Combined cycles allow the most efficient utilisation of fuel energy for power generation and their design allows easy CO2 concentration and subsequent removal.
The objective of the research is to determine the consequences of solid fuel burning in a mixture of oxygen and recycled flue gases in direct pressurized combustion facilities. The influence of flue gas recirculation (mainly CO2) on reactivity will be studied, pollutant emissions and alkali release will be determined in pressurized reactors with the same solid fuels.
The following tasks are proposed to determine the consequence of the recirculation of flue gases. The same solid feedstock in three different high pressure combustion facilities will be used to determine reactivity, pollutant and alkali emissions.
The research project is divided into three tasks:
Task 1 The goal is to obtain accurate data on reactivity of different solid fuels in a high temperature and pressure environment with analysis of flue gases after reaction in a high CO2 content in order to determine the efficiency of flue gas recirculation with the following apparatus: a) Pressurized entrained flow reactor of VTT
b) Pressurized thermobalance of CNRS
c) Pressurized fluidized bed reactor of DMT
d) Atmospheric drop tube furnace of DMT All devices are laboratory-scale reactors for which experimental conditions and fuel quality can be controlled with high accuracy. They cover the entire field of pressurized combustion of solid fuels.
Task 2 The goal is to study the effects of pressure on the formation and destruction of nitrogen oxides (N2O, NO, NO2) at high CO2 content for various experimental conditions, as defined for task 1 using the pressurized entrained flow reactor (VTT) and the pressurized entrained flow reactor (CNRS). The pathway of nitrogen oxide formation from coal nitrogen through NH3 and HCN will be studied. In this task, SO2 concentrations will be determined. The results will be relevant to nitrogen oxide formation in the above pressurized combustion devices for solid fuels. The pressurized entrained flow reactor of VTT and the pressurized thermobalance of CNRS are both equipped with gas analysis by Fourier transform infra red spectroscopy, allowing measurements of all three nitrogen oxides and SO2 . Task 3 Alkali metals are present both as a vapour phase and in dust particles. It is believed that the vapour phase has the most detrimental effect on the turbine blades. Therefore, a measuring technique will be applied which differentiates between vapour and dust alkalies. In the Excimer Laser Induced Fluorescence method (University of Heidelberg) alkali compounds are dissociated in the flue gas by UV laser photolysis. Another approach to alkali level monitoring, based on thermal dissociation of the alkali compounds is presented by VTT with the University of Tampere (Finland). The two methods for measuring alkali compounds will be used in connection with the pressurized entrained reactor of VTT and pressurized fluidized bed combustor and drop tube furnace of DMT.
Funding SchemeCSC - Cost-sharing contracts