Vapor hydrocracking

Reflux overhead vapor recompression, staged crude pre-heat, mechanical vacuum pumps Fluid coking to gasification, turbine power recovery train at the FCC, hydraulic turbine power recovery, membrane hydrogen purification, unit to hydrocracker recycle loop Improved catalysts (reforming), and hydraulic turbine power recovery Process management and integration... 

A species frequently maintains phase equilibrium while it is reacting in one phase. An example is hydrocracking of heavy hydrocarbons in petroleum refining, where H2 from the vapor dissolves into the liquid hydrocarbon phase, where it reacts with large hydrocarbons to crack them into smaller hydrocarbons that have sufficient vapor pressure to evaporate back into the vapor phase. As long as equilibrium of the species between phases is maintained, it is easy to calculate the concentrations in the hquid phase in which reaction occurs. 

The fluid-bed combustion method (2) has been chosen, however, for process development in the regeneration of spent melts from the hydrocracking of coal. In this method, from one to two parts by weight of spent melt is generated for each part of coal fed to the hydrocracking process. The carbonaceous residue, sulfur, and ammonia retained in the melt are burned out with air in a fluidized bed of inert solids. The zinc chloride is simultaneously vaporized, the ash separated from the overhead vapors, and the zinc chloride vapor is condensed as pure liquid for return to the process. 

In most applications, the reaction occurs between a dissolved gas and a liquid-phase reactant in the presence of a solid catalyst. In some cases, the liquid is an inert medium and the reaction takes place between the dissolved gases at the solid surface. These reactors have many diverse applications in catalytic processes and are used extensively in the chemical industry. Trickle-bed reactors have been developed by the petroleum industry for hydrodesulfurization, hydrocracking, and hydrotreating of various petroleum fractions of relatively high boiling point. Under reaction conditions, the hydrocarbon feed is frequently a vapor-liquid mixture that reacts at liquid hourly space velocities (LHSV in volume of fresh feed, as liquid/volume of bed, hr) in the... 

Estimation of gas-liquid mass-transfer rates also requires the knowledge of solubilities of absorbing and/or desorbing species and their variations with temperature (i.e., knowledge of heats of solution). In some reactions, such as hydrocracking, significant evaporation of the liquid occurs. The heat balance in a hydrocracker would thus require an estimation of the heat of vaporization of the oil as a function of temperature and pressure. The data for the solubility, heat of solution, and heat of vaporization for a given reaction system should be obtained experimentally if not available in the literature. 

The trickle-bed reactor can be operated as a partially or completely vapor-phase reactor. It minimizes the energy costs associated with reactant vaporization. Mixed flow conditions at the catalyst surface exist in hydrocracking reactions, hydrogenation of crotonaldehyde and isomerization of cyclopropane. When the temperature rise in a trickle-bed reactor is significant (e.g., hydrodesulfurization and hydrocracking reactions), it can be conveniently controlled by the addition... 

Bifunctional zeolite catalysts such as platinum loaded acid zeolite catalysts are applied in several petroleum refinery operations, designated as hydroconversion processes isomerisation of light n htha, iso-dewaxing and hydrocracking of heavy fractions [4]. Most experimental investigations in academic laboratories are typically performed with pure model components or simple mixtures thereof as feedstock, and using reaction conditions under which the hydrocarbon compounds are in the vapor phase. Industrial hydroconversion processes are mostly run under three phase, or even in some cases under liquid phase conditions and with feedstocks that are extremely complex mixtures of large numbers of different hydrocarbon compounds [4]. 

Chemical stability is an extremely important characteristic of HDV s, but one that has received relatively limited mention in the literature. Most reported studies have dealt with just two sorts of environments The first are those encountered in chemical dealumination processes—strong acids, chelating agents (e.g., EDTA, or soluble silicon sources (e.g., amnionium f luorosilicate). [9,10,11] The second deals with catalytic process environaients—ammonia vapor in hydrocrackers [12,13] or vanadic acid in fluid crackers [14]. Essentially no studies directed towards the specific needs of the catalyst manufacturer are available. 

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