A case study on the electricity generation using a micro gas turbine fuelled by biogas from a sewage treatment plant
Journal
Energies
Journal Volume
12
Journal Issue
12
Date Issued
2019
Author(s)
Chang, C.-C.
Do, M.V.
Hsu, W.-L.
Liu, B.-L.
Chang, C.-Y.
Chen, Y.-H.
Yuan, M.-H.
Lin, C.-F.
Yu, C.-P.
Chen, Y.-H.
Shie, J.-L.
Wu, W.-Y.
Lee, C.-H.
Abstract
Combined heat and power production from biogas is now playing an important role in energy and resource utilization as well as pollution control in waste water treatment. This research used biogas from the Bali Sewage Treatment Plant in New Taipei City, Taiwan, as a major source of fuel for the electricity generation. A micro gas turbine electricity generator, Capstone CR-30, which possesses a maximum rated power load (PWL) of 30 kW, was equipped to convert biogas into electricity. The biogas is mainly composed of CH4 (56.1 ± 8.0 vol.%), CO2 (25.5 ± 9.8 vol.%), H2 (0.5 vol.%), and H2S (0.99 ± 0.07 ppmv). During the test operation period of the generator, it was found that the thermal efficiency increases from 19.8% to 23.4% kWhe/kWhth, while the electricity generation efficiency (νEB) also rises from 0.93 to 1.09 kWhe/m3 biogas as the PWL increases from 10 kW to 30 kW. The results indicated that the generator has a better performance with higher PWL. At PWL = 30 kW, the average adjusted concentrations of CO and NOx (adjusted to 15 vol.% O2) emitted from the generator are 86 ppmv and 17 ppmv, respectively. Both are much lower than the emission standards of stationary sources in Taiwan of 2000 ppmv and 150 ppmv, respectively. Thus, PWL of 30 kW was selected in cooperation with biogas inflow = 0.412 m3/min and air/fuel ratio (i.e., air/biogas ratio) = 76.0 vol./vol. for the long-term regular operation. At the above setting conditions for long-term operation, the generator continuously consumed the biogas and provided stable electricity generation at a rate of 19.64 kWhe/h for a 2-year running period. Moreover, the greenhouse gas can be cut off with a rate of 10.78 kg CO2e/h when using biogas as fuel for electricity generation. Overall, this research proves that the application of a micro gas turbine electricity generator not only has promising performance for using biogas but also gives a significant reduction of greenhouse gas emission, which fits the concepts of the circular economy and environmental protection. © 2019 by the authors.
Other Subjects
Air pollution control; Air quality; Biogas; Electric equipment protection; Electric generators; Gas turbines; Greenhouse gases; Piecewise linear techniques; Sewage treatment; Sewage treatment plants; Waste treatment; Wastewater treatment; Water pollution; Water pollution control; Water treatment; Biogas conversions; Combined heat and power production; Electricity generation; Electricity generation efficiencies; Electricity generators; Greenhouse gas reductions; Regular operations; Resource utilizations; Electric power generation
Type
journal article