U.S. patent application number 12/595410 was filed with the patent office on 2010-03-18 for method for disassembling a spray drying system.
This patent application is currently assigned to GEA Process Engineering Inc.. Invention is credited to Soren Sten Rasmussen, Robert Howard Turok.
Application Number | 20100069701 12/595410 |
Document ID | / |
Family ID | 38814400 |
Filed Date | 2010-03-18 |
United States Patent
Application |
20100069701 |
Kind Code |
A1 |
Turok; Robert Howard ; et
al. |
March 18, 2010 |
METHOD FOR DISASSEMBLING A SPRAY DRYING SYSTEM
Abstract
The present invention relates to a spray drying system provided
with a neutralizing system, which system is intended for use in the
pharmaceutical industry or in other industries, where the product
is e.g. infectious, toxic or highly reactive and constitutes a risk
for the surroundings and/or a health risk to people handling the
product. The spray drying system comprises a spray drying chamber
(1) comprising a drying chamber (1) provided with an atomizer
device (17), followed by units (2, 3) for collecting of product
powder and means (8) for cleaning the exhaust gas, wherein an
atomization device (16) connected to a vessel (13) containing a
neutralizer agent is placed upstream of the drying chamber (1). The
invention also relates to a method which method comprises the
following steps: i) sterilizing the spray drying system if the
process has to be conducted under aseptic conditions, ii)
processing by drying a fluid feed added to a drying chamber (1)
through one or more atomization nozzle(s) (16), iii) neutralizing
comprising adding a neutralizing agent upstream of the drying
chamber (1), iv) cleaning the spray drying system.
Inventors: |
Turok; Robert Howard;
(Columbia, MD) ; Rasmussen; Soren Sten; (Soborg,
DK) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
GEA Process Engineering
Inc.
Columbia
MD
|
Family ID: |
38814400 |
Appl. No.: |
12/595410 |
Filed: |
April 10, 2008 |
PCT Filed: |
April 10, 2008 |
PCT NO: |
PCT/EP2008/054336 |
371 Date: |
October 9, 2009 |
Current U.S.
Class: |
588/313 ;
425/6 |
Current CPC
Class: |
F26B 21/003 20130101;
B01D 1/18 20130101; B01J 2/02 20130101; B01J 2/04 20130101; F26B
3/12 20130101 |
Class at
Publication: |
588/313 ;
425/6 |
International
Class: |
A62D 3/30 20070101
A62D003/30; B28B 17/00 20060101 B28B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 10, 2007 |
DK |
PCT/DK2007/050042 |
Claims
1. Method for processing hazardous substances in a spray drying
system, wherein the method comprises the following steps: i)
sterilizing the spray drying system if the process has to be
conducted under aseptic conditions, ii) processing by drying a
fluid feed added to a drying chamber through one or more
atomization nozzle(s), iii) neutralizing comprising adding a
neutralizing agent upstream of the drying chamber, iv) cleaning the
spray drying system.
2. Method according to claim 1, wherein the neutralizing step iii)
comprises wetting the inner surfaces of the spray drying system
with a neutralizing aerosol.
3. Method according to claim 1, wherein the neutralizing step iii)
comprises dedusting, disinfecting or chemically neutralizing.
4. Method according to claim 2, wherein the neutralizing aerosol
has a mean droplet diameter between 0.1-50 .mu.m.
5. Method according to claim 1, wherein the neutralizing agent in
step iii) is added while drying gas flows at normal design
rates.
6. Spray drying system for processing toxic, highly reactive or
contaminating substances, wherein said system comprises a spray
drying chamber provided with an atomizer device, followed by units
for collecting of product powder and means for cleaning the exhaust
gas, and wherein an atomization device connected to a vessel
containing a neutralizer agent is placed upstream of the drying
chamber.
7. Spray drying system for processing hazardous substances
according to claim 6, wherein the atomization device is located at
the gas inlet for drying gas to the drying chamber after one or
more filters filtering the process gas.
8. Spray drying system for processing hazardous substances
according to claim 6, wherein the atomization device is one of the
following: a two fluid nozzle, a single fluid nozzle or a
venture.
9. Spray drying system for processing hazardous substances
according to claim 6, wherein the atomizer nozzle is connected to a
tank containing neutralizing agent.
10. Spray drying system for processing hazardous substances,
wherein said system comprises a drying chamber, after treatment
equipment placed downstream of the drying chamber and a process gas
heater placed upstream in relation to the drying chamber, wherein
an inlet filter capable of removing microorganisms at a temperature
below 140.degree. C., is placed upstream of the process gas heater,
and wherein the process gas heater is a non-flaking heater.
11. Spray drying system for processing hazardous substances
according to claim 10, wherein the atomizer nozzle is connected to
a tank containing neutralizing agent.
12. Spray drying system for processing hazardous substances
according to claim 10, wherein an atomization device is located
upstream of the drying chamber, which atomization device is
connected to a vessel containing a neutralizer agent.
13. Spray drying system for processing hazardous substances
according to claim 12, wherein the atomization device is located at
the gas inlet for drying gas to the drying chamber.
14. Spray drying system for processing hazardous substances
according to claim 13, wherein the atomization device is located
downstream of one or more filters filtering the process gas.
15. Spray drying system for processing hazardous substances
according to claim 12, wherein the atomization device is one of the
following: a two fluid nozzle, a single fluid nozzle or a venture.
Description
[0001] The present invention relates to a spray drying system
provided with a neutralizing system, which system is intended for
use in the pharmaceutical industry or in other industries, where
the product is e.g. infectious, toxic or highly reactive and
constitutes a risk for the surroundings and/or a health risk to
people handling the product.
[0002] Spray drying has been applied to many applications within
Pharmaceutical and Chemical areas. New applications are arising
with special requirements. One new spray drying application is the
processing of biological substances and potent compounds such as
pharmaceuticals which could be toxic in small amounts. These
biological substances and potent compounds require novel and
different processing technology than traditional spray drying
applications.
[0003] A spray drying system for a pharmaceutical process is
normally of a size where the expected range of process gas flow
rate is between 15-15000 kg/hr.
[0004] Traditional spray dryers have four basic components: one or
more atomizer units, a unit for providing hot gas, a drying chamber
and a particle recovery system. The four basic stages of a spray
drying process therefore comprise: [0005] 1. Atomization: A liquid
feed stock is atomized into droplets via either a nozzle or a
rotary atomizer. Nozzles use pressure or compressed gas to atomize
the feed while a rotary atomizer uses a wheel rotating at high
speed. [0006] 2. Drying: Heated process gas (normally air or
nitrogen) is brought into contact with the atomized feed using a
gas disperser--leading to evaporation. [0007] 3. Particle
formation: As the liquid rapidly evaporates from the droplet, a
particle forms and falls to the bottom of the chamber. [0008] 4.
Recovery: The powder is recovered from the exhaust gases using a
cyclone or bag filter.
[0009] The whole spray drying process generally has a short
processing time in the order of a few seconds or on special
circumstances a longer time. Spray drying can take place in a
single stage or in a multistage dryer.
INVENTION
[0010] Processing a biological or potent compound in a spray dryer
requires containment i.e. the material inside the spray drying
system should not be allowed to get in contact with the environment
or people working with the spray drying system.
[0011] A traditional way to avoid contact with the surroundings is
to use glove box isolators. These isolators are sealed units with a
conditioned air system. To manipulate the processor within the unit
the operator accesses the enclosure through gloved hands. Items
required to be used or removed during processing are accessed
through rapid transport ports.
[0012] If an infectious substance or potent compounds are processed
the processor will be contaminated after the processing is complete
and the spray drying system has to be thoroughly cleaned before the
next batch.
[0013] Small spray drying systems are normally disassembled and
washed.
[0014] Larger spray drying systems can use nozzles that are
inserted for cleaning in place. To clean these larger systems
operators have to remove the atomization nozzle and replace it with
a cleaning technology. This cleaning technology may be a static
spray ball or a mechanically rotating spray nozzle. The nozzles
have to be inserted into ductwork or vessels by removing either
plugs or other equipment i.e. atomization nozzle.
[0015] Before cleaning both the smaller and the larger systems it
is therefore necessary to open the system which put the operators
and the surroundings at risk of being exposed to the processed
substances.
[0016] Therefore the spray drying system should in order to reduce
or preferably remove the risk to operators and surroundings be
prepared for opening by neutralizing or deactivating the fine
powder inside the equipment before the surroundings are exposed to
the content of the spray drying system. The deactivation system
preferably control fugitive dusts by wetting them.
SUMMARY OF THE INVENTION
[0017] The present invention relates to a method for processing
hazardous substances in a spray drying system. The method comprises
the following steps:
i) sterilizing the cleaned spray drying system, this process step
is optionally and is only needed if the process has to take place
under aseptic conditions, ii) processing a feedstock, iii)
neutralizing by adding a neutralizing agent to the system upstream
of the atomization nozzle and iv) cleaning the spray drying
system.
[0018] According to one embodiment of the method the neutralizing
step comprises wetting the inner surfaces of the spray drying
system with a neutralizing aerosol. The aerosol normally has a mean
droplet diameter between 0.1-50 .mu.m.
[0019] According to a second embodiment of the method the
neutralizing step comprises adding a gas to the system.
[0020] According to one embodiment of the method the neutralizing
step comprises dedusting, disinfecting or chemically
neutralizing.
[0021] According to one embodiment of the method the neutralizing
agent in step iii) is added while drying gas flows at normal design
rates i.e. rates and amounts normally used during the drying
process.
[0022] The present invention relates to a spray drying system for
processing toxic, highly reactive or contaminating substances which
system comprises a spray drying chamber comprising a drying chamber
provided with an atomizer device, followed by units for collecting
of product powder and means for cleaning the exhaust gas where an
atomization device connected to a vessel containing a neutralizer
agent is placed before i.e. upstream of the drying chamber.
[0023] According to one embodiment of the system the atomization
device is placed on the gas inlet for drying gas to the drying
chamber (1) after one or more filters filtering the process gas
i.e. the atomization device is placed between the filter(s) and the
drying chamber.
[0024] According to one embodiment of the system the atomization
device (16) is a two fluid nozzle, a single fluid nozzle or a
venture.
[0025] According to one embodiment of the system the atomizer
nozzle is connected to a tank containing neutralizing agent.
[0026] According to one embodiment of the system comprises a drying
chamber, after treatment equipment placed downstream of the drying
chamber and a process gas heater placed upstream in relation to the
drying chamber, where an inlet filter capable of removing
microorganisms at a temperature below 140.degree. C., is placed
upstream of the process gas heater and that the process gas heater
is a non-flaking heater.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The invention is illustrated in the drawings where:
[0028] FIG. 1 shows a spray drying system provided with a nozzle
for atomizing neutralizing agent and a by-pass system.
[0029] FIG. 2 shows a spray drying system provided with a gas
neutralizing system.
[0030] FIG. 3 illustrates the locations of deactivation affected by
front nozzle(s).
[0031] FIG. 4 illustrates the locations of deactivation by
atomization nozzle(s).
[0032] The spray drying system according to the present invention
is designed for biologic or hazardous compound processing. The
deactivation system of the spray drying system will disinfect,
deactivate, neutralize and/or de-dust the internal product contact
surfaces of the spray drying system as a preparation for a thorough
chemical cleaning inside and/or outside the containment isolator or
bio-safety cabinet.
[0033] The sanitization system wets the processor surfaces by
creating a fog or aerosol, i.e. a suspension of liquid particles in
a carrier gas, comprising a neutralizing agent such as a
disinfectant or deactivation agent or an agent for dedusting. The
sanitization systems will not clean the spray drying system of
contaminates, it will only neutralize the compounds which have been
processed in the spray drying system by e.g. disinfecting,
deactivating or de-dusting. The choice of and actual effectiveness
of the neutralizing agent should be determined based on the
biological or chemical characteristics of the solution. It should
also be considered if the spray drying system itself put
restrictions on which agents can be used e.g. disinfectants or
deactivation agents containing disinfecting chlorinated compounds
may damage stainless steel surfaces.
[0034] The spray drying system according to the invention requires
the addition of an atomization device in front i.e. upstream of the
drying chamber (see FIGS. 1 and 2) to create the aerosol and
thereby to disinfect, deactivate or provide dust control of
internal surfaces in the spray dryer system, especially the inner
surfaces of the drying chamber. The atomization device in the spray
drying system providing the treatment can be a two fluid nozzle, a
single fluid nozzle, a venture or another atomizing device. This
atomization device will treat the front "clean" side of the drying
system plus aid in treating down stream components. Treatment
occurs while the process i.e. the drying gas flow at normal design
rates.
[0035] During the processor treatment the product atomization
nozzle i.e. the nozzle(s) through which the liquid feed stock
enters during processing can also provide atomization of the
treatment agent. The product atomization device will participate in
treatment of equipment down stream of the nozzle.
[0036] The treatment agent can blind the exhaust filter during
wetting. Therefore the treatment system may require a by pass
around the exhaust filter. The bypass can include a demister devise
and an exhaust filter.
[0037] A spray drying system converts both aqueous and non aqueous
solutions and suspensions into free flowing powders. The system
will normally use heated filtered nitrogen or air as a drying
gas.
[0038] FIG. 1 shows a spray drying system according to the
invention which system comprises a drying chamber 1, a cyclone 2
separating the powder product from the hot process air and a
product container 3 in which the dry powder product is collected.
The feed liquid is transferred from a feed tank 15 to a mixing
chamber 18 by a pump 11. In the mixing chamber 18 the feed is mixed
with a gas which gas is heated in an atomization gas heater 7 and
afterwards filtered in a filter 6 thereby removing unwanted
impurities from the gas. The atomization gas is normally nitrogen
or air which might have been sterilized. The feed/gas mixture
enters into an atomization nozzle lance mounted in a gas disperser
at the top of the drying chamber 1.
[0039] The feed will be sprayed through one or more atomization
nozzles 17 into the drying chamber 1, where it will be mixed with
hot drying or process gas which hot drying gas has been heated in
the heater 5 and afterwards filtered in the filter 4. In the drying
chamber 1 the feed comes in contact with the heated drying gas this
causes the liquid feed fraction to vaporize and the non-volatile
portion of the feed forms solid particles.
[0040] The vapors and dry particles will be conveyed thru an outlet
duct to the high efficiency cyclone 2. The dried particles are
removed from the process gas in the cyclone 2 and the process gas
exits the cyclone 2 and passes through an exhaust filter 8 placed
in connection with the outlet of the cyclone 2. Afterwards the
exhaust gas can pass thru a not shown police filter before entering
a vent system.
[0041] The product collection containers 3 will also be changed
inside the containment area. The area where the product collection
containers 3 are changed should be isolated from the operating
environment.
[0042] At the completion of the spray dryer product run, the
product container 3 has to be isolated. The operator can manually
switch the feed line to water which causes water or another
cooling/cleaning fluid to flow from a tank 14 to the drying chamber
1 via the pump 11. The inlet temperature of the drying chamber 1 is
lowered as the water feed flows to the atomization nozzle 17. The
water evaporates and thereby cools the drying chamber and other
down stream equipment. When the temperature of the drying chamber 1
reaches 15-60.degree. C. the cooling fluid is turned off and the
spray drying system can be further cooled by passing unheated
drying gas thru the system until the chamber outlet reaches ambient
temperature.
[0043] When the drying chamber 1 outlet has reached ambient
temperature the feed is switched to the deactivation agent where
after fluid is transferred from a tank 13 containing the
deactivation agent to the drying chamber. The deactivation agent
enters the drying chamber 1 either by the feed line by the pump 11
or by the process gas line by a pump 12 or by both connections.
When entering the drying chamber 1 by the process gas line the
liquid deactivation agent enters the gas flow in the line for the
process gas as an aerosol or a fog via one or more fogging nozzles
16. The fogging nozzle 16 can be fed by a peristaltic pump 12.
[0044] The compressed gas in the process gas connection and
gas/liquid suspension exiting the atomization nozzle will spray
disinfectant liquid into the drying chamber 1 and all other down
stream equipment. All surfaces throughout the spray drying system
shall be wetted with agent and this is achieved by controlling the
flow of deactivation agent i.e. the amount of incoming deactivation
agent, and the time the deactivation agent is added to the
equipment. The agent fogging nozzle should only be turned on if the
exhaust filter 8 is in the process gas path.
[0045] The source gas pressure should be monitored. If the process
gas outlet pressure rises this can indicate that the exhaust filter
8 has become wet and should be isolated and bypassed. The valves
around the exhaust filter 8 will switch state and send the exhaust
process gas through a mist eliminator or liquid trap 9 which mist
eliminator 9 removes liquid droplets and then the exhaust process
gas enters into an exit filter 10 before entering the vent
system.
[0046] The deactivation process should be continued until all
internal surfaces of the spray drying system are wet. Then all gas
and liquid flow should be discontinued and the spray drying system
isolated. If necessary the spray drying system could be held until
the deactivation agent has neutralized the system surfaces. In the
case of deposits only the wetted surfaces will be neutralized or
stabilized. The outside surface shall be wetted with disinfected or
deactivation agent.
[0047] The following agents are example of Chemical/disinfectant
Agents which can be used in connection with the deactivation
process according to the invention:
Chlorine bleach (sodium Hypochlorite)
Halogens (Chlorines, Alcide)
Iodophors
[0048] Mulitcycles Providone Iodine chlorhexidine
Alcohols (Acidified)
Phenols Cresols (Centra, Cides 7, Oanicide, CidexPlus)
[0049] Sporocidin Banicide [0050] Glutaqrex [0051] Sterile Biocide
[0052] Wavicide 01 [0053] Wavicide 06 [0054] Synthetics and
chlorophenols [0055] Bitaphene [0056] Expose [0057] Matar [0058]
Beaucoup Synergistic dual phenolics [0059] Pathex
Omni II
Multicide
Baliant
One Stoke Environ
Vestal LpH
Wexide
Sufactants
[0059] [0060] Quaternary [0061] Amoniums
Dyes
Chloroquanidines
[0062] Combination Chloroquanidines with Sulfas
Renalin
Acids
Caustics
CIP 100
CIP 200
CIP 300
[0063] Other cleaning solutions
[0064] FIG. 2 shows an alternative system which is not using liquid
deactivation/disinfectant agents, the spray drying system shown in
FIG. 2 uses deactivation/disinfectant agents in gas form. This
spray drying system will not provide dust control. According to
this system a gas deactivation/disinfectant agent is drawn into the
spray drying system after the drying process has been ended by
using an inductor or another vacuum producing device 18. The vacuum
producing device 18 is turned on at the conclusion of the drying
process after the powder product has been confined in the product
containers 3 when the vacuum producing device 18 is turned on
deactivation/disinfectant agent is drawn into the drying chamber 1
via the valve 16 placed in the process gas connection. As the
deactivation/disinfectant agent is in gas form it will not cause
any wetting of the internal surfaces of the spray drying system.
The deactivating gas should be held in the spray drying system
until the deactivating action has been completed. This gas
introduction could be part of VHP (Vapor phase hydrogen peroxide)
sterilization or sanitization for the enclosure.
[0065] The gas deactivation/disinfectant system includes a place
for a deactivating/disinfecting gas to enter the system and a
device will either draw the deactivating/disinfecting gas into the
spray drying system or push the gas into the spray drying system.
This is normally a part of a treatment to disinfect the processing
environment around the spray drying system, the internals of the
containment enclosure. When the gas disinfectant is used to treat
the enclosure it will be drawn into the processor to treat the
processor.
[0066] The device to create vacuum could be a liquid or gas
eductor, a venture, a vacuum pump, a mechanical compressor or a
steam jet. The disinfectant gas could be pushed into the system
using a centripetal fan, positive displacement blower compressor or
other flow producing device.
[0067] FIG. 3 shows the system of FIG. 1 where the zone exclusively
affected by deactivation agent being added through the fogging
nozzles 16 is marked. This zone covers the "upstream" parts of the
drying chamber i.e. those parts which liquid flowing from the
atomization does reach.
[0068] FIG. 4 shows the system of FIG. 1 where the zone affected by
deactivation agent being added through the atomization nozzles 17
is marked. This zone covers the "downstream" parts of the drying
chamber, cyclone i.e. those parts which liquid flowing from the
atomization does reach. This zone would also be affected by
deactivation agent being added through the fogging nozzles 16 alone
but if deactivation agent is only added through the fogging nozzles
16 that would mean that the neutralizing step would take longer
time compared to a situation where both the fogging and the
atomization nozzles are used in the neutralizing step.
* * * * *