Development and Validation of Mass Reduction Prediction Model and Analysis of Fuel Properties for Agro-Byproduct Torrefaction

Abstract

Global warming is accelerating due to the increase in greenhouse gas emissions. Accordingly, research on the use of biomass as energy sources, is being actively conducted worldwide to reduce CO2 emissions. Although the production of agro-byproducts is vast, their utilization for energy production has not been fully investigated. This study suggests an optimal torrefaction process condition for agro-byproducts, such as grape branch and perilla, that have moisture content but low calorific values. To determine whether these agro-byproducts can be used for energy sources as substituents of fossil fuels, a mass reduction model was established and validated via experimental results. Thermogravimetric analysis was conducted for different heating rates, and the activation energy and frequency factor were derived through the analysis. The model was developed by changes in rate constants, moisture content, ash content, and lignocellulose content in biomass. To ascertain the optimal torrefaction conditions, fuel characteristic analysis and changes in energy yield of torrefied grape branch and perilla were investigated. The optimal torrefaction conditions for grape branch and perilla were 200 °C for 40 min and 230 °C for 30 min, respectively. The comparison result of the experiment and simulation at the optimum conditions of mass reduction were 1.42%p and 1.51%p, and 15 °C/min and 7.5 °C/min at heating rate, respectively.

Developing a Proximate Component Prediction Model of Biomass Based on Element Analysis

“…AAE and ABE were expressed as shown in Equations ( 3) and ( 4). The coefficient of determination value (R 2 ) was calculated as shown in Equation ( 5) to determine the degree of goodness of the proposed correlation [46,63,64].…”

Identification of differences and comparison of fuel characteristics of torrefied agro-byproducts under oxidative conditions

“…Devices for collecting agricultural by-products have been developed to use this biomass [ 2 ]. Anaerobic digestion has been used to produce biogas, and pelletizing [ 3 , 4 ]. Thermochemical pretreatments [ [3] , [4] , [5] , [6] ] have been tested to produce solid fuels.…”

“…Anaerobic digestion has been used to produce biogas, and pelletizing [ 3 , 4 ]. Thermochemical pretreatments [ [3] , [4] , [5] , [6] ] have been tested to produce solid fuels. However, compared with solid fossil fuels, many agricultural byproducts are typically not utilized due to their hydrophilic nature, low energy content, and challenges associated with storage [ [7] , [8] , [9] , [10] , [11] , [12] , [13] ].…”

“…Torrefaction is the process of heat-treating biomass at temperatures ranging from 200 to 300 °C in an oxygen-deficient environment. The procedure can attain the following benefits: a relatively higher calorific value; hydrophobic properties of the product; more extended storage; and ease of transport [ 3 , [14] , [15] , [16] , [17] ]. However, maintaining oxygen-deficit conditions and mass loss during the process have been identified as shortcomings.…”

Evaluation of the Optimal Conditions for Oxygen-Rich and Oxygen-Lean Torrefaction of Forestry Byproduct as a Fuel

“…In addition, in the recent revision of the ⸢Act on the Promotion of the Development, Use, and Diffusion of New and Renewable Energy⸥ and under Article 23-2: a mandatory system for mixing new and renewable energy fuels in 2022, only unused forest biomass burning facilities received a renewable energy certificate (REC) weight of 2.0, which was considered an advantage for unused forest biomasses [11,12]. However, disadvantages associated with agricultural and forestry biomasses include a relatively low calorific value compared with that of coal and difficulty in storage and transportation owing to their hygroscopic properties and low bulk density [13]. Furthermore, during disposal and processing, concerns arise regarding the odor, emission, and leaching of hazardous components [14].…”