• Energy Research

The influence of the Si/Al ratio of ZSM-5 on 10 wt% Ni/ZSM-5.SAPO-11 catalysts were investigated through the palm oil hydrodeoxygenation (HDO) process, based on the product selectivity of alternative jet fuel. This study utilizes a 1 L batch reactor at 60 bar and 350 degrees C for palm oil hydrodeoxygenation over 10 wt% Ni/ZSM-5.SAPO11 catalysts. Si/Al ratio of 50 produces a 10 wt% Ni/ZSM-5.SAPO-11 catalyst with the optimum physicochemical properties for palm oil hydrodeoxygenation. TGA/DTG analysis of the spent catalyst shows that the catalyst has good thermal and catalyst stability with minor carbon deposition. GC/MS analysis also demonstrated a 100 % palm oil conversion to alternative jet fuel. The highest jet fuel yield of 51 % was attained with a Si/Al ratio of 50. The physicochemical properties of alternative jet fuel samples were measured to ensure that the conventional fuel standard limits were appropriately followed. These results indicated that such types of bifunctional Ni-based catalysts have the potential to be used in the conversion of triglycerides to alternative jet fuel.

The kinetics of the torrefaction process have been studied in various reactors. However, no study reported the torrefaction kinetics of organic municipal solid waste (OMSW) in a helical screw rotation-induced (HSRI) fluidized bed reactor. This study produced torrefied solid fuel, and the kinetic parameters of the OMSW torrefaction process were determined. The results showed that increasing temperature and residence time from 200 to 300°C and 0 to 40 minutes increased mass loss, calorific value, ash content, fixed carbon, energy density, and carbon content. Conversely, mass yield, volatile matter, energy yields, oxygen-to-carbon, and hydrogen-to-carbon ratios decreased. The calorific value experienced notable growth, varying from 17.80 to 26.18 MJ/kg, with increased residence time and temperature. The one-step kinetic model using a first-order reaction accurately predicts reaction data for long residence times with a maximum error of 2.42% at 300°C and 10 minutes and is useful for designing and scaling up the HSRI fluidized bed reactor within the temperature and mass loss ranges of 220–300°C and 2.61–47.38%. The OMSW torrefaction frequency factor and activation energy were 0.2036 s−1 and 24.46 kJ/mol, respectively. The findings of this study showed that residence time has less effect on the torrefaction process than temperature.

The potential of producing high calorific value (CV) solid fuel was investigated in a helical screw rotation-induced (HSRI) fluidized bed reactor based on mechanical fluidization. The study revealed that the HSRI torrefaction improved the torrefied product properties. For the 40 and 0 rpm conditions, the CV, fixed carbon, and ash contents of torrefied solid fuel increased with an increase in temperature. In contrast, volatile matter, moisture content, mass and energy yields decreased. The CV of torrefied solid fuel increased by a factor of 1.43 and 1.58 at 280 °C for the 40 and 0 rpm conditions, respectively. HSRI torrefaction enhanced the removal of hydroxyl functional group. HSRI torrefaction improved the hydrophobicity of the torrefied solid fuel. Therefore, the HSRI fluidized bed reactor promotes uniform temperature distribution, a higher heat transfer rate within the sample particles in the reactor, and a homogenous torrefied solid product compared to the fixed bed reactor.

The use-and-throw culture of plastic products has generated a massive amount of plastic wastes each year, posing a threat to the environment with the absence of proper disposal methods of the wastes. Conventional disposal methods including landfill and incineration cease to be the ultimate solution to the problem, in addition to further causing soil and air pollution. Liquefaction technology has emerged to become one of the alternatives in reducing the amount of accumulated wastes simultaneously generating valuable liquid products for applications such as transportation fuel and chemical feedstock in industries. Additionally, the recovery of plastics through this method poses great potential in reducing the dependency on non-renewable fossil fuels, creating an alternative energy source. This review exploits the liquefaction of common types of plastics found in the wastes and some key parameters affecting the yield and properties of end products including the type of reactor, temperature, pressure, reaction time, types of solvent, solvent to plastic ratio and the initial size of plastic used.

Abstract The rapid increase in population has been identified as one of the main reasons for the abundance generation of municipal solid waste (MSW), which could be advantageous when converted to energy. Utilizing MSW as a renewable fuel in waste-to-energy conversion technologies provides solutions to depleting fossil fuel reserves, reduces the effect of pollution on human health, and reduces the pressure on land for landfills. The urgent interest in renewable energy generation has recently promoted the utilization of MSW as a renewable and sustainable fuel for thermochemical processes, which is in line with the United Nations' low carbon footprint targets. However, to efficiently harness MSW as fuel for combustion, pyrolysis, and gasification, curbing limitations, such as high moisture content, low calorific value, poor grindability, poor combustion characteristics, low energy density, low H/C and O/C ratios of the MSW is paramount. An effective way to curb these is to pretreat the MSW. Torrefaction is a greener and promising thermochemical process frequently applied for pretreating different biomass resources to curb the MSW limitations. Nonetheless, this process is yet to be profoundly described for MSW and other types of biomass. Therefore, in this review, the influence of torrefaction process parameters on the properties of MSW and other types of biomass was evaluated. The properties of MSW as a raw material for torrefaction process were also presented. Furthermore, the classification of different types of reactors for torrefaction process and potential applications of the torrefied MSW (solid biofuel) were discussed.

One effective method to minimize the increasing cost in the construction industry is by using coal bottom ash waste as a substitute material. The high volume of coal bottom ash waste generated each year and the improper disposal methods have raised a grave pollution concern because of the harmful impact of the waste on the environment and human health. Recycling coal bottom ash is an effective way to reduce the problems associated with its disposal. This paper reviews the current physical and chemical and utilization of coal bottom ash as a substitute material in the construction industry. The main objective of this review is to highlight the potential of recycling bottom ash in the field of civil construction. This review encourages and promotes effective recycling of coal bottom ash and identifies the vast range of coal bottom ash applications in the construction industry.

Abstract This study proposes a design of polygeneration system based on solid oxide fuel cell to supply electricity, hot water, cooling, and hydrogen. This system also integrates the stationary supply for electric and hydrogen cars. The polygeneration system is developed based on energy, economic and environment simulation models by taking into account its application for the residential building. Four system configurations were designed based on the grid connection and the vehicle type and subsequently evaluated to determine the performance of the system in regard to the criteria such as efficiency, reliability, primary energy saving, cost saving as well as carbon dioxide reduction. Moreover, a strategy of selling the available hydrogen was also considered to analyze the competitiveness of the proposed system with the conventional separated system. Depending on these criteria, analysis of fuel cell size with respect to the coverage of demands was also conducted. The proposed system achieved primary energy savings, cost saving and emission reduction of about 73%, 50% and 70% respectively. The hydrogen selling strategy has a significant effect in reducing energy cost close to 51% for the configuration with electric vehicle station.