Plasma Gasification Research Articles

Thermodynamic Performance of a High Efficient Power Plant Based on Faecal Biomass Gasification, Solid Oxide Fuel Cells and Micro Steam Turbine

Affordable sanitation around the world with the recovery of valuable energy and clean water from faecal biomass in an off-grid system is a challenge. A novel small scale combined heat and power (CHP) toilet system concept has been optimized which generate power very efficiently and produce clean water. The system combines a dryer, a plasma gasifier, and a gas cleaning unit with an ambient pressure solid oxide fuel cell (SOFC) stack and a micro steam turbine (MST). The gasifier uses additional heat supplied from the combustion of stack depleted fuel. With this concept, syngas with high heating value can be produced which can be efficiently converted in a SOFC system. This is reflected by the net electrical efficiency of the integrated system configuration of the order of 40%. Additional power is produced combining it with an MST and an efficiency increase of the order of 20% is achieved.

Valorization of thermal treatment residues in Enhanced Landfill Mining: environmental and economic evaluation

Enhanced Landfill Mining is an innovative concept which allows the recovery of land, re-introduction of materials to the material cycles and recovery of energy from a considerably large stock of resources held in landfills. Plasma gasification is a viable candidate for combined energy and material valorization in the framework of Enhanced landfill Mining. Besides energy production, plasma gasification also delivers an environmentally stable vitrified residue called plasmastone, which can be converted into building materials. This paper presents an environmental and economic evaluation of the valorization of thermal treatment residues (plasmastone) in the context of Enhanced Landfill Mining. The most common valorization route, that is, the treatment of plasmastone via production of aggregates, is compared with two other possible, higher added value applications, which are inorganic polymer production and blended cement production. The evaluation is based on life cycle assessment and life cycle costing. The study suggests that the environmental and economic performances of the valorization routes depend mainly on the quality and quantity of the final products produced from a certain amount of plasmastone. The materials with the greatest contribution to potential global warming and to the net present value of the valorization scenarios are the process input materials of sodium silicate, sodium hydroxide and cement. The study concludes that the plasmastone valorization via inorganic polymer production yields higher environmental benefits, while the blended cement production provides higher economic profits. Plasmastone valorization via aggregates production does not yield economic or environmental benefits. Given the trade-off between environmental and economic performances, we conclude that the decisions regarding the selection of appropriate valorization routes should be made cautiously to obtain optimal environmental benefits and economic profits.

Review of current technologies used in municipal solid waste-to-energy facilities in Canada

The increasing amounts of municipal solid waste produced accompanied with the rising need for energy has caused a growth in the popularity of waste-to-energy (WTE) facilities as waste and energy solutions for many regions in Canada. The recent commercially viable WTE facilities across Canada show that the main technologies used in Canada are incineration, gasification, and plasma gasification. The aim of this study is to present these WTE technologies through the examination of case studies taken from the existing facilities across Canada. Background information on case studies, information on the WTE process, and a comparison highlighting the differences between the facilities are discussed.

Energy Generation from Municipal Solid Waste by Innovative Technologies – Plasma Gasification

The growing population all around the world has increased the quantum of solid waste the disposal of which has become a complex task to the municipal authorities. In search of a suitable remedy to this problem we have arrived at a number of varieties of waste management methods and strategies for dealing with municipal solid waste. These technologies help to generate energy in the form of heat, electricity and fuel and also remarkably reduce the diversion of biomass waste from landfill. The process of plasma gasification is one among those successful proven technologies of producing energy from waste. Gasification is a process in which a solid material containing carbon, such as coal or biomass, is converted into a gas called syngas which contains hydrogen and carbon monoxide. The focus of the paper is to analyze the process of plasma gasification and also to propose a critical assessment of MSW. It also aims to compare the performance of the process to that of the conventional energy recovery methods.

ICOPE-15-C091 An experimental system established on plasma gasification for municipal solid waste

ICOPE-15-C091 An experimental system established on plasma gasification for municipal solid waste

A review of technologies and performances of thermal treatment systems for energy recovery from waste

The aim of this work is to identify the current level of energy recovery through waste thermal treatment. The state of the art in energy recovery from waste was investigated, highlighting the differences for different types of thermal treatment, considering combustion/incineration, gasification and pyrolysis. Also different types of wastes – Municipal Solid Waste (MSW), Refuse Derived Fuel (RDF) or Solid Refuse Fuels (SRF) and some typologies of Industrial Waste (IW) (sludge, plastic scraps, etc.) – were included in the analysis. The investigation was carried out mainly reviewing papers, published in scientific journals and conferences, but also considering technical reports, to gather more information.In particular the goal of this review work was to synthesize studies in order to compare the values of energy conversion efficiencies measured or calculated for different types of thermal processes and different types of waste.It emerged that the dominant type of thermal treatment is incineration associated to energy recovery in a steam cycle. When waste gasification is applied, the produced syngas is generally combusted in a boiler to generate steam for energy recovery in a steam cycle. For both the possibilities – incineration or gasification – cogeneration is the mean to improve energy recovery, especially for small scale plants. In the case of only electricity production, the achievable values are strongly dependent on the plant size: for large plant size, where advanced technical solutions can be applied and sustained from an economic point of view, net electric efficiency may reach values up to 30–31%. In small-medium plants, net electric efficiency is constrained by scale effect and remains at values around 20–24%. Other types of technical solutions – gasification with syngas use in internally fired devices, pyrolysis and plasma gasification – are less common or studied at pilot or demonstrative scale and, in any case, offer at present similar or lower levels of energy efficiency.

Sewage Sludge-to-Power

This paper presents the results of modeled investigations of a developed sewage sludge (biosolids) plasma treatment complex. This includes a multistage plasma sewage gasifier, high-efficient heat recovery system, and power generation unit based on a gas engine. Investigations of the treatment complex efficiency are carried out, critical parameters of the process, including specific power consumptions for the own needs, are defined for operation on sewage sludge with 24.6% humidity. Obtained results are planned to be used for the plasma gasifier geometry optimization and further system prototyping.

Effect of gas–slag interaction on valorisation of refuse derived fuel treated with plasma gasification

During gasification of refuse derived fuel (RDF) to produce syngas in a system in which a melt is also produced, the gasified organic fraction of the RDF is in contact with the molten inorganic fraction, i.e. a slag. Examples of such systems are plasma gasifiers, in which crude syngas is further cracked in a plasma converter. Depending on the degree of gas–slag interaction, their compositions may vary and influence the valorisation potential of both resources. To evaluate the influence of this interaction, a pseudo-kinetic model was developed based on local thermodynamic equilibrium between the gas phase and part of the slag phase. The interaction level was accounted for by varying the amount of the slag that equilibrates with the gas. The valorisation potential of the resulting gas and slag phases was evaluated in terms of the heat of combustion and the mineralogy after cooling, respectively. Engineering of the slag composition was made through lime-rich addition. The influence of waste composition on the gas/slag properties and the production of a metal phase was investigated.

Исследование процесса плазменной газификации древесной биомассы различной влажности

Исследование процесса плазменной газификации древесной биомассы различной влажности

Unsteady state analysis of free-burning arcs in a 3-Phase AC plasma torch: comparison between parallel and coplanar electrode configurations

An MHD model with parallel electrode configuration was developed to determine the influence of the electrode configuration on 3-Phase arc discharge behavior. The results obtained with this model were compared to previous results obtained with coplanar graphite electrode configuration. Results show a different arc behavior in both cases. In a parallel electrode configuration, the arcs are not confined within the inter-electrode gap as in coplanar electrode configuration. These results were compared to the arc behavior observed with a high-speed video-camera in a nitrogen atmosphere with a high correlation. The influence of frequency and current was also investigated. By adjusting the electrode configuration, the arc elongation and the dissipated power could be controlled. According to the application, such as plasma-assisted combustion, plasma gasification, plasma spray or for different plasma gases, the electrode configuration could play a key role to improve the discharge or operation. This study gives us a better understanding of 3-Phase AC arc plasma discharge.

Tar evolution in a two stage fluid bed–plasma gasification process for waste valorization

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 C2-species are completely converted to carbon monoxide and hydrogen, and no soot significantly formed. Oxygen atoms initially formed from CO2 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.

Infrastructure Support for Bioenergy Development in Cities

Worldwide, bioenergy production is increasing. However, there is still a lack of understanding of the types of infrastructural modifications necessary to support further bioenergy development in ways that are both cost effective and environmentally sustainable. This paper provides an overview of the infrastructure support crucial for enabling large-scale bioenergy production in cities. Three waste-to-bioenergy pathways to produce biodiesel from waste oils, syngas from plasma gasification of municipal solid waste (MSW), and bioenergy from algae are reviewed. (i) To produce biodiesel from waste oils, a cost-effective feedstock collection system is key as feedstock cost, including transportation cost, is the single largest contributor to total cost. (ii) To promote the production of syngas from MSW by plasma gasification, a decentralized approach is recommended in the near to medium term. This is because at present, there is still little experience operating large MSW plasma gasification plants. A decentralized approach creates opportunities for public-private partnerships, leading to investments to gain operational experience. Soft infrastructure in the form of a well-developed recycling program or legislation is also necessary to ensure the gasification does not compete with recycling for recyclables. (iii) To produce bioenergy from algae, two infrastructures are vital. The first is infrastructure to integrate wastewater treatment and algae cultivation with nutrients and carbon dioxide recycling. The second is infrastructure to create large surface areas from sides of buildings and/or rooftops that are well exposed to sunlight for algae growth. Provided these infrastructures are in place, the three pathways, combined, have the potential to supply up to 12–16 % of Hong Kong’s electricity demand if converting the energy products from the pathways to electricity. Further, the pathways create new interdependencies between the waste and energy sectors. The interdependencies, while synergistic, could lead to new vulnerabilities such that a failure of one sector will cause a failure in the other as well. Care must be taken when designing systems to minimize this.

Synthesis Gas from Waste Plasma Gasification for Fueling Lime Kiln

Synthesis Gas from Waste Plasma Gasification for Fueling Lime Kiln

Application of analytic hierarchy process in a waste treatment technology assessment in Mexico.

The high per capita generation of solid waste and the environmental problems in major rural communities of Ensenada, Baja California, have prompted authorities to seek alternatives for waste treatment. In the absence of a selection methodology, three technologies of waste treatment with energy recovery (an anaerobic digester, a downdraft gasifier, and a plasma gasifier) were evaluated, taking the broader social, political, economic, and environmental issues into considerations. Using the scientific literature as a baseline, interviews with experts, decision makers and the community, and waste stream studies were used to construct a hierarchy that was evaluated by the analytic hierarchy process. In terms of the criteria, judgments, and assumptions made in the model, the anaerobic digester was found to have the highest rating and should consequently be selected as the waste treatment technology for this area. The study results showed low sensitivity, so alternative scenarios were not considered. The methodology developed in this study may be useful for other governments who wish to assess technologies to select waste treatment.

Preparation of glass–ceramic foams from the municipal solid waste slag produced by plasma gasification process

The glass–ceramic foams were prepared using high content of municipal solid waste (MSW) slag (50–70%) generated by plasma gasification process. Calcium carbonate and sodium borate were used as foaming agent and flux agent, respectively. The effects of different sintering temperature on the density, mechanical strength and crystalline phases were discussed. The results showed that the glass–ceramic foams with 70wt% MSW slag sintered at 920°C exhibited an excellent strength-to-density ratio (crushing strength exceeding 2.5MPa, with a density below 0.3g/cm3), due to the precipitation of micro-crystals. The preparation of foams utilizing high content of MSW slag eliminates the problem of its disposal and displays huge commercial interests.

System development and self-sustainability analysis for upgrading human waste to power

This paper presents a system to upgrade faecal matter in an environmentally friendly way by the deployment of plasma gasification and SOFC (solid oxide fuel cells). The entire system chain, including a dryer, a microwave-assisted plasma gasifier, a gas processing system and an SOFC system, is studied to evaluate system performance and self-sustainability. The effects of gas processing approach, moisture content and oxidant-to-fuel ratio on system self-sustainability are studied in detail. The results show that the variables aforementioned strongly affect system performance. It is recommended to deploy the approach of adding air, a mild moisture content (30% by weight) and an intermediate oxidant to fuel ratio (1.05 kg kg−1) to achieve enhanced system performance under the conditions studied.

Применение плазменной газификации древесной биомассы с целью получения синтез-газа для синтеза метанола

Применение плазменной газификации древесной биомассы с целью получения синтез-газа для синтеза метанола

Plasma assisted power coal combustion in the furnace of utility boiler: Numerical modeling and full-scale test

This work presents modern plasma technology for solid fuel ignition and combustion. It promotes more effective and environmentally friendly low-rank coal incineration. To implement this technology at coal fired thermal power plants plasma-fuel systems (PFSs) were developed. PFS is a pulverized coal burner equipped with arc plasmatron producing high temperature air stream of 4000–6000°C. Basis of technology PFS is plasma thermo-chemical preparation of coal for burning. It consists in plasma heating of air–coal mixture up to temperature of coal volatiles release and char carbon partial gasification. In PFS air–coal mixture is deficient in oxygen therefore carbon is oxidized mainly to carbon monoxide. As a result, at the PFS exit a highly reactive mixture is formed of combustible gases and partially burned char particles, together with products of combustion, while the temperature of the mixture is around 1050°C. Further mixing with air promotes intensive ignition and combustion of the prepared in the PFS fuel.PFS have been tested for boilers start up and pulverized coal flame stabilization at 30 power boilers of 75–950t/h steam productivity. The boilers were equipped with different types of pulverized coal burners: direct flow, muffle and swirl burners. At tests of the PFS power coals of all ranks (lignite, bituminous, anthracite and their mixtures) were incinerated. Volatile content of them was in range of 4–50%, ash varied from 15% to 48% and heat of combustion was from 6690 to 25100kJ/kg.To show advantages of the plasma technology of coal combustion before conventional one numerical investigation of plasma ignition, gasification and thermo-chemical preparation of air–coal mixture for incineration in a power boiler was fulfilled. The numerical modeling was performed for low-rank bituminous coal of 40% ash content incinerated at a boiler of 420t/h steam productivity. Both analysis of the numerical modeling and experience of PFS industrial use showed ecological efficiency of the plasma technology. When plasmatrons operate in the regime of plasma stabilization of pulverized coal flame, NOX emission is reduced twice and amount of unburned carbon is reduced four times. The PFSs reduce the temperature at the exit of the furnace. Tests of the PFS for the boiler BKZ-420 of Almaty TPP-2 cold startup confirmed the possibility of high-ash Ekibastuz coal ignition in the cold furnace without heating of primary air.

Hazardous Waste Vitrification by Plasma Gasification Process

Hazardous Wastes Control is one of the major problems of waste management companies and governmentand environment and disposal of such hazardous wastes is critical and problematic. Current method of hazardous waste disposal,which include mass burn or incineration, and landfilling create new problems to the environment. Vitrification of such wastes by thermal plasma gasification process appears to be a solution to hazardous waste disposal that does not create further problems to the environment. The energy generated by plasma arcs has been recently applied to hazardous waste vitrification. The technology involves subjecting waste material to high temperatures with the purpose of immobilizing nonvolatile chemical species into a nonleachable matrix. Plasma arc gasification and vitrification processes are well known for special waste disposal requirements. This paper presents the high tech plasma gasification processas an efficient technological tool for hazardous waste destruction, such as hospital wastes, nuclear wastes, pyrotechnic smoke assemblies, thermal batteries, and other military wastes. Results show that thermal plasma gasification process is effective in hazardous waste vitrification.

Thermal Plasma Solution for Environmental Waste Management and Power Generation

The twin problems of environmental wastes and power shortages in fast growing economies of developing countries are real. The cities are littered with municipal solid waste and other wastes in open dumps dangerous to health and environment. In addition, there is insufficient electricenergy to power the ever expanding cities and industries. One solution to these problems, which will not harm the environment, lies in the use of thermal plasma physics and associated technologies. Application of thermal Plasma to waste treatment isone of the novel methods of waste management and sustainable power generation to meet the needs of developing economies and guarantee safe environment. The thermal plasma process ensures gasification of the carbon-containing materials in the waste to produce synthesis gas (syngas) composed primarily of carbon monoxide and hydrogen, which is used to produce energy through reciprocating engine generators - gas turbines and steam boilers in integrated plasma gasification combine circle (IPGCC). Inorganic components get converted to glassy slag safe for use as a construction aggregate. The double benefits of waste treatment and energy production are realized from this plasma process.The results show the process is environmentally responsible creating a product gas with very low quantities of NOx, SOx, dioxins and furans.Thermal Plasma Processes for waste management and power generation from abundant waste is viable and sustainable. Keyword: Plasma gasification, Environmental Waste, Power generation, Syngas