Thiam Leng Chew

Catalytic processes towards the production of biofuels in a palm oil and oil palm biomass-based biorefinery.

In Malaysia, there has been interest in the utilization of palm oil and oil palm biomass for the production of environmental friendly biofuels. A biorefinery based on palm oil and oil palm biomass for the production of biofuels has been proposed. The catalytic technology plays major role in the different processing stages in a biorefinery for the production of liquid as well as gaseous biofuels. There are number of challenges to find suitable catalytic technology to be used in a typical biorefinery. These challenges include (1) economic barriers, (2) catalysts that facilitate highly selective conversion of substrate to desired products and (3) the issues related to design, operation and control of catalytic reactor. Therefore, the catalytic technology is one of the critical factors that control the successful operation of biorefinery. There are number of catalytic processes in a biorefinery which convert the renewable feedstocks into the desired biofuels. These include biodiesel production from palm oil, catalytic cracking of palm oil for the production of biofuels, the production of hydrogen as well as syngas from biomass gasification, Fischer-Tropsch synthesis (FTS) for the conversion of syngas into liquid fuels and upgrading of liquid/gas fuels obtained from liquefaction/pyrolysis of biomass. The selection of catalysts for these processes is essential in determining the product distribution (olefins, paraffins and oxygenated products). The integration of catalytic technology with compatible separation processes is a key challenge for biorefinery operation from the economic point of view. This paper focuses on different types of catalysts and their role in the catalytic processes for the production of biofuels in a typical palm oil and oil palm biomass-based biorefinery.

Conventional processes and membrane technology for carbon dioxide removal from natural gas: A review

Abstract Membrane technology is becoming more important for CO2 separation from natural gas in the new era due to its process simplicity, relative ease of operation and control, compact, and easy to scale up as compared with conventional processes. Conventional processes such as absorption and adsorption for CO2 separation from natural gas are generally more energy demanding and costly for both operation and maintenance. Polymeric membranes are the current commercial membranes used for CO2 separation from natural gas. However, polymeric membranes possess drawbacks such as low permeability and selectivity, plasticization at high temperatures, as well as insufficient thermal and chemical stability. The shortcomings of commercial polymeric membranes have motivated researchers to opt for other alternatives, especially inorganic membranes due to their higher thermal stability, good chemical resistance to solvents, high mechanical strength and long lifetime. Surface modifications can be utilized in inorganic membranes to further enhance the selectivity, permeability or catalytic activities of the membrane. This paper is to provide a comprehensive review on gas separation, comparing membrane technology with other conventional methods of recovering CO2 from natural gas, challenges of current commercial polymeric membranes and inorganic membranes for CO2 removal and membrane surface modification for improved selectivity.

Effect of catalyst additives on the production of biofuels from palm oil cracking in a transport riser reactor.

Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450 degrees C, with residence time of 20s and catalyst-to-oil ratio (CTO) of 5 gg(-1). The effect of HZSM-5 (different Si/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with cracking catalyst Rare earth-Y (REY). REY catalyst alone gave 75.8 wt% conversion with 34.5 wt% of gasoline fraction yield using CPO, whereas with UPO, the conversion was 70.9 wt% with gasoline fraction yield of 33.0 wt%. HZSM-5, beta zeolite, SBA-15 and AlSBA-15 as additives with REY increased the conversion and the yield of organic liquid product. The transport riser reactor can be used for the continuous production of biofuels from cracking of CPO and UPO over REY catalyst.

Synthesis and performance of microporous inorganic membranes for CO2 separation: a review

AbstractRemoval of CO2 by membrane technologies is one promising approach as compared to other CO2 capture technologies due to advantages such as simpler operation, higher reliability, lower capital and operating cost, higher energy efficiency, and a cleaner process. In the field of CO2 gas separation, inorganic membranes have been attracting a lot of attention. Three classes of microporous membrane family, i.e. microporous silica membranes, microporous carbon membranes and zeolite membranes, have been widely studied due to their potential in separating CO2 gas molecules, contributed by their distribution of selective micropores which are almost identical to the required molecular sizes for diffusing CO2 gas. This paper review various methods to fabricate the above three types of microporous membranes, at the same time, looking at other researchers employing these methods to fabricate microporous membranes for CO2 separation.

Ba-SAPO-34 Zeolite Membrane for CO2/N2 Separation: Process Optimization

In the present research, Ba-SAPO-34 membrane was formed using microwave heating and ion-exchange process. The membrane was subjected to CO2/N2 separation process considering 3 independent process variables as temperature, pressure difference across the membrane and CO2 % in the feed. Response surface methodology coupled with central composite design, available in Design Expert software was used to perform optimization for the 2 response CO2 permeance and CO2/N2 separation selectivity as a function of the 3 independent process variables. The optimum CO2 permeance and CO2/N2 separation selectivity was 17.54x10-7 mol/m2.s.Pa and 58.82 respectively at 30 oC, 145.10 kPa pressure difference and 5 % CO2 in the feed.

Microwave heating-synthesized zeolite membrane for CO2/CH4 separation

Abstract H-SAPO-34 membrane was synthesized using microwave heating at 200°C for 2 h. Ba-SAPO-34 membrane was obtained by ion-exchanging the H-SAPO-34 membrane with Ba2+ cation. The separation of CO2 from CO2/CH4 binary gas mixture was studied using design and analysis of experiments. The response surface methodology coupled with central composite design was used for modeling and analysis of the contribution of operating parameters (temperature, pressure difference across the membrane, CO2 concentration in the feed) to the responses (CO2 permeance and CO2/CH4 separation selectivity) during Ba-SAPO-34 membrane separation process. The process parameters were varied in the range of 30–180°C of temperature, 100–500 kPa of pressure difference and 5–50% of CO2 concentration in the feed. The optimum condition for the process parameters was determined by setting the criteria so as to maximize the CO2 permeance and CO2/CH4 separation selectivity. The optimum CO2 permeance of 38.46 × 10−7 mol/m2 s Pa and CO2/CH4 se...