A mathematical coalescence model in the batch fluidized bed granulator

Huang, Ching Chung; Kono, Hisashi

doi:10.1016/0032-5910(88)80085-8

Cited by 10 publications

(2 citation statements)

References 22 publications

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“…4 The design and operation of such fluidparticle reactors requires an understanding of interparticle adhesive forces, which will depend on the quantity and distribution of the liquid, its viscosity, and its interfacial tension. [4][5][6][7] The trend in developing new coking technologies based on fluidized or moving beds is to minimize the residence time of the vapor products while at the same time ensuring that the solid phase exits the reactor without fouling. An example of the likely behavior of a liquid feed upon introduction into a fluidized bed of particles is illustrated in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…When coking is carried out in fluidized or moving beds, the adhesive forces between the bed particles due to the reacting liquid are of crucial importance . The design and operation of such fluid−particle reactors requires an understanding of interparticle adhesive forces, which will depend on the quantity and distribution of the liquid, its viscosity, and its interfacial tension. − …”

Section: Introductionmentioning

confidence: 99%

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Measurement of Adhesive Forces during Coking of Athabasca Vacuum Residue

Gray

Zhang

McCaffrey

et al. 2003

Ind. Eng. Chem. Res.

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Processes for thermal conversion of vacuum residues in fluidized or moving beds of solid particles require excellent distribution of feed liquid onto the solid particles and free flow of the solids. Forces between the solid particles will be determined by the changing quantity and properties of the liquid material during reaction. This paper presents a unique apparatus for measuring pull-off forces between particles due to reacting liquid films. In the case of 25−30-μm-thick films of Athabasca vacuum residue at 503 °C, the maximum pull-off force occurred after ca. 12 s of reaction and then declined gradually until no force was detected after ca. 24 s of reaction. These data suggest that solid particles coated with vacuum residue would be adhesive for this period of time, while the film of feed material is still liquid and undergoing reaction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measurement of Adhesive Forces during Coking of Athabasca Vacuum Residue

Gray

Zhang

McCaffrey

et al. 2003

Ind. Eng. Chem. Res.

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Fundamentals of bitumen coking processes analogous to granulations: A critical review

Gray

2002

Can J Chem Eng

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estern Canada has enormous resources of bitumen in oilsands deposits, estimated at 4.6 x 10" m3 (NEB, 2000), of which W 12% is recoverable using current technology of either openpit mining or in situ production by steam assisted gravity drainage. This bitumen requires extensive processing in order to produce transportation fuels and petrochemicals. The bitumen contains 50-60 weight % of vacuum residue, i.e., components that cannot be distilled, which must be converted to distillable fractions. The main commercial technologies to accomplish this production are coking the vacuum residue to produce a carbon rich coke solid, distillable liquids and light ends, and hydroconversion with catalyst or additives at high pressure with hydrogen gas (Gray, 1994). Due to a variety of economic and historical factors, coking processes account for the large majority of installed and announced capacity in Canadian upgrading operations. The importance of coking makes further improvements to a process vital to the Canadian oilsands industry.A number of process variables are significant in coking processes, but the two most important are the method used to heat the oil and the residence time of the cracked products in the reactors. The most common process worldwide is delayed coking, where the feed oil is heated in a furnace then introduced into a coke drum. The liquid feed cracks in the coke drum to produce vapour products, light ends and coke. The process operates at low pressure (0-300 kPa) and temperatures of 450-51 0°C (Nelson, 1958). The alternative established commercial coking process is based on a fluid-bed reactor. In fluid coking, the feed is sprayed into a fluidized bed of coke particles (Figure 1; Gray, 1994).The liquid reacts on the surface of the hot particles, again cracking to give distillate products, light gases and coke. The higher reaction temperature (500-540°C) and short residence time of the cracked vapour in the reactor give a higher yield of distillate products relative to coke plus light ends (Nelson, 1958). For example, the yield of coke from fluid coking is approximately 68% of the yield of coke from delayed coking for a range of feed oils. The higher yield of liquid product from fluid coking, for a given feed, is usually attributed to the higher operating temperature and the lower gas-phase residence time of the cracked vapours than in delayed coking.Recent development of thermal cracking processes has sought to enhance the yield of liquid products by reducing the residence time of the cracked vapours still further, and by enhancing the heat transfer 'Author to whom correspondence may be addressed. E-mail address: murray.gray@ualbena.caA number of coking processes use hot particles to heat liquid bitumen or petroleum residue to cause cracking reactions. These particles may be mineral or coke solids. Interactions of these particles, in fluid beds, moving beds and other types of contactors, are governed by the liquid films on the particle surfaces. This paper explores the analogy between granulation and co...

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