Coal Thermal Power as a Base-load Power Source Aiming for Significant Efficiency Improvements
As part of an effort ultimately aimed at utilizing coal more efficiently while reducing the burden on the environment, Osaki CoolGen Corporation, based in Osaki Kamijima-cho, Hiroshima on one of the islands in the beautiful Seto Inland Sea area, has been working on NEDO’s “Integrated Coal Gasification Fuel Cell Combined Cycle Demonstration Project” to significantly improve coal-based thermal power. Under the motto of “use whatever technologies are available to improve thermal efficiency”, they are about to demonstrate combined cycle as well as triple combined cycle systems based on the use of coal gasification technology instead of combusting coal in its normal form.
Applying the Accomplishments from Experiments at the Pilot Plant to Larger Scale Demonstration Power Plants
In the past, NEDO conducted the “Multi-purpose Coal Gasification Technology Development-Coal Energy Application for Gas, Liquid & Electricity (EAGLE)” program through FY 2014 to improve the efficiency of coal-based thermal power. There, NEDO did demonstration tests with “oxygen injection” instead of air to increase the heat generation of coal gas when gasifying coals in the gasification furnace.
Why do we gasify coal instead of burning it as is? Because converting coal to flammable gas enables the application of combined cycle technology as used in LNG-fired thermal power to increase overall efficiency. In addition, we can recover CO2 before burning which enables efficient CO2 separation and capture. Moreover, even low-grade varieties of coal such as brown coal which are difficult to use as they are can be utilized in gasification. These low-grade varieties of coal cost less and account for half of all the recoverable coal reserves in the world, but they are not fully utilized.
The project NEDO is conducting with Osaki CoolGen is designed to apply the accomplishments from the EAGLE pilot plant to a demonstration test at the gasification furnace which is eight times the size and close to actual scale, so the results will easily be transferred to practical application. “This project is considered one of the highest priority projects in the NEDO Environment Department and I can sense the high expectations,” emphasizes Mr. Seiichi Yamamoto, Program Manager and Chief Officer of the NEDO Environment Department.
Three-Phase Project Oxygen Injection IGCC, CO2 Separation and Capture, and Fuel Cell
The project is going to have three phases before reaching the final year of the project in FY 2021. The first phase is the demonstration of the Oxygen Injection Integrated Coal Gasification Combined Cycle (IGCC) technology. In this phase we gasify coal particles in gasification furnaces to move gas turbines and use the heat produced to move steam turbines as well to achieve combined power generation.
Installation and configuration of all the equipment for the demonstration power plant has been completed and full-scale test runs started in August. “We have completed combining all the equipment and started test runs of IGCC. We’ll verify the reliability through a 5,000-hour long-term endurance test. Safety is the most important thing for this kind of facilities. Ensuring safety and environmental conservation are our highest priorities and we’ll try to accomplish our goals of technology development,” says Mr. Kenji Aiso, President and Representative Director of OSAKI CoolGen Corporation. While traditional coal- fired thermal power creates a large amount of ash as a byproduct, with coal gasification those impurities will be exhausted as a reduced volume of glassy slag. In the EAGLE project, we verified that this molten slag made of coal cinders can be stably removed.
The second phase of the demonstration involves the CO2 separation and capture technology. We separate a part of gas produced from the coal and recover 90% of the CO2 content, with the goal of reaching a purity of 99% or above, and then assess the reliability and economic efficiency of integrating CO2 separation and capture with IGCC. Then the third phase is the demonstration of the Integrated Coal Gasification Fuel Cell Combined Cycle (IGFC) technology, which will use the hydrogen (H2) content of the coal gas to generate power through fuel cells in addition to the gas turbines and steam turbines in the IGCC. “We would like to develop the IGFC system technology once we establish each component technology,” Mr. Aiso says. “The goal of the ‘Technology Roadmap for Next-Generation Thermal Power Generation’ is to reduce CO2 by 30% by 2030 through IGFC implementation. To accomplish it the government and private sector have come together for the further improvement of the efficiency of next-generation thermal power systems,” Chief Officer Yamamoto of NEDO says.
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The 10 largest coal producers and exporters in Indonesia:
The 10 largest coal producers and exporters in Indonesia:
