BECCS integrated sustainable treatment of seaweed

Traditional thermal processing of wet biomass (typical seaweed has 85% moisture) is not efficient as a lot of energy and space is spent on drying the feedstock. Transportation and associated handling costs are also high. The proposal aims to develop an advanced treatment technology with high efficiency, no need to dry the feedstock, compact design, and produce net zero or even negative CO2 emissions. The whole system acts as a distributed energy supplier, producing heat and electricity, as well as high purity clean water for onsite and vicinal usage.

This solution is intended to propose a comprehensive and sustainable route to treat seaweed, in terms of self-sustained energy supply, clean water recycling and CO2 capture, recycling and utilization. Biomass wastes such as seaweed are treated on-site applying a unique and advanced technology, namely supercritical water oxidation (SCWO) or gasification (SCWG). The gas stream produced from this technology contains the energy converted from the biomass waste and is then treated in a micro-sized combined heat and power (mCHP) device or fuel cell to provide the heat and electricity required to operate the system. The final flue gas contains high concentration of CO2 and pure water where CO2 can be recycled for use in glasshouse while the clean water can also be recycled for on-site usage.

The proposal aims to use commercial process simulation tools to evaluate the performance of the whole system considering several combination scenarios of SCWO/SCWG, m-CHP/FullCell and CO2 utilization options. Techno-economic analysis including mass and energy balance of the system, as well as the CCUS costs and CO2 savings will be thoroughly investigated. The essential data from this feasibility study will be produced based on the specific user case and will be further explored to attract more research and investment interest.

An unfortunate disadvantage of biogas from digester today is that the systems used in the production of biogas are not efficient. Although the biogas plants available today are able to meet some energy needs, many governments are not willing to invest in the sector. Traditional thermal processing of wet biomass (typical seaweed has 85% moisture) is not efficient as a lot of energy and space is spent on drying the feedstock. SCWO(G) is a much higher efficient process in that water itself is reactant without the necessity of energy-intensive drying process. SCWO is a destructive treatment (>99% destruction efficiencies) where the compounds treated are mineralized to simple elements or harmless molecules (e.g., water and carbon dioxide) therefore there are no pollutants such as NOx, SO2 and particulate matters. SCWO is an extremely rapid and effective reaction (typical reaction times are in the order of 5-10 seconds) making it possible to build systems that are very compact and have a high throughput.

Micro-gas turbines (MGT) offer several potential advantages compared to other technologies for small-scale power generation, including: a small number of moving parts, compact size, lightweight, greater efficiency, lower emissions, lower electricity costs, and opportunities to utilize waste fuels. mCHP applying MGT provides an emerging and promising solution for distributed energy and power system.

The combination of SCWO(G) and mCHP using MGT produces high concentration of CO2 which makes the CCUS process much cost effective. The CO2 produced from this process can be used for algae cultivation and raw material for producing fish food. The whole process can be energy sustained and does not produce any net CO2 emissions. This is the first-of-its-kind highly efficient waste-to-energy, and negative CO2 emission solution (BECCS) for the marine based biomass applications.

The proposer's capability in conducting this multi-disciplinary solution has been evidenced by previous involvement and high quality publications associated with four relevant major UK EPSRC projects on Supercritical power plants (EP/M01536X/1), Biomass gasification (EP/F038070/1), Natural gas-fired power plants CCS (EP/J020745/1) and Coal-fired power plant CCS (EP/G063176/1).

The solution contributes to the development of transformative, environmentally and economically viable approaches and interventions by proposing a disruptive and novel integrated system. It has great potential in leading to demonstrable substantive improvement with significant measurable benefits. The conceptual design, once its feasibility approved in terms of sustainability in heat and electricity requirement, waste heat recovery, waste water recovery and CO2 product gas recycling, will explore a valuable route to market and an innovative negative CO2 emission technology, especially in the sustainable treatment of marine based biomass such as seaweed.

Wider impacts:

Zero/Negative CO2 emission in proposed controlled solution;

Furthering of academic knowledge, investment into the training of the next generation of academic and industrial researchers;

Increase the competitiveness of marine industry in sea biomass management.

The University of Hertfordshire (UH) is the UK's leading business-facing university and an exemplar in the sector. It is innovative and enterprising and challenges individuals and organisations to excel. UH is a modern university based largely in Hatfield, in the county of Hertfordshire, about 35km north of London. Described as “the UK’s leading business-facing university”, UH has more than 25,000 students enrolled from nearly 90 different countries. UH won the Guardian University Award for Student Experience in 2015, while 95.2% of University students are in work or further study six months after graduating. The University has many close links with industry, and every British Formula One team has at least one UH graduate. Degrees in healthcare science and the pioneering paramedic science BSc make UH a preferred provider for the NHS in the east of England and the Universities Careers and Placements Service offers graduates lifelong support on employment and career development.

Dr Wenbin Zhang: Dr Wenbin Zhang is currently a Senior Lecturer in School of Engineering and Computer Science in University of Hertfordshire. He obtained both Bachelor and PhD of Engineering from State Key Lab of Coal Clean Combustion technology (SKLCCC), Dept. of Thermal Engineering, Tsinghua University in China. He had been working as a Research Fellow in Tokyo University of Agriculture and Technology, University of Birmingham, University of Nottingham and University of Warwick. He is an invited reviewer for around 10 international scientific journals and EPSRC/Horizon Europe fund applications, and also an editorial board member of International Journal of Energy and Power Engineering, Energies and IntechOpen Publishing. He is a Fellow of Higher Education Academy of UK. He holds academic memberships of World Society of Sustainable Energy Technologies (WSSET), and UK Carbon Capture and Storage Research Centre (UKCCSRC). He has been actively involved in 6 large EPSRC projects on carbon capture, biomass gasification and heat pumps. His main research areas are: Carbon capture using solid sorbents and fluidized bed technology; BECCS (Bio-energy with Carbon Capture and Storage), Direct Air Capture; Process simulation of power plant and industrial systems integrated with thermal energy storage and carbon capture; Efficient energy systems such as CHP and heat pump/engine; Gasification, carbonization, pyrolysis and combustion of biomass materials and wastes.