Reforming is the process of rearranging hydrocarbon molecules into new molecular structures under certain conditions, in the catalytic reforming process, mainly occurs the action of formation of aromatic hydrocarbons through dehydrogenation of naphthenes and cyclodehydrogenation of alkanes etc. At the same time, alkane isomerization and hydrocracking reactions will occur too. In the reforming products are mainly aromatic and iso-alkanes with high octane number and extremely low olefin and sulfur. Therefore, high octane number gasoline blends can be obtained by catalytic reforming, It is also an important means to produce light aromatic such as benzene, toluene and xylene and hydrogen.
Currently, classified according to the catalyst regeneration method, Catalytic reforming process can be generally classified as fixed bed semi-regenerative reforming, cyclic regeneration reforming, catalytic continuous regenerative reforming and low pressure combination bed reforming. Among them the characteristics of fixed bed semi-regenerative reforming process are as follows: When the unit has been in continuous production for a considerable period of time，carbon deposition on the catalyst has reached a certain amount, its activity is greatly reduced, reaction temperature rise, as a result, the liquid yield of the product decreases, the hydrogen yield decreases, and the economic benefit becomes worse.
At this point the device shuts down or the reactor is switched over, the deactivated catalyst was regenerated in situ in the reactor, after the activity of the catalyst was restored, then it moves on to the next production run cycle.
Semi-regenerative reforming has low investment due to installation, low operating cost, it is suitable for different production scale and plays an important role in reforming process.
1, Adaptable raw material
C6-C10 in naphtha
2, Physicochemical properties of catalysts
Item | Quality index |
Appearance | Gray or light yellow striped granules |
Diameter mm | Ф1.4-2.0 |
BET m2/g | >160 |
Bulk density g/mL | 0.5-0.65 |
Dispersity kg/L | 0.55-0.62 |
Pore volumeml/g | >0.45-0.55 |
Compressive strengthN/cm | >40 |
Pt content wt% | 0.20-0.30 |
Re content wt% | 0.3-0.45 |
3 ，Process conditions
Reaction condition Item | Reform |
Temperature，℃ | 490-520 |
Pressure，MPa | 1.4-2.1 |
WSV，h-1 | 1.0-2.0 |
H₂/HC，mol：mol | ≥4：1 |
4，Technique flow chart
5 ，Process characteristics
Semi-regenerative reforming process to continuous reforming，has small investment , operation cost low; although the aromatics yield is lower than that of continuous reforming, the liquid yield is higher.