Production of Olefins

Abstract

A process for converting a hydrocarbon feedstock to provide an effluent containing light olefins, the process comprising passing a hydrocarbon feedstock, the feedstock containing at least one C 1 to C 6 aliphatic hetero compound selected from alcohols, ethers, carbonyl compounds and mixtures thereof and steam in an amount whereby the feedstock contains up to 80 weight % steam, through a reactor containing a crystalline silicate catalyst to produce an effluent including propylene, the crystalline silicate having been subjected to de-alumination by a steaming step and being selected from at least one of an MFI-type crystalline silicate having a silicon/aluminium atomic ratio of from 250 to 500 and an MEL-type crystalline silicate having a silicon/aluminium atomic ratio or from 150 to 800.

1 - 10 . (canceled) 
     
     
         11 . A process for converting a carbon containing feedstock to provide an effluent containing light olefins, the process comprising:
 passing a carbon containing feedstock through a reactor containing a crystalline silicate catalyst to produce an effluent comprising propylene which is recovered from the reactor, wherein the carbon containing feedstock is passed over the crystalline silicate catalyst at a reactor inlet temperature of about 550° C.;   wherein the carbon containing feedstock contains at least one C 1  to C 6  aliphatic hetero compound selected from a group consisting of alcohols, ethers, carbonyl compounds and mixtures thereof, and steam in an amount up to 80 weight % of the carbon containing feedstock; and   wherein the crystalline silicate catalyst is pretreated by subjecting the crystalline silicate catalyst to de-alumination by steaming, and wherein the crystalline silicate catalyst is selected from at least one of an MFI-type crystalline silicate having a silicon/aluminum atomic ratio of from 250 to 500 and an MEL-type crystalline silicate having a silicon/aluminum atomic ratio of from 150 to 800.   
     
     
         12 . The process of  claim 11 , wherein the carbon containing feedstock contains at least one hetero compound selected from the group consisting of methanol, ethanol, dimethyl ether, diethyl ether and mixtures thereof. 
     
     
         13 . The process of  claim 11 , wherein the carbon containing feedstock is passed over the crystalline silicate catalyst at a WHSV of from 0.5 to 30 h −1 , the WHSV being based on the weight of the at least one C 1  to C 6  aliphatic hetero compound in the feedstock. 
     
     
         14 . The process of  claim 11 , wherein the partial pressure of the at least on C 1  to C 6  aliphatic hetero compound, when passed over the crystalline silicate catalyst, is from 20 to 400 kPa. 
     
     
         15 . The process of  claim 11 , wherein the effluent exhibits a propylene/ethylene weight ratio ranging from 2 to 10. 
     
     
         16 . The process of  claim 11 , wherein the effluent exhibits a propylene/ethylene weight ratio ranging from 2 to 5. 
     
     
         17 . The process of  claim 11 , wherein the propylene yield is above 35%. 
     
     
         18 . The process of  claim 17 , wherein the time on stream is about 61 minutes. 
     
     
         19 . The process of  claim 17 , wherein the time on stream is about 123 minutes. 
     
     
         20 . The process of  claim 17 , wherein the time on stream is about 185 minutes.