- Email: [email protected]
Development of rape seed oil burners for drying and heating
Industrial Crops and Products 7 (1998) 273 – 279
Development of rape seed oil burners for drying and heating Gilles Vaitilingom a,*, Christelle Perilhon b, Alain Liennard a, Michel Gandon b a
CIRAD-SAR, BP 5035, rue J.F. Breton, 34032 Montpellier Cedex 1, France b IRIBIOM, rue Le´onard de Vinci, 45072 Orle´ans Cedex 2, France Received 6 August 1996; accepted 28 February 1997
Abstract IRIBIOM and CIRAD carried out important experiments on the use of rape seed oil as a substitution for domestic fuel in burners. The first objective was to check the ability of rape seed oil as a biofuel in standard commercial burners. The second objective was to define the modifications to apply to standard burners for an efficient combustion with rape seed oil as well as with domestic fuel. Tests were conducted on a fully-monitored 260 kW boiler test-bench. Performance data, temperatures and pressures of the fuels, as well as gaseous emissions (CO, CO2, O2, NOx, SO2, PAH, cetons and aldehydes) were measured for rape seed oils and domestic fuel. Crude, degummed and refined rape seed oils were tested. The optimisation of the combustion was investigated for different spray nozzles by adjusting: (i) the position of the flame stabilizer; (ii) the opening of the air valve; (iii) the temperature at the tip of the spray nozzle (from 80°C to 150°C); and (iv) the rape seed oil injection pressure. Crude industrial rape seed oils led to filter clogging in few minutes. With degummed and refined rape seed oil a new spray nozzle was determined to avoid fouling and coking problems. Performance data and combustion efficiency was equal to that of domestic fuel. The emission values obtained with the optimal adjustments are far below the limits defined by the European norm in force. The high viscosity of rape seed oil causes poor fuel atomization and difficulty for its ignition, additionally the physical and chemical characteristics of vegetable oils lead to imperfect evaporation of droplets that can cause severe deposits in the combustion chamber of the boiler. Therefore it was necessary to heat the oil and raise the injection pressure in the nozzle. The ability of rape seed oil as a biofuel in burners was proved and confirmed by on site durability tests for grain drying and urban heating. © 1998 Elsevier Science B.V. Keywords: Vegetable oil; Rape seed oil; Biofuel; Burner; Heating; Drying
1. Introduction
* Corresponding author. Fax: +33 467611223.
In Europe vegetable oils used as biofuels offer new agricultural opportunities and allow a reduction of the set aside lands enforced by the regula-
0926-6690/98/$19.00 © 1998 Elsevier Science B.V. All rights reserved. PII S 0 9 2 6 - 6 6 9 0 ( 9 7 ) 0 0 0 5 8 - 7
274
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
Table 1 Characteristics of rape seed oil and fuel oil
Viscosity at 20°C (mm2/s) Lower calorific value (kJ/kg) Density (kg/m3) Sulphur content
Rape seed oil
Domestic fuel oil FOD
Heavy fuel oil FOD no.2
77 37 440 920 0
59.5 42 960 5880 50.3% mass
110 – 380 at 50°C 40 510
tion. In developing countries biofuels can be used in substitution to petroleum fuels reducing dependencies, saving foreign currencies and opening new access to energy in remote areas. Additionally, beside the economic and technical divergences, all the recent international conferences on biofuels concluded that research and experiments must be supported to prepare the future in energy. One of the most important experiments was managed by a technical centre (IRIBIOM), working in collaboration with a public research centre: CIRAD (Centre de coope´ration Internationale en Recherche Agronomique pour le De´veloppement) and the University of Orle´ans: ESEM (Ecole Supe´rieure de l’Energie et des Mate´riaux). With the support of ADEME (Agence De l’Environnement et de la Maıˆtrise de l’Energie), CUENOD (burners manufacturer), Conseil Ge´ne´ral du Loiret (County Council of Loiret) and Conseil Re´gional
54% mass
de la Re´gion Centre (Regional Council of Centre). The aim of this study was to define the settings of standard burners for the use of pure rape seed oil as fuel with the possibility of reversibility rape/domestic fuel. The first objective was to check the ability of rape seed oil as a biofuel in standard commercial burners. The second objective was to define the modifications to apply to standard burners for an efficient combustion with rape seed oil as well as with domestic fuel. Therefore the parameters of efficiency and smoke quality were studied in relation with air and fuel flows, pressures and temperatures. The characteristics of rape seed oil are close to those of domestic fuel oil as shown in Table 1. A large number of experiments have been initiated since 1980 on rape seed oil as fuel in diesel engines. But very few studies were published or mentioned in literature on its use as fuel for burners.
Fig. 1. The laboratory test bench.
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
275
Fig. 2. CO rate variations.
In diesel engines the major problem is the formation of severe deposits in the combustion chamber and coking of the injectors while using vegetable oils. This problem is believed to be related to the high viscosity of the vegetable oils. This physical difference with diesel fuel affects the injection and the spray characteristics and could
decrease the performance of vegetable oils. But similar observations can be made in heavy fuel engines using vegetable oils although they are adapted to higher viscosity fuels. This can lead to the conclusion that chemicals characteristics are much more dominant. The durability problems encountered with the use of vegetable oils appear
Fig. 3. NOx rate variations.
276
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
Table 2 Emissions values with rape seed oil for the optimal adjustment compared to European norm Burner C22.2
CO (ppm)
NOx (ppm)
CO2 (%)
Air excess (%)
Partial load Full load EN 267 norm
47 51 100
62 67 150
13.6 11.4
17 39
to be very strong functions of engine types, with direct injection engines being more susceptible than indirect injection engines (Ryan et al., 1982), where thermal conditions are different between the two types of engine. Therefore it was decided not to work with sophisticated heavy fuel burners that could improve fuel atomization but risk to do not solve the problem of combustion and fouling of the boiler walls. It was decided to work with standard burners, cheaper than heavy fuel ones, able to be adjusted in pressure, temperature and air flow rate as required for this study.
2. Materials and methods A C22.2 CUENOD burner fixed on a 260 kW GUILLOT boiler was chosen for the tests with
Table 3 Results of domestic fuel in the standard commercial burner C22.0 compared with rape seed oil in the modified and optimized burner C22.2 Conditions
Domestic fuel C22.0
Rape seed C22.2
Flowrate (kg/h) Fuel temperature (°C) O2 (%) CO2 (%) CO (mg/Nm3) NO (mg/Nm3) NOx (mg/Nm3) SO2 (mg/Nm3) Exhaust temperature (°C) Ambiant temperature (°C) Efficiency (%) Air excess (%)
14.9 23 5.8 11.2 43 87 94 186 161 24.8 93.8 38
15.1 28 6 11.3 65 79 84 0 167 23.3 93.1 40
rape seed oils. This burner is adjusted to use ‘Austrian class 2’ light fuel that includes 30% of kerosene in domestic fuel, this mixture has a viscosity close to rape seed oil one. This burner is fitted with a fuel preheater system, its maximum flow rate is 22 kg/h of fuel. The standard commercial domestic fuel C22.0 CUENOD burner was used as reference for all the combustion and emissions comparisons. Tests were conducted on this fully-monitored boiler test-bench. Combustion efficiency, global efficiency of the boiler, fouling of the walls, fuel flow rates, spray pattern, global air flow, primary and secondary air flows, temperatures and pressures of the fuels, as well as gaseous emissions (CO, CO2, O2, NOx, PAH, cetons and aldehydes) were measured for rape seed oils and domestic fuel. Crude, degummed and refined rape seed oils were tested in the C22.2 burner This laboratory test bench is shown on Fig. 1. Temperatures are measured at different points of the installation. Fuel consumption is obtained by difference between inlet and outlet flow. The combustible pressure in the burner nozzle is measured. The combustion quality is analysed by the mean of classical measures such as: CO, CO2, O2, NOx, SO2 and by a qualitative observation of the cleanliness of the nozzle tip and of the boiler walls. A specific method (sampling and analyse by gaseous phase chromatography and spectrometry) allows the knowledge of non conventional pollutants (aldehydes, cetons, polycyclic aromatic hydrocarbons). After the preliminary tests the optimisation of the combustion was investigated for different spray nozzles by adjusting:
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
277
Fig. 4. The grain drying durability test.
The position of the flame stabilizer, the opening of the air valve, the temperature at the tip of the spray nozzle (from 80°C to 150°C) and the rape seed oil injection pressure.
3. Results
3.1. Start up and ignition of the rape seed spray The preliminary tests pointed out the great
Fig. 5. The heating durability test.
278
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
tendencies related to the use of rape seed oil in burners (Liennard and Gandon, 1995a,b). Necessity of a rape seed oil preheater system for the start up: no possible ignition under 80°C at 2 MPa, setting of the injection pressure to a higher level: from 1.3 to 3.5 MPa in the case of the C22.2.
3.2. Efficiency and optimisation of the combustion With crude industrial hot expressed rape seed oil, containing 180 ppm of phospholipids, the inlet filter of the burner pump was invariably clogged after 30 min even with an in line 30 mm prefiltration. It was decided to go on the study with degummed and refined rape seed oil. No significant differences between these two oils were recorded during all the tests. Once the oil preheated and the increase of the injection pressure adjusted the first tests showed: Reliable starting, performance and efficiency equal between rape seed oil in the C22.2 and domestic fuel in the C22.0, at same injected energy contents, rate of pollutants lower than the limits of the European directives in force, unburnt oil leaking and polymerising at the nozzle tip of the burner, quick fouling of the walls of the boiler where unburnt droplets of oil condensed and slowly pyrolysed. A new spray nozzle was chosen to avoid these fouling and coking problems. A central concentrated spray nozzle (type: 2 US Gal 80 R) provided the best results and was selected for the optimisation study and the durability tests. With these different adjustments of the burner the combustion was optimised according to exhaust gas emissions (Liennard and Gandon, 1995a,b). Concerning atomizing oil burners (which flowrate is lower than 100 kg/h), the EN 267 European norm specifies bonds not to be overstepped. The burner must be optimised in respect with these values. Fig. 2 and Fig. 3 show the variations of CO and NOx in relation with the adjustment of: The position of the flame stabilizer,
the opening of the air valve, the temperature at the tip of the spray nozzle (from 80°C to 150°C) and the rape seed oil injection pressure. The optimal adjustment is obtained such as the CO rate is minimum when CO2 rate is maximum (we look for a complete combustion with minimum air excess to keep good efficiency). The values obtained in this case for the rape seed oil fuel are shown in Table 2. Table 3 shows the comparison between domestic fuel in the C22.0 as reference and results for rape seed oil in the modified C22.2.
3.3. Durability tests Grain drying: The C22.2 modified burner was used during 200 h at 260 kW for maize drying near the city of Bourges (Centre Region). Refined rape seed oil was used and a data logger was installed to monitor this test (Fig. 4). The quality of the grain was analysed by the laboratory of AGPM (Association Ge´ne´rale des Producteurs de Mais—Maize growers association). The results are very good in term of efficiency and cleanliness of the grain (Liennard and Gandon, 1996a,b). Central heating: The aim was to check the ability of the modified burner in heating application where numerous starting are occurring at various moment depending only on the weather and the behaviour of the users (see Fig. 5). Degummed rape seed oil was used during 2 months in the 175 kW boiler of one wing of the Town-hall of the city of Orle´ans (Liennard and Gandon, 1996a,b). Despite hundreds of startings the boiler walls remained clean and the nozzle tip was not coked up.
4. Conclusion This study has proved that degummed or refined rape seed oil can be used in adapted commercial burners with very good results in term of efficiency, gas emissions level and durability. The behaviour of rape seed oil is similar in burners and in diesel engines. Despite its high viscosity and its physical and chemical character-
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
istics it is possible to modify and develop small to big size burners in respect with the interest of the users and the air quality regulation in force. This study has highlighted a new opening for rape seed oil and other vegetable oils, the use as biofuel in burners is far easier than in diesel powered vehicles in terms of technical or legislative constraint.
References Ryan, T.W., Callahan, T.J., Dodge, L.G., 1982. Characterization of vegetable oils for use as fuels in diesel engines. In: American Society of Agricultural Engineers (Ed.), Proceed-
.
279
ings of the International Conference on Plant and Vegetable Oils as Fuels, 2 – 4 August 1982, Fargo, ND, American Society of Agricultural Engineers, St. Joseph, MI, 70 – 81. Liennard, A., Gandon, M., 1995. Expe´rimentation de bruˆleurs a` huile de colza. Mesures et determination des caracteristiques necessaires au fonctionnement. CIRAD-SAR, report no. 1.95 (unpublished report), 102 pp. Liennard, A., Gandon, M., 1995. Expe´rimentation de bruˆleurs a` huile de colza. Objectifs: sechage et chauffage. CIRADSAR, report no. 83.95 (unpublished report), 68 pp. Liennard, A., Gandon, M., 1996. Expe´rimentation de bruˆleurs a` huile de colza. Fonctionnement d’un bruˆleur pour le sechage des graines. CIRAD-SAR, report no. 40.96 (unpublished report), 36 pp. Liennard, A., Gandon, M., 1996. Expe´rimentation de bruˆleurs a` huile de colza. Conclusions et perpectives. CIRAD-SAR, report no. 86.96 (unpublished report), 40 pp.
Development of rape seed oil burners for drying and heating Gilles Vaitilingom a,*, Christelle Perilhon b, Alain Liennard a, Michel Gandon b a
CIRAD-SAR, BP 5035, rue J.F. Breton, 34032 Montpellier Cedex 1, France b IRIBIOM, rue Le´onard de Vinci, 45072 Orle´ans Cedex 2, France Received 6 August 1996; accepted 28 February 1997
Abstract IRIBIOM and CIRAD carried out important experiments on the use of rape seed oil as a substitution for domestic fuel in burners. The first objective was to check the ability of rape seed oil as a biofuel in standard commercial burners. The second objective was to define the modifications to apply to standard burners for an efficient combustion with rape seed oil as well as with domestic fuel. Tests were conducted on a fully-monitored 260 kW boiler test-bench. Performance data, temperatures and pressures of the fuels, as well as gaseous emissions (CO, CO2, O2, NOx, SO2, PAH, cetons and aldehydes) were measured for rape seed oils and domestic fuel. Crude, degummed and refined rape seed oils were tested. The optimisation of the combustion was investigated for different spray nozzles by adjusting: (i) the position of the flame stabilizer; (ii) the opening of the air valve; (iii) the temperature at the tip of the spray nozzle (from 80°C to 150°C); and (iv) the rape seed oil injection pressure. Crude industrial rape seed oils led to filter clogging in few minutes. With degummed and refined rape seed oil a new spray nozzle was determined to avoid fouling and coking problems. Performance data and combustion efficiency was equal to that of domestic fuel. The emission values obtained with the optimal adjustments are far below the limits defined by the European norm in force. The high viscosity of rape seed oil causes poor fuel atomization and difficulty for its ignition, additionally the physical and chemical characteristics of vegetable oils lead to imperfect evaporation of droplets that can cause severe deposits in the combustion chamber of the boiler. Therefore it was necessary to heat the oil and raise the injection pressure in the nozzle. The ability of rape seed oil as a biofuel in burners was proved and confirmed by on site durability tests for grain drying and urban heating. © 1998 Elsevier Science B.V. Keywords: Vegetable oil; Rape seed oil; Biofuel; Burner; Heating; Drying
1. Introduction
* Corresponding author. Fax: +33 467611223.
In Europe vegetable oils used as biofuels offer new agricultural opportunities and allow a reduction of the set aside lands enforced by the regula-
0926-6690/98/$19.00 © 1998 Elsevier Science B.V. All rights reserved. PII S 0 9 2 6 - 6 6 9 0 ( 9 7 ) 0 0 0 5 8 - 7
274
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
Table 1 Characteristics of rape seed oil and fuel oil
Viscosity at 20°C (mm2/s) Lower calorific value (kJ/kg) Density (kg/m3) Sulphur content
Rape seed oil
Domestic fuel oil FOD
Heavy fuel oil FOD no.2
77 37 440 920 0
59.5 42 960 5880 50.3% mass
110 – 380 at 50°C 40 510
tion. In developing countries biofuels can be used in substitution to petroleum fuels reducing dependencies, saving foreign currencies and opening new access to energy in remote areas. Additionally, beside the economic and technical divergences, all the recent international conferences on biofuels concluded that research and experiments must be supported to prepare the future in energy. One of the most important experiments was managed by a technical centre (IRIBIOM), working in collaboration with a public research centre: CIRAD (Centre de coope´ration Internationale en Recherche Agronomique pour le De´veloppement) and the University of Orle´ans: ESEM (Ecole Supe´rieure de l’Energie et des Mate´riaux). With the support of ADEME (Agence De l’Environnement et de la Maıˆtrise de l’Energie), CUENOD (burners manufacturer), Conseil Ge´ne´ral du Loiret (County Council of Loiret) and Conseil Re´gional
54% mass
de la Re´gion Centre (Regional Council of Centre). The aim of this study was to define the settings of standard burners for the use of pure rape seed oil as fuel with the possibility of reversibility rape/domestic fuel. The first objective was to check the ability of rape seed oil as a biofuel in standard commercial burners. The second objective was to define the modifications to apply to standard burners for an efficient combustion with rape seed oil as well as with domestic fuel. Therefore the parameters of efficiency and smoke quality were studied in relation with air and fuel flows, pressures and temperatures. The characteristics of rape seed oil are close to those of domestic fuel oil as shown in Table 1. A large number of experiments have been initiated since 1980 on rape seed oil as fuel in diesel engines. But very few studies were published or mentioned in literature on its use as fuel for burners.
Fig. 1. The laboratory test bench.
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
275
Fig. 2. CO rate variations.
In diesel engines the major problem is the formation of severe deposits in the combustion chamber and coking of the injectors while using vegetable oils. This problem is believed to be related to the high viscosity of the vegetable oils. This physical difference with diesel fuel affects the injection and the spray characteristics and could
decrease the performance of vegetable oils. But similar observations can be made in heavy fuel engines using vegetable oils although they are adapted to higher viscosity fuels. This can lead to the conclusion that chemicals characteristics are much more dominant. The durability problems encountered with the use of vegetable oils appear
Fig. 3. NOx rate variations.
276
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
Table 2 Emissions values with rape seed oil for the optimal adjustment compared to European norm Burner C22.2
CO (ppm)
NOx (ppm)
CO2 (%)
Air excess (%)
Partial load Full load EN 267 norm
47 51 100
62 67 150
13.6 11.4
17 39
to be very strong functions of engine types, with direct injection engines being more susceptible than indirect injection engines (Ryan et al., 1982), where thermal conditions are different between the two types of engine. Therefore it was decided not to work with sophisticated heavy fuel burners that could improve fuel atomization but risk to do not solve the problem of combustion and fouling of the boiler walls. It was decided to work with standard burners, cheaper than heavy fuel ones, able to be adjusted in pressure, temperature and air flow rate as required for this study.
2. Materials and methods A C22.2 CUENOD burner fixed on a 260 kW GUILLOT boiler was chosen for the tests with
Table 3 Results of domestic fuel in the standard commercial burner C22.0 compared with rape seed oil in the modified and optimized burner C22.2 Conditions
Domestic fuel C22.0
Rape seed C22.2
Flowrate (kg/h) Fuel temperature (°C) O2 (%) CO2 (%) CO (mg/Nm3) NO (mg/Nm3) NOx (mg/Nm3) SO2 (mg/Nm3) Exhaust temperature (°C) Ambiant temperature (°C) Efficiency (%) Air excess (%)
14.9 23 5.8 11.2 43 87 94 186 161 24.8 93.8 38
15.1 28 6 11.3 65 79 84 0 167 23.3 93.1 40
rape seed oils. This burner is adjusted to use ‘Austrian class 2’ light fuel that includes 30% of kerosene in domestic fuel, this mixture has a viscosity close to rape seed oil one. This burner is fitted with a fuel preheater system, its maximum flow rate is 22 kg/h of fuel. The standard commercial domestic fuel C22.0 CUENOD burner was used as reference for all the combustion and emissions comparisons. Tests were conducted on this fully-monitored boiler test-bench. Combustion efficiency, global efficiency of the boiler, fouling of the walls, fuel flow rates, spray pattern, global air flow, primary and secondary air flows, temperatures and pressures of the fuels, as well as gaseous emissions (CO, CO2, O2, NOx, PAH, cetons and aldehydes) were measured for rape seed oils and domestic fuel. Crude, degummed and refined rape seed oils were tested in the C22.2 burner This laboratory test bench is shown on Fig. 1. Temperatures are measured at different points of the installation. Fuel consumption is obtained by difference between inlet and outlet flow. The combustible pressure in the burner nozzle is measured. The combustion quality is analysed by the mean of classical measures such as: CO, CO2, O2, NOx, SO2 and by a qualitative observation of the cleanliness of the nozzle tip and of the boiler walls. A specific method (sampling and analyse by gaseous phase chromatography and spectrometry) allows the knowledge of non conventional pollutants (aldehydes, cetons, polycyclic aromatic hydrocarbons). After the preliminary tests the optimisation of the combustion was investigated for different spray nozzles by adjusting:
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
277
Fig. 4. The grain drying durability test.
The position of the flame stabilizer, the opening of the air valve, the temperature at the tip of the spray nozzle (from 80°C to 150°C) and the rape seed oil injection pressure.
3. Results
3.1. Start up and ignition of the rape seed spray The preliminary tests pointed out the great
Fig. 5. The heating durability test.
278
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
tendencies related to the use of rape seed oil in burners (Liennard and Gandon, 1995a,b). Necessity of a rape seed oil preheater system for the start up: no possible ignition under 80°C at 2 MPa, setting of the injection pressure to a higher level: from 1.3 to 3.5 MPa in the case of the C22.2.
3.2. Efficiency and optimisation of the combustion With crude industrial hot expressed rape seed oil, containing 180 ppm of phospholipids, the inlet filter of the burner pump was invariably clogged after 30 min even with an in line 30 mm prefiltration. It was decided to go on the study with degummed and refined rape seed oil. No significant differences between these two oils were recorded during all the tests. Once the oil preheated and the increase of the injection pressure adjusted the first tests showed: Reliable starting, performance and efficiency equal between rape seed oil in the C22.2 and domestic fuel in the C22.0, at same injected energy contents, rate of pollutants lower than the limits of the European directives in force, unburnt oil leaking and polymerising at the nozzle tip of the burner, quick fouling of the walls of the boiler where unburnt droplets of oil condensed and slowly pyrolysed. A new spray nozzle was chosen to avoid these fouling and coking problems. A central concentrated spray nozzle (type: 2 US Gal 80 R) provided the best results and was selected for the optimisation study and the durability tests. With these different adjustments of the burner the combustion was optimised according to exhaust gas emissions (Liennard and Gandon, 1995a,b). Concerning atomizing oil burners (which flowrate is lower than 100 kg/h), the EN 267 European norm specifies bonds not to be overstepped. The burner must be optimised in respect with these values. Fig. 2 and Fig. 3 show the variations of CO and NOx in relation with the adjustment of: The position of the flame stabilizer,
the opening of the air valve, the temperature at the tip of the spray nozzle (from 80°C to 150°C) and the rape seed oil injection pressure. The optimal adjustment is obtained such as the CO rate is minimum when CO2 rate is maximum (we look for a complete combustion with minimum air excess to keep good efficiency). The values obtained in this case for the rape seed oil fuel are shown in Table 2. Table 3 shows the comparison between domestic fuel in the C22.0 as reference and results for rape seed oil in the modified C22.2.
3.3. Durability tests Grain drying: The C22.2 modified burner was used during 200 h at 260 kW for maize drying near the city of Bourges (Centre Region). Refined rape seed oil was used and a data logger was installed to monitor this test (Fig. 4). The quality of the grain was analysed by the laboratory of AGPM (Association Ge´ne´rale des Producteurs de Mais—Maize growers association). The results are very good in term of efficiency and cleanliness of the grain (Liennard and Gandon, 1996a,b). Central heating: The aim was to check the ability of the modified burner in heating application where numerous starting are occurring at various moment depending only on the weather and the behaviour of the users (see Fig. 5). Degummed rape seed oil was used during 2 months in the 175 kW boiler of one wing of the Town-hall of the city of Orle´ans (Liennard and Gandon, 1996a,b). Despite hundreds of startings the boiler walls remained clean and the nozzle tip was not coked up.
4. Conclusion This study has proved that degummed or refined rape seed oil can be used in adapted commercial burners with very good results in term of efficiency, gas emissions level and durability. The behaviour of rape seed oil is similar in burners and in diesel engines. Despite its high viscosity and its physical and chemical character-
G. Vaitilingom et al. / Industrial Crops and Products 7 (1998) 273–279
istics it is possible to modify and develop small to big size burners in respect with the interest of the users and the air quality regulation in force. This study has highlighted a new opening for rape seed oil and other vegetable oils, the use as biofuel in burners is far easier than in diesel powered vehicles in terms of technical or legislative constraint.
References Ryan, T.W., Callahan, T.J., Dodge, L.G., 1982. Characterization of vegetable oils for use as fuels in diesel engines. In: American Society of Agricultural Engineers (Ed.), Proceed-
.
279
ings of the International Conference on Plant and Vegetable Oils as Fuels, 2 – 4 August 1982, Fargo, ND, American Society of Agricultural Engineers, St. Joseph, MI, 70 – 81. Liennard, A., Gandon, M., 1995. Expe´rimentation de bruˆleurs a` huile de colza. Mesures et determination des caracteristiques necessaires au fonctionnement. CIRAD-SAR, report no. 1.95 (unpublished report), 102 pp. Liennard, A., Gandon, M., 1995. Expe´rimentation de bruˆleurs a` huile de colza. Objectifs: sechage et chauffage. CIRADSAR, report no. 83.95 (unpublished report), 68 pp. Liennard, A., Gandon, M., 1996. Expe´rimentation de bruˆleurs a` huile de colza. Fonctionnement d’un bruˆleur pour le sechage des graines. CIRAD-SAR, report no. 40.96 (unpublished report), 36 pp. Liennard, A., Gandon, M., 1996. Expe´rimentation de bruˆleurs a` huile de colza. Conclusions et perpectives. CIRAD-SAR, report no. 86.96 (unpublished report), 40 pp.