Papers by Ibrahim Gulyurtlu
In spite of its natural sources, Turkey depends on other countries in terms of energy production,... more In spite of its natural sources, Turkey depends on other countries in terms of energy production, and a transfer from conventional fossil sources to sustainable energy sources is strongly necessary. Among the sustainable energy sources, biomass is the subject of this study. The characteristics, logistic aspects, environmental aspects, economical, legal and technical aspects are investigated in order to show that the possible biomass co-firing is very important for the construction of economic, sustainable and environmentally friendly energy systems. r
Renewable and Sustainable Energy Reviews, 2007
In spite of its natural sources, Turkey depends on other countries in terms of energy production,... more In spite of its natural sources, Turkey depends on other countries in terms of energy production, and a transfer from conventional fossil sources to sustainable energy sources is strongly necessary. Among the sustainable energy sources, biomass is the subject of this study. The characteristics, logistic aspects, environmental aspects, economical, legal and technical aspects are investigated in order to show that the possible biomass co-firing is very important for the construction of economic, sustainable and environmentally friendly energy systems. r
Page 1. CO 2 and NO x Emissions Reduction in Combustion Systems Isabel Cabrita, PedroAzevedo &... more Page 1. CO 2 and NO x Emissions Reduction in Combustion Systems Isabel Cabrita, PedroAzevedo & Ibrahim Gulyurtlu INTERNATIONAL WORKSHOP Energy Optimization in Industry and the Reduction of CO 2 Emissions Page 2. Contents Fuels and Combustion ...
The use of biomass fuels for energy production through combustion has a growing application world... more The use of biomass fuels for energy production through combustion has a growing application worldwide mainly for two reasons: first, the utilization of biomass for energy contributes to mitigate emission of green house gases; second, its use decreases the dependence of imported fossil fuels in Europe. The objective of this work was to study the combustion behaviour of two endogenous biomass species: cardoon (cynara cardunculus) and arundo (arundo donax), which were specially produced in energy crops plantations. Mixtures of cardoon and a forestry biomass specie (eucalyptus) were also studied to evaluate potential benefits from synergies between both biomass fuel types. The results showed that the utilization of cardoon, in pelletized form, and loose arundo as feedstock, did not give rise to any operational problems related with the feeding system. It was verified that the mono combustion of cardoon could pose problems at industrial scale in fluidised bed systems, considering the high levels of HCl and NO X emissions obtained and tendency to sinter the bed sand material. The addition of the forestry biomass to cardoon appeared to prevent the bed agglomeration problem. Furthermore, both the NO X and SO 2 emissions were found to decrease at the same time suggesting potential synergy of blending different types of biomass regarding pollutant emissions and in bed agglomeration problems.
Fuel, Sep 1, 2010
Thermal degradation was studied as a method to decompose mixtures of rubber tyre (RT) and differe... more Thermal degradation was studied as a method to decompose mixtures of rubber tyre (RT) and different plastic wastes (PE, PP and PS) with the aim of producing a liquid fuel [1], as well as valuable chemical raw materials. An experimental set of runs was performed to establish the operational conditions that maximize liquid fraction production in a 1 litre batch reactor. Waste blends used were composed of 30% w/w RT and 70% w/w plastics (20% PE, 30% PP and 20% w/w PS). The complex hydrocarbon liquid mixture obtained during pyrolysis of these residues was highly dependent on experimental parameters, namely temperature, initial pressure and reaction time, which are the three most important factors affecting liquid yields. Regression analyses of experimental data were performed according to response surface methodology (RSM). As a result, experimental conditions optimized based on Factorial Design Methodology were 370°C, 0.48 MPa for initial pressure and 15 min for reaction time. In order to validate the results obtained by the RSM model, three extra runs were conducted sequentially and average values were calculated and found to be: gas yield of 4.9% w/w, liquid yield of 81.3% w/w and solid yield of 12.7% w/w with an experimental deviation of 0.95%. Ó
Waste Management, Feb 1, 2009
This paper presents the results of the study of a combustible fraction of automotive shredder res... 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.
Fuel, Dec 1, 2009
Coal mixed with different types of wastes was co-gasified in a pilot-scale installation. The syng... more Coal mixed with different types of wastes was co-gasified in a pilot-scale installation. The syngas produced was hot treated in two catalytic fixed-bed reactors. In the first one, dolomite was used and in the second reactor, a nickel-based catalyst was employed. Two different grade coals were tested, Puertollano and Colombian. Puertollano coal had high ash and sulphur contents, 42.5% and 2.4%, respectively, while ash and sulphur contents of Colombian coal were, respectively, 12.7% and 0.9%. Pine, bagasse, RDF and PE were the wastes mixed with both coals. After dolomite fixed-bed reactor, H 2 S and NH 3 contents in syngas were much lower than those of the gas leaving the gasifier. For most coal and waste blends, NH 3 reductions changed between 30% and 50% depending on feedstock nitrogen content, while H 2 S reductions achieved values from 68% to 74%, also depending on H 2 S concentration in syngas. After syngas had gone through the nickel-based catalyst, it presented H 2 S and NH 3 contents that allowed its use in boilers and gas engines for most coal and waste blends. The overall syngas treatment led to H 2 S and NH 3 reductions higher than 97%. For most experiments, final H 2 S and NH 3 concentration in syngas were below 20 ppmv and 30 ppmv, respectively.
Oxy-gasification may play an important role in controlling and decreasing CO 2 emissions. Gasific... more Oxy-gasification may play an important role in controlling and decreasing CO 2 emissions. Gasification is a possible option to achieve carbon capture from the fuel before combustion and to produce a hydrogen rich fuel and a CO 2 stream for storage. To achieve these goals it is fundamental to use oxygen instead of air during gasification to avoid the dilution effect of nitrogen and to simplify the separation process of a CO 2 stream. Oxy-gasification leads to the production of a syngas, whose main components are: CO, CO 2 , H 2 and CH 4 . After syngas cleaning processes to remove particulates, tar, NH 3 , H 2 S and HCl, the water gas-shift reaction converts CO into CO 2 , thus the final syngas main components are only H 2 and CO 2 , which simplifies CO 2 capture. However, the production of oxygen increases the overall cost of gasification process and may be a drawback of the process. This paper compares the performance of a pilot scale gasification installation when air or oxygen is used as gasification medium.
J Anal Appl Pyrol, 1999
Thermolysis of plastic waste may have an important role in dealing with the enormous amounts of p... 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
The need to substitute fossil fuel feedstocks with endogeneous biomass to produce energy with low... more The need to substitute fossil fuel feedstocks with endogeneous biomass to produce energy with lower environmental impact makes necessary to develop innovative and technologically more advanced processes for energy production. Gasification of Cynara cardunculus L. (cardoon) alone and mixed with Eucalyptus was carried out in a bench scale fluidized bed gasifier to study the influence of operating parameters that could lead to a gas rich in hydrogen. The gasification tests were carried out using a mixture of oxygen and steam, as gasifying agent, to avoid the dilution effect of nitrogen that exists in air. The effect of catalysts addition to the bed on gas composition was analyzed as well as the influence in the level of contaminants like H 2 S, HCl, NH 3 and tars in the gas produced. Steam and temperature had a positive effect by promoting the hydrogen production. The higher heating value of the gas produced was determined to be in the range 12 -15 kJ/nm 3 in a dry-nitrogen-free basis. Cardoon contains N, S and Cl which may give rise to problems during the gasification process and to the eventual use of the syngas produced. The results obtained showed that the presence of contaminants could be decreased through retention in the solid phase and by employing a condensation system to separate out pollutants in the liquid phase. This paper will fully present and discuss the results obtained with the gasification of cynara cardunculus and eucalyptus in a fluidized bed gasifier.
Since the nineties, environmental and economic problems, like the necessity to decrease greenhous... more Since the nineties, environmental and economic problems, like the necessity to decrease greenhouse gas emissions encouraged the use of renewable energy sources. Directive 2001/77/CE relative to the promotion of electricity produced from renewable energy has set targets to the share of renewables in the energy consumption that are being reviewed in light of the growing concerns with the climate change evidences. However, coal still contributes to nearly 40% of worldwide electricity generation and will maintain an important role in the global energy supply. As a way to contribute to those targets and maintain competiveness in the energy market, co-combustion of biomass with coal in existing installations is being promoted, allowing the use of biomass without major needs for retrofitting. However uncertainty in supply of high quality biomass, like wood, has led to the use of residual biomass or agricultural biomass. Their properties and composition are highly variable and differ from coals, hence creating problems. For this reason, the behaviour of ashes during combustion is a challenge for trouble free use of biomass for energy. Efforts to overcome these problems include the investigations of several aspects, as for example the type of associations of problematic elements in the fuels that may be responsible for ash related problems such has slagging and fouling. The goal of this paper is to correlate the elements bound in biomass fuels with the partition of elements and their relative enrichment in the several ash streams produced by combustion and co-combustion tests of biomass with coal to verify to which degree the reactivity of the elements may dictate their behaviour during combustion. The chemical fractionating methodology applied to the fuels was based in previous studies developed by Zevenhoven and consists in consecutive use of three increasingly strong solvents; pure water (H 2 O), 1M ammonium acetate (NH 4 Ac) and 1M HCl. The chemical fractionating was performed in duplicate and based on duplicate precision, instrumental precision and trueness; the uncertainties of the results were estimated. Combustion and co-combustion tests (with 5, 15 and 25 %wt of biomass) were carried out on a pilot scale fluidized bed combustor (FBC). Two different coals were used and three types of biomass; wood pellets, straw pellets and olive bagasse were tested. The four ash steams obtained; bottom ash, first and second cyclone ash and stack flay ash were studied. Uncertainty of analysis was estimated based in the duplicate precision and the trueness was evaluated thought interlaboratorial tests performance conducted, which allowed to establish the elemental mass balances of the combustion system and the partitioning of elements through the ash streams. The relative enrichment of elements in the several ash streams was estimated, incorporating uncertainties for a better assessment of the influence of elements reactivity on ash behaviour.
Energy Fuels, 2008
This work was undertaken with the aim of quantifing the relative amounts of NH 3 and HCN released... more This work was undertaken with the aim of quantifing the relative amounts of NH 3 and HCN released from different residues, which included sewage sludge, refuse derived fuel (RDF), and sawdust, during their devolatilization under fluidized bed conditions. The results were compared with data collected for bituminous coals of different origin (USA, South Africa, Colombia, and UK). The relation between amounts of HCN and NH 3 released and the levels of NO X and N 2 O formed during cocombustion was also addressed. The partitioning of nitrogen between volatiles and char was also quantified. The pyrolysis studies were undertaken in a small fluidized bed reactor of 80 mm of ID and 500 mm high using an inert atmosphere (N 2 ). The HCN and NH 3 were quantified by bubbling the pyrolysis gases in absorbing solutions which were subsequently analyzed with selective electrodes. The combustion studies were carried out on a pilot installation. The fluidized bed combustor is square in cross section with each side being 300 mm long. There is secondary air supply to the freeboard at different heights to deal with high volatile fuels as almost all waste materials are. The temperatures in the bed and in the freeboard and that of the flue gases leaving the reactor were continuously monitored. The results obtained suggest that, while coal releases nitrogen mostly as HCN, residues like RDF and sewage sludge give out fuel-N in greater quantities as NH 3 . Residues at fluidized bed combustion (FBC) temperatures release more than 80% of the fuel-N with the volatiles. The NH 3 evolved during pyrolysis acted as a reducing agent on NO X emissions. The presence of calcium significantly reduces the emission of N 2 O probably by interfering with HCN chemistry. With high amounts of residues in the fuel mixture, the relative importance of char on the nitrogen chemistry substantially decreases. By using cocombustion, it is possible to reduce fuel-N conversion to NO X and N 2 O, by tuning the amounts of coal and residue in the mixture.
Industrial Engineering Chemistry Research, 2004
This paper presents a study of pollutant emissions during combustion tests of sewage sludge in a ... more This paper presents a study of pollutant emissions during combustion tests of sewage sludge in a pilot fluidized-bed system. Mono-combustion of sludge and its co-combustion with coal were compared with combustion of coal alone. It was verified that the high N ...
Char residues produced in co-pyrolysis of different wastes were characterized through chemical an... more Char residues produced in co-pyrolysis of different wastes were characterized through chemical and toxicity tests. A fraction of the solid chars was treated by extraction with dichloromethane. Different volatility fractions present in the extracted and non extracted char were evaluated. A selected group of heavy metals was determined in both chars. Chars were subjected to the leaching test ISO/TS 21268 -2 and the resulting eluates were further characterized by determining a group of inorganic parameters and the concentrations of several organic contaminants. An ecotoxicological characterization was performed by using the bio-indicator Vibrio fischeri. The chemical and ecotoxicological characterization led to a classification of the chars as ecotoxic materials.
Fuel, Nov 1, 2010
Coal mixed with different types of wastes was co-gasified in a pilot-scale installation. The syng... more Coal mixed with different types of wastes was co-gasified in a pilot-scale installation. The syngas produced was hot treated in two catalytic fixed-bed reactors. In the first one, dolomite was used and in the second reactor, a nickel-based catalyst was employed. Two different grade coals were tested, Puertollano and Colombian. Puertollano coal had high ash and sulphur contents, 42.5% and 2.4%, respectively, while ash and sulphur contents of Colombian coal were, respectively, 12.7% and 0.9%. Pine, bagasse, RDF and PE were the wastes mixed with both coals. After dolomite fixed-bed reactor, H 2 S and NH 3 contents in syngas were much lower than those of the gas leaving the gasifier. For most coal and waste blends, NH 3 reductions changed between 30% and 50% depending on feedstock nitrogen content, while H 2 S reductions achieved values from 68% to 74%, also depending on H 2 S concentration in syngas. After syngas had gone through the nickel-based catalyst, it presented H 2 S and NH 3 contents that allowed its use in boilers and gas engines for most coal and waste blends. The overall syngas treatment led to H 2 S and NH 3 reductions higher than 97%. For most experiments, final H 2 S and NH 3 concentration in syngas were below 20 ppmv and 30 ppmv, respectively.
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Papers by Ibrahim Gulyurtlu