Optimization of soluble sugar production from pineapple peel by microwave-assisted water pretreatment

The purpose of this study was to assess the potential of pineapple peel as a feedstock for fermentable sugar production. Soluble sugar production from pineapple peel was conducted in a process involving microwave-assisted water pretreatment without a catalyst in an apparatus set which prevented any loss of liquid or corrosion from vapor and reduced energy consumption. The pretreatment variables consisting of biomass loading (100-160 g/L), microwave power ( 90-900 watts) and irradiation time (5-20 minutes) were investigated by response surface methodology. The maximal total sugar yield in the liquid fraction after the pretreatment was 80.2% (80.2 g total sugars per 100 g dried peel) obtained using 100 g/L biomass loading at 900 watts for 9 minutes. Under these conditions, the glucose yield was 7.8% . This process offers an alternative approach to the cost-effective production of fermentable sugars from biomass-waste products, using less reagent and low energy in a self-reliant technology

Optimization of glucose production from corncob by microwave-assisted alkali pretreatment and acid hydrolysis

The production of reducing sugar is the most crucial process in the production of cellulosic ethanol and can be divided into two steps. First, pretreatment removes the unwanted constituents of lignocellulose to produce cellulose; then the cellulose is hydrolyzed to glucose (a reducing sugar) in the hydrolysis step. In this work, microwave heating was applied for both alkali pretreatment and sequential acid hydrolysis of corncob in which the conditions were optimized by response surface methodology. The optimal cellulose content in the pretreated corncob was 52.9 % w/w obtained with 1 M sodium hydroxide using a 1:12 weight ratio of corncob to solution at 900 W microwave power for 20 min, which was used to optimize the glucose yield in the following step. The highest yield of 14.8% glucose was achieved with 1.3% w/w sulfuric acid solution at 900 W for 16 min

Production of ethyl ester from crude palm oil by two-step reaction using continuous microwave system

The esterification of free fatty acids (FFA) in vegetable oils with alcohol using an acid catalyst is a promising methodto convert FFA into valuable ester and obtain a FFA-free oil that can be further transesterified using alkali bases. In thiswork, the direct esterification reaction of FFA in crude palm oil to ethyl ester by continuous microwave was studied and theeffects of the main variables involved in the process, amount of catalyst, reaction time and the molar ratio oil/ alcohol, wereanalyzed. The optimum condition for the continuous esterification process was carried out with a molar ratio of oil to ethanol1:6, using 1.25%wt of H2SO4/oil as a catalyst, microwave power of 78 W and a reaction time 90 min. This esterification processshows that the amount of FFA was reduced from 7.5%wt to values around 1.4 %wt. Similar results were obtained followingconventional heating at 70°C, but only after a reaction time of 240 min. The esterified crude palm oil is suitable to perform thetransesterification process. Transesterification of the esterified palm oil has been accomplished with a molar ratio of oil toethanol of 1:8.5, 2.5%wt of KOH as a catalyst, a microwave power of 78 W, and a reaction time of 7 min. In addition, theproblem of glycerin separation was solved by mixing 10%wt of pure glycerin into the ethyl ester to induce the glycerin fromthe reaction to separated. This two-step esterification and transesterification process provided a yield of 78%wt with anester content of 97.4%wt. The final ethyl ester product met with the specifications stipulated by ASTM D6751-02

Pretreatment of Palm Fruit by Using a Conveyor Belt Microwave Prototype

This paper presents a microwave drying prototype, which is a conveyor belt design for oil palm pretreatment. The prototype consists of four 800 W magnetrons launching electromagnetic energy to the rectangular waveguide cavity. Palm fruit was fed in the cavity by the conveyor belt and pretreated in the cavity. The cavity size was designed optimally to ensure that temperature distribution in the palm fruit is uniform. Another conveyor belt is applied to the cavity output to feed out the pretreated fruit. Two corrugated waveguide filters were installed at the conveyor belt ends to suppress the microwave leakage. Three hundred sixty palm fruit were pretreated to prove the prototype concept. From the experiment results, the prototype heated palm fruit to the temperature required for inhibiting lipase enzyme within 120 seconds. It is found that free fatty acids in the treated palm fruit was well below 2% even 1 week storage

Catalytic Cracking of Pyrolysis Oil Derived from Rubberwood to Produce Green Gasoline Components

An attempt was made to generate gasoline-range aromatics from pyrolysis oil derived from rubberwood. Catalytic cracking of the pyrolysis oil was conducted using an HZSM-5 catalyst in a dual reactor. The effects of reaction temperature, catalyst weight, and nitrogen flow rate were investigated to determine the yield of organic liquid product (OLP) and the percentage of gasoline aromatics in the OLP. The results showed that the maximum OLP yield was about 13.6 wt%, which was achieved at 511 C, a catalyst weight of 3.2 g, and an N2 flow rate of 3 mL/min. The maximum percentage of gasoline aromatics was about 27 wt%, which was obtained at 595 C, a catalyst weight of 5 g, and an N2 flow rate of 3 mL/min. Although the yield of gasoline aromatics was low, the expected components were detected in the OLP, including benzene, toluene, ethyl benzene, and xylenes (BTEX). These findings demonstrated that green gasoline aromatics can be produced from rubberwood pyrolysis oil via zeolite cracking

Design and test of a continuous reactor for palm oil transesterification

The continuous reactor for transesterification of refined palm oil with methanol was designed and tested. The reaction condition was focused at ambient pressure, temperature of 60ºC, molar ratio of alcohol to oil of 6:1, and NaOH of 1.0 %wt of oil. The designed reactor was in a form of a 6-stage mechanically stirred tank. Rushton turbines, with 4 standard baffles, and plates with a small opening were installed inside. The reactor has a simple form which could be conveniently constructed and operated. The reactor could produce methyl esters (ME) with purities ranging from 97.5-99.2 %wt within residence times of 6-12 minutes in which its production performance was equivalent to a plug flow reactor and the power consumption of a stirrer in the range of 0.2-0.6 kW/m3 was required. The reaction modeling based on a homogeneous concentration field with reaction kinetics could accurately predict the produced purities of ME. The production yields by weight of final product and of ME to the fed oil were 94.7 and 92.3%, respectively. The developed continuous reactor has good potential for producing ME to be used as biodiesel