Wood residues generated from orchard maintenance operations represent a serious disposal problem, as well as a valuable opportunity for the bioenergy sector. However, their widespread use as ...renewable fuel is hindered by uncertainty about crucial quality issues, such as: ash content, ash melting behavior and chemical composition. This paper investigates the main physical and chemical characteristics of pruning residues generated by five of the most common European orchard crops: vine, olive, apple, pear and hazelnut. The results of the analyses are contrasted with the quality specifications set by EU standard UNI EN 14961-1 2010 for forest residues, in the absence of a standard specifically designed for orchard pruning residues. All tested orchard residues biomasses fulfill set specifications, and they also present similar characteristics in terms of ash content, size distribution and heating value. However, the chemical composition of pear and vine residues may raise some concern, due to the high content of nitrogen of the former, and to the high ash, sulfur and chlorine content of the latter. Olive and hazelnut pruning residues seem the most suitable for direct combustion, probably because the origin crops are cultivated less intensively and receive smaller chemical inputs.
•We compared the fuel quality of pruning residues of five agricultural crops.•Quality parameters were contrasted with the EU standard UNI EN 14961-1 2010.•Physical properties of all residues are similar to those of forest residues.•The tested biomasses are suitable for combustion in common wood chip facilities.•High content of N, Cl and heavy metals may require flue gases abatement systems.
Poplar cultivation for wood/timber production has a growth production cycle of about 10–15 years. Usually the stem is separated from the crown and used to produce material of different kind such as ...veneer, pallets, panels, etc. For wood industries, crowns generally represent waste material to be disposed of, causing economic and time losses. It is generally believed that the costs of managing crown biomass are higher than the potential incomes obtainable. Nonetheless, it is worthwhile investigating the possibility of using these byproducts as energy source and evaluating their value as a fuel. However, storing such residues presents several problems connected with spontaneous microbial degradation.
The aim of this work was to evaluate the storage effects on chipped biomass deriving from the crown and stem wood of poplar and how they affect fuel quality and dry matter losses.
A storage trial was carried out with three piles of stem wood chips and three of crown chips coming from a 15 year old poplar plantation. The piles were stored outdoors for six months under the same climatic conditions.
The effect of storage on fuel quality was evaluated with respect to moisture content, gross and net calorific values, chemical composition, ash content, and bulk density.
The variation of temperatures inside each pile due to heat development was continuously monitored and showed different trends between piles depending on source material. Results showed that chips from crown material had better storage properties and exhibited lower decay than chips from stem wood.
•Monitoring the storage behavior of poplar wood chips obtained from crown and stem.•Chemical and physical studies on stored wood chips have been carried out.•Results showed that chips from crown material stored better than chips from stem wood.
•Sulfur content by itself did not influence the microbial growth in diesel fuel during the storage.•Ultraviolet radiation treatment did not cause significant changes in fuel properties.•Under the ...best conditions, the microbial biomass decreased 97%, after 360 min of UV irradiation.•After ultraviolet radiation treatment the microbial growth stayed stable per 10 days.
This work aimed to use ultraviolet (UV) radiation to prevent microbial growth in diesel fuel with different compositions. Commercial samples of ultra-low-sulfur diesel (ULSD) and high-sulfur diesel (HSD) fuels with 11% of biodiesel were used as purchased. These samples were incorporated of 20% biodiesel and different amounts of free water (no addition, 2500, and 10,000 mL.m−3). All samples were stored for ten days and subjected to UV-C radiation treatment (55 W, 253 nm) for 360 min to reduce the number of microorganisms. Physicochemical parameters, such as water content, kinematic viscosity, density, and oxidative stability, were measured before and after UV-C treatment. The presence of microorganisms was detected by UV–vis spectrophotometry (600 nm) during the simulated storage, before and after UV-C treatment. An increase in the number of microorganisms was observed during the storage period due to the water content. The UV-C radiation reduced the microorganisms, especially in samples with high water content. Low sulfur levels did not affect the efficiency of the treatment. Significant variations in kinematic viscosity and oxidative stability were observed after the treatment. The presence of microorganisms was reduced by more than 50% after the incidence of UV-C radiation. Therefore, UV-C radiation is a promising technique for microbiological control in diesel fuel. These effects can last up to ten days after the first incidence of radiation.
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•Hydrothermal treatment of EFB notably reduced slagging-fouling tendency in boiler.•Optimized temp, holding time and biomass/liquid ratio achieved >90% K removal.•Interrelationship of ...3 key HTT variables was derived with quadratic regression.•Additional oil recovery of 221.4 ton/yr can be attained with the proposed HTT scheme.•Concentrate waste stream from HTT to anaerobic digester can increase methanation.
This work aims to solve the slagging and fouling problems in palm empty fruit bunch (EFB) power plant by means of simultaneous fuel quality improvement and enhanced recovery of EFB fiber oil and biogas from leaching liquid. Rapid accumulation of minerals on heat transfer surfaces has caused the EFB power plants frequent shutdowns for maintenance and considerable thermal efficiency loss. Hydrothermal treatment (HTT) of EFB was performed at low range temperatures (Temp) under various holding times (HT) and biomass-to-liquid ratios (B/L) aiming to improve fuel quality. Removal of potassium (K) was experimentally identified as the key indicator to reduce slagging and fouling indexes (SI and FI) of EFB ash. HTT at 120 °C, 120 min, and B/L 50 g/L gave best K removal at 90.7%, leaving only 0.19 wt% in the fuel, although lesser conditions were also effective. A statistically significant quadratic regression model of K removal was constructed to show the interrelationship among these independent variables. Moreover, it was found that oil recovery from EFB could be enhanced by HTT, gaining an estimate of 221.4 ton/yr of additional oil in a mid-size palm oil mill. The HTT leachate with high organic content is also a potential substrate for methane production in an existing anaerobic digester in the mill. At the end, a practical integration of HTT to palm oil mill with EFB power plant was proposed.
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•Desoxygenated palm oil (HDO) was produced in 82% yield using a Ni-Mo catalyst.•HDO was isomerized to i-HDO with Pt/SAPO11 obtaining an isomer yield of 81%.•I-HDO has good cold-flow ...properties but bad flash point and distillation range.•Light hydrocarbons were distilled off to tune flash point and the distillation range.•An optimal blend that met quality standards was formulated (71% i-HDOd and 29% HDO).
Renewable diesel is the best alternative to replace biodiesel due to its improved properties, but like biodiesel, renewable diesel has poor cold-flow properties. The hydroisomerization process improves the pour and cloud points of renewable diesel, but it worsens the cetane number and the flame point, both are regulated by international standards. In this work, desoxygenated palm oil (HDO) was produced in high yield (82wt%) using a sulphided NiMo/Al2O3 catalyst. Then, HDO was hydroisomerized at 50bar and 350°C, under hydrogen, with a Pt/SAPO11 catalyst, obtaining an isomer yield of 81%. TPR and TPO analyses showed that this catalyst can be reversibly reduced/oxidized at 155–160°C, therefore, it was completely reduced at the reaction conditions. Characterization of the isomerized product (i-HDO) showed a beneficial effect on cold-flow properties but an adverse effect on flash point, distillation range and cetane index due to light hydrocarbons formed during hydroisomerization. Light hydrocarbons (<C14, 7vol%) in i-HDO were distilled off at 180°C to tune the flash point and the distillation range. The hydroisomerized and distilled product (i-HDOd) was blended with HDO to determine the required hydroisomerization level to meet the cold-flow regulations. The optimal blend consisted of 71% i-HDOd and 29% HDO and it has a cetane index of 92.4, pour point of 2.8°C, flash point of 82°C, distillation range of 225–321°C and heating value of 47.3MJ/kg.
•Integration of effective technologies was applied for developing biodiesel process.•Simultaneous improvement of biodiesel synthesis and fuel quality were achieved.•Iso-propanol was used as a ...reactive co-solvent.•Biodiesel synthesis under mild reaction conditions were successfully presented.•Optimal operating conditions were determined through response surface methodology.
This work addresses the simple and effective technique to simultaneously improve biodiesel synthesis and fuel quality. The co-solvent technology was applied to fulfill this purpose. Experiments were performed through the transesterification of palm oil and ethanol in a microtube reactor under the supercritical conditions. The iso-propanol was added in the system and played the roles as a source of reactant to produce isopropyl esters and co-solvent to enhance the homogeneity of the mixture. Upon the application of iso-propanol, high yield of biodiesel was attained under the milder conditions than those reported in the literature in terms of reaction temperature, pressure, residence time, and ethanol-to-oil molar ratio. The influence of operating conditions on the %Ester was investigated and optimization of %Ester was carried out via response surface methodology. The improvement of biodiesel quality was achieved particularly the cloud and pour points which were better quality than that of the conventional biodiesel production.
The consumption of forestry biomass for energy uses is a promising alternative to fossil fuels since it provides different environmental, economic and social benefits to the countryside. A ...cost-effective methodology is presented in order to establish the biomass price, consistently with its quality. The methodology commonly used in power plants is based exclusively on its estimated heating value, calculated from reference data and measured moisture content. This work analyses the economic benefits of using more accurate heating values determined from other biomass properties, thus requiring additional analyses. Results show that the biomass ash content is the most significant parameter affecting the heating value (a decrease of 760 kJ/kg has been obtained for an ash content increase of 3.7% with respect to reference fuel). The rest of parameters studied (harvesting season and biomass origin) lead to differences below 575 kJ/kg. Considering the increase in the fuel cost from additional analysis, the methodology based on measuring the higher heating value and the moisture content is the most appropriate technique to optimize the cost-benefit ratio of the plant. This technique is even more cost-effective when the frequency of analysis is reduced and the laboratory is shared with other plants from the same company.
•Different strategies to determine the biomass quality have been compared.•The effect of the biomass origin, ash content (handling) and harvesting season has been analysed.•Variability in the ash content is the main parameter affecting the biomass LHV.•The methodology based on measuring HHV and moisture content is the most suitable.•The higher cost of Methodology 3 suggests the use of a common laboratory.
With respect to the use of densified biomass fuels in fully automatic heating systems for the residential sector a high quality of these fuels is required. Several European countries already have ...implemented standards for such fuels. In other countries such standards are in preparation or planned. Furthermore, in some countries also standards from associations are existing (e.g. from the Austrian Pellets Association). In addition to these national standards, European standards for solid biomass fuels are under development. For producers of densified biomass fuels, especially for pellet producers, it is therefore very important to produce high-quality fuels keeping the limiting values of the standards addressed. However, in this context it has to be considered that as a high fuel quality as is necessary for the combustion of densified biomass fuels in automatic small-scale furnaces is not necessary if these fuels are used in larger industrial furnaces as they are equipped with more sophisticated flue gas cleaning, combustion and process control systems. Two pellet qualities, one for industrial and one for small-scale consumers seem to be more meaningful.
Within the framework of the EU-ALTENER-project “An Integrated European Market for Densified Biomass Fuels (INDEBIF)” a questionnaire survey of European producers of densified biomass fuels was performed. In this connection the possibility was offered to the producers to participate in an analysis programme with their fuels. An overview was obtained of the qualities of densified biomass fuels offered in the European market, covering pellets and briquettes from Austria, Italy, Sweden, Spain, Norway and the Czech Republic.
The parameters analysed were the dimensions of the fuels, the bulk and the particle density, the water and the ash content, the gross and the net calorific value, the abrasion, the content of starch (as an indication for the use of biological binding agents), the concentrations of C, H, N, S, Cl, K as well as of the heavy metals Cd, Pb, Zn, Cr, Cu, As and Hg. These parameters have been chosen following the Austrian, German, Swiss and Swedish standards for densified biomass fuels.
The results showed that a majority of the participating producers produce fuels of high quality. However, wood pellets of some producers show a high abrasion, one of the most important quality parameters for pellets. An increased amount of fines often causes failures in the feeding systems used in the residential heating sector. In order to decrease abrasion, the addition of small amounts of biological binding agents (e.g. maize or rye) is possible. This kind of additive is most common in Austria.
Moreover, some producers obviously use not only chemically untreated raw materials or additives, which increase the content of pollutants. Such fuels cause problems regarding emissions, deposit formation and corrosion. Emission problems are expected due to increased contents of N, Cl, S as well as heavy metals. Increased concentrations of heavy metals additionally contaminate the ash, increased Cl concentrations raise the risk of corrosion. Moreover, an increased content of K has a negative effect on the ash melting behaviour and causes higher aerosol formation, which enhances deposit formation and particulate emissions.
•The biochars were prepared from woody and non-woody biomass by pyrolysis.•The biochars had improved fuel qualities than their parent biomass.•The addition of biomass (biochar) in lignite increased ...reactivities of the blends.•Significant interactions were observed within all the fuel blends.•Limited increase of slagging and fouling for biochar/lignite than biomass/lignite.
In this study, thermal characteristics of raw biomass, corresponding pyrolytic biochars and their blends with lignite were investigated. The results showed that pyrolytic biochars had better fuel qualities than their parent biomass. In comparison to raw biomass, the combustion of the biochars shifted towards higher temperature and occurred at continuous temperature zones. The biochar addition in lignite increased the reactivities of the blends. Obvious interactions were observed between biomass/biochar and lignite and resulted in increased total burnout, shortened combustion time and increased maximum weight loss rate, indicating increased combustion efficiencies than that of lignite combustion alone. Regarding ash-related problems, the tendency to form slagging and fouling increased, when pyrolytic biochars were co-combusted with coal. This present study demonstrated that the pyrolytic biochars were more suitable than raw biomass to be co-combusted with lignite for energy generation in existing coal-fired power plants.
Fatty acid methyl ester derived from renewable lipid feedstock is popularly known as biodiesel, the substitute for petroleum based diesel fuel. The non-food oils such as Jatropha (Jatropha curcas), ...Karanja (Pongamia pinnata), waste cooking oil, by-product of vegetable oil refineries are the cheap feedstock for cost-effective production of biodiesel. Jatropha may be one of the most promoted oilseed crop throughout the world due to higher oil yield, suitable fatty acid composition of the oil, adaptability to diverse agro-climatic condition and low gestation period. The current article discusses the updated research and development initiatives undertaken for the study of chemical composition of Jatropha oil, techniques for synthesis of biodiesel using homogeneous catalyst, heterogeneous catalyst, enzymes (lipases) and non-catalytic supercritical process to obtain Jatropha based biodiesel satisfying ASTM 6751, EN 14214 and IS 15607 specifications.
