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

Abstract

<jats:p>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.</jats:p>

Physical Properties, Spectroscopic, Microscopic, X-ray, and Chemometric Analysis of Starch Films Enriched with Selected Functional Additives

“…The changes are also discernible at the molecular level in the form of changes in the IR spectra. This is attributable both to the amount of the additive used and the rotational speed of the extruder device [27,36]. Evidently, all the tested samples contain a low content of water molecules.…”

The Influence of the Pressure-Thermal Agglomeration Methods of Corn Bran on Their Selected Physicochemical Properties and Biogas Efficiency

“…The extrusion process is successfully used in the treatment of typical waste lignocellulosic materials such as straw or hay. The application of the extrusion-cooking technique in the processing of lignocellulosic materials in the form of corn or cereal straw allowed for the increase the biogas efficiency by up to 70% compared to non-extruded samples [38]. By means of the conducted research, we were able to obtain new knowledge as to whether the additional energy expenditure incurred for the processing of bran has economic justification.…”

Effect of extrusion-cooking conditions on the physical properties of Jerusalem artichoke straw

“…Energy consumption, expressed as specific mechanical energy (SME, kWh kg -1 ) was calculated by taking into account the engine load, the extruder working parameters and the process efficiency of each test according to the formula (Combrzyński et al, 2020):…”

“…As follows from the literature results, the inclusion of a pretreatment stage can improve the efficiency of biogas production by over 90% for raw materials such as grass, maize straw, or wood. Several distinct methods of lignocellulosic biomass pretreatment can be distinguished, including chemical, biological, mechanical, and extrusion-cooking (Robak and Balcerek, 2017;Kupryaniuk et al, 2020). It is impossible to identify the most effective method because the results are strongly dependent on the particular type of lignocellulosic biomass used in the given process.…”