CN-121975983-A - Energy-saving control method and system for blast furnace soft water closed circulation system

CN121975983ACN 121975983 ACN121975983 ACN 121975983ACN-121975983-A

Abstract

The invention relates to the field of industrial circulating water energy optimal control, and discloses an energy-saving control method of a blast furnace soft water closed circulating system, which comprises the steps of selecting a cooling branch with minimum branch flow satisfaction degree from a plurality of cooling branches as a reference branch when a main pipeline valve is opened and a main pump runs at an initial rotating speed; and determining a target flow value of the non-reference branch according to the designed flow proportion relation, and eliminating hydraulic imbalance by adjusting the opening of the branch valve to finish hydraulic balance regulation. And then fixing a branch valve, taking the total water supply flow as a target, adjusting the rotating speed of the main pump for a plurality of times until the rotating speed reaches a preset required flow value, and determining the minimum operating rotating speed to eliminate energy waste caused by unmatched working conditions. And finally, calculating the operation efficiency of the main pump, and if the operation efficiency is lower than the efficiency threshold value, synchronously adjusting the rotation speed of the water pump and the opening degree of the main pipeline valve within the allowable range of the total flow deviation until the operation efficiency meets the requirement. Therefore, the whole energy efficiency maximization of the system under the premise of ensuring safe cooling is realized.

Inventors

XIAO QILIN
ZHANG KAIJUN
ZHOU LI
XIN BO
ZHU JINFENG
LIU XUAN

Assignees

中钢设备有限公司

Dates

Publication Date: 20260505
Application Date: 20260202

Claims (7)

1. An energy-saving control method of a blast furnace soft water closed circulation system is characterized by comprising the following steps: receiving real-time flow of a plurality of cooling branches under the condition that a main pipeline valve is opened and a main circulating water pump runs at an initial rotating speed in a blast furnace soft water closed circulating system, and obtaining a design flow corresponding to each cooling branch in the plurality of cooling branches; determining a target flow value corresponding to each non-reference branch in the plurality of non-reference branches according to a preset proportional relation between the design flow of each cooling branch in the plurality of cooling branches and the design flow of the reference branch; After hydraulic balance regulation and control among a plurality of cooling branches is completed, fixing the valve opening of each cooling branch, receiving the total water supply flow of the system, and adjusting the operation rotating speed of the main circulating water pump for a plurality of times by taking the total water supply flow of the system as a control target until the total water supply flow of the system is adjusted to a preset required flow value so as to determine the minimum operation rotating speed of the main circulating water pump; And when the operation efficiency is smaller than a preset efficiency threshold value, synchronously adjusting the operation speed of the main circulating water pump and the opening of a main pipeline valve under the condition that the deviation of the total water supply flow of the system relative to a preset required flow value does not exceed a second preset allowable range until the operation efficiency is larger than or equal to the preset efficiency threshold value.
2. The method for controlling energy saving of a closed circulation system of soft water of blast furnace according to claim 1, wherein the determining a target flow value corresponding to each of the plurality of non-reference branches comprises: Calculating the ratio of the design flow of each non-reference branch to the design flow of the reference branch, and determining the ratio as the target flow ratio corresponding to each non-reference branch; and determining a target flow value corresponding to each non-reference branch according to the real-time flow of the reference branch and the target flow ratio.
3. The energy saving control method of a closed circulation system of soft water of blast furnace according to claim 1, wherein the calculating of the operation efficiency of the main circulation water pump comprises: And determining the operation efficiency of the main circulating water pump according to the real-time operation power, the real-time lift and the total water supply flow of the system.
4. The method for energy-saving control of a closed circulation system of soft water of blast furnace according to claim 1, wherein the preset efficiency threshold is determined by one of: determining a corresponding energy efficiency limiting value according to the energy efficiency standard corresponding to the main circulating water pump; Determining a corresponding lower limit value of the efficient working area according to a rated performance curve in a performance specification file corresponding to the main circulating water pump; Generating a corresponding efficiency reference value according to actual measurement operation data of the main circulating water pump under different operation frequencies; and determining the energy efficiency limit value, the high-efficiency working area lower limit value or the efficiency reference value as a preset efficiency threshold value.
5. An energy-saving control system of a blast furnace soft water closed circulation system, which is characterized by comprising: The detection unit is used for collecting the total water supply flow of the system, the real-time flow of the plurality of cooling branches, the real-time running power of the main circulating water pump motor, the pressure at the inlet and the pressure at the outlet of the main circulating water pump and sending the total water supply flow and the real-time flow to the control unit; The control unit is used for receiving the total water supply flow of the system, the real-time flow of a plurality of cooling branches and the real-time running power of the main circulating water pump motor, and sending a control instruction to the execution unit by executing the energy-saving control method of the blast furnace soft water closed circulating system according to any one of claims 1 to 4; And the execution unit is used for receiving the control instruction so as to adjust the running rotating speed of the main circulating water pump, the valve opening of each cooling branch and the opening of the main pipeline valve.
6. The energy-saving control system of the blast furnace soft water closed circulation system according to claim 5, wherein the detection unit comprises a main pipeline flow sensor arranged at an outlet position or a backwater main pipeline position of the main circulating water pump, a plurality of branch pipeline flow sensors respectively arranged on a plurality of key cooling branches, an electric quantity monitoring module connected with a motor of the main circulating water pump, and a pressure sensor arranged at an inlet position and a pressure sensor arranged at an outlet position of the main circulating water pump.
7. The energy-saving control system of the closed circulation system of soft water of blast furnace according to claim 5, wherein the executing unit comprises a frequency converter connected with a main circulation water pump motor, branch regulating valves respectively arranged on a plurality of cooling branches, and main pipeline regulating valves arranged on a main pipeline.

Description

Energy-saving control method and system for blast furnace soft water closed circulation system Technical Field The invention relates to the field of industrial circulating water energy optimal control, in particular to an energy-saving control method and system of a blast furnace soft water closed circulating system. Background In the blast furnace smelting process, a soft water closed circulation cooling system is critical to the longevity and safety of the blast furnace. In the existing blast furnace soft water closed circulation cooling system, the following technical problems often exist: Firstly, the design of the blast furnace soft water closed circulation system strictly conforms to the specification requirements of industrial circulating cooling water system design specifications (GB 50050-2007) 3.1.3 and the like, and 10-15% of flow capacity surplus and 15-20% of lift surplus are reserved during selection. The design principle is necessary and reasonable in the system design level, and is initially aimed at coping with maximum load, equipment safety margin and unpredictable working condition fluctuation, so that the cooling safety and reliability of the blast furnace are fully ensured. However, the actual running resistance of the system is much lower than the design value. In the face of this normalized operating state, the traditional "constant frequency water pump + valve throttling" control mode exposes fundamental drawbacks. To match the reduced system requirements, this mode is forced to artificially increase the resistance by closing the main pipe valve to "consume" the excess head of the pump due to the design margin. The valve is used as a main regulating means, so that a large amount of energy is wasted in the throttle loss of the valve in an ineffective way, so that a reasonable margin which is set for ensuring safety in a design stage is evolved into continuous unreasonable energy consumption waste in an operation stage; Secondly, the rated capacity (particularly the lift) of the water pump based on standard margin selection is generally larger than the actual requirements of the system under most working conditions. The valve is directly driven in operation, and the pump is matched with a passive control mode, namely the valve is closed, the system resistance is artificially increased to match the output of the water pump, so that the working point of the system is forced to be moved to the inherent characteristic of the water pump. As a result, a significant amount of energy, which would otherwise be used to overcome the inherent resistance of the pipe network, is inefficiently consumed in valve throttling losses, creating an inherent disadvantage of poor system operating economics; Third, each cooling branch is at risk of hydraulic imbalance due to inherent resistance differences. In the conventional mode, any attempt to improve local flow by adjusting a single bypass valve will immediately interfere with the operating point of the entire network due to the strong coupling of the system, resulting in uncontrolled fluctuations in the flow of the other bypass. The operators are in the dilemma of pulling and sending the whole body, and cannot perform fine branch balance regulation and control, so that the cooling uniformity is sacrificed, and potential safety hazards are buried; Fourth, the existing technical improvement scheme (such as simple frequency conversion transformation or simple branch balance) is mostly the fragmentation optimization of "headache doctor head and foot pain doctor foot". They either focus on overall energy conservation but exacerbate branch non-uniformity, or solve only local balancing but fail to achieve global energy efficiency optimization. The prior art lacks a systematic closed-loop method capable of carrying out cooperative optimization on three strong coupling targets of 'branch equalization', 'lift surplus elimination' and 'efficient operation of a water pump', so that a blast furnace soft water system is loitered in the dilemma of 'low energy efficiency when safety is ensured and poor uniformity when energy conservation is required' for a long time. Disclosure of Invention This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The invention provides an energy-saving control method and system for a blast furnace soft water closed circulation system, which are used for solving one or more of the technical problems mentioned in the background art section. The invention provides an energy-saving control method of a blast furnace soft water closed circulation system, which comprises the steps of receiving real-time flow of a plurality of cooling branches and obtaining design flow corre