Recently, Shougang Jingtang Company has successfully completed the full load test of combined cycle power plant (CCPP) and the 35,000 tons per day of low-temperature multi-effect desalination project was set for official production and operation. This marks the completion of the world’s first “five-in-one” green recycling system with gas, heat, electricity, water, and salt, setting new record for green utilization of low-quality energy.

The CCPP unit is an important part of the development cycle of Jingtang Company. The unit consists of gas turbine and supporting generator, waste heat boiler, and steam turbine and supporting generator. As the gas combusts in the gas turbine with air, it will expand and push the gas turbine generator to generate electricity. The discharged high-temperature gas is channeled to the waste heat boiler to generate high-temperature and high-pressure steam to power the steam turbine up for electricity generation. At the same time, the low-quality exhaust steam after power generation is used as the heat source of the seawater desalination device to prepare the desalinated water, and the generated strong brine is used as the salt alkaline chemical raw material to extract high value-added chemical products. The whole process constitutes a green recycling material flow of “gas, steam, electricity, desalinated water and salt alkaline products.” The split shaft arrangement of Jingtang Company’s CCPP unit enables the physical separation of gas power and steam power generation systems. It boasts of its advantages of wide operating conditions, high power generation efficiency, and adjustable fuel requirement. The unit’s overall combined power generation efficiency is as high as 47%, which is 2% higher than that of the same model and ranks first in the industry. Under the condition of the full blast furnace gas, the power generation capacity remains above 150 MW with 45% power generation efficiency, and the annual profit of 145 million yuan.

The newly-built phase II seawater desalination is the core of the “five-in-one” green recycling system, which adopts the technical route of “generating water and electricity simultaneously and coupling thermal and film desalination processes” and the 35,000 tons per day of low-temperature multi-effect seawater desalination device. It is the largest single unit in China and is designed, manufactured, installed, and operated independently by Shougang Group. The desalination of seawater uses the exhaust steam of steam turbine as the heat source. Compared to the conventional power plants’ extraction mode, the overall thermal efficiency is increased from 30% to 81.5%, and the energy consumption cost of water desalination is reduced by 50%. The desalinated water produced is then added into the circulating water system of iron and steel plant so that the water supply is self-sufficient. At the same time, the thermal desalination process solves the unavailability of film desalination process due to low temperature in Bohai Bay and develops the technology of deep extraction of liquid salt, forming the technical route of cascade separation and green utilization of valuable elements such as calcium, magnesium, sodium, and bromine in seawater while promoting industrial integration and regionally coordinated development by combining with chemical enterprises.

In the construction of “five-in-one” green recycling system, from design and planning, engineering construction to preparation and operation, all participating departments completed the engineering construction task with quality and quantity guaranteed realized the success of unit joint startup and generator grid connection by overcoming many difficulties like tight construction period, heavy task and difficult construction organization, hence creating a record of commissioning of the same type of unit. The “five-in-one” green recycling system has completed the deep integration of a variety of automatic control systems and created several records at home.

Jingtang Company has always been practicing the concept of circular economy and green development and has been making leading and pioneering exploration and practice in the green utilization of energy in iron and steel enterprises. CCPP successfully passed the performance test. Together with seawater desalination and other projects, they became the world’s first “five-in-one” green recycling system with “gas, heat, electricity, water, and salt.” It is another milestone unlocked for Jingtang Company in the field of circular economy, opening a new pattern of green recycling of low-quality energy, which will effectively promote the reduction of energy cost in the whole system, process, and procedure in iron and steel plant. It is of great significance to further improve of the green manufacturing capacity of Shougang.