Rice-Straw-Based Heat Generation System Compared to Open-Field Burning and Soil Incorporation of Rice Straw: An Assessment of Energy, GHG Emissions, and Economic Impacts

Abstract

<jats:p>Rice is a staple food crop, and its production generates large volumes of agricultural waste, rice straw. Several studies have proven that open-field burning and soil incorporation are unsustainable practices of managing rice straw, but remain as prevalent methods of treating and disposing of rice straw. An alternative solution is to harness the energy from rice straw via a small-scale heat conversion system for paddy drying applications, which can reduce rice grain post-processing costs and improve paddy storage conditions. This study investigated the energy flow, Greenhouse Gas (GHG) emissions, and cost of a small-scale rice-straw-based heat generation (RBHG) system using a downdraft furnace and a dryer simulator setup. The highest input energy and GHG emissions of 92% and 68%, respectively, were from the heat generation stage. The RBHG energy ratio was between 1.4 and 1.7, and the percent net energy was between 39 and 67%. The best case of RBHG offers a possibility of a net GHG avoided (−61 kg CO2-eq Mg−1), while the worst case (856 kg CO2-eq Mg−1) has a net GHG emission comparable with soil incorporation. The average total cost of RBHG is 0.096 USD kWh−1. Overall, RBHG technology has the potential to improve energy flow, GHG emissions, and the cost of rice production systems.</jats:p>

A Review of the Sustainable Utilization of Rice Residues for Bioenergy Conversion Using Different Valorization Techniques, Their Challenges, and Techno-Economic Assessment

“…A PFBD is a simple and low-cost system that consists of a drying bin, a blower and a furnace. Rice straw is used as fuel in the furnace, and the heat generated is used to dry the rice paddy [ 137 ].…”

“…For all the biomasses examined, the highest amount of organic carbon was obtained in RH biochar at 300 °C, reaching 58.74 wt%, while the highest organic conversion was observed in RH at 400 °C, reaching 56.62 wt%. The pre-treatment of biomass prior to pyrolysis using treatments that aid in demineralization and deoxygenation is one way to improve the quality of the pyrolysis products, which was proposed in [ 137 ]. Zhang et al [ 157 ] evaluated the effects of pre-treatments on the kinetics of pyrolysis and characteristics of the products using RH feedstock that was washed with acids and then torrefied.…”

CO2 Emissions from Fuel Consumption in the Logistic Stages of the Brazilian Bioethanol Supply Chain

“…Investigating the energy flow, GHG emissions, and cost of a small-scale rice-straw-based heat generation system, Ref. [15] used a downdraft furnace and a dryer simulator setup.…”

Environmental implications of reprocessing agricultural waste into animal food: An experience with rice straw and citrus pruning waste

“…Their application as building material was analysed by Dede et al (2021) as a growing media in green wall, Ricciardi et al (2020) as additives to produce thermal and acoustic insulation panels, Usubharatana and Phungrassami (2019) as thermal insulation material or Garas et al (2015) as sustainable light weight cementitious-straw bricks. Their application for energy purposes was analysed by Magnago et al (2020) for producing briquettes as source of heat, Migo-Sumagang et al (2020) for their harnessing for drying applications, Singh and Basak (2019) for comparing advanced techniques such as incineration, gasification or anaerobic digestion for electricity and ethanol production energy or Sagani et al (2019) for electricity generation from direct combustion of pruning residues. Their application for fuel for bio-refineries was analysed by Demichelis et al (2020) and Sreekumar et al (2020) for bioethanol production, Im-orb and Arpornwichanop (2020) for methanol and bio-oil production or González et al (2011) for pulping and combustion processes.…”