Advanced Plasma Power

Swindon, United Kingdom

Advanced Plasma Power

Swindon, United Kingdom

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Materazzi M.,University College London | Lettieri P.,University College London | Mazzei L.,University College London | Taylor R.,Advanced Plasma Power | Chapman C.,Advanced Plasma Power
Fuel | Year: 2015

To accelerate progress in the industrial use of RDF as an alternative fuel in gasification plants, the problems associated with hazardous solid residues and ash deposition must be resolved. The practical approach to reduce these problems must be aimed at preventing the accumulation of fly ash/condensable vapours on heat transfer surface areas while minimising the amount of residual materials that have to be treated before the disposal. One such approach is adopted in an advanced two-stage thermal process which incorporates a plasma processing stage for conditioning the gas generated from a primary waste gasification unit, primarily for the treatment of household and industrial wastes. This paper presents a comprehensive examination of ashes sampled under different operational conditions and in different locations of a two-stage fluid bed-plasma demonstration plant. A demonstration test miming the normal commercial operation was conducted over 44 h of operation with RDF from a standard UK municipal solid waste. The results are presented according to solid samples composition, gas composition, and further specific data (e.g., enrichment factor, XRD analysis, leaching test, etc.). An investigation on pollutant removal from the hot syngas, focusing on the partitioning and chemistry of sulphur and chlorine along with other relevant components, is also carried out. Experimental trials revealed a reduced extent of alkali and metals availability in the gas phase, i.e. a minor deposit forming potential into downstream equipment. From 85% to 91% of the fly ash was captured and vitrified within the plasma converter and made non-leachable with respect to non-volatile heavy metals, allowing for near complete landfill diversion. © 2015 Elsevier Ltd. All rights reserved.


Materazzi M.,University College London | Lettieri P.,University College London | Mazzei L.,University College London | Taylor R.,Advanced Plasma Power | Chapman C.,Advanced Plasma Power
Fuel Processing Technology | Year: 2014

This work focuses on systematic studies of the plasma reforming of newly evolved vapors from a fluid bed gasifier, and on the resulting evolution of individual gaseous cracking products to hydrogen-rich syngas. The aim of this study is to compare some previously developed mechanisms of thermal cracking and to identify the main elementary reactions and the most sensible ones for tar decomposition in a two-stage process. Evaluation of plasma chemistry is performed by a comparison between experimental data and thermal kinetic predicted results. Distribution analysis of condensable organics shows that for all the representative species, the levels of tars are distinct in the first stage and almost negligible after the plasma treatment. Under the given reaction conditions, the organic cracking products such as methane and C 2-species are completely converted to carbon monoxide and hydrogen, and no soot significantly formed. Oxygen atoms initially formed from CO 2 were identified as the major active species involved in the oxidative decomposition of hydrocarbon intermediates and soot precursors. As a result, a two-stage system shows better reforming results, large treatment capacity and almost complete carbon conversion. © 2014 Published by Elsevier B.V.


Materazzi M.,University College London | Lettieri P.,University College London | Mazzei L.,University College London | Taylor R.,Advanced Plasma Power | Chapman C.,Advanced Plasma Power
Fuel | Year: 2013

Tar generation and ash disposal represent the strongest barrier for use of fluid bed gasification for waste treatment, whereas sufficing for both is only possible with expensive cleaning systems and further processing. The use of plasma within an advanced two-stage thermal process is able to achieve efficient cracking of the complex organics to the primary syngas constituents whilst limiting the electric power demand. This study focused on the thermodynamic assets of using a two-stage thermal process over the conventional single-stage approach. These include, for example, the fact that the primary thermal waste decomposition is performed in conditions of optimal stoichiometric ratio for the gasification reactants. Furthermore, staging the oxidant injection in two separate intakes significantly improves the efficiency of the system, reducing the plasma power consumption. A flexible model capable of providing reliable quantitative predictions of product yield and composition after the two-stage process has been developed. The method has a systematic structure that embraces atom conservation principles and equilibrium calculation routines, considering all the conversion stages that lead from the initial waste feed to final products. The model was also validated with experimental data from a demonstration plant. The study effectively demonstrated that the two-stage gasification system significantly improves the gas yield of the system and the carbon conversion efficiency, which are crucial in other single stage systems, whilst maintaining high energy performances. © 2013 Elsevier Ltd. All rights reserved.


Stein R.,Advanced Plasma Power
Renewable Energy Focus | Year: 2012

IN TERMS of the balance between the energy and resources we consume and the waste we produce, the world is fast approaching a tipping point. A new generation of energy from waste technologies can help, as Rolf Stein explains © 2012 Elsevier Ltd.


Materazzi M.,University College London | Lettieri P.,University College London | Mazzei L.,University College London | Taylor R.,Advanced Plasma Power | Chapman C.,Advanced Plasma Power
Fuel Processing Technology | Year: 2015

Abstract Waste gasification is considered a valuable and sustainable solution to the production of clean energy (via gas turbines or gas engines) and bio-fuels, such as synthetic natural gas and bio-hydrogen, provided that the syngas produced in the gasifier is free of condensable tars and organic sulphur contaminants that cause equipment fouling and deactivation of catalytic stages downstream. In particular, catalytic reaction stages are highly sensitive to specific trace contaminants (e.g. PAHs, thiophenes, etc.), necessitating the use of additional cleaning operations to remove these residues to levels where the catalyst degradation is acceptable. In this work, the use of thermal plasma (coupled with primary waste treatment) to completely reform tars and organic sulphur compounds to simple gaseous products (predominantly H2 and CO) is assessed. To this end, a 20-hour waste gasification run was performed on a two-stage fluid bed-plasma demonstration plant to investigate the tar evolution in the syngas, with special attention on the chemistry of generic and sulphur-substituted aromatics within the plasma stage. The organic fraction in the gas phase was found to be completely reformed under plasma conditions, leaving essentially CO, H2 and H2S as ultimate products. In particular, reduction efficiencies typically exceeded 96%v/v for complex organics (e.g. PAH) and thiophenes were observed. The syngas, after a tertiary simplified gas cleaning process, is suitable for high efficiency power generation, or conversion to a fuel gas capable of injection into national or industrial supply grids. © 2015 Elsevier B.V.


Morrin S.,University College London | Lettieri P.,University College London | Chapman C.,Advanced Plasma Power | Mazzei L.,University College London
Waste Management | Year: 2012

Gasification of solid waste for energy has significant potential given an abundant feed supply and strong policy drivers. Nonetheless, significant ambiguities in the knowledge base are apparent. Consequently this study investigates sulphur mechanisms within a novel two stage fluid bed-plasma gasification process. This paper includes a detailed review of gasification and plasma fundamentals in relation to the specific process, along with insight on MSW based feedstock properties and sulphur pollutant therein. As a first step to understanding sulphur partitioning and speciation within the process, thermodynamic modelling of the fluid bed stage has been performed. Preliminary findings, supported by plant experience, indicate the prominence of solid phase sulphur species (as opposed to H 2S) - Na and K based species in particular. Work is underway to further investigate and validate this. © 2011 Elsevier Ltd.


Chapman C.D.,Advanced Plasma Power | Taylor R.J.,Advanced Plasma Power | Faraz A.,Advanced Plasma Power
Proceedings of Institution of Civil Engineers: Waste and Resource Management | Year: 2014

Oxygen-based gasification offers advantages over air-based gasification such as reduced capital costs or similar operating costs combined with the potential to use the higher calorific value syngas in high-efficiency power generation systems, greatly enhancing revenue creation potential. This paper reports on the effects of increasing oxygen purity on the gasification processes and includes a techno-economic assessment that uses both theoretical and experimental observations involving the gasification of a waste fuel. Syngas quality is dramatically affected by the purity of the oxygen used in gasification, with increased purity leading to reduced levels of nitrogen, increased levels of combustible gas components and enhanced calorific values. The calorific value of air-based gasification syngas is 4-5 MJ/Nm3, but increases to 10-12 MJ/Nm3 with oxygen-based gasification. In addition, gasification performance, as measured by cold gas conversion efficiency, is also affected by the purity of the oxygen used in gasification, with levels rising from 40% for air-based systems to 80% in oxygen-based systems. The results of this study indicate that capital costs associated with oxygen-based gasification can be as much as 40% less than a comparable scale air-based gasification system. In addition, investment returns can be considerably boosted from the use of oxygen-based gasification.


Morrin S.,University College London | Lettieri P.,University College London | Chapman C.,Advanced Plasma Power | Taylor R.,Advanced Plasma Power
Waste Management | Year: 2014

Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed.Notable SO2 and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO2's generation. The response of COS to sulphur in the feed was quite prompt, whereas SO2 was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO2 generation. The more reducing gas phase regions above the bed would have facilitated COS - hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling. © 2013 Elsevier Ltd.

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