scholarly journals Microwave Hydrothermal Carbonization of Rice Straw: Optimization of Process Parameters and Upgrading of Chemical, Fuel, Structural and Thermal Properties

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 403 ◽  
Author(s):  
Sabzoi Nizamuddin ◽  
Sundus Qureshi ◽  
Humair Baloch ◽  
Muhammad Siddiqui ◽  
Pooja Takkalkar ◽  
...  
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Reaction Time ◽  
Rice Straw ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Hydrothermal Carbonization ◽  
Microwave Hydrothermal ◽  
Optimization Of Process Parameters ◽  
Water Ratio

The process parameters of microwave-induced hydrothermal carbonization (MIHTC) play an important role on the hydrothermal chars (hydrochar) yield. The effect of reaction temperature, reaction time, particle size and biomass to water ratio was optimized for hydrochar yield by modeling using the central composite design (CCD). Further, the rice straw and hydrochar at optimum conditions have been characterized for energy, chemical, structural and thermal properties. The optimum condition for hydrochar synthesis was found to be at a 180 °C reaction temperature, a 20 min reaction time, a 1:15 weight per volume (w/v) biomass to water ratio and a 3 mm particle size, yielding 57.9% of hydrochar. The higher heating value (HHV), carbon content and fixed carbon values increased from 12.3 MJ/kg, 37.19% and 14.37% for rice straw to 17.6 MJ/kg, 48.8% and 35.4% for hydrochar. The porosity, crystallinity and thermal stability of the hydrochar were improved remarkably compared to rice straw after MIHTC. Two characteristic peaks from XRD were observed at 2θ of 15° and 26°, whereas DTG peaks were observed at 50–150 °C and 300–350 °C for both the materials. Based on the results, it can be suggested that the hydrochar could be potentially used for adsorption, carbon sequestration, energy and agriculture applications.

scholarly journals Optimization of Process Parameters and Kinetics Analysis of Cd Removal in ZnSO4 Production

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1437
Author(s):  
Xiaoling Ren ◽  
Xinqian Shu ◽  
Haisheng Li ◽  
Jiushuai Deng ◽  
Peng Li ◽  
...  
Keyword(s):  
Reaction Time ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Zinc Powder ◽  
Diffusion Control ◽  
Process Conditions ◽  
Optimization Of Process Parameters ◽  
Removal Experiments ◽  
Main Effects ◽  
Cd Removal

In order to optimize the process parameters of Cd removal in the ZnSO4 production process and study the mechanism of Cd removal reaction, the response surface methodology was used to arrange Cd removal experiments and analyze the optimal production conditions, and the mechanism of Cd removal was studied using kinetics. The results show that the optimal process conditions for Cd removal are as follows: reaction temperature 55 °C, reaction time 13.43 min, and the zinc powder dosage should be 2.14 times that of Cd; the main effects of the three variables from large to small are zinc powder dosage, reaction temperature and reaction time; Cd removal is a second-order reaction, and the activation energy of the reaction is 29.6986 kJ/mol, so the reaction conforms to the diffusion control mechanism.

Taguchi Approach and ANOVA in Optimization of the Dissolution of Colemanite in CO2 and SO2- Water Systems

2020 ◽  
Vol 10 (2) ◽  
pp. 88-97
Author(s):  
Zafer Ekinci ◽  
Esref Kurdal ◽  
Meltem Kizilca Coruh
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Gas Flow ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Process Conditions ◽  
Liquid Ratio ◽  
Positive Effects ◽  
Controllable Factors

Background: Turkey is approximately 72% of the world’s boron sources. Colemanite, tincal, ulexite and pandermite are among the most significant in Turkey. Boron compounds and minerals are widely used in many industrial fields. Objective: The main purpose of this study was to investigate the control of impurities in the boric acid production process using colemanite by carrying out the reaction with a mixture of CO2 and SO2 - water, and determining the appropriate process conditions to develop a new process as an alternative to the use of sulfuric acid. Due to worrying environmental problems, intensive studies are being carried out globally to reduce the amount of CO2 and SO2 gases released to the atmosphere. Methods: The Taguchi method is an experimental design method that minimizes the product and process variability by selecting the most appropriate combination of the levels of controllable factors compared to uncontrollable factors. Results: It was evaluated the effects of parameters such as reaction temperature, solid-to liquid ratio, SO2/CO2 gas flow rate, particle size, stirring speed and reaction time. The optimum conditions determined to be reaction temperature of 45°C; a solid–liquid ratio of 0.083 g.mL−1; an SO2/CO2 ratio of 2/2 mL.s−1; a particle size of -0.354+0 .210 mm; a mixing speed of 750 rpm and a reaction time of 20 min. Conclusion: Under optimum operating conditions, 96.8% of colemanite was dissolved. It is thought that the industrial application of this study will have positive effects on the greenhouse effect by contributing to the reduction of CO2 and SO2 emissions that cause global warming.

Synthesis of Nd2Fe14B powders by spray-drying and reduction–diffusion processes

2001 ◽  
Vol 16 (4) ◽  
pp. 1083-1089 ◽  
Author(s):  
X. L. Dong ◽  
B. K. Kim ◽  
C. J. Choi ◽  
K. S. Park ◽  
Z. D. Zhang
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Spray Drying ◽  
Process Parameters ◽  
Diffusion Processes ◽  
Liquid Solution ◽  
Metal Salts ◽  
Mechanochemical Method ◽  
Precursor Powders ◽  
Spray Dried

The magnetic Nd–Fe–B powders were prepared by a mechanochemical method, including the processes of spray drying, debinding, milling, H2 reduction, Ca reduction, and washing. The liquid solution dissolved with various metal salts was first spray-dried to prepare the precursor powders having uniformly dispersed Nd, Fe, and B components. The precursor powders in turn were subjected to the subsequent processes. The particle size of the resultant Nd–Fe–B powders was about 1 μm. Effects of the process parameters on phases, morphologies, microstructures, compositions, and thermal properties of the powders were investigated.

Enhanced Photocatalytic Performance and Mechanism of Ag3PO4 Particles Synthesized via a Sonochemical Process

2018 ◽  
Vol 10 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Chengxiang Zheng ◽  
Hua Yang ◽  
Yang Yang ◽  
Haimin Zhang
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ph Value ◽  
Dye Degradation ◽  
Sonochemical Method ◽  
Simulated Sunlight ◽  
Spherical Nanoparticles ◽  
Direct Oxidation

A facile sonochemical method was used to synthesize Ag3PO4 particles and the effect of pH value, reaction temperature and reaction time on the products was investigated. It is found that the samples prepared at neutral (pH = 7) and alkaline (pH = 11) environments exhibit a similar particle morphology and size. The particles are shaped like spheres with a size distribution majorly focusing on a range of 200–450 nm, and the average particle size is about 300 nm. The sample prepared at acidic environment (pH = 3) is composed of polyhedral microparticles with size of 5–8 μm. At relatively low temperatures of 20–50 °C, the spherical nanoparticles do not undergo obvious morphology/size changes; however, when the temperature is increased up to 80 °C, the nanoparticles are aggregated to form large-sized polyhedral microparticles in the size range of 4–7 μm. Compared to the pH value and reaction temperature, the reaction time has a minor effect on the morphology of Ag3PO4 particles. RhB was chosen as the target pollutant to evaluate the photocatalytic activity of the as-prepared Ag3PO4 samples under simulated-sunlight irradiation. It is shown that the samples consisting of spherical nanoparticles exhibit an extremely high photocatalytic activity, and the degradation percentage of RhB after reaction for 50 min reaches over 90%. The samples of polyhedral microparticles have a relatively low photocatalytic activity, which is possibly due to their large particle size. Hydroxyl (.OH) radical was detected by spectrofluorimetry using terephthalic acid as a .OH scavenger and was not found to be produced over the simulated-sunlight-irradiated Ag3PO4 catalyst. The effect of ethanol, benzoquinone and ammonium oxalate on dye degradation was also investigated. Based on experimental results, the direct oxidation by h+ is suggested to the dominant mechanism toward the dye degradation.

Hybrid Approach for Optimizing Process Parameters in Biodiesel Production from Palm Oil

2020 ◽  
Vol 834 ◽  
pp. 16-23
Author(s):  
Pongchanun Luangpaiboon ◽  
Pasura Aungkulanon
Keyword(s):  
Reaction Time ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Palm Oil ◽  
Hybrid Approach ◽  
Maximum Yield ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Optimization Approach ◽  
Influential Parameters

Biodiesel was synthesized from direct transesterification of palm oil reacted with methanol in the presence of a suitable catalyst. There is a sequence of three consecutive reversible reactions for the transesterification process. These process parameters were optimized via the hybrid optimization approach of a conventional response surface method and artificial intelligence mechanisms from Sine Cosine and Thermal Exchange Optimization metaheuristics. The influential parameters and their combined interaction effects on the transesterification efficiency were established through a factorial designed experiments. In this study, the influential parameters being optimized to obtain the maximum yield of biodiesel were reaction temperature of 60–150°C, reaction time of 1–6 hours, methanol to oil molar ratio of 6:1–12:1 mol/mol and weight of catalyst of 1–10wt. %. On the first phase, the analysis of variance (ANOVA) revealed the reaction time as the most influential parameter on biodiesel production. Based on the experimental results from the hybrid algorithm via the SCO, it was concluded that the optimal biodiesel yield for the transesterification of palm oil were found to be 100°C for reaction temperature, 4 hours for reaction time, 10:1 wt/wt of ratio methanol to oil and 8% of weight of catalyst with 92.15% and 90.97% of biodiesel yield for expected and experimental values, respectively.

scholarly journals Investigation on the Synthesis Process of Bromoisobutyryl Esterified Starch and Its Sizing Properties: Viscosity Stability, Adhesion and Film Properties

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1936
Author(s):  
Wei Li ◽  
Jie Wu ◽  
Zhengqiao Zhang ◽  
Lanjuan Wu ◽  
Yuhao Lu
Keyword(s):  
Reaction Time ◽  
Polylactic Acid ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Graft Copolymers ◽  
Degree Of Crystallinity ◽  
Synthesis Process ◽  
Film Properties ◽  
Breaking Elongation ◽  
Viscosity Stability

To confirm the suitable synthesis process parameters of preparing bromoisobutyryl esterified starch (BBES), the influences of the synthesis process parameters—amount of 2-bromoisobutyryl bromide (BIBB), amount of catalyst (DMAP), reaction temperature and reaction time—upon the degree of substitution (DS) were investigated. Then, to produce a positive effect on the properties of graft copolymers of BBES prepared in the near future, a series of BBES samples were successfully prepared, and their sizing properties, such as apparent viscosity and viscosity stability, adhesion, and film properties, were examined. The BBES granules were characterized by Fourier transform infra-red spectroscopy and scanning electron microscopy. The adhesion was examined by determining the bonding forces of the sized polylactic acid (PLA) and polyester roving. The film properties were investigated in terms of tensile strength, breaking elongation, degree of crystallinity, and cross-section analysis. The results showed that a suitable synthesis process of BBES was: reaction time of 24 h, reaction temperature of 40 °C, and 0.23 in the molar ratio of 4-dimethylaminopyridine to 2-bromoisobutyryl bromide. The bromoisobutyryl esterification played the important roles in the properties of the starch, such as paste stabilities of above 85% for satisfying the requirement in the stability for sizing, improvement of the adhesion to polylactic acid and polyester fibers, and reduction of film brittleness. With rising DS, bonding forces of BBES to the fibers increased and then decreased. BBES (DS = 0.016) had the highest force and breaking elongation of the film. Considering the experimental results, BBES (DS = 0.016) showed potential in the PLA and polyester sizing, and will not lead to a negative influence on the properties of graft copolymers of BBES.

Study of the Impact of Rice Straw Particle Size on the Mechanical and Thermal Properties of Straw Lime Concretes

2022 ◽  
Author(s):  
Youssef El Moussi ◽  
Laurent Clerc ◽  
Jean-Charles Benezet
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Water Absorption ◽  
Rice Straw ◽  
Absorption Capacity ◽  
Mechanical And Thermal Properties ◽  
Water Absorption Capacity ◽  
The Impact

The use of bio-based concretes performed with lignocellulosic aggregates constitute an interesting solution for reducing the energy consumption, greenhouse gas emissions and CO2 generated by the building sector. Indeed, bio-based materials could be used as an alternative of traditional materials such as expended polystyrene and mineral resources (e.g. glass and rock wools) for insulation. Furthermore, these bio-based concretes are known for their interesting insulation properties, indeed they allow to enhance thermal properties of buildings and enables moisture management which lead to design efficient building materials. For this purpose, bio-based concrete using rice straw as aggregate are studied in this present work. The impact of the characteristics of rice straw particle (particle size distribution, bulk density, and water absorption capacity, etc.) on both the mechanical and thermal properties of the bio-based concrete are investigated. Five formulations of rice straw concrete are examined, compared and then classified in terms of insulation properties and mechanical properties. The assessments are based on the measurement of density and thermal conductivity. The variation of compressive strength in function of the characteristics (mean particle length) of rice straw particle are assessed and discussed. The investigation covers also the porosity and density. Tests are also carried out on agricultural by-products with a view to highlight their chemical, physical and structural proprieties. The results show that the use of large particles with low water absorption capacity induce lighter concretes with the density between 339 and 505 kg/m3 and lead to a high compressive strength with a high mechanical deformability. Furthermore, it appears that an increase in the average length of rice straw particle lead to decrease of thermal conductivity of bio-based concretes. It varies from 0.062 to 0.085 W/(m.K).

Preparating Arsenic Trioxide with Sulfuric Acid Wet Oxidation

2013 ◽  
Vol 662 ◽  
pp. 437-440
Author(s):  
Lin Zhuan Ma ◽  
Jun Ming Guo ◽  
Qiong Fang Cui ◽  
Man Hong Liu ◽  
Ying Jie Zhang
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Reaction Time ◽  
Arsenic Trioxide ◽  
Reaction Temperature ◽  
Extraction Yield ◽  
Wet Oxidation ◽  
Optimal Conditions ◽  
Concentrated Sulfuric Acid

The technology of the acidification is adopted to prepare arsenic trioxide (As2O3). With a concentration of 98% of concentrated sulfuric acid and Orpiment made into a certain ratio of the slurry suspension. Arsenic trioxide’s content is 99.94%, extraction yield can reach to 98.92%. The optimal conditions is reaction temperature at 120°Cand the reaction time in 2.5 h; the slurry ratio is less than 1/6 and particle size is less than 0.080 mm.

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