Industrial waste heat recovery refers to the technical system that collects and reuses the thermal energy generated during industrial production but not effectively utilized. As a core means of industrial energy conservation and achieving the "dual carbon" goals, its core value lies in converting waste heat energy into usable energy, thereby significantly improving energy efficiency, reducing carbon emissions, and generating economic benefits.

 

Industrial waste heat resources widely exist in high-energy-consuming industries such as steel, cement, chemical, and power. Their forms include high-temperature flue gas, steam, hot water, high-temperature products, and slag, with temperature ranges from tens of degrees Celsius to over 1500°C. According to evaluations, such waste heat accounts for approximately 30% to 50% of total industrial energy consumption, of which the recyclable amount reaches about 60% of the total waste heat resources. Full development can save about 200 million tons of standard coal annually and reduce carbon dioxide emissions by about 500 million tons.

 

The waste heat recovery technology system is mainly divided into the following categories:

 

Firstly, heat exchanger and waste heat boiler technology, which transfers waste heat from high-temperature medium to low-temperature medium through heat exchange equipment to achieve direct reuse of heat. This technology is mature and low-cost, especially suitable for high-temperature flue gas recovery in industries such as steel and cement, but it needs to address the challenges of heat source stability and volatility.

 

Secondly, waste heat power generation technology, including steam turbine power generation and Organic Rankine Cycle (ORC) power generation. Steam turbine power generation is suitable for high-temperature waste heat above 300°C, using waste heat boilers to generate steam to drive turbines for power generation. ORC power generation targets medium and low-temperature waste heat of 100~300°C, using low-boiling organic working fluids to achieve heat-to-electricity conversion, and is widely used in wastewater and low-pressure steam recovery in chemical, power and other industries.

 

Thirdly, innovative application of heat pump technology, which raises low-temperature hot water at 20-30°C to above 55°C as a heating source for air conditioning systems, realizing efficient utilization of low-grade waste heat. Heat pump systems can switch multiple working modes, significantly reducing steam consumption and improving energy utilization efficiency.

 

In addition, there is waste heat-driven refrigeration technology, which uses waste heat as the driving energy for refrigeration to improve the cascade utilization efficiency of energy. And heat pipe technology, which realizes large heat transport under extremely small temperature differences through phase change principles, especially suitable for complex working conditions containing dust and corrosive media.

 

Current industrial waste heat recovery faces multiple challenges such as large waste heat volatility, complex working conditions, equipment adaptability, and economy. Future technological development focuses on high efficiency of heat exchangers, innovative applications of heat pump and heat pipe technologies, intelligent system integration, and improvement of material corrosion resistance. At the policy level, supportive measures are continuously introduced to promote the improvement of industry standards and technology promotion.

 

Waste heat utilization projects have significant economic and environmental benefits. In terms of economic benefits, they can significantly reduce enterprise energy costs, and the investment return period continues to shorten as technology matures. In terms of environmental benefits, they effectively reduce greenhouse gas and pollutant emissions, providing strong support for industrial green transformation.

 

Through technological optimization and policy guidance, industrial waste heat recovery is gradually becoming a core means of energy conservation and carbon reduction in the industrial field. In the future, it is necessary to further break through technical bottlenecks, strengthen system integration, to release its whole industry chain potential, and make greater contributions to achieving the dual carbon goals.