Catalytic conversion process and system with increased propylene production

A process for producing propylene, comprising the steps of:

• step 1:
• providing a starting material comprising olefins having 4+ carbon atoms;
• step 2:
• separating the starting material to obtain a first propylene precursor comprising olefins having 3×2n carbon atoms, wherein n is an integer, a fraction comprising C4 olefin, a fraction comprising C5 olefin, a fraction comprising C7 olefin, and a fraction comprising C8 olefin;
• step 3:
• subjecting a first portion of the fraction comprising C4 olefin to a first oligomerization to produce a first product, and separating the first product to obtain C12 olefin;
• step 4:
• combining the fraction comprising C5 olefin with the fraction comprising C7 olefin, subjecting the combined fractions to a second oligomerization to produce a second product, and separating the second product to obtain C12 olefin;
• step 5:
• combining a second portion of the fraction comprising C4 olefin with the fraction comprising C8 olefin, subjecting the combined fractions to a third oligomerization to produce a third product, and separating the third product to obtain C12 olefin;
• step 6:
• combining the C12 olefin from steps 3, 4, and 5 to produce a second propylene precursor comprising C12 olefin;
• and
• step 7:
• subjecting the first and second propylene precursor to a catalytic cracking reaction to obtain a reaction product comprising propylene.