Will resource recycling & waste heat power generation become the key to helping companies break through?

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　 Waste heat is the energy that remains unused in energy utilization equipment under certain economic and technical conditions; in other words, it is excess or discarded energy. According to investigations, the total waste heat resources in various industries account for approximately 17%–67% of their total fuel consumption, and the waste heat resources that can be recovered make up about 60% of the total waste heat resources. Waste heat power generation not only saves energy but also contributes to environmental protection, offering broad market prospects. 60% of the resources can still be recycled; the waste heat power generation industry holds great potential. During the firing process of bricks made from coal gangue, a large amount of heat is generated, which is discharged outside the kiln through exhaust fans – mainly as waste heat from the flue gas and waste heat resulting from the cooling of the products. According to investigations, the total amount of waste heat generated in sintered brick production accounts for approximately 30%-60% of its total fuel consumption, and the waste heat that can be recovered constitutes about 40% of the total waste heat available. At present, this portion of heat is not effectively utilized, except for being mixed with some cold air to cool it down to around 125°C for drying the brick blanks. These hot gases have a flue gas temperature of up to 400°C in their hottest sections, with an average temperature of around 200°C; they constitute an excellent source of stable low-temperature heat and hold potential for generating electricity from waste heat. If adopted nationwide, they would offer broad market prospects. 　　Current Status of the Waste Heat Power Generation Industry in China Waste heat refers to energy that remains unused in energy utilization equipment under certain economic and technical conditions; in other words, it is excess or wasted energy. It includes seven types: waste heat from high-temperature exhaust gases, waste heat from cooling media, waste heat from exhaust gases and wastewater, waste heat from high-temperature products and slag, waste heat from chemical reactions, waste heat from combustible exhaust gases, liquids and wastes, as well as the residual pressure of high-pressure fluids. According to investigations, the total waste heat resources in various industries account for approximately 17%–67% of their total fuel consumption, and the waste heat resources that can be recovered make up about 60% of the total waste heat resources. 　　In industry, waste heat is generally prioritized for use in production processes. When there is a surplus, although direct utilization (such as for HVAC systems or as power) results in a higher energy efficiency, this approach has certain limitations due to the relatively low demand for HVAC systems and the significant seasonal variations in that demand, as well as the need for relatively stable loads when using heat as power. 　　More often, the technology of waste heat power generation is chosen to recycle energy. The so-called waste heat power generation technology is a technique that converts excess thermal energy from the production process into electrical energy. Waste heat power generation not only saves energy but also contributes to environmental protection. 　　The key equipment for waste heat power generation is the waste heat boiler. It uses the heat or combustible materials in waste gases, waste liquids, and other fluids as a heat source to generate steam for power production. Due to the low temperature of the working fluid, the boiler is large in size and requires a lot of metal. The waste heat used for power generation mainly includes: waste heat from high-temperature flue gas, waste heat from chemical reactions, waste heat from exhaust gases and wastewater, as well as low-temperature waste heat (below 200°C). 　　With the increasing awareness of energy conservation and environmental protection, preheaters and low-temperature waste heat power generation systems designed solely for the utilization of waste heat saw significant development around the early 1980s. Taking cement waste heat power generation as an example, the temperature of the exhaust gases from cement kilns is around 350°C, and the heat consumption per kilogram of clinker is 2900–3300 kJ/kg. The power generation capacity of the associated low-temperature waste heat power generation systems is 30–40 kW per ton of clinker, which is of great significance for cement companies in terms of comprehensive utilization of resources and improving economic efficiency. 　　The application of this technology can not only reduce the production costs of cement and improve the economic efficiency of enterprises, but also help save a large amount of electrical energy and reduce environmental pollution; thus, it has broad prospects for widespread adoption.