Papers by Ridzuan Zakaria
Applied Catalysis A: General, 2004
Composite materials composed of MCM-41/Beta were synthesized using two methods: (1) seeding metho... more Composite materials composed of MCM-41/Beta were synthesized using two methods: (1) seeding method, and (2) two-step crystallization process. Powder XRD showed the existence of well-structured microphase zeolite Beta and mesophase MCM-41 in the composite materials. The performance of the composite material as a catalyst was investigated in the cracking of waste used palm oil for the production of liquid hydrocarbons and its activity was compared with the catalytic activity of a physical mixture of zeolite Beta and MCM-41. The composite material synthesized via seeding method gave a better performance in terms of conversion and yield of liquid fuel gasoline fraction compared to composite material obtained from two-step crystallization process and physical mixing. The composite material was found to be more selective for liquid fuel gasoline fraction enriched with more olefins compared to zeolite Beta or MCM-41 catalyst alone.
Tremendous increase in generation of Municipal Solid Waste (MSW) has become a major concern for t... more Tremendous increase in generation of Municipal Solid Waste (MSW) has become a major concern for the Ma-laysian government as the country experiencing rapid development. It was estimated about 16000 tones/day MSW is produced at national level and in Kuala Lumpur alone about 2500 tones/day. Annually, it was predicted to rise about 2%. Incineration, being one of the Integrated Waste Management Solution (IWMS) was found to be a best option to overcome the waste management problem; it is proven by the number of incinerators available in devel-oped country such as Japan, which exceeding 1000 units. This is clearly confirmed, that incineration has become one of the best options because it gives volume and weighs reduction of the MSW by 83 % and 91 % respectively. Currently, an incineration pilot plant called Thermal Oxidation Plant (TOP) has been installed in Malaysia Institute for Nuclear Technology Research (MINT) and it is experiencing delay in ram up time in primary chamber which has r...
Solid Waste Engineering and Management
pertanika journal of science and technology, 2009
The adsorption of phenol, from aqueous solutions on activated carbon from waste tyres, was studie... more The adsorption of phenol, from aqueous solutions on activated carbon from waste tyres, was studied in a batch system at different initial concentrations (100-500mg/L) at 30°C for 48 hours. The activated carbon was prepared using the two-step physiochemical activation, with potassium hydroxide (KOH) at ratio KOH/char = 5. The carbonization process was done at 800°C for 1 hour with nitrogen flow rate 150ml/min, followed by the activation with the carbon dioxide flow rate 150ml/min at 800°C for 2 hours. The adsorption isotherms were determined by shaking 0.1g of activated carbon with 100ml phenol solutions. The initial and final concentrations of phenol in aqueous solution were analyzed using the UV-Visible Spectrophotometer (Shimadzu, UV-1601) at a wavelength of 270nm. Experimental isotherm data were analyzed using the Langmuir and Freundlich isotherm models. The equilibrium data for phenol adsorption could fit both isotherm models well with the R2 value of 0.9774 and 0.9895, respecti...
Journal of The Institute of Energy, 1998
The growing scarcity of dumping sites for municipal solid waste, and the increasing environmental... more The growing scarcity of dumping sites for municipal solid waste, and the increasing environmental problems associated with landfill waste, have led to more stringent regulations and high costs of waste disposal. In the UK, landfill tax is designed to encourage energy-efficient waste-managements strategies aimed at reducing the amount of landfill waste through incineration, while maximising the recovery of waste energy. However, at present, reliable data and fundamentally based design procedures are not available to assist the design and manufacture of incinerators. The development of computational fluid dynamics (CFD) provides a means of modelling the gas-phase region in conventional incinerators, but the open literature contains no model that can accurately predict the conditions within a solid bed. Consequently, operation or control of municipal waste incinerators is still based on empirical relationships. Further research into secondary combustion, concerning the destiny of conta...
As a result of growing scarcity of landfill sites and environmental problems associated with land... more As a result of growing scarcity of landfill sites and environmental problems associated with landfill, incineration is now accepted as the most environmentally friendly means of disposing of municipal solid waste (MSW) safely. However, like all combustion processes, incineration cannot escape from producing harmful pollutants such as dioxins, furans, SO x and NO x . In municipal solid waste incinerators, NO x emission from the burning waste bed originates mainly from nitrogen in the waste. This is due to the relatively lower flame temperatures in incinerators than in other combustion systems. The currently popular method to reduce NO x is based on selective catalytic or non-catalytic reaction with ammonia or urea. An alternative strategy without introducing ammonia as an extra pollutant is to chemically reduce the NO x in conjunction with combustion. Detailed experiments with simulated waste were successfully carried out in a laboratory combustion rig in order to provide an understa...
Materials Today: Proceedings, 2021
Organomontmorillonites were synthesized by grafting cationic surfactants i.e quaternary ammonium ... more Organomontmorillonites were synthesized by grafting cationic surfactants i.e quaternary ammonium compounds into the interlayer space and were characterized using XRD, FTIR and N 2 adsorption/ desorption analysis. The organomontmorillonites were applied as catalyst for the esterification of glycerol ( GL) with lauric acid (LA). The catalyst which had symmetrical onium salts (tetrabuthylammoniumbromide, TBAB) gave higher activity than that of unsymmetrical onium salts (cetyltrimethylammoniumbromide, CTAB). Over the TBAB-montmorillonite catalyst, glycerol monolaurate was obtained with a selectivity of about 80%, a lauric acid conversion of about 71% and a glycerol monolaurate yield of about 57%.
Thermal and catalytic cracking over synthesized nickel-molybdenum supported on aluminum borate (N... more Thermal and catalytic cracking over synthesized nickel-molybdenum supported on aluminum borate (NiMo/AB) catalysts were studied. A series of aluminum borate supports with various aluminum borate (AlB) weight ratios were prepared by precipitation method. NiMo/AB catalysts were prepared by impregnation of nickel nitrate hexahydrate (Ni(N03)z.6H20) and ammonium heptamolybdate tetrahydrate ((NH4)~o7024.4H20) solution. These samples have been characterized with respect to surface areas, average pore diameters, pore size distribution, and acidity strengths. Thermal and catalytic cracking of atmospheric petroleum residue oil were carried out in a high pressure batch reactor at 340"C, 3 h reaction time and 0.5 g catalyst loading. The results revealed that catalytic cracking gave better product conversion and yield compared to thermal reaction. The conversion was 51.43 wt% from thermal reaction compared to 60-65 wt% from catalytic cracking. The yield of gasoline was 6.25 wt% and 11.5-13...
Landfill, a common technique used for solid waste disposal in Malaysia, currently cannot effectiv... more Landfill, a common technique used for solid waste disposal in Malaysia, currently cannot effectively manage it due to the increasing volume of municipal solid waste (MSW) generated daily in this country. Alternatively, incineration of MSW should be implemented in view of the advantages in waste volume reduction, waste stabilization, waste to energy conversion and sanitization of waste. A case study for investigating the combustion characteristics of MSW from Penang State has been carried out in Pulau Burung Sanitary Landfill. The representative samples of MSW taken from this area were used in proximate and ultimate analysis as well as in higher heating value (HHV) determination. The findings of the proximate analysis showed that the investigated MSW comprised 44.66% of moisture content, 44.55% of volatile matter, 8.56% of ash content and 2.23% of fixed carbon content. The ultimate analysis of the MSW shows that the main content were 43.97% for carbon, 39.40% for oxygen and other com...
Landfill, a common technique used for solid waste disposal in Malaysia, currently cannot effectiv... more Landfill, a common technique used for solid waste disposal in Malaysia, currently cannot effectively manage it due to the increasing volume of municipal solid waste (MSW) generated daily in this country. Alternatively, incineration of MSW should be implemented in view of the advantages in waste volume reduction, waste stabilization, waste to energy conversion and sanitization of waste. A case study for investigating the combustion characteristics of MSW from Penang State has been carried out in Pulau Burung Sanitary Landfill. The representative samples of MSW taken from this area were used in proximate and ultimate analysis as well as in higher heating value (HHV) determination. The findings of the proximate analysis showed that the investigated MSW comprised 44.66% of moisture content, 44.55% of volatile matter, 8.56% of ash content and 2.23% of fixed carbon content. The ultimate analysis of the MSW shows that the main content were 43.97% for carbon, 39.40% for oxygen and other compositions for hydrogen, nitrogen, sulfur and ash were recorded as 6.83%, 0.91%, 0.34% and 8.55%, respectively. The HHV of MSW obtained was 9.8532 MJ/kg, which is a typical value for developing countries. To further investigate the main sources that contributing toward HHV of MSW, the HHV obtained for the specific MSW was plotted against its physical composition (moisture, ash, volatile matter and fixed carbon) and chemical composition (C, H, O, N and S). There was a significant trend observed that volatile matter and carbon content showed a positive contribution to HHV of MSW whereas, moisture and oxygen content contributed negatively to the HHV.
Materials Today: Proceedings
International Journal of Biomedical Engineering and Technology, 2016
Municipal solid waste (MSW) management always becomes a big issue in most cities because of massi... more Municipal solid waste (MSW) management always becomes a big issue in most cities because of massive urbanization and rapid economic growth. At present, landfills are chosen as the most conventional method for the MSW disposal in Malaysia but disposal of solid waste through this method is not a sustainable option since the availability of the landfill sites is limited and increase in landfill charges. In order to overcome this problem, utilization of the solid waste before final disposal must be carried out. Thermal treatment of waste with the heat recovery that is commonly known as waste to energy (WTE) is considered to be one of the preferred options to utilize MSW. Currently, the thermal treatment technologies that are being used worldwide for energy recovery of MSW are incineration/combustion, gasification and pyrolysis. In this paper, gasification of MSW is discussed. Current and previous successful researches on WTE by gasification process are selected and discussed in terms of energy efficiency, environmental impact and its benefit towards society.
USY zeolite supported NiMo, CoMo, NiW and CoW catalysts was used to investigate the conversion of... more USY zeolite supported NiMo, CoMo, NiW and CoW catalysts was used to investigate the conversion of petroleum gas oil to distilled fuels. The catalysts were prepared using the incipient wetness method. The hydrocracking reaction was carried out in a high-pressure shaking reactor at reaction temperature of 450 oC, contact time of 90 minutes and catalyst to gas oil ratio of
Tremendous increase in generation of Municipal Solid Waste (MSW) has become a major concern for t... more Tremendous increase in generation of Municipal Solid Waste (MSW) has become a major concern for the Ma- laysian government as the country experiencing rapid development. It was estimated about 16000 tones/day MSW is produced at national level and in Kuala Lumpur alone about 2500 tones/day. Annually, it was predicted to rise about 2%. Incineration, being one of the Integrated Waste
Waste Management, 2002
The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathemati... more The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathematical modelling and understanding of the incineration process. In this paper, governing equations for mass, momentum and heat transfer for both solid and gaseous phases in a moving bed in a solid-waste incineration furnace are described and relevant sub-models are presented. The burning rates of volatile hydrocarbons in the moving bed of solids are limited not only by the reaction kinetics but also the mixing of the volatile fuels with the under-fire air. The mixing rate is averaged across a computation cell and correlated to a number of parameters including local void fraction of the bed, gas velocity and a length scale comparable to the particle size in the bed. A correlation equation is also included to calculate the mixing in the freeboard area immediately next to the bed surface. A small-scale fixed bed waste incinerator was built and test runs were made in which total mass loss from the bed, temperature and gas composition at different locations along the bed height were measured. A 2-D bed-modelling program (FLIC) was developed which incorporates the various sub-process models and solves the governing equations for both gases and solids. Thermal and chemical processes are mainly confined within a layer about 5-9 times in thickness of the averaged particle size in the burning bed. For a large part of the burning process, the total mass loss rate was constant until the solid waste was totally dried out and a period of highly rising CO emission followed. The maximum bed temperature was around 1200 K. The whole burning process ended within 60 min. Big fluctuations in species concentration were observed due to channelling and subsequent 'catastrophic' changes in the local bed conditions. Reasonably good agreement between modelling and measurements has been achieved. Yet the modelling work is complicated by the channelling phenomenon in the bed. Numerical simulations without consideration of the channelling effect produced very good agreement with experiments concerning the total mass loss, but significant discrepancy exists for temperature and gas composition profiles. Transient phenomena such as the breaking of waste particles and the "catastrophic" creation of new burning channels occurring during waste incineration is a vital area requiring further investigation at the fundamental level. The underlying theory of bed behaviour must be extended to include these transient events.
Process Safety and Environmental Protection, 2000
he safe disposal of municipal solid waste has now become an urgent environmental problem. The tra... more he safe disposal of municipal solid waste has now become an urgent environmental problem. The traditional method of land®lling waste has created so many environmental problems that countries including Denmark, Holland and Germany have imposed severe restrictions on land®lling burnable waste. With up to 1 tonne of municipal waste being generated by every individual annually in the UK, incineration is now at the forefront of combustion research, as developed countries recognize the environmentally friendly advantages of this technology. An ef®cient incinerator is not only assessed by the amount of heat recovery but also by the levels of emissions and quality of the ash it produces. Incinerator designs must therefore be fully optimized so that they can control emissions by reducing the production of harmful pollutants such as dioxins, furans, NO x and SO x. Hence, incinerator bed combustion is a vital area that urgently needs further investigation. At SUWIC, the present work concentrates on the development of a comprehensive and reliable model for the incinerator bed combustion process. The results from the incinerator burning bed model can then provide the much needed boundary conditions for Computational Fluid Dynamics (CFD) modelling of the gas phase reacting turbulent¯ow in the freeboard region of an incinerator. In addition to the development of the computational model, the work involves several parallel activities, including experimental investigations into waste combustion, solid mixing and prevention of slag formation and instrumentation development.
Journal of Porous Media, 2010
ABSTRACT This article deals with the numerical modeling, development, and performance testing of ... more ABSTRACT This article deals with the numerical modeling, development, and performance testing of a novel partial premix-type burner with a discrete porous medium using liquefied petroleum gas as fuel. The porous structure is made up of solid Al 2 O 3 spheres. The ...
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Papers by Ridzuan Zakaria