SUMMARY
The Sulzer Chemtech MVGT
TM
tray was tested at Fractionation Research Inc. (FRI) under the Category 1
test program. The results showed that the MVGT tray had the highest useful capacity of any tray tested at
FRI in the Butane System 100 psia.
This Topical Report presents the test results of the Sulzer Chemtech MVGT
TM
tray. The tray was tested
in the 4 ft (1.22 m) diameter high pressure column of the F.R.I. distillation unit with the iso-
butane/normal-butane (iC4/nC4) system at 100 and 165 psia (6.9 and 11.4 bar). The experimental results
of the MVGT tray were compared to those of the standard F.R.I. Type 2 valve tray
(1)
. The capacity,
efficiency and the pressure drop were also compared to experimental results of the sieve tray tested by
F.R.I. in 1987
(2)
, with 0.5 in (12.7 mm) hole diameter and similar percent hole area to the MVGT tray.
For both pressures, the MVGT tray showed substantially higher capacity than the sieve tray and type 2
valve tray. The efficiency of the MVGT tray was about 3 to 4 percent higher than the type 2 valve tray at
low to medium vapor rates, but substantially higher at high vapor rates due to the higher capacity. At total
reflux the pressure drop of the MVGT tray was significantly lower than both the sieve tray and type 2
valve tray.
The comparison of gamma scan results shows that the MVGT tray has less material entrained above the
tray floor than the F.R.I. type 2 valve tray. The MVGT tray has lower tray liquid holdup and downcomer
backup than the type 2 valve tray. There is good agreement between the downcomer backups measured
from the gamma scan and those from the bubblers, except at extreme conditions.
INTRODUCTION
This test was conducted as the 2001 Category 1, F.R.I. paid, proprietary tray test. The MVGT tray was
selected under the tray category. The test was conducted under the proprietary device test procedures
amended at the May, 2001 TAC meeting
(3)
.
The tray was tested for capacity, efficiency and pressure drop using the iC
4
/nC
4
system at 100 and 165
psia (6.9 and 11.4 bar) column pressures. To measure the tray liquid holdup and the downcomer backup,
the tray was gamma scanned and the results were compared to the measurements from bubblers installed
inside downcomers.
DESCRIPTION OF EQUIPMENT
Trays
The Sulzer Chemtech MVGT tray, as shown in
Figure 1, is a fixed valve tray with a truncated
downcomer. The tray deck consisted of MVG (Mini V-Grid) valves to reduce the pressure drop of the
tray deck and lower the froth height on the tray deck. An inlet weir with directional baffles was installed
on the inlet of the tray deck. A sloped truncated downcomer was used in the MVGT tray to maximize
the effective bubbling area. The trays used in these tests were made of 304 stainless steel with a 0.0747
in (1.897 mm) thickness. The downcomers had an area of approximately 17.5% of the column cross
sectional area at top and 10% at the bottom. The bottom plate of the downcomer was 5 in (127 mm)
above the tray deck. A sweptback outlet weir with 2.36 in height (60 mm) was installed for each tray.
The chord length at the downcomer was 39 in (991 mm). The bubbling area of the tray was about 8.93 ft
2
