Finding Equipment That Suits Your Process
Jay Hudson, P.E., president of J.G. Hudson & Associates, Charlotte, a specialty engineering firm concentrating in process-related engineering services, continues his six-part series on specifying a thermal fluid heating system with “Fired Thermal Fluid Heaters.” In answer to that oft-asked question, “What makes a good thermal fluid heater?”, Hudson explains how understanding your process and its specifics, including the required fluid flow rate, process fluid temperature setpoint, fluid allowable film temperature, emission restrictions, and what add-ons are needed to enhance combustion efficiency, will identify the system you need. Beginning on page 21, Hudson discusses the challenges involved in properly specifying and selecting a direct-fired thermal fluid heater.
In “Understanding Boiler Fuel Efficiency,” Eric A. Kessler, Eastern regional sales manager for Clayton Industries, City of Industry, Calif., explains both why boiler efficiency is important and how to maximize it. Kessler notes that steam systems account for 30 percent of industry’s energy consumption and represent a significant investment: nearly $46 billion is spent per year in the United States alone to make steam. In addition, for a typical industrial process heating application, the annual fuel bill is likely to be two to three times the installed cost of any new boiler. Therefore, the first year’s savings with the more fuel-efficient unit can easily exceed the difference in installed cost. Keeping this fact -- and others, explained beginning on page 31 -- in mind will help you make a smart steam system choice.
Time and temperature are two factors that help determine how much energy a process heat application demands. Even applications at relatively low temperatures can consume large amounts of energy if the process is long. Malt houses for beer-making are one example of such a process. As Jürgen Breier, a technical writer for Schott AG, explains in “Hot Air for Cold Beer,” which begins on page 38, the air inside the drying plants in modern malt houses is heated indirectly to temperatures as high as 212 oF (100oC). Natural gas burners produce a hot gas that heats up the air indirectly using a heat exchanger that contains bundles of steel tubes. Indirect heating ensures that the malt remains free from the combustion products of fossil fuels. Breier describes how adding a glass-tube heat exchanger for heat recovery can reduce energy costs for malt houses.
Finally, in “Free Cooling for Process Applications,” Graham Whitmore, president of Motivair Corp., Amherst, N.Y., explains how year-round industrial process heating applications requiring cooling can benefit from a chiller with a winter economizer system designed to take advantage of cold outside temperatures. At the same time the useful equipment life is extended through selectively beneficial and reduced operating hours.
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