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Chaiyot Tangsathitkulchai,Yuvarat Ngernyen,Malee Tangsathitkulchai 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.5
The incorporation of oxygen functional groups onto the surface of eucalyptus activated carbon and its surface chemistry were investigated as a function of oxidation conditions, carbon porous properties and carbon preparation method. Under all treatment conditions of increasing time, temperature and oxidant concentration, liquid oxidation with HNO3, H2O2 and (NH4)2S2O8 and air oxidation led to the increase of acidic group concentration, with carboxylic acid showing the largest percentage increase and air oxidation at the maximum allowable temperature of 350℃ produced the maximum content of both carboxylic acid and total acidic group. Nitric acid oxidation of chemically activated carbon produced higher total acidic content but a lower amount of carboxylic acid compared to the oxidized carbon from physical activation. The increased contents of acidic groups on oxidized carbons greatly enhanced the adsorption capacity of water vapor and heavy metal ions.
Chaiyot Tangsathitkulchai,Supunnee Junpirom,Malee Tangsathitkulchai,Yuvarat Ngernyen 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.4
This work presents the behavior of water adsorption in the activated carbons with different porous structure derived by varying the level of char burn-off. Water adsorption isotherms of activated carbons prepared from longan seed at three different burn-offs (19, 26 and 60%) were measured gravimetrically. These obtained carbons were different in terms of their pore size distribution and also the surface functional group properties by showing an increasing of total pore volume and the concentration of surface functional groups with increasing in the burn-off level. The water adsorption isotherms showed that the behavior and amount of water uptake could be divided into three consecutive ranges of relative pressure, 0.0-0.3, 0.3-0.7 and 0.7-0.94, corresponding to adsorption in ultramicropores, supermicropores, and mesopores, respectively. The isotherm data were simulated by a cluster model proposed by Do and Do. The correlation was found to be satisfactory over the entire range of relative pressure only with the lowest burn-off carbon which contained mainly micropores. For higher burn-off carbons, which showed increasing proportions of mesopores, the model needed to be modified by increasing the cluster size of the adsorbed water molecules from 5 to 20 for adsorption at relative pressures greater than about 0.7.
Chaiyot Tangsathitkulchai,Piyarat Weerachanchai,Malee Tangsathitkulchai 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12
Three bio-oil samples, namely, raw bio-oil from pyrolysis of cassava pulp residue (CPR), separated oil phase and aqueous phase of bio-oil from pyrolysis of palm shell (PS), were used as suspending media for preparing slurries of bio-oil and the co-product char. Rheologies of all tested slurries exhibited pseudoplasticity with yield stress and the degree of this non-Newtonian behavior depended on such parameters as slurry type, solid concentration, particle size and slurry temperature. Overall, char/bio-oil slurries gave better fuel properties including higher pH and reasonably high calorific value (18-32 MJ/kg) as compared to their bio-oil properties. Combustion of char/bio-oil slurries occurred in the temperature range similar to their solid char combustion and without ignition delay.
Thermogravimetric analysis of longan seed biomass with a two-parallel reactions model
Supunnee Junpirom,Malee Tangsathitkulchai,Chaiyot Tangsathitkulchai 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.3
The kinetic analysis of pyrolysis process of longan seed was performed in a thermogravimetric analyzer. All experimental runs were carried out by using an initial sample mass of 15 mg and final temperature of 650 oC under the inert atmosphere of nitrogen. Particle sizes in the range from 0.05-2.1 mm and the heating rates from 5-100 oC/min were employed to investigate their effects on the thermogram and the kinetic parameters. The TG curves generally showed sigmoid shape and displayed one major peak in DTG curve. The main devolatilization of longan seed occurred over the temperature range of 210-330 oC. It was found that heat transfer resistance in a particle could be reduced either by decreasing the size of particle or increasing the heating rate. The thermal decomposition of longan seed could be well described by the two-parallel reactions kinetic model. This analysis of reaction kinetic gave the values of activation energy for the decomposition of the two fractions in the model corresponding closely to those of hemicellulose and lignin.
Effect of reaction conditions on the catalytic esterification of bio-oil
Piyarat Weerachanchai,Chaiyot Tangsathitkulchai,Malee Tangsathitkulchai 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.2
Studies of bio-oil upgrading via esterification of palm shell bio-oil and alcohols employing acid catalysts were carried out in this work. The effects of esterification conditions on reaction conversion and product quality were investigated. Results indicated that esterification reaction using solid acid catalyst of Amberlyst15 enabled the conversion of organic acids in the bio-oil to esters and could also reduce certain amount of active aldehydes. The utilization of H2SO4 liquid catalyst was found to give higher conversion at the same reaction condition. Furthermore, higher reaction conversion to esters was achievable under conditions of higher temperature, longer reaction time, higher amounts of catalyst and alcohol and the use of shorter hydrocarbon chain of alcohol. Bio-oils, after being subjected to esterification,gave moderate heating value of 23-25 MJ/kg and improved fuel properties of decreased density, viscosity, carbon residue content, ash content, pour point and acidity.
Characterization of products from slow pyrolysis of palm kernel cake and cassava pulp residue
Piyarat Weerachanchai,Chaiyot Tangsathitkulchai,Malee Tangsathitkulchai 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.12
Slow pyrolysis studies of palm kernel cake (PKC) and cassava pulp residue (CPR) were conducted in a fixed-bed reactor. Maximum liquid yield (54.3 wt%) was obtained from PKC pyrolysis at 700 oC, heating rate of 20 oC/min, N2 gas flow rate of 200 cm3/min and particle size of 2.03 mm. Fuel properties of bi-oils were in following ranges:density, 1.01-1.16 g/cm3; pH, 2.8-5.6; flash point, 74-110 oC and heating value, 15MJ/kg for CPR oil and 40 MJ/kg for PKC oil. PKC oil gave main contents of n-C8-C18 carboxylic acids, phenols, and esters, whereas CPR oil gave the highest amount of methanol soluble fraction consisting of polar and non-volatile compounds. On gas compositions,CPR pyrolysis gave the highest yield of syngas produced, while PKC pyrolysis offered the highest content of CO2. Pyrolysis chars possessed high calorific values in range from 29-35MJ/kg with PKC char showing a characteristic of reasonably high porosity material.