Mohd Fauzi Abdullah

Liquefaction studies of low-rank Malaysian coal using high-pressure high-temperature batch-wise reactor

ABSTRACT Direct liquefaction of low-rank Malaysian coal from the Mukah Balingian (MB) area was successfully carried out in a 1000 ml high-temperature (360–450°C) high-pressure (4–13 MPa) batch-wise reactor system using tetralin as hydrogen donor solvent. The results indicated that the percent coal conversion obtained were in the range of 31–90%. At optimum conditions of 450°C and 4 MPa, the oil + gas, asphaltene and preasphaltene of the coal extract were 80%, 7%, and 2%, respectively. It was observed that heat plays an important role in comparison to pressure in contributing to high coal conversion, oil yield, and organic properties of the residues. The high coal conversion and oil yield correlate well with the high content of reactive macerals, i.e., vitrinite and exinite, in the coal. Other parameters that were also investigated include the effect of reaction time (0–120 min) and coal-to-solvent ratio. A high yield of asphaltene and preasphaltene was obtained at the longest reaction time (i.e., 120 min). Coal conversion and oil yield increase with increasing in coal-to-solvent ratio, with the optimal ratio being 1:5.

Co-liquefaction of low rank Malaysian coal and Palm Kernel Shell — The effect of temperature

The co-liquefaction of Mukah Balingian (MB) Malaysian coal with the Palm Kernel Shell (PKS) was studied to investigate the synergistic effect by comparing the conversion and product yields. Co-liquefaction results thus far indicate there exists an obvious synergestic effect between MB and PKS, which is depends on liquefaction temperature. Thus far, the results showed that the conversion and oil + gas yields were comparatively much higher than the liquefaction of the MB coal alone. The largest synergistic effect is obtained at low temperature of 400 °C and then decreases as temperature increase. The liquefaction conversion of 88.6 % and oil+gas of 77.6 % of the co-liquefaction at this optimal temperature are higher than that of corresponding values from the invidual liquefaction of MB coal.

Thermogravimetric analysis of Silantek coal, Palm Kernel Shell, Palm Kernel Shell char and their blends during combustion

Preliminary thermogravimetric studies of Silantek coal (SL), Palm Kernel Shell (PKS), PKS char and their blends have been performed in a Thermogravimetry Analyser(TGA). PKS char were produced using microwave irradiation carbonization system at power of 300 Watt, with nitrogen flow rate of 150 mL/min for 30 minutes. Combustion tests of raw and blends samples were carried out in purified air atmosphere conditions at heating rates of 20 °C/min. The SL/ PKS and SL/ PKS char blends were prepared in the weight ratios of 80:20, 60:40, 50:50, 40:60 and 20:80. Derivative thermogravimetric (DTG) results which represent the decomposition of volatile matters and char showed that raw PKS has higher reactivity than SL during combustion process. The thermal profiles of the SL: PKS blends correlated with the percentage of PKS added in the blends, representing lack of synergic effect between both samples. SL and PKS char blends results in single evolution peak, indicated possibility to be used as alternative fuel for combustion. These findings may be useful for the power generation industry in the development of future co-firing plants using coal/ biomass; however, significant development work is required before large-scale implementation can be done.

Characteristics and Thermal Behaviour of Low Rank Malaysian Coals towards Liquefaction Performance via Thermogravimetric Analysis

In this study, thermal behaviour of two low-rank Malaysian coals namely Mukah Balingian (MB) and Batu Arang (BA) were obtained under pyrolysis conditions via Thermogravimetric analysis (TGA) at a heating rate of 20°C min-1. The thermal characteristics of the coals were investigated prior to direct liquefaction in order to determine the liquefaction performance, i.e. coal conversion and oil yield. The differential weight loss (DTG) results for both coals showed that there are three main stages evolved which consists of moisture, volatile matter and heavier hydrocarbons that correspond to temperature range of 150, 200-500 and 550-800°C, respectively. Apparently, the DTG curves of BA coal reveals a similar pattern of thermal evolution profile in comparison to that of the MB coal. However, the calculated mean reactivity of BA coal is higher than that of MB, which implied that BA would probably enhance coal conversion and oil yield in comparison to MB coal. Interestingly, results showed that under the same liquefaction conditions (i.e. at 4MPa pressure and 420°C), conversion and oil yield of both coals were well correlated with their reactivity and petrofactor value obtained.