Real time control of gasifiers to increase tolerance to biomass variety and reduce emissions

The UK has enormous biomass resource which it currently underutilises, it is estimated that there is 10-14 million tons of sustainable biomass which could be used to generate electricity and heat pa. A recent report concluded that biomass can provide nearly 50% of the UK's energy needs by 2050, with the advantage that it is secure and provides power and energy on demand. Problems of utilising this is the accessibility of the biomass, the biomass variety and current processing options. Gasification is a process where biomass can be turned into its constituent components and produce hydrogen, carbon monoxide and methane, which can be used to drive a combustion engine or turbine to produce electricity, with heat being produced as part of the gasification process. Gasifiers are currently not meeting performance expectations primarily due to tar production (impacting syngas quality), biomass variability and lack of standards over pretreatment methods. This research seeks to overcome these technical and economic barriers by focussing on the energy requirements for biomass harvesting, developing better models of gasification processes for different biomass varieties and experimentally determining impacts of biomass variance and pretreatment options on gasifier performance. Importantly, instrumentation and control to minimise the tar formation and optimise the gasification process will be developed and coupled with techno-economic indicators of the systems. The research is composed of 7 interconnected work packages.

1) Develop mathematical models of the gasification process to predict the impact of biomass variety and its pretreatment on the gasification performance and allow optimal gasifier design.

2) Design a small, modular test-bed gasifier to allow development and testing of robust and inexpensive instrumentation and control strategies, to optimise the performance of the gasifer for different biomass and treatment options.

3) Develop gasifier instrumentation for 2) and for larger, fluidised bed gasifiers. Evaluate methods of real time tar detection that will provide a method to control the gasifier, by minimising the tar output and producing cleaner gas.

4) Assess the biomass characteristics of some indigenous UK species to allow selection and blending to reduce biomass variance, leading to improved gasification. Quantify the energy requirements for unlocking stranded forestry assets and the impact of various pretreatments on the feedstock potential.

5) Using the characterised biomass, the gasification efficacy will be measured for small and large gasifiers by assessing thermal, syngas and tar outputs. The impact of the control systems on performance will be evaluated.

6) The greenhouse gas emissions and sustainability of these processes will be determined using life cycle analysis and techno-economic investigations.

7) Using the available technical, environmental and economic data - from 1) to 6) - and strategies towards improved gasification process performance for biomass varieties and pretreatment will be identified for the UK and internationally. The potential of gaseous liquefaction and fuel storage will be identified.

This is a multidisciplinary project that focusses on the issues impacting poor, current gasification performance and will provide greater understanding of the role that biomass and its pretreatment has on gasification efficiency and emissions. Solutions will be researched to control the gasifier and reduce the tar formation and allow gasification of a broader selection of biomass. This will provide benefit to users around the world, allowing reduced tar formation, less downtime, and increased feedstock opportunities. This has significant socio-economic potential to impact sustainable energy and power production in the UK and around the world, with global population benefits of reduced greenhouse gas emissions from using sustainable biomass resources.

The direct beneficiaries will be the Project Partners; for academics, their high quality publications and for industrial partners, the potential to benefit commercially from the work and to secure their investment. There is a fine balance between open source access to the results and systems design, and commercial exploitation. This will be addressed at the first management meeting, with the ultimate aim to impact society and make gasification work for the world. The open source dissemination is attractive and recently exemplified by Tesla Motors releasing its patent portfolio to reduce the time to market for electric cars (Telegraph, 20th June, 2014), and still maintaining a commercial edge by benefiting from the market push from their newly engaged global developers. Gasification already has significant worldwide appeal, and end users stand to benefit from improved performance, being able to use different biomass types and controlling their systems to reduce tar formation, which will impact on the system's servicing requirements and reduce emissions by replacing fossil fuel with sustainable biomass feedstocks.

Integrating the knowledge, processes and technology from the project i.e. instrumentation, gasifier improvement, being able to process multiple biomass types and pretreatment optimisation, into societal benefit and impact is of paramount importance for the project. Societal benefits will be significant. Providing energy security for countries, and removing reliance away from fossil fuels, allowing countries to meet their CO2 reduction targets and opening up other opportunities for liquid fuel production, fertilizers and chemicals; significantly impacting farming and production capability. All of this, and it is sustainable. Within 15 years, these technologies and processes will have the potential to impact the quality of life of most people on the planet, providing electricity and thermal energy, for heating or cooling. Allowing the development of new technologies in remote areas, providing a level of comfort that only a fraction of the world currently enjoys, unsustainably and at the expense of high CO2 emissions. Even that can be eliminated, providing a world with less reliance on fossil fuels and impacting climate change.

The policy driven side of the research, linking with the modelling and experimental work, will provide strong evidence for the viability of biomass gasification, and a true measure of its likely impact on society. This will consider small and large scale gasifiers and UK and international perspectives. The contrast at present is the large "Drax" scenario, with biomass imported and government subsidies, compared with smaller, rural deployment of gasifiers in other parts of the world, that use locally sourced and sustainable biomass. The project considers the different scenarios, and will impact policy makers, allowing rational policy development based on the LCA and technological advance on biomass utilisation and gasification methodologies, with potential impact on the UK and global strategies for power and energy generation.

The potential to develop the systems and use know how from the research for commercial benefit to the UK, will result in fostering global collaborations with end users and increasing the UK's economic competitiveness by leading the research programme and commercialisation strategy, with significant aspirations for biomass and gasification. The problems are addressed at source, from the biomass to the gasifier to the output to economic assessment, providing significant understanding and market lead.

Organisations and commissions around the UK and world e.g. Forestry Commission, Biomass Energy Centre, Gasification Technologies Council, Underground Coal Gasification Association, Gasification Technologies Research Council of India will all benefit from this research providing a technical and economic framework for the future of biomass gasification.