Method of batching and scheduling for steelmaking production with plant-wide process consideration

Patent metadata

Field	Value
Publication number	US-2017316131-A1
Application number	US-201615529745-A
Country	US
Kind code	A1
Filing date	Nov 14, 2016
Priority date	Nov 23, 2015
Publication date	Nov 2, 2017
Grant date	—

Abstract

Provided is a method of batching and scheduling for steelmaking production with plant-wide process consideration, including the steps of: establishing a mathematical model for quantitatively describing the decision problem of batching on steelmaking and continuous casting procedures; starting from the production capacity balance between parallel equipment of the same procedure, and material flow convergence between upstream and downstream procedures, establishing a model for the assignment and sequencing of batches on continuous casting equipment and the time dimension; integrating the batching plan and the production scheduling scheme, issuing the batching plan and the production scheduling scheme integrated to all production and manufacturing units at the steelmaking stage. The present invention improves product quality, increases the material yield, resource utilization rate and equipment operation efficiency, realizes load balance on parallel equipment and smooth material linkage between serial equipment, and reduces the material flow transportation jam, downstream equipment waiting time and inventory.

First claim

What is claimed is:

1 . A method of batching and scheduling for steelmaking production with plant-wide process consideration, comprising the following steps of:
step 1, describing a production environment by constructing a directed topological network, wherein each node on the directed topological network represents a specific production unit or inventory equipment, including: a converter, a refining furnace, a continuous caster, a slab warehouse, a hot rolling mill, a temper mill, a hot-rolled coil warehouse, an acid pickling unit and an acid rolling mill; each arc on the directed topological network represents a specific material transfer course from one unit or inventory equipment to another unit or inventory equipment, including: molten steel, slabs, hot-rolled coils and cold-rolled coils; step 2, according to quality requirements for finished products by different customers' orders, setting product process parameters, comprising: determining the mapping of a product manufacturing process in the directed topological network, calculating casting width ranges of different products in the continuous caster according to steel grades, determining the upgrade relationship between different steel grades, and determining the casting with steel grade change and cost of different types of steel in tundishes; step 3, determining groups to which product orders belong according to the steel grades, categories, optional manufacturing process and width ranges of the products required by customers' orders, wherein if the sum of unfulfilled quantities for all orders required by the customer is greater than or equal to the maximum number of allowed process continuous casting heats of the tundishes, such customer's order belongs to a subset of large orders, and performing step 6; if the sum of unfulfilled quantities for all orders required by the customer is smaller than the maximum number of allowed process continuous casting heats of the tundishes, such customer's order belongs to a subset of small orders, and performing step 4 to step 5; step 4, describing the batching production decision of multiple products in the steelmaking procedure by constructing a mathematical model, comprising the following steps of: step 4-1, mapping a multi-product batching scheme in the steelmaking production course into decision variables for the mathematical model; step 4-2, mapping process limits for the steelmaking production course into constraint conditions for the mathematical model, comprising the following steps of: step 4-2-1, establishing process constraints for substitution relationship of the product steel grades; step 4-2-2, establishing process constraints for the casting width ranges of the products on continuous casting equipment; step 4-2-3, establishing process constraints for smelting capacity limit of each batch of the converter, namely, requiring that the total weight of the slabs required by the customers' orders and open-ordered slabs limited within the same batch of smelting needs to be close to standard smelting capacity of the converter, and the weight of a part beyond the standard smelting capacity of the converter and that below standard smelting capacity of the converter need to be both less than the weight of one slab, the open-ordered slabs are surplus materials produced to satisfy the full capacity of converter during smelting course but not assigned to any customers' orders; step 4-2-4, establishing process constraints for balancing on two strands so as to synchronize the consumptions of molten steel of two strands during casting of each furnace of molten steel on the continuous caster, namely, requiring that casting times of two strands of the same furnace of molten steel on the continuous caster need to be equal to each other, which is mapped on the model as equal number of slabs cast from the two strands; step 4-2-5, establishing process constraints for cutting length ranges of the slabs on the continuous casting equipment, namely, under limits by the cutting process of the continuous caster and length ordered by customers, requiring that the lengths of any slabs cast from one furnace of molten steel need to be within a specified range; and step 4-2-6, constructing flexible management constraints for customers' order quantities, namely, requiring that the part below or beyond the customers' order quantities needs to be less than the weight of one slab; step 4-3, mapping optimized process indicators during a steelmaking production course into an objective function of the mathematical model, to minimize the total weight of the open-ordered slabs output from all batches, minimize the upgrade quantity between different steel grades, minimize the total deviation quantity between the weight of slabs produced in all batches and the standard smelting capacity of the converter, and minimize the total deviation number of quantities ordered by all customers' orders; step 5, constructing a mutual mapping relationship between a real matrix and the batching scheme, and using the established real matrix as a controlled object to obtain a final optimization batching scheme based on a multi-object parallel iterative improvement strategy, and then to obtain a pre-batching scheme of the subset of small orders in the continuous casting procedure, comprising the following steps of: step 5-1, constructing a mutual mapping relationship between the real matrix and the batching scheme, comprising the following steps of: step 5-1-1, constructing a real matrix, wherein the dimension of the real matrix is a product of a total product number, the steel grade and the width of all products, and an element in the matrix is a ratio of the weight of the slabs assigned to a certain steel grade and a certain width by a certain order to the order unfulfilled quantity; step 5-1-2, obtaining the weight of the slabs with the objective steel grade and the objective width, in all batches, set in a certain order, and the weight of the slabs with the objective steel grade and the objective width, in all batches, sequencing (from large to small) all combinations of the steel grades and widths according to the weight values of all ordered slabs in all batches, and repeating steps 5-1-3 to 5-1-9 in the sequence; step 5-1-3, determining weight vectors of slabs with any combinations of steel grades and widths set by all the orders, constructing an empty batch, and setting the weight of slabs contained in the empty batch to be 0; step 5-1-4, selecting one order with a first slab of which the weight is greater than 0 from the slab weight vectors, and comparing the remaining capacity of the empty batch with the size of the first slab weight; if the remaining capacity is greater than or equal to the weight of the first slabs, performing step 5-1-5, or else performing step 5-1-6; step 5-1-5, replacing the unfulfilled quantity of a corresponding product in the flexible management constraint conditions for customers' order quantities with the slab weight of the product, obtaining an integer number of slabs according to the process conditions set forth in steps 4-2-5 to 4-2-6, putting the slabs in the empty batch, updating the slab weight of the batch and setting the slab weight of the product in the slab weight vectors to be 0; step 5-1-6, replacing the unfulfilled quantity of a corresponding product in the flexible management constraint conditions for customers' order quantities with the remaining capacity, obtaining an integer number of slabs according to the process conditions set forth in steps 4-2-5 to 4-2-6, putting the slabs in the empty batch, updating the slab weight of the batch and setting the slab weight of the product in the slab weight vectors to be 0; step 5-1-7, in the absence of the addition of open-ordered slabs, judging whether the slabs contained in the empty batch meet the process constraint conditions limited by the

Assignees

• Univ Northeastern

Inventors

• Tang li xin
• WANG Gong shu
• Xu wen jie

Classifications

• G06F30/20 Primary

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• Y02P90/30

  Computing systems specially adapted for manufacturing · CPC title

• G06F2111/10

  Numerical modelling · CPC title

• C21C5/5294

  General arrangement or layout of the electric melt shop · CPC title

• G06Q10/0631 Primary

  Resource planning, allocation, distributing or scheduling for enterprises or organisations · CPC title