David W Fletcher

52981509, Mar 29, 1994

Aug 13, 1992

7/929544

David L. Fletcher - Turnersville NJ
Michael S. Sarli - Haddonfield NJ
Stuart S-S. Shih - Cherry Hill NJ
Kathleen M. Keville - Beaumont TX
Daria N. Lissy - Glen Mills PA

Mobil Oil Corporation - Fairfax VA

C10G 4500

208 89

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurization followed by treatment over an acidic catalyst comprising a zeolite sorbing 10 to 40 mg 3-methylpentane at 90. degree. C. , 90 torr, per gram dry zeolite in the hydrogen form, e. g. , ZSM-22, ZSM-23, or ZSM-35. The treatment over the acidic catalyst in the second step restores the octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product with an octane number comparable to that of the feed naphtha. The use of the specified zeolite provides greater desulfurization, gasoline selectivity, and octane than obtained using ZSM-5.

54136970, May 9, 1995

Jul 15, 1992

7/913326

David L. Fletcher - Turnersville NJ
Michael S. Sarli - Haddonfield NJ
Stuart S. Shih - Cherry Hill NJ

Mobil Oil Corporation - Fairfax VA

C10G 6902

208 89

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurization followed by treatment over an acidic catalyst containing, preferably an intermediate pore size zeolite such as ZSM-5 and a zeolite such as MCM-22. The treatment over the acidic catalyst in the second step restores the octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product with an octane number comparable to that of the feed naphtha. In favorable cases, using feeds of extended end point such as heavy naphthas with 95 percent points above about 380. degree. F. (about 193. degree. C. ), improvements in both product octane and yield relative to the feed may be obtained.

54136989, May 9, 1995

Aug 5, 1992

7/925001

David L. Fletcher - Turnersville NJ
Mohsen N. Harandi - Langhorne PA
Michael S. Sarli - Haddonfield NJ
Stuart S. Shih - Cherry Hill NJ

Mobil Oil Corporation - Fairfax VA

C10G 6902

208 89

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurization followed by treatment in a second step over a a first catalyst zone comprising a large pore size zeolite material and a second catalyst zone comprising an intermediate pore size material. Preferably, the large pore size material is zeolite beta and the intermediate pore size material is ZSM-5. The treatment in the second step restores the octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product with an octane number comparable to that of the feed naphtha. In favorable cases, using feeds of extended end point such as heavy naphthas with 95 percent points above about 380. degree. F. (about 193. degree. C. ), improvements in both product octane and yield relative to the feed may be obtained.

53207424, Jun 14, 1994

Oct 19, 1992

7/963229

David L. Fletcher - Turnersville NJ
Timothy L. Hilbert - Sewell NJ
David A. Pappal - Haddonfield NJ
David W. Rumsey - Plainfield IL
Gerald J. Teitman - Vienna VA

Mobil Oil Corporation - Fairfax VA

C10G 3500
C10G 4500

208 89

A sulfur-containing catalytically cracked naphtha is upgraded to form a low-sulfur gasoline product by a process which retains the octane contribution from the olefinic front end of the naphtha. Initially, the mercaptan sulfur in the front end of the cracked naphtha is converted to higher boiling disulfides by oxidation. The front end, which is then essentially an olefinic, high octane sulfur-free material, may be blended directly into the gasoline pool. The back end, which now contains the original higher boiling sulfur components such as thiophenes, together with the sulfur transferred from the front end as disulfides, is hydrotreated to produce a desulfurized product. This desulfurized product, which has undergone a loss in octane by saturation of olefins, is then treated in a second stage, by contact with a catalyst of acidic functionality, preferably a zeolite such as ZSM-5, under conditions which produce a product in the gasoline boiling range of higher octane value. Because this second product may contain combined organic sulfur, it may be subjected to a final desulfurization to reduce organic sulfur to acceptable levels.

52904270, Mar 1, 1994

Aug 5, 1992

7/925007

David L. Fletcher - Turnersville NJ
Timothy L. Hilbert - Sewell NJ
Michael S. Sarli - Haddonfield NJ
Stuart S. Shih - Cherry Hill NJ

Mobil Oil Corporation - Fairfax VA

C10G 4500

208 89

Low sulfur gasoline is produced from a catalytically cracked, sulfur-containing naphtha by fractionating the naphtha feed into a number of fractions of differing boiling range and hydrodesulfurizing them by by feeding them into a hydrodesulfurization reactor at spaced locations along the length of the reactor in order of descending boiling range, with the highest boiling fraction first. Staged introduction of the feed into the hydrodesulfurization reactor in this way promotes desulfurization of the sulfur-rich, olefin poor back end of the feed while reducing the saturation of the high octane olefins in the olefin-rich, sulfur-poor front end, so preserving octane while achieving the desired desulfurization. The hydrodesulfurization is followed by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5. The treatment over the acidic catalyst in the second step restores octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product with an octane number comparable to that of the feed naphtha.

RE317748, Dec 18, 1984

Sep 15, 1983

6/532347

David L. Fletcher - North Wales PA
Walter O. Stadlin - North Wales PA

Leeds & Northrup Company - North Wales PA

G06F 1520

364483

There is provided a method for measuring a parameter whose value is calculable as an integral with time of a function of at least one variable so as to make possible the use of a microprocessor when measurements of such variables are desired. The variable is sampled periodically at a frequency asynchronous with the wave form which the variable follows and then there is periodically calculated the value of the function by summing the values for the function determined by the samples taken during the time between the calculations, thus determining the desired integral.

42401496, Dec 16, 1980

Feb 16, 1979

6/012632

David L. Fletcher - North Wales PA
Walter O. Stadlin - North Wales PA

Leeds & Northrup Company - North Wales PA

G06F 1520

364483

There is provided a method for measuring a parameter whose value is calculable as an integral with time of a function of at least one variable so as to make possible the use of a microprocessor when measurements of such variables are desired. The variable is sampled periodically at a frequency asynchronous with the wave form which the variable follows and then there is periodically calculated the value of the function by summing the values for the function determined by the samples taken during the time between the calculations, thus determining the desired integral.

53912888, Feb 21, 1995

Jun 10, 1993

8/074572

Nick A. Collins - Medford NJ
Paul P. Durand - Wilmington DE
David L. Fletcher - Turnersville NJ
Mohsen N. Harandi - Langhorne PA
Edward F. Kondis - New Hope PA
Hartley Owen - Belle Mead NJ
Michael S. Sarli - Haddonfield NJ
Stuart S. Shih - Cherry Hill NJ

Mobil Oil Corporation - Fairfax VA

C10G 4500
C10G 6900

208 89

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha and benzene-rich fraction by hydrodesulfurization in a first reaction zone and treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5 in a second reaction zone to reduce the octane loss which takes place as a result of the hydrodesulfurization. The benzene-rich fraction can be cofed to the first reaction zone or the second reaction zone. The benzene-rich fraction is preferably a heart-cut reformate.