Making heat more efficient can create energy savings

By Tim Albrecht | June 11, 2018

The first-ever Efficient Ethanol Production Seminar preconference at the International Fuel Ethanol Workshop & Expo kicked off this morning with a panel titled, “Surveying the Untapped Potential for Energy Savings via the More Efficient Use of Process Heat.” Speakers on the panel included Tim Kuznetsov, technology director-water for Buckman International, Evan Almberg, analysis engineer for HRST Inc., and Bill Schafer, CEO of Energy Integration Inc.

The panel focused methods and technologies that can increase efficiency of heat created during production, decreasing the amount of energy expended and the carbon footprint of each gallon produced.

Kuzetsov began the panel discussing ways to increase thin stillage evaporator efficiency through improved control of organic fouling. Those increased fouling rates can occur because of higher stillage solids and high steam rates. Fouling can affect corn oil production, Kuzetov said.

Buckman developed the Bulab 8170GR to control evaporation deposits that form due to organic fouling. The 8170 is effective on both organic and inorganic components, Kuzetov said. “As case history can attest, the 8170 delivers savings in steam, chemical, man power costs, reduces employee safety risks and downtime, helping produce more gallons of ethanol.”

Almberg discussed, inspection priority, doing analysis on the heat recovery steam generator (HRSG) from both a design and thermal standpoint, as well as solving reliability and performance issues.

HRSG is the heart or center of the process operation, supplying energy and steam throughout the ethanol process. Because of this, and natural gas being one of the highest operating expenses, “being able to squeeze out a little bit of efficiency or increase your steam performance can result in a pretty large payback,” Almberg said.

The HRSF can often be overlooked. Priority should be given to rotating equipment assemblies, doing different cleanings in different areas of the plant. These increasing periods between work being done on HRSGs can be detrimental. Without getting in and doing inspections, it can lead to failures, Almberg said.

Schafer brought the panel to a close discussing mechanical vapor regeneration (MVR) and how to reduce plant energy usage by half via that MVR. It’s a large hurdle that Energy Integration has to deal with and “people are rightly skeptical,” Schafer said. “It’s not an exaggeration and it’s very doable.”

MVR and evaporation isn’t a “new, exciting thing.” In other industries “MVR is kind of old hat.” A lot of the companies that do lysine, amino acids and MSG use MVR, as well as food processors and dairies. For them it’s typically applied through a single process. The MVR challenge in our industry is we have designs that incorporate multiple effects and cascade heat between process blocks, “this complicates things a bit.” It’s harder to install a MVR in a single process when you already have all this integration energy cascading between process blocks, Schafer said.

The Efficient Ethanol Production Seminar is one of two June 10 preconference seminars at this year’s FEW. The other is the traditional Ethanol 101. The 2018 FEW is being held June 11 to 13 at the CenturyLink Center in Omaha.