| 摘要 |
The present invention relates to a process to make light olefins from an oxygen-containing, halogenide-containing or sulphur-containing organic feedstock comprising:
contacting said oxygen-containing, halogenide-containing or sulphur-containing organic feedstock in a primary reactor with a catalyst made of a metalloaluminophosphate (MeAPO) molecular sieve with lamellar crystal morphology at conditions effective to convert at least a portion of the feedstock to form a first reactor effluent comprising light olefins and a heavy hydrocarbon fraction;
separating said light olefins from said heavy hydrocarbon fraction;
contacting said heavy hydrocarbon fraction in a second reactor at conditions effective to convert at least a portion of said heavy hydrocarbon fraction to light olefins;
wherein said MeAPO either has an empirical chemical composition on an anhydrous basis, after synthesis and calcination, expressed by the formula
H x Me y ,Al z P k O 2 in which,
y+z+k=1
x<=y
y has a value ranging from 0.0008 to 0.4 and advantageously from 0.005 to 0.18
z has a value ranging from 0.25 to 0.67 and advantageously from 0.38 to 0.55
k has a value ranging from 0.2 to 0.67 and advantageously from 0.36 to 0.54
said molecular sieve having predominantly a plate crystal morphology in which the width (W) and the thickness (T) are such as:
W/T is >= 10 and advantageously ranges from 10 to 100, or
wherein said MeAPO has been prepared by a method comprising:
a) forming a reaction mixture containing a texture influencing agent (TIA), an organic templating agent (TEMP), at least a reactive inorganic source of MeO 2 insoluble in the TIA, reactive sources of Al 2 O 3 and P 2 O 5 ,
b) crystallizing the above reaction mixture thus formed until crystals of the metalloaluminophosphate are formed,
c) recovering a solid reaction product,
d) washing it with water to remove the TIA and
e) calcinating it to remove the organic template. |
