Practice of Green Economy in the Development Trend of Qinggang

1、 Preface

The steel industry is a major consumer of resources and power, accounting for approximately 14% of the country’s energy consumption, and is also a major emitter of pollutants. Therefore, it is imperative for steel manufacturers to explore the establishment of a circular economy model and establish resource saving and environmentally friendly manufacturers.
Qingdao Iron and Steel Holding Group Co., Ltd. (referred to as Qingdao Iron and Steel) is an old manufacturer with a history of over 40 years. Under the traditional economic model, it has always been on the brink of a vicious cycle of “outdated and outdated equipment – high material consumption – high cost – high pollution – low efficiency”. Many valuable resources and secondary power have not been effectively utilized, resulting in the waste of resources and power, as well as environmental pollution, affecting the development and image of the manufacturer. Since the Ninth Five Year Plan, Qinggang has deeply realized that without the advantages of energy conservation, there will be no advantages of environmental protection, and without sustainable development of the environment, there will be no sustainable development of manufacturers. Therefore, Qinggang has taken practical measures, using technological innovation and transformation projects as carriers, actively improving cnc machining supporting facilities, screening outdated production processes, vigorously promoting the recovery and utilization of secondary power and resources, actively exploring the circular economy model, and starting to complete the closed cycle and induction application of gas, water, residual heat energy, and solid waste, completing the recycling of single process waste throughout the company’s production process; By innovating in the region and exploring new technologies for resource utilization of chemical hazardous waste – chromium slag, we have established a regional circular industrial chain and achieved a win-win situation in terms of economic, social, and environmental benefits.

2、 Relying on technological transformation to complete the induction and utilization of resource power

Manufacturers are the main players in the development of circular economy, and they need to minimize resource utilization to the greatest extent possible, as well as achieve waste recycling, reduction, and harmless treatment. In recent years, Qinggang has embarked on large-scale technological transformation by reducing power and resource consumption, and has begun to complete the closed cycle and induction utilization of gas, water, waste heat and energy, and solid waste. It has established an internal circular economy model of the company, with significant results.

（1） Recovery of blast furnace gas and converter gas

1. Since the production of the 1 # and 2 # blast furnaces in Qinggang, the recovery and utilization of blast furnace gas have resulted in the high altitude release of all the remaining gas, except for the hot blast furnace. This has not only caused great waste of power but also polluted the atmospheric environment. Since 1998, Qinggang has invested more than 80 million yuan and completed the project of converting 6 coal-fired boilers and 4 oil-fired heating furnaces to coal gas (during which 1 was converted to oil gas mixed combustion); Using the domestically advanced dual preheating and automatic recovery regenerative heat sink furnace with fully burned blast furnace gas, 100% utilization of blast furnace gas is achieved, and the gas is heated to 700 ℃ using waste gas heat before being burned in the furnace hall, greatly improving thermal efficiency. Currently, Qinggang has a total of 6 blast furnaces, with a blast furnace gas output of 665000 m3/h. The utilization rate of blast furnace gas has increased from 45% in 1997 to over 92% in 2005. It has replaced heavy oil by 131300 tons in the past year, reduced material cost by 30 yuan per ton, and generated an annual total benefit of 390 million yuan. In July 2005, a 50 million yuan lime rotary kiln was put into operation, with a planned daily output of 600 tons of lime. The kiln incinerates converter gas or blast furnace gas to replace coke, saving 170 meters of coke per ton of lime