A Case Study on the Electricity Generation Using a Micro Gas Turbine Fuelled by Biogas from a Sewage Treatment Plant

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 (ηEB) 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.

Biogas upgrading, economy and utilization: a review

“…These released gases were significantly less than the emission level of the stationary sources set for Taiwan, which corresponds to 150 ppmv and 2,000 ppmv, respectively. The research, therefore, proved that utilizing biogas for small gas turbine power generators did not only demonstrate promising results but also performed very well in reducing greenhouse gas emissions, leading towards an environmentally and economic friendly concept (Chang et al 2019). Biogas is a renewable and environmentally friendly fuel.…”

Subcritical Hydrothermal Co-Liquefaction of Process Rejects at a Wastepaper-Based Paper Mill with Waste Soybean Oil

“…into a crude bio-oil product and a gaseous product via hydrothermal processing [26]. The constituents of a crude bio-oil product include phenol and its alkylated derivatives [27], heterocyclic N-containing compounds [28], long-chain fatty acids, alkanes and alkenes, and derivatives of phytol and cholesterol [29,30]. Some compounds are the same as this study.…”

A Mathematical Model for the Optimization of Renewable Energy Systems

“…There is literature that focuses on mathematical models for the design of SIRESs. Some of these investigations are comprised of simulations [13,14], linear programming [15][16][17], objective programming [18,19], optimized analysis and planning for power generation [20], and a probabilistic approach that takes into account the probability of power leakage [21]. A chronological simulation demands large amounts of data on resources and loads that are obtained from local requirements, oriented towards linear programming (LP) and objective programming (OP) and a deterministic use of annual or seasonal average values in its analysis [22].…”