Novel low energy plasma/catalytic gas cleaning process to deliver high quality syngas from the gasification of waste biomass

Lead Research Organisation: University of Leeds
Department Name: Chemical and Process Engineering

Abstract

The gasification of biomass wastes represents a major thermochemical route to produce a high energy value syngas from a source which is renewable and CO2-neutral. However, one of the major issues in the gasification process is contamination of the product syngas with tar. Tar is the key problem for biomass gasification and is a complex mixture of condensable hydrocarbons. The formation of tar causes major process and syngas end-use problems, including tar blockages, plugging and corrosion in downstream fuel lines, filters, engine nozzles and turbines.
This proposal seeks to develop a novel gas cleaning process based on low temperature plasma/catalytic technology to produce a clean, high quality syngas from the gasification of waste biomass. Gasification of the biomass will be investigated in an existing small-pilot scale fluidised bed gasifier, modified to include a downstream plasma/catalytic syngas cleaning process. Experimental and detailed analytical work developing the coupled biomass gasification-gas cleaning process will enable a mechanistic understanding of the tar reduction process and will be extended by CFD modelling of model tar compounds. Process modelling and simulation of the combined biomass gasification-plasma/catalytic gas clean-up sytem will build a foundation for process analysis, optimal design and operation to facilitate exploitation of this innovative technology development.

Planned Impact

[1] National Importance: The UK Department of Energy & Climate Change (DECC) Report "2050 Pathways Analysis" highlighted biomass as a key renewable feedstock to respond to the vital societal need for a step change in the sustainability of energy production required to combat climate change. Gasification of biomass represents a major sustainable route to produce syngas from a source which is renewable and CO2-neutral. Additionally, the recent "UK Bioenergy Strategy" (DECC, 2012) reported that the development of advanced conversion technologies, in particular reliable gasification and clean-up processing at scale, is crucial in allowing the UK to achieve the development of flexible bioenergy technologies.
The gasification of biomass wastes therefore has the potential to make a significant contribution to the future energy supply of the UK if the key problem of the high tar content of the product syngas can be overcome. Therefore, this proposal has the potential to impact at the National level by delivering a high CV syngas with ~zero-level tar content, thereby the gas becomes suitable for use in internal combustion engines and turbines for power generation thereby dramatically increasing the energy efficiency of the biomass gasification process.
[2] Impact on Industry: The UK gasification industry and bioenergy industries will also benefit from this research through our development of a gas clean-up system that can minimise tar formation in the product syngas so that it can then be used in higher efficiency gas engines, gas turbines and in the future fuel cells. The development of the technology would aid the gasification system manufacturers in marketing a higher efficiency system.
The application of plasma technology for tar removal from gasification syngas would provide a showcase for the development of plasma technology in the UK.
Catalyst companies would also benefit from the knowledge gained which would aid in the promotion and development of plasma treated catalysts.
[3] Training People: There is a recognized shortage of high quality scientists and engineers with energy-related training to support the UK's future energy research & development and innovation performance ("Jobs and Growth: Importance of Engineering Skills to the UK Economy; Royal Academy of Engineering, Final Report, September 2012). In addition, it has been estimated (NNFCC Briefing, "Bioenergy report on UK jobs in the Bioenergy sector by 2020" (2012)) that between 11,000-18,400 new jobs could be created in the Bioenergy power sector alone by 2020.
This proposal will impact on the training and career development of the Post-doctoral research fellows, but also through the involvement of PhD students and MSc project students associated with the research.

Publications

10 25 50
 
Description The integration of plasma and heterogeneous catalysis, known as plasma-catalysis, has great potential to generate a synergistic effect, which can lower the activation barrier of catalysts and activate catalysts at low temperatures. Further, the plasma improves the activity and stability of the catalysts, resulting in the remarkable enhancement of reactant conversion, selectivity and yield of target products, as well as the energy efficiency of the plasma-catalytic process. Compared with conventional thermal catalysis, one of the unique properties of plasma-catalysis is that plasma can be generated on the catalyst surface and in the pores of the materials, inducing strong interactions between the plasma and the catalyst. Highly reactive species (radicals, excited species and ions) and the electric field generated in the plasma interact with catalysts and positively affect the properties of the catalyst located in the plasma, e.g. reducing metal particle size and enhance metal dispersion on the catalyst surface. A novel biomass gasification- plasma-catalysis reactor has been built and has shown that downstream processing of the tars used a non-thermal plasma and plasma-catalysis system in the presence of steam to reduce tar content and increase syngas production. A range of process parameters were investigated. In the absence of plasma the pyrolysis-catalytic steam reforming of the tar produced a tar content in the syngas of 420 mg m-3.However, for non-catalytic plasma conditions, the tar content was reduced to 325 mg m-3 and for plasma-catalytic steam reforming, syngas tar content was markedly reduced to 150 mg m-3. There was also an increase in syngas and H2 yield due to steam reforming of the tar. Detailed analysis of the tars showed that they were largely composed of oxygenated hydrocarbons such as phenol, alkylated phenols, cresols and hydrocarbons such as benzene. The concentration of the individual hydrocarbon species were decreased in the presence of plasma and further decreased for the plasma-catalytic system. The effect of input power for the non-thermal plasma process (no catalyst) showed a marked decrease in tar content of the product gas, but the plasma-catalytic process showed that higher power input had a small effect on tar reduction. Increased steam flow rate for plasma-catalysis showed a decrease in tar content, but at higher steam inputs the effect was reversed due to water saturation of the system and reduced electron density. Plasma-catalysis was shown to produce lower catalyst coke deposition compared to non-plasma catalytic processing.
Exploitation Route The tar content of syngas from biomass gasification has been identified as the major drawback in the development of the technology. Gasification tars tend to be very unreactive, and are difficult to remove by thermal cracking, or physical processes. Due to its condensable nature, tar causes problems for downstream end-use process equipment such as gas turbines and engine systems. Such problems include blocking of gas fuel transfer lines, valves, fuel injector nozzles, etc Reduction of tar from syngas produced from the gasifictaion of biomass using a plasma-catalysis process could be important as a novel low temperature process to remove tar.
Sectors Energy,Environment

 
Title Steady state model for biomass gasification in fixed bed reactor - Mathew Aneke 
Description The steady state model for biomass gasification in fixed bed reactor was developed in Aspen Plus together with Fortran routines. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact N/A 
 
Title Steady state model for biomass pyrolysis only - Mathew Aneke 
Description The steady state model for biomass pyrolysis only was developed in Excel. The model is used to select different biomass with the aim to obtain higher project yields such as H2, CH4 and CO, and lower tar. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact N/A 
 
Description A talk or presentation - Research Seminar at Changzhou University, China - Prof Wang 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I was invited by the President of ChangZhou University - Prof Q. Chen to have an academic visit to ChangZhou University. I was invited to give a Research Seminar on what Process/Energy Systems Engineering can do for Power Plants, Carbon Capture and Utilisation, Bio-Energy & Energy Storage. Lots of questions raised by the audiences (academics & MSc Research students).
Year(s) Of Engagement Activity 2017
URL http://uni.cczu.edu.cn/2017/1215/c8420a173493/page.htm
 
Description Prof Wang - Heriot Watt University - Jan. 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact Under the invitation of Prof Mercedes Maroto-Valer, Prof Wang gave a lunch time one hour Seminar on CCS and its recent development.
This has inspired lots of discussions and potential future collaboration on how to intensify the solid adsorbent process for Carbon Capture.
Year(s) Of Engagement Activity 2016
 
Description Prof Wang - University of Sheffield - Research Seminar - Feb. 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact Under the invitation of Prof Peter Styring, Prof Wang was invited to give a lunch time seminar in the Department of Chemical Engineering, University of Sheffield. The audience were from the Chemical Engineering Department and Energy2050 (mostly PhD researchers).

The Seminar should be very helpful in inspiring the research interest of the audiences.
Year(s) Of Engagement Activity 2016
 
Description Prof Wang - University of South Africa - Invited Talk - Dec. 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact In Dec. 2015, Prof Wang was invited to visit University of South Africa at Johannesburg, South Africa.

A Seminar was organised under the invitation of Prof LIU on CCS.

This EPSRC funded project was the main topic of the Seminar. The audiences has strong interest to know this.
Year(s) Of Engagement Activity 2015
 
Description Prof Williams - Glasgow Biomass Gasficiation Workshop - Presentation on plasma-catalytic cleaning of atr from biomass gasification syngas 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Glasgow University Biomass Gasification Workshop
Year(s) Of Engagement Activity 2015
 
Description University of Leeds Be Curious Science and Engineering Public Open Day - Public Engagement; Prof Paul Williams, Dr Anas Nahil 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The 2017 Leeds Science Festival UK in March, featured the 'Be Curious 2017' event at the University of Leeds and attracted great interest from the public with interactive displays and presentations of research and innovation. The theme of this year's event was to highlight the benefits of research and innovation for the Leeds City area and Yorkshire. Large crowds attended the event with exhibits from all departments within the University showcasing; improving lives in Yorkshire through science and engineering; how culture enriches lives in Leeds and Yorkshire; how climate change and water research benefits Leeds and Yorkshire; Leeds as a sustainable city; towards a healthier Yorkshire

The festival featured the Plasma-Catalysis process as a distinct exhibit. Specific funding from the project purchased large scale plasma-balls to attract the public and make the project more attractive to the public,
Year(s) Of Engagement Activity 2017
 
Description University school visit-Hull University 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A group of school students visited the University of Hull in March 2017 where Dr Chunfei Wu explained the energy from biomass by gasification project.
Year(s) Of Engagement Activity 2017