U.S. patent application number 11/124141 was filed with the patent office on 2005-09-22 for process and apparatus for fluid bed reactions.
This patent application is currently assigned to BP Chemicals Limited. Invention is credited to Becker, Stanley John, Bristow, Timothy Crispin, Clarke, Robert William, Fiorentino, Michele, Newton, David, Reid, Ian Allan Beattle, Williams, Bruce Leo.
Application Number | 20050209101 11/124141 |
Document ID | / |
Family ID | 9893677 |
Filed Date | 2005-09-22 |
United States Patent
Application |
20050209101 |
Kind Code |
A1 |
Becker, Stanley John ; et
al. |
September 22, 2005 |
Process and apparatus for fluid bed reactions
Abstract
A process and apparatus for contacting (a) at least one gaseous
reactant and (b) at least one liquid selected from the group
consisting of reactants, coolants and mixtures thereof in the
presence of a fluidised bed of catalyst, in which the liquid is
introduced into the reactor through at least one inlet located
within the fluidisation zone and the gaseous reactant is introduced
into the reactor through at least one inlet located within the
fluidisation zone adjacent the support means.
Inventors: |
Becker, Stanley John;
(Surrey, GB) ; Bristow, Timothy Crispin;
(Beverley, GB) ; Clarke, Robert William;
(Driffield, GB) ; Fiorentino, Michele; (Aix
Provence, FR) ; Newton, David; (Famham, GB) ;
Reid, Ian Allan Beattle; (Southfields, GB) ;
Williams, Bruce Leo; (Brough, GB) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
BP Chemicals Limited
London
GB
|
Family ID: |
9893677 |
Appl. No.: |
11/124141 |
Filed: |
May 9, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11124141 |
May 9, 2005 |
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09877227 |
Jun 11, 2001 |
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6913734 |
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Current U.S.
Class: |
502/439 |
Current CPC
Class: |
B01J 2219/00263
20130101; B01J 8/1818 20130101; C07C 253/26 20130101; C07C 51/215
20130101; B01J 2208/00884 20130101; C07C 51/252 20130101; B01J 8/22
20130101; C07C 253/24 20130101; B01J 2208/00115 20130101; Y02P
20/582 20151101; C07C 51/215 20130101; C07C 57/145 20130101; C07C
51/215 20130101; C07C 53/08 20130101; C07C 51/252 20130101; C07C
57/145 20130101; C07C 51/252 20130101; C07C 53/08 20130101; C07C
253/24 20130101; C07C 255/08 20130101; C07C 253/26 20130101; C07C
255/08 20130101 |
Class at
Publication: |
502/439 |
International
Class: |
C08G 085/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 14, 2000 |
GB |
0014584.7 |
Claims
1-17. (canceled)
18. Apparatus for fluid bed heterogeneous reactions in which (a) at
least one gaseous reactant and (b) at least one liquid selected
from the group consisting of reactants, coolants and mixtures
thereof, are introduced into a fluidised bed of catalyst, which
apparatus comprises a reactor having: (1) a fluidisation zone for a
fluidised bed of catalyst; (2) means for supporting a fluidised bed
of catalyst within said fluidisation zone; (3) at least one inlet
for introducing at least one gaseous reactant into said reactor;
and (4) at least one inlet for introducing at least one liquid
selected from the group consisting of reactants, coolants and
mixtures thereof into said reactor. in which said at least one
inlet for liquid is located within said fluidisation zone and said
at least one inlet for gaseous reactant is located within said
fluidisation zone adjacent said support means.
19. Apparatus as claimed in claim 18 in which said at least one
inlet for liquid is located in the lower half of the fluidisation
zone.
20. Apparatus as claimed in claim 18 in which said at least one
inlet for liquid is located so that liquid does not impinge on any
solid surfaces within the fluidisation zone.
21. Apparatus as claimed in claim 18 in which said at least one
inlet for gaseous reactant is located at a distance from said
catalyst support means of greater than any potential flame length
when said gaseous reactant comprises molecular oxygen containing
gas.
22. Apparatus as claimed in claim 18 wherein said gaseous reactant
comprises a molecular oxygen-containing gas.
23. Apparatus as claimed in claim 22 wherein one or more second
gaseous reactants are introduced into the reactor.
24. Apparatus as claimed in claim 23 in which said one or more
second reactants are introduced at least in part, separately from
said first gaseous reactant.
25. Apparatus as claimed in claim 23 in which said one or more
second gaseous reactants are introduced as a component of the
fluidising gas.
26. Apparatus as claimed in claim 23 in which said one or more
second gaseous reactants comprises ethane, ethylene or mixtures
thereof.
27. Apparatus as claimed in claim 26 in which said liquid
introduced into said reactor comprises acetic acid and there is
produced vinyl acetate.
28. Apparatus as claimed in claim 26 in which said liquid
introduced into said reactor is selected from the group consisting
of acetate acid, water and mixtures thereof and there is produced
acetic acid by the oxidation of ethylene and/or there is produced
ethylene and/or acetic acid by the oxidation of ethane.
29. A process as claimed in claim 23 in which acrylonitrile is
produced by the reaction of ammonia molecular oxygen-containing gas
and a second reactant selected from the group consisting of
propylene, propane and mixtures thereof.
30. A process as claimed in claim 23 in which maleic anhydride is
produced by the reaction of molecular oxygen-containing gas and a
second reactant selected from the group consisting of butene,
butane and mixtures thereof.
Description
[0001] The present invention relates in general to fluid bed
heterogeneous gas-phase reactions and to apparatus for same.
[0002] Fluid bed reactors and their use in processes involving a
molecular oxygen-containing gas with a solid catalyst for a
heterogeneous gas phase reaction are known, for example from
EP-A-0546677, EP-A-0685449 and EP-A-0847982.
[0003] EP-A-0546677 discloses a process for oxidising ethane to
acetic acid in a fluidized bed reaction zone. In the example
illustrated in EP-A-0546677, ethane is joined with a recycle stream
containing water, CO, CO.sub.2, O.sub.2, ethylene and ethane and
the combined stream is fed to the fluid bed reactor. A molecular
oxygen-containing stream and steam are introduced separately into
the fluid bed reactor. The hot oxidation products exit the top of
the reactor.
[0004] EP-A-0685449 discloses a process for manufacturing vinyl
acetate in a fluid bed reactor comprising feeding ethylene and
acetic acid into the fluid bed reactor through one or more inlets,
feeding an oxygen-containing gas into the fluid bed reactor through
at least one further inlet, co-joining the oxygen-containing gas,
ethylene and acetic acid in the fluid bed reactor while in contact
with a fluid bed catalyst material to enable the ethylene, acetic
acid and oxygen to react to produce vinyl acetate and recovering
the vinyl acetate from the fluid bed reactor. According to
EP-A-0685449, the oxygen may be added in pure form or as an
admixture with inert gas such as nitrogen or carbon dioxide. Since
the oxygen and hydrocarbons are not mixed until they are both
inside the reactor, catalyst is present when they meet and reaction
proceeds immediately, causing the oxygen partial pressure to drop.
Thus, an advantage of feeding an oxygen-containing gas to the
reactor through at least one further inlet in addition to the
ethylene and acetic acid reactants is that it allows significantly
higher levels of oxygen to be safely employed without a high
inventory of flammable gas mixtures.
[0005] EP-A-0847982 discloses a process for the production of vinyl
acetate by reacting at elevated temperature in a fluid bed reactor
ethylene, acetic acid and an oxygen-containing gas in the presence
of a fluid bed catalyst material characterised in that a liquid is
introduced into the fluidised reactor for the purpose of removing
heat therefrom by evaporation of the liquid. According to
EP-A-0847982, the liquid introduced into the fluidised bed reactor
may suitably be a reactant, an inert liquid or a product of the
reaction, or a mixture of any two or more thereof. Thus, at least a
part of the acetic acid reactant may be fed to the fluidised bed
reactor in liquid form. A suitable product is said to be water,
which is formed as a by-product of the reaction of ethylene, acetic
acid and oxygen, because it has a relatively high latent heat of
evaporation. It is stated therein that vinyl acetate product and/or
acetaldehyde by-product may also be recycled and introduced in
liquid form into the fluidised bed reactor.
[0006] According to EP-A-0847982, the liquid may be introduced into
the fluidised-bed reactor by suitably arranged injection means. It
is stated that a single injection means may be used or a plurality
of injection means may be arranged within the fluidised bed
reactor. According to EP-A-0847982, for introducing liquid into the
fluidised catalyst bed, the number of injection means used is that
number which is required to provide sufficient penetration and
dispersion of liquid at each injection means to achieve good
dispersion of liquid across the fluidised catalyst bed. A preferred
injection means is said to be a nozzle or a plurality of nozzles
which include gas-induced atomising nozzles in which a gas is used
to assist in the injection of the liquid, or liquid-only spray-type
nozzles. According to EP-A-0847982, liquid may be introduced with
the ethylene and/or oxygen-containing gas and/or recycle gas fed to
the fluidised bed reactor suitably by bubbling the ethylene and/or
oxygen-containing gas and/or recycle gas through the liquid prior
to its introduction into the reactor. In a further alternative, it
is stated that liquid may be pumped into the area of the grid plate
forming an essential component of a fluid bed reactor where contact
with incoming ethylene and/or oxygen-containing gas and/or recycle
gas would propel the liquid upwards into the fluidised catalyst
bed. In yet a further alternative, it is stated that liquid may be
pumped into the reactor via a sparge bar or bars, optionally with
one or more of the gaseous feeds.
[0007] According to EP-A-0847982, the nozzle or nozzles may be
located in the reactor grid or in the reactor walls above the
grid.
[0008] EP-A-0985655 discloses a fluid bed process for the
production of vinyl acetate which comprises feeding ethylene,
liquid acetic acid and an oxygen-containing gas into a fluid bed
reactor in which the amount of co-promoter is up to 6% by weight of
the catalyst. It is stated therein that the acetic acid is
introduced into the reactor in liquid form, optionally with some
acid in the vapour form and that the liquid acetic acid may be
introduced into the fluid bed reactor by any suitable injection
means, for example a nozzle which may be a gas-induced atomising
nozzle or liquid-only spray-type nozzles. It is also stated therein
that one or more nozzles may be used and that additionally,
recycled acetic acid may be introduced into the reactor either
pre-mixed with the crude acetic acid or using a separate injection
means.
[0009] In the examples illustrated in EP-A-0985655, fresh acetic
acid from storage (1) and recycle acetic acid are pumped together
with some recycle gas (3) to twin fluid nozzle within the fluid bed
(2). The remainder of the recycle gas feed (3), fresh ethylene (4)
and oxygen (5) enter the plenum and through a sintered plate into
the reactor. Fresh oxygen (6) may be fed directly into the fluid
bed. A freeboard section is provided for disengaging the catalyst
(7). The gaseous products exit the reactor through exit (8) through
sintered filter elements (not shown).
[0010] There is a need for an improved process and apparatus for
fluid bed heterogeneous gas-phase reactions in which at least one
gas and at least one liquid are introduced to a fluidised bed of
catalyst.
[0011] Thus, according to one embodiment of the present invention
there is provided a process for contacting (a) at least one gaseous
reactant and (b) at least one liquid selected from the group
consisting of reactants, coolants and mixtures thereof in the
presence of a fluidised bed of catalyst, which process
comprises
[0012] (i) fluidising with a fluidising gas, a bed of fluidisable
catalyst within a fluidisation zone in a reactor, said reactor
having a fluidisation zone for said bed of catalyst and means for
supporting said bed of catalyst within said fluidisation zone;
[0013] (ii) introducing said at least one liquid into said reactor
through at least one inlet located within said fluidisation zone;
and
[0014] (iii) introducing said at least one gaseous reactant into
said reactor through at least one inlet located within said
fluidisation zone adjacent said support means.
[0015] According to another embodiment of the present invention
there is provided apparatus for fluid bed heterogeneous reactions
in which (a) at least one gaseous reactant and (b) at least one
liquid selected from the group consisting of reactants, coolants
and mixtures thereof, are introduced into a fluidised bed of
catalyst, which apparatus comprises a reactor having
[0016] (1) a fluidisation zone for a fluidised bed of catalyst;
[0017] (2) means for supporting a fluidised bed of catalyst within
said fluidisation zone;
[0018] (3) at least one inlet for introducing at least one gaseous
reactant into said reactor; and
[0019] (4) at least one inlet for introducing at least one liquid
selected from the group consisting of reactants, coolants and
mixtures thereof into said reactor,
[0020] in which said at least one inlet for liquid is located
within said fluidisation zone and said at least one inlet for
gaseous reactant is located within said fluidisation zone adjacent
said support means.
[0021] In the process and apparatus of the present invention, the
liquid reactant and/or coolant introduced into the fluidised bed of
catalyst may be introduced at any position relative to the support
within the fluidisation zone because the recirculation of the
fluidised catalyst distributes it throughout the zone. An advantage
of the liquid being distributed by the fluidised catalyst is that
fewer inlets for liquid may be required. The distribution of the
liquid by the fluidised catalyst may be facilitated by a suitable
porosity of the catalyst and/or by use of suitable chemical
reagents.
[0022] In the process and apparatus of the present invention,
introducing the gaseous reactant into the fluidised bed of catalyst
through at least one inlet located within said fluidisation zone
adjacent said support means provides a long contact time between
the gaseous reactant and the fluidised bed of catalyst and also
provides a high concentration of the gaseous reactant through-out
the bed. This is beneficial for reactions where the rate of
reaction is dependent upon the concentration of the gaseous
reactant, such as oxygen in the acetoxylation of ethylene to
produce vinyl acetate. Whilst introducing the gaseous reactant into
a plenum below the catalyst bed support might also provide a long
contact time between the gaseous reactant and the catalyst, this
may be restricted. For example, if the gaseous reactant comprises
molecular oxygen, there is a need to avoid potentially explosive
mixtures and/or large inventories of molecular oxygen-containing
gas within the reactor.
[0023] Suitable fluid bed processes for use in the present
invention include the acetoxylation of olefins, for example the
reaction of ethylene, acetic acid and oxygen to produce vinyl
acetate as described in EP-A-0847982, the contents of which are
hereby incorporated by reference. In this process the gaseous
reactant comprises a molecular oxygen-containing gas which nay be
introduced to the reactor together with the ethylene or preferably
at least in part separately from the ethylene. The fluidising gas
may comprise ethylene and oxygen as fresh feed and as components of
recycled gas. At least part of the acetic acid reactant is
introduced as liquid reactant and/or coolant. Other liquids may be
introduced as coolants. By introducing a molecular oxygen
containing gas through at least one inlet located within the
fluidisation zone adjacent the fluid bed support means, a long
contact time of the oxygen with the catalyst is obtained without
risking explosive mixtures within a plenum of the reactor. Liquid
acetic acid reactant and coolant introduced into fluidised bed of
catalyst in the reactor through at least one inlet located within
the fluidisation zone is absorbed by the catalyst and distributed
around the reactor by the fluidised bed of catalyst. Therefore, the
liquid inlet(s) need not be located at the base of the fluidisation
zone. The acetic acid may be replaced in part by acetic
anhydride.
[0024] Another suitable process for use in the present invention is
the oxidation of ethylene to acetic acid and/or the oxidation of
ethane to ethylene and/or acetic acid in which a liquid selected
from acetic acid, water and mixtures thereof are introduced into
the reactor.
[0025] Yet another suitable process for use in the present
invention is the production of acrylonitrile by the reaction of
propylene, propane or mixtures thereof with ammonia and
oxygen-containing gas in which heat of reaction is removed at least
in part by the introduction of liquid (reactant, coolant or
mixtures thereof).
[0026] Another suitable process for use in the present invention is
the production of maleic anhydride from butene, butane or mixtures
thereof.
[0027] More than one inlet for gaseous reactant may be used in the
present invention. The gaseous reactant for these inlets may be
provided from a common source such as a common end box. Gaseous
reactant and other gases may be introduced additionally to the
reactor by other inlets, for example as components in recycle gases
and/or mixed feed gases. Gaseous reactant and other gases may be
introduced as a component of the fluidising gas, to the reactor
through a plenum below the catalyst support means.
[0028] Suitably, the gaseous reactant may comprise a molecular
oxygen-containing gas. Suitable molecular oxygen-containing gases
for use in the present invention include oxygen gas with minor
amounts of impurities such as argon and nitrogen which each may be
present at a concentration of less than 0.1% by volume. The
concentration of oxygen in the molecular oxygen-containing gas is
suitably in the range 10 to 100%, preferably in the range 50 to
100%, for example a concentration of greater than 99.5% by volume,
suitably a concentration of at least 99.6% by volume.
[0029] Any suitable inlet for the gaseous reactant may be used in
the present invention, in particular recognising the hazards which
may have to be considered with such reactants. Thus, for example,
if the gaseous reactant introduced adjacent the catalyst support
means comprises a molecular oxygen-containing gas, for safety, it
is preferably located at a distance from the catalyst support means
of greater than any potential flame length. The potential flame
length is determined by factors such as the inlet pipe diameter and
inlet gas velocity. The inlets should be positioned and inlet
pressures and velocities selected, so that the molecular
oxygen-containing gas is dispersed and mixed in the region of the
inlet. The inlets should be positioned not too close to the reactor
walls, in case there is a shock wave following a detonation. The
inlets should be positioned so that the molecular oxygen-containing
gas does not impinge directly on surfaces or other structures in
the reactor such as inlets for other reactants.
[0030] The liquid introduced into the reactor may be introduced
into the fluidised bed of catalyst for the purpose of removing heat
therefrom by evaporation of the liquid, as a reactant or as a
combination of these purposes. Introducing liquid into the
fluidised bed of catalyst has that advantage of introducing it
where heat is produced in exothermic reactions. Thus, the liquid
introduced into the fluidised bed of catalyst may suitably be a
reactant, an inert liquid or a product of the reaction, or a
mixture of any two or more thereof. In the acetoxylation of
ethylene with a molecular oxygen containing gas and acetic acid,
for example, the acetic acid reactant may be fed to the fluidised
bed of catalyst in liquid form; a suitable product which may be
introduced into the fluidised bed of catalyst is water, which is
formed for example, as a by-product of the acetoxylation reaction
and has a relatively high latent heat of evaporation; and vinyl
acetate product and/or acetaldehyde by-product may also be recycled
and introduced in liquid form into the fluidised bed of catalyst in
a process for production of vinyl acetate.
[0031] Preferably, the inlet for the liquid is located in the lower
half of the fluidisation zone, thereby increasing the opportunity
for the liquid to be distributed by the catalyst. Preferably, the
inlet for the liquid is positioned such that the liquid does not
impinge on any solid surfaces within the fluidisation zone, such as
the surface of cooling coils located within the fluidisation zone
to remove heat of reaction. Since the liquid introduced into the
reaction zone may have a significant momentum, it may assist is
creating and/or stabilising circulation within the fluidised
bed.
[0032] Additionally, one or more second gaseous reactants may also
be introduced into the reactor together with or preferably at least
in part, separately from the gaseous reactant such as molecular
oxygen containing gas. This second gaseous reactant may be
introduced as a component of the fluidising gas. The fluidising gas
may comprise fresh gaseous reactants and/or recycle gases. The
second gaseous reactant introduced into the reactor may be, for
example (i) ethylene and/or (ii) ethane which may be reacted with
the molecular oxygen-containing gas to produce respectively (i)
acetic acid and/or (ii) ethylene and/or acetic acid. Ethylene may
also be used with molecular oxygen-containing gas and acetic acid
to produce vinyl acetate. Ethylene and/or ethane in these reactions
may be used in substantially pure form or admixed with one or more
of nitrogen, methane, ethane, carbon dioxide and water in the form
of steam or one or more of hydrogen, C.sub.3/C.sub.4 alkenes or
alkanes.
[0033] If oxygen-containing gas is mixed with other gaseous
reactants (as fresh feed and/or as recycle gas) outside of the
reactor, the resultant mixture should have a composition outside
the flammability region.
[0034] The process of the present invention may suitably be
operated at a temperature from 100 to 500.degree. C., preferably
140 to 400.degree. C. The process may suitably be operated at a
pressure of 10 to 3000 kPa gauge (0.1 to 30 barg), preferably 20 to
2500 Pa gauge (0.2 to 25 barg).
[0035] In the fluidisation zone of the reactor, the particles of
the catalyst are maintained in a fluidized state by suitable gas
flow through the bed of catalyst.
[0036] The catalyst may be any suitable fluidisable catalyst. The
catalyst may be a supported catalyst. Suitable catalyst supports
include porous silica, alumina, silica/alumina, titania,
silica/titania, zirconia and mixtures thereof. Preferably, the
support is silica. Suitably, the support may have a pore volume
from 0.2 to 3.5 mL per gram of support, a surface area of 5 to 800
m.sup.2 per gram of support and an apparent bulk density of 0.3 to
5.0 g mL.
[0037] A typical catalyst composition useful in this invention, may
have the following particle size distribution--
1 0 to 20 microns 0-30 wt % 20 to 44 microns 0-60 wt % 44 to 88
microns 10-80 wt % 88 to 106 microns 0-80 wt % >106 microns 0-40
wt % >300 microns 0-5 wt %
[0038] Persons skilled in the art will recognise that support
particles sizes of 44, 88, 106 and 300 microns are arbitrary
measures in that they are based on standard sieve sizes. Particle
sizes and particle size distributions may be measured by an
automated laser device such as a Microtrac X100.
[0039] Suitably, the catalyst has a bulk density of from 0.5 to 5
g/cm.sup.3, preferably 0.5 to 3 g/cm.sup.3, especially 0.5 to 2
g/cm.sup.3.
[0040] Suitable catalysts for use in the present invention include
oxidation, ammoxidation and acetoxylation catalysts.
[0041] A catalyst suitable for use in the production of vinyl
acetate by the acetoxylation of ethylene may comprise a Group VIII
metal, a catalyst promoter and an optional co-promoter. The
catalyst may be prepared by any suitable method, such as that
described in EP-A-0672453. The Group VIII metal is preferably
palladium. The Group VIII metal may be present in a concentration
of greater than 0.2% by weight, preferably greater than 0.5% by
weight based upon total weight of catalyst. The metal concentration
may be as high as 10% by weight. Suitable promoters include gold,
copper, cerium or mixtures thereof. A preferred promoter is gold.
The promoter metal may be present in an amount of from 0.1 to 10%
by weight in the finished catalyst. Suitable co-promoters include
Group I, Group II, lanthanide or transition metals, for example
selected from the group consisting of cadmium, barium, potassium,
sodium, manganese, antimony, lanthanum and mixtures thereof, which
are present in the finished catalyst as salts, e.g. an acetate
salt. The preferred salts are potassium or sodium acetate. The
co-promoter is preferably present in the catalyst composition in a
concentration of 0.1 to 15% by weight of catalyst, more preferably,
from 1 to 5% by weight. When a liquid acetic acid feed is used, the
preferred concentration of co-promoter salt is up to 6% by weight,
especially 2.5 to 5.5%. Where the acid is introduced in the vapour
phase the co-promoter salt is preferably present in a concentration
up to 11 wt %.
[0042] Catalyst suitable for the oxidation of ethane to ethylene
and/or acetic acid and/or for the oxidation of ethylene to acetic
acid are described in EP-A-1043064 and WO 99/51339, the contents of
which are hereby incorporated by reference.
[0043] The invention will now be illustrated by way of example only
and with reference to the drawings in which FIG. 1 represents in
schematic form, a longitudinal cross-section of a fluid bed reactor
according to the present invention.
[0044] Referring to FIG. 1. A reactor (1) for a fluid bed reaction
such as the acetoxylation of ethylene to vinyl acetate contains in
use, a fluidized bed of fluidisable catalyst (2), for example a
palladium/gold catalyst supported on a silica support. The
fluidised bed of catalyst is supported in a fluidisation zone (3)
in the reactor (1) by a suitable support grid (4). The reactor (1)
is provided with at least one inlet pipe (5) for a molecular
oxygen-containing gas which inlet is located within the
fluidisation zone (3) adjacent the support grid (4). The reactor
(1) is also provided with at least one inlet (6) for liquid acetic
acid, which inlet is located within the fluidisation zone. The
fluid bed reactor (1) is also provided with cooling coils (8) and a
supply of fluidising gas comprising recycle gases, ethylene
reactant and optionally oxygen reactant through inlet (7) located
in plenum (10) below the support grid (4). The reactor is provided
with an outlet (9). Cooling coils (8) may be used to heat the
catalyst bed at start-up, being provided with a source of hot
fluid.
[0045] The apparatus of FIG. 1 may be used in the acetoxylation of
ethylene to produce vinyl acetate. In use, ethylene reactant and
recycle gases are passed through inlet (7) to plenum (10) and
thence through support grid (4) fluidise the catalyst bed (2) in
the fluidisation zone (3) of the reactor (1). Liquid acetic acid
reactant, is introduced into the fluidised bed (2) in the
fluidisation zone (3) through inlet (6). A molecular
oxygen-containing gas is introduced into the fluidised catalyst bed
(2) in the fluidisation zone (3) through at least one inlet pipe
(5) in the fluidisation zone adjacent the support grid (4). Heat of
reaction is removed at least in part by the cooling coils (8)
provided with a supply of cooling water and in part by evaporation
of the liquid acetic acid. The gaseous reaction products are
removed from outlet (9).
[0046] In the apparatus and process of the present invention, the
liquid acetic acid introduced into the fluidisation zone is
distributed throughout the zone by the recirculation of the
fluidised catalyst. It may therefore be introduced relatively high
up the fluidised bed of catalyst. The molecular oxygen-containing
gas introduced into the fluidised bed of catalyst through the at
least one inlet located within the fluidisation zone adjacent the
fluidised bed support has a long contact the with the fluidised bed
of catalyst.
[0047] Similar apparatus may be used for other reactions involving
the use of molecular oxygen-containing gas--for example the
oxidation of ethylene to acetic acid and/or the oxidation of ethane
to ethylene and/or acetic acid, the ammoxidation of propylene,
propane or mixtures thereof to produce acrylonitrile and the
oxidation of C4's to maleic anhydride.
* * * * *