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Pilot/ Production Plant for High Viscosity Materials

IP.com Disclosure Number: IPCOM000106936D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 4 page(s) / 141K

Publishing Venue

IBM

Related People

Arnold, AF: AUTHOR [+2]

Abstract

The purpose of this invention is to perform chemical reactions or mixing operations on extremely viscous polymer solutions. In a pilot plant role, it would collect process data. Although its original purpose was polymer processing, ceramic slurries could be another application.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Pilot/ Production Plant for High Viscosity Materials

       The purpose of this invention is to perform chemical
reactions or mixing operations on extremely viscous polymer
solutions.  In a pilot plant role, it would collect process data.
Although its original purpose was polymer processing, ceramic
slurries could be another application.

      High viscosity solutions present two major problems in chemical
processing and mixing.
(1)  Mixing is very difficult, and mass transfer is poor.
(2)  Convective heat transfer is difficult, and heat transfer is
poor.

      These problems cause (i) thermal and (ii) concentration
gradients in the reaction mixtue.  Consequences may be as follows:
(1)  Nonuniform product compositions.
(2)  Unwanted side reations (e.g., due to thermal gradients).
(3)  Wasted reactants (raw materials).
(4)  Safety hazards due to runaway reactions.
(5)  Wide molecular weight distributions (polydispersity).

      The standard practice of using stirred tank reactors is not
very effective.  High impeller speeds do not guarantee adequate
mixing.  The impeller's mechanical action may also shear polymer
chains and change the molecular weight distribution.
KEY FEATURES OF THE PROPOSAL
(1)  The design uses motionless mixers in the role of tubular
reactors.  The tubes are inside a heat-exchanger shell.
      Advantages:
           (1)  The motionless mixer overcomes the mixing problems.
           (2)  The motionless mixer's action is gentler than an
impeller's action.
           (3)  The shell-and-tube heat exchanger set-up allows much
better heat transfer than a batch reactor. The shell may accept water
for cooling or steam for heating.
Brown Fintube Co. offers a "turbulator" tube insert for heat
exchangers.  The advertisement in "Chemical Engineering Progress"
(01/91, p.  86) states, "Applications include processes that heat
viscous products up to several thousand centipoise, those that cannot
tolerate the shear of inline mixers..."
(2)  The design uses screw-type (progressive cavity) pumps to move
the polymer solution. Advantages:
      (1)  Ability to transport high viscosity materials while
delivering low mechanical shearing forces.
      (2)  Long operating life.
(3)  The design can operate in any of the three traditional reactor
modes.
      Advantages:
      (1)  Closed-loop batch.
      (2)  Open loop or plug flow reactor (PFR).
      (3)  Partially open loop or continuous stirred tank reactor
(CSTR).
(4)  Greater amenability to process control and data acquisition than
a batch reactor.
DESCRIPTION

      The figures show the proposed design.
VALVE POSITIONS

      The shell uses jacket cooling water (JCW) or steam, but not
both at the same time.  When steam is flowing, the water valves are
closed, and vice versa.  The four valves with numbe...