Propylene from propane

The dehydrogenation processes used for the production of butadiene from n-butane and -butenes dirring the development of GR-S rubber were modified in the 1990s for the dehydrogenation of propane to propylene. This compensated for the short supply of steam cracked propylene used to produce polypropylene. The new processes can also be used for the dehydrogenation of other paraflins. 

The old Houdry process has been developed by UCI/Lununus to become the Catofin process while Phillips and UOP have introduced their Star and Ole-flex processes. Linde in Germany has also introduced a process. A range of dif- 

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As a general rule difficult or expensive separations should be performed last, since by that time less total material will be involved. Consider Table 4-1, which gives the product mix obtained in a cracking furnace of an ethylene plant and the normal boiling points of the compounds. Suppose it is desired to separate the six groups listed in the table using distillation. The separation of ethylene from ethane and propylene from propane will be the most difficult because they have the smallest boiling-point differences. Therefore, these steps should be performed last. 

Propylene from propane 191 Close-boiling-point problem... 

A simple thermodynamic analysis provides considerably more data to work with. The required task is to separate propylene from propane. On a theoretical basis the ideal work (the minimum availability change) required for this separation is about 400 k BTU s/hr, of which an appreciable fraction is needed to raise the temperature of the products to the final values shown. The available energy (availability, exergy) supplied to this process from the condensing low pressure (20 psig) steam is 18.6 M BTU s/hr. 

Application To produce polymer-grade propylene from propane using the Oleflex process in a propylene production complex. 

An alternative route to the production of propylene from propane would be through oxydehydrogenation ... 

Propylene from propane Reduced reaction temperature, elimination of propane recovery 2,794 20.23 0.057... 

In bench-scale tests, using hoUow-fiber membrane as support and a carrier concentration of 2 M the ethylene permeance was 4.6 X 10 barrer/cm with an ethylene partial pressure of 65 psia, while the selectivity C2H4/C2H6 was about 240. Same tests were carried out for separation of propylene from propane. The selectivity obtained was greater than 100 but this result was confirmed only at bench scale. In fact, in the large pilot system, the selectivity and flux dechned over some weeks due to loss of solvent and carrier and to the necessity of remove hydrogen from the feed gas to prevent reduction of Ag f carrier. Despite the result, this remains the first study on the use of facilitated transport membrane for gas separations on a pilot scale. 

The mechanistic results of this and earlier studies [12] suggest that in addition to producing propylene from propane, the described paraffin activating catalysts could be combined with known olefin oxidation catalysts in a single reactor to produce industrially desirable value added products which are more stable than propylene under the reaction conditions employed such as acrylic acid or acrylonitrile. 

On the other hand, acid sites have been observed on Mo- and P-doped catalysts, specially on those with high MeA/ atomic ratios, and they show a selectivity to olefins lower than the undoped samples. Thus the variation of the selectivity to propylene from propane on metal oxide-doped catalysts could be explained on the basis of the acid-base character of catalysts. 

Propylene demand will grow to the 11-billion lb level by 1973. Propylene from either heavier ethylene feed stocks or European imports will not alleviate the shortage completely. On the other handy it is not expected that price will exceed 3.1 cents/lb. In spite of decreasing propylene availability, refiners will consider release of alkylate stocks at this level. Development of an economic process for direct propylene production is in the future. Dehydrogenation or iodinative partial oxidation processes for propylene from propane are neither commercially proved nor have they been demonstrated to have economic promise. Dehydrogenation in the presence of sulfur may bypass propane dehydrogenation equilibrium limits, and preliminary experimental data are presented. 

It is well known that, in addition to butadiene from butane, the Houdry Catadiene process can produce propylene from propane. This process has been in successful operation to produce butadiene and butene... 

A separation of propylene from propane is achieved by distillation as shown below, where two columns in series are used because a single column would be too tall. The tray numbers refer to equilibrium stages. Determine the column diameters, tray efficiency, number of actual trays, and column heights if perforated trays are used. 

UOP LLC, A Honeywell Co. Propylene Propane Oleflex process produces polymer-grade propylene from propane by catalytic dehydrogenation 11 2010... 

What is the minimum number of theoretical stages required for a Cj splitter to separate propylene from propane if the geometric mean relative volatility between the top and bottom is 1.12, and the desired separation is 99.5% propylene in the distillate and 1% propylene in the bottoms ... 

Several studies concerning the separation of propylene from propane base on faujasite (FAU zeolite) membranes or titanosilicate ETS have been published recently. The olefin/paraffin selectivity of all those materials was comparable to glassy polymers and always below 10. 

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