Plural temperature controls of distillation

Claim 3

The method of claim 1 wherein said first operating variable is the reflux rate to the column.

Claim 4

The method of claim 1 wherein said first operating variable is the overhead product withdrawal rate.

Claim 5

The method of claim 1 wherein the said first operating variable is the heat supply to the reboiler.

Claim 6

The method of claim 1 wherein the said operating first variable is the bottoms product withdrawal rate.

Claim 7

The method of claim 1 wherein the said second operating variable is the reflux rate to the column.

Claim 8

The method of claim 1 wherein the said second operating variable is the overhead product withdrawal rate.

Claim 9

The method of claim 1 wherein the said second operating variable is the heat supply to the reboiler.

Claim 10

The method of claim 1 wherein the said second operating variable is the bottoms product withdrawal rate.

Claim 11

In a one feed-two product multicomponent distillation column having a feed tray located between a plurality of rectifying trays and a plurality of stripping trays and having reflux and reboiling facilities, product quality control means comprising in combination: a. at least one temperature sensing means above said feed tray and between 20-40 percent of the distance between the top rectifying tray and said feed tray; b. at least one temperature sensing means below said feed tray between 20-40 percent of the distance between the bottom stripping tray and said feed tray. c. means for measuring the overhead product rate; d. means for measuring the feed rate; e. means for adding the sensed temperatures of (a) and (b) and thereby to obtain a Split Index characteristic of the overall separation between light and heavy components; f. means for subtracting the sensed temperature of (b) from the sensed temperature of (a) and for adding thereto a correction factor proportional to the ratio of the overhead product rate to the feed rate measured in (c) and (d) respectively, thereby obtaining a Fractionation Index characteristic of the product purities; g. means responsive to the summed temperature of (e) for adjusting a first operating variable of the column; h. means responsive to the corrected temperature difference of (d) for adjusting a second operating variable of the column.

Claim 12

In a one feed-two product multicomponent distillation column having a feed tray located between a plurality of rectifying trays and a plurality of stripping trays and having reflux and reboiling facilities, product quality control means comprising in combination: a. at least one temperature sensing means above said feed tray and between 20-40 percent of the distance between the top rectifying tray and said feed tray; b. at least one temperature sensing means below said feed tray between 20-40 percent of the distance between the bottom stripping tray and said feed tray. c. means for measuring the overhead product rate; d. means for measuring the feed rate; e. means for adding the sensed temperatures of (a) and (b) and thereby to obtain a Split Index characteristic of the overall separation between light and heavy components; f. means for subtracting the sensed temperature of (b) from the sensed temperature of (a) and for adding thereto a correction factor proportional to the ratio of the overhead product rate to the feed rate measured in (c) and (d) respectively, thereby obtaining a Fractionation Index characteristic of the product purities; g. means responsive to the summed temperature of (e) for adjusting a first operating variable of the column; h. means responsive to the corrected temperature difference of (d) for adjusting a second operating variable of the column.

Claim 13

The distillation column of claim 10 wherein the said first operating variable is the reflux rate to the column.

Claim 14

The distillation column of claim 10 wherein the said first operating variable is the overhead product withdrawal rate.

Claim 15

The distillation column of claim 10 wherein the first operating variable is the heat supply to the reboiler.

Claim 16

The distillation column of claim 10 wherein the said first operating variable is the bottoms product withdrawal rate.

Claim 17

The distillation column of claim 10 wherein the said second operating variable is the reflux rate to the column.

Claim 18

The distillation column of claim 10 wherein the said second operating variable is the overhead product withdrawal rate.

Claim 19

The distillation column of claim 10 wherein said second operating variable is the heat supply to the reboiler.

Claim 20

The distillation column of claim 10 wherein said second operating variable is the bottoms product withdrawal rate.

Claim 21

The distillation column of claim 10 further comprising: i. a first analyzer means for measuring the impurity content of said overhead product; j. a second analyzer means for measuring the impurity content of said bottoms product; k. a Split-Index Computer means for determining Split Index by dividing the impurity contents measured by said first and second analyzer means; l. a Fractionation Index Computer means for determining Fractionation Index by adding the impurity content of said overhead product measured in (i) to the impurity content said bottom product measured in (j); m. means responsive to the Split Index computer of (k) for adjusting said first operating variable; n. means response to the Fractionation Index computed in (l) for adjusting said second operating variable.

Claim 22

The method of claim 1 further comprising: g. analyzing for the heavy key component contained in said overhead product; h. analyzing for the light key component contained in said bottoms product; i. dividing the heavy key content obtained in (g) by the light key content obtained in (h) and thereby obtaining a Split Index characteristic of the overall separation in the column; j. controlling a first operating variable of the column according to the Split Index obtained in (i); k. adding the light key content of (h) to the heavy key content of (g) and thereby obtaining a Fractionation Index characteristic of the product purities; l. controlling a second operating variable of the column according to the Fractionation Index obtained in (k).