Gas separation: processes – Liquid contacting – And degasification of a liquid
Reexamination Certificate
1999-08-17
2001-01-16
Smith, Duane S. (Department: 1724)
Gas separation: processes
Liquid contacting
And degasification of a liquid
C095S161000, C095S163000, C095S165000, C095S169000, C095S236000, C096S234000, C096S242000
Reexamination Certificate
active
06174348
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to the use of chemical solvent for the removal of acid gas from a process stream, and the subsequent regeneration of the chemical solvent so that it could be reused for further acid gas removal.
BACKGROUND ART
Many chemical production processes utilize regenerable chemical solvents to remove acid gases from product streams or other process streams. Typically such chemical solvents are regenerated for reuse utilizing steam as a stripping agent and as a source of heat for the endothermic chemical reactions. Such regeneration systems, while effective, are energy intensive.
Accordingly it is an object of this invention to provide a system for regenerating chemical solvents, which have been used to remove acid gas from a process stream, which is more energy efficient than conventionally employed systems for such regeneration.
SUMMARY OF THE INVENTION
The above and other objects, which will become apparent to one skilled in the art upon a reading of this disclosure, are attained by the present invention, one aspect of which is:
A method for regenerating a chemical solvent comprising:
(A) contacting feed gas comprising acid gas with chemical solvent, and passing acid gas from the feed gas into the chemical solvent to produce loaded chemical solvent;
(B) flash vaporizing some of the acid gas from the loaded chemical solvent to produce partially loaded chemical solvent, and heating the partially loaded chemical solvent to produce heated partially loaded chemical solvent;
(C) passing the heated partially loaded chemical solvent in countercurrent mass transfer contact with nitrogen gas and stripping acid gas from the heated partially loaded chemical solvent into the nitrogen gas to produce acidified stripping gas and regenerated chemical solvent;
(D) passing acidified stripping gas in contact with the partially loaded chemical solvent; and
(E) recovering regenerated chemical solvent.
Another aspect of the invention is:
Apparatus for regenerating a chemical solvent comprising:
(A) an absorption column, means for passing feed gas comprising acid gas into the lower portion of the absorption column, and means for passing chemical solvent into the upper portion of the absorption column;
(B) a regeneration column, means for passing fluid from the lower portion of the absorption column to the upper portion of the regeneration column, and means for providing heat to the regeneration column;
(C) a stripping column, means for passing fluid from the lower portion of the regeneration column into the stripping column, and means for providing nitrogen gas into the stripping column;
(D) means for passing fluid from the upper portion of the stripping column into the regeneration column; and
(E) means for recovering regenerated chemical solvent from the lower portion of the stripping column.
As used herein the term “column” means a contacting column or zone wherein liquid and vapor phases are countercurrently contacted to effect separation of a fluid mixture, as for example, by contacting of the vapor and liquid phases on a series of vertically spaced trays or plates mounted within the column and/or on packing elements such as structured or random packing.
As used herein the term “absorption column” means a column wherein suitable chemical solvent selectively absorbs acid gas from a gas mixture.
As used herein the term “stripping column” means a column wherein mass exchange between liquid and gas phases dominates relative to chemical reactions, and results in selective mass transfer of a more volatile component of a downflowing liquid mixture into an upflowing vapor.
As used herein the term “regeneration column” means a column wherein simultaneous liquid phase reactions and mass exchange between liquid and gas phases result in the regeneration of acid gas loaded chemical solvent.
As used herein the term “nitrogen gas” means a fluid comprising at least
95
mole percent nitrogen on a dry basis.
As used herein the terms “upper portion” and “lower portion” mean those sections of a column respectively above and below the mid point of the column.
As used herein the term “indirect heat exchange” means the bringing of two fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
As used herein the term “reboiler” means a device which generates column upflow vapor from column liquid.
As used herein the term “acid gas” means a gas that dissolves in water producing an acidic solution.
As used herein the term “chemical solvent” means a solvent that selectively removes acid from a gaseous mixture by adsorption with reaction with a chemical base present in the solvent.
REFERENCES:
patent: 3252269 (1966-05-01), Woertz
patent: 3594985 (1971-07-01), Ameen
patent: 3824766 (1974-07-01), Valentine et al.
patent: 3880615 (1975-04-01), Grunewald et al.
patent: 3932582 (1976-01-01), Eickmeyer
patent: 3975172 (1976-08-01), Ranke
patent: 4050909 (1977-09-01), Ranke
patent: 4271132 (1981-06-01), Eickmeyer
patent: 4409191 (1983-10-01), Osman
patent: 4430312 (1984-02-01), Eickmeyer
patent: 4551158 (1985-11-01), Wagner et al.
patent: 4609389 (1986-09-01), Karwat
patent: 4702898 (1987-10-01), Grover
patent: 4957515 (1990-09-01), Hegarty
patent: 5066314 (1991-11-01), Leites et al.
patent: 5085675 (1992-02-01), Kriebel et al.
patent: 5145658 (1992-09-01), Chao
patent: 5240476 (1993-08-01), Hegarty
patent: 5435977 (1995-07-01), Chao
Ahmed M. Mushtaq
Drnevich Raymond Francis
Shah Minish Mahendra
Ktorides Stanley
Praxair Technology Inc.
Smith Duane S.
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