CHP System Heat Exchanger Design for Organic Waste
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Solution Overview
Problem
Existing combined heat and power (CHP) systems face challenges in efficiently utilizing waste organic resources, particularly in small-scale applications, due to high costs, energy losses, and complexity, especially when dealing with mixed organic residues and varying fuel heat values, which affect temperature control and overall efficiency.
Innovation Solution
A CHP system configuration that uses a single high-temperature heat exchanger to directly heat compressor air to the maximum turbine inlet temperature, eliminating the need for a combustion air preheater and recuperator, and incorporates a cyclone particle separation system and proportional gas flow control to maintain consistent combustion gas temperatures, ensuring efficient energy recovery and reduced system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single high-temperature heat exchanger is used to directly heat compressor air, then thermal-electric efficiency is improved and system complexity is reduced, but temperature control difficulty increases
Solution Approach 1:
The patent combines the functions of the combustion air preheater and the hot heat exchanger into a single high-temperature heat exchanger. This merger eliminates the need for separate preheating equipment and recuperators, reducing the number of components while maintaining efficient heat transfer from combustion gases to compressor air, thereby improving thermal-electric efficiency without proportionally increasing system complexity
Solution Approach 2:
The single high-temperature heat exchanger performs multiple functions: it preheats combustion air, transfers heat from combustion gases, and operates at maximum turbine inlet temperatures. This multi-functional design replaces multiple specialized components, simplifying the overall system architecture while preserving efficiency
2Duration of action of stationary object
If combustion gas temperature is tightly controlled, then heat exchanger component life is extended and manufacturing cost is reduced, but system control complexity increases
Solution Approach 1:
The patent maintains combustion gas temperature within a controlled range (950-1100°C) to match the maximum operating temperature of metal heat exchangers. By adjusting and stabilizing this critical temperature parameter, the system enables the use of durable metal components instead of ceramics, extending component life and reducing manufacturing costs while managing control complexity through targeted temperature regulation
3Device complexity
If a single heat exchanger is used instead of multiple heat exchangers, then device complexity is reduced and cost is reduced, but temperature control precision may worsen
Solution Approach 1:
The single heat exchanger is designed with differentiated zones or sections that handle different temperature profiles and heat transfer requirements. This local quality approach allows different portions of the heat exchanger to optimize for specific functions, maintaining temperature control precision across the entire system despite the reduced component count
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 configuration enhances thermal-electric efficiency, reduces costs, and extends the life of heat exchanger components by tightly controlling combustion gas temperatures, allowing for the use of metal heat exchangers instead of more expensive ceramics, and achieving higher heat energy recovery and power output.
Implementation Method 1
a heat exchanger to heat the compressor air from the compressor outlet temperature to a maximum temperature needed at the inlet of the turbine
Implementation Method 2
a cyclone particle separation system
Implementation Method 3
proportional gas flow control to maintain consistent combustion gas temperatures
Implementation Method 4
an open Brayton cycle gas turbine in which ambient air is compressed in the compressor of the turbine and then directed to a heat exchanger to be heated by the organic combustion system. The highly heated air is then expanded in the turbine to produce work to turn a generator and generate electricity
Data Source
Figure 1
Figure 2
AI summary
A combined heat and power (CHP) system. The CHP system including a combustion chamber with an air inlet and an exhaust. The combustion chamber configured to receive a hot secondary gas for combustion. A heat exchanger coupled to the particle separator receives mixed combustion gases and transfers heat to a secondary gas. The CHP system also includes a turbine configured to receive and compress a secondary gas and direct the compressed secondary gas to the heat exchanger, the turbine is also configured to receive a heated compressed secondary gas and expand it to generate work therefrom, the expanded heated secondary gas is also used for combustion and to regulate the temperature of the combustion gases entering the heat exchanger. A generator is connected to the drive shaft of the turbine and configured to generate electricity with the work generated therein.