TECHNO-ECONOMIC EVALUATION OF RECUPERATED GAS TURBINE COGENERATION CYCLES UTILIZING ANIMAL MANURE AND ENERGY CROPS FOR BIOGAS FUEL

摘要

This work presents the development of an integrated approach, targeting the techno-economic assessment of recuperated cogeneration gas turbine cycles, utilizing anaerobic digestion products of animal manure and energy crops for biogas fuel. The overall approach consists of a series of fundamental modeling theories applicable to; anaerobic digestion and biogas fuel yield, thermodynamic analysis of cogeneration gas turbine cycles, exergetic analysis of anaerobic digestion, and economic modeling of implementation and operation. The developed methodology is applied to the techno-economic analysis of a representative anaerobic digestion plant yielding biogas fuel which is supplied to a recuperated cogeneration gas turbine pow-erplant. The influence of employed thermodynamic cycle parameters along with the incorporated technology level, on the cycle performance parameters and economic sustainability of integrated digestion-cogeneration powerplant designs, is thoroughly investigated. The obtained results suggest that, the dominant thermodynamic cycle variables that affect the electrical performance of integrated digestion-cogeneration systems, are the gas/air temperatures at the combustor outlet and recuperator air side exit, respectively. It is shown that the profitability of the investment is highly depended on the electrical power output and the feed-in tariff for electrical energy. Optimization of the employed cogeneration cycle for maximum electrical power output, is shown to be a crucial element in terms of securing investment sustainability. A general review of the results indicates that, anaerobic treatment of animal manure and energy crops may constitute a sustainable investment, primarily for cases that substantial volumes of substrates are available in order to secure biogas yield and stable operation of the AD-gas turbine power plant.