain variables u introduced after considering the uncertainty PV (t) and u L (t). Using the maximum fluctuation deviation allowed by photovoltaic output and load power and Combined with the uncertain variables, a box-shaped uncertainty set U is constructed. The relationship between the box-shaped uncertainty set U and the model is mainly reflected in the uncertainty of the model input.

[0213] In one embodiment of the present invention, the randomness of photovoltaic output and load fluctuation is considered, and a box-type uncertainty set is constructed:

[0214]

[0215] In the formula, u PV (t) and u L (t) is the uncertain variable of photovoltaic output and load power; and It is the maximum fluctuation deviation allowed for the two, and the value is positive.

[0216] Step 4: Based on the energy optimization control model established in step 2 and the photovoltaic output and load power obtained in step 3, a two-stage robust optimization model is constructed to obtain the optimized interruption cost and rush time of the interruptible equipment in the cement plant.

[0217] The two-stage robust optimization model is as follows: 0 / 1 variables, continuous variables and uncertain variables are used as first-stage and second-stage optimization variables respectively, the minimization of interruptible load cost is used as the optimization target, and the interruption capacity of each interruptible load is used as the constraint.

[0218] In one embodiment of the present invention, a two-stage robust optimization model is constructed as follows:

[0219]

[0220] Where c is the coefficient column vector; D, K, F, G and I u is the coefficient matrix; d and h are constant column vectors, and x, u and y are optimization variables. is the predicted value of the uncertain variable; the outer minimization is the first-stage problem, which means minimizing the interruptible cost; the inner maximization is the second-stage problem, and Ω(x,u) is the feasible domain of the variable y.

[0221] The predicted value of the uncertain variable is determined by the following formula:

[0222]

[0223] In the formula, and They represent the predicted values ​​of photovoltaic output and load power in period t respectively.

[0224] In the first stage, the goal is to minimize the interruptible costs in the entire dispatch cycle, including waste loss, production loss, start-up and shutdown costs, carbon emission costs, savings costs, etc. In the second stage, considering the uncertainty factors such as renewable energy photovoltaics and load volatility, the goal is to minimize the additional costs caused by interrupted load adjustment under all possible uncertainty scenarios. This is usually achieved by solving a "min-max" problem, that is, minimizing the cost in the worst case.

[0225] Constraints represents the minimum interruption load constraint in the energy optimization control model of cement production process; stDy≥d is an inequality constraint, including the constraints of minimum advance notice time and maximum interruption time; Ky=0, Fx+Gy≥h and It means that in the deterministic optimization model, the values ​​of photovoltaic output and load power are constraints on the corresponding predicted values ​​in each time period.

[0226] The present invention is further described below with reference to specific examples.

[0227] A cement plant has more than 500 electrical equipments and the average daily load is 10600.75kW. According to the method proposed in the previous section, the interruptible cost of the plant is calculated and the interruption power production plan is made.

[0228] Combined with the actual situation of the cement plant, the electricity price function is:

[0229]

[0230] According to the local income situation and the regulations of the cement plant, the labor cost function is:

[0231]

[0232] From the analysis, it can be seen that the main factor affecting the load interruption cost and interruption strategy is the direct cost of rushing in the production cost. In the process of optimization and solution, the minimum direct cost of rushing and the start time of rushing for each process in one day are first required. This can greatly simplify the calculation process, facilitate subsequent solutions, and meet the load interruption management strategy of the cement plant. The optimization results of the direct cost of load interruption rushing and rushing time are shown in Table 1.

[0233]

[0234]

[0235] according to Figure 2 and Figure 3The calculation results show that the electricity and labor costs of processes 17 and 19 are significantly greater than those of other interruptible processes. This is because the power of the main interruptible equipment in these two processes is too large, and the interruption of the load will seriously affect the output of cement products, resulting in high energy consumption costs. At the same time, these two processes are scheduled to rush work from 0:00 to 8:00 at night. At this time, the unit labor cost is at a high level, which is bound to cause a large total labor cost. For these two processes, the cost of electricity accounts for a large proportion of the production cost, and the electricity price at night is at the lowest level, so rushing work at night is arranged to greatly reduce the cost of electricity.

[0236] For other interruptible processes, rush work is arranged during the day from 9:00 to 17:00 because the labor cost required for these processes accounts for a large proportion of the total production cost, which is determined by the number of workers required for the process. From the labor cost function, it can be seen that the labor cost required for rush work during the day is small, so rush work is arranged during the day to minimize the production cost caused by load interruption.

[0237] Precisely because electricity costs and labor costs are time-sensitive and their changes may not be consistent, different processes may have different optimal rush times after being interrupted.

[0238] At the same time, the present invention realizes an energy optimization control system for cement production process taking into account the interruptibility of load, including a load characteristic model construction module, an energy optimization control model construction module, a parameter acquisition module and a robust optimization model construction module;

[0239] Load characteristic model building module, used to build load characteristic models of various equipment in cement production process;

[0240] Energy optimization control model building module, based on the established load characteristic model, builds an energy optimization control model for the cement production process that takes load interruptibility into account;

[0241] The parameter acquisition module is used to obtain the photovoltaic output and load power in the cement production process and build an uncertainty set based on the acquired data;

[0242] The robust optimization model building module constructs a two-stage robust optimization model based on the established energy optimization control model and the obtained photovoltaic output and load power to obtain the optimized interruption cost and rush time of the cement plant's interruptible equipment.

[0243] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0244] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0245] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0246] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0247] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing energy control in cement production process, characterized in that: The method comprises: Step 1: Establish the load characteristic model of each equipment in the cement production process; Step 2: Based on the load characteristic model established in step 1, an energy optimization control model for the cement production process considering load interruptibility is constructed; Step 3: Obtain the photovoltaic output and load power during the cement production process, and construct an uncertainty set based on the acquired data; Step 4: Based on the energy optimization control model established in step 2 and the photovoltaic output and load power obtained in step 3, a two-stage robust optimization model is constructed to obtain the optimized interruption cost and rush time of the interruptible equipment in the cement plant.

2. The energy optimization control method for cement production process according to claim 1, characterized in that: In step 1, the load characteristic model of each equipment in the cement production process is established including: Establish a formula for calculating the power of rotary kiln motor; Establish a calculation formula for belt conveyor motor power; And establish the power calculation formula of the mill.

3. The energy optimization control method for cement production process according to claim 2 is characterized in that: The formula for calculating the power of the rotary kiln motor is as follows: Among them, N M is the power required by the rotary kiln motor, N1 is the effective power, N2 is the friction power, η is the mechanical efficiency, when the closed reducer is driven, η=0.90, n is the rotation speed of the kiln, L is the length of the kiln barrel; R is the effective inner radius of the kiln, α is half of the central angle subtended by the chord of the arch area of ​​the material accumulation in the kiln, f is the friction coefficient, γ is the radius of the supporting roller journal, G is the sum of the mass of the rotating part of the kiln body plus the mass of all the supporting rollers and shafts, D is the outer diameter of the wheel band, d is the diameter of the tugboat, and K is the reserve coefficient.

4. The energy optimization control method for cement production process according to claim 2 is characterized in that: The calculation formula of belt conveyor motor power is as follows: Among them, N 电 is the belt conveyor motor power, K1LV represents the no-load running power of the conveyor; K2QL represents the power for horizontal material conveying; QH represents the power for vertical material lifting; K a is the power safety factor and full-load start-up factor, K3 is the factor related to the horizontal projection length of the conveyor, and K4 is the factor related to the layout of the conveyor; η P represents the total transmission efficiency of the belt conveyor motor; ξ is the material conveying coefficient; N sa Indicates the total operating power of the belt conveyor motor.

5. The energy optimization control method for cement production process according to claim 2 is characterized in that: The power calculation formula of the mill is as follows: Where, N0 is the power of the mill; V is the effective volume of the mill; D0 is the effective inner diameter of the mill; n g G is the working speed of the mill; Y is the grinding body loading.

6. The energy optimization control method for cement production process according to claim 1, characterized in that: In step 2, the construction formula of the energy optimization control model of the cement production process considering the interruptibility of load is as follows: Among them, C L Indicates rush work cost; minC L Indicates the minimum value of rush work cost; x i The flag indicating whether process i is interrupted or not, x i When it is 0, it means that process i is not interrupted, x i When it is 1, it means that process i is interrupted; T mi represents the minimum advance notice time, T represents the actual advance notice time, Δt mi represents the maximum interruption time of process i, Δt represents the actual interruption time, S l Indicates the actual load interruption capacity, L m represents the minimum load interruption capacity, t p0i Indicates the start time of rush work for process i, T fi It represents the transferable time interval of process i.

7. The energy optimization control method for cement production process according to claim 6, characterized in that: Cost of rush work C L The calculation formula is as follows: C L =C gd +C gud ; Among them, C gd represents the direct cost of rush work, C gud Represents the indirect cost of rush work.

8. The energy optimization control method for cement production process according to claim 6 is characterized by: Direct cost of rush work C gd The calculation formula is as follows: Among them, T pe Indicates rush time, t po Indicates the start time of rush work; t lo represents the interruption start time, Δt represents the interruption duration, C L (t) represents the total cost of interruptible load, C E (t) represents the unit electricity cost, W represents the manufacturing cost allocated per unit time, P l Indicates the interrupted load power, n pe Indicates the number of workers required for the rush process.

9. The energy optimization control method for cement production process according to claim 6, characterized in that: Indirect cost of rush work C gud The calculation formula is as follows: C gud =C B +C O +C C +Q4+Q5; Among them, C B represents the waste loss, C O represents the start-stop cost, C C represents the carbon emission cost in the cement production process, Q4 represents the profit lost due to reduced production, and Q5 represents the profit loss due to increased defective products.

10. The energy optimization control method for cement production process according to claim 1, characterized in that: In step 3, the formula for constructing the uncertainty set is as follows: In the formula, U represents the box type uncertainty set, N T represents the scheduling period, represents the predicted value of photovoltaic output during period t, represents the predicted value of load power in period t, u PV (t) and u L (t) is the uncertain variable of photovoltaic output and load power; and is the maximum fluctuation deviation allowed for the two.

11. The energy optimization control method for cement production process according to claim 1, characterized in that: In step 4, the construction formula of the two-stage robust optimization model is as follows: Where c is the coefficient column vector; D, K, F, G and I u is the coefficient matrix; d and h are constant column vectors, and x, u and y are all optimization variables; is the predicted value of the uncertain variable; the outer minimization is the first-stage problem, which means minimizing the interruptible cost; the inner maximization is the second-stage problem, and Ω(x,u) is the feasible domain of the variable y.

12. An energy optimization control system for a cement production process using the method according to any one of claims 1 to 11, comprising a load characteristic model building module, an energy optimization control model building module, a parameter acquisition module and a robust optimization model building module, characterized in that: Load characteristic model building module, used to build load characteristic models of various equipment in cement production process; Energy optimization control model building module, based on the established load characteristic model, builds an energy optimization control model for the cement production process that takes load interruptibility into account; The parameter acquisition module is used to obtain the photovoltaic output and load power in the cement production process and build an uncertainty set based on the acquired data; The robust optimization model building module constructs a two-stage robust optimization model based on the established energy optimization control model and the obtained photovoltaic output and load power to obtain the optimized interruption cost and rush time of the cement plant's interruptible equipment.

13. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-11.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

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