Alternative Technologies for Olefins Production

Flashcards for CHE 528 Crude Oil to Chemicals, Winter 242, Chapter 5: Alternative Technologies for Olefins Production

Olefins Metathesis

A reaction where double bonds are broken and reformed to synthesize propylene from ethylene and butenes.

Lummus OCT (Olefins Conversion Technology)

Using tungsten oxide on silica as the catalyst and operating at a temperature of 300–375°C in a fixed-bed reactor.

Integrating a metathesis unit to a naphtha crackers

Can increases propylene production and The Propylene-to-ethylene yield can be increased from 0.5–0.65:1 kg/kg to as much as 1.1:1 kg/kg.

Advantages of Heterogeneous catalysts

Higher thermal stability, ease of separation from the reaction products and regeneration

Rhenium oxide catalysts

Supported on alumina or silica-alumina, highly active and selective even at low temperatures (20-100°C, easily deactivated and the cost of rhenium compounds is high.

Molybdenum oxide catalysts

Supported on alumina, siliceous material, silica alumina and zeolite alumina composite support, requires comparatively pure feed stream

Tungsten oxide catalysts

Good activity and selectivity for longer period of time, Continuous regeneration without negative effects on catalyst structure and Most attractive for commercial use.

Oxidative Coupling of Methane (OCM)

One of the most promising direct routes to convert methane into ethylene and higher hydrocarbons.

Main Challenges of OCM

Strong exothermicity of OCM reaction, Selectivity control and Low yields of ethylene

Catalytic Dehydrogenation of Light Alkanes

Alkane catalytic dehydrogenation is highly endothermic and equilibrium-limited reaction that is generally carried out at high temperature and low pressure.

Typical catalysts used in Alkane catalytic dehydrogenation

Cr2O3/Al2O3 and Pt/Sn/Al2O3

Types of commercial reactors for alkane dehydrogenation

Adiabatic moving bed reactors (Oleflex) and parallel adiabatic fixed bed reactors (Catofin)

Main Processes that produces the 7 Primary Building Blocks

Steam Cracking, Catalytic Cracking, Catalytic Reforming; Alternative Technologies

7 Primary Building Blocks

Ethylene, Propylene, Butadiene/Butenes, Benzene, Toluene, Xylenes