Tag Archives: biofuels

928-939 N. Sjulander, V. Rooni, L. Rocha-Meneses and T. Kikas
Comparison of different chemical-free pretreatment methods for the production of sugars, ethanol and methane from lignocellulosic biomass
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Comparison of different chemical-free pretreatment methods for the production of sugars, ethanol and methane from lignocellulosic biomass

N. Sjulander¹*, V. Rooni¹, L. Rocha-Meneses² and T. Kikas¹*

¹Estonian University of Life Sciences, Institute of Forestry and Engineering, Chair of Biosystems Engineering, EE51014 Tartu, Estonia
²Renewable and Sustainable Energy Research Center, Technology Innovation Institute, P.O.Box: 9639, Masdar City, Abu Dhabi, United Arab Emirates
*Correspondence: nikki.sjulander@emu.ee; timo.kikas@emu.ee

Abstract:

Most pretreatment methods for lignocellulosic biomass use strong chemicals, such as sulphuric acid and ammonia, to open up the cellular structure of plant biomass. However, those chemicals are not environmentally friendly and their use leads to safety risks. As a result, different chemical-free pretreatment methods have been developed, which focus on the usage of pressure, high or low temperatures and mild chemicals. Freezing pretreatment and explosive decompression pretreatments, using different operating gases, such as nitrogen and steam, are compared in the context of glucose, ethanol and methane yield in this review. For the methane production, the stillage from bioethanol production is used. The usage of this waste improves the overall valorisation of lignocellulosic biomass. The review also investigates, whether the nitrogen explosive decompression pretreatment is suitable for the treatment of softwoods, hardwoods and herbaceous materials. In the comparison of different chemical-free pretreatment methods, it is concluded that heat and water are the most influential parameters for opening up the lignocellulosic biomass structure. The operating gas and pressure in the pretreatment reactor are less relevant. Steam explosion, nitrogen explosive decompression pretreatment and autohydrolysis pretreatment are the most suitable chemical-free pretreatment methods for lignocellulosic biomass.

Key words:

anaerobic digestion, biofuels, fermentation, lignocellulosic inhibitors, steam explosion

687–697 K. Bumbiere, A. Gancone, J. Pubule and D. Blumberga
Carbon balance of biogas production from maize in Latvian conditions
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Carbon balance of biogas production from maize in Latvian conditions

K. Bumbiere, A. Gancone, J. Pubule* and D. Blumberga

Riga Technical University, Institute of Energy Systems and Environment, Faculty of Electrical and Environmental Engineering, Azenes 12-K1, LV-1048 Riga, Latvia
*Correspondence: jelena.pubule@rtu.lv

Abstract:

Production of biogas using bioresources of agricultural origin plays an important role in Europe’s energy transition to sustainability. However, many substrates have been denounced in the last years as a result of differences of opinion on its impact on the environment, while finding new resources for renewable energy is a global issue. The aim of the study is to use a carbon balance method to evaluate the real impact on the atmosphere by carrying out a carbon balance to objectively quantify naturally or anthropogenically added or removed carbon dioxide from the atmosphere. This study uses Latvian data to determine the environmental impact of biogas production depending on the choice of substrate, in this case from specially grown maize silage. GHG emissions from specially grown maize use and cultivation (including the use of diesel fuel, crop residue and nitrogen fertilizer incorporation, photosynthesis), biogas production leaks, as well as digestate emissions (including digestate emissions and also saved nitrogen emissions by the use of digestate) are taken into account when compiling the carbon balance of maize. The results showed that biogas production from specially grown maize can save 1.86 kgCO₂eq emissions per 1 m³ of produced biogas.

Key words:

agriculture., bioenergy, biofuels, multicriteria analysis, sustainability

1498–1515 L.A. Souza, F.C. Silva, A.C.L. Maria, A.L. Belem, D. Cecchin and M.M. Barros
Response surface for biodiesel production from soybean oil by ethylic route
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Response surface for biodiesel production from soybean oil by ethylic route

L.A. Souza¹, F.C. Silva¹*, A.C.L. Maria¹, A.L. Belem¹, D. Cecchin¹ and M.M. Barros²

¹Federal Fluminense University, Agricultural and Environmental Engineering Department, 156 Rua Passos da Pátria 156, bloco D, sala 235, 24210-240, Niterói, Brasil
²Federal Rural University of Rio de Janeiro, Engineering Department, Rodovia BR 465, Km 07, s/n Zona Rural, 23890-000, Seropédica, Brasil
*Correspondence: flaviocastro@id.uff.br

Abstract:

Petroleum has been the most consumed energy source in the world, but it tends to run out due its non-renewable character. Among biofuels, biodiesel has emerged as the main candidate to substitute petroleum diesel. The present study aimed to identify the maximum yield point of biodiesel production by generating a response surface using molar ratio, temperature and agitation time as independent variables, and yield as a dependent variable. From the response surface, it is observed that the increase in temperature and reaction time leads to reduced yield. The configuration that resulted in maximum yield of 93.30% was 12:1 molar ratio, 30 °C temperature and 30-minute reaction time. From the chromatographic analysis it was possible to identify five different fatty acids in the composition of the biodiesels. Total saturated fatty acids (palmitic and stearic acids) ranged from 41.53% to 42.09% and total unsaturated fatty acids including monounsaturated and polyunsaturated fatty acids (oleic, linoleic and linolenic acids) ranged from 57.92% to 58.48%. According to the results of the physicochemical analyses, the specific mass at 68 °F is in agreement with Brazilian, American and European specifications, ranging from 877.46 kg m^-3 to 879.64 kg m^-3. The kinematic viscosity at 104 °F ranged from 4.49 mm² s^-1 to 4.82 mm² s^-1. The acid value obtained did not vary within the limits established by the norms, and values between 0.54 and 2.74 mg KOH g^-1 were observed.

Key words:

biofuels, ethanol, optimization, transesterification

957–973 J. Čedík, M. Pexa, D. Mader and R. Pražan
Combustion characteristics of compression ignition engine operating on rapeseed oil-diesel fuel blends
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Combustion characteristics of compression ignition engine operating on rapeseed oil-diesel fuel blends

J. Čedík¹*, M. Pexa¹, D. Mader¹ and R. Pražan²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ165 21 Prague 6, Czech Republic
²Research Institute of Agriculture Engineering, Drnovská 507, CZ161 01 Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

The effect of biofuels on the operational parameters of the combustion engines, such as performance parameters or emission production, are monitored often. These changes are, however, based on the effect of biofuels on the course of combustion pressure inside the combustion chamber. The contribution deals with the effect of rapeseed oil-diesel fuel blends on the combustion characteristics of turbocharged compression ignition engine. The course of cylinder pressure was monitored and analysed and heat release rate was calculated. The brake specific fuel consumption, indicated and brake thermal efficiency were calculated and evaluated, in-cylinder temperature and ignition delay were also evaluated. As a test fuels a 5% and 20% concentrations of rapeseed oil in diesel fuel were selected while 100% diesel fuel was used as a reference. Turbocharged CI engine Zetor 1204 located in the tractor Zetor Forterra 8642 was used for measurement. During measurement the rotation speed of the engine was kept constant at approx. 1,950 min^-1 and the load of the engine was selected at approx. 20, 60, 80 and 100%. The results showed decreased cylinder peak pressure, decreased intensity of heat release rate and earlier end of combustion in all tested loads for both tested fuel blends in comparison with diesel fuel, while the lowest peak cylinder pressure was reached using fuel with 5% rapeseed oil. Fuel with 5% rapeseed oil also showed highest indicated efficiency. Ignition delay was found shorter with both of the blended fuels in comparison with diesel fuel.

Key words:

biofuels, cylinder pressure, engine efficiency, heat release rate

1001–1012 M. Holúbek, M. Pexa, J. Čedík and D. Mader
Effect of long-term operation of combustion engine running on n-butanol – rapeseed oil – diesel fuel blend
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Effect of long-term operation of combustion engine running on n-butanol – rapeseed oil – diesel fuel blend

M. Holúbek*, M. Pexa, J. Čedík and D. Mader

Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ165 21, Prague 6, Czech Republic
*Correspondence: holubekm@tf.czu.cz

Abstract:

The short time use of biofuels in compression ignition engines is being studied by many authors. However, in many cases the real long–term operation of the engine on biofuels may cause problems. The article deals with the operation parameters of the combustion engine, fuelled by n-butanol – rapeseed oil – diesel fuel blend, during 70 hours operation in total. Two brand new diesel power generators Kipor KDE 6500 with output power of 4.6 kW were used for certain testing. The first generator was operated on 100% diesel fuel and it was used as a reference and the second generator was operated on experimental fuel containing 10% n-butanol – 20% rapeseed oil – 70% diesel fuel blend. The generators were equipped with single cylinder compression ignition engine Kipor KM 186 with the rated power of 5.7 kW. For the first 10 operating hours approx. 40% load was applied. Then, the generators worked for another 60 operating hours with approx. 70% load. The harmful emissions, smoke, fuel consumption and the amount of produced particles were also measured after 10 hours run-in period and then after another 60 hours of operation. Consequently, the results were compared. Measurements were carried out at gradually increasing electric power output, approx. 14%, 28%, 42%, 56%, 68%, 82% and 95% (in results can be found in Watts). Emission analyser and opacimeter BrainBee and Engine Exhaust Particle Sizer TSI were used for the measurements. The results showed increased production of emission of the engine running on fuel blend after 70 hours of operation. On the other hand, engine which operated on standard diesel reached lower fuel consumption. After 70 hours the blended fuel tended to produce more particles in comparison with diesel fuel.

Key words:

biofuels, emissions., fuel consumption, opacimeter, particles, power generator

985-996 J. Čedík, M. Pexa, M. Holůbek, D. Mader and R. Pražan
Effect of sunflower and rapeseed oil on production of solid particles and performance of diesel engine
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Effect of sunflower and rapeseed oil on production of solid particles and performance of diesel engine

J. Čedík¹*, M. Pexa¹, M. Holůbek¹, D. Mader¹ and R. Pražan²

Abstract:

The development of biofuels for compression ignition engines is heading primarily to utilization of vegetable oils. Combusting of 100% vegetable oil in unmodified CI engine is usually not possible due to higher viscosity of the vegetable oil. In order to use 100% vegetable oil in CI engine the oil needs to be preheated, esterified or hydrotreated. Alternatively, in order to use raw vegetable oil in CI engine without preheating it is possible to use vegetable oil – diesel fuel blends or vegetable oil – butanol – diesel fuel blends in order to lower the viscosity of the fuel. The contribution focuses on comparison of the effect of sunflower and rapeseed vegetable oils on operational parameters of the turbocharged compression ignition engine, especially on production of solid particles. The measurement was carried out according to standardized NRSC test cycle. 5% and 20% concentration of vegetable oils in diesel fuel were used as a test fuels for the measurement while the diesel fuel was used as a reference. The count and size of solid particles were measured by means of EEPS particle analyser. Based on the measured values it can be stated that the slight increase of performance parameters occurred with strong effect on emissions production, especially on production of solid particles.

Key words:

biofuels, combustion engine, diesel fuel, fuel blend, particulate matter, vegetable oil

547-555 M. Pexa, J. Čedík and R. Pražan
Smoke and NOX emissions of combustion engine using biofuels
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Smoke and NOX emissions of combustion engine using biofuels

M. Pexa¹*, J. Čedík¹ and R. Pražan²

¹Czech University of Life Sciences, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamycka 129, CZ 16521 Prague 6, Czech Republic
²Research Institute of Agricultural Engineering, p.r.i., Drnovská 507, CZ 16101 Prague 6, Czech Republic
*Correspondence: pexa@tf.czu.cz

Abstract:

Production of solid particles significantly increases the dangerousness of combustion engines. The excellent sorbtion characteristics of the solid particles increases their harmful effects and makes them very dangerous component of emissions which causes health problems. Currently there are many design solutions which aim to reduce smoke of combustion engines. One of the most significant solutions suggests increasing the injection pressures up to the limit of 250 MPa and filtering the exhaust gases. The paper compares different fuels and biofuels, whether used alone or in mixtures, and their effect on smoke of supercharged CI engine. The comparison uses the 8-point NRSC (Non-Road Steady Cycle) test during which the following fuels were used: diesel, rapeseed methyl ester, rapeseed oil, Jatropha curcas oil, biobutanol, hydrotreated oil and other blended fuels. The measurement and comparison results show that using biofuels can significantly reduce smoke of combustion engine by up to tens of percent in comparison to diesel.

Key words:

biofuels, combustion engine, harmful emissions, performance

783–789 P. Jindra, M. Kotek, J. Mařík and M. Vojtíšek
Effect of different biofuels to particulate matters production
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Effect of different biofuels to particulate matters production

P. Jindra¹*, M. Kotek¹, J. Mařík¹ and M. Vojtíšek²

¹Czech University of Life Science Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ 16521 Prague, Czech republic
²Czech Technical University in Prague, Faculty of Mechanical Engineering, Center of Vehicles for Sustainable Mobility, Technická 4, CZ 16607 Prague, Czech Republic
*Correspondence: jindrap@tf.czu.cz

Abstract:

In recent years the European Union has exhibited a significant interest in the reduction of crude oil usage. Biofuels can be used in conventional engines but the biofuels should reduce the emissions produced by internal combustion engines. This article deals with analysis of particulate matters (PM) production in chosen biofuels burned in internal combustion engine Zetor 1505. The conventional emission analysers are capable to detect gaseous emission components but they are not able to classify PM. Analysis of PM was performed with a TSI Engine Exhaust Particle Sizer 3090 which is able to classify particles from 5.6 nm to 560 nm. The device analysed different blends of alcohol–based biofuels tested under NRSC cycle conditions. The given size of PM can be taken as an impact on human organism’s cells consequently human health. PM create an ideal medium for polyaromatic hydrocarbons (PAH), their composition and structure. Analysis of PM should become a standard component of every emission parameter assessment.

Key words:

biofuels, emissions., particulate matters

613-620 M. Pexa, J. Čedík,, J. Mařík, V. Hönig, Š. Horníčková and K. Kubín
Comparison of the operating characteristics of the internal combustion engine using rapeseed oil methyl ester and hydrogenated oil
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Comparison of the operating characteristics of the internal combustion engine using rapeseed oil methyl ester and hydrogenated oil

M. Pexa¹, J. Čedík¹,*, J. Mařík¹, V. Hönig², Š. Horníčková² and K. Kubín³

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521 Prague 6, Czech Republic; *Correspondence: cedikj@tf.czu.cz
²Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ16521 Prague 6, Czech Republic
³Research Institute of Agricultural Engineering, p.r.i., Drnovská 507, CZ16101 Prague 6, Czech Republic

Abstract:

The issue of the use of alternative fuels in diesel engines is discussed in this paper. The purpose is to reduce the dependence of EU Member States on fuels of petroleum origin. One of the possibilities is the use of oils from biological materials. The use of the oil in standard engines is not usually possible. The engine modification or the fuel modification is necessary. Esterification or hydrogenation of oils can be used as the fuel modification. Impact of these changes on the operational characteristics of a turbocharged internal combustion engine is observed in the paper. The internal combustion engine of the tractor Zetor Foretrra 8641 was used for testing. This engine was burdened using a dynamometer to the PTO. Performance and fuel consumption of the engine were monitored during measurement. As fuels the 100% rapeseed methyl ester and 100% hydrogenated oil was elected. Based on the results we can say that the operating parameters of the internal combustion engine does not change significantly when using these fuels.

Key words:

biofuels, combustion engine, fuel consumption, HVO., power, RME, vegetable oil

541-549 J. Čedík,, M. Pexa, J. Mařík, V. Hönig, Š. Horníčková and K. Kubín
Influence of butanol and FAME blends on operational characteristics of compression ignition engine
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Influence of butanol and FAME blends on operational characteristics of compression ignition engine

J. Čedík¹,*, M. Pexa¹, J. Mařík¹, V. Hönig², Š. Horníčková² and K. Kubín³

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521 Prague 6, Czech Republic; *Correspondence cedikj@tf.czu.cz
²Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ16521 Prague 6, Czech Republic
³Research Institute of Agricultural Engineering, p.r.i., Drnovská 507, CZ16101 Prague 6, Czech Republic

Abstract:

The issue of the use of alternative fuels in diesel engines is discussed in this paper. The purpose is to reduce the dependence of EU Member States on fuels of petroleum origin. One of the possibilities is the use of butanol produced from organic products. The use of pure butanol in diesel engines is not possible. However, it may be used as an additive for fuels of petroleum origin or adding to oil for improving the operating conditions of the engine. Successively 10, 30 and 50% n-butanol was used as an additive. Turbocharged combustion engine of the tractor Zetor 8641 Foretrra was used to the test. This engine was burdened using a dynamometer to the PTO. Performance parameters and fuel consumption of the engine were monitored during measurements. Performance parameters of the engine decreases and fuel consumption increases due to the properties of butanol. Cleansing properties of butanol which restrict carbonization on functional surfaces of the engine seems advantageous.

Key words:

biofuels, butanol, combustion engine, FAME., fuel consumption, power