Engineering and Technology Journal

This study aimed to investigate the effects of phosphogypsum addition on ceramic membrane properties. In this regard, clay and phosphogypsum were characterized using FTIR and laser particle sizer. The ceramic paste was prepared by incorporating varying amounts of phosphogypsum (10 to 50%), followed by molding using a semidry-pressing process at 10 bars pressure and sintering temperature at 900℃. The raw materials and prepared membranes were analyzed using FTIR, laser particle size, contact angle, porosity, and mechanical strength to evaluate the properties of the resulting ceramic membranes. The study showed that as the amount of phosphogypsum increased from 10% to 50%, the membrane's hydrophilicity significantly increased, while its mechanical strength decreased by 35% and porosity increased by 26%. Moreover, the permeability of distilled water also showed a significant increase of 67% when the amount of phosphogypsum was increased from 10% to 50%.These observations suggest that phosphogypsum can significantly influence ceramic membrane properties, which may have implications for its use in various membrane applications. The findings of this research contribute to our understanding of the potential use of phosphogypsum as a valuable material for ceramic membrane production, with important implications for sustainable waste management practices. Future studies can focus on exploring the suitability of these ceramics for various applications and their environmental impact.

A self-tuning hierarchical controller in which a Fuzzy logic controller supervises the control actions of a conventional PID has been proposed, implemented and presented in this paper. The controller has been applied to a control study of Fluid Catalytic Cracking unit (FCCU) riser temperature, and regenerator temperature respectively. Comparison between the performance of the proposed Fuzzy-PID controller and the conventional PID was made in simulation studies of regulatory and servo performances of the two controller types. Six performance measures: Percent overshoot (OS), settling time (ST), integral absolute error (IAE), integral square error (ISE), integral time absolute error (ITAE) and integral time square error (ITSE) were employed as the tools for performance comparison between the conventional PID and the Fuzzy-PID controller. For the tracking of riser temperature with a set point at 524℃, the performance indicators under PID control gave the following results overshoot (14.5%); settling time (40 seconds) Integral absolute error (8.246), integral square error (3.3); integral time absolute error(1762);integral time square error (43.77) while for the same indicators under Fuzzy-PID control the following values: overshoot (3.3%); settling time (40 seconds) ;Integral absolute error (8.811); integral square error (14.5); integral time absolute error(280),;integral time square error (31.11) .The results allude to the superiority of the fuzzy-PID scheme over the PID scheme in tracking the optimal set point of riser temperature. More so, for tracking the regenerator set point temperature of 746oC, comparative study of step response under the two schemes gave the following results in six performance indicators: overshoot (PID (12.6%) / Fuzzy-PID (6%)); settling time (PID (80 seconds) / Fuzzy-PID (20seconds)); Integral absolute error (PID (14.29) / Fuzzy-PID (8.63)); integral square error (PID(6.713). Fuzzy-PID (4.506)); integral time absolute error(PID(2858)/Fuzzy-PID(305.9)), integral time square error (PID(77.55)/Fuzzy-PID(33.05)) . Moreover, the fuzzy-PID controller also showed superior performance over the conventional PID controller in terms disturbance rejection (regulatory response) of both riser and regenerator temperature. The results from this study suggest that the application of fuzzy-PID scheme to temperature control offers good promise of improved fluid catalytic cracking unit (FCCU) operations.

Radioactive waste poses significant risks to human health and the environment due to the emission of gamma rays, beta particles, and alpha particles from natural or artificial radioactive elements. This paper reviews the essential sources of radioactive waste, their potential risks to humans and the environment, their classification depending on their chemical, physical, and radiological features, and the treatment techniques utilized to prevent them from leaking into the environment. In addition, the current study focuses on using membranes exclusively and membrane technologies in the remediation of radioactive liquid wastes. The use of pressure-driven membrane technologies, such as reverse osmosis, nanofiltration, ultrafiltration, and microfiltration, is particularly emphasized. Additionally, the use of nanomaterials like titanium dioxide, zinc oxide, silica, alumina, silver oxide, zeolite, copper ferrocyanides, and carbon nanotubes embedded with membranes to improve their effectiveness and enhance their applicability decreases the risks associated with radioactive contamination via modifying membrane properties including flow rate, the result of rejecting radioactive particles dissolved or suspended in contaminated water, hydrophobic and hydrophilic membrane's ability and among other properties. Moreover, incorporating nanoparticles into reinforced membranes enhances the mechanics of nanocomposite membrane surfaces via processes like adsorption and ion exchange with various radioactive ions. Besides increasing nanocomposite membranes' performance in reducing the hazardous radionuclides effects, it modifies membrane properties, such as enhancing antibacterial capabilities, antifouling, mechanical stability, and thermal stability. The article review also discusses hybrid pressure-driven membrane processes in disposing of radionuclides generated in nuclear power plants, hospitals, research facilities, and decontamination projects to protect human health and the environment

Y-zeolite catalyst, with a Si/Al ratio of 2.23 and a high surface area of 703.34 m2/gcat, was prepared with three different particle sizes: 75, 600, and 1000 μm, from commercial Ludox AS-40 colloidal silica 40 wt.% suspension in water using the hydrothermal method. Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analyses were all utilized to analyze the properties of the synthesized Y-zeolite catalyst. Waste cooking oil (WCO) was transesterified to biodiesel in a batch reactor under different temperatures (e.g., 40, 50, and 60℃) for 3 hours, and the activity of the catalyst was evaluated before and after being loaded with potassium oxide (K2O) molecules using the impregnation method. It is observed that the biodiesel conversion and yield, in the presence of a non-KOH-loaded catalyst, rose with increasing temperature and/or reaction time. However, increasing the reaction time beyond 2 hours in the presence of the catalyst loaded with 10% KOH decreased biodiesel conversion and yield. It has also been found that using catalysts with smaller particle sizes (e.g.,75 μm) is more favorable for enhancing the conversion of the catalytic process due to the acceleration of the reaction rate. A maximum biodiesel yield and conversion of 84.44% and 80%, respectively, were obtained. Using Gas Chromatography-Mass Spectrometry (GCMS), the composition and physical characteristics of the produced biodiesel were compared with those of standard fuels and the comparison results were particularly satisfactory. The spent Y catalyst loaded with KOH was recovered, reactivated, and reused in subsequent reactions. It exhibited outstanding catalytic activity, which is a testament to its cost advantage since it could significantly reduce the need for large quantities of costly homogeneous catalysts that are difficult to separate from the reaction products.

In various chemical industrial applications such as hydrocracking, drying, and Fischer-Tropsch, the utilization of fluidized bed systems is prevalent. Efficient heat transfer is crucial for maintaining stable temperatures and ensuring product quality in industrial processes. Gas-solid fluidized beds, which involve gas circulation through a bed of solid particles, offer a means to achieve efficient heat exchange. However, factors such as particle size, gas velocity, and heating methods can influence the effectiveness of these systems. To investigate the impact of internal heating on heat transfer in gas-solid fluidized beds, an experimental study was conducted using glass beads of 200 and 600 μm. A Perspex fluidization column with an inner diameter of 10 cm and a total height of 2 m was packed with these beads. The experiments were performed under superficial gas velocities ranging from 0.1 to 0.5 m/s. Highly responsive sensors were employed to measure temperatures and calculate the heat transfer coefficient. Additionally, the position of the heating element and local heat transfer coefficients at different gas velocities were examined. The experimental results were compared to a mathematical model developed to simulate laboratory findings. The total heat transfer coefficient was evaluated in a gas-solid fluidized bed at different bed temperatures. Furthermore, a comparison was made between the experimental results and the model to validate the practical application, while the practical results were also compared with previous studies