SUPERGEN Bioenergy Hub Extension

Lead Research Organisation: University of Manchester
Department Name: Mechanical Aerospace and Civil Eng

Abstract

Every year the UK produces millions of tonnes of waste which is landfilled. There are over over [ ]Mt waste wood alone produced in the UK each year. In addition there are large areas of land (e.g. disused landfill sites, coal-mines and water treatment facilities where energy crops could be grown to add remediation and improve land quality. It is well known that fast growing species such as willlow are efficient at sequestering heavy metals and other contaminants from the ground. When the crops are harvested the contamination is effectively transformed from a dispersed contamination on land to a much more concentrated form in the crop. Energy can then be extracted from the crop and the residues from the conversion process are easier to manage than the original dispersed contamination. However, care must be taken to ensure that the contaminated components are sequestered rather than being released to air, water or land in a way that could have negative environmental impacts.

This work will study existing and new plantations of energy crops to evaluate their utility in remediating land and the net environmental impact of this approach. We will also monitor the behavrour of the envrionmental contaminants in a range of different conversion processes to establish the pathway they take under different conditions. This is important for evaluating the environmental impact of the system but it also provides useful information for engineers charged with designing the conversoin plant, so that they know how to adjust process conditions, materials and predict any changes in performance associated with the waste fuel.

The focus of this work is energy crops grown on contaminated land. However, its application is much wider than that. The UK has a limited amount of land that can be used to provide renewable bioenergy. However, a vast quantity of wastes are produced that could sustainably deliver energy. In order to do this sustaianbly and effiiciently it is impmortant that engineers have access to data on how the contaminants in waste behave during conversion and this proejct will provide that, allowing more efficient design, lower environmental impact and supporting industrial deployment of these facilities.

Planned Impact

The hub acts as a focal point, bringing together the UK academic, industrial and policy communities to focus on the research challenges associated with delivering sustainable bioenergy systems. This is achieved partly with information sharing and joint events, but more importantly with tailored communications mechanisms to suit the information needs of different stakeholders. This allows the policy community to be expertly and effectively briefed on pertinent issues and to explain to researchers their information needs in tailored meetings timed and located to suit them.
Impact through industrial deployment is supported via close relationships on our advisory board with key stakeholders who can steer activities and readily access results. In addition there are dedicated technical sessions/meetings to ensure deep understanding of research outputs among the industrial community.
Provision has been made for researcher exchanges and these can be between academics and other academic institutes, industrial or policy partners. These will allow more in-depth insights and exchanges to be developed, facilitating knowledge transfer and tangible impact, with researchers specifically supporting policy issues or technical challenges.
 
Description Overall the project found that maintaining the crops on the selected sites at a viable level was challenging. It had been expected that there would be elevated levels of contamination (particularly heavy metals) in the resulting energy crops. However, conventional analysis did not provide a strong indication that this was the case.
Different pre-treatment options were considered and water washing was shown to be cheap and cost effective for most contaminants of interest.
The low level of contamination present in samples made it difficul to discrern any distinctive impacts on the elemental partitioning during conversion. However, with some conversion routes there were differences in conversion yield compared to what we woudl have expected with a virgin crop. The reasons for these are not yet fully understood.
The feedstock used for this work was the SRC willow grown on an old open-cast coal mine provided by Rothamsted Research.
- The fuel had low contamination and was comparable to willow grown on marginal land (with the exception of zinc levels which were higher) (data from the agronomy trial from Supergen Bioenergy II project)
- After water washing the willow, the ash decreases by 27%, major metals decrease by up to 44% and trace metals decrease by up to 30% with the exception of Co which decreases by 80%.
- The slagging and fouling tendency of the fuel decreases as the ash content and alkali and alkaline-earth metals decrease - i.e. pretreatment via water washing can improve the fuel properties for thermal conversion applications
- CO and particulate emissions from combustion are lower for the washed willow while the NOx emissions are higher.
- Pretreatment via water-washing increases the mobility of Zn and, hence during combustion, more zinc is retained in the bottom ash for the raw willow compared to the washed willow.
- Ex coal mine grown willow was used for this research. It was identified that potassium was the largest contaminant (2.8 wt. % dry bases) within willow. Potassium catalysed fast pyrolysis decreasing bio-oil organic content and increasing gas yields. The majority of the liquid produced from willow consisted of light volatiles due to the organic fraction being completely cracked. Roughly 99 wt. % of Potassium is entrained in the char, 1 wt. % of potassium entrained in the liquid product (can effect liquid stability).
- co-mingling contaminated and non-contaminated feedstock is beneficial in terms of resources, energy and GHGs; however financial and policy incentives differ for these feedstocks such that this isn't a potential option.
Exploitation Route The simple water washing system could (and is) being developed with commercial partners.
The slow uptake of contaminated species and low levels in the feedstock suggests this phytoremediation option is likely to be constrained to long term remediation needs only.
Further investigation of the conversion yield variation associated with some pathways could lead to insights for development of e.g. new catalysts for pyrolysis.
Sectors Energy,Environment

 
Description The work has led to a strengthening of the research team and facilities at Leeds University. Two PhD students are continuing in related areas: The first concerns pretreatment of conservation biomass and biomass from contaminated land; and the second concerns metal mobility during Miscanthus growth, particularly on contaminated soil. The research team have new facilities for pretreatment via water washing. There are plans to develop a follow on proposal in this area, but the work is, at present in too early a stage for further impact in industry.
 
Description Conference Presentation, McManus MC 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Third sector organisations
Results and Impact Conference Presentation: A techno-economic assessment of the gasification and conversion to bio-synthetic-natural-gas (BioSNG) of willow grown on contaminated land, Norman, J.B.& McManus, M.C. ISSST, June 2018, Buffalo, USA
Year(s) Of Engagement Activity 2018
 
Description Exhibition stand EUBCE (European Biomass Conference and Exhibition) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Exhibition stand EUBCE (European Biomass Conference and Exhibition)
Year(s) Of Engagement Activity 2018
 
Description Oral Presentation 12th ECCRIA Conference, Cardiff, 5-7 September 2018. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact An oral presentation at the 12th ECCRIA conference - D. Maxwell, B. Gudka, J. M. Jones, A. Williams, Pre-treatment of Short Rotation Coppice Willow for improved combustion stoves. 12th ECCRIA Conference, Cardiff, 5-7 September 2018.
Year(s) Of Engagement Activity 2018
 
Description Poster presentation 'Fast pyrolysis processing of Miscanthus x giganteus used in phytoremediation for production of fuels and chemicals' presented at Plants to Products Final Showcase (7th-8th November 2018)- Scott Banks 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster presentation at event
Year(s) Of Engagement Activity 2018
 
Description Presentation EUBCE, 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact presentation on biomass from contaminated land
Year(s) Of Engagement Activity 2018
 
Description Pyrolysis of biomass grown on contaminated land' presentation at SUPERGEN Researchers Day (2nd May 2018, Glasgow) delivered by Professor Tony Bridgwater 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Presentation at researchers meeting
Year(s) Of Engagement Activity 2018
 
Description Temporal emissions from forest bioenergy supply chains 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Oral presentation at EUPCE 2018, Kopenhagen
Year(s) Of Engagement Activity 2018