Mark N Bohn

US Patent:

6487859, Dec 3, 2002

Filed:

Jul 31, 2001

Appl. No.:

09/920191

Inventors:

Mark S. Mehos - Boulder CO
Kenneth M. Anselmo - Arvada CO
James B. Moreno - Albuquerque NM
Charles E. Andraka - Albuquerque NM
K. Scott Rawlinson - Albuquerque NM
John Corey - Melrose NY
Mark S. Bohn - Golden CO

Assignee:

Midwest Research Institute - Kansas City MO

International Classification:

B60K 1600

US Classification:

606418, 6064111, 6064115

Abstract:

A hybrid high-temperature solar receiver is provided which comprises a solar heat-pipe-receiver including a front dome having a solar absorber surface for receiving concentrated solar energy, a heat pipe wick, a rear dome, a sidewall joining the front and the rear dome, and a vapor and a return liquid tube connecting to an engine, and a fossil fuel fired combustion system in radial integration with the sidewall for simultaneous operation with the solar heat pipe receiver, the combustion system comprising an air and fuel pre-mixer, an outer cooling jacket for tangentially introducing and cooling the mixture, a recuperator for preheating the mixture, a burner plenum having an inner and an outer wall, a porous cylindrical metal matrix burner firing radially inward facing a sodium vapor sink, the mixture ignited downstream of the matrix forming combustion products, an exhaust plenum, a fossil-fuel heat-input surface having an outer surface covered with a pin-fin array, the combustion products flowing through the array to give up additional heat to the receiver, and an inner surface covered with an extension of the heat-pipe wick, a pin-fin shroud sealed to the burner and exhaust plenums, an end seal, a flue-gas diversion tube and a flue-gas valve for use at off-design conditions to limit the temperature of the pre-heated air and fuel mixture, preventing pre-ignition.

US Patent:

6534552, Mar 18, 2003

Filed:

Jun 1, 2001

Appl. No.:

09/870466

Inventors:

Charles B. Benham - Littleton CO
Mark S. Bohn - Golden CO
Dennis L. Yakobson - Arvada CO

Assignee:

Rentech, Inc. - Denver CO

International Classification:

C07C 2700

US Classification:

518715, 518703, 518704, 518705, 518700

Abstract:

Increased hydrocarbon yields from natural gas and reduced oxygen consumption improvements are obtained by recycling hydrogen to a Fischer-Tropsch reactor, which can have a catalyst exhibiting either a low water gas shift activity such as cobalt, or a high water gas shift activity such as iron. At least a portion of the remaining tail gas, either before or after the hydrogen has been removed, is recycled to the inlet of the synthesis gas production reactor.

US Patent:

6712982, Mar 30, 2004

Filed:

Apr 17, 2003

Appl. No.:

10/417107

Inventors:

Mark S. Bohn - Golden CO
James E. Siebarth - Denver CO

Assignee:

Rentech, Inc. - Denver CO

International Classification:

B01D 2100

US Classification:

210802, 210521, 210522, 518709, 518728

Abstract:

Catalyst particles are separated from the wax in a reactor slurry reactor by feeding a portion of the slurry to a dynamic settler. Heavier catalyst particles settle and are removed as the slurry at the bottom of the settler is recycled back to the reactor. Clarified wax is removed at the top of the settler. A multi-channel baffle prevents turbulence, improving retention of the desired heavier catalyst particles.

US Patent:

6730221, May 4, 2004

Filed:

May 29, 2001

Appl. No.:

09/871148

Inventors:

Mark S. Bohn - Golden CO
James E. Siebarth - Lakewood CO

Assignee:

Rentech, Inc. - Denver CO

International Classification:

B01D 2100

US Classification:

210251, 210521, 210522, 518700, 518705, 518709, 208950, 585902

Abstract:

Catalyst particles are separated from the wax in a reactor slurry reactor by feeding a portion of the slurry to a dynamic settler. Heavier catalyst particles settle and are removed as the slurry at the bottom of the settler is recycled back to the reactor. Clarified wax is removed at the top of the settler. A multi-channel baffle prevents turbulence, improving retention of the desired heavier catalyst particles.

US Patent:

6739136, May 25, 2004

Filed:

Nov 22, 2002

Appl. No.:

10/301982

Inventors:

Mark S. Mehos - Boulder CO
Kenneth M. Anselmo - Arvada CO
James B. Moreno - Albuquerque NM
Charles E. Andraka - Albuquerque NM
K. Scott Rawlinson - Albuquerque NM
John Corey - Melrose NY
Mark S. Bohn - Golden CO

Assignee:

Midwest Research Institute - Kansas City MO

International Classification:

F03G 600

US Classification:

6064115, 606418

Abstract:

A combustion system for a hybrid solar receiver comprises a pre-mixer which combines air and fuel to form an air-fuel mixture. The mixture is introduced tangentially into a cooling jacket. A burner plenum is fluidically connected to the cooling jacket such that the burner plenum and the cooling jacket are arranged in thermal contact with one another. The air-fuel mixture flows through the cooling jacket cooling the burner plenum to reduce pre-ignition of the air-fuel mixture in the burner plenum. A combustion chamber is operatively associated with and open to the burner plenum to receive the air-fuel mixture from the burner plenum. An igniter is operatively positioned in the combustion chamber to combust the air-fuel mixture, releasing heat. A recuperator is operatively associated with the burner plenum and the combustion chamber and pre-heats the air-fuel mixture in the burner plenum with heat from the combustion chamber. A heat-exchanger is operatively associated and in thermal contact with the combustion chamber.

US Patent:

6838487, Jan 4, 2005

Filed:

Dec 4, 2003

Appl. No.:

10/728109

Inventors:

Belma Demirel - Longmont CO, US
Mark S. Bohn - Golden CO, US
Charles B. Benham - Littleton CO, US
James E. Siebarth - Lakewood CO, US
Mark D. Ibsen - Highlands Ranch CO, US

Assignee:

Rentech, Inc. - Denver CO

International Classification:

C07C 2700
B01J 2034

US Classification:

518710, 518709, 502 38, 502 41, 502 45

Abstract:

Solvent extraction is used to remove wax and contaminants from an iron-based Fischer-Tropsch catalyst in a natural circulation continuous-flow system. The wax-free catalyst is then subjected to controlled oxidation to convert the iron to its initial oxidized state, FeO. Reactivation of the oxide catalyst precursor is carried out by addition of synthesis gas.

US Patent:

7108835, Sep 19, 2006

Filed:

Oct 8, 2003

Appl. No.:

10/681823

Inventors:

William H. Hawthorne - Thornton CO, US
Mark D. Ibsen - Highlands Ranch CO, US
Peter S. Pedersen - Boulder CO, US
Mark S. Bohn - Golden CO, US

Assignee:

Rentech, Inc. - Denver CO

International Classification:

F27B 15/14
F27B 15/08
B01J 1/36
F28D 7/00
F28D 11/00

US Classification:

422146, 49147, 49200, 49201, 165 86, 16510416, 16510418, 518728

Abstract:

An arrangement of cooling tubes within a Fischer-Tropsch slurry reactor simplifies removal and reinstallation of cooling tubes for reactor maintenance.

US Patent:

7303731, Dec 4, 2007

Filed:

Dec 7, 2004

Appl. No.:

11/005873

Inventors:

Belma Demirel - Longmont CO, US
Mark S. Bohn - Golden CO, US
Charles B. Benham - Littleton CO, US
James E. Siebarth - Lakewood CO, US
Mark D. Ibsen - Highlands Ranch CO, US

Assignee:

Rentech, Inc. - Los Angeles CA

International Classification:

B01J 8/00
B01J 38/48

US Classification:

422223, 422212, 422213, 422140, 422144, 422145, 422147, 518710, 502 22

Abstract:

Solvent extraction is used to remove wax and contaminants from an iron-based Fischer-Tropsch catalyst in a natural circulation continuous-flow system. The wax-free catalyst is then subjected to controlled oxidation to convert the iron to its initial oxidized state, FeO. Reactivation of the oxide catalyst precursor is carried out by addition of synthesis gas.