Guide: The US Department of Energy has funded US$81 million to support the future research and development of coal-fired power plants. Recently, the US Department of Energy (DOE) announced that it will invest US$81 million under the "Coal FIRST" program to support the design and development and system integration design of future advanced coal-fired power plants. Research to develop a flexible system suitable for future energy systems...,International Power Grid

Recently, the US Department of Energy (DOE) announced that it will invest US$81 million under the "Coal FIRST" program to support the design and development of future advanced coal-fired power plant concepts and system integration design research to develop flexible small advanced coal-fired power plants suitable for future energy systems. Power plants provide the United States with safe, stable, and reliable near-zero emissions power. The funding will include design and development, main site assessment and environmental information data, investment case analysis, and system integration design of project-scale prototypes for four types of advanced coal-fired power plant concepts.

The details are as follows:

1. Flexible supercritical coal-fired power plant

The design of such coal-fired power plants must include the following features: (1) Increase flexibility through materials, use high-nickel-based alloys in critical components, and minimize the thermal stress of these components that limit the life of the unit during rapid grade climbing, thereby Achieve power generation flexibility; (2) Modular components of the air quality control system. By using parallel modular components, individual equipment can be shut down to run at partial capacity to meet low load requirements; (3) Compact boiler layout, horizontal high temperature The convection surface is equipped with superheater and reheater header outlets on the front wall instead of the top of the boiler. Compared with the typical arrangement, the running time of high-temperature pipes is shortened by 25%-30%, and the boiler footprint is reduced. The required design and development include:

(1) Supercritical boiler island. ①Redesign the boiler concept to reduce the capacity and support flexible low-load operation, and consider the design of headers, pipes, membrane water walls, superheaters, reheaters, etc.; ②Use advanced alloy materials under 650℃ steam cycle conditions Operation; ③ The structural material needs to be considered for long-term use when the main steam temperature is close to 650℃, especially the areas with the highest temperature, such as pipes and headers; ④ Valve design under 650℃ steam conditions.

(2) Integration and control system. The integration and control system must be designed to integrate all systems and components for flexible operation.

(3) Steam turbine. The steam turbine needs to be redesigned to suit the 650°C steam cycle conditions and the concept's requirements for size, flexibility, and low load. Consideration should be given to the best turboexpander design, rotor dynamics, thermal expansion, bearings, small valves using advanced materials, blade flow design, advanced seals, and construction materials that adapt to operating temperatures.

(4) Emission control equipment. Emission control equipment should be designed for flexible operation, including operation at low loads, to meet the emission requirements of the system.

(5) Carbon capture after combustion. The post-combustion carbon capture system should be designed for flexible operation, including operation at low loads, and must be integrated with the power plant concept to meet system performance and cost requirements.
 

2. Supercritical steam cycle pressurized fluidized bed power plant

The design of such a coal-fired power plant must include the following features: (1) Pressurized fluidized bed combustion, due to the increased partial pressure of the reactants, can enhance the combustion and sulfur fixation reaction in the fluidized bed, and will be equipped with a return system, and Co-firing with natural gas to improve the climbing rate; (2) Using modular units, some modular units can be operated under partial load to improve operational flexibility and load tracking ability. The required design and development include:

(1) Pressurized fluidized bed burner system. ① Design and optimize the pressurized fluidized bed burner system to operate together with the gas/steam cycle, to achieve flexibility and low-load operation through a small modular system; ② The return material system is designed and verified for energy storage to meet the operation Claim.

(2) Steam power generation cycle. The steam turbine needs to be redesigned to suit the steam cycle conditions of 24.13 MPa and 593°C, as well as smaller size, higher flexibility and low load requirements.

(3) Integration and control system. The integration and control system must be designed to integrate all systems and components for flexible operation.

(4) Gas turbine. A new gas expansion-compressor unit needs to be designed to meet the requirements of pressurized fluidized bed burners and carbon capture.

(5) Emission control equipment. Emission control equipment should be designed for flexible operation, including operation at low loads, to meet the emission requirements of the system.

(6) Carbon capture after combustion. The post-combustion carbon capture system should be designed for flexible operation, including operation at low loads, and must be integrated with the power plant concept to meet system performance and cost requirements. In addition, a desulfurization design upstream of carbon capture is also required.

3. Gas turbine-supercritical coal-fired boiler hybrid power plant

The design of this type of coal-fired power plant must include the following features: (1) An independent coal-making and combustion system will make the preparation and storage of coal powder independent of the boiler/turbine system to avoid crawling caused by the commissioning/deactivation of the coal mill Slope limitation; (2) Incorporate into the energy storage system, store excess electricity in the energy storage system during the period when the demand is below the minimum load, which helps to initiate the initial climbing during the period when the demand increases (such as morning and evening peaks); (3 ) Using gas turbines, gas turbines will account for nearly 1/4 of the direct power output, and have the functions of quick start and climbing. The required design and development include:

(1) Supercritical boiler island. ①Integrating the gas turbine with the boiler, it is necessary to conduct modeling and simulation of combustion and flow and test to evaluate the design and flame stability, and it is necessary to re-optimize the fan, burner and burnout system to ensure complete combustion; ②Flue gas/ The air reheater is redesigned to solve the flow balance problem of flue gas and combustion-supporting air; ③ Design and optimize the heat transfer surface to operate at a higher supercritical combustion temperature, while considering material selection, system temperature, and optimal Cleaning strategy to remove surface area ash and slag, it is also necessary to evaluate the overall heat transfer characteristics of the boiler, and redesign the boiler components such as headers, water cooling walls and superheaters to achieve flexible low-load operation.

(2) Steam turbine. The steam turbine needs to be redesigned to meet the concept's requirements for smaller size, low load, and flexibility.

(3) Integration and control system. The integration and control system must be designed to integrate all systems and components for flexible operation.

(4) Emission control equipment. Emission control equipment should be designed for flexible operation, including operation at low loads, to meet the emission requirements of the system.

(5) Battery energy storage system. Based on existing battery technology, the development of new designs for integration into steam turbine/boiler systems requires research and development to reduce capital and operation and maintenance costs and improve efficiency and life.

(6) Carbon capture after combustion. The post-combustion carbon capture system should be designed for flexible operation, including operation at low loads, and must be integrated with the power plant concept to meet system performance and cost requirements.

4. Flexible coal-biomass gasification for power generation and production of carbon-free hydrogen

The system gasifies coal, biomass, and other raw materials for power generation or the production of by-products with near zero/zero carbon emissions, such as hydrogen, ammonia, or other fuels and chemicals. Such designs must include the following features: (1) Flexible coal gasifier, capable of co-firing with biomass to achieve net negative carbon emissions, and (optionally) designed to utilize other raw materials, such as petroleum-based synthetic materials ( Such as plastics) generated waste, etc.; (2) Syngas treatment and carbon capture systems, such systems must be compatible with the components of coal gasifier syngas. The required design and development include:

(1) Flexible coal gasifier. The coal gasifier will be designed for co-firing with biomass, which needs to ensure overall negative carbon emissions and may also require the introduction of other raw materials.

(2) Syngas treatment and carbon capture system. In the system design, it is necessary to evaluate the impact of biomass and/or other raw materials on the environment and processes caused by the synthesis gas composition.

(3) Integration and control system. The integration and control system must be designed to integrate all systems and components for flexible operation.