Zeeshan Nawaz

Publications (38) View all

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  Article: Green Processing of Coal to Liquid Fuels: Pakistan’s Perspective

  Zeeshan Nawaz, Naveed Ramzan, Saad Nawaz, Shahid Naveed, M. Bilal Khan
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  ABSTRACT: The role of energy supplies in economic prosperity and environmental quality is one of the most important challenges in Pakistan. The continuing upward trend in crude oil prices in the world and heavy reliance on petroleum and its derivatives in daily life makes the economy vulnerable to critical stress. Therefore, the energy security has gained increasing importance. In Pakistan, only the transportation sector consumes one-third of petroleum derived fuels while other consumers include electric power generation and a number of petrochemical products. The use of oxygenates (fuel additives), olefins (petrochemicals), etc. are becoming popular. The recent discoveries of coal reserves and its pronounced scope in the energy sector in the wake of new technologies have led to its green processing and effective utilization. The challenge of efficient utilization and green processing of coal at manageable cost is of interest to researchers. It is through the Coal to Liquid (CTL) technology that coal is converted to valuable liquid hydrocarbons. The two step process, i.e., gasification, followed by its conversion to liquid fuel by Gas-to-Liquid (GTL) technology is a proven strategy, commonly known as Fischer–Tropsch synthesis (FTS) process. Significant improvement of scope in this technology through improved catalysts and process conditions is of interest. Underground Coal Gasification (UCG) is an attractive option for GTL technology for economic gains. Preliminary studies have already been conducted in the country. The prospective use of CTL and GTL fuels technologies in Pakistan has been reviewed in this paper.
  Proceedings of the Pakistan Academy of Sciences 09/2012; 49(3-3):165-172.
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  Article: Synthesis of biodiesel from a model waste oil feedstock using a carbon-based solid acid catalyst: reaction and separation.

  Qing Shu, Zeeshan Nawaz, Jixian Gao, Yuhui Liao, Qiang Zhang, Dezheng Wang, Jinfu Wang
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  ABSTRACT: A solid acid catalyst that can keep high activity and stability is necessary when low cost feedstocks are utilized for biodiesel synthesis because the reaction medium contains a large amount of water. Three solid acid catalysts were prepared by the sulfonation of carbonized vegetable oil asphalt and petroleum asphalt. The structure of these catalysts was characterized by a variety of techniques. A new process that used the coupling of the reaction and separation was employed, which greatly improved the conversion of cottonseed oil (triglyceride) and free fatty acids (FFA) when a model waste oil feedstock was used. The vegetable oil asphalt-based catalyst showed the highest catalytic activity. This was due to the high density and stability of its acid sites, its loose irregular network, its hydrophobicity that prevented the hydration of -OH species, and large pores that provided more acid sites for the reactants.
  Bioresource technology 03/2010; 101(14):5374-84. · 4.25 Impact Factor
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  Article: Synthesis of biodiesel from cottonseed oil and methanol using a carbon-based solid acid catalyst

  Qing Shu, Qiang Zhang, Guanghui Xu, Zeeshan Nawaz, Dezheng Wang, Jinfu Wang
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  ABSTRACT: A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized vegetable oil asphalt and used to catalyze the transesterification of methanol with cottonseed oil. This catalyst was characterized by scanning electron microscopy/energy dispersive spectroscopy, BET surface area and pore size measurement, thermogravimetry analysis and Fourier transform infrared spectroscopy. The sulfonated multi-walled carbon nanotubes (s-MWCNTs) was also prepared and used to catalyze the same transesterification as the asphalt catalyst. The asphalt-based catalyst shows higher activity than the s-MWCNTs for the production of biodiesel, which may be correlated to its high acid site density, its loose irregular network and large pores can provide more acid sites for the reactants. The conversion of cottonseed oil 89.93% was obtained (using the asphalt-based catalyst) when the methanol/cottonseed oil molar ratio was 18.2, reaction temperature at 260 °C, reaction time 3.0 h and catalyst/cottonseed oil mass ratio of 0.2%. Also, it can be re-used. The sulfonated polycyclic aromatic hydrocarbons provide an electron-withdrawing function to keep the acid site stable. The catalyst can substantially reduce energy consumption and waste generation in the production of biodiesel.
  Fuel Processing Technology. 08/2009;
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  Article: Light alkane (mixed feed) selective dehydrogenation using bi-metallic zeolite supported catalyst

  NAWAZ ZEESHAN, Shu Qing, Naveed Shahid, WEI FEI
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  ABSTRACT: Light alkanes are the important intermediates of many refinery processes and their catalytic dehydrogenation gives corresponding alkenes. The aim behind this experimentation is to investigate reaction behavior of mixed alkanes during direct catalytic dehydrogenation and emphasis has been given to enhance propene. Bi-metallic zeolite supported catalyst Pt-Sn/ZSM-5 was prepared by sequentional impregnation method and characterized by BET, EDS and XRD. Direct dehydrogenation reaction is highly endothermic and its conversion is thermodynamically limited. Results showed that the increase in temperature increases the conversion to some extent but there is no overall effect on selectivity of propene. Increase in time-on-stream (TOS) remarkably improves propene selectivity at the expense of lower conversion. The performances of bi-metallic zeolite based catalyst largely affected by coke deposition. The presence of butane and ethane adversely affected propane conversion. Optimum propene selectivity is about 48 %, obtained at 600 oC and time-on-stream 10 h.
  Bulletin of the Chemical Society of Ethiopia. 01/2009;
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  Article: DRASTIC ENHANCEMENT OF PROPENE YIELD FROM 1-HEXENE CATALYTIC CRACKING USING A SHAPE INTENSIFIED MESO-SAPO-34 CATALYST

  NAWAZ ZEESHAN, ZHU JIE, WEI FEI
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  ABSTRACT: A shape intensified Meso-SAPO-34 catalyst was designed and used to improve the yield and selectivity of propene from 1-hexene cracking. The propene was produced with an optimal selectivity of 73.9 wt.% with high feed conversion 98.2 wt.% at 14 per hour WHSV. Robust exponential control of the stereochemistry was observed over the Meso-SAPO-34 shape selective catalyst’s cracking. The influence of the operating parameters on 1-hexene catalytic cracking, such as reaction temperature, time-on-stream effect on product distribution and conversion variations were systematically studied. The yield of propene and conversion rapidly increased with the reaction temperature, until 575oC. Shape intensification and topological integration of SAPO-34 increases the diffusion opportunities for feed, and this phenomenon was found to be responsible for drastic increase in 1-hexene conversion and propene yield. One other reason for this increase is the suppression of surface reactions (isomerization and hydride transfer) owing to better diffusion opportunities. About 55 wt.% propene yield and higher total olefins content was achieved over Meso-SAPO-34.
  Journal of Engineering Science and Technology. 01/2009;