Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 14, Issue 3, 2021

The Preformed Particle gels (PPGs) have widely been used and injected in low permeability rich oil zones as diverting agents to solve the conformance issues, distract displacing fluid into out of sorts swept zones. Besides, they also reduce the permeability of thief zones and high permeability fractured zones. However, the PPG propagation and plugging mechanism are still unpredictable and sporadic in manifold void space passages. PPGs have two main abilities, first, it increases the sweep efficiency, and second, it decreases the water production in mature oilfields. However, the success or failure of PPG treatment largely depends on whether it efficiently decreases the permeability of the fluid paths to an expected target or not. In this study, the different factors were studied that affect the performance of PPG in such reservoirs. PPGs were treated in different ways; treated with brine, low salinity, and high salinity brine. Also, their impacts were investigated in low/high permeability, fractured reservoirs, and void space conduit models as well. From the literature, it was revealed that the sweep efficiency can be improved through PPG, but not displacement efficiency and little impact of PPG were found on displacement efficiency. On the other hand, Low salinity water flooding (LSWF) can increase the displacement efficiency but not sweep efficiency. Hence, based on the above issues, few new techniques and directions were introduced in this study for better treatment of PPG to decrease water cut and increase oil recovery.

Activated carbons were prepared from sewage sludge by chemical activation with pyrolusite (PAC) and lithium-silicon powder addition (LSAC) to develop effective adsorbents for the removal of Cu(II), Pb(II), Cd(II) and Cr(III) metal ions from aqueous solution. Both modifiers with an optimum dosage of 1% (wt.) were demonstrated to exhibit important effects on the formation of the adsorbent’s pore structure. PAC and LSAC showed 17.06% and 8.38% higher BET surface area than the common one without modification (AC). The XPS result showed that after modification, the hydroxyl and carboxyl groups on modified activated carbons surface were remarkably improved compared with the ordinary carbon. The adsorption results in single ion solution showed that the metal ions’ removal rates were 13~29% and 20~43%, respectively, by LSAC and PAC compared with AC’s. Adsorption isotherm and kinetics studies showed that the adsorption of heavy metal ions onto the modified adsorbents was well-fitted by the Langmuir isotherm and could be described by the pseudo-second-order kinetic model. In a multi-ions solution system, the produced carbons showed high affinity and good selective adsorptive capacity on Cu (II), Pb (II) removal, while an improvement in adsorption of Cd(II) and Cr(III) was observed. It will help a lot in wastewater industries due to its efficiency and low-price.

Background: The presence of relatively high naphthenic acid in crude oil may contribute to the major corrosion in oil pipelines and distillation units in crude oil refineries. Thus, high concentration naphthenic acid crude oil is considered to be of low quality and is marketed at lower prices. In order to overcome this problem, the neutralization method had been developed to reduce the TAN value in crude oil. In this study, crude oil from Petronas Penapisan Melaka was investigated. Methods: The parameters studied were reagent concentration, catalyst loading, calcination temperature, and reusability of the potential catalyst. The basic chemical used was 2- methylimidazole in polyethylene glycol (PEG 600) with concentration 100, 500 and 1000 ppm. Cerium oxide-based catalysts were supported onto alumina prepared with different calcination temperatures. Results: The catalyst was characterized by using Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry Analysis-Differential Thermal Gravity (TGA-DTG) to study the physical properties of the catalyst. The Ce/Al2O3 catalyst calcined at 1000°C was the best catalyst due to larger surface area formation which lead to an increment of active sites thus will boost catalytic activity. The result showed that the Ce/Al2O3 catalyst meets the Petronas requirement as the TAN value reduced to 0.6 mgKOH/g from the original TAN value of 4.22 mgKOH/g. Conclusion: The best reduction of TAN was achieved by using catalyst loading of 0.39% and reagent of 1000 ppm.

Background: Solutions to challenges of access to potable water have been the focus of many studies around the world, which also is one of the goals of sustainable development. Objective: This study attempts to address this issue wherein we tested the efficiency of blended coagulants in removing pollutants from surface water. Previous studies have reported and suggested the requirement of blended coagulants that are tailor-made for treating geographically specific water samples since single coagulants will not be effective in removing all pollutants. Methods: Three coagulants, two natural and one chemical, were blended for the present study in various ratios. Turbidity removal of the bi and tri-blend coagulants of water samples with initial turbidity of 70 and 150NTU was above 95% - 100%. Results: Removal of Physico-chemical parameters by blended coagulants in surface waters was up to 48% for electrical conductivity, 80% for total solids, 36% for hardness, 40% for alkalinity and 57% for chlorides. The results are supported with analysis from SEM images showing adsorbed floc on to coagulant and FTIR spectra presenting the functional groups responsible for coagulation. Conclusion: Hence, it can be concluded that the natural coagulants tested in the present study are promising solutions for the challenges of water quality.

Microbial fuel cells (MFCs) have been developed impressively over recent years. In order to take this technology from research to application, the performance of these systems needs to be further investigated and optimized. The electrode materials and operating conditions play a vital role in MFCs performance. In the current work, dual chamber MFC was used to investigate the performance of different electrode materials under stationary and flow conditions. Microorganism solution of Klebsiella oxytoca and Citrobacter Freundii inoculum was used in the anode chamber. Three electrode materials were investigated, namely activated carbon, graphite, and titanium. High current density and power output were obtained by activated carbon electrode and graphite, while titanium showed poor performance for bio-electricity production. The low flow velocity (or Reynolds number) in catholyte was found to enhance the energy production, while the high velocity caused a reduction in the produced current. The aeration of the cathode chamber had a negative effect on the produced current due to the transfer of dissolved oxygen to the microorganism chamber. Activated carbon showed high performance due to its high surface area with the achieved maximum power density of 462.74 mW/m2 at Reynolds number of 7030.

Aims: The efficiency of Myrtus communis leaves to eliminate Cr(VI) from aqueous solutions has been investigated. Background: Optimization, kinetic and thermodynamic studies on bio-sorption and bioreduction of Cr(VI) by Myrtus communis leaves. Objective: To eliminate Cr(VI) from aqueous solutions. Method: Batch mode studies, kinetic and thermodynamic studies. Result: The maximum bio-removal was obtained at an initial Cr(VI) concentration of 100 mg/L, biomass of 0.150 g, pH 2, and a temperature of 25°C. The modeling study has shown that the bio-removal kinetics obeyed the pseudo-second-order model along with an R2= 0.9947. Conclusion: A total removal of Cr(VI) after 60 minutes has been noticed. Also, the kinetic studies have indicated that the bioreduction of Cr (VI) to Cr (III) coupled with biosorption was produced on biomass sites. Based on the determined thermodynamic parameters (Gibbs energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0)), the bio-removal process was found to be endothermic and spontaneous in nature. Other: Myrtus communis leaves powder was characterized by spectroscopy (FTIR) and scanning electron microscope analysis (SEM-EDX).