Hydrocracking with steam

Catalytic cracking consists of the reaction of the tars with steam (steam reforming. Reaction [xv]), CO2 (dry reforming. Reaction [xvi]), O2 (partial oxidation. Reaction [xvii]), or H2 (hydrocracking. Reaction [xviii]) (Huber et al., 2006). 

Fixed- or packed-bed reactors refer to two-phase systems in which the reacting fluid flows through a tube filled with stationary catalyst particles or pellets (Smith, 1981). As in the case of ion-exchange and adsorption processes, fixed bed is the most frequently used operation for catalysis (Froment and Bischoff, 1990 Schmidt, 2005). Some examples in the chemical industry are steam reforming, the synthesis of sulfuric acid, ammonia, and methanol, and petroleum refining processes such as catalytic reforming, isomerization, and hydrocracking (Froment and Bischoff, 1990). 

For some widely practiced processes, especially in the petroleum industry, reliable and convenient computerized models are available from a number of vendors or, by license, from proprietary sources. Included are reactor-regenerator of fluid catalytic cracking, hydro-treating, hydrocracking, alkylation with HF or H2SO4, reforming with Pt or Pt-Re catalysts, tubular steam cracking of hydrocarbon fractions, noncatalytic pyrolysis to ethylene, ammonia synthesis, and other processes by suppliers of catalysts. Vendors of some process simulations are listed in the CEP Software Directory (AIChE, 1994). 

With present technology it is entirely possible to process the bulk of the crude oil into petrochemicals, and several approaches to this problem have been considered. In this study we consider the approach in which ethylene is produced by conventional steam cracking and the heavy residual petroleum fractions are converted into steam cracker charge by means of residue hydrocracking through the H-Oil process. 

A high heating value product gas ( 850 Btu/scf, C02-free) can be produced directly from coal-steam reactions using a single-stage reactor in conjunction with a multiple catalyst. The conversion ( 60%) is carried out at 2 atm and 650°C. The multiple catalyst consists of potassium carbonate and a nickel methanation catalyst. The influence of each catalyst on the coal-steam reactions is combined in the integrated system. Potassium carbonate increases the total gas production and rate while the nickel catalyst hydrocracks the evolved liquids and methanates the carbon oxides. 

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