Process for the conversion of a paraffinic feedstock

Patent metadata

Field	Value
Publication number	US-9896632-B2
Application number	US-201415032837-A
Country	US
Kind code	B2
Filing date	Oct 30, 2014
Priority date	Oct 31, 2013
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

The disclosure relates to the conversion of a paraffinic feedstock that comprises at least 50 wt % of compounds boiling above 370° c. and which has a paraffin content of at least 60 wt %, an aromatics content of below 1 wt %, a naphthenic content below 2 wt %, a nitrogen content of below 0.1 wt % The process includes:
a) subjecting the paraffinic feedstock to a hydroprocessing step to obtain an at least partially isomerized feedstock; and b) separating the at least partially isomerized feedstock into one or more middle distillate fractions and a first residual fraction. Step (a) is carried out by contacting the paraffinic feedstock with a first catalyst having hydrocracking and hydroisomerizing activity and then with a second catalyst having hydrocracking and hydroisomerizing activity. The second catalyst is more active in hydroisomerization and less active in hydrocracking than the first catalyst.

First claim

That which is claimed is:

1. A process for the conversion of a paraffinic feedstock that comprises at least 50 wt % of compounds boiling above 370° C. and which has a paraffin content of at least 60 wt %, an aromatics content of below 1 wt %, a naphthenic content below 2 wt %, a nitrogen content of below 0.1 wt %, and a sulphur content of below 0.1 wt %, the process comprising:
a) subjecting the paraffinic feedstock to a hydroprocessing step to obtain an at least partially isomerised feedstock;
b) separating the at least partially isomerised feedstock into one or more middle distillate fractions and a first residual fraction,
wherein step a) is carried out by contacting the paraffinic feedstock with a first catalyst having hydrocracking and hydroisomerising activity and then with a second catalyst having hydrocracking and hydroisomerising activity, wherein the second catalyst is a silica-bound, ammonium hexafluorosilicate-treated Pt/ZSM-12 catalyst which is more active in hydroisomerisation and less active in hydrocracking than the first catalyst.

2. A process according to claim 1 , wherein the first catalyst comprises a Group VIII noble metal supported on an amorphous acidic carrier.

3. A process according to claim 1 , further comprising:
c) subjecting at least part of the first residual fraction to vacuum distillation to obtain a distillate base oil fraction and a second residual fraction.

4. A process according to claim 3 , wherein the second residual fraction is recycled to step a).

5. A process according to claim 3 , wherein the process further comprises:
d) subjecting the distillate base oil fraction obtained in step c) to a catalytic dewaxing step to obtain dewaxed base oil fraction.

6. A process according to claim 1 , wherein the paraffinic feedstock is derived from a Fischer Tropsch process.

7. A process according to claim 1 , wherein step a) is carried out in a reactor comprising the first catalyst above the second catalyst in a stacked bed configuration.

8. A process according to claim 1 , wherein the ratio of volume of the first catalyst and volume of the second catalyst is at least 1.0.

9. A process according to claim 8 , wherein ratio of volume of the first catalyst and volume of the second catalyst is in the range of from 1.5 to 10.

10. A process according to claim 2 , wherein the amorphous acidic carrier of the first catalyst is silica-alumina.

11. A process according to claim 1 , wherein the Group VIII noble metal of the first catalyst is platinum.

12. A process according to claim 11 wherein the first catalyst comprises platinum supported on a silica-alumina carrier.

13. A process according to claim 1 wherein step a is performed such that both catalysts are operated at a temperature deviating no more than 20° C. from each other.

Assignees

• Shell Oil Co

Inventors

• Janssen Andries Hendrik
• Kieffer Eduard Philip
• Sammelius Olav

Classifications

• C10G65/12

  including cracking steps and other hydrotreatment steps · CPC title

• C10G45/64

  containing crystalline alumino-silicates, e.g. molecular sieves · CPC title

• C10G69/02 Primary

  plural serial stages only · CPC title

• C10G2/30

  from carbon monoxide with hydrogen · CPC title

• C10G2300/1022

  Fischer-Tropsch products · CPC title