Gamma Photon Column Scanning of Prototype and Industrial Distillation Columns

Monte Carlo simulation of gamma photon transport and interaction with the distillation column and its contents was performed in order to predict the effects of gamma photons when they interact with matter. The results of the interaction and transport of gamma photons are presented as energy deposition on the distillation column and its contents. Energy attenuation was more pronounced on the column walls and trays as compared to the region between the trays, where there is mostly vapour space. Gamma column scanning was then used to verify the Monte Carlo simulation results by scanning and investigating the integrity of two laboratory prototype distillation and industrial distillation columns. One of the prototype distillation columns was 1 m tall with four trays and the other one was 1.8 m tall consisting of six trays and a packed bed. Commonly encountered distillation column malfunctions such as collapsed tray, weeping, flooding and foaming were simulated in the two prototype distillation columns and scanned. The industrial distillation column was a 26 m tall benzole prefractionator column, consisting of 60 single pass trays and a diameter of 0.8 m. A 10 mCi 60Co gamma radiation source and NaI(Tl) scintillation detector were used to scan the distillation columns. The results from the two prototypes showed that all the simulated malfunctions were clearly detected except for foaming. The results from industrial distillation column showed that all the trays were in their correct position although tray number 32 could be partially damaged and just below tray 41, the scan revealed that there was a loss of column wall thickness. The obtained density profile for the industrial distillation column showed some small variations from the expected density profile and this was attributed to external features on the distillation column and wind bursts that shifted the source and detector from the chosen scan line orientation.

Gamma Photon Column Scanning of Prototype and Industrial Distillation Columns

Monte Carlo simulation of gamma photon transport and interaction with the distillation column and its contents was performed in order to predict the effects of gamma photons when they interact with matter. The results of the interaction and transport of gamma photons are presented as energy deposition on the distillation column and its contents. Energy attenuation was more pronounced on the column walls and trays as compared to the region between the trays, where there is mostly vapour space. Gamma column scanning was then used to verify the Monte Carlo simulation results by scanning and investigating the integrity of two laboratory prototype distillation and industrial distillation columns. One of the prototype distillation columns was 1 m tall with four trays and the other one was 1.8 m tall consisting of six trays and a packed bed. Commonly encountered distillation column malfunctions such as collapsed tray, weeping, flooding and foaming were simulated in the two prototype distillation columns and scanned. The industrial distillation column was a 26 m tall benzole prefractionator column, consisting of 60 single pass trays and a diameter of 0.8 m. A 10 mCi 60Co gamma radiation source and NaI(Tl) scintillation detector were used to scan the distillation columns. The results from the two prototypes showed that all the simulated malfunctions were clearly detected except for foaming. The results from industrial distillation column showed that all the trays were in their correct position although tray number 32 could be partially damaged and just below tray 41, the scan revealed that there was a loss of column wall thickness. The obtained density profile for the industrial distillation column showed some small variations from the expected density profile and this was attributed to external features on the distillation column and wind bursts that shifted the source and detector from the chosen scan line orientation.

Investigating on a Process Method of Beneficiating and Increasing the Graphite Purity to 99% Grade

The main aim of this project was to come up with an efficient method for the purification of graphite to at least 99%. There has been an increasing demand for high-grade graphite products with up to 99.99% carbon that has resulted in the development of various approaches to remove impurities even to parts per million range. Removal of impurities from 94% graphite is important to achieve a high-purity graphite product. Microwave irradiation was used to prepare high-purity graphite from 94% graphite concentrate. The results showed that microwave irradiation could enhance the fixed carbon of flake graphite to a higher level. Under the optimum conditions selected of 4 minutes’ reaction time and 100% microwave output (800 W), a graphite product with a fixed carbon content of 98.845% was obtained from flake graphite concentrate. According to XRD, FTIR and Handheld XRF analysis, impurities mainly composed of Fe, Co, Sr and Zr were present before treatment. After treatment under optimum conditions Fe, which was the major impurity in the sample was reduced from 3.566% to 1.031%. The ash content of graphite under optimum conditions was 1.55%. The crystal structure of flake graphite showed no change. It can be concluded from this study that graphite purification using microwave irradiation increases the carbon content of graphite.

Investigation on the Potential Production of Diesel from Waste Tires

An alternative fuel production was performed by catalytic-pyrolysis of waste tires under a nitrogen (N2) environment and with a zeolite catalyst. Pyrolysis of scrap tires has been pointed out as an alternative to the incorrect disposal of tire wastes. Pyrolysis processes can produce tire-derived oils that may be used as fuel or added to conventional fuels, producing fuel blends with improved properties and reduced cost. The pyrolysis process can contribute to removing tire residues from inadequate sites and it can be a sustainable process to produce alternative fuels. The project investigated the conversion of the waste tires into diesel as one way of waste management and also as a viable process which in turn helps to meet the fuel demand. Uses of the diesel and the by-products from the process were also outlined. Experiments were conducted on the pyrolysis process in order to find the optimum conditions for producing the diesel through pyrolysis;the temperature and residence time were optimized in order to get maximum output from the process. The optimum temperature of the reaction was found to be 520˚C and the optimum residence time was 92.5 minutes. Quality tests of the product were then conducted on the obtained product and most of the properties were found to meet the required standard specifications. The most critical properties which are density, final boiling point, flash point and kinematic viscosity, were found to be 0.8495 g/cm3, 370˚C, 50.5˚C and 3.681 cSt, respectively, and they were within the required specifications. Quality analysis showed that a quality product that is suitable for automobiles could be obtained from the process. The process also produces useful by-products such as char, which can aid in the purification process of the diesel after conversion to activated carbon. The process is environmentally friendly if the appropriate pollution prevention methods like gas absorption are thoroughly implemented. Waste tires are an alternative source of diesel and hence the feasibility of implementing the project on a large scale.

Adsorption of Chromium (VI) Using Nano-ZnO Doped Scrap Tire-Derived Activated Carbon

Nowadays, nano mineral modified biochars show a promising adsorption capacity for pollutants removals by combining the advantages of porous structure of biochar and unique property of nano minerals. In this work, nano-zinc oxide doped scrap tire derived activated carbon (nZnO-STAC) was synthesized by wetness impregnation method. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models while the kinetics of the process were examined using Lagergren Pseudo-first and second order, intraparticle diffusion and Elovich kinetic models. Characterization of the activated carbon by Powder X-ray Diffraction (PXRD). The surface groups present on the activated carbon surface were determined using the Fourier Transform Infra-Red Spectroscopy (FTIR) analysis. Optimization studies were carried out to determine the effects of pH, initial metal concentration, adsorbent dosage, contact time and adsorbent particle size on the Cr (VI) removal efficiency. The results showed optimum Cr (VI) removal at pH 3, 10 mg/L concentration, 120 minutes of contact using 1000 - 1400 μm adsorbent particle size at a dosage of 2.5 g/L. The adsorbent structure was found to be predominantly amorphous. The chromium removal efficiency of the adsorbent was around 81.6%. Of the tested kinetic models, the pseudo-second order model exhibited the best fit with the experimental data with an R2 value of 0.9744. This study clearly demonstrates the feasibility of using the nano-ZnO doped scrap tyre derived activated carbon adsorbent for the remediation of chromium (VI) polluted industrial wastewaters.