Production method of ethylene and propylene from C5 and C6 alkane

The invention provides a production method of ethylene and propylene. The method is as below: first sending a feedstock rich in C5 and C6 alkane into a reactor containing a dehydrogenation catalyst; conducting an alkane dehydrogenation reaction under the conditions of temperature of 480-700 DEG C, pressure of 0.01-3 MPa, and volume space velocity of 0.1-10 / h; sending the products into a reactor containing a catalytic cracking catalyst; and conducting a catalytic cracking reaction under the conditions of temperature of 450-650 DEG C, pressure of 0.1-3MPa, and volume space velocity of 0.1-10 / h. The C4 and C5 alkane separated from the catalytic cracking products are partially or wholly recycled to a catalytic dehydrogenation unit for recycling. The reaction temperature of the alkene catalytic cracking reaction is lower than the reaction temperature of alkane catalytic cracking reaction; and the method reduces energy consumption, and has high yield of ethylene and propylene. The process of recycling C5 and C6 alkane isolated from the products significantly improves the product yield.