By replacing aging coal boilers, generating electricity on-site, and recovering heat, overall energy efficiency has been boosted while substantially reducing energy costs and cutting water usage by 5%.
Five years ago, Tate & Lyle decided to replace an aging coal boiler at its Loudon corn milling facility in Tennessee. It switched to natural gas-based combined heat and power (CHP). The drivers were simple: The rising price of coal and stricter emissions requirements would necessitate the addition of expensive pollution control equipment on its coal boilers. Instead of investing in flue gas desulfurization (FGD) and selective catalytic reduction (SCR) technology to stay within boiler maximum achievable control technology (MACT) limits, the company decided to spend a little more to revamp and expand its steam and electricity production capabilities.
Tate & Lyle built a new natural gas-fired generating plant in tandem with waste heat boiler technology to boost efficiency, lower emissions, and satisfy its steam requirements. That facility consisted of two SGT-700 gas turbines and two SGen-100A generators from Siemens Energy as well as heat recovery steam generators (HRSGs) with supplemental duct firing from Rentech Boiler Systems. This not only improved energy and operational efficiency, it reduced greenhouse gas emissions by nearly 50% and slashed companywide CO2 emissions by around 10%.