Rice Husk Blends Research Articles

Techno-economic analysis of sawdust and rice husk co-pyrolysis for bio-oil production

A techno-economic analysis of bio-oil production from co-pyrolysis of sawdust and rice husk blend was performed to assess the feasibility of scaling up the plant capacities. The analysis was conducted at plant capacities of 0.1 kg/h, 100 kg/h and 1000 kg/h in USD currency. Technology evaluation was based on an optimum bio-oil yield of 51.9 % and a blending ratio of sawdust to rice husk 50:50 using a fluidized bed reactor. Sensitivity analysis showed that operating labour costs, nitrogen costs and feedstock costs have a significant impact on the unit production cost of bio-oil. A plant capacity of 1000 kg/h appears to be more economical for bio-oil production at a nominal unit production cost of 0.052 USD/kg.

Study of co-pyrolysis kinetics, synergetic effects, and thermodynamics of coal and biomass blends

ABSTRACT The present work investigates the thermochemical conversion characteristics, reaction kinetics, and thermodynamic behavior of coal and biomass (Rice husk (RH)) blend pyrolysis in a TG reactor. Three different proportions of biomass (75, 50, and 25%) are blended with sub-bituminous Indian coal for the co-pyrolysis study. Pure coal and pure RH pyrolysis is characterized by three reaction stages, whereas the blended sample shows a four-stage thermal degradation reaction. A significant synergy is not found in the present study. Model-free techniques (FWO, KAS, and Starnik) are used to estimate the activation energy for various blending mixtures of the feed samples. The activation energy obtained for the equal mass ratio of coal and RH using the KAS, FWO, and Starnik methods is 61.45, 76.58, and 75.54 kJ/mol, respectively. The reaction order for coal: RH blend 25:75, 50:50, and 75:25 is estimated to be 4, 2.4, and 1.3, respectively. The favorable activation energy (Eα ) is found for the blending mixture of 50% coal and 50% RH. The positive value of ΔH indicates the endothermic nature of pyrolysis. The positive and negative values of ΔS indicate the complexity and nonspontaneous nature of coal and biomass blend pyrolysis. The average Entropy (ΔS) for an increasing % of coal is decreasing and the value comes to negative for 75% coal, indicating that thermal equilibrium is favorable for a higher % of coal.

Co-pyrolysis of cashew nut, coconut shells, and rice husk waste: kinetic and thermodynamic investigations

ABSTRACT Co-pyrolysis of low ash content of coconut shell (CNS) and cashew nuts shells (CCS), and high ash content rice husk (RH) blends was performed using thermal gravimetric analysis (TGA). RH was blended with both CCS and CNS at 0, 30, 60, and 100% RH by mass. Results showed that CCS and CNS have low ash contents of 2.7 and 1.5%, respectively, while RH has high ash content of 26.7% on dry basis. TGA under nitrogen gas study was carried out at three heating rates of 10, 15, and 20 K/min. It was observed that the increase of CCS/CNS increased decomposition rates of blends. For example, RH increased from 6 to 7.7%/min when CNS was added. Furthermore, addition of low ash content leads to high decrease of maximum decomposition rates compared to high-high or low-low ash blends. Synergistic analysis has found out that a positive effect is observed when CNS/CCS is added to RH. The decrease of maximum decomposition temperature of 60–63°C compared to other studies of 10°C for all low and 40° for all high ashes is of great advantage. Flynn-Wall-Ozawa (FWO), Kissinger-Akahra-Sunose (KAS), and DAEM kinetic model analysis for 0.1 ≤ α ≤ 0.75 were used between 315 and 840°C. FWO model gave activation energy of 85, 70, and 75 kJ/mol, for RH, CNS, and CCS, respectively. Addition of low ash content biomass reduced activation energy of RH, activation energy of RH was reduced from 85 to 72 kJ/mol when CNS was added. RH requires high energy than the rest, example, RH needed 66.29 kJ/mol of energy compared to 51% of CNS and 56 kJ/mol for CCS. The entropy results were negative which implies a different orientation of molecules from origin samples properties. The Gibbs-free energies were positive and thus non-spontaneous process. Empirical models generated using SB model indicated that kinetics depends on reaction order and acceleration mechanism rather than diffusion and nuclei growth. Kinetically, the blending of high and low ash content biomass leads to high decrease of operating temperature and activation energy compared to low-low or high-high ash content blends. It has been recommended to further study on quality and quantity of product from such blends and the possibility of pre-treatment methods such as microwaves to improve pyrolysis of such blend.

Impact of sodium silicate with normal pH on mechanical strength of rice husk blend geopolymer and its performance at various percentages

The stabilization capability of kaolin clay powder (KCP), Ordinary Portland cement (OPC) and rice husk ash (RHA) was scrutinized using laboratory scrutiny. This was meant at assessing the effect of KCP, OPC and RHA on the stabilization of three lateritic soils for use as sub-base pavement layer materials. Three soils (Soil A, B and C) were improved with various percentages (via weight of dry soil) at 0, 2, 4, 6, 8 and 10% for all stabilizing agents and compacted via BSL (British Standard light) energy. Their impacts were assessed on the strength physiognomies such as UCS (unconfined compressive strength), OMC (optimum moisture content), and California bearing ratio (CBR), and MDD (maximum dry density tests based on ASTM (American Standard Testing Materials) codes. The result reveals that MDD improved with increase in the quantities of all the additive (SSA, KCP and geopolymer) content, while OMC for KCP reduces from 18.65% at 0% to 14.02%. Both SSA and geopolymer increase from 18.65% at 0% to 18.86% and 22.20% at 10%.Similarly, it displays highest CBR of the soil from 10.88% at 0% to 12.84%, 112.95% and 144.45% for (SSA, KCP and geopolymer, this specify that lateritic soil treated with 2% stabilizer yielded CBR values of more than 405%.

Thermokinetics synergistic effects on co-pyrolysis of coal and rice husk blends for bioenergy production

In-depth thermodynamic and kinetic synergistic effects of the coal and rice husk blends on co-pyrolysis have been investigated for bioenergy production. The thermokinetic rate parameters were determined for chemical, one-dimensional diffusional, and phase interfacial reaction models especially when fitted to the Coats-Redfern method. The fitted models exhibited thermokinetic rate parameters. The thermogravimetric analysis in view of the thermodynamic parameters including enthalpy, Gibbs free energy, and entropy imparted the prominent degradation temperature ranges (Stage A: 200 °C–400 °C, Stage B: 410 °C–560 °C) for co-pyrolysis reactions of blends. The proportional increase of rise husk into coal for Stage A caused an increase in the apparent values of activation energy, enthalpy specifically for one-dimensional diffusional, and phase interfacial reaction models. In case of Stage B, the increasing share of rice husk into coal proved to be beneficial in decreasing values of activation energy and enthalpy. Positive synergies for 80:20 and 60:40 coal-rice husk blends were calculated. In addition to characterisation analysis of all samples; co-pyrolysis and co-gasification experiments were completed in a tubular fixed bed reactor at Stage B and onwards temperatures for synergised blends. The resultant co-pyrolysis biochar samples revealed honeycomb structure useful in adsorption applications. The gas chromatography-mass spectrometry analysis of the bio-oil yields 23% phenols, 11% acids, and methoxy phenols for the 60:40 coal-rice husk blend. The product gas composition of 2% H2, 14% CH4, and 4% CO2 for the 80:20 coal-rice husk blend increased to 3% H2, 12% CH4, and 5% CO2 for the 60:40 blend. The co-gasification process substantially increased the production of H2 up to 14%-17% when compared to co-pyrolysis results. The approach used in this study can be utilized to capitalize on synergy to enhance co-pyrolysis of appropriate blends and their products can be used in further future applications upon upgradation.

Cellulose Acetate of Rice Husk Blend Membranes: Preparation, Morphology and Application

Cellulose acetate blend membranes in this study synthesized from cellulose acetate (CA) of rice husk and NaA zeolites (Z) with N,N’-Methylene bis acrylamide (MBA) as cross-linker agent and gamma-rays from cobalt-60 source as a reaction initiator. Application of the membrane was carried out to increase the concentration of vetiverol in vetiver oil. The steps in this study were isolation the cellulose rice husk with alkali treatment, delignification, acetylation, preparation the cellulose acetate-NaA zeolites NaA-membrane by inverse phase technique, addition N,N’-Methylene bis acrylamide, and irradiation by gamma-rays. Swelling degree, crosslinking yield, tensile strength, membrane performance, FTIR, and SEM analysis were observed. The results obtained that the optimal irradiation dose for synthesis CA-Z-MBA membrane is 20 kGy. The CA-Z-MBA membrane has swelling degree of 4.44%, the tensile strength of 656.40 kg/cm2, and crosslinking yield of 6.61%. Performance of the CA-Z-MBA membrane reached the flux of 60.58 g/m2.h, and permeate concentration (CP) of 11.67%, the CP increase 5 times from 2.40% to 11.67%.

Study of Hydrothermally Lignite and Rice Husk blend: Thermogravimetric Analysis

The increased realization in greenhouse emission has encouraged to grow new technologies to accommodate the confinement and seizure of CO2. Keeping this situation, the thermal behaviour of lignite, Rice husk, besides their mergers throughout pyrolysis and combustion procedures, was examined in the study for their possible usage as a sustainable and substitute energy resource. The experiments were done in a thermo-gravimetric analyser at a heating rate of 40 °C/min and range from standard room-temp up to 950°C. These blends presented diverse ignition as well as combustion actions dependent on the proportion of rice husk and atmosphere (Oxy-fuel or Nitrogen). These investigational outcomes support to describe as well as expect the performance of lignite and rice husk blends in real applications.

The effects of hot briquetting on the coke strength in the biocoke making process with coal blending method

The biomass waste of rice husk and coconut shell in Indonesia reaches more than 15.8 million tons/year. In addition, the utilization of biomass waste has not been performed optimally. Rice husk and coconut shell are the biomass that can be processed as briquette material. This research aims to find the maximum temperature of hot briquette to generate the maximum coke strength from blending. First, the biomass waste was performed by a carbonization process at 400°C with a coal composition of biomass 95:5 wt%. The production of coke briquette used molasses binder 15 wt%. The hot briquette temperature variation was at 100 and 150°C with a briquette pressure of 200 kg/cm2. Coke briquette then was carbonized at 1100°C for 4 hours and followed by water quenching. The result indicates that hot briquette temperature depends on the type of biomass used. Coke briquette with a rice husk blend at 100°C and 150°C hot briquette temperature, respectively produced coke strength of 11.5 and 20.9 kg/cm2. Meanwhile, coke briquettes with coconut shell charcoal blend at 100°C and 150°C hot briquette temperature respectively produced coke strength of 15.8 and 10.8 kg/cm2.

The Pyrolytic Fuel Production From Nutshell-Rice Husk Blends and Determination of Engine Performance and Exhaust Emissions in a Direct Injection Diesel Engine

In this study, pyrolytic fuel from nutshell and rice husk blends was produced at 500°C temperature, 1 L/min gas flow rate and 10 °C/min heating rate. Pyrolytic fuel was experimented in a single cylinder, direct injection diesel engine with different engine speeds of 1750, 2000, 2250, 2750, 3000 rpm at wide open throttle. The blend of 10% pyrolytic fuel and 90% diesel (B10) and pure diesel were selected as test fuel. Test results showed that conversion efficiency increased with 15% rice husk and 85% nutshell blends compared to pure nutshell at 500°C temperature, 10°C/min and 1L/min gas flow speed. In addition, power output and brake torque decreased 10.20% with B10 compared to diesel. Specific fuel consumption (SFC) increased 28.42% with B10 compared to diesel. HC and CO reduced with pyrolytic fuel about 43.87% and 15.72% compared to diesel respectively. As a result, similar properties were seen between pyrolytic fuel and diesel. So, it was found that pyrolytic fuel could be efficiently used in diesel engines without detailed modification.

Effect of rice husk co-combustion with coal on gaseous emissions and combustion efficiency

ABSTRACTInvestigation on co-combustion of Lakhra coal and rice husk blends was carried out in a drop tube furnace to measure its impact on flue gas emissions and carbon burnout. According to experimental results, the emissions of NO and SO2 were higher in case of combustion of Lakhra coal compared to coal​–rice husk blends combustion. The emissions of CO decreased rapidly at higher furnace temperatures beyond 900°C. Minimum of CO emissions were nearly 45 ppm while SO2 and NO emissions were found to be 554 and 120 ppm, respectively, for 15% biomass blending ratio and at exit furnace temperature of 1000°C. The unburnt carbon was found to be reduced significantly with an increase in furnace temperature and blending ratio. The study has shown that blending of rice husk would be a useful option to minimize SO2 and NO emissions during combustion of Lakhra coal.

Chemically Treated Rice Husk Blends as Green Desiccant Materials for Industrial Application

AbstractThe use of rice husks (RHs), treated RHs, and blends thereof as desiccants was studied. Bare RHs, treated RHs, and blends were characterized, and their water absorbances compared. Acid‐treated RHs showed better moisture absorbance than alkali‐treated RHs and hence were used to prepare blends. Moisture absorption of RH materials and silica gel were compared. Blends with a higher content of acid‐treated RHs showed higher water and moisture absorbency. The moisture absorbency of the blends was enhanced, and they exceeded the silica‐gel limit at 48 h of exposure time. The higher absorbency in blends with higher contents of acid‐treated RHs is likely due to higher porosity and improved adhesion properties owing to surface OH groups. Moreover, RH blends require shorter regeneration times than silica gel.

Biofuel from Co-pyrolysis of Solid Tire Waste and Rice Husk

Abstract In this study the conversion of solid tire waste and rice husk into biofuels and chemicals by externally heated fixed-bed co-pyrolysis reactor have been taken into consideration. The solid tire waste and rice huskwere characterized through proximate and ultimate analysis, gross calorific values and thermo-gravimetric analysis to investigate their suitability as feedstock for this consideration. The collected solid tire waste chipped and then mixed with rice husk at different blends. The mixtures of solid wastes were fed into the reactor and the products were oil, char and gases. The liquid and char products were collected separately while the gas was flared into the atmosphere. The process conditions were varied by the percentage oftire in the blends at reactor temperature 450 °C. The variation of tire waste in feed blends was found to influence the product yields and feedstock to oil energy conversion efficiency (FOECE) significantly. The maximum liquid yields were 52wt% for50% tire and 50% rice husk blend at reactor temperature 450 °C for zeroN 2 gas flow, feed size 1800-2300 μm for rice husk and 2cm×1cm×1 cm for tire waste and running time 60 min. Liquid products obtained at these conditions were characterized by physical properties, chemical analysis and fractional distillation. The results show that it is possible to obtained liquid products that are comparable to petroleum fuels and valuable chemical feedstock from the selected wastes if the pyrolysis conditions are chosen accordingly.

A novel index for the study of synergistic effects during the co-processing of coal and biomass

In this study, synergistic interaction between coal and biomass and its intensity were investigated systematically using a low rank coal and its blends with different biomass samples at various blending ratios. The catalytic effects of minerals originated from biomass were also studied. It was found that some of the minerals existing in the ash derived from oat straw catalysed the combustions process and contributed to synergistic interactions. However, for the coal and rice husk blends, minimal improvements were recorded even when the biomass and coal blending ratio was as high as 30wt%. Biomass volatile also influenced the overall combustion performance of the blends and contributed to synergistic interactions between the two fuels in the blends. Based on these findings, a novel index was formulated to quantify the degree of synergistic interactions. This index was also validated using data extracted from literature and showed satisfactory correlation coefficients. It was found that at a blending ratio of 30wt% oat straw in the blend, the degree of synergistic interaction between coal and oat straw showed an additional SF value of 0.25 with non-catalytic and catalytic synergistic effect contributing 0.16 (64%) and 0.09 (36%) respectively. This index could be used in the selection of proper biomass and proper blending ratio for co-firing at coal-fired power stations aiming at improving the combustion performance of poor quality coals via enhancing synergistic interactions during co-processing.

Production of fuel briquettes from rice husk–lignite blends

In this study, a lignite sample from Afşin‐Elbistan area of Turkey was briquetted using rice husk as additive. The lignite and the rice husk were first briquetted separately without blending under pressures of 280, 555, 830, and 1110 MPa. Lignite–rice husk blends were prepared to contain 2, 5, 10, and 20 wt % rice husk as additive. The blends were also briquetted using three different binder materials (molasses, starch, and black liquor). Shatter index, compressive strength, and water resistance of the formed briquettes were determined and compared. Addition of rice husk into Afşin‐Elbistan lignite caused to decrease the water resistance, but improved the mechanical strength of the briquettes. Using binder materials affected both compressive strength and shatter index negatively. But the water resistance of the briquettes increased with increasing binder material concentration. Adding rice husk changed the combustion characteristics of Afşin‐Elbistan lignite considerably and shifted its burning profile to lower temperatures. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 742–748, 2017

Thermal behavior and kinetic analysis of co-combustion of waste biomass/low rank coal blends

The thermal decomposition behavior of Shenhua bituminous coal (SB), Rice husk (RH), Pine sawdust (PS) and their blend during combustion were investigated by using the thermal analysis method. The apparent kinetic parameters of combustion process were estimated by fitting the experimental data to the double parallel reactions nth order rate model. The results showed that the combustion characteristics of the two kinds of biomass residues with low degree of order are higher than that of bituminous coal. For blend of bituminous coal with biomass residues, the ignition performance could be improved by increasing content of biomass residues, but the comprehensive combustion characteristics first decreases and then increases, with its lowest value occurring at addition content of 60%. Meanwhile, through comparison between theoretically calculated and experimentally measured data, it is concluded that there’s a synergistic effect during combustion process of biomass and coal blend. Through kinetic analysis, it is found that the combustion processes of coal, biomass and their blends could be well represented by the double parallel reactions nth order rate model, and for the two stages in combustion, with an increase of biomass content both activation energies first decrease and then increase. Both stage activation energies of the RH blend have lowest value when RH ratio of 60% (first stage 140.2kJ/mol, second stage 136.9kJ/mol), but for the SP blend the first stage lowest activation energies was PS ratio of 20% with a value of 143.1kJ/mol and the second stage’s was a PS ratio 40% with a value of 143.9kJ/mol.

Development of Briquette from Coir Dust and Rice Husk Blend: An Alternative Energy Source

Biomass is one of the predominant renewable energy sources and the use of biomass for the energy generation has got much attention due to its environmental friendliness. Densification of coir dust into fuel briquette can solve waste disposal problem as well as can serve as an alternative energy source. The objective of this study was to investigate the possibility of producing briquette from coir dust and rice husk blend without binder. During this study, a briquetting experiment was conducted with different coir dust and rice husk blends (i.e. coir dust and rice husk ratio of 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100). Briquetting operation was performed using a die-screw press type briquetting machine. The briquettes were tested to evaluate their density, compressive strength, calorific value, burning rate and water vaporizing capacity and it was found that mixing ratio had a significant effect on the physical, mechanical and combustion properties of the coir dust-rice husk briquettes. Density, compressive strength and calorific value and water vaporizing capacity were increased with increasing mixing ratio while burning rate was decreased. Coir dust-rice husk briquettes with mixing ratio of 20:80 had higher density (1.413 g/cm3), compressive strength (218.4 N/cm2), calorific value (4879 kcal/kg), water vaporizing capacity (0.853 l/kg) and low burning rate (0.783 kg/hour) followed by the mixing ratio 40:60, 50:50, 60:40 and 0:100. The results indicate that coir dust and rice husk blend briquettes were found to have better overall handling characteristics over rice husk briquette. However, production of briquettes from coir dust and rice husk at mixing ratio of 50:50 was found to be more suitable for commercial application in terms of cost effectiveness.

Experimental Investigation of Thermal Characteristics of Kiwira Coal Waste with Rice Husk Blends for Gasification

Eminent depletion of fossil fuels and environmental pollution are the key forces driving the implementation cofiring of fossil fuels and biomass. Cogasification as a technology is known to have advantages of low cost, high energy recovery, and environmental friendliness. The performance/efficiency of this energy recovery process substantially depends on thermal properties of the fuel. This paper presents experimental study of thermal behavior of Kiwira coal waste/rice husks blends. Compositions of 0, 20, 40, 60, 80, and 100% weight percentage rice husk were studied using thermogravimetric analyzer at the heating rate of 10 K/min to 1273 K. Specifically, degradation rate, conversion rate, and kinetic parameters have been studied. Thermal stability of coal waste was found to be higher than that of rice husks. In addition, thermal stability of coal waste/rice husk blend was found to decrease with an increase of rice husks. In contrast, both the degradation and devolatilization rates increased with the amount of rice husk. On the other hand, the activation energy dramatically reduced from 131 kJ/mol at 0% rice husks to 75 kJ/mol at 100% rice husks. The reduction of activation energy is advantageous as it can be used to design efficient performance and cost effective cogasification process.

Study of Co-pyrolysis Characteristics of Lignite and Rice Husk in a TGA and a Fixed-Bed Reactor

Abstract Co-pyrolysis characteristics of lignite and rice husk blend were determined in TGA and a fixed-bed reactor. From TGA results, the weight loss rate of lignite and rice husk blend increases at 250–400°C. In a fixed bed at programmed temperature condition, the synergistic effect to produce more volatiles is appeared at 500–700°C, and the maximum synergistic effect exhibits with a rice husk blending ratio of 0.8. The gas yield of co-pyrolysis of lignite and rice husk blend was higher than that of the sum of lignite and rice husk individually. The kinetic studies were performed according to Coats–Redfern method for first-order reaction. It was found that the pyrolysis process of lignite and rice husk could be described by one first-order reaction and two consecutive first-order reactions, respectively. However, for lignite and rice blends, this process can be described by three consecutive first-order reactions. The estimated kinetic parameters, viz., activation energies and pre-exponential factors for lignite, rice husk and their blends, were found to be in the range of 63.5–477.8 kJ/mol and 1.4 × 103–6.5 × 1047 min−1, respectively.