Distillation trays

• US 4,749,528 A
• Filed: 12/15/1986
• Issued: 06/07/1988
• Est. Priority Date: 06/28/1984
• Status: Expired due to Fees

• Current Assignee: BOC Group BV (Linde Plc)
• Original Assignee: BOC Group BV (Linde Plc)
• Inventors: Lavin, John T.
• Primary Examiner(s): Chiesa, Richard L.
• Application Number:
  US06/941,576
• Time in Patent Office: 540 Days
• Field of Search: 261/114.1, 261/114.3, 261/114.5, 202/158
• US Class Current: 261/114.1
• CPC Class Codes: B01D 3/22 with horizontal sieve plates or grids; Construction of sieve plates or grids

Abstract

A distillation tray of the sieve type with a chordal weir or outlet has vapor passages therethrough. The density of vapor passages in the main liquid flow area immediately between the liquid inlet and the liquid outlet of the tray is higher than in the remaining area of the tray so that more vapor flow will be directed into the more active main liquid flow area of the tray, whereby the vapor leaving the tray from the main liquid flow area has substantially the same composition as the vapor leaving the tray from the other area.

Claims

1. A distillation sieve tray in which, in use, there are lower liquid flow rates across some areas and higher liquid flows across other areas, comprising vapour passages formed therethrough, said vapour passages consisting essentially of uncovered perforations having a vertical axis, whereby, in use, the passage of the vapour through said perforations does not impact any horizontal component of velocity to the vapour, an inlet having two side edges and a longitudinal edge for liquid and an outlet having two side edges and a longitudinal edge spaced from said inlet, said inlet longitudinal edge being longer than said outlet longitudinal edge and having wings extending towards the outlet, in which the area immediately between the inlet and outlet is bounded by said inlet and outlet and by two straight lines each one of which extends from one said inlet side edge to the closest one of said outlet side edges and has a first density of vapour passages and the remaining immediately adjacent side or periphery areas of the tray have a second density of vapor passages and wherein said perforations are distributed over essentially the whole liquid-bearing surface of said areas and wherein within each one of the areas, the perforations are uniformly distributed and said first density is greater than said second density, so that, in use, the flow of vapour therethrough more closely matches the flow of liquid from the inlet towards the outlet.

2. A distillation tray as claimed in claim 1, being part-circular in shape and in which the vapour passages are in the form of perforations through the tray surface, and the distribution of the perforations is such that in use the ratio of the flow of liquid to flow of vapour associated with areas having a smaller percentage perforate surface area matches more closely the ratio of the flow of liquid to flow of vapour associated with areas having a larger percentage perforate surface area.

3. A distillation tray as claimed in claim 2, said tray being of the chordal weir or outlet type with the inlet and outlet diametrically opposed.

4. A distillation tray as claimed in claim 3, in which the distribution of perforations is such that Fb is significantly greater than Fa and Vb is significantly greater than Va, but Fa/Va equals Fb/Vb, where Fa is the average flow rate of liquid across said remaining area, Fb is the average flow rate of liquid across the area directly between said inlet and said outlet, Va is the average flow rate and vapour through the passages in said remaining area, and Vb is the average flow rate of vapour through the area directly between said inlet and said outlet.