Blast Furnace Gas CCPP Power Generation Technology Development Space

Strengthening cooperation on energy efficiency and carbon reduction

Takahiro Kawaguchi, Chairman of Mitsubishi Power Gas Turbine Engineering Technology (Nanjing) Co., Ltd, said in his speech, "In the first half of this year, due to the contraction of demand, supply shocks, and the outbreak of New Crown Pneumonia, the profits of the iron and steel industry have shrunk considerably, and the prices of the products have continued to be low. Around the world, the rapid development of zero-carbonization, hydrogen energy utilization, and digital technology has led to dramatic changes in the market environment as well as in customer needs. In the face of complex market conditions, Mitsubishi is willing to work hand in hand with Chinese steel companies to strengthen cooperation on energy saving and carbon reduction."

Xu Xiufu, General Manager of Mitsubishi Power Gas Turbine Engineering Technology (Nanjing) Co., Ltd, said, "With the opening of the national carbon emissions circle trading market, the carbon reduction of CCPP generating sets (gas-steam combined cycle generating sets) will become a new profit point for the steel industry in addition to self-generated electricity and at the same time win more social and environmental benefits for the enterprise. On the basis of not changing the existing production process and energy supply structure, CCPP technology is one of the effective measures for energy saving and carbon reduction in the steel industry. Domestic Mitsubishi CCPP generating units have so far generated more than 200 billion kWh of electricity, saving more than 58 million tons of standard coal for the iron and steel industry, and reducing carbon dioxide emissions by more than 150 million tons. Compared with high-temperature, high-pressure and ultra-high-pressure boiler-generator sets constructed during the same period, the CCPP generator sets are more than 30% ahead in all indicators."

To date, 33 Mitsubishi CCPP generator sets of various models have been applied in domestic steel enterprises, of which 30 have been put into operation and 3 are under construction. The cumulative operating time of the commissioned units has exceeded 2.37 million hours, with an availability rate of more than 99%, eliminating the steel industry's initial concerns about the operational reliability of CCPP generator sets.

Improvement of low-carbon technologies

Low-carbon development is an important content to solve the bottleneck of environmental, energy and resource constraints and to promote the high-quality development of the industry, as well as the key embodiment and ultimate goal.

Gao Xue, Deputy Chief Engineer of Metallurgical Industry Planning and Research Institute, said: "Key large and medium-sized iron and steel enterprises represent the advanced level of industry development. According to the data published by China Iron and Steel Industry Association, the comprehensive energy consumption of tons of steel of key large and medium-sized iron and steel enterprises nationwide in 2021 will be 549.24 kg standard coal, a decrease of 0.59 kg standard coal compared with 2020, a decrease of 0.11%. Compared with 2015, the percentage of decrease in comprehensive energy consumption per ton of steel reached 4%."

Gaoxue introduced that compared with 2020, the coke oven gas release rate in 2021 decreased by 0.39 percentage points or 40.17%; the blast furnace gas release rate decreased by 0.08 percentage points or 6.30%; and the ton of steel recovered from converter gas reached 119.2 cubic meters, an increase of 1.40%. The rate of waste heat and energy self-generation, which represents the level of secondary energy utilization in the industry, gradually increased by 10 percentage points from 44% in 2015 to 54% in 2021.

According to incomplete statistics, in 2020, 55 CCPP generator sets with a total installed capacity of 6,156 MW were built in key statistical steel enterprises in China.In 2020, 357 steam generator sets with a total installed capacity of 2,386 MW had been built in key statistical steel enterprises in China.In 2020, nearly 700 gas boiler generator sets with a total installed capacity of 34,730 MW, a year-on-year increase of 3,130 MW. According to statistics, the national average self-generation rate in 2021 will be around 54%.

In order to improve the application level of low-carbon transformation technologies, Gao Xue put forward three suggestions: First, vigorously promote the level of automated coal distribution in coke ovens, advanced process technologies such as coal saving and coke reduction in blast furnaces, improve the efficiency of coal utilization, and promote the efficient transformation of energy. The second is to increase the proportion of electric energy in the end energy consumption of the iron and steel industry, systematically improve the efficiency of energy utilization, and advocate and promote the CCPP high-efficiency power generation technology. Third, vigorously develop energy storage technology, relying on iron and steel enterprises' gas power generation and waste heat generating units, based on solid heat storage and molten salt heat storage technology, relying on the energy digitization platform, and utilizing multi-energy synergistic control technology combined with time-sharing tariffs, power trading, etc., to enhance the adjustable capacity of the iron and steel enterprises' energy system, so that the iron and steel enterprises can undertake the important functions of shaving peaks and filling in valleys, responding to the demand side, and promoting the consumption of new energy sources, and to solve the problems caused by the access of large-scale renewable energy sources. It also solves the problems of regional source-load mismatch caused by large-scale renewable energy access, enhances the interactive capability of source-network-load, balances regional energy use, and enhances the value of energy.

Improvement of self-generation efficiency

During the "14th Five-Year Plan" period, under the dual control of carbon reduction and energy consumption, the production capacity of the iron and steel industry will be strictly controlled, further forcing enterprises to improve efficiency, reduce carbon, reduce costs and increase efficiency.

Yong Yizheng, Director Engineer of Mitsubishi Power Gas Turbine Engineering Technology (Nanjing) Co., Ltd, said, "Under the background of energy saving and carbon reduction, the iron and steel industry has rapidly increased the proportion of self-generated electricity from gas, and in the absence of a significant increase in production capacity, compared with the total installed self-generated electricity, the end of the 'Thirteenth Five-Year Plan' rose by 12.8 percent . Although the overall self-generation level of iron and steel enterprises has been improving, the intermediate parameter generators represented by double-super and subcritical account for the majority of the industry, and the proportion of large-scale high-efficiency CCPP generator sets with a power generation efficiency of more than 45% is still relatively small. Large CCPP generator sets installed capacity of 2983 MW, the same period with Japan's steel industry large CCPP generator sets installed capacity of 2363 MW, through China's 1 billion tons of iron and steel production capacity and Japan's 90 million tons of iron and steel production capacity comparative analysis of China's iron and steel industry advanced high-efficiency blast furnace gas power generation technology has a lot of room for development."

Jiang Zuoming, Director Engineer of Operation Operation Area of Anshan Energy Control No.2 Power Plant, said, "Anshan Iron & Steel attaches great importance to environmental protection and the development of recycling economy, and always adheres to the concept of 'recycling development'. In order to efficiently utilize the affluent gas, it adopts the CCPP power generation process for the efficient utilization of the affluent coal gas. Compared with the conventional gas generator set, 180 MW CCPP generator set has strong adaptability and wide range of blast furnace gas calorific value; the combustion engine and steam engine are arranged in double shafts, which has the capability of heating to the public and reduces the air pollution of the urban area from the coal-fired heating boiler; through in-depth tapping of potentials and optimization of operation, the power generation efficiency reaches more than 47.3%, which is higher than that of the conventional gas boiler unit;"

Zhang Jianqiu, combustion engine engineer of the power generation division of Maanshan Steel's Energy and Environment Department, said, "The company's Energy and Environment Department adopts the first domestic low calorific value single-shaft M701SDAX CCPP generator set, the unit is designed to have a rated load of 183 megawatts, with a design thermal efficiency of more than 47% and a measured efficiency of more than 48%, and an annual power generation capacity of about 1,427.4 million kilowatt-hours. It can fully recycle and utilize the affluent gas resources generated from iron and steelmaking, reduce gas dispersion, protect the ecological environment and improve the self-generation efficiency."

"Since the commissioning of the 183 MW CCPP generating unit of Masteel Beihu Power Plant, it has realized continuous safe and stable long-cycle production, and has generated a total of 780.3 million kWh of electricity from January to June 2022, with a load factor of 99%, realizing a win-win situation in terms of economic, social and environmental benefits." Zhang Jianqiu said.

In order to further improve quality and efficiency and reduce the intensity of carbon emissions, Mitsubishi Power is currently carrying out research and development work on more efficient and miniaturized CCPP generator sets for steel companies. At the same time, Mitsubishi Power is also developing hydrogen- and ammonia-fired gas turbines, a technology that will use entirely zero-carbon fuels and realize zero carbon emissions.