Production and characterization of activated carbon from palm shell by using microwave heating method / Roozbeh Hoseinzadeh Hesas

Activated carbon (AC) demonstrated significant adsorption of pollutants in gas and liquid phases due to its high micropore volume, large specific surface area, favorable pore size distribution, thermal stability, capability for rapid adsorption and low acid/base reactivity. Palm shell (agricultural waste) is used as a raw material in this study due to its inherent characteristics such as high carbon content, low ash, and almost negligible sulfur content. In the present work, microwave heating was applied instead of conventional heating techniques as a heat source of AC preparation. This method reveals higher sintering temperatures and shorter processing times which result in higher efficiency and more energy saving. The effects of significant parameters such as microwave radiation time and power level, different types of chemical and physical agents, chemical impregnation ratio and particle size in production of ACs were investigated. Accordingly, the effects of these variables on the structural and surface chemical properties of the ACs were explored. Several methods of characterization were utilized to examine the prepared ACs including nitrogen adsorption-desorption at -196 °C, proximate and ultimate analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Moreover, CO2 adsorption at different temperatures and methylene blue (MB) adsorption were carried out. The response surface methodology was used to optimize the preparation conditions of palm shell based ACs with microwave heating methods by zinc chloride chemical activation. The influence of variances on MB adsorption capacity and AC yield was investigated. Based on the analysis of variance, microwave power and microwave radiation time were identified as the most influential factors for AC yield and MB adsorption capacity, respectively. In this study, effects of different heating methods of microwave and conventional on textural and surface chemical properties of the ACs were compared. The ZnCl2 chemical activation at different weight ratio of ZnCl2 to precursors were applied. The results indicated that for both the microwave and conventionally prepared samples, the BET surface area (SBET) is enhanced to a maximum value at optimum impregnation ratio and then decreased with further increases in the agent ratio. The total pore volume in the microwave samples increased continuously with increasing zinc chloride, while in the conventional samples, the total pore volume increased up to the optimum impregnation ratio and then decreased. Oil palm shell based ACs were also prepared using KOH as an activation agent under the microwave irradiation. The effects of the activation time, chemical impregnation ratio and microwave power on the AC properties were investigated. To study the effects of the nature of the physical agent, the impregnated precursors were activated under a flow of carbon dioxide or nitrogen. The results demonstrates that the CO2 activation requires a shorter activation time to reach the maximum SBET than the activation under N2 since CO2 reacts with the carbon to develop the porosity

Thermodynamic evaluation of distillation columns using exergy loss profiles:a case study on the crude oil atmospheric distillation column

This paper presents a case study on the crude oil atmospheric distillation column of Tabriz refinery plant to show the applicability of exergy loss profiles in thermodynamic examination of the different retrofit options. The atmospheric distillation column of Tabriz refinery has been revamped as a consequence of increase of the plant capacity to 100,000 bpd. To cover the deficit of feedstock of the revamped unit, a blend of the existing feedstock with imported crude oil is used as a feedstock. However, to investigate how the blend of these two different types of crudes as a feedstock has an influence on the operating conditions, the examination of the column is needed. Exergy as a comprehensive thermodynamic property which translates the temperature, pressure and composition change into a common unit has been chosen to evaluate the distillation column thermodynamically. Furthermore, the exergy loss profile of the base case serves as a scoping tool to pinpoint the source of inefficiencies. Then, the exergy loss profile as a screening tool has found the retrofit options which are likely to yield greatest energy saving from a list of retrofit options proposed by the industrial partner. In the presented case study, the exergy loss profile identifies the best retrofit option with 17.16% reduction in exergy losses, which finally lead to 3.6% reduction of primary fuel demand

Microwave-assisted production of activated carbons from oil palm shell in the presence of CO2 or N2 for CO2 adsorption

Activated carbon (AC) was prepared from oil palm shell using different ratios of KOH as an activation agent and various microwave irradiation powers. To study the effects of physical agents, the impregnated precursors were activated under a flow of CO2 or N2. Maximum BET surface areas of 1196 and 1630m2/g were achieved in the presence of CO2 and N2, respectively. The textural properties of the samples with the highest surface areas were investigated using ultimate and proximate analyses, SEM and FTIR. The CO2 adsorption results suggest that the ACs are promising adsorbents for gas separation or storage applications

An investigation on the capability of magnetically separable Fe₃O₄/mordenite zeolite for refinery oily wastewater purification

Damage to the water resources and environment as a consequence of oil production and use of fossil fuels, has increased the need for applying various technologies and developing effective materials to remove contaminates from oily wastewaters resources. One of the challenges for an economic industrial wastewater treatment is separation and reusability of the developed purifying agents. Development of magnetic materials could potentially facilitate easier and more economic separation of purifying agents. Therefore, herein we have synthesised an efficient and easily recyclable Fe3O4/mordenite zeolite using a hydrothermal process to investigate its purification capability for wastewater from Kermanshah oil refinery. The synthesised Fe3O4/mordenite zeolite was characterised using XRD, FTIR, SEM, EDX, XRF and BET analysis. XRD result showed that the synthesised Fe3O4/mordenite zeolite comprised sodium aluminium silicate hydrate phase [01-072-7919, Na8(Al6Si30O72)(H2O)9.04] and cubic iron oxide phase [04-013-9808, Fe3O4]. Response Surface Method (RSM) combined with Central Composite Design (CCD) was used to identify the optimum operation parameters of the pollutant removal process. The effect of pH, contact time and Fe3O4/mordenite zeolite amount on the Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Nephelometric Turbidity Unit (NTU) were investigated. It was found that pH was the most significant factor influencing COD and BOD removal but the quantity of Fe3O4/mordenite zeolite was the most influential factor on the turbidity removal capacity. The optimum removal process conditions were identified to be pH of 7.81, contact time of 15.8 min and Fe3O4/mordenite zeolite amount of 0.52% w/w. The results show that the regenerated Fe3O4/mordenite zeolite can be reused for five consecutive cycles in purification of petroleum wastes