Macro
36
Centrifugal Distillation Still
The Myers Macro-36
Centrifugal Molecular Still is intended for production of high-vacuum
distillation of heat sensitive organic compounds. With over fifty
years of experience in the design and manufacturing of Centrifugal
Molecular Stills, Myers can offer unique qualifications for supplying
the system to our customers requirements.
Basic
Description
The MYERS Macro-36
Centrifugal Molecular Still is designed for throughputs from 100-400
pounds per hour depending upon feed material characteristics.
The material is pumped
into the center of the heated rotating disk housed in a vacuum
chamber.
The feed material is
spread by centrifugal force in a thin film across the face of
the rotor. Film thickness is in the order of 0.010-.100 inches
(.0025 -.025 mm), depending on viscosity, feed rate, etc.
By close temperature
control of heaters, the lighter, lower molecular weight, fraction
of the feed material evaporates and condenses on the internal
water-cooled condenser.
The heavier unevaporated residue slides off the rotor into a collecting
gutter; both fractions flow by gravity to discharge pumps and
are transferred out of the still.
The lower pressure
developed by the vacuum pumps, lowers the boiling point of the
material. This lowered pressure combined with the exponentially
increasing surface area distills material at the most efficient
rate per area of distilling surface, requiring less surface area
per volume of production than other technologies and reducing
the chance of thermal decomposition.
Macro
36 Molecular Distillation Still Diagram |
| 
.. |
.1.
Backing/Roughing Vacuum Pump
... 2.
Diffusion Ejector Pump ( High Vaccuum)
... 3.
Roughing Vacuum Pump ( Degasser Option)
... 4.
Trap (Degasser Option)
... 5.
Chamber Trap
... 6.
Liquid Transfer Pump
... 7.
Check Valve Rotor
... 8.
Inner Heater Rotor
... 9.
Middle Heater Rotor
... 10.
Outer Heater
... 11.
DomedCondenser
... 12.
Rotor
... P
- Vacuum Pressure Gauge |
Major Advantages of the
Macro 36
Major advantages to be expected from the MYERS Macro-36 molecular
still are:
- High product percentage yields
- Elimination of color bodies.
- Elimination of odor fractions.
- Reduction of acid values in ester
distillation.
- Removal of excess reactants.
- Elimination of residual metal
catalysts.
- Minimized thermal hazards (a
necessity for heat sensitive compounds).
The following specifications
cover the complete equipment requirement for a Macro-36 molecular
distillation plant, exclusive of process piping.
Heating - Condensing Surface
The evaporating surface
on the MYERS Macro-36 is that of a 36-inch diameter, 25° cone
that is 7 ft2 (0.66 m2) Because this cone
is rotating at 350 RPM, the average centrifugal unit force spreading
the fluid feed is 40 "g". This gives an effective evaporative
surface, which is greater than that of other types of equipment
of equal actual area.
Performance Specifications
The MYERS Macro-36
Centrifugal Molecular Still is sized to accept up to 400 pounds
per hour (dependent upon feed material characteristics) of degassed
feed material on to the center of a 36-inch diameter heated spinning
rotor within a concentric dished vacuum chamber. At a rotor speed
of 350 R.P.M., the distilland mixture becomes a thin film by centrifugal
force. The resultant film, whose thickness and speed are controlled
by feed rate, radiates to the edge of the rotor.
Three separate electrically controlled
heaters behind the rotor evaporate the lower boiling fraction
of the material. The distillate condenses on the water-cooled
dished head condenser. The unevaporated liquid residue slides
off the rotor into a concentric collecting gutter. Both distillate
and residue gravitate through connecting pipelines to vacuum-
sealed positive liquid gear pumps and discharge from the still
to atmosphere. Drip is also collected and pumped to atmosphere.
Vacuum equipment maintains operating pressures of 1-20 X 10-3
Torr in the still at maximum feed rates. The ultimate pressure
of the Macro-36 molecular still is to be 1 X 10-4 Torr,
clean, dry, and empty.
Operating Objectives
Feed
material should be degassed to remove all but a few percent of
low boiling volatiles. These volatiles may be condensed if desired
or eliminated. A spray degasser will permit maximum reduction
of low boiling volatiles. Incomplete degassing is the major limiting
factor to maximum feed rates to the molecular still. Actual unit
performance can be estimated with a test run on a MYERS Lab-3
Centrifugal Molecular Still.
Still Assembly
The still chamber
is comprised of a 316 stainless steel base plate set at a 45°
angle on a welded steel frame and a top- hinged stainless steel
water-cooled dome. The base plate has a pumping port with a rear
flange that mates to the vacuum pump though a multi-coolant trap
which provides for entrapment separation and protection of pumping
system. Centered on the base plate is the conical 36-inch diameter
stainless steel rotor driven though a water-cooled vacuum feed-through.
Behind the rotor are three independently
wired calrod heater elements, which allows precise temperature
control of rotor area with solid state power controls. They are
insulated from the base plate by baffles. A stainless steel water-cooled
dome condenser is vacuum flanged to the base plate. Two sight
glass viewing ports are provided in the condenser dome. Three
lift hooks permit the customer's hoist to open the still dome
for cleaning and maintenance.
The feed material is pumped from
the de-gasser to the center of the heated spinning rotor. Distillate
condenses upon the inner surface of the water-cooled condenser
dome, and by gravity, passes through the bottom of the base plate
to the distillate liquid gear pump. The unevaporated residue slides
into a stainless steel gutter along the edge of the rotor and
proceeds by gravity to a residue liquid gear pump.
A liquid gear pump is provided for
overflow and drip, which may be combined with the residue or distillate.
The distillate product, drip and residue lines are series 316
stainless steel. Liquid transfer lines are fitted with check valves
that allow continuous feed/discharge to and from still at Atmosphere.
All surfaces in contact with process material are series 316 stainless
steel.
Stainless Steel direct-drive liquid-transfer
pumps with variable speed motors
- Distillate pump
- Residue pump
- Drip pump
- Rotor Feed pump
- Trap drain pump
A digital flow meter is installed
in the feed material process line to accurately measure/adjust
the feed to the still.
Glass flow meters are installed
in residue, distillate, drip and trap drain lines to observe flow
and set gear pump speed.
Valve panel and plumbing provided
for cooling water flow control for components.
Control Center
 The
instrument control panel/distribution center contains the following
controls:
- Main circuit breaker
- Circuit protection for motors,
heaters, pumps, etc.
- Front panel schematic of system
with controls located for ease of operation.
- Lighted switches to show component
status.
- Thermistor vacuum gauges (with
leak detect function) to indicate pressure in the still and
in the foreline.
- Closed loop temperature controllers,
also capable of percent power operation, with solid
state power controls for control of three Rotor heat zones and
digital display of set and actual
temperature of each zone.
- Thermocouples with digital displays
are supplied at the degasser inlet (optional), still inlet,
residue gutter, distillate outlet and residue outlet
Vacuum Pumping System
The
Vacuum Pumping System of the Macro-36 Centrifugal Molecular is
a combination oil booster and mechanical pump. The High vacuum
pump is the Myers KSM-2000 rated at 2500 liters/Minute in the
10-3 Torr pressure range. The Pumping System is supplied
with necessary gasketed vacuum connections to the Macro-36 still.
Installation-Maintenance
Basic reqiurments
- Height required to raise rotor:
8' 6"
- Weight - estimated 3800 pounds
- Electrical - 40 KW at 220V, 60
cycle, 3 phase.
- Water - 13 gallons per minute at
20°C
Myers staff of skilled Engineers are
available to provide installation, maintenance and training of
operators and support personnel.
Options
 Degasser
spray/falling film
- Controls
- Closed loop temperature controllers, also capable of percent
power operation, with solid state power controls for control
zones and digital display of set and actual temperature of each
zone for the degasser
- Two Stainless
Steel direct-drive liquid transfer pumps ( chamber feed and
trap drain) with valuable speed motors adjustable via hand control.
Manually activated on-off via button with indicator status lights
on the control panel.
- Two degass
chambers for parallel operation, with heater bands and removable
thermal covers
- Multi-coolant
trap which provides for entrainment separation and protection
of pumping system.
-
Mechanical
Roughing pump
- Thermistor
vacuum gauge, with leak detect function, to indicate pressure
in the degasser chambers.
- Thermistor
vacuum gauge with lead detect function Line heaters-All interconnecting
process piping can be heat- traced with closed loop\percent
power temperature control Additional condensing area - extra
traps can be added to vacuum line in series with main traps
in chamber or degasser
Line heaters
- All interconnecting process piping can be heat- traced with
closed loop\percent power temperature control
Additional
condensing area - extra traps can be added to vacuum line
in series with main traps in chamber or degasser
Space and Utility Requirements
| 
Myers
Vacuum
