Posters

 We have three dedicated poster sessions during the conference.  Poster presenters have been asked to prepare a 3/4 minute presentation of their poster, participants will be guided through the poster session by a session chair.

More information can be found in your conference booklet.

 

Poster board

Title of poster

Presenter and Institution

1

Techno-economic analysis of biomass gasification CHP system

The purpose of this techno-economic analysis is to compare and evaluate a set of biomass gasification CHP (combined heat and power) systems selected for the economic feasibility, energy efficiency and near-term technical viability. In this study, a techno-economic comparison is performed considering two gasification processes (downdraft and circulating fluidised bed gasifier) for electricity and heat cogeneration from lignocellulosic biomass (Miscanthus). These systems consist of major process steps such as biomass cultivation; biomass processing; gasification; syngas cleaning and electricity generation. A comprehensive model of the power plant is developed employing mass and energy balance analysis. A heat integration analysis is also carried out using pinch analysis, resulting in an energy-sufficient process with no requirement for external hot utilities and net power production. The economic assessment is analysed in terms of the Net Present Value (NPV), internal rate of return (IRR) and Return of Investment (ROI) to evaluate the feasibility of different biomass gasification CHP systems and scale of operation. 

Dr Chen-Wei Chang

The University of Manchester

2

Plasma gas cleaning process for the removal of model tar compound from biomass gasification

Gasification of biomass wastes represents a major sustainable route to produce syngas (H2 and CO) from a source which is renewable and CO2-neutral. However, one of the major challenges in the gasification process is the contamination of the product syngas with tar, particulate matter and other pollutants. 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. These problems have resulted in high operational costs and even plant shut-down. Non-thermal plasma technology provides an attractive alternative to the conventional catalytic route for converting tar at low temperatures. In non-thermal plasmas, the overall gas temperature remains low, while the electrons are highly energetic, which is sufficient to break down most chemical bonds of molecules and produce highly reactive species: free radicals, excited atoms, ions and molecules for chemical reactions.
 
In this work, an AC gliding arc plasma gas cleaning system has been developed for the removal of tars from biomass gasification. Toluene has been chosen as a model tar compound since it represents a major stable aromatic product in the tars formed in high temperature biomass gasification processes. The effect of different processing parameters (e.g. steam-to-carbon (S/C) molar ratio, toluene feed rate and specific energy input (SEI)) on the reaction performance (e.g. toluene conversion, yield of products and energy efficiency) has been investigated. Optical emission spectroscopy (OES) has been used to understand the role of steam on the formation of reactive species (e.g. CH, CN, NH and OH) in the plasma chemical reactions. In addition, the possible reaction mechanisms and pathways involved in the plasma conversion of toluene have been discussed by combined means of OES and the analysis of gas and liquid products.

Dr Chunfei Wu

University of Hull

3

Effects of oxidants on model tar destruction in a rotating gliding arc discharge reactor

Gasification is regarded as one of the most promising and sustainable technologies to convert biomass into syngas (a mixture of H2 and CO) which can be used for power generation or synthesis of a wide range of fuels and chemicals. However, biomass gasification process generates undesirable heavy hydrocarbons (normally referred as “tar”) which causes fouling, blocking and corrosion problems in downstream equipment and limits the use of syngas for energy applications. In this study, the destruction of toluene as a tar surrogate, was performed in a rotating gliding arc (RGA) plasma reactor. The effects of water vapor and carbon dioxide, two major oxidants existing in the gasification products, on the destruction efficiency of toluene were studied. The addition of CO2 was found to slightly suppress the toluene destruction. Increasing the input CO2 concentration decreased the destruction of toluene from 73.9% to 64.3%. However, adding proper amount of water vapor had a positive influence on the removal of toluene. With the increase in the water vapor concentration, the toluene destruction gradually increased and reached a maximum of 85.2% at a steam concentration of 16%, and then decreased when further increasing the steam content. The major gaseous products in the plasma process were H2 and CO. The carbon precipitation was well solved when adding CO2 or H2O to the process. In addition, optical emission spectroscopy (OES) was used to characterise the RGA plasma. A variety of reactive species formed in the plasma process was observed, providing new insights into the possible reaction mechanisms and pathways of the plasma process.

4

Gasification of Torrefied Woody Biomass with Carbon Dioxide in a Fluidised Bed

Torrefaction of woody biomass at mild pyrolysis temperature is usually applied to improve the fuel quality of biomass. However, removal of a large amount of volatiles after torrefaction, torrefied biomass gasification with air cannot enhance the syngas production. Therefore, applying the Boudouard reaction, gasification of torrefied biomass with CO2 at higher temperature could improve the syngas quality. In this study, gasification of torrefied woody biomass with CO2 was carried out in a 30 kWth bubbling fluidized bed gasifier to investigate the effects of the air equivalence ratios (ER) and gasification temperatures on the syngas components, the higher heating value (HHV) and tar content. The preliminary results show that the syngas content of CO2 increased with increasing the ER, but that of H2, CO, CH4 shows the contrary results. In addition, at higher temperature above 800 C, gasification with CO2 can enhance CO concentration compared with the air-blown gasification process, due to the Boudouard reaction on the higher carbon content of torrefied biomass. Moreover, the tar content clearly decreases with increasing of ER. Increase in the ER enhances oxidation reaction, reduces the tar formation, and reduces the quality of syngas. The gasification of torrefied woody biomass produced the lower tar content compared with that of the raw biomass because of the lower in O/C and H/C ratio in the torrefied woody biomass consuming more oxidation reaction. The tar contents from CO2 gasification are only half compared to that from air-blown gasification. Also, the lower heating value of syngas is increased about 30% from CO2 gasification compared to that from air-blown gasification.

Dr Keng-Tung Wu

National Chung Hsing University

5

Hydrodynamic behaviour of Novel Interconnected Fluidised Beds for Biomass Gasification

The inter-connected fluidized bed (IFB) cold model with four 10 cm x 10 cm compartments was built to establish operational parameters and provide the information for future commercial design of an IFB gasification system. Glass beads, dolomite and limestone were employed as bed materials to investigate the effects of those materials. The effects of the particle weight, gas velocity, orifice diameter, and orifice height on the circulation rate of solids (CRS) in the IFB were investigated. The preliminary results show that the CRS increases with increasing gas velocity of the lean bed, bed weight and orifice diameter. The diameter of limestone decreases during the operation and the value changes from 0.2483 mm in the beginning to the 0.1799 mm after 30 minutes. The diameter of dolomite keeps near constant value of 0.18 mm during the operation. It shows that dolomite is better than limestone if the CO2 capture sorbent is require to cycle use. The hot model will be designed and commissioned based on the present results to carry out the further investigation.

6

Development of a throated downdraft gasifier test-bed for evaluating gasifier control systems

The primary objective of this study is to develop a downdraft gasifier test-bed to evaluate gasification of various biomass feedstocks, tar detection systems and gasifier control strategies. The development process consisted of optimising the gasifier dimensions through empirical relationships, the physical properties of the biomass and experimental data in the literature. The two most important dimensions to evaluate were the throat diameter, the smallest dimension in the gasifier, and the diameter of gasifier. Other important design parameters were the hearth load and gasification rate used for eventuating the gasifer throat and overall diameter. An optimum Equivalence Ratio (ER) of 0.3 was considered to evaluate the total air required for the gasification process, considering the physical properties of local Miscanthus pellets and gasification reactions. Once the throat diameter and gasifer diameter were evaluated, the reactor height was evaluated based on the total volume occupied by the Miscanthus with the mass flow rates used for initial gasifier dimensions. Furthermore, the nozzle size and number of nozzles was evaluated with respect to the throat size. A 3-D design model was carried out in SolidWorks 2014. The design and fabrication strategy of the gasifer was to enable a flexible system to allow rapid changes of the design elements, allowing optimization for different feedstocks. The upper part comprised a straight cylinder and the throat geometry. The lower part, connected via a flange assembly, contained the ash grate. Different mesh sizes for the grate can be used to investigate its effect on gas quality.

Dr Zakir Khan

University of Glasgow

7

Flame photometry as tar detection system for biomass gasification

Tar produced during gasification limits the end use of syngas and may damage expensive downstream equipment, such as internal combustion engines (ICE) or gas turbines. Consequently, identifying and developing novel methods of measuring tar in biomass gasification has recently attracted greater attention with the objective to optimize online tar detection systems. This study provides the initial development of a flame photometry system, that is a rapid, non-intrusive technique.  The process is based on identifying the emitted spectrum from a syngas combusted flame allowing information on the tar components to be determined from the flame colour.  The cost of implementing spectroscopy systems is broadly determined by the necessary resolution.  In practice, the system should be sufficiently sensitive to detect the presence of tars, but not necessarily the tar components.  The data from the flame photometer can be used to provide real time feedback control of the gasifier to reduce the tar in the syngas, allowing operation of the system on the minimum tar production point.  
 
The work presented investigates and experimentally demonstrates various system designs.  The broad, visible emission spectrum from idealised tar compounds produced from a pyrolysis processes and the variation in the flame’s irradiance upon combustion of various amounts of tar will be presented. The experimental method was approached with a mind-set to develop cost-effective and robust flame colour tar detection systems. Within the scope of this work, it can be concluded that pyrolysis of pine wood saw dust feedstock, produces tar containing oils which upon combustion produces a spectral emission that peaks at 589 nm in the visible spectrum and at 766 nm in the near-infrared spectrum. With the use of simple photo-electric equipment a correlation between tar concentrations and flame emission intensity was observed allowing feedback control for gasifier systems. 

8

Physical and flowability characteristics of Miscanthus pellets

The use of Miscanthus grass as a biomass source has increased within recent years due to its high yield per hectare and suitability as an energy feedstock. This work presents the physical characteristics and flowability of different types of Miscanthus in a downdraft gasifier developed as a test bed for developing robust gasification of different feedstocks, tar detection systems and gasifier control strategies. This work was carried out to select the ideal Miscanthus with optimal flowability characteristic through a lab scale throated type downdraft gasifier. Five genotypes were provided by Terravesta, four of these were bred at IBERS, University of Aberystwyth. These samples are different from each other in growth habits, stem density, height, maturation time and harvest moisture content. Various physical characteristics of the pellets were measured including: pellet density, bulk density, flowability, Hausner ratio, bridging, angle of repose, durability and hardness of the pellets. In addition, the energy content was found from measurement of the higher heating values. All of the varieties of Miscanthus had Haunser ratios below 1.  Excellent flowability was observed with an average angle of repose of 29°. It was further found that the 6 mm pellet size with low moisture content resulted in the low angle of repose (26°). The bridging analysis in throated type downdraft gasifier inferred that the 6 mm pellets (18 mm length) suffered bridging whereas 5 mm (17 mm length) produced a smooth flow through the gasifier throat.  Efforts to establish the flow rate at which bridging occurred in the gasifier for each pellet size were made. A statistical comparison of the heating values found that there was no significant difference between the genotypes.

9

CFD study of a circulating fluidised bed (CFB) reactor for gasification of miscanthus

Gasification seems a rigid technology, because it requires a thorough adaptation of the biomass feedstock to be gasified. Once the design of gasifier is chosen, it allows little operating flexibility. This means that tiny variations on biomass properties may lead to undesirable consequences, such as operating instability, loss of performance, problems of scaling, etc. The objective of this study is to explore the link between the feedstock’s characteristics and the design of a gasifier using CFD numerical technique. This will allow to select the proper feedstock for an existing gasifier and/or to define the gasifier’s design for a feedstock with specific properties. Miscanthus has been selected as feedstock as it is a sustainable and reliable biomass energy crop, and also due to its availability as it is widely cultivated across Europe. Circulating fluidised bed gasifiers (CFBG) have been commonly used in the industry due to their capacity to attain high reaction rates and thermal efficiency. This particular reactor design allows to achieve relatively uniform bed temperatures due to the high gas-solid interactions resulting from the high air velocities required for biomass gasification. In this research, a CFD model using an Eulerian-Eulerian approach was developed to simulate the original design of an existing 12kg h-1 CFB gasifier. The initial validation of the model was carried out by comparing predicted results with data measured experimentally. The combination of experimental and modelling tools, perfectly complement each other as they allow to play with diverse process parameters and therefore to get a wider range of data. The model was also used to study the variation of the gas composition and quality at different operational conditions during gasification of miscanthus. Furthermore the effects of varying the geometry and original design of the gasifier over the gasification yield, were also examined. 

Dr Xi Yu

Aston University

11

Characterisation of products from co-gasification of Nigerian biomass in a pilot scale down draft gasifier

The use of biomass for thermal conversion systems (alternative to fossil fuel) leads to increase in ash generation of up to 40 % of the biomass (depending on type and form of biomass) from thermal conversion systems. The disposal of ash poses different challenges including heavy metals components of the ash, while land filling is being discouraged for any types of waste products. Agricultural use of ash provides a sustainable option; therefore it is important to prioritise biomass residue qualitatively and quantitatively. This is important to ensure the ash generated through these processes is of beneficial and no harm to both the soil and crop, and generally the ecosystems. In terms of process practical operation point of view, it is important to avoid the formation of fused or partly-fused agglomerates and slag deposits.
Co-gasification studies were carried out in a 25 kWth pilot scale down draft gasifier. The gasifier was operated over a temperature range of 750–900°C whilst varying air/fuel ratio. Three types of Nigerian biomass generated from oil processing units were studied: empty fruit bunch (EFB), mesocarp fibre (MF) and palm kernel shell (PKS). The gas compositions, gas yields, quality of liquid and solid products were determined and correlated with temperature, and types of biomass used. Online FTIR gas analyser was used for the analysis of the gaseous elements. A detailed analysis on tar sampling (tar probe developed based on BSI DD CEB/TS 15439:2006) and quantification are examined in this paper. The study showed that mixing the biomass affects residues yield from the downdraft gasifier plant, and consequently the performance of flue gas cleaning equipment, fouling of gasifier surface, and the handling and the utilisation/disposal of ash. This is particularly true for PKS, which increased the rate of sintering significantly when co-fired with other biomass.

Mr Kelechi Anyaoha

Cranfield University

12

On the production of Valuable Products in the Pyrolysis of Cellulose: Influence of Catalyst Acidity and Reaction Conditions

Biomass is regarded as one of the only sustainable sources of organic carbon and is increasingly being investigated as a replacement for fossil fuels.1  The thermochemical conversion of biomass through pyrolysis presents a unique opportunity to convert waste biomass into high value added compounds such as furans and aromatics. The liquid product produced through non-catalytic pyrolysis, although has several potential uses as a liquid fuel, is often unstable and highly corrosive and requires additional upgrading to improve its quality. The introduction of a catalyst in the pyrolysis may relieve the need for a secondary upgrading step, instead, integrating the catalyst into the pyrolysis process, where the complex reaction mechanisms can be directed towards the production of more desirable products.2 Cellulose is the main component of lignocellulosic biomass; the product distribution of cellulose catalytic pyrolysis depends heavily on the reaction conditions and the physicochemical properties of the catalytic material. Our initial investigations using Py-GC/MS into cellulose pyrolysis, over a range of conditions, with a variety of acidic catalysts has shown how the reaction pathway of cellulose degradation can be tuned to promote the formation of either furans or aromatics. Well established catalytic materials that are already employed in commercial operations, such as Silicoaluminophosphates (SAPO’s), Zeolites (ZSM-5, Y-Zeolite) and mineral clays (K10), were tested in this study showing interesting trends of their product distribution. Their physicochemical properties were evaluated by means of ICP-AES, N2 Porosimetry, Pyridine adsorption and XRD; allowing correlations to be established. 

 
References:
1 R. a Sheldon, Green Chem., 2014, 16, 950–963.
2 A. V. Bridgwater, Appl. Catal. A Gen., 1994, 116, 5–47.

Mr Joseph Socci

Aston University

13

Is BECCS an option in Colombia? - A biomass resource and technology assessment for local agricultural residues

In many developing countries with predominantly agricultural-based economies, crop-residues represent a large potential as a biomass resource for energy generation. This is the case of Colombia, which theoretical biomass energy potential from these residues is estimated at about 400 PJ/year. This potential remains mostly untapped and in some cases is converted on traditional inefficient processes for cooking or heating purposes. Numerous rural areas where the crop residues are available demand large amounts of electricity and heat, mainly for farming and households activities, which could be supplied using bioenergy. Although extended research has been conducted worldwide in this direction, previous studies cannot always be applied straightforward to some specific countries. Consequently this work explores the biomass resource potential of agricultural residues in Colombia and the feasibility of using gasification technology by studying the influence that process and external parameters have on the syngas composition, heating value and process conversion efficiency of the system.

Mrs Samira Garcia

University of Manchester

14

Catalytic fast pyrolysis processing of beech wood with Ce-ZSM-5 and V-ZSM-5 catalysts

 

 

Dr Daniel Nowakowski

Aston

15

How effective is biodiesel waste glycerol as a feedstock for methanation?

Crude glycerol (glycerin) has become a waste product of the biodiesel industry. Surplus glycerol from biodiesel production has caused glycerol prices to plummet and refiners are paying more than the value of glycerol in transport and disposal costs. A proposed solution to increase the sustainability of the biodiesel industry and reduce the cost of biodiesel production, is to gasify glycerol to produce methane rich gas (substitute natural gas or SNG).
 
The potential of a low temperature steam reforming (LT-SR) route is outlined in this project. The SNG produced has the potential to support in situ heat and power demands of the biodiesel refinery through gas combustion, or economically through feed in tariffs or grid exportation. Projections on the quantity of methane that can be produced from glycerol have been made based on glycerol capacity in the UK and the world.
 
A key factor for success is avoiding the high processing temperatures.  This requires a catalyst which promotes steam reforming and methanation reactions at low temperatures, and is resistant to carbon formation. Ideally, the catalyst will avoid the water gas shift and promote the direct methanation reaction (autothermal). 
 
Experimental modelling of the LT-SR has been carried out using Aspen Plus. The potential to recycle the heat released from the exothermic reaction is a key step in ensuring a low energy LT-SR. Furthermore, flow rates provide an expected output from a reactor and a baseline for future catalyst testing and novel catalyst creation.

Mr Robert White

University of Leeds

16

Deploying Photocatalytic Technology for the Conversion of Cellulose II to High Value Products

Conversion of waste cellulosic biomass into liquid fuel provides a sustainable alternative for fossil fuel. Despite the advancement made in this field, direct low energy conversion of cellulose into fuel remains a significant challenge due to its water insolubility and rigid nature. Here we present the photocatalytic conversion of waste biomass into value added platform chemicals utilising α-cellulose as a model feedstock. A widely known catalyst; TiO2-P25 nanoparticles immobilised into ball milled α-cellulose were UV-irradiated with four low-power 36 W UV-A compact non-integrated fluorescent lamps housed in a bespoke light unit. Quadrupole time of flight mass spectroscopy analysis revealed the formation of multiple cellodextrins including glucose cellobiose as well as an array of C5 oligomers derived from photocatalysis of α-cellulose. Production of ethanol; a sustainable alternative liquid fuel was demonstrated using the yeast strains Saccharomyces cerevisiae and Candida wickerhamii fermenting cellulose degradation products as substrates. Catalysts applied here are of low cost, recoverable and can be activated by harvested natural light or augmented low power light emitting diodes (LEDs). Further studies are carried out to construct a test reactor composed of LEDs for photocatalysis as well as an in housed membrane separation system for efficient harvesting of fermentable sugars for ethanol production. 

Dr Nathan Skillen

Queens Belfast

17

MISCOMAR. Miscanthus biomass options for contaminated and marginal land: quality, quantity and soil interactions

Bioenergy production exists at the interface of policies on agriculture/land use and energy generation. To avoid tension between food and fuel production, energy crops would ideally be grown on medium or low quality agricultural land wherever possible. Therefore, the focus of this new project, MISCOMAR, is biomass production from marginal land in Europe. Progress will be made by improved understanding of the range of land suitability for Miscanthus cultivation. The currently understood range will be extended to consider heavy metal contaminated land in Poland, increased production from agriculturally marginal land in Germany and Wales along with ecological and environmental improvement of depleted, intensive arable land in Eastern England. 

The project will compare crop performance at these sites between novel, stress tolerant, seed-based Miscanthus genotypes and agronomy with the standard commercial clone M. x giganteus. It will consider both the impact of a range of soil limitations on the plants themselves as well as the potential for the crop to improve the health of these soils during the production cycle. Following harvest, the resulting biomass will be tested to determine its suitability for energy conversion through anaerobic digestion. For the Polish sites particularly, heavy metal uptake to the biomass will be studied to determine any potential for remediation of these contaminated soils. Soil carbon content, organic matter build up and nutrient balances will be considered at all sites. 
 
Outcomes will be disseminated as widely as possible to offer farmers, land managers and policy makers increased opportunities and options for environmentally sustainable biomass production on otherwise economically marginal agricultural land. In the final workpackage of the project, concepts for the integration of Miscanthus into existing landscapes, crop rotations and farming systems will be developed based on data and information generated during the MISCOMAR project coupled to insights from farmer surveys. 

Dr Jon McCalmont

IBERS

18

LowCarbon Fire Box

By incomplete combustion of biomass from for example wood stoves black carbon containing particles can be emitted to the atmosphere. Black carbon containing particles in the atmosphere have at present time generated a lot of attention from various professional organizations, authorities, labelling systems and overall in the research landscape, because of the allegation of being the second greatest factor of the global climate changes next after carbon dioxide.  
 
Today, black carbon is not a measured emission factor in the wood stove industry or in most other industries involving combustion processes with either fossil fuels, biofuels or biomass burning. However, black carbon containing particles constitutes a portion of the already measured total particular mass today, but not specifically black carbon. It is a highly complicated subject, and there is no available measurement protocol nor accepted measurement method of measuring black carbon from wood stove smoke. Therefore, DAPO (the Danish trade organization of wood burning stoves and inset appliances) and Skamol A/S (Danish manufacturer of the most used insulation material, Vermiculite, for modern fireboxes) wanted to keep one-step ahead of the development of future less black carbon polluting fire box designs and probably future emission demands regarding black carbon emissions. 
 
At the time of the conference, the ongoing MST project (sponsored by the Danish Environmental Protection Agency) has already been on the road for over 2 years and nearly finished. Based on a thorough literature study and a measurement campaign (developed for the project) on eight modern stoves, a new test model fire box has been designed, CFD simulated and build. The next step will be to verify the prior defined guidelines and tools for producing a less black carbon polluting fire box to be applied in new stoves, if black carbon in the future becomes an isolated emission demand.

Mr René Hvidberg

Danish Techological Institute

19

Life Cycle Assessment (LCA) of a novel production process for biodiesel using yeast

Exploring the potential environmental impacts of future energy sources is important for identifying emerging sustainability challenges. Life Cycle Assessment (LCA) is a useful systems-based technique for eva"Exploring the potential environmental impacts of future energy sources is important for identifying emerging sustainability challenges. Life Cycle Assessment (LCA) is a useful systems-based technique for evaluating these impacts across the lifetime of the energy product and is commonly used in the environmental assessment of biofuels. 
 
Micro-organisms such as algae, fungi and yeast have been suggested as important sources of lipid that, following transesterification, can be used to produce biodiesel [1]. There have been a number of LCA studies conducted to date that have investigated the environmental implications of this technology; however, these have predominately focused on the use of algae as the microbial source. Yeast as a lipid source for biodiesel production has received far less LCA investigation in comparison. Despite this, yeast offers many advantages over an algal oil system as it does not require light energy in order to grow and can utilise a number of different biomass-derived sugar feedstocks. These aspects often contribute significantly to overall energy use and Greenhouse Gas (GHG) emissions associated with the algal oil production process. 
 
This scoping LCA presents an initial evaluation of the production process for microbial oil from the yeast Metschnikowia pulcherrima utilising a waste lignocellulosic feedstock for application of the lipid as a biofuel. In addition to providing useful results about the specific impacts of the process, this research tackles some of the methodological challenges associated with assessing new and emerging technology [2].  Results highlight the important environmental considerations needed as the technology progresses forward and provides a useful preliminary comparison with other biofuel production processes. This research underpins the future development of a comprehensive overall assessment of the yeast oil technology’s sustainability and long-term commercial viability. 
 
[1] Whiffin, F. et al. Bio. Biopro. Bioref. 10 2016
[2] Hetherington, A. C. et al. Int. J. LCA 19 2014
 
 

Dr Sophie Parsons

University of Bath

20

The effects of biomass flue gas impurities on amines for carbon capture

Biomass combustion and CCS (carbon capture and storage) are two technologies that are beginning to be used individually on a large scale to reduce carbon dioxide emissions in the power sector. However they have not yet been combined to permanently remove carbon dioxide from the earth's atmosphere, therefore my research looks at the potential for combining these two technologies. By investigating the fate of biomass inorganics during combustion and the effect of these species on carbon capture solvents we can assess the potential for the large scale combination of these technologies. 

Mr Diarmaid Clery

University of Leeds

21

Carbon balance of a land-use transition from grassland to SRC willow

The full effect of a transition from grassland to second-generation (2G) bioenergy on greenhouse gases and soil and ecosystem carbon is still relatively uncertain at present but with polices set to increase bioenergy production, more data are needed, particularly for model validation. We have quantified whole ecosystem carbon balance for a commercial 2G short rotation coppice (SRC) willow and a paired commercial grassland site for five years, spanning a harvest of the 2G crop, representing a full coppice cycle. This is complemented with the measurements of biomass carbon and soil measurements of GHG emissions, including  CO2, N2O and CH4, the three main GHGs.
 
In the first stage of the experiment, the grassland was harvested and left on site, reflecting farming practices with ragwort present. However as this is not common practice in the farming, the second stage of our data collection from summer 2016 onwards was to remove the harvested grass. In the first stage of the experiment it was found that the grassland was a net source of carbon whereas the SRC willow was a net sink. This means that results to date indicate that significant carbon savings can be achieved through the growth of SRC willow, compared to grassland at our site. It is possible however that with the biomass from the grassland removed from the system this effect may change. In addition to this, we are incorporating campaigns to measure trace gas emissions at real time measurement frequency, including CO2, N2O, CH4, NH3 and H2O in real time, enabling a more detailed investigation into the GHGs than previously available.

Dr Suzanne Milner

University of Southampton

22

The Combustion Characteristics of UK grown Birch and Sitka Spruce

Sustainably sourced wood biomass has the potential to produce low carbon and cost effective renewable energy, resulting in its increased use as an alternative to conventional fossil fuels. As such, in the UK there has been a substantial growth in both domestic and non-domestic wood fuel use, which has prompted a growing interest in utilising local sources of woodfuel. The composition of the UK’s forest and woodlands are diverse, consisting of a wide variety of different softwood and hardwood species. Of these, two of the most frequently found species are birch (Betula spp.) and Sitka spruce (Picea sitchensis), which account for approximately 23 million m³ and 180 million m³ of wood growing stock, respectively.
This research considers the differences in combustion characteristics between hardwood and softwood species sourced from different forest stands throughout the UK; specifically focusing on samples from birch and Sitka spruce specimens. In addition to the two species, the sample set contains wood obtained from different parts of individual trees, namely the stem, roots and branches. The samples have been characterised using ultimate and proximate analysis, while individual higher heating values have also been calculated. Thermogravimetric analysis has been used to ascertain the combustion differences between hardwood and softwood species and how this can further differ when considering the separate parts of the tree.

Mr Douglas Phillips

University of Leeds

24

Valorisation of early harvested miscanthus for unitisation in combustion via hydrothermal carbonisation

While miscanthus is currently being commercially utilised in both Europe and US as a bio-energy crop current applications are largely focused thermal conversion routes such as combustion. Such routes have fuel quality requirements set by the combustion system design. For miscanthus to best fit the combustion quality requirements conventional harvesting of miscanthus for energy purposes occurs late winter/ early spring, after the crop has fully senesced. This late harvest lowers above ground moisture, nitrogen, chlorine, ash and alkaline metals content through leaf fall and translocation of nutrients to the rhizome but this is also associated with a 30 % decline in dry matter yield. Moreover despite reductions in chlorine and alkaline metals issues such as slagging, fouling and corrosion can still persist during combustion.
 
A possible solution is harvesting the miscanthus in the autumn to achieve the highest possible yield per unit of land, followed by a pre-treatment which overcome the combustion limitations imposed by the inorganic chemistry of autumn harvested miscanthus. Hydrothermal carbonisation (HTC) is one such pre-treatment and this paper will demonstrate that HTC can overcome the combustion limitations imposed by the inorganic chemistry of autumn harvested miscanthus, offering both a maximised harvest yield while simultaneously producing a high quality solid fuel for combustion. Results will be presented for miscanthus harvested before and after winter as part of a cultivation trial and processed hydrothermally at 200⁰C and 250⁰C. Analysis of the metal and halogen content along with ash fusion testing of the autumn and winter derived fuels show significant reductions in the slagging propensity, fouling and corrosion risk of the fuel. Moreover significant improvements in energy density (18 MJ/kg to 28 MJ/kg), changes to combustion profiles and significant reductions in the resistance to milling make both autumn and winter fuels suitable for pulverised boiler and co-firing applications. 

Mr Aidan Smith

University of Leeds

25

Biomass Self-Ignition Characteristics during Handling and Storage: Hot Storage Basket Tests on Pellets and Powder

Biomass is a form of renewable energy that is gaining popularity each day as one of the means to combat global climate change. White wood pellets (WWP) from North America are a common biomass resource used in U.K. power stations to replace or partially replace (via co-firing) fossil fuel coal. Challenges present when it comes to storage (be it outdoor piles or indoors silos) or along the transportation line of different amount of biomass, include the self-ignition problem. In the present study, WWP in two forms – pelleted or pulverised (≤180µm) to represent biomass fuel storage and along the transportation line from storage to usage respectively were studied. Hot storage basket tests were conducted in accordance to BS EN 15188:2009, where biomass storage was experimented in a minimum of three different-sized baskets to represent biomass of different quantities. The main findings revolved around two major parameters – critical ignition temperature, TSI and ignition delay time, ti of the WWP samples when the samples were subjected to environment of different temperatures. Since the self-heating characteristics depend on the volume to surface ratio, TSI was seen to decrease as the biomass heap size increased. Similarly, the lower the TSI the longer the ignition delay time, ti. Upon getting the TSI and ti trends from the three sample sizes, extrapolations to much bigger sample size were performed. Excellent regression is seen for TSI which gives confidence in the scale up of the data to some extent, but there is far more uncertainty in the extrapolation of ti to larger scales.  TSI is higher for pellets compared to powder and decreases as the sample volume increases and finally converges at 25-35˚C for powder vs pellets respectively.

Prof Jenny Jones

University of Leeds

26

Mapping of UK bioenergy stakeholder expertise

"Bioenergy is renewable energy from biological sources used for heat, electricity, fuel, and chemical products, affecting from local to global scales. There are six identifiable and discrete steps in the bioenergy chain:
 
1 Sustainable ecosystem services 
As part of human activity, bioenergy should be environmentally oriented by bioenergy stakeholders to optimise systems.   
 
2 Feedstocks
Proper feedstock selection, handling and logistics drives bioenergy development.  Stakeholders go beyond biomass or waste production management, to include modified materials, by-products and residues.
 
3 Bioenergy conversion processes 
Conversion processes undergo development through designing, testing, controlling, intensification and optimisation. These stakeholder efforts include chemical and biochemical, electric and electrochemical, and thermal and thermochemical processes, and their combinations. Other related processes are clean up technologies, upgrading technologies, carbon capture and storage, or energy storage. 
 
4 Analysis and modelling 
Stakeholders use analysis and modelling to aid decision-makers for technology implementation and improvement.
 
5 Integration and technology demonstration 
This addresses process optimisation and recognises their distance from industrial applications. It also helps to improve strategic communication, create bioenergy networks and promote further research and development, and create new markets
.
6 Biomass based products 
The products need to be tested, evaluated and optimised by stakeholders for power generation, fuels or bio-products. Related with them, experts are also aware about their transportation to close the supply chain. 
 
Research Plan
This research focuses on identifying UK bioenergy stakeholders under those steps in the bioenergy chain. The objective is to provide a vision of how UK bioenergy expertise fits into the bioenergy sector and their research alignments. The presentation will review all relevant activities in the UK and present a picture of complementary research and development and begin to identify gaps and opportunities in the bioenergy field.

Dr Natalia Gomez-Marin

Aston University

27

Chemical Kinetic Studies of Biogas and Bio-Syngas Combustion

One hurdle hindering more widespread use of biogas and bio-syngas consists of their uncertain combustion behaviours due to the presence and interaction of multiple compounds within these fuel mixtures. To solve this problem, an economical way would be modelling the complex underlying physical and chemical processes taking place during its combustion in industrial systems. Such a strategy allows to greatly reduce the experimental costs while tremendously increasing (or even enabling in the first place) the reliability of predictions. Given the considerable computational costs involved, computational fluid dynamics (CFD) simulations of real industrial systems necessitates the utilisation of simplified chemical kinetic models which themselves are obtained from the systematic reduction of detailed reaction mechanisms. The accuracy and reliability of a reduced model are always inferior to those of the detailed parent mechanism. 
 
This study consisted of a thorough chemical kinetic evaluation of several detailed reaction mechanisms with respect to the combustion of biogas and bio-syngas. 63 experimental ignition delay profiles involving H2, CO, CO2, CH4, H2O and blends thereof have been employed for the evaluation and their discrepancies with the model predictions have been systematically calculated. The numerical prediction of pollutant formation has also been performed. Among other results, the formation of the greenhouse gas N2O has been predicted for p = 10 bar in lean mixtures containing both methane and hydrogen. More detailed results will be reported in the full-length paper. Overall, the results advocate the use of the GRI-mechanism 3.0 as the foundation for advanced CFD calculations such as Large Eddy Simulation. 

Prof Xi Jiang

Queen Mary University London

28

Waste to resource – whole systems modelling of circular bioeconomy

Considerable amount of carbon-containing or nutrient-rich waste resources are generated globally. In the UK, annual production of over 100 million tonnes of carbon-containing solid biowaste (household organic waste, food waste, green waste etc.) and above 14 million tonnes of forestry and agricultural residues and large amount of other waste such as sewage sludge provide significant opportunities (BIS 2015). They could be recovered via various routes to form high-value bio-products such as bioenergy, biofuels, bio-plastics and fertilisers, which shift us to a resource-circular bioeconomy. However, waste bioresource value chain involves the trade-offs between conflicting sustainability targets, interaction between macro-economy and benefits of individual stakeholder. This not only requires an understanding of the whole system at macro level, but also the stakeholders involved to achieve equilibrium solutions for the entire value chain,  considering the environmentally sustainable and economically viable development of waste bioresource sectors.
This study focused on an integrated multi-level modelling tool, combining process simulation and multi-objective optimisation for multi-echelon value chain design and equilibrium solutions. The model accounts for different actors involved in the bio-economy systems including the biomass growers, existing economic sectors (e.g. food, timber producers) and new bio-refinery sectors and distribution centres. The government is modelled as system regulator defining the marco-economy boundary conditions and implementing policies. Model is also configured to consider the natural capital resource competition issues i.e. competition of land and water natural resources between the food agricultural waste as biorefinery feedstock and the bioenergy crops exclusively grown for bio-sector conversion processes. Via a case study, this research highlights the insights the proposed framework could generate for bioresource value chain design at spatial and temporal scales and to explore trade-offs between economic targets and environmental issues involved in the waste resource recovery systems in the coming decades.

Dr Miao Guo

Imperial College London

29

Air Quality Impacts from Cookstove Emissions

Atmospheric aerosols impact air quality and climate. The global impact of ambient particulate matter pollution (PM2.5) in 2010 resulted in ~3.1 million deaths and ~3.1% of disability-adjusted life years (DALYs). This burden occurs predominantly in Asian and African countries where solid fuel combustion has remained high for decades. These solid fuels are mostly biomass and are predominantly burnt in poor-quality cookstoves with high-levels of incomplete combustion. 

In this work, the emissions levels of gaseous and volatile species are measured for typical fuels combusted using an African cookstove. The harmful species investigated include NOx and carbon monoxide. The levels of particulate species that are emitted have been analysed and quantified. The particulate matter is further investigated according to the levels of Polycyclic Aromatic Hydrocarbons (PAH) present, which are known to have serious health impacts. Finally, the effects on these emissions of substituting charcoal as a fuel instead of wood are compared. The air quality impacts of these results are considered with reference to the effects on persons using the cookstoves in their daily lives. 

Dr Amanda Lea-Langton

The University of Manchester

30

Measurement and Analysis of Bioenergy Greenhouse Gases: integrating GHGs into LCAs and the UK Biomass Value Chain Modelling Environment

MAGLUE is a Supergen Challenge project that aims to provide better understanding of crop and whole life cycle GHG emissions from a range of second generation bioenergy feedstocks.  Bioenergy will be required to achieve the UK target of emission reduction of 80% by 2050 relative to the 1990 emissions, but where this biomass is sourced, how it is grown and utilized will have wide-scale implications for both crop and whole life cycle GHG balance. The aim of MAGLUE is to investigate these uncertainties, developing insight for the UK bioenergy supply out to 2050.
 
Firstly, we are collecting field-based GHG data for a number of land use change and crop management scenarios. We are investigating the GHG impacts of crop reversions from bioenergy crops back to arable and grassland and building an evidence base of soil data from long-term land use changes. To complement these empirical studies, we are modelling the impacts of bioenergy crop growth on GHG emission for both UK grown and biomass sourced from overseas. Finally, through the use of case studies, we are closing the knowledge gap of LUC to look at the potential of bioenergy crops grown across the world. These case studies are targeted to North America, South-east Asia, Eastern Europe, and Brazil, each with a different major bioenergy crop or management strategy.

Prof Gail Taylor

University of Southampton

31

An investigation into multicomponent fuel blends using pyrolysis oil, marine fuel and alternative blend components

This study investigates the miscibility and properties of novel fuel blends containing fast pyrolysis oil, marine gas oil (MGO) and other blend components. Blend components tested include 1-butanol, glycerol, butyric acid, oleic acid and butyl glycol. Fast pyrolysis oil has had limited success as a fuel for engines, so by blending it may be possible to extend its application beyond boiler use.
 
A number of the blend components can be readily manufactured from biomass. Glycerol is a by-product of biodiesel manufacture and with the large increase in biodiesel production there is an excess of glycerol in the marketplace. 1-butanol and butyric acid can be obtained from fermentation, oleic acid from vegetable oils and pyrolysis oil is made by the thermochemical conversion of biomass.
 
The objective of the work was to improve understanding of fast pyrolysis oil and marine fuel blends. The results were used to create phase diagrams establishing the boundary between single phase and phase separated blends. The properties of the homogeneous blends were measured to establish blends of interest for further development as potential marine fuels. 
 
The blends cover a spectrum of compositions in order to build the phase diagrams. Samples were left to settle for 48 hrs before visual inspection to establish homogeneity. Single phase blends were tested for key characteristics of flash point, viscosity and water content.
 
The results indicate it is possible to create stable single phase multicomponent blends containing fast pyrolysis oil, MGO and other blend components. Some interesting blend recipes have been identified for further development, as well as components that are not suitable.
 
This study represents a step forward in the understanding and development of fast pyrolysis oil marine fuel blends. The work forms part of the ReShip Project which is funded by Norwegian industry partners and the Research Council of Norway.

Dr Stuart Jones

Aston University

33

Biomass pre-treatment by torrefaction

The aim of this study was to evaluate the impact of torrefaction temperature on the quality and thermochemical properties of the thermally pre-treated biomass. Thermogravimetric analysis (TGA) was used for the assessment of biomass decomposition kinetics, volatile matter and ash content. Analytical stage pyrolysis (Py-GC-MS/FID) was used to study the decomposition of holocellulose present in biomass during the thermal treatment at the temperature range between 200 and 300°C. Bench-scale torrefaction experiments were carried out on beech wood and willow SRC in a batch reactor of 250g capacity at the following temperatures: 225°C, 250°C, 275°C and 300°C. Raw and torrefied feedstocks were analysed for ash and moisture content (ASTM methods); carbon, hydrogen, nitrogen and oxygen content. A temperature range between 260-280°C was judged to be optimal for high mass yields of torrefied biomass whilst minimising carbon loss.  The energy density of the torrefied biomass was found to be between 1.15 and 1.40 times as much as the raw biomass for torrefaction at 275 and 300°C respectively. The condensed liquids from the torrefaction experiments were analysed using gas chromatography-mass spectrometry (GC-MS). The main components in the liquid were light organic products (acetic acid, furfural, 3-furaldehyde) and at higher temperatures (above 275°C) monoaromatics (e.g. 2,6-dimethoxy-phenol; 2-methoxy-4-(1-propenyl)-phenol; 2,5-dimethoxy-4-ethylbenzaldehyde).

Dr  Daniel Nowakowski

Aston University

35

Studies on the effects of feedstock particle size in biomass torrefaction processes

Torrefaction is a means of pre-processing biomass fuels to improve energy density and handling and milling properties. Commercial, large scale torrefaction for producing bulk fuel supplies require optimisation of energy balances and quality control in the processing.  Both of these are strongly affected by the consistency of heat transfer and residence time in the torrefaction oven. Heat transfer to individual particles of the biomass feedstock will vary depending on the particle size and shape. Internal heat transfer will also be affected by variability in material thermal conductivity.   

A study to investigate the effects of particle size on the degree and consistency of torrefaction has been carried out using lab-scale experimental studies and modelling of heat transfer and devolatilisation. Experimental studies on particles of eucalyptus and willow were undertaken using thermo-gravimetric analysis. A heat transfer model was developed to simulate the conditions of the experiment and also for conditions expected in larger torrefaction processing plant. Together with the particle temperature profiles derived from the heat transfer model,  FG-BioMass pyrolysis modelling software was used to predict the relative yields of remnant char and released volatile products. Experimental results were used to validate the modelling predictions and the validated model was used to investigate the effects of variable particle size on the variability in torrefied product composition.
 

Mr Patrick Mason

University of Leeds

37

Pilot-scale Intermediate Pyrolysis of Organic Fraction of Municipal Solid Waste and Utilisation of Aqueous Phase Product in Continuous Anaerobic Digestion Trial

There are approximately 50 million tonnes of municipal solid waste (MSW) produced in UK each year. The majority of this waste is currently disposed of by either incineration or landfill, both of which are unsustainable practices as they are costly, lead to an increase in greenhouse gas emissions and use up land which could be otherwise used for arable farming.
 
The current research is aiming to develop sustainable and societally acceptable means of recovering energy from the non-source segregated organic fraction of MSW (OFMSW) through a combined thermal (intermediate pyrolysis) and biological (anaerobic digestion) conversion process.
 
The feedstock used in the present work is densified shredded (<10 mm) OFMSW particles that have been segregated from processed refuse. The material contains approximately 51 % wt. moisture and 16 %wt. ash, as supplied by a commercial MSW treatment plant.
 
Intermediate pyrolysis of OFMSW feedstock was carried out in a pilot-scale Pyroformer intermediate pyrolysis system and over 50 kg of the material were processed at 500ºC. The pyrolysis liquid was produced in two separated fractions (organic and aqueous) and both fractions were collected and characterised. The mass balance of the pyrolysis process and energy contents of the pyrolysis liquid, gases and solid products were evaluated and analysed.
 
The aqueous fraction of the liquid products was examined for its anaerobic biodegradability. Initially, batch tests were used (such as anaerobic inhibition tests and biochemical methane potential tests) to gain an understanding of the toxicity to methanogenic activity and the potential for methane production. Finally, the aqueous fraction was used in continuous-reactor studies using different inoculum-to-substrate ratios and hydraulic retention times.  

Dr Yang Yang

Aston  University

38

Briquetting of waste biomass for pyrolysis

Large volumes of agricultural waste are generated annually in both developed and developing countries. Most of the biomass residues which can be used directly or indirectly as fuel, are considered as waste products and are either burnt in open air (without heat recovery) or dumped to decompose in uncontrollable ways. These practices are largely contributing to increased greenhouse gas emissions and environmental pollution. Published studies on pyrolysis shows the use of biomass in traditional form. However, using biomass in traditional form for energy generation is challenging. This is because biomass materials have irregular shapes and sizes, low bulk densities, and generally high moisture content thus making effective handling, transportation, storage and use difficult. 

In this study, maize cobs were characterized and the effect of compacting pressure, feedstock moisture content, compacting temperature and particles size on properties of briquettes were investigated. Density increased from 982.33 to 1030.13 kg/m3 with an increase in compacting pressure (150-250 MPa). Strength and durability were maximum at compacting pressure of 200 MPa. However, compacting pressure had no significant impact on proximate properties and high heating value of briquettes. Density decreased from 1030.13 to 673.46 kg/m3 with an increase in moisture content (6-20%). The mechanical properties decreased with increase in moisture content. Density, durability and strength increased with increase in compacting temperature (20-80 oC) and a decrease in particle size (1.0-4.5 mm). Maize cobs contained 6.12% moisture, 3.24% ash, 76.06% volatile matter and  14.58 % fixed carbon with an energy content of 18.92 MJ/kg. From chemical analysis, it was found that the maize cobs had 46.92 % carbon, 8.13% hydrogen, 2.79 % nitrogen and 42.16% oxygen.

Mr David Kilama Okot

Newcastle University

40

Sustainable energy production via fast pyrolysis of conservation biomass

Waste biomass is generated during the conservation management of semi-natural habitats, and represents an unused resource and potential bioenergy feedstock that does not compete with food production.  Thermogravimetric analysis was used to characterise a representative range of biomass generated during conservation management in Wales. Of the biomass types assessed, those dominated by rush (Juncus effuses) and bracken (Pteridium aquilinum) exhibited the highest and lowest volatile compositions respectively and were selected for bench scale conversion via fast pyrolysis. Each biomass type was ensiled and a sub-sample of silage was washed and pressed. Demineralization of conservation biomass through washing and pressing was associated with higher oil yields following fast pyrolysis. The oil yields were within the published range established for the dedicated energy crops miscanthus and willow. In order to examine the potential a multiple output energy system was developed with gross power production estimates following valorisation of the press fluid, char and oil. If used in multi fuel industrial burners the char and oil alone would displace 3.9E5 tonnes per year of No. 2 light oil using Welsh biomass from conservation management. Bioenergy and product development using these feedstocks could simultaneously support biodiversity management and displace fossil fuels, thereby reducing GHG emissions. Gross power generation predictions show good potential.

Dr John Corton

IBERS

 

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