GE’s fleet of 47 heavy duty gas turbines operating on low British thermal unit fuels has accumulated more than 2 million fired hours. Low BTU, or low calorific value fuels have significantly less heating values than natural gas. Examples include syngas, steel mill gases and dilute natural gas. These fuels are lighter than natural gas and have less energy per unit volume.
According to the company, the fuel flexibility inherent in GE’s B, E and F-class turbines has allowed these units to operate on low BTU fuels in a variety of applications, including integrated gasification combined-cycle, refinery-based IGCC and steel mills.
Robust operation on low fuels
To achieve the same heat input as natural gas-fired units, low BTU fuels need increased fuel flow. This flow rate requires the fleet to use GE’s Multi Nozzle Quiet Combustion and standard syngas combustors, which provide robust and reliable operation on low BTU fuels.
The hours accumulated by the fleet include projects totaling more than 4 gigawatts of installed power generation capacity at 21 plants. One million of those hours have been achieved on GE’s E-class turbines. Roughly 600,000 hours have been accumulated on GE’s B-class while the remaining 400,000 hours were amassed on the F-class.
Reduction in emissions
A case in point is the Wuhan Iron & Steel Group steel mill near Wuhan City in Hubei Province, China. To comply with China’s goals to reduce energy consumption and emissions, WISCO installed a combined-cycle power plant—powered by two GE 9E Gas Turbines—at the Wuhan mill. Reusing the mill’s own “blast furnace” and “coke oven” waste gases as “free” fuel, the two GE 109 combined-cycle systems each generate 164 megawatts of onsite power to support the mill’s activities. Currently, the power plant’s annual output is 1 billion kWh/a, with a guaranteed electrical efficiency greater than 42 percent.
The key benefits of this project for WISCO include a reduction in emissions associated with the waste gases created during the steel production process and new revenues generated by the sale of some of the power plant’s electricity to the local grid.