PDF Publication Title:
Text from PDF Page: 040
Chapter 2 Evaluation of Combined Heat and Power Technologies for Wastewater Treatment Facilities 2.4.2 Heat Recovery In contrast to the previously described CHP technologies that produce heat by fuel combustion, fuel cells are driven by electrochemical reactions. The electrochemical reactions that occur within fuel cells are exothermic, meaning that heat is evolved from the reaction. In addition to heat, the electrochemical reactions also produce water. The heat generated by the electrochemical reaction is sufficient to immediately vaporize the water formed during the same chemical reaction. Heat produced by the electrochemical reaction is available for digester heating but rarely in sufficient amounts to supply the entire amount of heat required by the digestion process. Most fuel cell based CHP systems require a boiler to make up the shortfall of heat energy not provided by the fuel cells thus maintaining the anaerobic digesters at the appropriate temperature. Boilers found at POTWs generally operate with either digester gas or natural gas. Therefore, the use of a boiler to supplement POTW heating needs decreases the overall CHP system efficiency and does not maximize the energy available in anaerobic digester gas. PAFCs operate at about 350 degrees F and produce low grade heat suitable for anaerobic digester heating with hot water. MCFCs operate at much higher temperatures, reaching about 1,250 degrees F. In addition to anaerobic digester heating, the recoverable heat from MCFCs is also capable of producing sufficient high- pressure steam to drive a steam turbine, generating additional power. A process flow diagram of a general fuel cell CHP system is shown on Figure 2-7. Figure 2-7. Process Flow Diagram of Typical Fuel Cell System 2.4.3 Exhaust Emissions Fuel cells represent the CHP technology with the lowest exhaust emissions. This is because fuel cells rely primarily on electrochemical reactions to convert fuel into hydrogen with only a small amount of fuel being combusted to produce steam for the reformer. Given their extremely clean emissions, the authors are not aware of any jurisdictions within the United States that require air permitting for fuel cells. Table 2-4 summarizes the advantages and disadvantages associated with fuel cell technology. 2-15PDF Image | Combined Heat and Power Technologies for Wastewater Facilities
PDF Search Title:
Combined Heat and Power Technologies for Wastewater FacilitiesOriginal File Name Searched:
300_CHP-EPA-w-Apps.pdfDIY PDF Search: Google It | Yahoo | Bing
Capstone Turbine and Microturbine: Capstone microturbines used and new surplus for sale listing More Info
Consulting and Strategy Services: Need help with Capstone Turbine, sizing systems, applications, or renewable energy strategy, we are here to assist More Info
Container Lumber Dry Kiln: Since 1991 developing and innovating dry kilns using standard shipping containers More Info
Supercritical CO2 Lumber Dry Kiln: Compact fast drying in 3 days or less for small amounts of wood and lumber drying More Info
BitCoin Mining: Bitcoin Mining and Cryptocurrency... More Info
Publications: Capstone Turbine publications for microturbine and distributed energy More Info
FileMaker Software for Renewable Energy Developing database software for the renewable energy industry More Info
CO2 Gas to Liquids On-Demand Production Cart Developing a supercritical CO2 to alcohol on-demand production system (via Nafion reverse fuel cell) More Info
Stranded Gas for low cost power Bitcoin Mining Using stranded gas for generators may provide breakthrough low power costs for cryptocurrency miners. More Info
CONTACT TEL: 608-238-6001 Email: greg@globalmicroturbine.com (Standard Web Page)