Waste Heat Recovery

As much as 20 to 50% of industrial energy consumption is expended in waste heat. Recovering this heat increases efficiency, saves money, and lessens environmental impact. Facilities can reduce losses by improving equipment efficiency or using recovery technologies. Sources of waste heat include hot combustion gases discharged to the atmosphere, heated products exiting industrial processes, and heat transfer from hot equipment surfaces. Waste heat can be captured and used in industrial processes for heating or for generating mechanical or electrical energy. Uses for recovered heat include:

  • Combustion air preheating
  • Boiler feedwater preheating
  • Load preheating
  • Power generation
  • Steam generation for use in power generation or mechanical power
  • Process steam
  • Space heating
  • Water preheating
  • Transfer to liquid or gaseous process streams

Boiler Stack Economizers

A boiler stack economizer can immediately reduce your fuel costs and carbon footprint. By using flue gas heat to pre-heat feed water going to the boiler, a standard economizer lowers the fuel required to generate steam or heating hot water, and will typically improve system efficiency by 5%. A condensing economizer can provide efficiency gains from 10% to 12% by taking in cooler water temperatures and allowing the flue gas to condense, thereby absorbing more heat energy. There are also two stage economizers to allow two separate water streams to be heated simultaneously. Cannon Boiler Works is a market leader in waste heat recovery systems, industrial heat exchangers and steam accumulators.

Heat Recovery Steam Generators

Heat Recovery Steam Generators (HRSGs) convert heat from gas turbine generators and other heat sources to provide plant steam for industrial and power utility companies. English Boiler designs and builds HRSGs for gas turbines rated to 0.5 to 10.0 Megawatts, and waste heat recovery HRSGs for steam generation up to 1,500 PSIG. Designed and built with a 100% water-cooled wall construction, these systems are available in cross-drum or slant-drum configurations, and for multiple pressure levels. Duct burners are available to use natural gas and oils to supplement the waste heat stream and maintain a constant output. economizer lowers the fuel required to generate steam or heating

Heat Recovery Boilers

Superior Boiler offers industry-leading technology in waste heat recovery boilers, and provides the greatest flexibility of any manufacturer in selecting a system designed to meet specific job requirements and to provide optimum performance and maximize energy savings. Waste heat from a variety of sources can be captured and used to generate steam or hot water for process and comfort heating applications. Superior Boiler Works designs and manufactures customized systems for specific applications, with pressures from 15 to 300 PSIG steam and 30 to 160 PSIG hot water.

Heat Exchangers

A wide variety of heat exchanger designs are available for waste heat recovery, and RJ Mechanical can design and fabricate heat exchanger skid systems to help customers save energy through efficient heat transfer. These systems can incorporate heat exchangers, pumps, valves, sensors and controls for a turn-key solution to money-saving opportunities.

Shell & tube heat exchangers are designed with a series of tubes, or a “tube bundle” which contains one of the process mediums. This tube bundle is inserted into a vessel, or a “shell” which contains the other process medium. Shell & Tube heat exchangers are available in a wide variety of sizes, materials and pressure classes for many applications.

Shell & Coil heat exchangers operate similarly to shell and tube heat exchangers, except that the tube side is a series of smaller coils arranged in a spiral formation, which provide an increased surface area for heat transfer to take place. Also, these units are installed vertically, which takes up less space than a conventional shell and tube heat exchanger. This design makes for a more efficient, cost-effective and space saving alternative to traditional designs.

Plate & Frame heat exchangers utilize a series of thin, flat metal “plates” that are stacked between gaskets and compressed between two “frames”. The gaskets and plates are oriented so that one fluid medium flows through every other gap between the plates, and the other fluid medium flows through the remaining gaps. This arrangement maximizes the heat transfer surface area between the two mediums, and is highly efficient compared to other designs.

Brazed Plate Heat Exchangers: Because the gasket materials in the plate and frame heat exchangers limit the temperatures that can be utilized, a variation of this design is the brazed plate heat exchanger. AIC provides several sizes and configurations of their L series brazed plate heat exchangers. These provide an additional benefit of sealing the edges of the plates together to prevent leakage of process media, which makes it suitable for refrigerants and other liquids.

Links: Heat Recovery