Patent ID: 8324441

Claim:
A process for producing light olefins from pentane comprising: passing a feedstream comprising pentane through a plurality of pentane cracking reactors with each reactor containing a catalyst, comprising a first reactor and a last reactor, in series with heaters disposed between successive reactors, thereby generating an effluent stream comprising light olefins, where the feedstream enters a first reactor and the first reactor generates an intermediate stream, the intermediate stream is heated and passed to a subsequent reactor, and where each subsequent reactor generates an intermediate stream that is heated and passed to the next subsequent reactor, and wherein the last reactor generates a product stream comprising light olefins, wherein the isopentane is more selectively cracked than n-pentane; passing the catalyst sequentially through the reactors, where each reactor has a catalyst inlet and a catalyst outlet, and where the catalyst flows through a catalyst inlet through a reactor and out a catalyst outlet, and where the catalyst flowing out a catalyst outlet is passed to a subsequent reactor catalyst inlet; wherein the reactors comprise a catalyst for cracking the pentane feedstream to light olefins and the reactors are operated at a pressure below 450 kPa; and passing the product stream to a separation unit, thereby generating a light olefin product stream and an n-pentane rich stream; passing the n-pentane rich stream through an isomerization reactor to increase the isopentane content of the n-pentane rich stream; and passing the isomerized n-pentane rich stream to the pentane cracking reactors, thereby generating an increased propylene content in the product stream.