Agricultural Processing Residues Research Articles

The spatial distribution characteristics of the biomass residual potential in China

Biomass energy as a kind of renewable energy would be one of the industry's future development direction. As a high energy consumption country, China is urgent need of developing the renewable energy. Understanding the distribution and components of biomass could be beneficial to guide the utilizing technologies and investment strategy of biomass residual. The comprehensive statistical methods were applied to calculate the potential biomass residual of each provinces in China. The results show that (1) Nationwide, the residues biomass of agricultural, forest, and urban waste accounted for 64.16%, 10.88%, and 24.96% of total biomass residual, respectively. The intensity of agricultural, forest, and urban waste biomass residual were 1.89, 0.32, and 0.74 PJ per km2 year, respectively. (2) The agricultural biomass residual in eastern China was more abundant than that in western China. The straw residues, agricultural processing residues, livestock manure and pruning residues from permanent orchard respectively shared 32.24%, 10.62%, 56.0%, and 1.13%. (3) The stem wood with its intensity 0.29 PJ per km2 year was major contributor of forest biomass residual (with its intensity 0.32 PJ per km2 year). The forest biomass residual in northern and southern China was larger than that in eastern and western China, but the intensity of forest biomass residual in southern China was larger than that in the other provinces. (4) The intensity of forest biomass was 0.74 PJ per km2 year, which was mainly contributed by urban greenery management outside forests (0.736 PJ per km2). The intensity of urban biomass residual in eastern and southern China was usually larger than that in northern and western China.

Emission Behaviors of Submicron Particles (PM1) Generated by the Combustion of Sesame Stalk after Combined Water Washing and Carbonization Pretreatment

Pretreatment before biomass combustion is significant for its efficient utilization and that combined water washing and carbonization can be efficient. An agricultural processing residues sesame stalk was selected and carried out two pretreatments separately, i.e., water washing-torrefaction (W-T) and torrefaction-water washing (T-W), to explore the effect on the fuel properties, combustion characteristics and particulate matter (PM) emission. The obtained biochar was also combusted under air and oxy50 (CO2:O2 = 50:50) conditions for the sake of investigating the effect of pretreatment and combustion atmosphere. The results indicate that, W-T and T-W both not only have great effect on the improvement of fuel properties but also reduce the content of water-soluble elements like K, Cl, etc. Due to the difference in hydrophobicity, the biochar obtained by W-T have the optimal fuel properties. At the same time, the pretreatment also hinder the combustion in a certain extent in which the comprehensive combustion characteristics (SN) show a downward trend. Furthermore, both two pretreatments have obvious benefit on the reduction of PM1 emission and W-T have the best effect related to the higher removal efficiency of inorganic elements (especially K + Na + Cl + S). Under oxy50 condition, the oxygen concentration and combustion temperature is higher, improving the sulfation of K and vaporization of Ca, P and Mg which result in weakening in the pretreatment reduction effect on PM1 emission.

Intensification of pre-treatment and fractionation of agricultural residues

Lignocellulose biomass is a unique renewable and sustainable source that can be used in energy generation, production of transport fuels and in chemical industries to replace petroleum-based resources. However, due to its recalcitrance to chemical and enzyme breakdown, it needs to be pre-treated prior to processing. In this study, ultrasound assisted ozone was used to pre-treat the agricultural processing residues corn cob and spelt husk. Following organosolv fractionation, about 90 % and 94 % of lignin with high purity (95 %) were recovered for corn cob and spelt husk with guaiacyl-syringyl lignin the major fraction from corn cob and guaiacyl lignin from spelt husk respectively. In addition, cellulose pulp of 83.6 % and 85.2 % with 78 % purity were recovered for corn cob and spelt husk respectively with a 19 % decrease in cellulose crystallinity and 17 % decrease in degree of polymerization (DP). Thus, the improved quality separation of biomass components will enhance downstream conversion to value added products thereby improving the sustainability and cost effectiveness of the process.

Experimental study on drying characteristic of corncob in plate rotary heat exchanger

AbstractAgricultural processing residues, such as corncobs, can be used as good biomass pellet fuels. To thoroughly study the drying characteristics of corncobs in a rotary dryer, a plate rotary heat exchanger (PRHE) was applied to the drying of corncob particles in the present article. The PRHE had an inner diameter of 273 mm and a length of 1,000 mm. Twelve rectangular plates were designed as the heating plate. The influence of several parameters on the corncob drying characteristics was experimentally investigated. The results indicated that the drying rate increased with increasing corncob initial moisture content, increasing dryer heating power, and decreasing corncob particle diameter. Then, based on the experimental results, two exponential correlations were regressed by the least squares method. Both the correlations were valid and the three‐parameter model had a better fitting degree than the two‐parameter model. The trend in the drying rate of corncobs in PRHE clearly included a rising‐rate stage and a falling‐rate stage. The Taguchi approach was employed to study the impact degree of different factors on the maximum drying rate, which showed that initial moisture content had the largest impact degree, followed by heating power; furthermore, the effect of particle diameter was not significant.Practical applicationsPromoting the use of biomass energy is an effective means to respond to the climate change challenge. As one of the major agricultural processing residues in mainland China, corncob can be processed into biomass pellet fuels with easy storage, high energy density, and low pollutant emissions after crushing, drying and compression molding. For the sake of settling the uncontrollable limitations of traditional open air‐drying method for corncob, author developed a new type of plate rotary heat exchanger (PRHE). By investigating the drying characteristics of corncob in PRHE with various experimental conditions, research findings provide references for the development and large‐scale industrial application of plate rotary drying technology in the drying of agricultural processing residues in the future.

Thermo-physical characterization of torrefied fuel pellet from co-pelletization of canola hulls and meal

Agricultural processing residues, as renewable sources of energy, can be converted to value-added products such as fuel pellets with the wide applications in the production of heat and power. In this research, densification/torrefaction of canola meal and canola hull was investigated. A bench-scale extruder was used for densification of canola hull and canola meal. Then, to increase the hydrophobicity and heating value of pellets, they were torrefied. For pelletization of canola meal, an increase in canola meal to water mass ratio resulted in an increase in the mechanical strength of pellets. Canola meal was also used to facilitate pelletization of canola hull. Co-pelletization of canola hull with canola meal was successful for canola hull mass percentage up to 60 wt% in the feedstock. In general, torrefied pellets showed lower moisture adsorption (up to 59%), higher carbon content (in the range of 21–25%), lower oxygen content (35–46%), and higher heating value (up to 22%) compared with their respective precursors. To study the effects of operating conditions and additives, different characterization techniques were used to evaluate the thermal, chemical, mechanical, and physical properties of pellets. Synchrotron-based computed tomography showed that after torrefaction, porosity increased by 10% for pellets from canola meal and increased by 22–30% for pellets prepared by co-pelletization. Addition of alkali lignin to canola meal precursor helped to increase the mechanical strength of torrefied pellet produced from canola meal. The use of binders such as alkali lignin and crude glycerol had no effect on the relaxed density of torrefied pellets and resulted in higher moisture adsorption.

Present Status and Problems in Waste Disposal and Application of Technologies to the Agricultural Processing Residues

Present Status and Problems in Waste Disposal and Application of Technologies to the Agricultural Processing Residues