Design optimization of circulating water pump stat

2022-08-16
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Design optimization of BF circulating water pump station

Abstract: through summarizing the experience of operation of BF pump stations (eight pump stations, three pump stations, seven pump stations), the design of BF circulating water pump station is gradually improved and optimized. The following is a brief introduction to the improvement and optimization of safe operation mode design, suction tank design, pump station layout, etc

key words: optimization of operation mode of blast furnace circulating water pump station

relevant station middle station: Daquan water plant and sewage plant construction pump technical data Xinyu Iron and steel company has newly built five blast furnaces in recent years, and four blast furnace circulating water pump stations have been designed and put into operation. Corresponding to the sequence and name of blast furnace construction, the names of pump stations are eight pump stations, three pump stations, seven pump stations and six pump stations respectively. Except that the three pump stations correspond to 1#, 2# furnaces, the names of other pump stations correspond to the names of blast furnaces. The four circulating water pump stations are managed by the first power plant

among the four new blast furnace circulating water pump stations, the last six pump stations put into operation are the most perfect. This is mainly the result of our plant's gradual improvement and optimization of the design of the circulating water pump station of the blast furnace by summarizing the experience of the operation of the eighth pump station, the third pump station and the seventh pump station. The following is a brief introduction to the improvement and optimization of safe operation mode design, suction tank design, pump station layout and other aspects:

first, safe operation mode design

Third, sixth, seventh and eighth pump stations are all self circulating pump stations of blast furnace water system, and their operation modes are similar and relatively stable. 3、 There are three high-pressure pumps, medium pressure pumps and lift pumps in the sixth and eighth pump stations, and the regulator is rotated to the best position. There are five high-pressure pumps, four medium pressure pumps and three lift pumps in the seventh pump station. Each pump station has two Diesel Emergency pumps. The daily operation number of each pump station is shown in the table below

note: pressure unit mp; Flow unit m3/h

1. Power supply and operation mode

for example, in the original design of the seventh pump station, the original design is two-way power supply, one for use and one for standby, that is, one power supply with all loads of the pump station and the other for standby. In case of power loss, the safe power supply is realized through the automatic switching of the power cabinet

our factory believes that this power supply mode has some defects. The main reasons are: the power supply in use is lost, and the automatic switching circuit of the standby power supply cannot be switched on automatically, so the pump station is fully powered off; If the motor fails, the motor cabinet jumps, or the part with appreciation may no longer be subject to corporate income tax. The electrical failure may occur on the bus, causing the power in use and then closing the oil delivery valve source to trip and lose power, while the automatic switching of the standby power supply will cause the standby power supply to trip and lose power again, and the pump station will lose power comprehensively; If there is an external electrical failure of the pump station, the in-service power supply loses power, and the incoming cabinet of the power supply refuses to jump, resulting in the failure of automatic switching of the standby power supply, the pump station loses power completely. [1] Note; The middle mounted high-voltage circuit breaker in our plant has repeatedly failed to operate due to mechanical and electrical reasons] the above conditions have seriously affected the normal water supply of the blast furnace. Our factory believes that both power supplies should be put into operation and operated in sections. One is equipped with three sets of high-pressure pump sets, two sets of medium pressure pump sets, two sets of lifting pump sets, two sets of high-pressure pump sets, two sets of medium pressure pump sets, one set of lifting pump sets, and the pump room in the pump set is equipped with standby automatic switching. If the water pump in the same pump set trips in an accident, the standby pump in the pump set will start automatically. When one circuit of power supply loses power, the standby pump or diesel engine emergency pump will start automatically, and then find out the cause and decide whether to switch the power supply. In this way, the normal water supply of blast furnace is not affected by single circuit power loss, and the safety of water supply is improved

2. Operation mode of diesel engine emergency pump

in the original design of the pump station, the diesel engine emergency pump starts automatically when two power supplies lose power, providing security water for the blast furnace. Our factory believes that the starting mode of diesel emergency pump should be determined according to the number of water pumps carried by each power supply, that is, for pump stations 8, 3 and 6, the power-off automatic start of high [medium] pressure diesel emergency pump should realize power-off interlocking start with the power incoming cabinet with two high [medium] pressure motor pumps. When the power supply with two high-voltage motor pumps loses power, the water pump on the power supply with one high-voltage motor pump keeps running or starts automatically, At the same time, the high-pressure diesel pump starts automatically, and the high-pressure water supply of the blast furnace remains constant. The medium pressure pump set is similar. Similarly, other pump stations are similar. In this way, the scope of use of the diesel emergency pump is expanded. The diesel emergency pump can be automatically started when the two-way power supply loses power, or when the single-way power supply loses power, so that it can be expanded from a single emergency function to both emergency and standby functions. And the function of the diesel emergency pump must be tested frequently. The probability of single circuit power failure is high, which can make the function of the diesel emergency pump be verified by practice for many times

in recent years, our factory has experienced many single circuit power outages and one full power outage. Both the operation mode of power supply and the operation mode of diesel engine emergency pump have been well tested and proved to be safe and reliable

II. Design of suction pool

the circulating water pump station of the blast furnace has hot water pool and cold water pool. In the eighth and third pump stations, the return water pipe of the blast furnace can return to the cold and hot water pools respectively through the control of the valve on the hot water pool. In the original design of the seventh pump station, the return water enters from the lower part of the hot water pool, and the hot water is pumped by the lift pump to the cooling tower return to the cold water pool, so the hot water cannot directly enter the cold water pool. In case of large-scale power failure, the external make-up water supply is not available. Although the blast furnace has water tower and diesel engine emergency pump to supply water, if the time to restore power supply is too long, the possible situation is: the water sent by the circulating water pump station of the blast furnace from the cold water pool returns to the hot water pool from the blast furnace and continuously overflows and discharges, and there is no large amount of make-up water outside, and the water level of the cold water pool drops sharply, resulting in the final pump shutdown. And after the power supply is restored, it cannot supply water quickly, because the water pump cannot exhaust at this time. Our factory believes that connecting holes or connecting pipes should be added between the cold and hot water pools, and they are connected at a high level. In case of total power failure, the cooling water of the blast furnace regenerative pool overflows to the cold water pool through the high-level connecting pipes or holes to ensure that the water volume in the system is not lost, and the standby pump can be started at any time when the power supply is restored due to the constant water level

the high-level connection between the cold and hot water pools is also conducive to the regulation of the water level of the pool. It is adjustable through valve control, but it is too frequent. As long as the water level changes little and the mutual overflow between cold and hot water is small under normal operating conditions, it can basically achieve automatic balance. Especially in case of total power failure, the operator does not need to pay attention to the return water. This has also been tested in practice in our factory

III. equipment selection

equipment selection should be based on the requirements of high efficiency, high quality and easy maintenance. The existing situation of the equipment in our factory is

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