NOTE: Restrictions are in place to limit access to one or more of the files associated with this item. Authorized users must log in to gain access. Non-authorized users do not have access to these files.
Visit the Energy Systems Laboratory Homepage.
Energy Economizer for Low Temperature Stack Gas: A Case Study
MetadataShow full item record
Bartlesville (Oklahoma) Energy Technology Center (BETC) engineers made a study of recycling waste heat from one of the Power Plant boilers. The study showed that a system could be designed that would reclaim this waste heat and then utilize it to preheat air for boiler operation. The system incorporated a heat pipe heat exchanger flanged in a stack by-pass loop that would efficiently capture and transfer heat at low temperature differences (?T 350-5000 F). After reclaiming heat from this source, the burner air supply is preheated by passing through the heat exchanger. Sensitive design problems that had to be resolved were: Overall cost-effectiveness; below dew point cooling of stack gas causing acid corrosion; and selection of an effective heat exchanger for this application The candidate boiler is one of two that generate high temperature hot water (HTHW) for BETC facility heating and cooling. One unit normally handles the heating and cooling load while the other is in standby status. The preheat system was designed by BETC engineers. The new stack assembly was fabricated by a local metal shop, and was installed by BETC maintenance personnel. The cost of the heat exchanger and other hard-ware was $7,562. Operational results show that boiler efficiency has increased between 6 and 7 percent, which reflects the percent of reduction in fuel consumption. At full-load conditions, the burner supply air is preheated to 350oF and stack gas is cooled to 310oF. Corrosion damage to the heat exchanger and other internal parts are non-existent. Natural gas is the boiler fuel, and as expected, no residue coating of the heat exchanger has developed. To date, we are well pleased with the performance of the system. The savings in fuel and dollars speaks for itself. We are optimistic that this approach of reclaiming heat is not only technically feasible, but also cost-effective for many industry boilers that emit low temperature stack gas.
Tipton, J. A. (1979). Energy Economizer for Low Temperature Stack Gas: A Case Study. Energy Systems Laboratory (http://esl.tamu.edu). Available electronically from