I. Introduction
1. Background
The CGP process, a new generation of FCC technology developed by Sinopec, is aimed at producing clean gasoline with lower olefin and sulfur content while maximizing propylene yield.
2. Process Description
The CGP technology creatively applied a novel Dual Diameter Riser and proprietary catalysts (Fig.1).The process is similar to that of conventional FCC, consisting of reaction-regeneration, fractionation and the gas plant. After being dispersed by steam, the feed is injected into the novel Dual Diameter Riser and contacts the hot regenerated catalysts where catalytic cracking reactions occur. 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 then sent into the regenerator where it is burned off by air, and then recycled back to the reacting system.
3. Key operating parameters
Table.1 CGP technical process parameters
| Items | Value |
| The 1st zone outlet temp, °C | 510~540 |
| The 2nd zone outlet temp, °C | 500~530 |
| The 1st zone residence time, s | 1.2~1.4 |
| WHSV (the 2nd zone WHSV), h-1 | 15~30 |
| Cat/oil ratio based on the fresh feeds, w/w | 6~8 |
| The dispersed steam based on the total feeds, w% | 4~6 |
II. Technology characteristics
1. Operation flexibility
The CGP technology provides operators with flexibility to switch different operation modes based on the demand of products.
2. Feedstock adaptability
The CGP process has been developed into a platform technology, possessing strong feed adaptability, which can process VGO, CGO, AR, VR, HVGO, RDS and DAO etc.
3. Main performance
The olefin contained in CGP naphtha can be adjusted from 8v% to 30v% while the propylene yield is in the range of 6 ~ 10 %. Compared with the conventional FCC process, the CGP process can significantly increase propylene and LPG yields and decrease dry gas yield, while increasing the total liquid yield. The CGP can also reduce sulfur in the 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 running cycle for CGP units is almost the same as that of conventional FCC units, usually being 3 to 5 years.
III. CGP catalysts
The CGP catalysts have similar physicochemical properties to that of conventional FCC catalysts.
Table.2 CGP catalyst specifications
| Items | Specification values |
| Specific surface area | ≥220 m2/g |
| PV | >0.33 ml/g |
| ABD | 0.75~0.82 g/cm3 |
IV. Commercial experience
24 CGP units have been installed up to now, and the total processing capacity achieves 52.70MT/a with the largest one reaching 4.8MT/a.