Presented case study focuses on the use of liquefied wood in CHP systems, based on different technologies. In analysis, all of the relevant variables that influence the payback time are taken into account. The comparison with several other fuels is performed which all exhibit lower operational support. The analysis is divided into two power ranges – 1MW and 100kW. For the first, in comparison are included also gas turbine, piston engine, ORC and steam turbine, whereas at 100kW, only system based on microturbine and piston engine is tested due to unavailability of other technologies in this power range. The sensitivity analysis is revealing relatively high influence of fuel price on payback time as well as high influence of electric and heat efficiency on ROI. When taking into account the acceptable payback time on the market, which is 5 years, it is possible to determine the brake-even price of liquefied wood. The calculated price could be obtained by choosing the correct formulation of the fuel with sufficiently low (wholesale) feedstock price.
F.01 Acquisition of new practical knowledge, information and skills
COBISS.SI-ID: 13905179Study presents the analysis of velocity field of liquefied wood, mixture of glycerol/diethylene glycol and diesel fuel in the vicinity of the two-fluid nozzle, designed for use in gas turbines. The aim of the study is to identify the influences of different fuels on atomization process and to evaluate the suitability of the tested nozzle for atomization of liquefied wood. Analysis was carried out for different fuel mass flows, different fuel temperatures and atomization air pressure 3,5 and 6,5 bars. For velocity field calculation, toolkit ADMflow was used which calculates the velocities based on advection-diffusion equation. Results revealed significant influence of atomizing air pressure and fuel density and a moderate influence of fuel mass flow on a velocity field. The influence of fuel temperature is minor. The differences are predominantly visible in concentration field, evolution of velocity in axial direction and also in distribution of velocities in distinctive velocity classes. Potential influence of atomization parameters on performance of combustion process in turbine engines suggests that a trade-off between penetration depth of the fuel jet and mixing intensity of the jet with surrounding air would be required by varying the atomization air pressure and by taking into account also fuel density which also influences the evolution of velocity in axial direction and by this influences the penetration depth of the jet into combustion chamber.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 13905435The presented work analyses the influence of production of liquefied wood with elevated pH value on combustion parameters in a laboratory scale gas turbine. The partially neutralized formulation of liquefied wood is prepared from formulation with reactant ratios (1:1,5:1,5 – wood:glycerol:diethylene glycol) and para-toluensulfonic acid as a catalyst. The quantity of catalyst was 3% of mass of glycols, which gives a final pH of the base formulation 2,5. Partial neutralization of acid catalyst was performed with ammonium hydroxide after successfully terminated liquefaction process. The preferred bases are those that do not contain metals, which is in line with the aim to introduce as few ash precursors in to the fuel as possible. Partially neutralized liquefied wood could exhibit increased stability during storage and has lower impact on process materials exposed to liquefied wood with high temperature. The combustion characterization revealed that thermodynamic parameters of gas turbine, fired with neutralized liquefied wood are comparable to those with base formulation, whereas for emissions, only NOx exhibits different trends. NOx emissions are elevated with neutralized liquefied wood, which is a consequence of higher content of nitrogen, introduced in the fuel with ammonium hydroxide. The efficiency of conversion of fuel-bound nitrogen into NOx is usually relatively high during combustion. In the case of liquefied wood it is roughly 33%, which results in 20ppm higher NOx over entire operating range of the experimental turbine. The results indicate, that in case of significant technical advantages in fuel preparation process, neutralization might prove feasible even if NOx concentration increases.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 13905947