Duke University in Durham, NC, spent $35 million on the conversion of its West Campus Steam Plant to natural gas from a coal plant that burned more than 50,000 tons of coal a year.
An article in HPAC Engineering says the plant, which was built in 1928, provides steam for space and process heating for more than 7 million square feet of facilities. The plant contains six boilers and can produce up to 420,000 pounds of steam per hour at 150 psig.
By converting to natural gas, the university was able to demolish coal infrastructure, including baghouses, ash silos and lime silos.
The new West Campus Steam Plant includes a custom flue-gas heat-recovery system, which uses energy from stack gas to boost condensate return temperature and preheat makeup water upstream of its entry point at the deaerator, according to HPAC Engineering. Plant energy savings and extra unfired capacity during summer is 4,000 MBH, while winter recovery rates can climb to more than 10,000 MBH. Boosted by energy recovery and near-year-round base-load hours, new Boiler 1’s and new Boiler 2’s annual fuel-to-steam efficiencies are expected to be nearly 90 percent, says the article.