Ahmad Rafizan Mohamad Daud

The effects of polymer and surfactant on polymer enhanced foam stability

Polymer addition to foam has been proposed to enhance foam stability. Polymers can be used as a viscosifying agent of the aqueous surfactant solution of the external phase of foam, increasing apparent foam viscosity and thus reducing foam drainage rate. In this study a high and low molecular weight of partially hydrolyzed polyacrylamide polymer were used as the viscosification agent. Two ionic surfactants including Sodium dodecyl benzene sulfonate (SDBS) and Sodium dodecyl sulfate (SDS) were also used as the foaming agent. All solutions were also prepared in fresh water and 2-wt% NaCl to emphasize the effects of salt presence on foam stability. Experimental results showed that both SDS and SDBS surfactants were compatible with polyacrylamide polymer addition and promising results were achieved. Higher molecular weight polymer was more effective than lower molecular weight and produced foams were more stable when high molecular weight polymer was used. Foam stability was in a direct relationship with polymer addition and increasing polymer concentration enhanced foam stability in all solutions.

Calcium Carbonate Production through Direct Mineral Carbon Dioxide Sequestration

Mineral carbon dioxide sequestration provides a leakage free and permanent method of CO2 disposal to produce environmentally benign and stable solid carbonates. FGD gypsum as a source of calcium was proposed as the potential feedstock in this study. The purpose of this laboratory study was to investigate the effects of reaction parameters such as CO2 pressure, reaction temperature, particle size, and ammonia solution concentration on calcium carbonate purity through Merseburg process. Increasing the reaction temperature as well as the pressure was very effective in improving the calcium carbonate purity. High purity calcium carbonate was produced when reaction temperature and CO2 was increased to 400 °C and 70 bar, resulting in 93% and 94% purity, respectively. Experimental results showed that reducing particle size was also effective in enhancing the calcium carbonate purity in which the smallest particles produced higher purity calcium carbonates rather than larger particles. The role of ammonia solution on calcium carbonate purity was found to be beneficial in improving the calcium carbonate purity in which increasing the ammonia solution increased calcium carbonate purity significantly in all experiments.

Epoxidation of palm kernel oil-based crude oleic acid

Most vegetable oils have high content of unsaturated bond and can be converted into epoxidized fatty acids. These days, epoxidized vegetable oils are great concern as they are obtained from sustainable, renewable natural resources and are environmental friendly. The epoxidation of palm oleic acid was carried out by using in situ generated performic acid (HCOOOH) to produce epoxidized oleic acid. The degree of temperature, the molar ratio of formic acid or hydrogen peroxide and types of catalyst was considered. Epoxidation results were based on complete conversion oxirane, rate of epoxidation and stability of the oxirane. It was found that a maximum relative conversion oxirane (RCO) of epoxide is 88% at optimal condition.

Mechanical pretreatment of lignocellulosic biomass for biofuel production

Lignocellulosic biomass (LB) sources which are readily available in abundance are widely considered as a potential future sustainable raw materials for biofuel production. Typically, biofuel production involved several chemical and mechanical steps consisting of pretreatment, hydrolysis, fermentation and separation. The pretreatment step is considered as one of the most vital part of the whole processing scheme due to the impact it had on the efficiency of the subsequent processing steps. In this study we reviewed the mechanical pretreatment of LB focusing mainly on the size reduction technique by grinding process. Grinding is one of the proven preliminary pretreatment techniques employed in biomass conversion to liquid biofuel. However, this technique is known to be costly due to high energy consumption. In view of this, an efficient and cost effective pretreatment technology is required in order for the biofuel to be produced at a competitive level. At the same time, the impact on environment caused by the conventional pretreatment processes can be minimized. Thus, a new combined chemical-mechanical pretreatment is considered whereby a green ionic liquid (IL) solvent is introduced.

Synthesis of Modified Covalent Organic Framework-1 (COF-1) and Its Characterizations

Three samples of covalent organic framework-1 (COF-1) assigned as COF-1 (S1), COF-1 (S2) and COF-1 (S3) were prepared by varying the initial mass of 1, 4-benzene diboronic acid (BDBA) used. The samples were characterized using Nitrogen adsorption for porosity analysis and XRD for crystallinity analysis. All samples exhibit Type IV isotherm indicating mesoporous materials. The BET surface area value showed an increasing trend with increasing mass of BDBA used. The highest BET surface area was recorded by COF-1 (S3) with a value of 107.9 m2/g. This sample has the highest amount of micropore volume of 66 % and the lowest average pore diameter of 11.05 nm. XRD patterns revealed sharp peaks indicating a crystalline structure and the peak positions matched well with other works available in literature. The difference in intensities however was due to the exposure of the samples to atmosphere resulted in the re-formation of COF-1 structure onto BDBA structure.

An Investigation into the Combustion of Mixed Fuel Consisting of Bituminous Coal and Crude Bio-oil

The combustion of bituminous coal, bio-oil, and their slurry mixtures were performed under air atmosphere using Thermogravimetric Analyzer (TGA). All samples were run from room temperature to 110°C and held for 10 minutes before the temperature was ramped to 1100°C and held again for 10 minutes at 1100°C at the heating rate of 10°C/min and gas flow rate of 50mL/min. Kinetic evaluation was conducted using a simple Arrhenius-type kinetic model with first-order decomposition reaction. Apparent activation energy, Ea, and pre-exponential factor, A, were calculated from the modelling equation. Results reveal that the reactivity of CBS fuel is higher than a single coal fuel to which the addition of bio-oil helps to increase the combustion performance of the blends. The optimum fuel ratio appears at 50:50 ratio with equal contribution of coal and bio-oil properties that contribute to the increase in volatile matter causing maximum combustion rate achievable at much lower temperature compared to single coal fuel.

Parametric influence on the physical characterizations of covalent organic framework-1

Four samples of covalent organic framework-1 (COF-1) assigned as S1 to S4 were prepared by varying the initial mass of 1,4-benzene diboronic acid (BDBA) used and heating condition. The samples were physically characterized using Brunauer–Emmett–Teller (BET) surface area analysis and FESEM analysis. The BET surface area value showed an increasing trend with increasing mass of BDBA used. The highest achievable BET surface area is recorded by COF-1 (S3) with a value of 107.9 m2/g. The low surface area obtained is likely due to the distribution of particles with large pore sizes. This is confirmed by the Field Emission Scanning Electron Microscopy (FESEM) images which correlate well with the surface area obtained. The presence of dendrites phase within the COF-1 structure also indicates incomplete formation of a crystalline structure, hence contributed to the low surface area achieved. It was also found that the use of ramping heating did not significantly influence the formation of COF-1 crystalline structure which promotes the surface area.

Thermal behaviour of slurry prepared from clermont bituminous coal and oil palm empty fruit bunch bio-oil

Investigation on the pyrolysis behaviour of coal-biooil slurry (CBS) fuel prepared at different ratios (100:0; 70:30; 60:40;0: 100) were conducted using a Thermogravimetric Analyzer (TGA). The selected coal sample was Clermont bituminous coal (Australia), while Empty Fruit Bunch (EFB) was used as source of bio-oil that was thermally converted by means of pyrolysis. Thermal degradation of CBS fuel was performed in an inert atmosphere (50mL/min nitrogen) under non-isothermal conditions from room temperature to 1000°C at heating rate of 10°C/min. The proportions of CBS fuel at 70:30 and 60:40 blends were observed to have influenced the fuel properties of the slurry. The addition of bio-oil will shift the temperature region towards early devolatilization. Meanwhile, the thermal profiles of the blends, showed potential trends that followed the characteristics of an ideal slurry fuel where highest degradation rate was found at the blend ratio of 60:40 biooil/coal. These findings can be useful to the development of a slurry fuel technology for application in the vast existing conventional power plants.

Fuel properties of bituminous coal and pyrolytic oil mixture

Investigation on the thermal decomposition kinetics of coal-biooil slurry (CBS) fuel prepared at different ratios (100:0,70:30,60:40,0:100) was conducted using a Thermogravimetric Analyzer (TGA). The materials consisted of Clermont bituminous coal (Australia) and bio-oil (also known as pyrolytic oil) from the source of Empty Fruit Bunch (EFB) that was thermally converted by means of pyrolysis. Thermal decomposition of CBS fuel was performed in an inert atmosphere (50mL/min nitrogen) under non-isothermal conditions from room temperature to 1000°C at heating rate of 10°C/min. The apparent activation energy (Ea.) and pre-exponential factor (A) were calculated from the experimental results by using an Arrhenius-type kinetic model which first-order decomposition reaction was assumed. All kinetic parameters were tabulated based on the TG data obtained from the experiment. It was found that, the CBS fuel has higher reactivity than Clermont coal fuel during pyrolysis process, as the addition of pyrolytic oil will...