Opportunities for heat recovery and reuse abound. Regular readers of this column may recall that in January, I shared how researchers at Penn State University are exploring methods for harvesting low grade waste heat as electricity using reversible ammonia batteries. Power plants use steam to produce electricity, but after producing electricity, the excess heat is routed to cooling towers. Most industrial process heating operations produce heat that, while needed for specific steps and equipment in the process, also must be extracted, dissipated or cooled elsewhere in the process.
While the potential for heat recovery is fairly easy to find, finding the means to capture and reuse that heat on terms that provide a reasonable financial payback is seldom so easy. In “Condensing Heat Recovery for Industrial Process Applications,” Robert Triebe, the COO of Thermal Energy International Inc., Ottawa, Ontario, tackles this problem by offering an eight-step approach to identifying and quantifying heat recovery projects with the greatest economical and practical benefits. While Triebe focuses of condensing heat recovery technologies, the evaluation and selection process described is nearly universal.
Waste heat recovery also is possible from your pollution control equipment. If you are using an oxidizer to destroy small particulate matter as well as airborne volatile organic compounds (VOCs), without heat recovery, you are sending valuable BTUs up the exhaust stack. While the best oxidizer for your plant depends on a number of factors, in “Finding an Oxidizer for Your Process Plant,” Brian Wendt, an environmental specialist with Epcon Industrial Systems LP, The Woodlands, Texas, provides an overview of your options, including those for heat recovery.
Elsewhere in this issue, Mark Lampe, a product marketing manager for industrial and commercial combustion at Honeywell Environmental and Combustion Division, Muncie, Ind., offers advice on how to ensure that a combustion system is operating at its highest potential efficiency. Unfortunately, sometimes outdated or poorly designed equipment result in unacceptably high efficiency losses and energy costs. If even the best tuned version of the equipment you have cannot do the job, Lampe explains how modifying combustion settings (safely, of course!) and even replacing the burner can improve your bottom line.
Of course, replacing the process heating equipment is not the only way to improve process performance. Upgrading temperature sensors and controls — whether it’s from discrete temperature controllers to those driven by a programmable logic controller (PLC) or more sophisticated controls with associated data-acquisition systems — may better identify over- or under-temperature conditions, isolate areas of heat loss, and allow you to reduce process times. Frank Geracie, a senior application engineer at Wisconsin Oven, East Troy, Wis., takes a look at process controls that recognize and respond to part temperature rather than oven chamber temperature in his article, “Advanced Thermal Process Controls Provide Benefits.”