Chemical engineering

In many porous catalyst supports, the accessibility of interior catalytic sites to reactant species could be restricted due to limitations of reactant transport through pores comparable to reactant dimensions. The interplay between reaction and diffusion in porous catalysts is defined through the Thiele modulus and the effectiveness factor, with diffusional restrictions leading to high Thiele moduli, reduced effectivess factors, and a reduction in the observed reaction rate. We demonstrate a method to integrate ceramic nanostraws into the interior of ordered mesoporous silica MCM-41 to mitigate diffusional restrictions. The nanostraws are the natural aluminosilicate tubular clay minerals known as halloysite. Such halloysite nanotubes (HNTs) have a lumen diameter of 15–30 nm, which is significantly larger than the 2–4 nm pores of MCM-41, thus facilitating entry and egress of larger molecules to the interior of the pellet. The method of integrating HNT nanostraws into MCM-41 is throug...

ZSM-5 is a promising catalyst for the catalytic fast pyrolysis (CFP) of biomass due to its high selectivity to light hydrocarbons. However, rapid deactivation of catalyst has been a major challenge towards the commercialization of CFP. The objective of our study is to evaluate the performance of MCM-41/ZSM-5 composites during the CFP of biomass. Here, for the first time, we report the synthesis of a unique MCM-41/ZSM-5 composite via a one-step, facile aerosol-based method. The composition of ZSM-5 in the composites was varied and the prepared composites were used as catalysts for the in-situ and ex-situ CFP of miscanthus × gigantus. The prepared composites were characterized by N2 adsorption-desorption, XRD, SEM, TEM and DRIFTS-pyridine adsorption. The results of CFP experiments demonstrated that ZSM-5 in the composites was fully accessible. Most importantly, MCM-41 acted as a sacrificial layer for coke deposition and decreased the deactivation rate of the ZSM-5.

... and Elijah Taiwo, Dept. of Chemical Engineering, Obafemi Awolowo University, Ile-Ife. Copyright 2009, Society of Petroleum Engineers Inc. This paper was prepared for presentation at the 33rd Annual SPE International Technical Conference and Exhibition in Abuja, Nigeria ...

... when the mean liquid film velocity at the conditions of loading is zero, eq 6 will represent this condition as Then, using eqs 10 and 12 in eq 15, the vapor velocity at load point can ... The experimental apparatus used in this work was fully described by Fasesan and Taiwo (2001). ...

Oil sludge waste associated with crude oil production generally consists of oil, sands and untreatable emulsions segregated from the production stream, and sediment accumulated on the bottom of crude oil and water storage tanks. The use of single solvent and combination (solvent blend) was evaluated for extraction of hydrocarbon content (oil) of the Tank Bottom Sludge (TBS) associated with the crude oil production with a view to optimizing hydrocarbon recovery from the sludge. TBS samples were contacted with selected solvents blends of varying volumetric ratios, each at a time. The blend generated from xylene, hexane, cyclohexane and petroleum ether representing aliphatic and aromatic interactive combination with varying polarity. Their effects on the oil recovery from tank bottom sludge were determined, with solubility parameter as a factor. The optimum oil recovery by blend A, B and C at room temperature of 29°C, from sample 1 are respectively 54.48% (3:2), 60.33% (2:3) and 61.10%...

Alteration of thermodynamic equilibrium conditions, most especially, temperature, during production and transportation of crude oil could cause destabilization, precipitation, and deposition of wax. This could affect the flow properties of the crude oil including the viscosity, pour point, and may eventually cause total blockage of the flow lines. In this investigation, synthetic waxy crude oil (containing different concentrations of dissolved paraffin wax (5 – 20% wt./wt.) was doped with selected plant seed oils, namely, Castor oil, Moringa oil and Coconut oil (0 – 1.5% v/v). The efficiency of each of the additives to improve the flow properties was compared with those of commercial flow improver, Triethanolamine (TEA). In addition, similar process was modelled and simulated using HYSYS process simulator. It was found that Moringa and Castro oils show good results to improve the pour point. On the other hand, the Coconut oil was observed to have negative effect by increasing the po...

Inventory of spent engine oil continuously increase and indiscriminately disposed of at auto-mechanics garages. Adsorptive separation established to be indispensable in recovery of these hydrocarbons was carried out using Chrysophyllum albidum (African star apple) fruit shell – a renewable resource. In this study, clay pretreated spent engine oil was recovered in a fixed bed adsorption processes and the recovered adsorbate components determined by GC-MS analysis. The results showed African star apple fruit shell adsorbent effective in recovering n-hexane solubilized spent lubricating oil. The study concluded that using the developed African star apple fruit shell adsorbent, an agricultural waste adsorbent in the recovery of waste lubricating oil will enhance greatly the nation’s economy.