TrayHeart can calculate nearly all types of trays. Bubble-caps are appreciably more expensive than sieve or valve trays and the relative cost will depend on the material of construction used.
Top View Of Arrangement Of Bubble Caps On A Tray Taken From Fig 6 6 Download Scientific Diagram
24 m No.
. The relative volatility and the liquid viscosity serve as the only input variables in calculating conventional distillation tray efficiencies with the empirical correlation developed by OConnell. Distillation Bubble Cap Tray Design - posted in Chemical Process Simulation. For special materials types or thick.
BUBBLE-CAP The bubble cap is one type of bubbling device. In the Profile mode you can combine them together to calculate and analyze the entire column. The bubble-caps were 3 in diameter with square openings.
Bubble-cap trays have been known to have problems with coking polymer formation or high fouling mixtures. Bubble-Cap Tray Hydraulics this or any other correlation see the teaching assistant U h linear gas velocity through risers fts volumetric vapor flow ratetotal riser area per tray h h h h l s ow hg F HG I b KJ 2 4 where b aeration factor dimensionless. PAGE 4 with bubble caps with an outer cap diameter of 2 inch 3 inch 4 inch or 6 inch.
It is more common than dual flow trays. The valve and bubble cap designs are often protected by patents and thus the performance data are suppliedby the vendors. Tray Calculations 37 i The Selection of Pass Tray 37.
The caps divert the vapour flow below the level of liquid on the tray deck where it is jetted into the liquid either through slots at the bottom of the cap or else between the skirt of the cap and the tray deck. The bubble cap tray has the highest turndown ratio with designs of 81 to 101 ratio being common. Downcomer flooding should be avoided.
Three main types of trays are to be discussed. Figure 125 shows the vapor flow through bubble cap trays sieve trays and valve trays. Bubble Cap Arrangement Figure 3.
Being lighter vapour flows up the column and is forced to pass through the liquid via the openings on each tray. Large if froth is expected also allow space for crawling 12 to 24. The riser and the bubble cap.
The caps possess slots 03 cm wide 15 cm long as shown. Where µ L is the liquid viscosity in mPa-s and α is the relative volatility. Each tray had a diameter of approximately 14 and contained 18 bubble-caps.
Due to the riser in the bubble cap it is the only tray that can be designed to prevent liquid from weeping through the vapor passage. Bubble cap trays work well in high turndown applications because the orifices in the bubble caps are in the form of risers whose top opening is elevated significantly above the tray deck. Sieve or valve trays control weeping by vapor velocity.
Bubble Caps - consist of bell shaped caps fixed to cylindrical risers through which the vapour passes the tray deck. Fluid velocity larger than ascending bubbles minimum width. A full schematic can be found in Appendix C.
This article describes the. Details of the cap plate and bubble caps are presented in Figures 2 and 3. 10 considering overall efficiency 25 Tray spacing.
As the caps are fab-ricated by deep drawing the material thickness is about 1mm. Bubble-cap trays require larger tray spacing than sieve tray design. Due to the riser in the bubble cap it is the only tray that can be designed to prevent liquid from weeping through the vapor passage.
Recently very few new bubble-cap columns are being built due to the expense and marginal benefits. Bubble Cap Trays Sieve Trays Valve Trays Typically the liquid flow between trays is governed by a weir on each tray. Bubble cap tray column Column Diameter.
There it will be seen that the plate contains 27 bubble caps each 59 cm diameter arranged on a 140 cm triangular pitch. The cap is mounted so that there is a space between riser and cap to allow the passage of vapour. Illustration of a bubble cap.
Entrainment is about three times larger than a sieve tray. The weir holds a level of liquid on the tray to form a froth bed where rigorous mass transfer between gas and liquid phases occur. Conventionally we are using Bubble cap trays.
Tray to a depth at least equal to the weir height. Hellow allThis is my first enginnering assignment to suggest modification in tray design. A bubble cap tray has riser or chimney fitted over each hole and a cap that covers the riser.
Sieve or valve trays control weeping by vapor velocity. Gas Flow Path b a c d. Bubble cap trays are almost always used in glycol.
It is made up of two parts. 5 Range of velocities 01-07 ftsec. The bubble cap tray has the highest turndown ratio with designs of 81 to 101 ratio being common.
Such that the bubble caps are covered by liquid. The size of the cap tends to create hydraulic gradient across the deck and a high vapor side pressure drop. Again found in references as a function of U ar g 12 where U.
ChE 4253 - Design I. Different tray-type-specific models for the calculation of pressure drop jetflood systemflood choke-flood entrainment and many other values are available. Trays are tending to replace bubble-cap trays.
Schematic of a bubble cap. The flow depends on the length of the weir and how high the liquid level on the tray is above the weir. Reprinted from Seader 1998 The column design allowed for variation in the feed point but for the purposes of our experiments.
OConnell published a graph showing section efficiencies for bubble cap trays which can be represented by 1. If you are facing any difficulties with the new site and want to access our old site please go to httpsarchivenptelacin. 13 Billion views 37 lakhs YouTube subscribers 2300 unique courses available for self study.
As we know they are costly than sieve or valve trays but the they possese good turndown which is important for usI am not getting from. A weir on the tray ensures that there is always some liquid holdup on the tray and is designed such that the the holdup is at a suitable height eg. The total column height was 145.
How to design and optimize Bubble Cap Trays Part 2 Dr-Ing. Residence time criteria 3-5 sec. The Francis weir equation is one example of how the flow off a tray may be.
Tray design calculations should be performed to ensure that trays at the top and bottom of the section meet the design require-ments. The design of trays depends on the density the rate of vapor and liquid through the tray. 610mm Conclusion The process described above is commonly used for dehydration of natural gas using TEG as dehydrating agent.
DISTILLATIONABSORPTION COLUMN TRAY DESIGN.
