Abstract
This research is aimed at improving low-grade industrial ovens (less than 250°C) in the manufacturing industry. Industrial ovens have a significant bearing on the environmental and economic impacts of a manufacturing factory due to their excessive fossil fuel consumption and influence on product quality. Therefore, this thesis’ research question is: 'How can manufacturers improve the environmental and economic performance of industrial ovens?' Research on industrial oven improvement is under-developed and there are significant improvement opportunities within many industrial-heating processes. Manufacturers traditionally prioritise economic assessment when evaluating capital investment projects and it is important that systematic engineering of industrial ovens align energy saving and process enhancement with key business interests. Furthermore, there is a need to incorporate stakeholder perspectives when improving oven processes. This thesis consists of three bodies of research, which all develop ways to improve the environmental and economic performance of industrial ovens: 1) Energy saving through process optimisation, 2) Process enhancement considering both energy consumption and product quality, 3) Developing sustainable industrial ovens. The key research outputs from this thesis are shown below: • There are two options to reduce energy consumption; to optimise the process by changing parameters, or to innovate the process by changing the way the heat is supplied to an oven. • System airflow can often be reduced by up to 30%. This was demonstrated at two factories and three oven systems, and has reduced gas energy consumption by 4,536,000 kWh and cut carbon emissions by 836 tCO2e per year. This has delivered a combined annual cost saving of £121,000. • Installing sufficient control capability enables heating processes to be optimised throughout their life, to meet changing requirements. • A novel approach of polymer cure characterisation has been developed that combines DMTA and a free phenol/CIE-Lch test. This demonstrated that temperature variation within a festoon oven results in dramatically different cure conversion (complete conversion time ranges from 73 to 40 minutes depending on location) and product quality. • A novel multi-criteria analysis method incorporating sustainability indicators from stakeholder’s perspectives has been developed for oven optimisation. • Retrofitting gas-fuelled processes with biomass technology is not economically viable. Alternative schemes that negate capital cost from the business would significantly enhance biomass viability. • Biomass technology is more viable in newly-built processes than retrofit scenarios. • EU Emission Trading Scheme (ETS) is an effective tool to encourage uptake of biomass heating technology in the manufacturing industry. This study demonstrates that there is opportunity to improve low-grade heating processes in the manufacturing industry. The environmental and economic performance of industrial ovens can, and should, be improved to help the manufacturing industry move towards a more sustainable future.