Low density mist collector pad

1. A knitted wire mesh mist collector pad having an average density (measured in terms of mass per volume of the knitted wire mesh collector pad) and comprising at least three zones of flattened and crimped wire mesh tube, at least two of said zones having densities (measured in terms of mass per volume of the knitted wire mesh in each of said at least two zones) that are different from one another as a result of comprising meshes of different densities (measured in terms of mass per volume of the knitted wire mesh) and the at least three zones arranged so that a density gradient in the direction of gas flow through the pad varies from low density to high density to low density and comprising:

(a) a first zone of the mist collector pad including one or more stacked layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped twice;

(b) a second zone of the mist collector pad including one or more stacked layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped once;

(c) a third zone of the mist collector pad including one or more stacked layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped twice;

(d) the first, second, and third zones secured in a grid which is used to install the mist collector pad in a process gas stream so that during use of the mist collector pad, the first zone is upstream of the second zone and the second zone is upstream of the third zone; and wherein:

(I) the density of the second zone (measured in terms of mass per volume of the second zone) is greater than the density of the first zone;

(II) the density of the second zone is greater than the density of the third zone; and

(III) the wire meshes of the first, second, and third zones are selected so that during use of the mist collector pad, liquid droplets in a process gas stream land on the wire meshes, coalesce on the meshes, and then run off from the meshes due to gravity.

2. The mist collector pad of claim 1 where the average density of the mist collector pad (measured in terms of mass per volume of the mist collector pad) is 2.9 lb/ft 3 .

3. A process vessel comprising the mist collector of claim 1 .

4. A knitted wire mesh mist collector pad comprising:

(a) a first zone of the knitted wire mesh mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped twice;

(b) a second zone of the knitted wire mesh mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped once and wherein: the density of the second zone (measured in weight per unit volume of the second zone) is greater than the density of the first zone (measured in mass per unit volume of the first zone);

(c) a third zone of the knitted wire mesh mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped twice and wherein: the density (measured in weight per unit volume) of the second zone is greater than the density (measured in mass per unit volume) of the third zone; and

(d) the first, second, and third zones secured in a grid which is used to install the knitted wire mesh mist collector pad in a process gas stream so that during use of the knitted wire mesh mist collector pad, the first zone is upstream of the second zone and the second zone is upstream of the third zone; and

(e) wherein the wire meshes of the first, second, and third zones are selected so that during use of the mist collector pad, liquid droplets in a process gas stream land on the wire meshes, coalesce on the meshes, and then run off from the meshes due to gravity.

5. The knitted wire mesh mist collector pad of claim 4 wherein each of the one or more layers of the first zone is constructed of the same type of knitted wire mesh tube that has been (i) flattened and (ii) crimped twice as each of the one or more layers of the third zone of knitted wire mesh tube that has been (i) flattened and (ii) crimped twice.

6. The knitted wire mesh mist collector pad of claim 4 wherein the first, second, and third zones are contiguous.

7. The knitted wire mesh mist collector pad of claim 4 comprising:

(a) a fourth zone of the knitted wire mesh mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped once and wherein: the density of the fourth zone (measured in weight per unit volume) is greater than the density of the first zone and the density of the fourth zone is greater than the density of the third zone;

(b) the fourth zone is secured in the grid so that during use, the third zone is upstream of the fourth zone; and

(c) wherein the wire mesh of the fourth zone is selected so that during use of the knitted wire mesh mist collector pad, liquid droplets in a process gas stream land on the wire mesh, coalesce on the mesh, and then run off from the mesh due to gravity.

8. The knitted wire mesh mist collector pad of claim 7 wherein each layer of the first zone is the same as each layer of the third zone.

9. The knitted wire mesh mist collector pad of claim 7 wherein each layer of the second zone is the same as each layer of the fourth zone.

10. The knitted wire mesh mist collector pad of claim 9 wherein each layer of the first zone is the same as each layer of the third zone.

11. The knitted wire mesh mist collector pad of claim 7 wherein the first, second, third, and fourth zones are contiguous.

12. A knitted wire mesh mist collector pad comprising:

(a) a first zone of the mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped once;

(b) a second zone of the mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped twice, wherein the density of the second zone is less than the density of the first zone;

(c) a third zone of the mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped once, wherein the density of the second zone is less than the density of the third zone;

(d) the first, second, and third zones held in a grid which is used to install the mist collector pad in a process gas stream so that during use of the mist collector pad, the first zone is upstream of the second zone and the second zone is upstream of the third zone; and

(e) wherein, the wire meshes of the first, second, and third zones are selected so that during use of the mist collector pad, liquid droplets in a process gas stream land on the wire meshes, coalesce on the meshes, and then run off from the meshes due to gravity.

13. The knitted wire mesh mist collector pad of claim 12 wherein each layer of the first zone is the same as each layer of the third zone.

14. The knitted wire mesh mist collector pad of claim 12 wherein the first, second, and third zones are contiguous.

15. The knitted wire mesh mist collector pad of claim 12 comprising:

(a) a fourth zone of the mist collector pad having one or more layers of a knitted wire mesh tube that has been (i) flattened and (ii) crimped twice; and

(b) the fourth zone secured in the grid so that during use, the third zone is upstream of the fourth zone; and wherein:

(I) the density of the fourth zone is less than the density of the first zone;

(II) the density of the fourth zone is less than the density of the third zone; and

(III) the wire mesh of the fourth zone is selected so that during use of the mist collector pad, liquid droplets in a process gas stream land on the wire mesh, coalesce on the mesh, and then run off from the mesh due to gravity.

16. The knitted wire mesh mist collector pad of claim 15 wherein each layer of the first zone is the same as each layer of the third zone.

17. The knitted wire mesh mist collector pad of claim 15 wherein each layer of the second zone is the same as each layer of the fourth zone.

18. The knitted wire mesh mist collector pad of claim 17 wherein each layer of the first zone is the same as each layer of the third zone.

19. The knitted wire mesh mist collector pad of claim 17 wherein the first, second, third, and fourth zones are contiguous.