Thermal plasmas for industrial high-temperature processes: Modelling studies of aluminium smelting and steam cracking
Typ
Examensarbete för masterexamen
Program
Publicerad
2022
Författare
Dahiya, Abhishek
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Industrial emissions constitute approximately 30% of total greenhouse gas emissions in 2019. Several industrial sectors have taken steps to replace their energy sources with renewables such are solar and wind power. However, many industrial processes require high temperatures which have traditionally been achieved by combustion of fossil fuels. It has proved challenging to develop alternative processes to reduce carbon dioxide emissions from these processes. One such process is secondary aluminium smelting, and as much as one-third of all aluminium produced globally comes from scrap products. An important part of the recycling process is melting and alloying with current state of the art furnaces being equipped with oxy-fuel burners. Partial or complete electrification of this process could cut emissions and reduce dependence on fossil supply and prices. Though, the high temperature and melt rates, fundamental to the process, are not achievable through Direct Electric Heating.
A potential alternative for high temperature processes is to switch fossil fuel burners with electrically generated thermal plasma using plasma torches. This study presents a comparison of oxy-propane and CO2-based plasma burners in the aluminium smelting process. Real process data as delivered by an industrial partner is used to establish a reference case. With process parameters kept constant, the radiative heat load from a plasma torch is modelled in a first step. Process conditions, energy costs and emissions from using a plasma torch in the process is evaluated and compared to the reference case with oxy-fired technology. It was found that the energy costs are 39.1% higher and an increase in melting time by 14%. Although, along with reduced dependence on gas, process modification leads to 94.7% cut in carbon emissions from primary energy. Additionally, this master thesis also includes a brief study of the expected effects from exchanging the burners for plasma torches in a steam cracker.
Beskrivning
Ämne/nyckelord
Thermal plasma technology , Aluminium Recycling; , Radiative Heat transfer