Closed-loop thermal servicing of solvent-refining columns
A method of thermally servicing a solvent-refining column comprises: running a closed-loop water-steam system past a top and bottom of a first column, the first column containing at least a solvent and impurities; boiling pressurized water in the closed-loop water-steam system to steam using first heat from the top of the first column; compressing the steam in the closed-loop water-steam system to a higher temperature; and providing second heat to the first column by condensing the steam at the bottom of the first column after compression.
1. A method of thermally servicing a solvent-refining column, the method comprising:
running a closed-loop water-steam system past a top and a bottom of a first column, the first column containing at least a solvent and impurities;
boiling pressurized water in the closed-loop water-steam system to steam by transferring first heat from the top of the first column to the closed-loop water-steam system using a first heat exchanger;
compressing the steam in the closed-loop water-steam system to a higher temperature using a compressor; and
providing second heat to the first column by condensing the steam at the bottom of the first column after compression using a second heat exchanger.
2. The method of claim 1 , wherein water is separated from the solvent and the impurities in a second column, the method further comprising providing third heat to the second column by condensing the steam at a bottom of the second column after compression using a third heat exchanger.
3. The method of claim 2 , further comprising selectively bypassing, at least partially, the bottom of the first or second column with the closed-loop water-steam system using a bypass valve.
4. The method of claim 3 , further comprising applying a heater to the steam after the compression and before the bottom of the second column.
5. The method of claim 1 , further comprising selectively bypassing, at least partially, the bottom of the first column with the closed-loop water-steam system using a bypass valve.
6. The method of claim 1 , further comprising applying a heater to the steam after compression and before the bottom of the first column.
7. The method of claim 1 , wherein the impurities have a boiling point that is less than about 2% lower or higher than a boiling point of the solvent.
8. The method of claim 7 , wherein the solvent is n-methyl pyrrolidone and wherein the impurities are partial oxides of the n-methyl pyrrolidone.
9. The method of claim 1 , further comprising selectively bypassing, at least partially, the top of the first column with the closed-loop water-steam system using a bypass valve.
10. The method of claim 1 , further comprising throttling condensed water in the closed-loop water-steam system, using an expansion valve, before boiling the pressurized water.