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Publisher Summary This chapter discusses the role of catalyst impregnation and solvent type in improving liquefaction efficiencies. In direct coal liquefaction processes, chemical bonds in coal structure are broken down by the combined... more
Publisher Summary This chapter discusses the role of catalyst impregnation and solvent type in improving liquefaction efficiencies. In direct coal liquefaction processes, chemical bonds in coal structure are broken down by the combined action of heat and pressure. A suitable catalyst and a hydrogen donor medium increase the cracking process and the stabilization of the intermediate species thus formed. These species go through several transformations resulting in the production of the hydrocarbons of lower molecular weight. Coal liquefaction produces gaseous hydrocarbons and a complex mixture, which can be separated into three fractions according to their solubility in organic solvents: oils, asphaltenes, and preasphaltenes. Oils are the lighter fraction and the most economically valuable, because they contain products in the range similar to those of gasoline and gas oils. Asphaltenes is the intermediate fraction, which is soluble in toluene. Preasphaltenes is the heaviest fraction. To increase coal liquefaction efficiency, a better contact among reagents is promoted, as this will improve mass transfer and reaction rates. The solvent makes easier the access of reagents into coal structure, which decreases diffusional limitations. Catalyst impregnation into coal structure is done by dissolving the catalyst used in ethanol. Ethanol dissolves zinc chloride (ZnCI 2 ) used as catalyst and combines the effect of creating macropores in coal structure with the formation of active sites through breaking weaker bonds and at the same time impregnates the catalyst into coal structure.
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Studies have been undertaken with the objective of using biomass waste as a reburning fuel which could be introduced to the combustor at different heights. The staging of the secondary air was also implemented as a further measure for... more
Studies have been undertaken with the objective of using biomass waste as a reburning fuel which could be introduced to the combustor at different heights. The staging of the secondary air was also implemented as a further measure for controlling the emissions of NO{sub x} and N{sub 2}O. The biomass waste contains very high volatile content and very small amounts of fuel-N. Upon release, these volatiles are generally released as NH{sub y} compounds rather than HCN or other CN groups. Consequently, the reactions leading to the formation of both N{sub 2}O and NO{sub x} appear to be suppressed and the presence of high levels of hydrocarbon radicals originating from volatiles consequently gives rise to a reduction in NO{sub x} amounts. Experimental results obtained suggest that the N{sub 2}O amounts could be lowered by about 20 to 40% and NO{sub x} values were found to be brought down below 250 ppm. With only coal combustion the levels of NO{sub x} and N{sub 2}O were measured to be abou...
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L'invention porte sur une unite de reduction de polluants (4) dans les gaz d'echappement de moteurs a combustion interne (2), composee d'une chambre de combustion (10) a lit fluidise ; d'une conduite de transfert des gaz... more
L'invention porte sur une unite de reduction de polluants (4) dans les gaz d'echappement de moteurs a combustion interne (2), composee d'une chambre de combustion (10) a lit fluidise ; d'une conduite de transfert des gaz d'echappement (11) appropriee pour adresser a la chambre de combustion a lit fluidise (10) les gaz d'echappement provenant d'un ou plusieurs moteurs a combustion interne (2) ; et d'une conduite d'alimentation en combustible (12) pour la chambre de combustion a lit fluidise (10). Le combustible doit etre approprie pour produire a l'interieur de la chambre de combustion a lit fluidise (10) une quantite de carbone et d'ammoniac appropriee pour reagir avec les oxydes d'azote afin de provoquer une reduction de ceux-ci en azote moleculaire.
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STUDY OF PYROLYSIS PROCESS TO RECYCLE TYRES AND PLASTIC WASTES F Pinto M Miranda I ... et al [5]. The RON value was also determined for some samples using ASTM D ... 30 Pinto, Miranda, Gulyurtlu, Cabrita The plastic waste used in this... more
STUDY OF PYROLYSIS PROCESS TO RECYCLE TYRES AND PLASTIC WASTES F Pinto M Miranda I ... et al [5]. The RON value was also determined for some samples using ASTM D ... 30 Pinto, Miranda, Gulyurtlu, Cabrita The plastic waste used in this study included different ...
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Chemical Technology SeriesThe continuous growth of world population along with incresing needs to improve life quality of societies and their dependence on fuel and other derived petroleum products suggest that the overall energy demand... more
Chemical Technology SeriesThe continuous growth of world population along with incresing needs to improve life quality of societies and their dependence on fuel and other derived petroleum products suggest that the overall energy demand will increase significantly in the future. This chapter focuses the production of liquid fuels by pyrolysis applied to rubber tyre and diffetent plastic wastes as an option for integration in the refining process. The advantage is that pyrolysis of polymeric-base wastes tends to reverse the polymerization process used in the production of polymers at moderate conditions of temperature and pressure. The liquids obtained depend upon the polymeric blend. Products yields could lead to liquids similar to petroleum derived fuels as well as chemical feedstocks suitable to a wide range of industries. Considering that it is innivative the integration of polymeric-base wastes streams in petroleum refineries, a more detailed analysis on issues related to retrofitting will be presented
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Combustion studies of mixtures of forestry biomass and used tyres were undertaken in an atmospheric circulating fluidised bed. The combustor was operated over a temperature range of 700 to 1000 °C.
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Thermolysis of plastic waste may have an important role in dealing with the enormous amounts of plastic waste produced all over the world, by decreasing their negative impact on the environment. This waste may be converted into... more
Thermolysis of plastic waste may have an important role in dealing with the enormous amounts of plastic waste produced all over the world, by decreasing their negative impact on the environment. This waste may be converted into economically valuable hydrocarbons, which can be used both as fuels and as feed stock in the petrochemical industry. End product yields and properties
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The emissions of dioxins could be considerable when fuels with high chlorine content are used, particularly in fluidised beds due to constraints to use temperatures in the range 800–900°C for other considerations. However, mixing of fuels... more
The emissions of dioxins could be considerable when fuels with high chlorine content are used, particularly in fluidised beds due to constraints to use temperatures in the range 800–900°C for other considerations. However, mixing of fuels with different characteristics may lead to a reduction in dioxin emissions. Studies are currently being undertaken at the above-mentioned department in mixing fuels of
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The effect of temperature and of gasification medium was studied, using only air, only steam and mixtures of both as gasification medium, with the aim of optimising co-gasification of coal and wastes. The rise in gasification temperature... more
The effect of temperature and of gasification medium was studied, using only air, only steam and mixtures of both as gasification medium, with the aim of optimising co-gasification of coal and wastes. The rise in gasification temperature promoted hydrocarbons further ...
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A project on co-firing in large-scale power plants burning coal is currently funded by the European Commission. It is called COPOWER. The project involves 10 organisations from 6 countries. The project involves combustion studies over the... more
A project on co-firing in large-scale power plants burning coal is currently funded by the European Commission. It is called COPOWER. The project involves 10 organisations from 6 countries. The project involves combustion studies over the full spectrum of equipment size, ranging from small laboratory-scale reactors and pilot plants, to investigate fundamentals and operating parameters, to proving trials on a commercial power plant in Duisburg. The power plant uses a circulating fluidized bed boiler. The results to be obtained are to be compared as function of scale-up. There are two different coals, 3 types of biomass and 2 kinds of waste materials are to be used for blending with coal for co-firing tests. The baseline values are obtained during a campaign of one month at the power station and the results are used for comparison with those to be obtained in other units of various sizes. Future tests will be implemented with the objective to achieve improvement on baseline values. Th...
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The chemistry of nitrous oxide (N{sub 2}O) formation and subsequent decomposition during coal combustion in a FBC still continues to be investigated although a lot of progress has been achieved in recent years. This paper discusses the... more
The chemistry of nitrous oxide (N{sub 2}O) formation and subsequent decomposition during coal combustion in a FBC still continues to be investigated although a lot of progress has been achieved in recent years. This paper discusses the results of experimental work undertaken to investigate the combustion of volatiles released during the fluidized bed combustion of coals. The combustion of volatiles was investigated in a separate combustor following the devolatilization of coal particles in a fluidized bed under the same heating conditions as in combustion. The levels of NO and N{sub 2}O were determined and were compared with those obtained from burning of parent coals and chars produced during the devolatilization. The analysis of the main nitrogen species released into the gas phase, HCN and NH{sub 3} was carried out. The results confirm that HCN is the main precursor responsible for the formation of N{sub 2}O. It was found that the main source of both N{sub 2}O and NO is the combu...
Research Interests: Chemistry and Combustion
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Co-gasification of bagasse wastes mixed with coal is technically feasible, without major installation changes. The effect of experimental conditions on co-gasification process was analysed, to enhance gas production and improve its... more
Co-gasification of bagasse wastes mixed with coal is technically feasible, without major installation changes. The effect of experimental conditions on co-gasification process was analysed, to enhance gas production and improve its composition and energetic content. The rise of bagasse ...
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It was found a strong correlation between PCDD/F formation and the sulphur and chlorine content. Our results point to an interesting empirical model which should be further tested with more experimental data. Additionally, the attained... more
It was found a strong correlation between PCDD/F formation and the sulphur and chlorine content. Our results point to an interesting empirical model which should be further tested with more experimental data. Additionally, the attained mathematical model can be used to adjust fuel mixtures with appropriate sulphur and chlorine input in order to maintain PCDD/F emissions below the legal limits.
Os combustíveis fósseis são responsáveis pelo fornecimento de três quartos da energia consumida no mundo. Importantes desenvolvimentos têm sido e continuam a ser feitos na área da conversão termoquímica de combustíveis visando a produção... more
Os combustíveis fósseis são responsáveis pelo fornecimento de três quartos da energia consumida no mundo. Importantes desenvolvimentos têm sido e continuam a ser feitos na área da conversão termoquímica de combustíveis visando a produção e fornecimento seguro de energia a preços acessíveis e com reduzido teor de emissões para a atmosfera. Assim, a procura de materiais capazes de serem usados a temperaturas cada vez mais elevadas tem crescido continuamente nas últimas décadas. Neste trabalho é efectuada uma síntese sobre o estado da arte dos materiais mais usados no fabrico de equipamento destinado à produção de energia através de tecnologias associadas aos processos de conversão termoquímica (combustão, nomeadamente em leito fluidizado, gaseificação, liquefacção e pirólise) de diversos combustíveis. Para determinação da adequabilidade dos materiais no que diz respeito quer à sua resistência à corrosão, quer às suas propriedades termomecânicas, é feita a correlação das característica...
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Since 1990, by the order of the Joint-Stock Company “GAZPROM” the Research-Engineering Center “Ceramic Heat Engines” has been involved in the development of the stationary ceramic gas-turbine engine (CGTE) of 2.5 MW, efficiency 42% which... more
Since 1990, by the order of the Joint-Stock Company “GAZPROM” the Research-Engineering Center “Ceramic Heat Engines” has been involved in the development of the stationary ceramic gas-turbine engine (CGTE) of 2.5 MW, efficiency 42% which is notably in excess of the characteristics of the serial-production engines of the similar power. Alongside the application of the ceramic materials, a goal to increase the fire and explosion safety of CGTE through use of journal and thrust oil beatings was set up. The refinement of the embodied design of the CGTE gas-static bearings was carried out on specially designed test beds, initially on simplified and then on baseline test beds. On all stages, the rotors were “rigid”, the balancing accuracy ensured the residual imbalance not exceeding 5–7 g*mm, the air cleaning provided the moisture separation of at least 90% with the filtration being not worse than 80μm. The tests were carried out by two stages: initially the journal beatings without the a...
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Page 1. NH3 ABATEMENT IN FLUIDIZED BED CO-GASIFICATION OF RDF AND COAL I. Gulyurtlu, Filomena Pinto, Mario Dias, Helena Lopes, Rui Neto Andre, I. Cabrita INETI-DEECA, Est. Paco do Lumiar, 22, 1649-038 Lisboa, Portugal ...
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Over the last 10 years, the airline industry has come under increasing pressure to reduce operating costs and provide an improved service in an environment of declining revenues. As a result, operators expect engine suppliers to provide... more
Over the last 10 years, the airline industry has come under increasing pressure to reduce operating costs and provide an improved service in an environment of declining revenues. As a result, operators expect engine suppliers to provide more efficient and reliable products and services, with lower and more predictable operating costs. In particular, the creation of long term service agreement offerings such as Rolls-Royce TotalCare™ align the goals of the Original Equipment Manufacturer (OEM) and the operator in ensuring that engines keep flying with minimal disruption at minimised cost. Whilst great strides can be made to optimise cost of ownership around existing products the real potential for quantum reductions comes when the product and service are designed in harmony. This requires a cultural shift from ‘offering a Service around an existing Product’ to ‘designing a Service and the Product that supports it’. In 2002 a programme was launched within Rolls-Royce plc to create and deploy an improved process for ensuring our new products are truly ‘Designed for Service’. This has encompassed a cultural change programme, working practice and process changes, enhanced tools and technique development and embodiment of control systems within the design change process gates. The Trent 1000 engine for the Boeing 787 is the first Rolls-Royce new product to have fully deployed ‘Design for Service’ from its earliest stages of preliminary design. The process has already driven both architectural and detailed design change. This attention to detail from the earliest stages of design is fully expected to ensure that the Trent 1000 is the lowest cost of ownership solution for the Boeing 787 aircraft. This paper discusses the elements of the process, including some of the problems and successes experienced during this initial application.
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ABSTRACT The objective of this work was to demonstrate the feasibility and the environmental performance of FBC technology to burn a fluff fraction of an ASR from a Portuguese vehicle dismantling plant. The combustion studies were carried... more
ABSTRACT The objective of this work was to demonstrate the feasibility and the environmental performance of FBC technology to burn a fluff fraction of an ASR from a Portuguese vehicle dismantling plant. The combustion studies were carried out on the pilot installation of INETI. The results obtained suggest that the Portuguese ASR has a very high mineral content (70%) and the combustion had to be sustained with the use of an auxiliary fuel (propane); the combustion efficiency was very high; the gaseous pollutants could easily be controlled below the permitted limits and sulphur and chlorine emissions were low. ASR could give rise to some fluidizing problems due to the accumulation of ashes in the bed, therefore, it is essential that a more efficient metal separation method to be used during dismantling process; there was an enrichment of heavy metals (Pb, Cu, Mn and Zn) on ashes retained in the cyclones, specially in the smaller particle size range (less then 10 μm); however the ashes did not have tendency for leaching.
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Abstract It is predictable that energy demand will greatly increase in years to come, due to the continuous growth of world population, together with the quest to improve living standards. CO2 emissions are hence expected to increase... more
Abstract It is predictable that energy demand will greatly increase in years to come, due to the continuous growth of world population, together with the quest to improve living standards. CO2 emissions are hence expected to increase signifi-cantly. Gasification is a mature ...
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Research Interests: Environmental Engineering, Carbon, Coal, Waste Management, Environmental Risk, and 14 moreOperational Risk, Heavy metals, Biomass combustion, Incineration, Heavy Metal, Polycyclic aromatic hydrocarbons (PAHs), Pinus, Gases, Landfill Leachate Management and Characterization, Hazardous Substances, Fluidized Bed Combustion, Biomass Ashes, Coal ash, and Thermo Gravimetric Analysis
This paper presents the results of the study of a combustible fraction of automotive shredder residues (CASRs) and the corresponding ashes generated by combustion on a fluidized bed pilot with the aim to understand the influence of... more
This paper presents the results of the study of a combustible fraction of automotive shredder residues (CASRs) and the corresponding ashes generated by combustion on a fluidized bed pilot with the aim to understand the influence of thermal treatment regarding properties for final disposal, such as landfilling. The chemical composition was evaluated and the leachability behaviour of ashes and CASR was investigated using the three more commonly used tests: the European Standard EN 12457, the US TCLP-EPA 1311 and the Dutch availability test EA NEN 7371. Different results were obtained depending on the specific conditions of the methods employed. It was found that both the CASR and the ashes contained large amounts of toxic metals and other undesirable elements, such as Cl and S. For the CASR, in addition to the leachability of organic matter above the limit set for hazardous materials, the release of heavy metals, either under alkaline and acidic conditions was significant, revealing the serious risks associated to the landfilling practices still being undertaken worldwide. Release of organic matter from ashes was insignificant, but solubility of sulphates increased and chlorides exceed the hazardous limits in the case of fly ashes. Toxic metals were found to leach from the ashes only under acidic conditions, except Pb and Cu which also leached from finer ashes at alkaline pH. Cr also leached from ashes at alkaline pH values. Both the Dutch availability and TCLP revealed much higher leaching intensities than the European Standard due to the acidity of leachants. However, it was found that ashes may be more resistant to acidification because they exhibit much higher acid neutralization capacity (ANC) than the untreated CASR. The study undertaken shows that thermal valorisation of the combustible fraction of ASR may avoid the risks associated with their landfilling; however, care has to be taken with the ashes because they also behave as hazardous residues. Although, the mass reduction provided by thermal treatment may make landfilling less expensive, a more profitable reutilization of the ashes should be developed.
Research Interests: Environmental Engineering, Carbon, Combustion, Heat Treatment, Automobiles, and 15 moreIncineration, Heavy Metal, Lead, Profitability, Fly Ash, Acidification, Fluidized Bed, Particulate Matter, Chemical Composition, Organic Matter, Acid Neutralizing Capacity, Neutralisation, Hazardous Substances, Neutralization, and Coal ash
Research Interests: Analytical Chemistry, Calibration, Solid Phase Microextraction, Polycyclic aromatic hydrocarbons (PAHs), Enrichment factor, and 12 moreGas Chromatography/mass Spectrometry, Reproducibility of Results, Water soluble polymers, Benzene, Correlation coefficient, Sampling Technique, Method Validation, Toluene, Aromatic Hydrocarbon, Xylenes, Relative Standard Deviation, and limit of detection
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The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal... more
The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal treatment have not been fully studied. Two combustion tests were performed in a fluidized bed combustor. Colombian coal was used as fuel in test A. A blend (1+1) of this coal and a stabilized SS (Biogran) was used in a second test B. Samples of the bottom and fly ashes trapped in two sequential cyclones were collected. The characterization of the ashes was focused on two main aspects: (1) the bulk content of a set of metals and (2) the characterization of eluates produced according to the European Standard leaching test EN 12457-2. The eluates were submitted to an ecotoxicological characterization for two bio-indicators. In what concerns the bulk content of ashes, both combustion tests have produced ashes with different compositions. The ashes formed during the co-combustion test have shown higher concentrations of metals, namely Cr, Cu, Ni, Pb, Zn and Fe for all ashes. The leaching test has shown low mobility of these elements from the by-products produced during the combustion and co-combustion tests. Cr and Cr(VI) were mainly detected in the eluates of the 1st cyclone ashes produced in both combustion tests and in the 2nd cyclone ashes produced in the co-combustion test. Considering the ecotoxicity assays, the eluates of bottom and fly ashes for both combustion and co-combustion tests have shown low ecotoxic levels. The micro-crustacean Daphnia magna was generally more sensitive than the bacterium Vibrio fischeri. CEMWE criterion has allowed to classify the bottom ashes for both combustion and co-combustion tests as non-toxic residues and the fly ashes collected in both cyclones as toxic.
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The combustion behavior of municipal solid waste was studied in a pilot fluidized bed combustor. The waste was pelletized prior to its use. Both co-firing with coal and combustion of waste alone were under taken. The combustion studies... more
The combustion behavior of municipal solid waste was studied in a pilot fluidized bed combustor. The waste was pelletized prior to its use. Both co-firing with coal and combustion of waste alone were under taken. The combustion studies were carried out on the pilot installation of INETI. The fluidized bed combustor is square in cross section with each side being 300mm long. Its height is 5000mm. There is a second air supply to the freeboard at different heights to deal with high volatile fuels. There was a continuous monitoring of the temperatures in the bed, as well as the composition of the combustion gases. The combustion gases leaving the reactor were let go through the recycling cyclone first to capture most of particulates elutriated out of the combustor. There was a second cyclone, which was employed with the aim of increasing the overall efficiency of collecting solid particles. The gaseous pollutants leaving the stack were sampled under isokinetic conditions for particulate...
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A mixture involving wood, plastics, paper, and textile materials was burned in a fluidized bed combustor to monitor the gaseous emissions and to analyze the ashes collected in different locations of the installation. The ashes collected... more
A mixture involving wood, plastics, paper, and textile materials was burned in a fluidized bed combustor to monitor the gaseous emissions and to analyze the ashes collected in different locations of the installation. The ashes collected were first analyzed to verify the partitioning of heavy metals in different ash streams. They were then subjected to leaching tests to verify the solubility of different components present. There is a growing interest in utilizing wastes, which cannot be recycled for further use, for energy, particularly in Europe as the amounts are great and the cost of depositing them in landfills has become very considerable. These wastes are considered renewable sources and the recent policy is to encourage their use for energy, especially for decentralized energy production. However, these wastes may be contaminated and have to be verified that their utilization for energy does not bring about any adverse consequences on the environment. Each component making up...
The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from... more
The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals (HM). Heavy metals were collected and analyzed from different locations of the installation, which included the stack, the two cyclones, and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the m...