Energy from waste:

Bioenergy

  • Conventional Renewable power generation – Fluidised Bed Biomass combustion

    Conventional Renewable power generation – Fluidised Bed Biomass combustion

    Supervisor: Supervisors: Dr Bill Nimmo and Prof Lin Ma

     

    To achieve the UK’s ambitious target of reducing greenhouse gas emissions by 80% by 2050 without compromising energy security, the UK’s conventional power plants must be operated in a flexible manner in terms of high efficiency, using alternative fuels (e.g. biomass) and integrating technologies for carbon abatement (e.g. Carbon Capture and Storage, CCS). Ultra-supercritical (USC) steam Rankine cycle power generation combined with Circulating Fluidised Bed (CFB) and Fluidized Bed (FB) combustion technology is the most viable alternative to the pulverised coal (PC)-based USC power generation. In addition, operating under USC/FB/CFB conditions has a number of advantages over USC/PC, particularly regarding fuel flexibility.

    However, there are still many fundamental research and technical challenges facing the development of this technology. In particular, combustion issues related to safe and stable operation of CFB/FB boilers when burning a variety of solid fuels are not yet fully understood and there is a great need to develop novel materials that will be able to cope with adverse conditions associated with operation.

    The specific project areas would include:

    To understand how the combustion of a variety of fuels affects Emissions, bed material agglomeration, fouling and corrosion of boiler heat exchanger tubes.

    Facilities at the University main campus and at the LCCC will be offered to suitably qualified students for study leading to a PhD in combinations of the following areas.

    1.       combustion testing at pilot scale  (250 kW Fluidised bed),

    2.       deposition testing and experimentation at pilot plant scale,

    3.       corrosion testing in lab scale furnaces,

    4.       fundamental TGA decomposition studies,

    5.       Biomass characterisation

    6.       Fluidised bed modelling and CFD studies

     

  • Conventional Renewable power generation – Fluidised Bed Biomass combustion

    Sustainable rural electrification in the developing world using microgrid integration of biogas and other renewable energy sources

    Supervisor: Professor Mohamed Pourkashanian, Dr George Konstantopoulos, Dr Christopher Jones, Dr Mark Walker, Professor Shibani Chaudhury,

    Recent studies estimate that close to two-thirds of the world’s population live in rural areas and around 1.3 Billion people, mainly living in South Asia and Sub-Saharan Africa, have little or no access to electricity.

    As an alternative to conventional large-scale electricity grid infrastructure is the use of off-grid integrated renewable energy systems (IRES) coupled with community scale microgrids, which can offer low-carbon electricity supply using locally available renewable resources.

    Biogas, produced though anaerobic digestion from local biomass resources which are abundant across much of the global south, can play a role in electrification whilst delivering additional benefits such as improved indoor air quality, public health and sanitation, reduced gender inequality and promotion of sustainable agriculture.

    This PhD project will investigate the design, operation, implementation and long-term community acceptance of rural electrification systems using biogas and other renewable technologies and will involve both modelling and field-based investigation.

    The project will involve an interdisciplinary approach and would seek to understand the interrelated criteria for successful IRES based energy projects. For example: (1) appropriateness of technology and optimised system scaling, (2) quantification of the electrical demand and its links to current and future behaviours, (3) understating criteria for community uptake and long-term acceptance of the technology and, (4) the provision of a dependable electrical supply by robust control of the microgrid and component energy systems.

    Objectives:

    • Investigation and assessment of renewable resource availability in Sub-Saharan Africa and South Asia, in areas where biogas based rural electrification projects could be feasible.
    • Development of electricity demand prediction tools based on community type, economic activity, population and wealth, including how demand changes over time e.g. based on changing attitudes or increased economic activity.
    • Optimisation of microgrid operation, component scaling and reduction in energy storage, using modelling tools, based on a variety of resource availability and electrical demand scenarios.
    • Design of advanced hierarchical control strategies for high quality electricity distribution across a variety of timescales.
    • Investigation of the key factors that promote acceptance or rejection of electrification in non-electrified communities
    • Through the existing international collaboration between the University of Sheffield and Visva Bharati in India, the work will benefit from access to a rural electrification site that is currently powering 45 households across two Indian villages. The student will be expected to travel to India in order to perform technical and social field studies on both this system as well as other non-electrified villages nearby.

    Funding notes

    This four-year studentship will be fully funded at Home/EU or international rates. Support for travel and consumables (RTSG) will also be made available at standard rate of £2,627 per annum, with an additional one-off allowance of £1,000 for a computer in the first year.  Students will receive an annual stipend of £17,336.

  • Conventional Renewable power generation – Fluidised Bed Biomass combustion

    Mitigation of ash deposition, slagging and fouling in biomass fired power generation

    Supervisor: Professor Mohamed Pourkashanian, Dr Kevin Hughes, Professor Lin Ma and Dr Janos Szuhanszki 

     

    Switching from fossil fuel fired power generation to the combustion of sustainably produced biomass can achieve near zero CO2 emissions, thereby significantly contributing to the decarbonisation of the energy sector. However, burning biomass in power plants designed for coal firing poses a number of challenges, including increased slagging and fouling and corrosion potential, which can reduce overall efficiency and plant availability.

    Making use of the state of the art 250 kW Combustion Test Facility at the Pilot Scale Advanced Capture Technology (PACT) Facilities, this project will involve a thorough and innovative experimental programme to characterise the above phenomena and correlate the findings with Computational Fluid Dynamics based modelling work as part of an integrated team.

    A central aim of the project is to identify successful mitigation strategies and thereby enhance the commercial viability of biomass fired power generation.

     

  • Conventional Renewable power generation – Fluidised Bed Biomass combustion

    Comparison of entrained metal aerosol emissions from the combustion of different biomass fuels

    Supervisor: Professor Mohamed Pourkashanian, Professor Lin Ma, Dr Kevin Hughes and Dr Karen N Finney

    Impurities in fuels have detrimental impacts on combustion/downstream systems, including CCS and heat recovery. Biomass with CCS can be a net negative emissions source, so is gaining interest, but as a result, there is more variation in the fuels being used, from conventional wood pellets to wastes, which have more impurities. This project will compare metal aerosol emissions from the combustion of such fuels throughout the combustion/capture plants, assessing the differences in the levels and species, monitored via ICP-OES at the UKCCSRC PACT Core Facilities. Quantitative data on the simultaneous multi-elemental detection for volatile/non-volatile species (major to ultra-trace elements) will focus on alkali (K, Na), transition (Fe, V, Zn) and heavy (Cd, Hg, Cr) metals, as well as acidic elements (S), as these are toxic, easily vaporised and/or cause operational issues. Combined with data for ash residue analysis (composition), mass balances will enable the determination of element partition/the fate of specific species, thus aiding in the development of better gas cleaning methods tailored for individual fuels and operation conditions.

     

  • Conventional Renewable power generation – Fluidised Bed Biomass combustion

    Integration of algal biofuel and biogas production

    Supervisor: Professor Mohamed Pourkashanian, Professor Derek Ingham, Professor Lin Ma and Dr Mark Walker

     

    There is an increased international interest in the use of algae to sustainably produce liquid biofuels to meet future energy demands. Anaerobic digestion/biogas production is an ideal synergistic process to the algal biofuel production and could help to satisfy the local parasitic energy demand of the biofuel production process, in a similar way to how it is currently used in wastewater treatment. The potential synergies include nutrient recycling, residue valorisation, biogas upgrading to biomethane and reduced water use. This project will develop knowledge into the combination of these two technologies using an integrated process modelling, built from sub-models describing the component physical, chemical and biochemical conversions and processes. The model will be used to perform system wide optimisation and scaling studies and eventually lead to recommendations on large scale installation of the technology.