Many of the world’s industries have been recovering heat from exhaust gases for decades. For instance, in both metal and plastics processing, producers often recover heat from flue gases emitted from the production processes. The recovered heat can be reused or converted into electrical energy or steam.
In many industrial processes, bulk granular solids undergo thermal treatment to meet or provide final product specifications. For example, calcination is a high temperature process that removes oxygen and volatiles to produce high quality cement and other refractory materials.
At pulp-and-paper mills, drying the paper products is an integral component in producing the highest quality paper possible. The drying process consumes more than 60 percent of the total energy demands of the papermaking process.
Tangshan Zhengfeng Iron & Steel Co. ordered three intelligent waste-heat recovery systems. Designed and supplied by Tenova, a Techint Group company, the iRecovery system is designed for use with electric steelmaking production, among other processes.
Applying a centrifugal heat pump and absorption heat pumps to recover waste heat from the cooling water of the power plant steam condenser allowed one city to avoid the cost and emissions of coal-fired district heating.
In 2017, the China Development and Reform Commission issued the Northern China Winter Clean Heating Plan. It mandated that, by the end of 2021, clean combustion of coal in thermal power plants would be used to provide 8 billion square meters of heating area. Estimates say this will account for nearly 40 percent of the total clean-heating area in northern China in 2021.
Recent energy cost increases and the introduction of anaerobic thermophilic processes as part of wasted industrial process and municipal-sludge digestion has prompted the use of heat recovery exchangers.
Sigma Thermal, a manufacturer of biomass-fired energy systems and waste-heat recovery systems, is using solar power to supplement roughly half of its electricity needs during peak consumption times and nearly 100 percent in lower consumption periods.
A commercially viable turbo-compression cooling system for ultra-low temperature waste heat recovery shows promise for industrial applications. For example, a dairy producer could transform the waste heat generated when they pasteurize their milk and put it to work chilling the milk.
Recapturing waste heat allows you to capture thermal energy you would otherwise let escape up the stack and put it to work in your process. Air-to-air heat exchangers provide an effective means of capturing this otherwise lost resource.
With an ever-increasing focus on energy efficiency and improving system performance, industrial processors are looking for ways to achieve these goals while reducing costs and material usage wherever possible.