Operational impact to a CHP plant from integration of a biofuel top cycle pilot unit : A case study of KV62, Linköping

Sammanfattning: The coming years are expected to bring multiple challenges for all actors within the energy sector. For the Swedish utility company Tekniska verken AB, one of the upcoming tasks is to adapt their energy technologies to enable renewable, plannable and efficient heat and power production. At the same time as the share of renewable energy increases, the demand grows for technologies that can cover for the intermittency and align with policies and goals for sustainable energy. Part of Tekniska verken’s work is therefore focused on investigation of potential solutions for their heat and power production, that also agrees with the municipality’s vision to become “the World’s most resource efficient region”. One of the current projects within the area regards installation and tests of a of a biofueled top cycle (BTC) with high electric efficiency. The project is carried out together with the owner of the technology: Phoenix Biopower AB. This thesis is part of the pre-study to the pilot project, which is aimed to examine the feasibility of installing a pilot unit of the Phoenix Biopower BTC technology in Tekniska verken’s combined heat and power plant KV62, Linköping, Sweden. The thesis is meant to examine the site feasibility through evaluation of how the operation of KV62 will be influenced by the pilot unit’s operation. The work consists of a mapping of necessary interfaces between KV62 and the BTC pilot unit, followed by an assessment of the impact of the pilot unit on operation of KV62. The feasibility is evaluated with respect to operational limits of KV62 and the study includes both quantitative and qualitative evaluation of the impact from the interfaces between the two units. The study has special focus on the impact from the pilot´s flue gases on the flue gas handling system in KV62 which appeared to be a critical interface with respect to the operational limits. The resulting operational changes in this work indicate that the pilot unit can be installed and run in connection to KV62, but that normal operation of KV62 cannot be sustained during steady state operation of the BTC pilot. This is mainly due to the pilot unit’s load in terms of steam withdrawal, and additional heat to the heat recovery system, that cannot be fully managed with the current capacity for feedwater in KV62. However, there can still be potential solutions to run test campaigns of the BTC pilot simultaneously as KV62 delivers both heat and power. It should be taken into consideration that the pilot units’ behavior during transients are not investigated in this work and therefore need further investigation before a decision about the feasibility of the pilot unit installation can be made. Furthermore, some interfaces have multiple options for their placements, and therefore a detailed heat-and mass balance over KV62 would be suggested to investigate the effects of the symbiosis between the decided interface locations further.