Advanced Plasma Power Applied

Swindon, United Kingdom

Advanced Plasma Power Applied

Swindon, United Kingdom
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Tagliaferri C.,University College London | Clift R.,University of Surrey | Lettieri P.,University College London | Chapman C.,Advanced Plasma Power Applied
International Journal of Life Cycle Assessment | Year: 2017

Purpose: Liquefied natural gas (LNG) is expected to become an important component of the UK’s energy supply because the national hydrocarbon reserves on the continental shelf have started diminishing. However, use of any carbon-based fuel runs counter to mitigation of greenhouse gas emissions (GHGs). Hence, a broad environmental assessment to analyse the import of LNG to the UK is required. Methods: A cradle to gate life cycle assessment has been carried out of a specific but representative case: LNG imported to the UK from Qatar. The analysis covers the supply chain, from gas extraction through to distribution to the end-user, assuming state-of-the-art facilities and ships. A sensitivity analysis was also conducted on key parameters including the energy requirements of the liquefaction and vaporisation processes, fuel for propulsion, shipping distance, tanker volume and composition of raw gas. Results and discussion: All environmental indicators of the CML methodology were analysed. The processes of liquefaction, LNG transport and evaporation determine more than 50% of the cradle to gate global warming potential (GWP). When 1% of the total gas delivered is vented as methane emissions leakage throughout the supply chain, the GWP increases by 15% compared to the GWP of the base scenario. The variation of the GWP increases to 78% compared to the base scenario when 5% of the delivered gas is considered to be lost as vented emissions. For all the scenarios analysed, more than 75% of the total acidification potential (AP) is due to the sweetening of the natural gas before liquefaction. Direct emissions from transport always determine between 25 and 49% of the total eutrophication potential (EP) whereas the operation and maintenance of the sending ports strongly influences the fresh water aquatic ecotoxicity potential (FAETP). Conclusions: The study highlights long-distance transport of LNG and natural gas processing, including sweetening, liquefaction and vaporisation, as the key operations that strongly affect the life cycle impacts. Those cannot be considered negligible when the environmental burdens of the LNG supply chain are considered. Furthermore, the effect of possible fugitive methane emissions along the supply chain are critical for the impact of operations such as extraction, liquefaction, storage before transport, transport itself and evaporation. © 2017 The Author(s)

Tagliaferri C.,University College London | Evangelisti S.,University College London | Clift R.,University of Surrey | Lettieri P.,University College London | And 2 more authors.
Journal of Cleaner Production | Year: 2016

This study integrates the Life Cycle Assessment (LCA) of thermal and biological technologies for municipal solid waste management within the context of renewable resource use for methane production. Five different scenarios are analysed for the UK, the main focus being on advanced gasification-plasma technology for Bio Substitute natural gas (Bio-SNG) production, anaerobic digestion and incineration. Firstly, a waste management perspective has been taken and a functional unit of 1 kg of waste to be disposed was used; secondly, according to an energy production perspective a functional unit of 1 MJ of renewable methane produced was considered. The first perspective demonstrates that when the current energy mix is used in the analysis (i.e. strongly based on fossil resources), processes with higher electric efficiency determine lower global warming potential (GWP). However, as the electricity mix in the UK becomes less carbon intensive and the natural gas mix increases the carbon intensity, processes with higher Bio-SNG yield are shown to achieve a lower global warming impact within the next 20 years. When the perspective of energy production is taken, more efficient technologies for renewable methane production give a lower GWP for both current and future energy mix. All other LCA indicators are also analysed and the hot spot of the anaerobic digestion process is performed. © 2016 Elsevier Ltd. All rights reserved.

Tagliaferri C.,University College London | Clift R.,University of Surrey | Lettieri P.,University College London | Chapman C.,Advanced Plasma Power Applied
International Journal of Life Cycle Assessment | Year: 2016

Purpose: Following the boom of shale gas production in the USA and the decrease in the US gas prices, increasing interest in shale gas is developing in many countries holding shale reserves and exploration is already taking place in some EU countries, including the UK. Any commercial development of shale gas in Europe requires a broad environmental assessment, recognizing the different European conditions and legislations. Methods: This study focuses on the UK situation and estimates the environmental impacts of shale gas using life-cycle assessment (LCA); the burdens of shale gas production in the UK are compared with the burdens of the current UK natural gas mix. The main focus is on the analysis of water impacts, but a broad range of other impact categories are also considered. A sensitivity analysis is performed on the most environmentally criticized operations in shale gas production, including flowback disposal and emission control, by considering a range of possible process options. Results and discussion: Improper waste water management and direct disposal or spills of waste water to river can lead to high water and human ecotoxicity. Mining of the sand and withdrawal of the water used in fracking fluids determine the main impacts on water use and degradation. However, the water degradation of the conventional natural gas supply to the UK is shown to be even higher than that of shale gas. For the global warming potential (GWP), the handling methods of the emissions associated with the hydraulic fracturing influence the results only when emissions are vented. Finally, the estimated ultimate recovery of the well has the greatest impact on the results as well as the flowback ratio and flowback disposal method. Conclusions: This paper provides insights to better understand the future development of shale gas in the UK. Adequate waste water management and emission handling significantly reduce the environmental impacts of shale gas production. Policy makers should consider that shale gas at the same time increases the water consumption and decreases the water degradation when compared with the gas mix supply. Furthermore, the environmental impacts of shale gas should be considered according to the low productivity that force the drilling and exploitation of a high number of wells. © 2016 The Author(s)

Evangelisti S.,University College London | Tagliaferri C.,University College London | Clift R.,University of Surrey | Lettieri P.,University College London | And 2 more authors.
Waste Management | Year: 2015

In the past, almost all residual municipal waste in the UK was landfilled without treatment. Recent European waste management directives have promoted the uptake of more sustainable treatment technologies, especially for biodegradable waste. Local authorities have started considering other options for dealing with residual waste. In this study, a life cycle assessment of a future 20. MWe plant using an advanced two-stage gasification and plasma technology is undertaken. This plant can thermally treat waste feedstocks with different composition and heating value to produce electricity, steam and a vitrified product. The objective of the study is to analyse the environmental impacts of the process when fed with seven different feedstocks (including municipal solid waste, solid refuse fuel, reuse-derived fuel, wood biomass and commercial & industrial waste) and identify the process steps which contribute more to the environmental burden. A scenario analysis on key processes, such as oxygen production technology, metal recovery and the appropriate choice for the secondary market aggregate material, is performed. The influence of accounting for the biogenic carbon content in the waste from the calculations of the global warming potential is also shown. Results show that the treatment of the refuse-derived fuel has the lowest impact in terms of both global warming potential and acidification potential because of its high heating value. For all the other impact categories analysed, the two-stage gasification and plasma process shows a negative impact for all the waste streams considered, mainly due to the avoided burdens associated with the production of electricity from the plant. The plasma convertor, key characteristic of the thermal process investigated, although utilising electricity shows a relatively small contribution to the overall environmental impact of the plant. The results do not significantly vary in the scenario analysis. Accounting for biogenic carbon enhanced the performance of biomass and refuse-derived fuel in terms of global warming potential. The main analysis of this study has been performed from a waste management perspective, using 1. ton of waste as functional unit. A comparison of the results when 1. kWhe of electricity produced is used as functional unit shows similar trends for the environmental impact categories considered. © 2015 Elsevier Ltd.

Ray R.,Advanced Plasma Power Applied | Taylor R.,Advanced Plasma Power Applied | Chapman C.,Advanced Plasma Power Applied
Process Safety and Environmental Protection | Year: 2012

The Gasplasma ® process developed by APP is an advanced thermal conversion (ATC) technology which has been developed for the treatment of household and trade wastes and has also been successfully applied to the handling of wastes derived from landfill and would be capable of achieving effective energy conversion when utilised as an integrated part of the Enhanced Landfill Mining (ELFM) concept. The core Gasplasma ® technology comprises a two-stage thermal treatment system - firstly, a fluidizing bed gasifier which converts the wastes to a crude syngas using oxy-steam and, secondly, a plasma converter that efficiently cracks problematic tars in the raw syngas to produce a reformed and clean syngas suitable for generating electrical power in gas engines and also recovering an environmentally stable vitrified product for use as a secondary aggregate material. The utilization of oxy-steam as a gasifying agent greatly reduces the syngas volume compared to other ATC processes and incineration and hence reduces the cost of the gas cleaning system while improving the efficiency of the process. By adopting this two-stage approach, high energy conversion (74-90%) and carbon conversion (95 ± 1.6%) efficiencies were achieved with the Gasplasma ® plant that compare favourably with published efficiencies data. The calculated net exportable power generation efficiency for a commercial scale plant is significantly in excess of 25%. This compares well with the published figures of 17.7-23% for fluidized bed technologies processing MSW. © 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Taylor R.,Advanced Plasma Power Applied | Ray R.,Advanced Plasma Power Applied | Chapman C.,Advanced Plasma Power Applied
Fuel | Year: 2013

The disposal of End-of-Life Vehicles (ELVs) results in a highly heterogeneous polymeric waste stream of Automobile shredder residue (ASR). Within Europe, strict legislation, such as the End-of-Life Vehicle Directive and the Landfill Directive, has imposed targets for reducing this waste stream and diverting the material away from landfill. One pathway open to recyclers is to thermally process these wastes, but the presence of chlorine and metallic species can present challenges to traditional incineration technologies. This paper discusses the use of Gasplasma®, an advanced thermal treatment technology, comprising fluidised bed oxy-steam gasification followed by plasma treatment, for ASR, refuse derived fuel (RDF) and blends of ASR and RDF wastes. The work demonstrates the ability to process these highly heterogeneous materials achieving high energy conversion (87-94%) and virtually complete carbon conversion, producing a calorific synthetic gas (syngas) capable of being used for power generation or as a chemical feedstock. The actual conversion efficiency achieved is dependent on feed chemistry and properties. The study also shows that ash components of the feed material can be transformed into an environmentally stable vitrified product. © 2012 Elsevier Ltd. All rights reserved.

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