I. Introduction

1. Background

The MIP process, developed by Sinopec RIPP, is aimed at maximizing the production of clean gasoline with lower olefin and sulfur content. As a new generation of FCC technology, it can be suitable for conventional FCC revamp or new installation.

2. Process Description

The MIP technology creatively applied a novel Dual Diameter Riser (shown in Fig.1) where recycled catalysts are injected into the second zone.

The MIP process is similar to that of conventional FCC, consisting of reaction-regeneration, fractionation and the gas plant. The feed is injected into the novel Dual Diameter Riser after being dispersed by steam, in which it contacts the hot regenerated catalysts and occurs catalytic cracking reactions. The products are recovered after being separated in fractionation and the gas plant. The spent catalyst with deposited coke, after being stripped by steam, is sent into the regenerator where it is burned off by air, and then recycled to use.

3. Key operating parameters

Main features of MIP in comparison with FCC are listed in Table 1.

Table.1 MIP technical process parameters

II. Technology characteristics

1. Operation flexibility

CThe MIP technology provides operators with flexibility to switch different operation modes based on the demand of products.

2. Feedstock adaptability

The MIP process has been developed into a platform technology, possessing strong feedstock adaptability, which can process VGO, CGO, AR, VR, HVGO, RDS and DAO etc.

3. Main performance

The olefin contained in MIP naphtha can be adjusted from 17v% to 35v%. Compared with the conventional FCC, the MIP process can significantly increase FCC naphtha yield and decrease the production of both dry gas and slurry, while increasing the total liquid yield. The MIP can also reduce sulfur in gasoline by 20 to 40%, and increase isobutane in LPG up to 40%.

The purity of ethylene of the commercial plant is above 99.99v%, and that of propylene is at least 99.9v%, both of which have come up to the standards of high-class product.

4. Running cycle

The on-stream time for MIP units is almost the same as those of conventional FCC units, usually being 3 to 5 years.

III. MIP catalysts

The MIP catalysts have similar physicochemical properties to that of conventional FCC catalysts. The specifications of MIP catalyst are listed in Table 2.

Table.2 MIP Catalyst specifications

IV. Commercial experience

43 MIP units have been installed up to now, and the total processing capacity achieves 66.19 MT/a with the largest one reaching 4.8 MT/a.