Biofuel Quality Research Articles

Effect of different ash/organics and C/H/O ratios on characteristics and reaction mechanisms of sludge microwave pyrolysis to generate bio-fuels

To study the effects of different ash/organics and C/H/O ratios on bio-fuel characteristics and energy efficiency, four kinds of sludge with different properties were used for microwave pyrolysis (800 °C). Moreover, the microwave pyrolysis reaction mechanisms of different sludge were also explored. The results showed that high-ash sludge could accelerate the frequency of polar molecule rotation in the microwave field due to the presence of oxides with dielectric properties in ash, thereby achieving faster heating rates and higher temperatures. However, compared with high-organic sludge, high-ash sludge exhibited lower bio-gas yield and higher bio-char yield. As the H/C ratio increased from 0.127 to 0.148, the bio-gas yield increased from 15.41% to 40.01%, and the content of H2 in bio-gas and aliphatics in bio-oil increased to 36.69 vol% and 26.54 wt%, respectively. When the O/C ratio was reduced to 1.31, the content of CO and oxygenated compound in bio-oil increased to 31.25 vol% and 40.04 wt%, which lowered the quality of the bio-oil. Those consequences also determined that a mixture of sludge with different ash/organic ratios could be pyrolyzed to obtain high-quality bio-fuels and high energy efficiency. Differences in C/H/O ratios in the mixed sludge greatly affected the microwave pyrolysis heating process, which affected the pyrolysis reactions and the quality of the bio-fuels. Therefore, this study provides a theoretical basis to elevate the quality of bio-fuels and reduce microwave pyrolysis costs.

Blends of charcoal fines and wood improve the combustibility and quality of the solid biofuels

The effects of the blends of charcoal fines and Schizolobium parahyba var. amazonicum (parica) wood on the briquette quality and on the combustibility of this solid biofuel is not fully understood, especially from fast-growing plantations with Amazonian tree species. In addition, this paper presents new information about the occurrence of inorganic elements that may contribute to increase the emission of toxic compounds in the combustion of parica wood, for example, Cl. Thus, this study evaluated the composition of charcoal and S. parahyba var. amazonicum wood for briquettes, investigating the occurrence of inorganic elements responsible for the toxic organochlorine contaminants. Different formulations between charcoal and S. parahyba var. amazonicum wood were analyzed and later compacted in a laboratory briquetting machine with temperature of 90 °C and pressure of 5 MPa. The chemical and elemental composition of S. parahyba var. amazonicum wood was determined using X-ray fluorescence spectrometry (μ-XRF). The briquettes produced were tested for bulk and energy densities, proximate composition, heating value, equilibrium moisture, and resistance to diametral compression. S. parahyba var. amazonicum wood had chlorine levels below the recommended by international standards for solid biofuel intended for non-industrial use (< 300 mg kg−1). S. parahyba var. amazonicum, despite being a fast-growing species, has ideal chemical characteristics for energy purposes (Cl, S, and ashes). The most suitable briquettes were those produced with 50% of charcoal and 50% of S. parahyba var. amazonicum wood. This solid biofuel showed higher heating value of 22.74 MJ kg−1 and ash content of 2.65% db.

Effects of Process Parameters on Sulfur Migration and H2S Generation during Supercritical Water Gasification of Sludge

The generation of sulfur-containing pollution products affects the quality of biofuels obtained from the supercritical water gasification (SCWG) of sludge. This study investigates the effects of the gasification temperature, moisture content, and reaction atmosphere on the evolution of sulfur-containing compounds. The results showed that temperature was the key parameter causing the migration of sulfur from sludge to biogas and liquid products. The sludge decomposition reaction was dominated by ionic reactions at 360 °C, while the decomposition of organic matter was converted to free radical reactions as the temperature increased from 380 °C to 440 °C. The mercaptan and thioether contents of the bio-oil decreased to 0.3% at 440 °C. Correspondingly, the concentration of H2S increased from 6.7 ppm to 38.0 ppm. The decomposition of organic sulfur with an unstable structure (S-H bond and S-C bond) was the main cause of the increase in the content of H2S. Additionally, the solubility and oxidation properties of supercritical water were extremely strong. Some sulfur-containing organic compounds were converted into SO42- via hydrolysis and oxidation reactions, forming sulfate crystals with heavy metals in the bio-char, which aided in achieving the synergistic immobilization of sulfur and heavy metals.

Investigation on woodchip quality with respect to ISO standards and relationship among quality parameters

Considering the ambitious European targets for reducing greenhouse gas emissions the energy production from renewable energy sources is increasing as well as the number of biomass power plants. Biomass is a valid alternative to fossil fuels because it is present worldwide and in different forms. Of course, it is important to assess its quality not only for energy characteristics but also for environmental and operational aspects. In this study more than 1700 woodchip samples have been collected in several Italian power plants and the most important physical and chemical parameters have been analyzed to investigate their quality. These data have been compared with the specification expressed in the recently published ISO/TS 17225-9 technical standard. The results show that the ash content is a fundamental and representative parameter for assessing the biofuel quality and that a certain amount of samples has low quality mainly because of their high ash content. In addition, ANOVA results demonstrated that the quality classes expressed in the standard up to 7% ash content are essential in order to meet the needs of the Italian woodchip market. Beyond the value of 7% in ash content, chlorine, sulfur and nitrogen contents increase significantly with consequences for technical and environmental aspects.

Harnessing the potential of common water hyacinth as an industrial raw material for the production of quality biofuel briquettes

Eichhornia crassipes has a high cellulose and hemicellulose content, which are easily converted to simple sugars, thus making the plant suitable for the production of biofuel briquettes. The main purpose of this proposed work, therefore, was to investigate the production of bio briquettes from E. crassipes. The plant was harvested from a wastewater effluent management system, chopped, sun-dried and pulverized to a particle size of < 5 mm and mixed with various binders (Eucalyptus globulus leaves powder, molasses and phytoplankton scum). The binders were appropriately prepared and added to E. crassipes at the ratios of 10%, 20% and 30%. The quality of biofuel briquettes was evaluated using compressed density, relaxed density, water resistance, durability and calorific values (CV) parameters and compared to those of charcoal briquettes already on the market. The results showed a water resistance capacity of 45%, relaxation ratios of between 1.08 and 1.33, CV of 1148.35 kJ/kg for 20% molasses-based briquettes, CV of 1090.43 kJ/kg for 20% E. globulus leaf-based briquettes and CV of 1422.97 kJ/kg for charcoal-based briquettes. In conclusion, therefore, E. crassipes may become a viable raw material for producing quality biofuel briquettes that are durable with the desired calorific value and may be able to withstand mechanical handling and be useful for household and cottage industries locally.

Effect on the fatty acid profiles of a microalgae strain (Dunaliella tertiolecta) using different lipid extraction techniques

Biodiesel is subject of research because it is less polluting when used in pure form or mixed with petroleum diesel. Microalgae are now a material new in research for mass production of biodiesel, so the techniques used for cell growth, biomass extraction and lipid extraction influence the profile of fatty acids susceptible to transesterification and consequently the quality of biofuel. This work shows the effect on the fatty acid profile of a Dunaliella tertiolecta strain using two lipid extraction techniques. For this, the culture was carried out in the medium F/2, the recovery of the biomass was carried out by sedimentation-flocculation with NaOH and once dry it was subjected to extraction with solvent by Soxhlet and by ultrasound to obtain lipids under the methodology by Bligh &amp; Dyer. The fatty acids were analyzed by gas chromatography and the profile is made up of saturated-monounsaturated-polyunsaturated fatty acids and shows differences regarding the presence-absence and dry weight content. This represents a contribution to analyze the effect on physicochemical parameters established in Mexican regulations regarding the quality of biodiesel and to determine the potential of the microalgae strain for such production.

Ecological аnd Economic Aspects оf Content Maintenance оf Functional аnd Technological Tools оf Housing аnd Communal Services Economy оf Ukraine

The systems of heat, gas and electricity supply in settlements of Ukraine today are an example of inefficient use of fuel and energy resources in the state. Substitution of the main fuel – natural gas – for the needs of heat sources, electricity by alternative provides an imaginary saving of local budgets in the conditions of decentralization of public administration (due to the difference between the prices of natural gas and other organic fuels). At the same time, these measures alone raise a number of other problems. Increasing environmental pollution is one of them. The legislative support, tariff policy, requirements of current regulations in the field of environmental safety, production and sale of heat and electricity to consumers are analysed. According to them, the replacement of natural gas with alternative fuels is considered. Estimated cost of energy received, emissions of pollutants and greenhouse gases into the atmosphere are calculated. Emission indices were obtained based on data on the physicochemical composition and consumption of each of the fuels, taking into account the characteristics of combustion processes and measures to reduce the emissions of a particular ingredient. A comparative analysis of the fuels has been performed in relation to the environmental impact of the combustion products and the cost of the fuels themselves. In rural areas, after converting agricultural waste and wood processing as secondary raw materials into quality biofuels, it is advisable to introduce the replacement of traditional natural gas with alternative fuels. In urban areas, due to the implementation of measures to improve the energy efficiency of existing buildings and structures, it is possible to reduce the consumption of traditional natural gas, and the savings can be directed to their thermal modernization. This will allow the most environmentally friendly natural gas to be left as the main organic fuel for district heating needs.

ALTERNATIVE FUELS FROM TECHNICAL OILS: INNOVATIVE METHODS AND TECHNOLOGIES OF OBTAINING AND USING

The chemical aspects of increasing the efficiency of processing rape or soy-gm oils (oils in general) into biofuel by two methods are considered. These methods involve: traditional alcoholysis by methanol or ethanol and a new method — esterolysis which is based on reesterification reaction of ester oils mollecules by indusrially produced non-oil esters. The comparison of chemical-technological foundations of oils processing by traditional etanolysis and esterolysis by ethyl-acetate revealed that both technologies demonstrate unsatisfactory indicators of their efficiency, in particular temperature regime, selectiveness in relation to biofuels, output, quality and others, despite certain advantages of esterolysis. It is determined that overcoming the major reasons and consequences of low efficiency of these two methods is possible with the help of the innovative two-stage approach to the realization of technologies of ethanolysis and esterolysis. The chemical-technological principles of each stage of the two-stage processes have been developed, and the conditions of their procedure have been optimized. At the first stage, the alcoholysis of oils by glycerine, the so-called glycerolysis-2, is carried out, with the aim of changing triacyl-glycerine oils molecules into monoacyl-glycerine molecules. The second stage includes ethanolysis or esterolysis of monoacyl-glycerine molecules. The comparative analysis of the given material balances of technologies for one-stage and two-stage types of ethanolysis and esterolysis demonstrated a considerable increase of efficiency, mainly selectiveness, output and quality of biofuel. A new technique of optimizing the temperature regime of technologies for processing oils into biofuels is suggested. It is shown that the biofuel obtained with the help of two-stage ethanolysis is of better quality. It is confirmed that the most rational direction of using biofuel is the formation of composite diesel fuel. Ref. 12, Tab. 4.

Application of ISO standards on sampling and effects on the quality assessment of solid biofuel employed in a real power plant

Bioenergy is one of the main contributors in the renewable energy markets but the quality of solid biomass is often a concern. This study provides an application of the ISO 18135 on biomass sampling, evaluating how sampling procedure affects the analytical results and suggesting possible solutions to reach an acceptable level of precision for quality assessment.A sampling plan compliant with the aforementioned standard was carried out in a 21 MW biomass power plant located in Northern Italy in August and February, collecting samples of different typology from heaps stored in the plant and from trucks coming from suppliers. Moisture content analysis was performed for all the samples, and for those from heaps ash and nitrogen contents were also investigated.Considering moisture content, to achieve a good precision, a significantly different number of increments are needed in August and February. Regarding ash content, it would be impossible to obtain the precision suggested by the standard, because it would lead to a number of increments not in line with practical operations. Nitrogen content is not a concern in this case, because of the measured low values. In general terms, precision values suggested by ISO 18135 require a high effort by operator and resulted unsuitable in terms of practical application for moisture and ash contents. This is probably due to the different solid biomass considered during the standard development.For this reason, it is important to assess the quality of the different solid biofuels in order to tune the sampling procedure accordingly.

Exploration of microalgal species for simultaneous wastewater treatment and biofuel production

Microalgal isolates obtained from stream water and wastewater treatment plant were examined to select a suitable microalgal species capable of simultaneously removing nutrient and producing biofuel. Ten isolates were identified using internal transcribed spacer (ITS) region sequencing analysis and were determined to be green microalgae, belonging to phylum Chlorophyta. The highest nutrient removal rates of 8.1 mg-T-N/L-d and 1.6 mg-T-P/L-d were achieved by Chlorella sorokiniana UTEX 1810 under photo-autotrophic cultivation conditions. Fatty acid methyl ester (FAME) composition analysis was conducted to estimate biofuel quality using gas chromatography with mass spectrometry on the basis of the lipid content extracted from microalgal cell. The composition of FAME is mainly composed of palmitic acid (C16:0), stearic acid (C18:0), linoleic acid (C18:2), and heneicosanoic acid (C21:0). These results suggest that C. sorokiniana UTEX 1810 is a promising candidate for simultaneous removal of nutrient and biofuel production from wastewater.

Energy metrics of fuel juxtaposed with mass yield metrics

Abstract Without oxygen, there would be no combustion. Yet the crucial role of oxygen in energy systems has been largely underrepresented. The oxygen-dependence of fuel caloricity is used to derive energy-based metrics that challenge the prime facie objective of maximising biofuel mass yields—an objective that currently dominates the biofuel industry. Application of two energy metrics, namely the change in energy quality ( Δ E Q ) and the energy yield ( Δ E η ), demonstrates that any improvement in energy quality of combustibles must accompany increases in combusted oxygen ( m O 2 ), as Δ E Q = m O 2 | product m O 2 | feed − 1 , and that Δ E η is a function mass yield, η , and m O 2 : Δ E η = η ( m O 2 | product m O 2 | feed ) . Literature data produced mostly positive Δ E Q values: biocrude achieved the highest ( 126.3 % ), followed by bioethanol ( 107.7 % ), and catalytic pyrolysis ( 78.3 % ). Most data produced similar changes in energy yield per mass yield, Δ E η / Δ m η ranging from 0.7 for biodiesel to 1.6 for bioethanol. Carbon yields and overall mass yields are demonstrated to be poor metrics for biofuel synthesis, and could undermine biofuel quality, hampering progress for conversion technologies aimed at producing biofuels. Biodiesel mass yields in particular were found to be inflated by as much as 73 % . As such, Δ E Q and Δ E η are useful for cross-field comparison of biofuels.

Facile Synthesis of Kilogram-Scale Co-Alloyed Pt Single-Atom Catalysts via Ball Milling for Hydrodeoxygenation of 5-Hydroxymethylfurfural

Catalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) into high quality biofuel 2,5-dimethylfuran (DMF) is significant for the utilization of biomass but remains a substantial chall...

Recycling of kebab restoration grease for bioenergy production through acoustic cavitation

The use of renewable energies to combat climate change is one of the greatest goals for humanity. To achieve this objective, one alternative is to valorize and recycle wastes, i.e. food waste, generated daily due to our way of life. Every day, human beings generate thousands of tons of this organic matter that can be recycled to produce bioenergy. Food waste is a source of carbon that must be included into the carbon dioxide cycle. In this manuscript, we propose to recycle the organic waste produced in a kebab local restaurant through biodiesel production, assisted by clean energy i.e. ultrasound. Biodiesel of both chicken grease and a mixture of beef-lamb were synthesized and optimized by response surface methodology and desirability function. Fatty acid methyl ester yields were higher (97.42% w/w for chicken grease and 96.98 for beef-lamb grease) than the minimum threshold established by European regulation EN 14214 (≥96.5% w/w). Although, cold-filter plugging point and oxidation stability resulted in values far from those established by the EN 14214 standard. To improve them while meeting standard threshold, both antifreeze and antioxidant were added following a design of experiments. The addition of antioxidant t-butyl-hydroxyquinone (TBHQ) at concentrations between 800 and 900 ppm and a commercial antifreeze at concentrations above 0.08% v/v, significantly improved biofuel quality in terms of storage and cold flow properties. We can conclude that animal fat residues from kebab restoration can provide suitable biodiesel if antioxidants and antifreezes are added.

Effective pyrolysis of waste cooking oils into hydrocarbon rich biofuel on novel mesoporous catalyst with acid and alkali coexisting

The high value usage of waste biomass-based resources is highly demanded. Here we synthesized an acid and base based on SBA-15 bifunctional catalyst, SBA-15@MgO@Zn, for the catalytic pyrolysis of waste cooking oils (WCO) into hydrocarbon rich biofuel with deoxygenation. First, CC bond broke at Lewis acid sites to form hydrocarbons and short-chain fatty acids, and then these short-chain fatty acids deoxidized at the basic sites to form hydrocarbon compounds. Therefore, the acid and base coexist bifunctional catalyst overcomes not only the shortcomings for the acidic catalysts that easily produce coke, but also for the basic catalysts that induces saponification during the catalytic pyrolysis of high acid value WCO. At the same time, this kind of high efficient catalyst makes deoxidation in the process of the pyrolysis, which not only improves the quality of biofuel, but also simplifies the production process.

Improved biofuel quality in catalytic cracking of triglyceride-rich biomass over nanocrystalline and hierarchical ZSM-5 catalysts

Improved biofuel quality in catalytic cracking of triglyceride-rich biomass over nanocrystalline and hierarchical ZSM-5 catalysts

A scheduling and planning algorithm for microalgal cultivation and harvesting for biofuel production

Microalgae is highlighted as the most feasible bioenergy feedstock because it can produce high amounts of lipids, carbohydrates, and hydrogen, which are necessary compounds for the production of various biofuels, while only requiring minimal water and land due to high photosynthetic efficiency. However, there are technical limitations that negatively influence the mass production of biofuel from algae, making it economically infeasible on a commercial scale. One of these bottlenecks exist in its cultivation. The cultivation method and system are critical in determining the amount and quality of biofuel that may be generated from the microalgae. Additionally, the peak biomass concentration, and productivities for the different compounds and nutrients within microalgae do not occur at the same time. Hence, this work proposes a planning tool for microalgae cultivation systems that incorporates species selection, and cultivation and harvesting approach selection and scheduling, while balancing the minimization of environmental impact and maximization of profit realized. The capabilities of the proposed decision support model is demonstrated through a hypothetical case study. Scenario analyses is likewise conducted to establish an understanding of system behavior and performance over time and under various conditions. The results of the computational experiments show the tools capabilities in simultaneously considering algae growth rates and compound productivities in decision making, for instance biomass species that is able to generate the most of a certain high value fuel is prioritized in cultivation and harvesting.

Assessment of different carbon and salinity level on growth kinetics, lipid, and starch composition of Chlorella vulgaris SAG 211-12

ABSTRACTThe quality of microalgal biofuel depends on the fatty acid (FA) distribution. A high ratio of saturated fatty acids (SFAs) favors better biofuel characteristics. Palmitic acid (C16:0) and stearic acid (C18:0) are essential FAs for required biodiesel quality. In this study, combined effects of growth medium concentrations of NaCl, glucose and glycerol on cell composition and FA profile of the Chlorella vulgaris SAG 211–12 were investigated. A central composite design (CCD) based design of experiments (DoE) was used for experimental setup. According to experimental results, the maximum mass fraction for palmitic acid (C16:0), 40.67% of total fatty acids, was obtained in the medium supplemented with 0.9% (w/v) NaCl, 0.3% (w/v) glucose, and 0.3% (w/v) glycerol, whereas stearic acid (C18:0) percentage reached the highest value of 22.16% of total fatty acids in the presence of 2.5% NaCl, 0.6% glucose, and 0.6% glycerol. According to the same set of designed experiments, best starch content was found as 22.08% of dry cell weight in a medium containing 2.0% NaCl, 0.3% glucose, and 0.3% glycerol. C16:0 mass fraction as a function of three medium ingredient concentrations was modeled using a Kriging model. Optimum concentrations of NaCl, glucose and glycerol to reach maximum C16:0 fraction were predicted as 0.5, 1, and 1%, respectively.

The effect of liming and nitrogen application on common osier and black poplar biomass productivity and determination of biofuel quality indicators

Experiments with two short rotation woody energy crops, common osier (Salix viminalis L.) and black poplar (Populus nigra L.) were carried out in Western Lithuania (55°43′ N, 21°27′ E) on a naturally acid moraine loamy Retisol. According to the results averaged over the two successive growing rotations (2008–2012 and 2013–2016), the dry matter (DM) yield of common osier amounted to 74.76 t ha−1 and 71.63 t ha−1, respectively and that of black poplar totalled 42.28 and 54.24 t ha−1. Nitrogen fertilization significantly increased the number of stems and DM yield for both crops, while stem height was increased only for osier. High-quality chaff of common osier and black poplar was produced using a screw chopper. Our study evidenced that common osier and black poplar biomass feedstock meets the requirements for high quality solid biofuel. When chopped by a screw chopper, wet chaff (40–55% moisture content) may be burned in high and medium power boilers equipped with combustion devices suitable for the incineration of wet chopped woody plants.

Methanation potential: Suitable catalyst and optimized process conditions for upgrading biogas to reach gas grid requirements

Increasing CO2 and greenhouse gas emissions are decreasing the living conditions all around the world and considerable damage is inflicted on our planet. Creating solutions for clean energy, air, water and food is becoming inevitable and urgent. This paper focuses on upgrading biogas to high quality biofuel to meet German gas grid requirements. The Sabatier process has proven that carbon dioxide present in biogas can be converted to methane (>96% -Vol) by adding hydrogen in a stoichiometric ratio. High quality methane yield 98.9%, with CO2 conversion 99.6% is achieved with a Nickel catalyst and with process conditions of temperature (473.15 K), pressure (1000 kpa), H2/CO2 ratio (6), CH4/CO2 ratio (1.52), a flow rate of 1.11 × 10−6 m3 s−1 for the reactor dimensions of a diameter of 0.1 m, a catalyst bed height of 0.14 m, a catalyst amount of 0.01 kg and a reactor volume of 1.099 × 10−3 m3. These experimental laboratory parameters are beneficial as a reference for upscaling Methanation reactors.

Comprehensively utilization of spent bleaching clay for producing high quality bio-fuel via fast pyrolysis process

High-quality bio-fuel (low oxygen content and acid value, high calorific value) was produced by catalytic pyrolysis of clay oil over calcined clay. Both feedstock (clay oil) and catalyst (calcined clay) were obtained from spent bleaching clay (SBC) deriving out of edible oil plants. The calcined clay was characterized with inductively coupled plasma-atomic emission spectrometry (ICP-AES), N2 adsorption/desorption analyses, X-Ray Diffraction (XRD), temperature programmed desorption of ammonia and carbon dioxide (NH3-TPD and CO2-TPD). Catalytic pyrolysis experiments were conducted to investigate the effects of several parameters on the product distribution, including pyrolysis temperature, weight hourly space velocity (WHSV) and residence time. The optimal conditions for produce high quality bio-fuel were 550 °C with WHSV of 2.5 h−1 and residence time of 1.65 s. The low heating value of bio-oil was increased by 13%–46.36 kJ/g, as long as the acid value was decreased by 97% to 1.16 mg/g KOH. The calcined clay catalyst showed slight deactivation after 4 cycles. Therefore, fast pyrolysis process is a rapid and efficient method of valorising spent bleaching clay from waste oils for high quality bio-fuel.