Control method for optimizing generated power of solar-aided coal-fired power system under off-design working conditions
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Solution Overview
Problem
Existing solar-aided coal-fired power systems face challenges in efficiently and flexibly operating under off-design conditions, particularly due to solar irradiance fluctuations and changing power load requirements, leading to suboptimal power generation and complex operation.
Innovation Solution
A control method that adjusts the solar-coal feedwater flow distribution ratio within the solar-coal complementary loop to maximize steam turbine output power, while keeping the main steam flow rate and temperatures unchanged, using specific enthalpy calculations and corresponding relationships to optimize power generation under varying solar irradiance and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional control methods are used for solar-aided coal-fired power systems, then the system can operate under design conditions, but the system cannot efficiently and flexibly operate under off-design conditions with solar irradiance fluctuations and changing power load requirements
Solution Approach 1:
The patent applies dynamics by making the solar-coal feedwater flow distribution ratio adjustable and variable according to real-time operating conditions. The control method dynamically determines the optimal distribution ratio based on current solar irradiance, power load requirements, and system state, allowing the system to adapt flexibly to off-design conditions while maintaining efficient power generation. This transforms the previously fixed control approach into a dynamic, responsive control system.
Solution Approach 2:
The patent changes the key parameter of feedwater flow distribution ratio to optimize system performance under varying conditions. By adjusting this parameter based on off-design operating conditions, the system can maximize power generation efficiency while accommodating solar irradiance fluctuations and changing load requirements. The method establishes a relationship between the distribution ratio and system performance to guide parameter optimization.
2Productivity
If the main steam flow rate is changed to adjust power output, then power load requirements can be met, but the economic and flexible operation of the system is reduced
Solution Approach 1:
The patent applies local quality by making a localized adjustment to the feedwater flow distribution ratio in the solar-coal complementary loop rather than changing the overall main steam flow rate. This localized control approach allows the system to meet power load requirements while maintaining optimal operating conditions for the steam turbine and preserving economic operation. The adjustment is confined to a specific part of the system where it has maximum effect with minimum disruption.
3Loss of energy
If solar energy is used to compensate for coal-fired power generation instability, then the cost of stand-along concentrated solar power generation can be saved, but the system becomes difficult to control under varying solar irradiance conditions
Solution Approach 1:
The patent applies feedback by continuously monitoring the system state and solar irradiance conditions, then using this information to adjust the feedwater flow distribution ratio in real-time. The control method incorporates feedback loops that sense changes in operating conditions and automatically modify the distribution ratio to maintain optimal performance. This feedback mechanism simplifies control by making the system self-regulating rather than requiring complex external control systems.
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 method effectively maximizes power generation and improves the economic and flexible operation of solar-aided coal-fired power systems by optimizing the water flow rate in the solar heat collection system, enhancing the use of solar energy without altering the main steam flow rate or temperature.
Implementation Method 1
a specific enthalpy of water heated by the solar heat collection system
Implementation Method 2
water heated by the solar heat collection system
Implementation Method 3
a specific enthalpy of water heated by the solar heat collection system and heated by a high-pressure heater after being mixed
Implementation Method 4
heated by a high-pressure heater
Implementation Method 5
calculate the generated power... maximizing an output power of the steam turbine
Data Source
AI summary
A control method for optimizing generated power of a solar-aided coal-fired power system under off-design working conditions sets maximizing generated power without changing main steam flow rate as a control goal. A solar-coal feedwater flow distribution ratio is adjusted to adjust water flow rate heated by a solar heat collection system, so as to achieve the control goal. Control steps include reading relevant information; calculating the water flow rate range heated by the solar heat collection system, and an applicable solar-coal feedwater flow distribution ratio range; establishing a correspondence between the generated power and the solar-coal feedwater flow distribution ratio within this range; selecting a solar-coal feedwater flow distribution ratio corresponding to the maximum generated power; and adjusting the water flow rate entering the solar heat collection system to an optimized value. The present invention can flexibly control the solar-coal coupling and improve the economy.