The Influence of Corn Straw Extrusion Pretreatment Parameters on Methane Fermentation Performance

Karol Kupryaniuk; Tomasz Oniszczuk; Maciej Combrzyński; Wojciech Czekała; Arkadiusz Matwijczuk

doi:10.3390/ma13133003

The Influence of Corn Straw Extrusion Pretreatment Parameters on Methane Fermentation Performance

Materials (Basel). 2020 Jul 6;13(13):3003. doi: 10.3390/ma13133003.

Authors

Karol Kupryaniuk¹, Tomasz Oniszczuk¹, Maciej Combrzyński¹, Wojciech Czekała², Arkadiusz Matwijczuk³

Affiliations

¹ Department of Thermal Technology and Food Process Engineering, University of Life Sciences in Lublin, Głęboka 31, 20-612 Lublin, Poland.
² Institute of Biosystems Engineering, Poznań University of Life Sciences, Wojska Polskiego 50, 60-627 Poznań, Poland.
³ Department of Physics, Lublin University of Life Sciences Akademicka 13, 20-950 Lublin, Poland.

Abstract

The aim of the study is to determine the energy consumption of the extrusion-cooking process of corn straw under various conditions (screw speed, moisture content), water absorption measurements and water solubility indices as well as biogas efficiency evaluation. The extrusion-cooking of corn straw was carried out using a single screw extruder with L/D = 16:1 at various rotational screw speeds (70, 90, and 110 rpm) and with various initial moisture content of raw material (25 and 40%). Prior to the process, the moisture content of the raw material was measured, and next, it was moistened to 25 and 40% of dry matter. For example, at 70 rpm extruder screw speed, the temperature range was 126-150 °C. Energy consumption of straw pretreatment through extrusion-cooking was assessed in order to evaluate the possibility of using the process in an agricultural biogas plant. Biogas and methane efficiency of substrates after extrusion was tested in a laboratory scale biogas plant and expressed as a volume of cumulative methane production for fresh matter, dry matter, and dry organic matter. Pretreated corn straw moistened to 25% and processed at 110 rpm during the extrusion-cooking processing produced the most advantageous effect for methane and biogas production (51.63%) efficiency as compared to corn straw without pretreatment (49.57%). Rotational speed of the extruder screw influenced biogas and methane production. With both dry matter and dry organic matter, the increase of rotational speed of the extruder screw improved the production of cumulated biogas and methane. Pretreatment of corn straw has a positive effect on the acquisition of cumulated methane (226.3 Nm³ Mg^-1 for fresh matter, 243.99 Nm³ Mg^-1 for dry matter, and 254.83 Nm³ Mg^-1 for dry organic matter). Preliminary analysis of infrared spectra revealed changes in the samples also at the molecular level, thus opening up the possibility of identifying marker bands that account for specific degradation changes.

Keywords: FTIR spectra; corn straw; extrusion-cooking; pretreatment biogas production; renewable energy.