Pyrolysis Of Cotton Stalk Research Articles

Influence of Microwave Power and Additive on Microwave-Assisted Pyrolysis of Cotton Stalk

Influence of Microwave Power and Additive on Microwave-Assisted Pyrolysis of Cotton Stalk

Microwave-assisted Pyrolysis of Cotton Stalk with Additives

The purpose of this study was to investigate the effects of microwave power and additives on the microwave-assisted pyrolysis of cotton stalk. Pyrolysis temperature profiles, product yields, and bio-oil components were analyzed. The results indicated that as the microwave power increased, so did the final temperature and heating rate. When microwave power increased from 800 to 1200 W, the yield of the solid residue decreased and gas yield increased, but the maximum bio-oil yield of 26.7% was achieved under a microwave power of 1000 W. All three of the additives (NaOH, Na2CO3, and H3PO4) increased the yields of solid residue and gas, while the yield of the bio-oil decreased. Gas chromatography-mass spectrometry (GC-MS) analysis indicated that the main components of bio-oil from microwave-assisted pyrolysis of pure sample were acetol, furfural, 2-methoxy-phenol, and 4-methyl-2-methoxy-phenol. Sodium hydroxide and sodium carbonate (NaOH and Na2CO3) greatly favor the formation of acetol. Phosphoric acid (H3PO4) remarkably promoted the formation of furfural and 4-methyl-2-methoxy-phenol, while H3PO4 inhibited the formation of acetol.

Bio-Oil Production from Fast Pyrolysis of Cotton Stalk in Fluidized Bed Reactor

Fast pyrolysis was used to convert waste biomass into bio-oil, which has a benefit of storage and transportation with the potential as a fossil oil substitute. Pakistani cotton stalk was pyrolyzed in a bench-scale bubbling fluidized bed reactor. The effect of reaction conditions such as temperature and feed size on the bio-oil, char and gas yields was investigated. The optimal pyrolysis temperature for the production of bio-oil was 490 °C which gave the maximum yield (36 wt%) of product at feed size of 1.0 mm. Bio-oil yield increased with the increase in temperature, while the yield of char decreased. The various properties of bio-oil attained under these pyrolysis conditions were defined. Chemical composition of bio-oil was determined using FTIR and GC–MS analysis, and major chemical compounds were phenols, carboxylic acids, ketones, aldehydes, furans and sugars.

Catalytic effect of MgCl2 on cotton stalk pyrolysis for chemical production at low temperature

Cotton stalk pyrolysis catalyzed by magnesium chloride was carried out in a fixed bed reactor in a temperature range of 493–553 K. The feedstock characteristics, product distribution, pyrolysis oil composition, and solid residue composition were analyzed. The presence of MgCl2 significantly changed the product distribution of the pyrolysis oil and oils with only two targeted chemicals successfully collected for the purpose of chemical production. The effects of catalyst loading and pyrolysis temperature on pyrolysis behaviour for the furfural and acetic acid production were studied systematically. The furfural and acetic acid concentration in pyrolysis oil increased in the presence of magnesium chloride in our investigated temperature range. The furfural and acetic acid contents in water‐free pyrolysis oil are about 54 % and 28 % when the pyrolysis temperature is 553 K. The results of solid product analysis showed that 85 % of hemicellulose was decomposed, while cellulose and lignin were relatively stable. This study makes it possible to produce chemicals from biomass material through a multi‐step pyrolysis process.

Prediction of concentration profiles and theoretical yields in lignocellulosic biomass pyrolysis

This work involved the prediction of the concentration profiles and theoretical yields in lignocellulosic biomass pyrolysis under real pyrolysis conditions. The competing reaction model was used and verified by the experimental data of the pyrolysis of oilseed rape straw and sesame stalk. The pyrolysis kinetic behaviors of the pyrolysis of peach branch, cotton stalk, and corn stalk under various conditions were simulated based on the model and their chemical compositions. The influences of the heating rate and final temperature on the theoretical yields of pyrolysis products and the pyrolysis time were obtained. Under the same conditions, the pyrolysis of peach branch gave the highest yield of volatile products, while the pyrolysis of cotton stalk gave the highest yield of char. The method presented in this work enables us to predict the concentration profiles and theoretical yields of different lignocellulosic materials under various pyrolysis conditions.

Applicability of Fraser–Suzuki function in kinetic analysis of DAEM processes and lignocellulosic biomass pyrolysis processes

In this work, a new method for fitting the conversion rate curves of the distributed activation energy model (DAEM) and lignocellulosic biomass pyrolysis process was introduced. The method was based on the curve fitting technique using the Fraser–Suzuki function. Various simulated DAEM processes were analyzed. The results showed that the conversion rate curve of one DAEM process could be described well by a Fraser–Suzuki function. According to the obtained parameters of the fitted Fraser–Suzuki functions, the influences of the DAEM parameters on the conversion rate curves of the corresponding DAEM processes can be quantitatively obtained. The experimental data of the pyrolysis of cotton stalk, oilseed rape straw, and rice straw were fitted by the Fraser–Suzuki mixture model which involves three individual Fraser–Suzuki functions. It has been found that the Fraser–Suzuki mixture model can reproduce accurately the conversion rate curves of the pyrolysis of three lignocellulosic biomass samples. The Fraser–Suzuki mixture model provides an approach to separate lignocellulosic biomass pyrolysis into three parallel reactions which link to the decomposition of hemicellulose, cellulose, and lignin, respectively.

Fractional Condensation of Multicomponent Vapors from Pyrolysis of Cotton Stalk

Bio-oil derived from the fast pyrolysis of biomass is a multicomponent mixture comprised of over 400 types of organics, which need to be separated for specific applications. Moisture contents and acids also have to be removed from the compounds for efficient energy consumption. In this study, unlike the conventional approaches of separating bio-oil after condensation, we developed a multicondenser system for separating bio-oil compounds in order to better utilize them in different applications. A biomass sample (cotton stalk) was pyrolyzed in a fluidized bed reactor operated at 400 and 600 °C. The pyrolysis vapors passed through four condensers arranged in sequence at 300 °C, 100 °C, 0 °C, and −20 °C, respectively. Each component on fractions was more efficiently separated based on their varied boiling points. Each fractional bio-oil (FBO) exhibits different chemical and physical properties. Over 90% of small molecular materials including acetic acid, ketones, aldehydes, and water, were gathered in the 0 ...

NOx and N2O precursors from biomass pyrolysis

Chlorine content in agricultural straw is high, and HCl formation during straw combustion is a challenging problem. The relationship between HCl and the formation of NOx and N2O is important and unclear. Effect of HCl in atmosphere on nitrogen transfer during wheat straw and cotton stalk pyrolysis was performed using a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer. Pyrolysis of polyvinyl chloride supplies HCl. The pathway of nitrogen transfer in the presence of HCl was studied. The results show that in the presence of HCl, the temperature corresponding to NH3 starting release during wheat straw pyrolysis increases, and those of HCN and HNCO reduce. HCl inhibits the conversion of straw–N into NH3, however, favors the transformation of straw nitrogen into HCN and HNCO.

Influence of NH3/CO2 Modification on the Characteristic of Biochar and the CO2 Capture

This paper was aimed to study the influence of modification of biochar on the performance of CO2 adsorption. Biochar, obtained from cotton stalk pyrolysis in a fixed bed reactor, was modified with ammonia and CO2. The physicochemical properties of biochars were characterized by the Fourier transform infrared spectroscopy and automatic adsorption equipment (Micromeritics, ASAP 2020, USA). CO2 adsorption of biochar was performed in thermogravimetric analyzer. The results showed that the surface area of char was increased significantly by CO2 modification, while N-contained compound on char surface was enriched obviously by NH3 modification. CO2 adsorption of biochar increased greatly with CO2 and NH3 modification. CO2 adsorption was mainly attributed to physical adsorption at 20 °C, and the adsorption quantity (maximum = 99 mg/g) was proportional to the micropore volume of the char. However, at 120 °C, molecular thermal motion increase, chemical adsorption start to play a dominated role, and the adsorption was directly proportional to the N content of this char.

Study on the gas evolution and char structural change during pyrolysis of cotton stalk

The gas release properties and char structural evolution during the pyrolysis of cotton stalk were investigated. The evolution characteristics of volatile products were examined by pyrolysis–Fourier transform infrared spectroscopy (FTIR)/thermal conductivity detection (TCD) analysis (Py–FTIR/TCD). The char chemical structure and physical characteristics were investigated by means of FTIR and N2 physisorption techniques. Evolution characteristics of the main volatile products were given. The evolution of CO2 was approximately 26°C earlier than that of CO. CH4 evolution covered over a wider temperature range of 300–600°C, with a maximum at 394°C. The amount of hydroxyl, aliphatic CH and olefinic CC bonds in the char decreased significantly above 250°C. The aromatization process started at ≈350°C and continued to higher temperatures, leaving the char enriched with condensed aromatic ring systems. The BET surface area increased continually with increasing temperature to reach a maximum value of 4.68m2/g at 500°C and decreased at higher temperatures. The micropore volume showed a similar behavior to the surface area, while the mesopore volume and total pore volume always increased.

Biomass-based pyrolytic polygeneration system on cotton stalk pyrolysis: Influence of temperature

To study the process of biomass-based pyrolytic polygeneration and its mechanism in depth, the pyrolysis of cotton stalk was investigated in a packed bed, with focus on the evolution of the chemical and physical structures of the solid, liquid and gaseous products. The evolution of product characteristics could be good explaining the process mechanism of biomass pyrolysis. A relationship between the pore distribution of solid products and the fused aromatic rings system revealed by Raman analysis might be exist and need to quantify in further study. Regarding the optimum conditions for obtaining high-quality pyrolytic products from the polygeneration system, the optimum temperature is 550–750°C, with a higher calorific value of the obtained charcoal (∼28MJ/kg) and a higher surface area (>200m2/g). Meanwhile, the calorific value of the gas reaches 8–9MJ/m3 and the liquid oil would be used as a platform product in biorefinery.

06/01244 Fixed-bed pyrolysis of cotton stalk for liquid and solid products: Pütün, A. et al. Fuel Processing Technology, 2005, 86, (11), 1207–1219

06/01244 Fixed-bed pyrolysis of cotton stalk for liquid and solid products: Pütün, A. et al. Fuel Processing Technology, 2005, 86, (11), 1207–1219

Catalytic effects of six inorganic compounds on pyrolysis of three kinds of biomass

Six inorganic compounds, i.e., Na 2CO 3, NaOH, NaCl, Na 2SiO 3, TiO 2 and HZSM-5, have been investigated with regard to their catalytic effects on pyrolysis of three biomass species, i.e., pine wood, cotton stalk and fir wood by thermal analysis experiments. The results show that Na 2CO 3, NaOH, Na 2SiO 3 and NaCl made devolatilization occur at lower temperature regions in the pyrolysis of the three kinds of biomass, whereas TiO 2 and HZSM-5 made that occur at higher temperature regions in the pyrolysis of cotton stalk and had no obvious effects on pyrolysis temperatures of pine wood and fir wood. The basic catalysts NaOH, Na 2CO 3 and Na 2SiO 3 decreased the maximum weight loss rates while NaCl and HZSM-5 increased them and TiO 2 had no obvious effects on them. The four sodium compounds made pyrolysis of the three kinds of biomass more exothermic, which might be due to more char formation, whereas TiO 2 and HZSM-5 had minor effects on reaction heat. The catalytic effects in all aspects were roughly correlated with one another and their relationship with the basicity and acidity of the catalysts were preliminarily described and analyzed.

Fixed-bed pyrolysis of cotton stalk for liquid and solid products

The pyrolysis of cotton stalk was studied for determining the main characteristics and quantities of liquid and solid products. Particular variables investigated were temperature (from 400 °C to 700 °C), particle sizes (from 0.25 mm to 1.8 mm) and nitrogen gas flow rate (from 50 and 400 cm 3/min). All experiments were performed at a heating rate of 7 °C/min. The results showed that particle size and nitrogen flow rate did not exert a significant influence, whereas temperature was very significant. The liquid products and the subfractions of pentane-soluble fraction were characterized by elemental analysis, FT-IR spectroscopy, 1H-NMR spectroscopy, and the pentane subfraction was analysed by gas chromatography. The characterization of char was performed in terms of its elemental composition, surface area and FT-IR spectroscopy. The H/C and O/C ratios of the chars decreased with the rise in the temperature. FT-IR showed that results the hydroxyl and carbonyl functionalities were lost at high temperatures. According to the experimental results the liquid products can be used as liquid fuels, whereas the solid products can be transformed to activated carbon for adsorption processes.