Pyrolysis Of Rice Straw Research Articles

Simultaneous thermogravimetric and mass spectrometric monitoring of the pyrolysis, gasification and combustion of rice straw

Energy valorization of rice straw is possible by thermal conversion. The aim of this paper was to study the emissions throughout heating of rice straw under seven different atmospheres (simulating combustion, gasification and pyrolysis). For this purpose, combustion, gasification and pyrolysis of rice straw were studied by simultaneous TG/MS dynamic runs at 15 °C min−1. Results showed that a partially inert atmosphere is more advisable from an environmental point of view due to the lower emission of contaminants.

Batch Pyrolysis of Acid-Treated Rice Straw and Potential Products for Energy and Biofuel Production

Purpose Rice straw is an abundant but largely unutilized biomass. If rice straw’s ash content could be reduced by pretreatment, it could be pyrolyzed into energy-dense, soil-enriching products. This paper investigates if acid-pretreatment of rice straw before pyrolysis could improve the char, bio-oil or gas products of pyrolysis.

Microwave pyrolysis of rice straw to produce biochar as an adsorbent for CO2 capture

The CO2 adsorption on biochar produced by microwave pyrolysis of rice straw was investigated in this study. A microwave power level of 200 W and a maximum temperature of approximately 300 °C would be the optimal parameters to adsorb the most CO2. The CO2 adsorption capacity was up to 80 mg/g at 20 °C. The adsorption capacity decreased at higher power levels and temperatures possibly owing to the pore destruction. The CO2 adsorption capacity was highly correlated with the specific surface area of biochar. The conventional pyrolysis at 550 °C was optimal to produce the biochar absorbing the most CO2 which, however, was still lower than that of the biochar produced by microwave pyrolysis by about 14%. Low activation energy implies that CO2 adsorption on the biochar is physisorption. The ratio of CO2 quantity versus solid product quantity can almost match the CO2 adsorption capacity of the biochar produced at 200 W microwave power levels, so the microwave pyrolysis without further processes to meet the zero emission of CO2 should be workable. Compared with conventional pyrolysis, microwave pyrolysis could produce the biochar with lower time, cost, and energy consumptions.

Enhancing the quality of bio-oil and selectivity of phenols compounds from pyrolysis of anaerobic digested rice straw

This study investigated the thermal decomposition characteristics and pyrolytic products of anaerobic digested rice straw (ADRS) by thermogravimetric (TG) and pyrolysis–gas chromatograph/mass spectrometry (Py-GC/MS) analysis. Compared with the raw rice straw (RS), the thermal decomposition temperature of ADRS was shifted to higher temperature zone and the second decomposition zone of cellulose (Toffset(c)−Tpeak) became narrower (14°C less), which indicated that the composition of rice straw were changed significantly by the anaerobic digestion pretreatment. Py-GC/MS analysis showed that the quality of the bio-oil and the selectivity of pyrolytic products could be obviously improved by anaerobic digestion. The total yields of alcohols, acids, aldehydes, furans, anhydrosugars, and ketones pyrolysis substances decreased, while the yield of phenols increased. The yield of 4-Vinylphenol (4-VP) increased from 29.33%, 8.21% and 5.76% to 34.93%, 12.46% and 7.68% at 330, 450 and 650°C, respectively, after anaerobic digestion.

Value addition to rice straw through pyrolysis in hydrogen and nitrogen environments

Pyrolysis of rice straw has been carried out under hydrogen atmosphere at 300, 350, 400 and 450°C and pressures of 1, 10, 20, 30 and 40bar and in nitrogen atmosphere, experiments have been carried out at the same temperatures. It has been observed that the optimum process conditions for hydropyrolysis are 400°C and 30bar pressure and for slow pyrolysis, the optimum temperature is 400°C. The bio-oil has been characterised using GC–MS, 1H NMR and FT-IR and bio-char using FT-IR, SEM and XRD. The bio-oil yield under hydrogen pressure was observed to be 12.8wt.% (400°C and 30bar) and yield under nitrogen atmosphere was found to be 31wt.% (400°C). From the product characterisation, it was found that the distribution of products is different for hydrogen and nitrogen environments due to differences in the decomposition reaction mechanism.

Cogasification of typical plastics and rice straw with carbon dioxide

Cogasification of high‐calorific‐value plastics with biomass can effectively improve the quality of gas production and utilize plastic waste as a resource. In this study, the gasification characteristics of rice straw with three types of typical plastics in a carbon dioxide (CO2) atmosphere were evaluated, and the relevant kinetic parameters were calculated using a thermogravimetric and differential thermal analyzer (TG/DTA). In the case of gasification of plastics only, the integral difference in TG (ΔM) showed that polyethylene terephthalate (PET) with poor thermoplasticity promoted the pyrolysis of rice straw, whereas polyethylene (PE) with good thermoplasticity hindered it. Furthermore, the effects were strengthened with increasing ratio of plastics/rice straw. In the case of cogasification of plastics and rice straw, the mass loss of mixture is higher than the linear sum of the parent fuels. The cogasification of plastics and rice straw had a synergistic effect; the plastic content had a greater effect on ΔM. In this study, all the maximal ΔM was more than 10%. The kinetic analysis showed that the synergistic effect of the plastics and rice straw reduced the activation energy of the gasification reaction. The minimal activation energies of rice straw with PE, poly(vinyl chloride), and PET in the cogasification were 32.52, 59.65, and 65.77 kJ/mol, respectively, all of which were less than the weighted summation of the individual activation energies of the plastics and rice straw. © 2014 American Institute of Chemical Engineers Environ Prog, 2014 34: 789–794, 2015

Influence of Chemical Treatment on Rice Straw Pyrolysis by TG-FTIR

The influence of treatment on pyrolysis characteristic and the products evolution performance of rice straw had been investigated by thermogravimetric analyzer coupled with Fourier transform infrared spectrometry(TG-FTIR). The results showed that after chemical treatment such as acid and alkali treatment, the initial pyrolysis temperature and the maximum weight loss temperature shifted to high temperature zone, the maximum weight loss rate increased, and the shoulder peaks of DTG went to fade. The ranges of E (activation energy), which was calculated through Flynn-Wall-Ozawa method, were 198∼219kJ/mol, 184∼216kJ/mol, 175∼205kJ/mol, 184∼216kJ/mol, and 205∼230kJ/mol for raw-RS, H2SO4-RS, H3PO4-RS, HCl-RS, and NaOH-RS, respectively. The thermodynamic parameters of ΔH, ΔG, andΔS were calculated at the DTG peak temperature. After chemical treatment, most of alkali metals were removed, and the absorbance intensities of CO2 and CO decreased comparing to that of raw sample, while the evolution of pyrolysis products including C-H, C-O-H, and C–O–C functional groups were enhanced through acid. Particularly, C=O functional groups were decreased through acid, but increased through NaOH.

Catalytic pyrolysis of rice straw and product analysis

Catalytic pyrolysis of rice straw and product analysis

Slow pyrolysis of rice straw: Analysis of products properties, carbon and energy yields

Among many uses of rice straw, application of its biochar from pyrolysis to the soil is receiving greater interest for increased crop productivity and sequestration of CO2. This study investigated slow pyrolysis of rice straw at 300-700°C to characterize the yields and detailed composition of the biochar, bio-oil and non-condensable gases. Biochar was analyzed for pH, microscopic surface area and pore volume distribution. Although the mass yield for the organic fraction was only about 25% above 500°C, biochar was the primary product of pyrolysis containing 40% of energy and 45% of carbon from the straw. The utilization of by-products (bio-oil and gases) as energy resources was essential, since the sum of energy yield was about 60%. The gases could be burned to produce the heat for an auto-thermal pyrolysis process, but the heat balance was significantly influenced by the moisture content of the raw material.

Effect of Dolomite on Pyrolysis of Rice Straw

A study of catalytic pyrolysis on rice straw was carried out in a fixed-bed reactor. The objectives were to determine the effect of dolomite catalyst on the distribution of product yield and bio-oil characterization. The non-catalytic and catalytic process of rice straw was performed at the optimum conditions. The chemical characterization studies of uncatalysed bio-oil derived from pyrolysis of rice straw reflect a considerable amount of carbonyl and oxygenated compound, resulting in higher oxygen content in elemental composition. In the presence of the dolomite catalyst, the yield of bio-oil was markedly reduced and so was the oxygen content of the bio-oil itself. The product yields and quality of the resultant bio-oil were significantly affected by the use of dolomite catalyst.

Selective Production of 4-Vinylphenol by Fast Pyrolysis of Herbaceous Biomass

4-Vinylphenol is an important chemical that can be used as the monomer for the production of poly(4-vinylphenol) (PVPh). Currently, 4-vinylphenol was prepared by the dehydrogenation of 4-ethylphenol over chromia/alumina catalyst at 600 °C. In this study, a low-cost process involving low-temperature fast pyrolysis of biomass without any catalyst was developed to selectively produce 4-vinylphenol. Pyrolysis gas chromatography/mass spectrometry (Py–GC/MS) was used for the fast pyrolysis of bagasse, cornstalk, bamboo, rice husk, rice straw, cotton straw, and poplar wood to investigate the effects of different materials on the selectivity of 4-vinylphenol. It was found that some of the herbaceous materials, such as bagasse, cornstalk, and bamboo, were suitable for the production of 4-vinylphenol, whereas woody materials were not applicable. The effects of temperature on 4-vinylphenol production were also investigated. 4-Vinylphenol contents of up to 7 and 20 wt % were achieved at 300 °C from bagasse and bagass...

Microwave Irradiation Pyrolysis of Rice Straw in Ionic Liquid ([Emim]Br)

The pyrolysis reaction of rice straw under microwave irradiation in bromide 1-ethyl-3-methyl imidazole ([Emim]Br) ionic liquid (IL) was investigated in this work. The effects of reaction temperature, mass ratio of IL to straw, reaction time, and microwave irradiation power on the yield of bio-oil were considered. An orthogonal experimental method was adopted to obtain the optimal technological conditions for pyrolysis: a reaction temperature of 160 °C, a mass ratio of IL to straw of 2:1, a reaction time of 15 min, and a microwave irradiation power of 700 W. The yield of bio-oil reached 28.2% at optimum conditions. The percent recovery of IL ranged from 84% to 87%. The recycled IL could be reused as straw pyrolysis solvent and did not affect the bio-oil yield because its structure was not damaged after being used in pyrolysis as a solvent.

Microwave pyrolysis of rice straw: Products, mechanism, and kinetics

Rice straw is an abundant resource for the production of biofuels and bio-based products. How to convert the recalcitrant lignocellulose effectually is a critical issue. The objective of this study was to investigate the products, mechanism, and kinetics of rice straw pyrolysis by using microwave heating. The highest energy densification ratio of solid residues was achieved at the microwave power level of 300 W. The atomic H/C and O/C ratios of solid residues were much lower than those of rice straw. The primary components of gaseous product were CO, H2, CO2, and CH4, whose molecular fractions were 57%, 21%, 14%, and 8%, respectively. The more gaseous product and the less solid residues were obtained at higher microwave power levels, while the liquid production remained the same and showed a maximum of about 50 wt.%. The kinetic parameters of rice straw pyrolysis were increased with increasing microwave power level.

Pt/Al2O3-catalytic deoxygenation for upgrading of Leucaena leucocephala-pyrolysis oil

The aim of this study was to improve the quality of bio-oil produced from the pyrolysis of Leucaena leucocephala trunks via catalytic deoxygenation using Pt/Al2O3 (Pt content=1.32% (w/w)). The minimum molar ratio of oxygen/carbon (O/C) at 0.14 was achieved when the amount of catalyst was 10% (w/w, bio-oil) and was applied under 4 bar of initial nitrogen pressure at 340°C for 1h. The reaction mechanism of the catalytic deoxygenation, in terms of reforming, water-gas shift and dehydration reactions, was proposed. To consider the effect of different biomass types on the efficiency of catalytic deoxygenation, the bio-oils obtained from the pyrolysis of sawdust, rice straw and green microalgae were likewise evaluated for direct comparison.

Conversion of Rice Straw to Bio-Fuel by Pyrolysis in Molten KCl-LiCl

The objective of this study was to provide background date on rice straw pyrolysis in molten KCl(40mol%)-LiCl(60mol%). The effects of pyrolysis temperatures and sweep gas flow rates on the pyrolysis products yields and their chemical compositions were studied. The temperatures of pyrolysis and sweep gas flow rates were varied in the range of 380°C -540°C and 60L/h-260L/h, respectively. The compositions of gaseous products were analyzed by gas chromatography, and that of bio-oil obtained was investigated using gas chromatography-mass spectroscopic(GC-MS) technique. The yield of gaseous products increases with the increasing temperature, the char yield has demonstrated a downtrend, and the maximum yield of bio-oil is up to 15.43 wt.% at 460°C. The yield of char decreases with the sweep flow rate, the gaseous has a minimum yield at 100L/h, and the maximum yield of bio-oil is 15.43wt.% at 100L/h .The main gaseous products are CO, CO2 , H2 and CH4. Ketones and phenols are the main compounds in the bio-oil, the presence of molten inhabites their formation, and promotes the production of furfural. The bio-oil attained from pyrolysis is a potential source of renewable fuel and chemical feedstock.

Sensitivity analysis of three-parallel-DAEM-reaction model for describing rice straw pyrolysis

The three-parallel-DAEM-reaction model was used to study the slow pyrolysis kinetics of rice straw based on thermogravimetric analysis (TGA) data. The kinetic parameters of the model were calculated using the pattern search method. A comparison between the predicted DTG data and experimental values showed good agreement. The influences of the kinetic parameters on the model for describing the experimental data of rice straw were analyzed by means of local parametric sensitivity analysis. The results indicated that the frequency factor and the mean value of the activation distribution for cellulose decomposition affect the model more strongly than other parameters, followed by the corresponding parameters for hemicellulose and lignin. The sensitivity of the model to the standard deviations of the activation energy distributions for all pseudocomponents is very slight.

Chemical characterization of rice straw-derived biochar for soil amendment

Pyrolysis of rice straw to create biochar for soil amendment appears to be a promising method to address concerns with regard to improving soil fertility, increasing Carbon storage and decreasing Green House Gas emissions. However, the ability of rice straw-derived biochar to affect these factors might vary depending on its characteristics. It is therefore essential to investigate the properties before large-scale application of rice straw-derived biochar. In this study, rice straw-derived biochars produced at different temperatures (300, 400, 500, 600 & 700 °C) and residence time (1, 2, 3 & 5 h) were characterized using a suite of analytical techniques. Results showed that pyrolysis temperature had a greater influence than residence time on the chemical composition and structure of rice straw-derived biochar produced at low heating rate. The rice straw-derived biochars especially produced at 400 °C had high alkalinity and cation exchange capacity, and high levels of available phosphorus and extractable cations. These properties indicate potential application of rice straw-derived biochar as a fertilizer and soil amendment. Fourier transform infrared spectra showed that higher pyrolysis temperatures promote condensation reactions. Rice straw-derived biochars contained turbostratic crystallites at 400 °C, and displayed a high level of aromatization at 500 °C. Increasing charring temperature will increase the aromaticity of biochar, and might include its recalcitrance.

Evaluation of the porous structure development of chars from pyrolysis of rice straw: Effects of pyrolysis temperature and heating rate

The effects of pyrolysis temperature and heating rate on the porous structure characteristics of rice straw chars were investigated. The pyrolysis was done at atmospheric pressure and at temperatures ranging from 600 to 1000°C under low heating rate (LHR) and high heating rates (HHR) conditions. The chars were characterized by ultimate analysis, field emission scanning electron microscope (FESEM), helium density measurement and N2 physisorption method. The results showed that temperature had obvious influence on the char porous characteristics. The char yield decreased by approximately 16% with increasing temperature from 600 to 1000°C. The carbon structure shrinkage and pore narrowing occurred above 600°C. The shrinkage of carbon skeleton increased by more than 22% with temperatures rising from 600 to 1000°C. At HHR condition, progressive increases in porosity development with increasing pyrolysis temperature occurred, whereas a maximum porosity development appeared at 900°C. The total surface area (Stotal) and micropore surface area (Smicro) reached maximum values of 30.94 and 21.81m2/g at 900°C and decreased slightly at higher temperatures. The influence of heating rate on Stotal and Smicro was less significant than that of pyrolysis temperature. The pore surface fractal dimension and average pore diameter showed a good linear relationship.

Influence of a glass wool hot vapour filter on yields and properties of bio-oil derived from rapid pyrolysis of paddy residues

This article reports experimental results of rapid or fast pyrolysis of rice straw (RS) and rice husk (RH) in a fluidised-bed reactor unit incorporated with a hot vapour filter. The objective of this research was to investigate the effects of pyrolysis temperatures and the use of glass wool hot vapour filtration on pyrolysis products. The results showed that the optimum pyrolysis temperatures for RS and RH were 405 and 452°C, which gave maximum bio-oil yields of 54.1 and 57.1wt.% on dry biomass basis, respectively. The use of the hot filter led to a reduction of 4–7wt.% bio-oil yield. Nevertheless, the glass wool hot filtered bio-oils appeared to have better quality in terms of initial viscosity, solids content and ash content than the non-filtered ones.

Pyrolytic characteristics of rice straw and its constituents catalyzed by internal alkali and alkali earth metals

Pyrolysis of raw rice straw (RS), water-washed rice straw (WRS) and acid-washed rice straw (ARS) was conducted on a fixed bed reactor. A standard detergent method was used to determine the fiber constituents including neutral detergent solute (NDS), hemicellulose, cellulose and lignin in RS, WRS, ARS and their chars. Results showed that water washing removed most alkali metals (K and Na) from RS, and acid washing removed almost all alkali and alkali earth metals (K, Na, Ca and Mg); meanwhile, either washing eluted a portion of NDS but nearly unaffected hemicellulose, cellulose and lignin in RS. Attempts were made to assess the intermingled influences of the internal alkali and alkali earth metals (AAEMs) and the varied organic matter on the pyrolysis behaviors. It was revealed that the AAEMs inherent in RS had multiple impacts on the product distribution, the decomposition characteristics of fiber constituents, and the compositions of all gaseous, liquid, and char products.