Simulation & Modeling
Yogeshwar N Thakare; Ajay V Kothari; Saurabh Shinde; Pooja Kadam; Natarajan Venkateswaran; Virendrakumar Gupta
Abstract
MgCl2 supported Ti catalyst is used in commercial propylene polymerization process. Morphology is a key performance determination parameter for polymer resins produced by commercial olefin polymerization process. Higher resin flowability and bulk density (greater than 0.38g/cc) are demonstrated by ‘good’ ...
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MgCl2 supported Ti catalyst is used in commercial propylene polymerization process. Morphology is a key performance determination parameter for polymer resins produced by commercial olefin polymerization process. Higher resin flowability and bulk density (greater than 0.38g/cc) are demonstrated by ‘good’ morphological resins (sphericity close to ‘1’). Polymer resin morphology is controlled by morphology of the catalyst used as well as polymerization conditions. The industrially accepted approaches to control polymer resin morphology are by controlling catalyst morphology through various approaches like pre-polymerization of the catalysts. Morphology of the catalyst is dependent on precursor (support) morphology and process parameters for making the catalyst. In this work, we have developed magnesium alkoxide precursor, a Ziegler-Natta catalyst using the precursor and studied its performance in gas phase propylene polymerization process. Further, morphology of different precursor and catalyst samples is evaluated and correlated it using a “computer vision” based approach. The approach involves modeling the circularity (as an analog of sphericity) of a catalyst and precursor particle. It is observed that the circularity of catalyst particles is lower than that of precursor, due to attrition in the process. It is also reflected in increase in particle size distribution span from 0.83 to 1.32 while synthesis of catalyst from precursor. This approach provides a tool to evaluate and screen the catalysts for using in polymerization.
Olefin synthesis
Salman Beyraghi; Mohammad Rostamizadeh; Reza Alizadeh
Abstract
Methanol dehydration is a high potential route for the production of light olefins (C2-C4). In this study, hierarchical Si-rich [B]-ZSM-5 catalysts (Si/Al= 200) were prepared through one-pot hydrothermal synthesis, including boron as a promoter and ethanol as a low-cost secondary template. N2 adsorptiondesorption, ...
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Methanol dehydration is a high potential route for the production of light olefins (C2-C4). In this study, hierarchical Si-rich [B]-ZSM-5 catalysts (Si/Al= 200) were prepared through one-pot hydrothermal synthesis, including boron as a promoter and ethanol as a low-cost secondary template. N2 adsorptiondesorption, XRD, FE-SEM, and FT-IR techniques were applied to characterize the catalysts. The effect of different amounts of ethanol and different operating conditions was studied on the ZSM-5 catalyst preparation and performance in methanol-to-olefins (MTO) reaction. The results showed that the optimum amount of ethanol (ethanol/TPABr=5) led to the highest crystallinity (91.2%), the highest specific surface area (>400 m2g-1), and total pore volume (0.19 cm3g-1). The best catalytic performance was obtained at temperature of 480°C and methanol hourly space velocity (WHSV) of 7.2 h-1. The optimum catalyst had the highest propylene selectivity (58%) and light olefin selectivity (85%). The results proved the high capability of the new strategy for the efficient and fast development of the MTO catalyst.
Polyolefin degradation
Zaher Tamri; Ali Vaziri Yazdi; Mehdi Nekoomanesh Haghighi; Mehrdad Seifali Abbas-Abadi; Amir Heidarinasab
Abstract
Pyrolysis of high impact polystyrene (HIPS) waste has been investigated under different process parameters, such as temperature, heating rate and types of zeolitic catalysts to produce valuable liquid products. Liquid, gas and coke as products of pyrolysis and aromatic, naphthene, olefin and paraffin ...
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Pyrolysis of high impact polystyrene (HIPS) waste has been investigated under different process parameters, such as temperature, heating rate and types of zeolitic catalysts to produce valuable liquid products. Liquid, gas and coke as products of pyrolysis and aromatic, naphthene, olefin and paraffin as liquid components were obtained and their molecular weight distributions were studied with changing the process parameters in a stirred reactor. Aromatic-rich hydrocarbons within the gasoline range were the main pyrolysis products. Type of zeolitic catalysts, temperature and heating rate had significant effects on the products quality and quantity. Non-isothermal mass losses of high impact polystyrene were measured using a thermo-gravimetric analyzer (TGA) at heating rates of 5, 15, 30, 45 and 90°C min-1 until the furnace wall temperature reached 600°C. The DTG (differential thermal gravimetric) curves showed that heating rate had no obvious effect on the degradation trends in the studied range, and by increasing heating rate, the activation energies were decreased obviously from 222.5 to183.6 kJ mol-1.
