U.S. patent application number 15/300881 was filed with the patent office on 2017-01-26 for system comprising a decomposition unit for use on board of a vehicle.
This patent application is currently assigned to Plastic Omnium Advanced Innovation and Research. The applicant listed for this patent is PLASTIC OMNIUM ADVANCED INNOVATION AND RESEARCH. Invention is credited to Francois DOUGNIER, Beatriz MONGE-BONINI, Jules-Joseph VAN SCHAFTINGEN.
Application Number | 20170022866 15/300881 |
Document ID | / |
Family ID | 50424081 |
Filed Date | 2017-01-26 |
United States Patent
Application |
20170022866 |
Kind Code |
A1 |
MONGE-BONINI; Beatriz ; et
al. |
January 26, 2017 |
SYSTEM COMPRISING A DECOMPOSITION UNIT FOR USE ON BOARD OF A
VEHICLE
Abstract
The system for use on board of a vehicle comprises a
decomposition unit (2) for decomposing a compound under catalysis
of a biological catalyst (3). The compound is for instance an
ammonia precursor, and the biological catalyst is in solid form. At
least one transfer means is present for transferring one of said
compound and biological catalyst towards and/or away from the other
one. The transfer means are for instance a moving device (15), for
instance in the form of a float.
Inventors: |
MONGE-BONINI; Beatriz;
(Brussels, BE) ; DOUGNIER; Francois; (Hever,
BE) ; VAN SCHAFTINGEN; Jules-Joseph; (Wavre,
BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PLASTIC OMNIUM ADVANCED INNOVATION AND RESEARCH |
Bruxelles |
|
BE |
|
|
Assignee: |
Plastic Omnium Advanced Innovation
and Research
Brussels
BE
|
Family ID: |
50424081 |
Appl. No.: |
15/300881 |
Filed: |
April 1, 2015 |
PCT Filed: |
April 1, 2015 |
PCT NO: |
PCT/EP15/57221 |
371 Date: |
September 30, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N 2610/12 20130101;
F01N 2610/02 20130101; Y02T 10/12 20130101; F01N 2610/1406
20130101; Y02A 50/2325 20180101; Y02T 10/24 20130101; F01N 3/2006
20130101; F01N 2240/25 20130101; F01N 2240/40 20130101; F01N 3/2066
20130101 |
International
Class: |
F01N 3/20 20060101
F01N003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2014 |
EP |
14163102.8 |
Claims
1. A system, comprising: a decomposition unit for decomposing a
compound under catalysis by a biological catalyst; and at least one
transfer unit for: transferring one of either the compound or the
biological catalyst towards the other one of the compound and the
biological catalyst to establish contact, so as to decompose the
compound under catalysis by the biological catalyst, and
transferring the one of either the compound or the biological
catalyst away from the other one of the compound and the biological
catalyst, so as to separate the compound from the biological
catalyst when decomposition is to be terminated or interrupted.
2. The system of claim 1, wherein the transfer unit is a moving
device for moving the biological catalyst towards and away from the
compound.
3. The system of claim 2, wherein the moving device is an
actuator.
4. The system of claim 2, wherein the moving device is a floating
device.
5. The system of claim 4, wherein the floating device is configured
for being overflowed by a liquid composition comprising the
compound when a vehicle comprising the system moves, so as to bring
the biological catalyst and the compound into contact.
6. The system of claim 2, further comprising a thermal conditioning
unit for thermal conditioning of the biological catalyst, when it
is not in contact with the compound.
7. The system of claim 1, wherein the transfer unit comprises at
least one fluid transfer device for transfer of the compound
towards and away from the biological catalyst.
8. The system of claim 7, further comprising a buffer tank into
which the compound or a composition comprising the compound can be
transferred so as to separate the compound from the biological
catalyst.
9. The system of claim 7, further comprising a heater for
activating the biological catalyst.
10. The system of claim 1, further comprising a magnetic device for
attracting the biological catalyst that is immobilized on a
magnetic support.
11. The system of claim 1, wherein the decomposition unit is
configured for conversion of an ammonia precursor into an ammonia
composition.
12. A vehicle, comprising the system of claim 1.
13. A method for decomposing a compound on board of a vehicle
comprising a decomposition unit provided with one of either of the
compound or a biological catalyst, the method comprising:
transferring at least one of the compound and the biological
catalyst to establish contact between both, so as to decompose the
compound under catalysis by the biological catalyst; and
transferring at least one of the compound and the biological
catalyst, so as to separate the compound and the biological
catalyst from each other, when decomposition is to be terminated or
interrupted.
14. A process, comprising: transferring a biological catalyst, a
compound, or both, with the system of claim 1, such that the
biological catalyst and the compound are in contact with each
other; and decomposing the compound in the decomposition unit with
the biological catalyst immobilized on a carrier, wherein the
decomposition unit is on board of a vehicle.
15. The process of claim 14, wherein the compound is an ammonia
precursor or a hydrogen precursor.
16. The system of claim 1, wherein the system is adapted to
function on board of a vehicle.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a system for use on board of a
vehicle comprising a decomposition unit for decomposition of a
compound, for instance an ammonia precursor.
[0002] The invention also relates to a method of operating such a
system on board of a vehicle.
[0003] The invention further relates to a vehicle comprising such a
system.
BACKGROUND OF THE INVENTION
[0004] A decomposition unit for ammonia precursor under the
catalysis of a biological catalyst, more particularly a urease
enzyme, has been proposed in several non-prepublished applications
(patent application EP 13182919.4 and patent application EP
12199278.8) of the Applicant that are herein included by reference.
In further investigations into such a system, the present inventors
have come up with further improvements that enable that the system
with the biological catalyst may be used over a longer period.
SUMMARY OF THE INVENTION
[0005] Accordingly, it is an object of the invention to provide an
improved method for preserving and protecting of the enzyme, so as
to increase its lifetime.
[0006] According to a first aspect, the invention relates to a
system for use on board of a vehicle, comprising
(1) a decomposition unit for decomposing a compound under catalysis
of a biological catalyst, and (2) at least one transfer means for:
[0007] transferring one of either the compound or the biological
catalyst towards the other one of said compound and said biological
catalyst to establish contact between of both, so as to decompose
the compound under catalysis of the biological catalyst, and [0008]
transferring said one of either the compound or the biological
catalyst away from said other one of said compound and said
biological catalyst, so as to separate between the compound and the
biological catalyst when decomposition is to be terminated or
interrupted.
[0009] According to a second aspect, the invention relates to a
vehicle comprising the system of the invention.
[0010] According to a third aspect, the invention relates to a
method of operating a method of decomposition of a compound on
board of a vehicle comprising a decomposition unit provided with
one of either a compound or a biological catalyst, comprising the
steps of: (1) transferring the other one of said compound and said
biological catalyst to establish contact between of both, so as to
decompose the compound under catalysis of the biological catalyst,
and (2) transferring said other one away from said one of either
said compound or biological catalyst, when decomposition is to be
terminated or interrupted.
[0011] According to a further aspect, the invention relates to the
use of biological catalyst immobilized on a carrier for catalysis
of decomposition of a compound in a decomposition unit on board of
a vehicle, subsequent to transferring the biological catalyst
and/or the compound for contact between the compound and the
biological catalyst.
[0012] The invention is based on the insight that the lifetime of
the biological catalyst may be increased by separation of the
catalyst from the compound or a composition thereof, when the
decomposition of the compound is not desired. The environment of
said composition may not be optimal for the biological catalyst.
For instance, the ammonia precursor urea has a pH of around 9.5,
which is an aggressive environment for a biological catalyst and
may reduce lifetime. Moreover, it is very difficult to control the
temperature around the enzymes as they are surrounded by large
volumes of liquid. Even worse, a vehicle may be used in both very
hot and very cold environments, i.e. from below 0.degree. C. up to
above 40.degree. C., which can denature biological catalyst. By
separation of the biological catalyst, thermal conditioning means
may be provided, for thermal conditioning the biological catalyst
when it is not actively catalysing decomposition of the
compound.
[0013] Functionally speaking, the biological catalyst is
transferred from a chemical conversion mode (CCM) into an enzyme
protection mode (EPM). Practically speaking, either the biological
catalyst or the compound or both of them may be transferred towards
and/or away from each other. The location of contact is not
essential and may be defined by the form in which the biological
catalyst and/or the compound are available. Thereto, the invention
provides at least one transfer means, which is understood to cover
a single transfer means to transfer the biological catalyst,
suitably in a solid form, a plurality of transfer means to transfer
biological catalyst, a single or a plurality of transfer means for
transfer of the compound, and at least one transfer means for
transfer of biological catalyst and at least one transfer means for
transfer of the compound.
[0014] According to the invention, it is preferred that the
biological catalyst is immobilized into or onto a support, more
preferably a solid support. The immobilized biological catalyst is
in one embodiment embodied as a capsule with a dimension that is
easily held and/or separated from the compound, more particularly a
liquid composition thereof. The biological catalyst is in another
embodiment immobilized onto a holding device, such as a net,
membrane, fibre, plate. The immobilized catalyst is in a further
embodiment distributed through the compound, particularly a fluid
composition thereof, when in the chemical conversion mode, and may
be separated from the fluid composition.
[0015] In a first embodiment of the invention, a moving device is
present for moving the biological catalyst towards and/or away from
the compound. This allows to bring the biological catalyst to a
predefined location in which it is not in contact with the
compound, for instance above a filling level of the liquid
composition of the compound, and/or into a specific protection
chamber. Suitably, thermal conditioning means are provided at this
predefined location, so as to protect the biological catalyst. More
particularly, the moving device is used in combination with a
holding device for the biological catalyst. This holding device may
be a fibre, a membrane, a cage, a basket, a sieve or the like.
[0016] The thermal conditioning means may be embodied as any
heating or cooling elements known by the state-of-art; for
instance, Peltier effect cells allowing cooling down, or heating up
can be used. The thermal conditioning elements may also contain
insulating elements so as to limit the energy consumption; the
thermal conditioning elements may further comprise a phase change
material so as to keep more easily and for longer period of time
the temperature range corresponding to the optimal conservation of
the enzymes.
[0017] In one embodiment, the moving device is an actuator. The
actuator may be any type of actuator, such as a solenoid, magnetic
actuator such as stepper motor, hydraulic or pneumatic piston. The
actuator may be combined with a spring device for the purpose of
pulling the biological catalyst out of the liquid composition when
a power supply is disconnected. This embodiment is deemed
particularly beneficial for the moving of the biological catalyst
in the form of one or more capsules. In one implementation the
capsules are held on a holding device in the form of a basket. In
this embodiment, the contact region is limited to a portion of the
decomposition unit, i.e. where the basket is located in the
chemical conversion mode. Distribution means such as a stirrer
and/or a pump are suitably present to arrange flow of the chemical
compound towards the biological catalyst. In another
implementation, the holding device is a sieve that is moved, and
the holding device (or a plurality thereof) has dimensions
corresponding to the decomposition unit or a chamber therein for
the biological catalyst. When moving the sieve upwards, the
capsules will be carried upwards, whereas the liquid composition
flows downwards through the sieve openings.
[0018] In an alternative embodiment, the moving device is a
floating device. The design of the floating device is suitably such
that the floating device is overflowed by the compound (i.e. a
liquid composition thereof) in the chemical conversion mode and
that the floating device arrives at a liquid surface of the said
liquid in a transfer to the enzyme protection mode. The overflowing
of the floating device with liquid will occur upon movement of the
vehicle, which results in waves of the liquid. Suitably, guides are
provided in the decomposition unit. The holding device of the
capsules is suitably present in a sub-area defined by said one or
more guides. These guides allow sliding of the floating device
while keeping the holding device of the capsule in constant
orientation relative to the decomposition unit. In a further
implementation, a level sensor is combined with the floating device
or with the guides.
[0019] In one embodiment, the system is furthermore provided with a
loading device for capsules. Suitably, the loading device is
configured for loading capsules into a storage location within the
decomposition unit, and preferably above a predefined filling level
of the liquid in the decomposition unit. This allows storage in an
efficient location. Moreover transfer from the storage location to
a holding device can be arranged in a practical manner.
[0020] Suitably, the loading device makes use of the fluid pressure
so as to arrange the capsules into a storage location inside the
decomposition unit above a filling level of the decomposition unit
with liquid. Thereto, in one suitable implementation, the loading
device is provided with an orifice in a capsule pipe for entry of
vapour, located at a desired filling level, and a degassing means
within said capsule pipe and extending to outside the composition
unit. When the liquid arrives at the orifice, the degassing of
vapour from the decomposition unit is terminated, as the degassing
means, such as a degassing line, is no longer accessible. A
pressure wave may then move capsules in the capsule pipe into a
storage location. The capsule may be disposed to the holding device
from said storage location.
[0021] According to a second embodiment of the invention, the
transfer means are embodied as at least one fluid transfer device
for transfer of the compound towards and away from the biological
catalyst. Generally, this may be a transfer of compound in or out
of the decomposition unit, or alternatively transfer of compound
inside the decomposition unit, particularly when comprising several
chambers. The fluid transfer device is for instance a pump, and may
also be embodied as a valve and downward flowing pipe. It is not
deemed necessary that the decomposition unit is emptied. Rather, it
may be sufficient to remove the compound (i.e. a composition
thereof in fluid form) to such extent, that no longer contact
occurs between the compound and the biological catalyst. Contact
may herein be provided in a suitable location or zone or (surface)
site within the decomposition unit, for instance a zone just below
an upper filling level of the decomposition unit, or alternatively
a separate chamber in the decomposition unit, suitably provided
with a valve at its entry. Combinations are also feasible, for
instance a chamber in the decomposition unit through which the
liquid is pumped, with a valve at its entry for closure and the
biological catalyst provided in the upper region of said
chamber.
[0022] In one further implementation hereof, the system further
comprises a buffer tank into which the compound or a composition
thereof can be transferred so as to get the compound out of the
contact region. In again a further implementation hereof, the
system further comprises a heater for activating the biological
catalyst.
[0023] According to a third embodiment of the invention, both the
biological catalyst and the compound are transferred. This third
embodiment most suitably uses biological catalyst immersed on a
support carrier and spread through the composition of the compound.
One example hereof is that the compound or the fluid composition
hereof is removed via a membrane and that the biological catalyst
remains behind. The biological catalyst may thereafter be
relocated, for instance to a location where it can be thermally
conditioned.
[0024] In one preferred implementation of this third embodiment,
the biological catalyst is immobilized on a magnetic support. The
immobilized biological catalyst is then attracted by means of a
magnet to a predefined location in the decomposition unit. The
compound is then transferred in as far as needed to separate the
biological catalyst from the compound. The magnetic attraction of
immobilized catalyst is known, for instance from S. Akgol, Food
Chemistry 74 (2001), 281-288, wherein invertase is immobilized onto
magnetic polyvinylalcohol microspheres for the conversion of
sucrose. Furthermore, the technology is known for the transport of
enzymes to specific locations with a human body, said transport
being driven by application of a magnetic field. Alternative
implementations of magnetic microspheres will be known to the
skilled person and are not excluded.
[0025] The decomposition unit may be operated batchwise or in a
continuous manner. Suitably, use is made of batch-wise operation.
Preferably, the control occurs by means of a time-control device or
a chemical sensor for control of the conversion. A time-control
device can be a clock or any timing mechanism driven by a motor, by
the vehicle electronic system or by another mean known by the
status of the art. A chemical sensor device can be for example a pH
sensor. When the conversion is complete, for instance, when 50% or
ideally 80% of the first composition is converted into product, the
resulting effluents may be transferred out of the converter.
[0026] Furthermore, a buffer tank may be present for containing
reaction product of the biochemical conversion by means of the
biological catalysts. The size of the buffer tank may be chosen in
dependence on the specific application and the flow rate of
reaction product.
[0027] The system of the invention is suitably provided with a tank
for storing the compound (or a composition thereof) prior to entry
into the decomposition unit. A fluid transfer device may be present
for transferring the compound from the tank to the decomposition
unit. A fluid transfer device can be for example a pump, valve,
combination of both, gravity, gravity in combination with a valve
or a valve in combination with whatever system known by the state
of the art to transfer liquid.
[0028] The compound is suitably an ammonia precursor, such as for
instance urea or a concentrated urea solution of at least 10% urea,
or a mixture known as aqua ammonia, which typically comprises
ammonium hydroxide, residue of ammonia precursor and eventually
other ammonium salts, such as ammonium bicarbonate
(NH.sub.4HCO.sub.3). In this embodiment, the reaction products may
be for instance ammonia or hydrogen suitable for use in either
selective catalytic reduction (SCR) methods for purifying exhaust
gases or for fuelling fuel cells operating on the basis of
hydrogen. Suitable biological catalysts are herein urease.
[0029] In an alternative embodiment, the compound is a hydrogen
precursor, such as ammonia or polysaccharide. Good results are
known for the enzymatic conversion of a polysaccharide such as
sucrose into hydrogen, for instance with enzymes such as invertase,
glucose dehydrogenase (GDH), hydrogenase, and glucose isomerase
(GI). This may be highly useful to provide hydrogen for use in fuel
cells.
[0030] The biological catalysts are suitable enzymes, that may be
isolated or be present as part of living microorganisms that are
feasible of producing enzymes for the biochemical conversion.
[0031] More particularly, the system of the invention is designed
for and use on board of a vehicle, including cars, trucks and
motors, using ether gasoline, diesel and optionally being a hybrid
type that can also be driven on fuel cells. The system of the
invention is thereto suitably coupled to an engine or to an SCR,
and is operative during use of the vehicle.
[0032] The features set out above for the first aspect of the
invention may also be applied to the other aspects.
BRIEF INTRODUCTION OF THE FIGURES
[0033] These and other aspects of the invention will be further
elucidated with references to the Figures, which are not drawn to
scale and are purely diagrammatical, wherein:
[0034] FIG. 1 shows a cross-sectional schematic view of the system
of the invention according to a first embodiment;
[0035] FIGS. 2a and 2b show a schematic cross-sectional view of a
first embodiment of the decomposition unit of the invention,
wherein FIG. 2a shows the converter with the enzyme in the enzyme
protection mode and FIG. 2b shows the converter with the enzyme in
the chemical converter mode;
[0036] FIGS. 3a and 3b show in a schematic cross-sectional view a
second embodiment of the decomposition unit of the invention, again
both in enzyme protection mode and in chemical converter mode;
[0037] FIGS. 4a and 4b show in a schematic cross-sectional view a
third embodiment of the decomposition unit of the invention;
[0038] FIGS. 5a and 5b show in a schematic cross-sectional view a
fourth embodiment of the decomposition unit of the invention.
DETAILED DISCUSSION OF ILLUSTRATED EMBODIMENTS
[0039] The figures are not drawn to scale. Equal reference numerals
in different figures refer to identical or corresponding
elements.
[0040] FIG. 1 shows a cross-sectional schematic view of the storage
and conversion system of the invention according to a first
embodiment. According to this embodiment, the system is a Selective
Catalytic Reduction (SCR) system, for conversion of an ammonia
precursor into ammonia and use thereof. Such SCR system is
typically present in vehicles for reduction of NO pollution. The
SCR system comprises a tank (not drawn), that is in use filled with
a commercially available liquid reductant, such as Adblue.RTM.
available from Total and matching the ISO 22241 standard
specifications. The Adblue.RTM. liquid reductant contains
32.5.+-.0.7 wt % urea. However, alternatively densities are by no
means excluded. The liquid reductant will hereinafter also be
referred to as an urea solution. It is transferred to a
decomposition unit 2 by a fluid transfer device (FTD) 10. A fluid
transfer device can be for example a pump, valve, but alternatively
gravity is exploited, in the sense that the tank and the converter
2 are connected by means of a tank with a suitable orientation. A
combination of both, gravity, gravity in combination with a valve
or the like is also feasible. The FTD 1 ensures the filling of
ammonia precursor in the decomposition unit up to a certain level.
It suitably operates under control of a level sensor (not
shown).
[0041] The decomposition unit 2 contains a catalyst composition in
solid form. The catalyst is more precisely a biocatalyst such as an
enzyme. Preferably, use is made of urease enzyme (EC 3.5.1.5) for
the conversion of urea into ammonia. Use can be made of urease of
any origin, such as Jack bean, C. Vulgaris, Pigeonpea colosynth.
The catalyst composition in solid form is more preferably embodied
as a capsule 3. Hereinafter, the invention will be further
explained with reference to a biological catalyst embodied as a
capsule. However, as discussed before, the invention may also be
used in other forms, for instance the immobilization of the
biological catalyst to a mesh or membrane, or the immobilization of
the biological catalyst onto magnetic microspheres that may be
attracted to and therewith collected by magnetic attraction
means.
[0042] The capsule 3 suitably comprises the biological catalyst
immobilized on a carrier. A variety of carriers may be used include
synthetic polymers, biopolymers, hydrogels and inorganic supports.
Examples of synthetic polymers are PVOH, EVOH, PA (nylon-6 and
nylon-6,6). Examples of biopolymers are for instance gelatin,
polysaccharides such as cellulose, starch, agarose, chitosan and
alginates. Examples of inorganic supports are alumina, silica,
zeolites and mesoporous silica. One suitable method is the
immobilization on polymeric membranes. After proper modification,
polymeric membranes can become good carriers for binding urease.
Modified nylon-6 membranes have been used to immobilize enzymes.
Alternatively, urease can be immobilized on crosslinked poly(vinyl
alcohol). The major advantage of this polymeric support is that it
can be prepared any desirable polymorphic form such as film, bead,
particle and powder with various porosities and surface areas.
[0043] Reference is made to following articles, which describe the
immobilization of urease on nylon-6 membranes and crosslinked
poly(vinyl alcohol) beads and the relative activity of the
immobilized urease enzyme as a function of the pH and temperature:
A. Baran Teke and S. Hamarat Baysal (2007). Immobilization of
urease using glycidyl methacrylate grafted nylon-6-membranes.
Process Biochemistry Volume 42, Issue 3, March 2007, Pages 439-443;
S. Rejikumar and Surekha Devi (1998). Preparation and
characterization of urease bound on crosslinked polyj vinyl
alcohol), Journal of Molecular Catalysis B: Enzymatic 4: 61-66.
[0044] Both publications are herein included by reference.
[0045] The capsules and/or other solid forms are preferably
provided with a diameter in the range of 10 microns-10 cm,
preferably 1 mm-1 cm, so as to handle them individually. Thereto,
the capsule may furthermore contain a shell of protective materials
such as gelatine, glycerol and the like. Furthermore, the capsule
may be based on microencapsulation, comprising a plurality of beads
with enzyme immobilized on carrier in a matrix. The matrix may be
herein optimized to be slowly dissolvable, in dependence of the pH
or temperature of the reaction medium, so as to obtain
modified-release capsules, as known per se in the art of capsule
manufacturing, particularly for pharmaceuticals. In one preferred
embodiment, use is made of a capsule that does not--or at least not
substantially--disintegrate. The carrier is herein preferably
defined as a porous body, and the enzyme is suitably located at a
surface inside said porous body.
[0046] In one suitable embodiment, the catalyst is an urease
enzyme. This is suitable for the conversion of an ammonia precursor
such as urea. Suitably, the urease enzyme is immobilized on a
biopolymer carrier. The use of such a carrier results in improved
stability. Examples of carriers are gelatine, alginates and
chitosan. The use of chitosan is deemed highly suitable, since it
tends to increase optimum pH of the urease to a higher pH,
resulting in optimum activity in the ammonia precursor composition
e.g. solution.
[0047] In the present example, use is made of a batchwise
operation. The decomposition unit 2 is equipped with a heater 4 in
order to thermally activate the enzyme. When the conversion has
reached a predefined conversion degree, for instance when 50% or
more of the ammonia precursor is converted into ammonia solution,
or ideally when at least 80% or more of the ammonia precursor is
converted into aqua ammonia, the resulting effluents are then
transferred to a first buffer tank 8 by the a second fluid transfer
device (FTD2). The conversion may continue in this first buffer
tank 8 (if necessary the effluents of buffer tank 8 will be
transferred back to de decomposition unit by FTD3). The effluents
are thereafter transferred from the first buffer tank 8 to a second
buffer tank 9 by the FTD4, as the conversion is complete or has
reached another final conversion degree. The progress of the
conversion is suitably controlled by a time-control device or by a
chemical sensor. A time-control device can be a clock or any timing
mechanism driven by a motor, by the vehicle electronic system or by
another mean known by the status of the art. A chemical sensor
device can be for example a pH sensor or an ammonia sensor.
Whenever necessary the effluents are sent to downstream tank by the
FTD5.
[0048] In accordance with the invention, the enzyme may be
transferred from a chemical conversion mode (CCM) to an enzyme
protection mode (EPM) and vice versa. In the EPM, the system is
configured so that there will be substantially no contact between
the enzymes and the ammonia precursor. In the embodiment shown in
FIG. 1, the ammonia precursor solution is pumped away, so as to
transfer the enzyme from the CCM to the EPM. Whenever the chemical
conversion operation is interrupted, FTD2 is activated so as to
empty the decomposition unit 2 and stop the contact between the
enzymes and the ammonia precursor. The enzymes are then in enzyme
protection mode (EPM). The partially converted effluents are stored
in the first buffer tank 8. When the conversion has to be
restarted, FTD3 is activated so as to send the partially converted
effluents back to the decomposition unit 2 to continue conversion
and therefore switching back to the chemical conversion mode (CCM).
When converted to a sufficient conversion degree, the resulting
ammonia solution can be transferred to the second buffer tank 9.
The solution in the second buffer tank 9 is then ready to be sent
to downstream tank by the FTD5.
[0049] Optionally, thermal conditioning elements surrounding the
enzymes 11 can be activated when the conversion operation is
interrupted (in EPM) so as to keep the enzymes at optimal
temperature and further extent enzymes useful life. This can be any
heating or cooling elements known by the state-of-art; for
instance, Peltier effect cells allowing cooling down, or heating up
can be used. The thermal conditioning elements also contain
insulating elements so as to limit the energy consumption; the
thermal conditioning elements can also contain phase change
materials so as to keep more easily and for longer period of time
the temperature range corresponding to the optimal conservation of
the protein components activity.
[0050] In an alternative embodiment, the system can be designed to
contain fewer tanks, or even only one tank with subdivisions (not
represented here).
[0051] FIGS. 2a and 2b show the decomposition unit 2 according to a
first embodiment of the invention. The embodiment shown in FIGS. 2a
and 2b could be combined with the embodiment shown in FIG. 1, or be
an alternative thereto. In case of being an alternative, the
decomposition unit 2 shown in FIG. 2 is suitably part of a storage
and conversion system further comprising a tank for the composition
of a chemical compound, more particularly a composition of an
ammonia precursor, and a buffer tank for the sufficiently converted
composition. Furthermore, a storage unit for the catalyst
composition in solid form, i.e. capsules, is suitably present.
[0052] According to the embodiment of FIGS. 2a and 2b, the
decomposition unit 2 is equipped with a moving device 12 allowing
to submerge the capsules 3 comprising the catalyst composition into
the liquid composition of the chemical compound. This will transfer
the catalyst composition and the system from an enzyme protection
mode (EPM), shown in FIG. 2a, into a chemical conversion mode
(CCM), shown in FIG. 2b. The moving device 12 is further capable of
operating in the reverse direction, i.e. to transfer the catalyst
composition from the CCM into the EPM. The moving device 12 is in
this embodiment an actuator. Any type of actuator may be applied,
such as a solenoid, a magnetic actuator, a stepper motor, hydraulic
or pneumatic piston. The actuator 12 may be combined with a spring
or any element acting as a spring. This has the advantage that the
capsules 3 may be pulled out the liquid composition, and therewith
transferred from the chemical conversion mode into enzyme
protection mode, whenever a power supply is disconnected.
[0053] FIGS. 3a and 3b show the decomposition unit 2 according to a
second embodiment. Herein, the moving device 12 comprises one or
more thermal conditioning elements 13. Therewith, the capsules 3
comprising the catalyst composition can be maintained within a
temperature range in which the biocatalyst is conserved, i.e. is
kept alive. The temperature range is suitably set so as to achieve
optimum conservation.
[0054] Furthermore, the thermal conditioning elements may be under
the control of a sensor and controller; for instance, the thermal
conditioning elements could maintain the enzymes at their optimal
operation temperature, typically around 37.degree. C., as long as
the duration of the enzyme protection mode is shorter than a
predefined limit. If however the duration of the enzyme protection
mode exceeds that limit, the temperature could be reduced, so as to
bring the enzymes into a sleep-mode. This sleep mode will be at a
temperature in which the enzymes cannot freeze. In a further
implementation hereof, the thermal conditioning elements may be
controlled so as to carry out a pretreatment, wherein the capsules
3 are gradually brought to their operation temperature prior to a
first use.
[0055] The thermal conditioning elements 13 are for instance
embodied as heating or cooling elements known by the state-of-art;
for instance, Peltier effect cells allowing cooling down, or
heating up can be used. Moreover, the thermal conditioning elements
may contain--alternatively or additionally--thermally insulating
elements so as to limit the energy consumption; the thermal
conditioning elements can also contain phase change materials so as
to keep more easily and for longer period of time the temperature
range corresponding to conservation of the enzymes.
[0056] In again a further embodiment, the moving device 12 may be
further provided with means for providing cleaning liquid. Such
cleaning liquid is for instance water. The means for provided
cleaning liquid may be embodied as a jetting or spraying device.
Such means are intended for operation after conversion into the
enzyme protection mode, so as to remove any remaining chemical
compound from the capsules. The means for the provision of cleaning
liquid may alternatively be configured such that they can operate
on the capsules 3 when those are in the enzyme protection mode, and
more particularly brought at a location above a surface of the
liquid composition of the chemical compound. The means for
providing cleaning liquid could further be used, when the capsules
3 are in enzyme protection mode, so as to control the humidity of
the capsules.
[0057] FIGS. 4a and 4b show the decomposition unit 2 according to a
third embodiment of the invention. As in FIGS. 2a and 2b, FIG. 4a
shows the decomposition unit 2 with the capsules 3 in enzyme
protection mode and FIG. 4b shows the decomposition unit 2 with the
capsules 3 in chemical conversion mode. Herein, the moving device
is embodied as a floating device 14. The advantage of this floating
device 14 is that it transfers from enzyme protection mode (EPM) to
chemical conversion mode (CCM) automatically, i.e. without any
powered means. The embodiment thereto makes use of the effect that
any movement of the vehicle generates waves in the surface of the
liquid composition of the compound (for instance an ammonia
precursor). Due to the--sloshing--waves, liquid will be embarked
onto the floating device 14. As a consequence, the floating device
14 will sink or at least be immersed into the liquid composition of
the compound. Therewith, contact is established between the
biological catalyst and the compound, and the biological catalyst
is transferred into the chemical conversion mode (CCM), as shown in
FIG. 4b.
[0058] After stopping the vehicle, the floating device 14 moves
upwards again. Preferably, draining holes 15 are present that allow
the evacuation of the embarked liquid. After a certain period of
time (for instance 1 hour), the floating device 14 has got to the
surface of the liquid composition, and the capsules 3 are brought
to a position above this surface. Therewith, the enzymes have been
transferred to the enzyme protection mode (EPM), as shown in FIG.
4a. The speed at which the floating device 14 arrives at the
surface of the liquid, is suitably predefined. Suitably, the speed
is relatively low, so as to arrange that the biochemical conversion
continues for some time after stopping the vehicle. This allows for
instance to have enough converted effluents at the time the vehicle
is restarted.
[0059] The decomposition unit 2 of this embodiment is furthermore
provided with guides 16. These guides 16 allow the sliding of the
floating device 14 while keeping the device structure in constant
orientation versus the tank. More particularly, a couple of guides
16 are used in between of which the capsules 3 are arranged,
preferably in or on top of a holding device. The floating device
may herein be provided with a bridging portion and floating
elements. The bridging portion extends between the guides 16 and is
in contact with the biological catalyst or preferably the holding
device. The floating elements are present on opposed sides of the
guides 16. Guides 16 can be of any type known in the state of the
art, and can be single or multiple. Suitably, the guides 16
comprise an aperture or channel, through which said bridging
portion extends, and which further limits the movement of the
floating device 14. Level sensing function may be combined with or
embarked into this floating device 14 or on the guides.
[0060] FIGS. 5a and 5b show in schematic, cross-sectional view a
further embodiment of the invention. This embodiment more precisely
shows a loading device for loading capsules 3. The loading device
comprises a filler pipe 7, a vertical or skewed pipe 17, a
degassing orifice 18 and a degassing line 19. The capsules 3 are
inserted in the filler pipe 7, for instance from a storage unit or
from an external source. Subsequently thereto, the liquid
composition of the chemical compound, particularly an ammonia
precursor, is filled into the decomposition unit 2. This suitably
occurs via the same filler pipe 7. Since the density of the
capsules 3 is typically lower than the density of the liquid, the
capsules 3 move upwards into the vertical or skewed pipe 17 under
the liquid pressure of the liquid composition of the chemical
compound. After that the ammonia precursor level reaches the level
of the degassing orifice 18, the vapour pressure increases inside
the decomposition unit 2. Vapour will particularly collect within a
vapour dome above the surface of the liquid. The background of the
rising pressures is that the vapor can no longer escape through the
degassing line 19, when the liquid blocks the degassing orifice 18.
This blocking of the orifice 18 provokes the increase of the level
of liquid in the fill pipe 7 (and so the end of the refilling
operation). Additionally, the blocking provokes a pulse of pressure
and liquid in the vertical pipe 17 pushing the capsules 3 into a
storage chamber 20 (FIG. 4b). Devices such as flapper doors 21 can
be used to control the exit of capsules 3 from the storage chamber
20, and furthermore also to control the entry of capsules into the
storage chamber 20 (i.e. other flapper doors).
[0061] When fresh capsules 3 are to be added into the liquid and/or
into a moving device operating therein, capsules 3 can be
transferred thereto by activating a transfer means. Hereto any
transfer means as known in the art may be used: release of a
flapper door 21 by mechanical means, for instance release of a
mechanical locker due to the contact of the empty floating device
with the storage chamber, or by a controlled mechanism. Such adding
of one or more capsules 3 may take place for instance right after
the loading of new capsules into the storage chamber 20, or upon
detection of loss of enzyme activity of the capsules 3 in use. A
sensor, such as a pH sensor could be used thereto. Furthermore, a
duration of the actual use could be registered. In again a further
embodiment, the enzyme protection mode could be provided with test
means for testing the enzyme activity.
[0062] In the embodiment shown in FIGS. 5a and 5b, the capsule
loading device is combined with the use of a floating device 14, as
shown in FIGS. 4a and 4b and as discussed hereinabove. However, the
loading device may alternatively be used in combination with any
actuator as shown in FIG. 2a-3b. Moreover, it is not excluded that
the loading device is used so as to apply capsules 3 directly into
the liquid composition.
[0063] It will be understood that thermal conditioning elements may
be applied if so desired, either in or around the storage chamber
20, or to the floating device 14 or to both. Thermal conditioning
elements that are able to withstand an ammonia precursor solution
are for instanced wired elements, suitably with a relatively high
resistance.
[0064] In an alternative embodiment, means for magnetic attraction
may be present. This means is for instance a magnetic core, but
could alternatively be a magnetic plate arranged adjacent to a wall
of the decomposition unit (inside or outside thereof). These means
may be activated when the system is ready to switch between
chemical conversion mode and enzyme protection mode. The magnetic
means will then attract the biological catalyst immobilized in any
kind of magnetic polymer, for instance immobilized onto magnetic
polyvinylalcohol microspheres, just before the system switches to
the enzyme protection mode (not represented here). This switch may
for instance be arranged in that the magnetic core is transferred
by a moving device to outside the contact region. Alternatively,
the compound may be pumped away.
* * * * *