Simulation and Optimization of the Steel Enterprise Raw Material System
Lin-wei Xu1, Pei-qing Wang2, Shang-lun Chen2, Xing-li Zhong2
(1. CISDI Chongqing Iron & Steelmaking Plant Integration Co., Ltd., Chongqing, 400013;
2. logistics Department, CISDI Engineering Co., Ltd., Chongqing, 400013)
Abstract - This paper uses discrete system simulation
method to simulate the production scheduling material
factory, verify the feasibility of the material factory system
design , find out the system weakness, optimize the design
and scheduling schemes, save investment, reduce the cost of
operation. With the understanding of production and
operation in detailed, we use system simulation to build
material factory simulation model, the system simulation not
only provides a powerful data analysis, and supports virtual
reality 3D animation. On the optimization problem of belt
conveyor route, we compare the A * algorithm and depthfirst recursion algorithm, the best algorithm was obtained.
About the yard optimization problem, we use unfixed type
and variable tonnage stock pile, and use search mechanism
to dispatch belt conveyor route and reclaimer, combining
Optimization module to optimize the yard. At the same time
we can get the input of coal field to formulate purchase plan.
each other, and it is a typical of random discrete event
system, Mathematical analytical method cannot give a
comprehensive analysis and optimization. Thus the
current design often uses empirical coefficient method. In
order to avoid wasting a lot manpower, material and time,
system simulation is the inevitable choice to support and
optimize design. The system simulation allows us to
observe the dynamic change of the system model, identify
bottlenecks, modified parameters repeatedly and find the
best parameters, and then optimize the performance of the
entire system. The system simulation of material factory
makes us to accurately evaluate the quality of the design
in its planning stage, improve the reliability of the actual
production, and achieve better social and economic
benefits, at the same time, we can simulate various
scheduling schemes to optimize the inventory of the
material factory and guide the production.
Keywords - Materials factory, simulation, optimization
II. MATERIAL FACTORY SYSTEM DESIGN
I. INTRODUCTION
With
the
further
adjustment
of
China's
steel industry structure,
steel
enterprises gradually
develop to be large-scale; the delivery and storage
capacity of the material factory has become one of the
bottlenecks which restrict the production scale. The major
domestic steel enterprises have risen a new turn of energy
saving and emission reduction and eliminate backward
production capacity. Further optimizing design which
aims to improve the production capacity of material
factory is in research and practice. With the social
economic development, the land resources are becoming
more and more expensive, steel enterprises can not
expand its area of material factory indefinitely. With
limited resources how to optimize design, explore the
potential, and improve the production capacity of material
factory is a common problem for all designers of raw
material plant. Simply increasing the investment to
expand raw material scale can increase its production
capacity, but apparently it isn’t the economic way;
Compression investment, streamline processes, improve
the efficiency of equipment and explore production
capacity is also exposed to the risk of insufficient
capacity. We need an accurate evaluation method that can
give quantitative data to balance the two sides and provide
the useful data for the decision-making[1-3].
Material factory has much equipment, scattered
layout, complex process and its subsystem intersect with
This paper simulate a typical coal yard where store
eight kinds of coking coal, two kinds of thermal coal, two
kinds of blind coal and three kinds of injecting Mixed
Coal. There are A、B、C、D four material strip feeder.
Each material strip feeder has a track bed with two
bucket-wheel stacker reclaimer above it.
（1）Input system
The input system mainly including the pier and the
rail car dumper input system. The main raw
material is transported from the sea to the pier and then
transported into the material factory through belt
conveyor, the other material unload by the train car
dumper and then transported by the belt conveyor too.
The pier input system designed to one conveyor line. The
rail input system consists of car dumper and relevant
delivery system that designed to two lines.
（2）Output system
The coking coal output system is designed to two
lines that mainly transported coking coal from coal yard
to coking coal blending bunker, transported blind coal
from coal yard to sintering blending bunker and
transported injecting mixed coal from coal yard to the
blast furnace injection blending bunkers. The thermal coal
output system is designed to one line that mainly
transported thermal coal from coal yard to power plant.
The blast furnace output system and the coking coal
output system use the same transport lines.
III．EQUIPMENT OF THE MATERIAL FACTORY
AND SIMULATION MODULE
Establish each simulation module and the simulation
model shown in Figure 1. In the following section this
paper will introduce various equipment and simulation
module
Figure. 1. The simulation model diagram
（1）The Belt conveyor module
The belt conveyor is a material handing machine that
continuous transfer material in a certain line, also known
as a tape machine. Belt conveyor can be horizontal, tilt
and vertical transport, the space can also be composed of
transport lines, transport lines are generally fixed. Belt
conveyor transport capacity, long distance, but also in the
transportation process of a number of processes operating
at the same time, so a wide range of applications. The
simulation software has a standard fixed belt conveyor
module, so set the parameters then can use it.
（2）The Stacker-reclaimer module
The stacker-reclaimer is are widely used in building
materials, mining, coal, power, metallurgical, chemical,
cement and other industries. Because of there is no
corresponding standard module in the software, so this
module need to completely customize. The stackerreclaimer movement is very complex, it not only walk,
rotate arm, but also the bucket wheel need to be rotated,
so the stacker-reclaimer need to customize a variety of
kinematics, Import 3D models, the module shown in
Figure 2.
Figure. 2. Stacker and reclaimer
（4）The Bunker module
There are a variety of bunkers to provide raw
material for the production system in the raw material
system, it is the end for the transport system, but for the
production
it
is
the
beginning.
Each bunker consumption rates and demand are not the
same. The bunker that contains a lot of codes is a Satellite
control centre in simulation system. The bunker will call
the belt conveyor line and scheduling module of stackerreclaimer according to the level of the material. Central
control module will determine the task priority. Finally,
the bunker module appoints belt conveyor line and
stacker-reclaimer. Then the belt conveyor line and
stacker-reclaimer finish the task.
（5）The Coal pile module
Coalpile is the most important module in the simulation
model and the amount of code it contains is also the
largest, because it is not only required the coal but also
the supplier, so it is not only an active judgment entity but
also a passive entity. When it is in the active state, it sends
a message to the port module or railway station module.
Then it will call the belt conveyor and stacker-reclaime,
and then the module will call the central control module
to determine the task priority, finally finishes the transport
task. When it is in a passive state, it only receives the
message sent by the central control module to tell which
bunker does the coal send to. Its three-dimensional entity
shows in Figure 3.
Figure. 3. The coal pile simulation module
（6） The central control module
The role of this module is to determine which task
execute first based on task priority parameters, it can be a
no-display graphical entity; the other is the interrupt
module, its role is mainly to interrupt the non-critical
tasks to free the resource, the freed resource will meet the
emergence situation based on the number of interrupt
within a certain time.
4．OPTIMIZATION OF THE MATERIAL FACTORY
（1）Belt conveyor route optimization
The belt conveyor route is very complex; there are a
lot of transfer stations. Some of the transfer station
between the belt conveyors is for several belt conveyor
routes, so there is not only one belt conveyor route from
one operating point to another, therefore it is necessary to
determine which is the shortest route. Although there are
some routes in the simulation process, but if one or a few
belt conveyor of some routes has been occupied, so we
must call the shortest route based on the available route
situation. The shortest path algorithm is Dijkstra
algorithm, A*(A start) algorithm, depth-first algorithm.
Dijkstra algorithm is A* algorithm of the special case,
also is the lowest efficiency case. If we just need to find a
path, depth-first algorithm can quickly find out the route
and jump out of the circulation; however, if we search
for all the routes, and then compare all the paths, so the
efficiency is very low. In the simulation model, each task
need to call the search path algorithm, so if the shortest
path algorithm efficiency is low, which will affect
the simulation speed. A * algorithm is actually a heuristic
search[4-8]; A * algorithm uses a best-first search and finds
a least-cost path from a given initial node to one goal
node. It uses a distance-plus-cost heuristic function to
determine the order in which the search visits nodes in the
tree. The A* can be implemented more efficiently—
roughly speaking, no node needs to be processed more
than once[9-10]. If we use general function to package the
A*, we call this function then we can get a belt convey or
route. As shown in Figure 5, through this route table, the
coal entities can reach its destination.
Figure. 5. Tape machine route table
（2）Storage yard optimization
Each strip feeder has a certain amount of stock pile,
in order to optimize, each stock pile set a unique number
and tonnage, if the consumer want to find the right stock
pile by the unique number, so it must search the storage
yard module. In other words, we can change the unique
number and tonnage of each stock pile in storage yard
module, that mean the stock pile martial changed. By set
the unique number constraints and tonnage constraint and
the objective function in the optimize module, run the
simulation we can get the best storage layout. As shown
in Figure 6.
can find out system defects and reduce redundant
equipment to reduce costs.
TABLE I
A PART OF UTIILIZATION OF TAPE MACHINE
convey
idle
blocked
conveying
G303_BW1400
35.54%
0.00%
64.46%
G304SHR_BW1400
35.84%
0.00%
64.16%
B304_BW1600
37.60%
0.00%
62.40%
B302_BW1600
39.19%
0.00%
60.81%
G104_BW1600
40.43%
0.00%
59.57%
G102_BW1600
40.61%
0.00%
59.39%
G103SHR_BW1800
40.61%
0.00%
59.39%
G101_BW1600
40.62%
0.00%
59.38%
B305SHR_BW1800
38.23%
0.00%
58.40%
P131_BW1200
41.84%
0.00%
58.16%
P207_BW1200
41.86%
0.00%
58.14%
P205_BW1200
42.60%
0.00%
57.40%
P107_BW1200
42.63%
0.00%
57.37%
P108SHR_BW1400
42.68%
0.00%
57.32%
P206SHR_BW1400
42.68%
0.00%
57.32%
P203_BW1200
42.72%
0.00%
57.28%
P105_BW1200
42.74%
0.00%
57.26%
P204R_BW1200
43.16%
0.00%
56.84%
We can also get the maximum, minimum and
average inventory of each bunker and stock pile. At the
same time, so we can get minimum safe stock to reduce
the costs.
TABLE II
INVENTORY OF COAL PILE
Object
minimum
inventory
maximum
inventory
average
inventory
stock pile b1
33162
33600
33212.87
stock pile b2
24741
25200
25016.22
stock pile b3
23934
25200
24613.88
stock pile b4
32731
33600
33315.41
stock pile b5
24365
25200
24759.07
stock pile b6
24141
25200
24653.88
stock pile b7
33037
33600
33362.62
stock pile b8
22921
25200
24187.45
stock pile b9
24611
25200
24858
stock pile c1
14235
15150
14667.43
stock pile c2
17346
18225
17796.27
stock pile c3
10314
11175
10849.64
stock pile c4
10727
11175
11011.88
stock pile c5
15150
15150
15150
stock pile c6
5438
5625
5607.377
stock pile c7
10713
11175
10934.45
Figure. 6. Stock pile layout optimization table
5．SIMULATION RESULTS AND CONCLUSIONS
By way of simulation we can get the utilization of all
kinds of equipment, as shown in Table 1, by analyzing
utilization of the equipment, we can find out the
bottlenecks and redundancy of the system, and then we
TABLE II
INVENTORY OF COAL PILE
stock pile d1
5439
5625
5566.625
stock pile d2
5225
5700
5505.055
stock pile d3
10307
11175
10774.34
stock pile d4
11175
11175
11175
stock pile d5
13827
15150
14468.55
stock pile d6
10345
11175
10790.21
stock pile d7
10724
11175
10918.79
stock pile d8
9843
11175
10619.38
Get the input information of the storage yard by
ways of simulation is earlier to make procurement plan.
Management staff can make out the corresponding
purchasing transport plan. Table3 is input information of
the storage yard。
TABLE III
INPUT OF STORAGE YARD
Begin time
End time
type
quantity
delivered
source
204493.9498
213501.039
5
3000
railway
229834.1575
238175.9075
8
5000
ship
239054.1902
247395.9402
2
5000
ship
310582.79
319589.8792
1
3000
railway
364302.9018
380978.0684
7
10000
ship
396078.4561
404420.2061
3
5000
ship
485135.0921
494142.1813
1
3000
railway
Finally by means of using simulation technology we
can make quantitative evaluation and analysis of the
material factory and optimize the design and scheduling.
This paper also showed that we can use simulation
technology to establish the random complex large
production scheduling system model. If we change the
Parameters and strategy, we can get the simulation results
quickly, and by using optimization function of simulation
software, we can get the optimal configuration of the
system resources.
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