2.3 MW biomass steam power plant: Experimental and thermodynamic analysis

Abstract

The present paper shows the experimental and numerical analysis of a biomass plant from maximum power of 2.3 MW. This is a classical Steam Power Plant with a maximum pressure of 48 bar and a turbine inlet temperature of about 430 °C at the design point. The size is significantly smaller than the mean of this type of system [1], [2], [3], [4],, but maintains a relative high value (about 22.9%) of the Global Electric Efficiency. The analysis was conducted using experimental data, collected directly on the Power Plant, at the Design Point, and thus validating thermodynamic models. The difficulty in collecting the experimental data of this type of system, is mainly due to the enormous variability of the lower heating value of biomass, which involves a large variability of the load and then the operating parameters. Combustion simulation was validated by experimental data (Flue gas temperature, air flow, fuel flow) and the results allowed the evaluation of the biomass composition that is within the range reported in the literature [5]. Different Plant configurations were, numerically, evaluated to plug the power fluctuations due to variability of biomass. A 100 kWe Natural Gas fuelled Micro-Gas Turbine (MGT) was numerically connected to the Biomass Steam Power Plant (BSPP) to evaluate the benefits on the power fluctuations and on the Global Electric Efficiency. A MGT thermodynamic scheme has been developed and, properly, validated with experimental data from literature [6] e [7].. It is designed to send the hot gases coming from the exit of the MGT in the combustion chamber of the main system, thus creating a MGT-ST Power Plant. Analysis of the results of this coupling has noticed an improvement in terms of efficiency and operational stability.