Cogeneration Control System Prevents Heat Exchanger Corrosion
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Solution Overview
Problem
Cogeneration systems face corrosion issues due to condensate water accumulation in heat exchangers, which occurs when exhaust gas moisture condenses and reacts with components, leading to potential system failure and increased maintenance costs.
Innovation Solution
A control system equipped with an exhaust gas temperature sensor, a temperature comparator, and an operation stopper that detects and compares exhaust gas temperatures with predetermined values, stopping the system when temperatures drop below a certain threshold to prevent condensate water accumulation and subsequent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the heat exchanger warms up coolant using exhaust heat, then thermal efficiency is improved, but condensate water accumulates causing corrosion
Solution Approach 1:
The control system performs preliminary detection of exhaust gas temperature and compares it with a predetermined threshold value before allowing the heat exchanger to operate. When the temperature is below the threshold, the system prevents operation in advance, thereby avoiding condensate water accumulation and corrosion before they can occur.
Solution Approach 2:
The system continuously monitors exhaust gas temperature through a temperature sensor and provides feedback to the control unit. The control unit adjusts the operation of the heat exchanger based on this feedback, maintaining exhaust gas temperature above the condensation point to prevent corrosion while maximizing thermal efficiency.
2Productivity
If the system operates continuously, then productivity is improved, but system reliability deteriorates due to corrosion
Solution Approach 1:
The control system detects exhaust gas temperature in advance and prevents operation when temperature is too low, avoiding corrosion events before they occur. This allows continuous operation under safe conditions while preventing reliability degradation.
Solution Approach 2:
The system changes the operational parameter (operation status) based on the exhaust gas temperature parameter. When temperature drops below the predetermined threshold, the system transitions from operating state to stopped state, preventing corrosion while maintaining productivity during suitable operating conditions.
3Use of energy by moving object
If the heat exchanger operates at low exhaust gas temperature, then energy utilization is improved, but condensate water condensation occurs
Solution Approach 1:
The temperature sensor provides continuous feedback on exhaust gas temperature to the control unit. The control unit adjusts heat exchanger operation based on this feedback, ensuring temperature remains above the condensation point and preventing moisture condensation while maximizing energy utilization.
Solution Approach 2:
The system changes the operational state of the heat exchanger based on exhaust gas temperature parameters. When temperature falls below the predetermined threshold, operation is stopped to prevent condensation, thereby losing some energy utilization opportunity but avoiding moisture accumulation and corrosion.
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
Prevents condensate water accumulation in the heat exchanger, thereby reducing corrosion risks and improving system durability and lowering maintenance costs by ensuring the coolant temperature remains above the condensation point.
Implementation Method 1
an exhaust gas temperature sensor that detects temperature of exhaust gas passing the heat exchanger
Implementation Method 2
a heat exchanger that exchanges heat with coolant of the engine with exhaust heat from the engine to warm up the coolant
Implementation Method 3
a temperature comparator that compares the detected exhaust gas temperature with a predetermined value
Data Source
AI summary
In an apparatus (and a method) for controlling a cogeneration system equipped with a generation unit having a generator connectable to an AC power feed line between a commercial power network and an electrical load and an internal combustion engine for driving the generator, and a heat exchanger that exchanges heat with coolant of the engine with exhaust heat from the engine to warm up the coolant, there are provided with an exhaust gas temperature sensor that detects temperature of exhaust gas passing the heat exchanger, a temperature comparator that compares the exhaust gas temperature with a predetermined value and an operation stopper that stops the operation of the cogeneration system when the exhaust gas temperature is found to be less than the predetermined value. With this, it becomes possible to prevent moisture in the exhaust gas from being condensed and accumulated in the exhaust-gas heat exchanger.