Deaerator Circulation Pump Control for Steam Plant Water Hammer Prevention
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Solution Overview
Problem
In steam power plants, during condensate throttling operations, the rapid closure of the deaerator water level control valve can lead to voids in the condensate line, causing water hammer when returning to normal operation, due to the slower closure time of motor-operated valves compared to air-operated valves.
Innovation Solution
The deaerator circulation pump is temporarily driven during condensate throttling to ensure the condensate line is filled with water, preventing voids and subsequent water hammer by returning condensate water to the upstream side, and the controller manages the valve operations to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the deaerator water level control valve is closed rapidly during condensate throttling, then the response speed is improved, but voids are generated in the condensate line causing water hammer
Solution Approach 1:
The deaerator circulation pump is activated before or during the valve closure process to preliminarily fill the condensate line with water, preventing void formation that would cause water hammer when the valve closes rapidly
Solution Approach 2:
The deaerator circulation pump acts as an intermediary device that introduces water into the condensate line to replace voids, mediating between the rapid valve closure and the prevention of water hammer
2Device complexity
If motor-operated valves are used for supply line shutoff, then the device complexity is reduced, but the closure time is slower compared to air-operated valves
Solution Approach 1:
The control functions of multiple valves (deaerator water level control valve, first supply line shutoff valve, second supply line shutoff valve) are merged into a single automated control system that coordinates their operation to achieve both simplicity and speed
Solution Approach 2:
The controller activates the deaerator circulation pump in advance or concurrently with valve closure operations to ensure the condensate line remains filled with water, compensating for the slower closure speed of motor-operated valves
3Object-affected harmful factors
If the deaerator circulation pump is temporarily driven during condensate throttling, then water hammer is prevented, but energy consumption increases
Solution Approach 1:
The deaerator circulation pump operates periodically or temporarily only during condensate throttling events rather than continuously, reducing overall energy consumption while providing protection when needed
Solution Approach 2:
The operating parameters of the deaerator circulation pump (flow rate, operating duration) are dynamically adjusted based on the specific throttling conditions to minimize energy consumption while effectively preventing water hammer
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents water hammer during the transition from condensate throttling to normal operation without altering the plant configuration, ensuring safe and efficient operation.
Implementation Method 1
a deaerator circulation pump that returns condensate water flowing out from the deaerator to a part of the condensate line between the heater and the deaerator
Implementation Method 2
a heater that heats the condensate water generated in the condenser, by extraction steam of a steam turbine
Implementation Method 3
a deaerator that heats and deaerates condensate water generated in a condenser, by extraction steam of a steam turbine, and temporarily stores the heated and deaerated condensate water
Implementation Method 4
The steam having driven the steam turbine is condensed in a condenser to become condensate water
Data Source
AI summary
A condensate and feedwater system includes: a deaerator circulation pump that returns condensate water flowing out from a deaerator to a part of a condensate line between a heater and the deaerator; an apparatus to be supplied with part of the condensate water flowing from the heater toward the deaerator, through a supply line branched from the condensate line; a supply line shutoff valve that switches between communication and interruption of the supply line; and a controller that controls opening/closing of the supply line shutoff valve and driving/stopping of the deaerator circulation pump. The controller closes the supply line shutoff valve from an open state at normal operation and at least temporarily drives the deaerator circulation pump from a stopped state at normal operation, in condenser throttling in which supply of extraction steam of a steam turbine to the heater and the deaerator is reduced as compared to that at normal operation and a deaerator water level control valve is closed.