A method for calculating the effective fuel consumption per unit area of ​​a continuous industrial heating furnace.

Abstract

This invention relates to a method for calculating the effective fuel consumption per unit area of ​​a continuous industrial heating furnace, belonging to the field of metallurgical technology. The method calculates the ineffective heating state of the furnace by using parameters such as the furnace's production status and the surface heat flux density of the material, then calculates the fuel consumption during the ineffective heating period, and finally calculates the effective fuel consumption per unit area of ​​the furnace. This invention divides the furnace's production process into two scenarios: effective heating and ineffective heating. First, the fuel consumption during ineffective heating is calculated, then the effective fuel consumption per unit area is calculated. By comparing the total fuel consumption per unit area and the effective fuel consumption per unit area longitudinally, the impact of production contingencies such as planned production scheduling and upstream / downstream process matching on fuel consumption can be assessed. By comparing the effective fuel consumption per unit area under different processes, different shifts, and different heating furnaces laterally, production processes can be optimized, shift operational levels can be evaluated, and the industry technical level of the heating furnace can be assessed.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology and relates to a method for calculating the effective fuel consumption per unit area of ​​a continuous industrial heating furnace. Background Technology

[0002] Continuous industrial heating furnaces are large-scale industrial heating devices that continuously load and discharge materials during the production process, with materials constantly moving from the loading end to the discharging end within the furnace. Due to the uninterrupted nature of production, they are characterized by high output and high energy consumption, making them major energy consumers in factories. Accurately calculating the unit consumption in this process helps in the analysis and optimization of production costs, production management, and production processes, thereby achieving the goals of energy conservation, emission reduction, and carbon reduction.

[0003] Industrial heating furnace processes typically calculate unit energy consumption by dividing the cumulative fuel consumption over the production cycle by the output. While this method is convenient, it only reflects overall cost factors and lacks an assessment of the impact of adverse energy consumption factors, making cross-sectional comparisons impossible. For example, in a steel mill's hot rolling workshop, heating furnace production is frequently interrupted due to equipment maintenance or mill malfunctions, leading to increased unit energy consumption. The conventional method used to calculate unit energy consumption fails to exclude fuel consumption during production interruptions, making it difficult to accurately assess the impact of these interruptions on energy consumption. Furthermore, it's challenging to accurately use heating furnace unit energy consumption for team evaluations or industry-wide comparisons. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for calculating the effective fuel consumption per unit area of ​​a continuous industrial heating furnace.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention first calculates the ineffective heating state of the furnace, then calculates the fuel consumption under the ineffective heating state, and finally calculates the effective fuel consumption per unit area. (See attached diagram) Figure 1 As shown, the entire calculation process of this invention includes five parallel calculation processes, of which (1) the main process calculates the effective fuel consumption and total fuel consumption, including data initialization, effective fuel consumption calculation and production statistical cycle loop, and the main parameters required for its calculation are provided by sub-process 4; (2) when a charging and discharging production event occurs, sub-process 1 calculates the effective production change time of the material; (3) when a displacement event occurs in the furnace, sub-process 2 calculates the effectiveness of the displacement and the effective production change time of the material; (4) sub-process 3 calculates and records the average heat flux density on the surface of the material; (5) based on the parameters provided by sub-processes 1 to 3, sub-process 4 calculates whether the heating furnace is in an ineffective heating state, as well as the total fuel consumption and ineffective fuel consumption within the statistical cycle.

[0007] The algorithm described in the technical solution of this invention includes the following steps:

[0008] 1. Initialize the amount of invalid heating fuel Q in the current statistical period. inv The total fuel consumption is zero, Q. t It is zero, that is

[0009] Q inv =Q t =0 (1)

[0010] Where, Δt sta Based on statistical needs, it can be equal to the working hours per shift, or 24 hours, etc.

[0011] 2. Based on the action events of the material loading and unloading device, update the most recent effective material production change time t1. That is, when the heating furnace loading or unloading is completed, perform the following calculations:

[0012] t1=t now (2)

[0013] In the above formula, the subscript "now" indicates the current time.

[0014] 3. Record the displacement state of the material in the furnace and calculate the production effectiveness of the displacement.

[0015] Each time a material moves forward or backward, the displacement distance l of the material is recorded. 2,i and the time of occurrence t 2,i The subscript i represents the sequence number of the record point in the record linked list (sorted by time).

[0016] When the material retreats, only a record is made; at this time, l 2,i Less than zero.

[0017] When the material moves forward, l 2,i Greater than zero. After recording, a judgment is made: if the material advances twice consecutively within the specified time interval Δt2, it is considered that the material has generated a valid displacement, and t1 is refreshed to the current time. That is, if...

[0018] t 2,i -t 2,i-1 ≤Δt2 and l 2,i-1 >0 and l 2,i >0 (3)

[0019] Then t1 = t now (2)

[0020] The time interval judgment in (Equation 3) is to prevent misjudgment caused by a long pause followed by a return to the same position. If the material displacement records show a backward movement in the last two records, it is considered that the material is in an unexpected production retreat or a "stepping" state to ensure uniform heating, and there is no need to refresh the t1 time.

[0021] Based on steps 2 and 3, equations (2) and (3) can be combined into the following equation:

[0022]

[0023] In the above formula, t now The time when a loading, unloading, or material displacement event occurs, to distinguish between the upper and lower t. now It is not the same value; different numbers are deliberately added after the subscript "now".

[0024] 4. Periodically calculate and record the heat flux density between the material and the furnace using the furnace mathematical model program. If the furnace does not have a mathematical model to calculate the material temperature, step 4 can be skipped.

[0025] If the material is in block form, it is directly numbered 1, 2, ... j ... n; if the material is in bulk form, it is divided into n equal parts along the length of the furnace, and each part is also numbered 1, 2, ... j ... n.

[0026] Record the average surface heat flux density q of material j at time t3. 3,j The subscript j indicates the material number.

[0027] 5. Periodically record the cumulative fuel consumption of the heating furnace, determine whether it is in an effective heating state, and calculate the fuel consumption for ineffective heating.

[0028] At time t4 of the i-th fuel consumption recording period:

[0029] Record the current time t 4,i Cumulative fuel consumption Q of heating furnace cu,i ;

[0030] The total fuel consumption for the current production statistical period is the sum of the previous value and the current consumption.

[0031] Q t =Q t，old +(Q cu，i +Q cu，i-1 (4)

[0032] Determine whether the heating is ineffective and calculate the amount of fuel used for ineffective heating.

[0033] If no material is loaded or unloaded within a time interval Δt4, and the material does not undergo effective displacement within the furnace, then a production accident is considered to have occurred. That is, the condition is met.

[0034] t now -t1≥Δt4 (Equation 5)

[0035] The condition formula (5) is called the production accident condition, and Δt4 is called the production accident judgment time.

[0036] The calculation methods for ineffective heating fuel consumption can be divided into two cases: with or without a heating furnace and without a mathematical model.

[0037] (a) The heating furnace does not have a mathematical model to calculate the material temperature. Ineffective heating is calculated based solely on production conditions.

[0038] To prevent misjudgment, Δt4 is usually defined conservatively with a longer time frame when no model is available. When the condition in formula (5) is met, the material is already in an ineffective heating or overheated state. Δt′4 is defined as the ineffective heating time traced back (Δt′4 should be less than Δt4), at t 4，i The linked list of records is used to find the starting point t of invalid heating time. 4，p ,due:

[0039] (t now -t 4，p )-Δt′4≈0

[0040] The left-hand side of the above equation is equivalent to subtracting t from the current recorded time. 4，i At a certain moment in the linked list, subtract Δt′4, and take the smallest absolute value from the series of differences obtained, i.e.

[0041]

[0042] In the above formula, the subscript p indicates that the recording point is in the fuel cumulative consumption recording linked list t. 4，i The serial numbers that meet condition (6) in (sorted by time).

[0043] Get the relationship with t from the linked list. 4，p The cumulative fuel consumption Q at time 1 cu，p The amount of ineffective heating fuel used is then traced back to:

[0044] Q inv，0 =Q cu，i -Q cu，p (7)

[0045] The amount of ineffective heating fuel used in the current production statistical period needs to be added to the amount of ineffective fuel used retrospectively.

[0046] Q inv =Q inv，old +Q inv，0 =Q inv，old +(Q cu，i -Q cu，p (8)

[0047] Subsequently, each fuel cumulative consumption recording period t 4，iAt any given time, if unexpected production conditions are met, the heating furnace is in an ineffective heating state, and the amount of ineffective fuel consumption is added to the fuel consumption for the current cycle each time.

[0048] Q inv =Q inv，old +(Q cu，i -Q cu，i-1 (9)

[0049] (b) The heating furnace has a mathematical model to calculate the material temperature. Ineffective heating is calculated based on both production conditions and the heat absorption of the material, resulting in more accurate results.

[0050] The material is defined as being in an ineffective heating state when the average heat flux density on the surface of the material is less than q0. When the proportion of material in the heating furnace in an ineffective heating state reaches a certain threshold... Furthermore, when production unexpected conditions (5) are met simultaneously, the heating furnace is in an ineffective heating state.

[0051] Right now

[0052]

[0053] In the above formula, j is the material number in the heating furnace, j = 1, 2, ..., n; n is the total number of materials in the heating furnace at present. α j α is the ineffective heating factor for the material. j =1 indicates that the material is currently in an ineffective heating state.

[0054] If the conditions are met

[0055]

[0056] If unexpected production conditions are met, the furnace is in an ineffective heating state. In this case, the fuel consumption for ineffective heating is added to the fuel consumption for the current cycle each time.

[0057] Q inv =Q inv，old +(Q cu，i -Q cu，i-1 (9)

[0058] 6. Production statistical cycle Δt sta If the output of the material at the end is P, then the effective fuel consumption per unit area of ​​the heating furnace is calculated as follows:

[0059]

[0060] The total fuel consumption per unit area of ​​the heating furnace obtained by conventional statistical methods is:

[0061]

[0062] 7. Return to step 1, and a new production statistics cycle will begin.

[0063] The beneficial effects of this invention are as follows: This invention divides the production process of the heating furnace into two cases: effective heating and ineffective heating. First, it calculates the fuel consumption during ineffective heating, and then calculates the effective fuel consumption per unit area. By comparing the total fuel consumption per unit area and the effective fuel consumption per unit area longitudinally, the impact of unexpected production factors such as planned production scheduling and upstream / downstream process matching on fuel consumption per unit area can be assessed. By comparing the effective fuel consumption per unit area under different processes, different work groups, and different heating furnaces laterally, production processes can be optimized, work group operational levels can be assessed, and the industry technical level of the heating furnace can be evaluated.

[0064] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0065] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0066] Figure 1 This is a flowchart for calculating effective fuel consumption per unit area within a production cycle. Detailed Implementation

[0067] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0068] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0069] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0070] The computation process of this invention includes five parallel computation flows, wherein

[0071] 1. Calculate effective fuel consumption and total fuel consumption, including data initialization, effective fuel consumption calculation and production statistical cycle loop. The main parameters required for the calculation are provided by sub-process 4.

[0072] 2. Sub-process 1 calculates the effective production change time of materials when loading and unloading production events occur;

[0073] 3. When a material displacement event occurs in the furnace, subprocess 2 calculates the validity of the displacement and the effective production change time of the material.

[0074] 4. Sub-process 3: Calculate and record the average heat flux density on the material surface;

[0075] 5. Subprocess 4 calculates whether the heating furnace is in an ineffective heating state based on the parameters provided by subprocesses 1 to 3, as well as the total fuel consumption and ineffective fuel consumption within the statistical period.

[0076] The following example uses the daily production statistics of a hot rolling walking beam reheating furnace in a steel plant to calculate the effective fuel consumption per unit day of the reheating furnace.

[0077] 1. At midnight each day, the ineffective heating fuel consumption Q of the heating furnace is recorded. inv Total fuel consumption Q t All are reset to zero, that is

[0078] Q inv =Q t =0

[0079] 2. After the heating furnace has completed the steel loading or unloading process, the effective production change time t1 is updated to the current time.

[0080] t1=t now

[0081] 3. After the walking beam of the heating furnace completes its forward or backward movement, record the stepping distance l of the walking beam. 2,iand the time of occurrence t 2,i .

[0082] (1) When the walking beam retracts, only records are made. At this time, l 2,i Less than zero.

[0083] (2) When the stepping beam moves forward, l 2，i Greater than zero. After recording, a judgment is made: if the stepping beam advances twice consecutively within the specified time interval Δt2, it is considered that the material has generated effective displacement, and t1 is refreshed to the current time, as shown in equation (1). That is, if

[0084] t 2，i -t 2，i-1 ≤Δt2 and l 2，i-1 >0 and l 2，i >0

[0085] but

[0086] t1=t now

[0087] If the stepper beam has moved backward in the last two steps, there is no need to refresh time t1.

[0088] 4. Every minute (this period can be varied according to actual needs), the secondary model of the heating furnace periodically calculates the heat flux density q on the surface of the steel billet. 3，j The data is then stored in a linked list or database, with the index j representing the number of the steel billet in the furnace, j = 1, 2, ..., n. If the heating furnace does not have a mathematical model to calculate the material temperature, step 4 can be skipped.

[0089] 5. Every minute (this cycle can be changed according to actual needs), periodically record the cumulative fuel consumption of the heating furnace, determine whether it is in an effective heating state, and calculate the fuel consumption of ineffective heating.

[0090] At time t4 of the i-th fuel consumption recording period:

[0091] (1) Record the current time t 4，i Cumulative fuel consumption Q of heating furnace cu，i ;

[0092] The total fuel consumption for the day is the sum of the previous value and the consumption for this minute:

[0093] Q t =Q t，old +(Q cu，i +Q cu，i-1 )

[0094] (2) Determine whether it is in an ineffective heating state and calculate the amount of fuel used for ineffective heating.

[0095] If no steel is loaded and the walking beam does not advance effectively within the time interval Δt4, it is determined that a production accident has occurred. That is, the condition is met.

[0096] t now -t1≥Δt4

[0097] When an accident occurs during production, the above formula is also known as a production accident condition.

[0098] The calculation of ineffective heating fuel consumption can be divided into the following two cases:

[0099] (a) The heating furnace does not have an L2 model to calculate the material temperature.

[0100] To prevent misjudgment, the time Δt4 is usually defined conservatively, ensuring that the material is already in an ineffective or overheated state when unexpected production conditions are met. Therefore, the initial unexpected production conditions can be defined as starting from t... 4，i The time period Δt′4 (Δt′4 should be less than Δt4) before the start of invalid heating is calculated according to the following formula. 4，p :

[0101]

[0102] In the above formula, the subscript p indicates that the recording point is in the fuel cumulative consumption recording linked list t. 4，i The sequence number that meets the condition of equation (6) in (sorted by time).

[0103] Find the match t in the linked list 4，p The cumulative fuel consumption Q at time 1 cu，p The amount of invalid heating fuel used during retrospection is:

[0104] Q inv，0 =Q cu，i -Q cu，p

[0105] The invalid heating fuel consumption for that day is the previous value plus the retrospective invalid fuel consumption:

[0106] Q inv =Q inv，old +Q inv，0 =Q inv，old +(Q cu，i -Q cu，p )

[0107] Subsequently, whenever fuel consumption is recorded, any invalid fuel consumption should be added to the current cycle's fuel consumption if unexpected production conditions are met.

[0108] Q inv =Q inv，old +(Q cu，i -Qcu，i-1 )

[0109] (b) The heating furnace has an L2 model system to calculate the material temperature.

[0110] A billet is considered to be in an ineffective heating state when the average heat flux density on its surface is less than q0. When the proportion of billets in the heating furnace in an ineffective heating state reaches [a certain threshold], [further action is required]. Furthermore, when unexpected production conditions are simultaneously met, the heating furnace is in an ineffective heating state. That is, the calculation method for ineffective billet heating is as follows:

[0111]

[0112] In the above formula, j is the billet number in the heating furnace, j = 1, 2, ..., n; n is the total number of billets in the current heating furnace. α j =1 indicates that the billet is currently in an ineffective heating state.

[0113] According to the definition of invalid heating, if the following conditions are met:

[0114]

[0115] If unexpected production conditions are met, the furnace is in an ineffective heating state. In this case, the fuel consumption for ineffective heating is the sum of the previous value and the fuel consumption within this minute:

[0116] Q inv =Q inv，old +(Q cu，i -Q cu，i-1 )

[0117] 6. Assuming the material output at the end of the day is P, the effective fuel consumption per unit area of ​​the heating furnace can be calculated as follows:

[0118]

[0119] The total fuel consumption per unit area of ​​the heating furnace obtained by conventional statistical methods is:

[0120]

[0121] 7. Return to step 1 and continue calculating the effective fuel consumption per unit of the heating furnace for the next day.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for calculating the effective fuel consumption per unit area of ​​a continuous industrial heating furnace, characterized in that: The method is as follows: First, determine whether the heating furnace is in an ineffective heating state. Then, calculate the fuel consumption during ineffective heating. Finally, calculate the effective fuel consumption per unit area. The formula is as follows: All terms in the above formula represent data within the statistical period. This refers to the effective fuel consumption per unit of fuel in the heating furnace. This represents the total fuel consumption of the heating furnace; This refers to the fuel consumption when the furnace is in an ineffective heating state. P For the output of the heating furnace; The ineffective heating state of the heating furnace is related to the production state of the heating furnace, as shown in the following formula: In the above formula, This is the moment when the current production status of the heating furnace is determined. This refers to the most recent effective production change in materials; Time for determining production accidents; The effective production variation time of the material is related to the material's loading, unloading, and effective displacement within the heating furnace, as shown in the following formula: In the above formula, The moment when the loading or unloading event occurs; The moment when the material displacement occurs inside the heating furnace; The time of the most recent material displacement. The distance of the most recent displacement. This represents the distance of the previous displacement; Indicates the time interval threshold; When the heating furnace is in an ineffective heating state during production, the amount of ineffective fuel needs to be retrospectively calculated. The algorithm for the time starting point of the retrospective calculation is as follows: In the above formula, the subscript p This indicates the record point in the fuel cumulative consumption record linked list. t 4,i Sort by a specific sequence number based on time; k It can be any index in the linked list; Duration of invalid heating backtracking; In the i Sub-fuel consumption recording cycle t 4 moments: Record the current moment Cumulative fuel consumption of heating furnace ; The total fuel consumption for the current production statistical period is the sum of the previous value and the current consumption: in, Indicates the first i Recording moments Cumulative fuel consumption; Indicates the first i Cumulative fuel consumption at one recording point; This indicates the moment found using the backtracking algorithm. Cumulative fuel consumption; This represents the previous value of the total fuel consumption accumulated up to the last calculation within the current production statistical period; Get from the linked list Cumulative fuel consumption at any given time The amount of ineffective heating fuel used is then traced back to: Indicates the amount of invalid heating fuel used during retrospection; The amount of ineffective heating fuel used in the current production statistical period needs to be added to the amount of ineffective fuel used retrospectively: This represents the previous value of the cumulative amount of ineffective heating fuel used up to the last calculation within the current production statistical period. Subsequent fuel consumption recording periods At any given time, if unexpected production conditions are met, the heating furnace is in an ineffective heating state, and the amount of ineffective fuel consumption is added to the fuel consumption for the current cycle each time. The definition of the ineffective heating state of the furnace is related to the heat absorption state of the material inside the furnace; the algorithm is as follows: In the above formula, For materials j Average heat flux density of the surface; This is the lower limit of the ineffective heating heat flux density; This is an ineffective heating factor for the material; n This represents the total number of materials inside the heating furnace. This is the threshold for the proportion of materials that are not effectively heated in the heating furnace.

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