Combustion performance of Jatropha curcas L. residues in a biomass burner with continuous feeding system

ABSTRACT

Combustion of Jatropha curcas L. press cake, seed shells and shell/hull-pellets as biofuels using an automatic biomass burner was investigated for 36 h under continuous operation. Temperatures in the combustion chamber and of the flame, exhaust gas and ash were evaluated. Thermal efficiency of press cake, seed shells and shell/hull-pellets was determined to be 93.1, 95.4 and 94.1%, respectively. CO₂ content in the exhaust gas was measured as 7.1, 13.3 and 11.8% vol., while the content of CO was 1.9, 4.6 and 2.8% vol., respectively. The amount of remaining ash was 13.1, 11.8 and 10.6%, respectively. In all ashes, the major nutrients for fertilizers such as potassium, phosphorus, calcium and magnesium exceeded the minimum threshold of German fertilizer regulation. A high chlorine content was detected in the ashes. Contents of other minerals (iron, titanium and manganese) and heavy metals such as nickel were found to be lower than the maximum threshold. However, the chromium content exceeded the threshold. The content of heavy metals should be reduced before utilizing the ash as fertilizer.

KEYWORDS:

• Emission
• flue gas
• heating
• solid biofuel
• wood pellet boiler

Acknowledgements

The authors thank Christian Raichle and Sebastian Awiszus for their technical assistance during field measurements. The proofreading of this manuscript by Sabine Nugent, Peter and Kate Lawrence is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Bundesministerium für Bildung und Forschung (BMBF) [grant number 033R069A].