Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/7733
Climate change and green energy policies are driving the pursuit for environmentally friendly and thermodynamically efficient technologies. This research work combines renewable energy with the energy efficient concept of combined heat and power (CHP) and the emerging technology of biomass fast pyrolysis. The latter produces valuable bio-oil that can be further upgraded to e.g. transportation fuels or be used in heavy fuel oil boilers.
This thesis focuses on developing steady-state simulation models of different biomass-based CHP integration options with biomass drying and fast pyrolysis. Integration options include the use of a grate fired boiler and a circulating fluidized bed with a boiler-integrated pyrolysis process.. These systems are then analyzed from a thermodynamic and environmental point of view using a multiperiod district heating load model. Assuming the free boiler capacity in part loads is used for the highest possible yields of slurry, bio-oil yield is estimated.
Models developed in this work follow the logic of the previous study on bubbling fluidized bed boiler. The research approach adopted includes a simulation in steady-state thermal power plant simulation software. Environmental performance calculations use modified Primary Energy Factors and CO2 emissions coefficients according to EN15603 and EN 15613-4-5 standards. Results for all studied boiler types are then compared to results from the previous studies and conclusions are drawn. The implementation of the concept in Poland is analyzed.
The key findings provide evidence that by co-generation of a pyrolysis product, operation hours and thus electricity and heat, production can be improved. The integration also improves the district heating network‘s primary energy efficiency and lowers its carbon dioxide emission coefficient. The boiler type does not affect the basic integration concept. Moreover, the benefits of the integration already found for the bubbling fluidized bed plant in previous research apply also for the boiler types analyzed in this work.
This research is a base for further investigation of fast pyrolysis integration into biomass CHP production. Future work should include analysis of potential economical benefits going along with findings stated in this thesis.