Gumpon Prateepchaikul

HEAT PUMP DRYER PART 2: RESULTS OF THE SIMULATION

Heat pump dryer characteristics of four configurations, two open and two closed systems, are presented. The results are based on the simulation models developed in Part 1. Emphasis is given to the effects of ambient conditions, recirculating air ratio and evaporator bypass air ratio on the system performance. The criteria for evaluating the system performance are the specific moisture extraction rate (SMER), the moisture extraction rate (MER) and the coefficient of performance (COP). It was found that the ambient conditions and dryer efficiency play an important role in the system behaviour. Optimum performance achieved for one ambient condition cannot be assumed optimum for the others. The recirculating air ratio substantially affects the system performance while the evaporator bypass air ratio shows insignificant effect.

Emissions of particulate matter and associated polycyclic aromatic hydrocarbons from agricultural diesel engine fueled with degummed, deacidified mixed crude palm oil blends.

Mixed crude palm oil (MCPO), the mixture of palm fiber oil and palm kernel oil, has become of great interest as a renewable energy source. It can be easily extracted from whole dried palm fruits. In the present work, the degummed, deacidified MCPO was blended in petroleum diesel at portions of 30% and 40% by volume and then tested in agricultural diesel engines for long-term usage. The particulates from the exhaust of the engines were collected every 500 hr using a four-stage cascade air sampler. The 50% cut-off aerodynamic diameters for the first three stages were 10, 2.5 and 1 microm, while the last stage collected all particles smaller than 1 microm. Sixteen particle bounded polycyclic aromatic hydrocarbons (PAHs) were analyzed using a high performance liquid chromatography. The results indicated that the size distribution of particulate matter was in the accumulation mode and the pattern of total PAHs associated with fine-particles (< 1 microm) showed a dominance of larger molecular weight PAHs (4-6 aromatic rings), especially pyrene. The mass median diameter, PM and total PAH concentrations decreased when increasing the palm oil content, but increased when the running hours of the engine were increased. In addition, Commercial petroleum diesel (PB0) gave the highest value of carcinogenic potency equivalent (BaP(eq)) for all particle size ranges. As the palm oil was increased, the BaP(eq) decreased gradually. Therefore the degummed-deacidified MCPO blends are recommended for diesel substitute.

Development of an energy-efficient brick kiln

Brick making in developing countries, which relies on biomass fuel, is facing energy shortage. This paper reports a study aiming to develop an energy-efficient brick kiln. The drying, preheating, firing and cooling of bricks were studied by computer simulation of a fixed bed model and resulted in a new design of downdraft brick kiln. The new kiln has four chambers to serve the four processes separately but simultaneously. A heat recovery feature was incorporated in the kiln operation. A kiln was constructed for full-scale experimentation. The experiments showed that the specific energy consumption could be as low as 2·3 MJ kg−1 of brick, which was only half of that presently consumed in traditional open top updraft kilns. The energy efficiency of the new kiln was 62·6% on average.

Optimization of the comparative continuous process of ethyl and methyl ester productions using a static mixer reactor: a response surface methodology approach

ABSTRACT Static mixer was used as the continuous reactor in the biodiesel production. This study reports methyl ester and ethyl ester production from refined palm oil (RPO) using a 10 m long static mixer reactor. Alcohol content (vol.%), KOH (g.L−1), and static mixer length (m) were optimized to determine the ester purities with response surface methodology. As a result, 96.5 wt.% ester purity was substituted into the predicted models of FAME and FAEE. The appropriate conditions for methanolysis of 44.7 vol.% of methanol, 11.2 g.L−1 of KOH, and 4.8 m of static mixer length was obtained. The appropriate condition for ethanolysis were 45.3 vol.% of ethanol, 12.5 g.L−1 of KOH, and 5.1 m of static mixer length. From all statistical analysis data, KOH has a less significant effect when compared with other parameters, whereas alcohol content and static mixer length are first- and second-key, respectively. Alcohol consumption and reaction time for ethanolysis are more than for methanolysis. Regarding glycerol–ethyl ester separation, the glycerol phase of ethyl ester is more difficult than methyl ester.

Optimization of Base-Catalyzed Transesterification in Biodiesel Production from Refined Palm Oil via Circulation Process through Static Mixer Reactor

In this work, response surface methodology (RSM), with 5-level and 2-factor central composite design (CCD) was used to optimize the condition of base-catalyzed transesterification from refined palm oil. The two main parameters; methanol concentration and potassium hydroxide concentration, were varied to investigate the effect on the methyl ester purity. The result indicated that the KOH concentration was the most significant to produce methyl ester (the lowest p-values occurs in all response models). From excel solver, full quadratic model was obtained for predicting the response surface models. The suitable condition: 23.81 vol.% methanol and 11.80 wt.% KOH under temperature of 60°C and reaction time of 60 min, is the optimum condition.

Feasibility of Using High-Intensity Ultrasound Assisted Biodiesel Production from Mixed Crude Palm Oil in Two-Step Process

Biodiesel from a high free fatty acid (FFA) mixed crude palm oil (MCPO) can be produced to high fatty acid methyl ester (FAME) conversion by a two-step process. The first process is an acid-catalyzed esterification to reduce FFA in oil followed by a base-catalyzed transesterification process to produce biodiesel from esterified oil. In this study, the transesterification of esterified oil with methanol in the presence of potassium hydroxide (KOH) was performed in a 1,000 W ultrasonic homogenizer at a low frequency of 18 kHz. The use of high-intensity ultrasound to accelerate the reaction, the high surface power density of 1.62 W.mm-2 and the volumetric acoustic energy of 20 W.mL-1 were fixed. The objective of this study was to determine the various parameters (methanol concentration, KOH concentration, and initial temperature of oil) to produce the FAME conversion. The results showed that over 98 wt.% of FAME could be achieved with 5 g KOH/liter of oil, 15 vol.% of methanol, the total residence time of 20 seconds, and temperature of 30 oC. Moreover, the glycerides were rapidly converted to the FAME within reaction time of 10 seconds when the base-catalyst of 10 g KOH/liter of oil, and 20 vol.% of methanol were used. Consequently, the use of high-intensity ultrasonic irradiation can minimize the chemical cost, electricity cost, and reaction time.

Optimizing three-step production of methyl ester from palm fatty acid distillate: a response surface methodology approach

ABSTRACT Biodiesel production by a three-step batch process from palm fatty acid distillate (PFAD) that has high content of free fatty acids (FFA) was optimized with response surface methodology (RSM). Three key parameters for each step were investigated, namely methanol, catalyst and reaction time, to maximize the purity of ester. This gave the near optimal set-point at 29.46 wt.% methanol, 5.12 wt.% H2SO4 and 40 min reaction time for the first-step esterification. Similarly, 29.97 wt.% methanol, 5.94 wt.% H2SO4 and 40 min reaction time were near optimal for the second-step esterification, and 5.10 wt.% methanol, 0.50 g L−1 KOH, with 6 min reaction were near optimal for the third-step transesterification. Under these conditions the most FFA and partial glycerides in PFAD are converted to 99.822 wt.% ester. The obtained yields were: 106.53 wt.% of first-esterified oil, 108.86 wt.% of second-esterified oil, 112.34 wt.% of crude biodiesel and 93.13 wt.% of purified biodiesel. The amount of generated waste water and the total methanol consumption by this three-step process are lower than those of single-step esterification. Moreover, this three-step process provided methyl ester of higher purity than the single-step process did.

Continuous Transesterification for Ethyl Ester Production from Refined Palm Oil through Static Mixer

In this study, the commercial grade of ethanol was used to produce the biodiesel from refined palm oil (RPO) through the continuous static mixer system. The ethanol, an alternative alcohol to adopt in the ethyl ester production, can be used instead of methanol, and this alcohol is more eco-friendly than methanol. The 6-meter in length of SUS304 static mixer reactor is an essential part of mixing the RPO and solution of ethanol and potassium hydroxide to accelerate the base-catalyzed transesterification. The ethanol were varied at the volumetric flow rate of 30, 40, 50, 60 vol.%, KOH as base-catalyst was varied with the weight to volume of oil of 10,12,14 gKOH.L-1, to investigate the suitable condition which can converted the glycerides to the maximum purity of ethyl ester. The results showed that all varied conditions, the ethyl ester conversion was rapidly increased from 0 to over 95 wt.% when the flowing mixtures flowed through the 1 meter of static mixer. Furthermore, the highest purity of ethyl ester from RPO was succeeded when the condition: the 60 vol.% ethanol, the 14 gKOH.L-1 of catalyst, 5-meter of static mixer, and 75 oC temperature of RPO, was used in the continuous static mixer.

Effects of Acid Catalyst Types and Concentrations on Free Fatty Acid Reduction in Mixed Crude Palm Oil Using Continuous Static Mixer

Free fatty acid (FFA) in mixed crude palm oil (MCPO) must be reduced to less than 1 wt.% or 2 mgKOH.g-1 of acid value by the acid-catalyzed esterification process when the base-catalyzed transesterification was used to produce the biodiesel for the two-stage process. This study was to investigate the effects of acid catalyst types: sulfuric acid (H2SO4), phosphoric acid (H3PO4), and hydrochloric acid (HCL) at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 vol.% of acid catalyst concentration on the reduction of acid value in MCPO by the continuous static mixer. Results indicated that H2SO4 has the most significant variable affecting the acid value in MCPO. The acid catalyst concentration of 1.0 and 1.5 vol.% H2SO4 can reduce the acid value to less than 2 mgKOH.g-1 with 15 vol.% of methanol and 5-meter in the length of static mixer, while both H3PO4 and HCL could not reduce the acid value was reduced to less than 2 mgKOH.g-1. Moreover, the results clearly indicated that HCL has the lowest significance effect on the acid value reduction in MCPO by the esterification reaction.