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A novel defoamer was synthesized composed of polysiloxane co-modified by fluoroalkyl and polyether. The impacts of the reaction conditions on the conversion of Si-H in polysiloxane were investigated. By response surface analysis based on the above results, the optimal reaction conditions were obtained as follows: ratio of the reactants, 1.25:1; catalyst dosage, 25 µg/g; reaction temperature, 126°C; and the reaction time, 5.6 h. The conversion achieved was 97.7%. The synthesized defoamer was tested by Fourier transform infrared spectroscopy, 1H-NMR, gel-permeation chromatography, etc. The new defoamer has better foam-breaking and -inhibiting performance than the commercial products in the simulated oily system. [ABSTRACT FROM AUTHOR]

Abstract: In an attempt to reduce the production of light cycle oil (LCO), a non-premium fluid catalytic cracking (FCC) product in North America, a large-pore catalyst containing rare-earth-exchanged Y (REY) zeolite, was used to crack two Canadian bitumen-derived crude heavy gas oils (HGOs) hydrotreated to different extents. For comparison, a regular equilibrium FCC catalyst with ultra-stable Y (USY) zeolite and a conventional western Canadian crude HGO were also included in the study. Cracking experiments were conducted in a fixed-bed microactivity test (MAT) reactor at 510 °C, 30 s oil injection time, and varying catalyst-to-oil ratios for different conversions. The results show that pre-cracking of heavy molecules with wide-pore matrix, followed by zeolite cracking, enhanced conversion at the expense of light and heavy cycle oils at a constant catalyst-to-oil ratio, giving improved product selectivities (e.g., higher gasoline and lower dry gas, LCO, and coke yields, in general, at a given conversion). To systematically assess the benefits of employing the specialty catalyst over the regular catalyst in cracking Canadian HGOs, individual product yields were compared at common bases, including constant catalyst-to-oil ratios, conversions, and coke yields for three feeds, and at maximum gasoline yield for one feed. In most cases, the preferred choice of large-pore zeolite-rich catalyst over its counterpart was evident. The observed cracking phenomena were explained based on properties of catalysts and characterization data of feedstocks, including their hydrocarbon type analyses by gas chromatograph with a mass-selective detector (GC-MSD). [Copyright &y& Elsevier]

This study deals with a systematic investigation of the fluid catalytic cracking (FCC) performance of a bitumen-derived virgin heavy gas oil (HGO) in the presence of its counterpart from bitumen-derived synthetic crude oil (SCO). The objective is to determine the amelioration effect on yield and product slate by the addition of the premium SCO HGO. The 343–525 °C cut virgin bitumen HGO was obtained from distillation of a raw Athabasca oil sands bitumen. It was then blended with different amounts of the 343 °C+ fraction of commercial SCO. Four HGO blends were prepared containing 75, 64, 61, and 48 v% of SCO HGO. Each HGO blend, as well as 100% SCO HGO, were catalytically cracked at 500 and 520 °C using a bench-scale Advanced Cracking Evaluation (ACE) unit. The results show acceptable FCC performance of bitumen virgin HGO when an adequate amount of SCO HGO is added. However, the resulting liquid product may need some quality improvement before use. Several observations, including catalyst poisoning by feed nitrogen and the refractory nature of virgin HGO, are evident and help to explain some observed cracking phenomena. [ABSTRACT FROM AUTHOR]

Abstract: A series of cracking tests in a comprehensive study were conducted on separate occasions involving all or parts of 10 Canadian vacuum gas oil (VGO) feeds and a catalyst. VGOs were cracked in fixed- and fluid-bed microactivity test (MAT) units, the Advanced Cracking Evaluation (ACE) unit, and a modified ARCO riser reactor. Several important observations from this study were reported, including the effects of gasoline precursors on the maximum gasoline yields and aromatics in feeds on the conversion levels at which the maximum gasoline yields occurred. Yield profiles were found to be similar in shapes and relative positions between H2S-free dry gas and catalytic coke for all but one of the feeds. Conversion and yield data obtained from the three batch reactors were compared and discussed. At a given conversion, correlations existed among the fixed- and fluid-bed MAT units, and the ACE for each product yield. A method to check the qualities of MAT and riser data was demonstrated by plotting the coke or total gas selectivity versus the gasoline selectivity. [Copyright &y& Elsevier]

Abstract: This study describes the effects of two catalysts, an octane-barrel and a bottoms-cracking catalyst, on the catalytic cracking of 10 oil-sands bitumen-derived feeds in fixed- and fluid-bed microactivity test (MAT) units, an Advanced Cracking Evaluation (ACE) unit, and a continuous riser pilot unit. This is part of a comprehensive study of the cracking behavior of Canadian vacuum gas oils. In general, at an equivalent catalyst/oil ratio, conversions decreased in the order ACE>fixed-bed MAT>fluid-bed MAT among the batch reactors. Between a batch reactor and the continuous riser, there existed a good correlation for a given product yield as well as for a given product quality, at a specific conversion. For the oil-sands-derived vacuum gas oils, the bottoms-cracking catalyst containing rare-earth-exchanged Y zeolite (REY) with a large-pore active matrix was more effective than the catalyst containing the rare-earth-exchanged ultrastable Y (REUSY) and ZSM-5 zeolites with an active matrix. The overall distribution of feed sulfur in cracked products, and the relationship of the sulfur content of feed with that of light cycle oil (LCO), confirmed the findings reported in the literature. [Copyright &y& Elsevier]