M. A. Mohd Salleh

An innovative procedure for large-scale synthesis of carbon nanotubes by fluidized bed catalytic vapor deposition technique

After the efforts of the first decade, scientists and technicians are facing the big challenge of going from laboratory studies to the large scale production of carbon nanotubes (CNTs) and their ultimate commercial applications. Therefore, innovations in the CNT manufacturing process and its engineering are strongly required. To this contribution, a new technique for the mass production of CNTs by fluidized bed catalytic chemical vapor deposition (FBCVD) has been developed. The CNTs synthesis reactions were carried out in the presence of iron‐cobalt supported on alumina as a catalyst and ethanol as the source of carbon at 600°C. The product was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X‐ray diffractometry (XRD). The results revealed that this technique offers the fabrication of large quantities of CNTs which has the important quality of being free from large amorphous carbon, open‐ended with narrow diameter distribution, and having good morphology with few defects. The proposed design has other remarkable advantages, such as simplicity, low cost, energy savings, completely controllable and easy to scale‐up, which make it suitable for industrial scale production.

Effect of Experimental Variables on the Combustion Characteristics of Water-in-Diesel Emulsion Fuels

Water-in-diesel (W/D) emulsion fuels were prepared through an ultrasonic processor by using high energy emulsification method. Accordingly, the physical and chemical properties were analyzed. A decrease in viscosity was found in the emulsion fuel in contrast to the neat diesel which signifies the enhanced fluidity of the fuel. The emulsion fuel was then used to carry combustion tests in an internal combustion engine. A decrease in exhaust temperature was observed when a high surfactant to water ratio was used, which lead to minimal heat loss. As water is emulsified with diesel, effectiveness of combustion is improved rather than neat diesel fuel. It was also explored that the addition of water-in-diesel is influential in terms of reduction in exhaust gas emission such as carbon dioxide, carbon monoxide, ammonia from the internal combustion engine. Therefore, this type of emulsion fuel would be a useful contribution in the fuel economy, but also in making it environmentally friendly since diesel fuel is now considered one of the leading fuels causing ecological contamination.

Effect of Equivalence Ratio and Particle Size on EFB Char Gasification

In this study, the effects of equivalence ratio and biochar particle size on high heating value, gas composition, carbon conversion, and gas production from the empty fruit bunch biochar were experimentally investigated in a fluidized bed reactor. Equivalence ratio varied from 0.1 to 0.34, while the size varied from 0.2 mm ≤ s ≥ 1 mm. It was observed that the syngas production increased as the air flow rate increased until equivalence ratio was equivalent to 0.24 and finally decreased with increasing equivalence ratio. In addition, the high heating value of syngas also decreased as equivalence ratio increased. The increase in the particle size from 0.2 mm ≤ s ≥ 1 mm decreased the H2 yield from 34.75 to 25.3%, and decreased the overall syngas production and high heating value. The produced syngas revealed a high heating value in the range of 22.6–52.9 MJ/KG. Meanwhile, the maximum char to gas conversion efficiency achieved was 80.2%. A hydrogen-rich gas was successfully produced through air gasification at an average yield of 25.3% H2, 5.20% CO, 2.12% CH4, and 3.10% CO2. Hence, it can be concluded that the thermochemical gasification technique provided a promising route for syngas production under optimized conditions.