WO2011120522A1

WO2011120522A1 - A method for cleaning a medium in a reactor

Info

Publication number: WO2011120522A1
Application number: PCT/DK2011/000022
Authority: WO
Inventors: Jakob Vibe Pedersen
Original assignee: P & I Engineering Aps
Priority date: 2010-03-30
Filing date: 2011-03-28
Publication date: 2011-10-06

Abstract

A method for cleaning an untreated medium in a reactor, with a plurality of carrier devices extending radially from the shaft. The method comprising the steps of: feeding an untreated medium into the reactor through an untreated-medium inlet; rotating the shaft by means of a motor; outputting the treated medium through an treated-medium outlet; and outputting the receiving medium through an receiving- medium outlet.

Description

A METHOD FOR CLEANING A MEDIUM IN A REACTOR

FIELD OF THE INVENTION

The present invention relates to a method for cleaning an untreated medium in a reactor. In particular the present invention relates to a method for cleaning an untreated high viscosity medium and/or an untreated medium which contains a large percentage of solid matter.

BACKGROUND OF THE INVENTION

Most industrial processes have an output containing particles and/or other matter which for one reason or the other Is undesirable to emit Into the nature. For this reason, many countries have prohibited such emissions or require that the output matter is cleaned prior to emission. In order to fulfil this goal, many devices and methods have been developed.

One such device is vertical columns where untreated medium flows from the bottom towards the top and contacts a receiving medium during the upwards flow. In order to decrease the flow rate - and thus time the untreated matter is in contact with the receiving medium - stationary mixers may be provided. However, such static mixers require that the viscosity of the untreated medium and the receiving medium are low. Moreover, even low viscosities will not prevent deposition of layers of the untreated medium on the static mixers. Such mixers are difficult to clean as they are provided inside the column. Moreover the deposited material is from time to time Insoluble and thus difficult to remove except by use of mechanical methods.

It is an object of one or more embodiments of the present invention to provide a method for cleaning a medium or cleaning with a medium which contains more solid than fluid matter or at least a high solid contents, Furthermore, it Is an object of embodiments of the present Invention to provide a method for cleaning a high viscosity medium or cleaning with a high viscosity medium.

Furthermore, it is an object of embodiments of the present invention to provide a method for cleaning and cooling or heating the media in the same unit.

Moreover, it is an object of embodiments of the present Invention to provide a method for cleaning the cleaning device which is adapted to clean a medium, during use of the cleaning device. It is an object of one or more embodiments of the present invention to provide a method in which undesirable particles or gasses may be removed from a gas or medium. E.g. removal of non-flammable gasses from a flammable gas.

Moreover, it Is an object of one or more embodiments of the present invention to provide a cleaning device which can be integrated into a generally horizontally extending container.

Moreover, it is an object of one or more embodiments of the present invention to provide a cleaning device which is adapted to supply or remove thermal energy to untreated medium and the receiving medium during the treatment thereof. DESCRIPTION OF THE INVENTION

The present invention relates to a method for cleaning an untreated medium in a reactor, the reactor comprising:

- a reactor housing adapted to accommodate the untreated medium which contains unwanted matter and a receiving medium which is suitable for receiving the unwanted matter ;

- a rotatable shaft extending in a longitudinal direction of the reactor housing;

- a motor arranged to rotate the shaft;

- a plurality of carrier devices extending radially from the shaft, such that rotation of the shaft causes each carrier device to rotate about the shaft whereby each carrier device repeatedly is rotated into the untreated medium and subsequently

(out of this untreated medium and) into the receiving medium, such that at least a part of the untreated medium is brought into contact with the receiving medium by being moved by the carrier device Into said receiving medium, wherein at least two of the carrier devices are provided in different angular positions relative to the shaft;

- at least one untreated-medium inlet for feeding the untreated medium into to the reactor housing;

- at least one treated-medium outlet for outputtlng the treated medium from the reactor housing; and - at least one receiving-medium outlet for outputting the receiving medium; the method comprising the steps of:

- feeding the untreated medium into the reactor through the untreated-medium inlet;

- rotating the shaft by means of the motor; - outputting the treated medium through the treated-med!um outlet; and

- outputting the receiving medium through the receiving-medium outlet.

Rotation of the carrier devices causes at least a part of the untreated medium to be advanced into the receiving medium. The result is that the untreated medium is brought into contact with the receiving medium which will receive at least a part of the unwanted matter. For each rotation of the carrier devices, a part of the unwanted matter is transferred to the receiving medium. Accordingly, the untreated medium will be cleaner and cleaner and gradually turn into the treated medium.

It will be appreciated that the untreated medium gradually will become cleaner and cleaner and thus gradually turn into the treated medium, however, in the context of the present invention, the term treated medium is only used to designate the medium in the state it leaves the reactor housing through the treated-medium outlet.

Moreover it will be appreciated that due to the design of the machine where the untreated medium is gradually becoming cleaner and cleaner, there is little or no direct contact between the untreated medium in one end of the device and the treated medium in the opposite end of the device. This provides the advantage that treated medium is not contaminated by the untreated medium.

In one embodiment, the shaft of the reactor extends In a substantially horizontal direction and the treated and untreated mediums flows in the horizontal direction. This provides the advantage that the risk of clogging of the device is reduced. Moreover, this provides the advantage that rotation of the carrier devices about the shaft results in an increased contact between particles of different size as the carrier devices stirs the content. Moreover, the present invention provides the advantage that It allows for more viscous fluids to be subjected to the cleaning process. This is contrary to a vertical column where viscous fluids have a tendency to clog the vertical column. Moreover, the present invention allows for use very small quantities of liquid e.g. water, in the cleaning process as the fluid will not be flushing through the system by gravity as the case with vertical columns. The term "untreated medium" shall be understood as a solid matter and/or liquid and/or gasses which contains unwanted matter in an undesired quantity (e.g. vol %, or weight %).

The term "unwanted matter" shall be understood as one or more of solid matter (e.g. Particles), liquid and gasses, which is/are unwanted in the untreated medium and thus Is/are to be removed from the untreated medium so as to achieve a treated medium. In some embodiments, the solid matter and/or gas may be suspended in a liquid based untreated medium.

The term "treated medium" shall be understood as a medium from which ali or some of the unwanted matter have/has been removed. In some embodiments, the term is to be understood such that substantially all the unwanted matter has been removed, e.g. such that only insignificant levels of the unwanted matter remains in the treated medium.

In another embodiment, only a predetermined percentage is removed e.g. such that the treated medium only contains unwanted matter in quantities (e.g. vol %, weight % or ppm) which are below official thresholds for such matter. In yet anther embodiment, the unwanted matter is removed to a degree where the treated medium achieves a predetermined property e.g. that the treated medium is ign!table/flammable. In the latter embodiment, the process of the present invention may be used to remove nonflammable gasses from flammable gasses. The reactor housing may form a substantially horizontally extending body. The reactor body will in most embodiments define an annular body with a predetermined cross- section such as a circular cross-section, an oval cross section, a polygonal cross-section. Accordingly, the reactor body will in some embodiments define a circular body. The ends of the annular body will typically be closed by end surfaces. In one embodiment, the rector housing Is adapted to be pressurised either such that the pressure inside the reactor is above the ambient pressure or such that the pressure Is below the ambient pressure in the vicinity of the reactor. The reactor body may comprise a metal or plastic material. In one embodiment, the reactor body is made from fibre glass and is reinforced by means of metal structure. The reactor body may be formed by two or more parts which have been attached to each other e.g. by glueing, welding or any other known fastening method. The walls of the reactor housing may be impermeable to liquids and/or gasses.

The respective density of the untreated medium and the receiving medium determines which of the two that will be positioned in the lower part of the reactor housing and which will be positioned in the upper part thereof. In one embodiment, the density/buoyancy of the untreated medium will cause it to be provided in the lower part of the reactor housing while the receiving medium wilt be forced Into the upper part of the housing.

In one embodiment, the untreated medium may be a fluid or solid matter and the receiving medium may be a gas e.g. air. Accordingly, in the latter embodiment, the density of the untreated medium may be higher than the density of the receiving medium, this will cause the untreated medium to be positioned in the lower part of the reactor housing and the receiving medium to be positioned in the upper part of the housing. Upon rotation of the shaft, the carrier devices will be rotated down into the untreated medium and subsequently up into the receiving medium. The carrier devices will lift at least a part of the untreated medium up into the receiving medium such that this part of the untreated medium Is brought into contact with the receiving medium. The contact between the untreated medium and the receiving medium will cause a part of the unwanted medium to be transferred from the untreated medium to the receiving medium.

Alternatively, the untreated medium may be lighter than the receiving medium whereby the density/buoyancy of the untreated medium will cause it to be positioned on top of the receiving medium.

In one embodiment, the untreated medium may be a gas such as exhaust gas, while the receiving medium may be a fluid such as water. Accordingly, the density of the receiving medium may be higher than the density of the untreated medium. This will cause the receiving medium to be positioned in the lower part of the reactor housing while the untreated medium will be positioned in the upper part of the reactor housing. Upon rotation of the shaft, the carrier devices will be rotated up into the untreated medium and subsequently down into the receiving medium. The carrier devices will force at least a part of the untreated medium down into the receiving medium such that this part of the untreated medium is brought into contact with the receiving medium. Additionally the carrier devices will lift at least a part of the receiving medium up into the untreated medium. The contact between the untreated medium and the receiving medium will cause a part of the unwanted matter to be transferred from the untreated medium to the receiving medium.

The rotatable shaft may extend through one or more of the end surfaces of the reactor housing, and a liquid and/or gas tight seal may be provided in the area of the reactor housing where the shaft penetrates the housing. The seal may take the form of an 0- ring extending around the shaft. The shaft may comprise a metal material and/or a plastic material. In one embodiment, the shaft is reinforced e.g. by means fibers such as fiber glass and/or Kevlar. A motor is provided for rotating the shaft, and gear mechanism may interconnect the shaft and the motor.

One or more to the carrier devices may by fastened to the shaft. Alternatively, the shaft and the carrier devices may form a monolithic element, such that no seams (e.g.

welding seams) are provided in the transition between the carrier devices and the shaft.

The carrier devices extend radially from the shaft, i.e. in the direction of a radius of the shaft. One or more of the carrier devices may define a carrier plate or element which is interconnected with the shaft by means of a carrier arm. The arm may be straight e.g. such that it extends substantially in the radial direction relative to the shaft.

Alternatively, the arm may be curved. In one embodiment, the carrier devices are provided in the form of discs extending radially from the shaft.

The carrier plate or elements are adapted to carry at least a part of the untreated medium into the receiving medium. Alternatively, or as a supplement, the carrier plates/elements are adapted to carry at least a part of the receiving medium into the untreated medium. In cases where the receiving medium is lighter than the untreated medium, the buoyancy of the receiving medium will cause the receiving medium to flow towards the receiving medium which is provided above the untreated medium, when the carrier plates/elements have forced the receiving medium Into the untreated medium. Similarly in embodiments, where the receiving medium is heavier than the untreated medium, gravity will cause the receiving medium to fall into the untreated medium, when the carrier plates/elements have lifted the untreated medium up into the receiving medium.

The carrier plates/elements may be designed so as to lift as much of the untreated medium into the receiving medium provided thereabove as possible. Alternatively, the carrier plates/elements may be designed so as to advance the untreated medium into the receiving medium for as long a period of time as possible. In other words, the carrier plates/elements may be designed so as to lift the heavier medium up into the lighter medium and force the lighter medium into the heavier medium, which due to gravity is provided below the lighter medium. In one embodiment, the carrier devices are distrusted around the shaft such that an angle of 180 degrees are defined

circumferentially relative to the shaft between two carrier devices which are neighboring in the longitudinal direction of the shaft, such as 150 degrees, such as 135 degrees, such as 120 degrees, such as 90 degrees, such as 60 degrees, such as 45 degrees, such as 30 degrees, such as 20 degrees, such as 10 degrees. In one embodiment, the carrier devices are distributed at angles which when divided into 360 degrees will not yield an integer, examples are 70 degrees and 37 degrees.

In one embodiment, one carrier device is provided for every meter of the shaft, such as two carrier devices, such as three carrier devices, such as four carrier devices, such as five carrier devices, such as 10 carrier devices, such as 15 carrier devices, such as 20 carrier devices, such as 25 carrier devices, such as 30 carrier devices.

The untreated-medium inlet may be provided in an upstream end of the reactor housing and the treated-medium outlet may be provided In the longitudinally opposite downstream end of the reactor housing. Thus during use, the untreated medium flows from the untreated-medium inlet towards the treated-medium outlet.

The at least one receiving-medium outlet and the at least one receiving-medium inlet may be provided In opposite ends of the reactor housing. In one embodiment, the receiving-medium outlet Is provided in the same end as the untreated-medium inlet and the receiving-medium inlet is provided In the same end as the treated-medium outlet. In other embodiments, the positions of the receiving-medium inlet and outlet are reversed.

The steps of feeding the untreated medium, rotating the shaft, outputtlng the treated medium and outputtlng the receiving medium may be preformed concurrently and/or continuously. In another embodiment, the untreated medium is initially feed into the reactor housing. Subsequently, the shaft is rotated, and thereafter the treated medium and the receiving medium are outputted.

In some embodiments, the reactor housing further comprises at least one receiving- medium inlet for feeding the receiving medium into the reactor housing. In the latter embodiment, the method may comprise the step of: - feeding the receiving medium into the reactor housing through the receiving- medium inlet.

In such embodiments, the step of feeding the receiving medium may be performed continuously and concurrently with the above mentioned steps. In other embodiments, the step of feeding the receiving medium is performed together with the step of feeding the untreated medium Into the reactor housing and prior to rotating the shaft.

It will be appreciated that the interior of the reactor may be contaminated during use. Such contamination may be formation of layers or deposit on the inner surfaces of the reactor housing and/or the shaft and/or the carrier devices. The formed layers/deposits may comprise one or more of unwanted matter, the untreated medium, the treated medium and the receiving medium.

Accordingly, the reactor may comprise means for cleaning at least a part of the interior of the reactor (the Inner surfaces of the reactor housing and/or the shaft and/or the carrier devices) during standstill and/or use of the reactor. In one embodiment, the method further comprises the steps of:

- rotating the shaft in a first rotational direction, and subsequently

- rotating the shaft in a second opposite rotational direction.

By reversing the rotational direction, some or all of the deposited material may be removed from the surface on which it was deposited. This could be a surface of the carrier devices and/or a surface of the shaft and/or a surface of the reactor housing.

In one embodiment, the shaft is initially rotated in a clockwise direction and

subsequently in a counter clockwise direction.

In one embodiment, the method may further comprise the step of operating the shaft such that turbulence created by each carrier device constantly changes position relative to the respective carrier device. This may be achieved by constantly varying the rotational speed and/or direction.

The method may further comprise the steps of:

- rotating the shaft at a first velocity, and subsequently - rotating the shaft at a second velocity, the second velocity being different from the first velocity.

It will be appreciated that this will also cause the deposited layers to loosen and break off. This is especially advantageous in relation to deposited layers which are difficult or impossible to dissolve. In one embodiment, the changing of the rotational velocity and the rotational direction are combined. Thus in one embodiment, the carrier devices are rotated in a first rotational direction and at a first rotational velocity, and subsequently the carrier devices are rotated in the opposite second rotational direction and at a second rotational velocity. As the contact between the untreated medium and the receiving medium is essential for transferring the unwanted matter from the untreated medium to the receiving medium, it will be appreciated that the carrier devices may advantageously be designed so as to keep the untreated medium in the receiving medium for as long as possible. Accordingly, the step of rotating the shaft may comprise the step of: - rotating the shaft with an rotational velocity that prevents the medium from being ejected at least partly vertically from the carrier device.

In one embodiment, the method further comprises the step of adding a substance to the untreated medium during operation of the reactor. The substance may be a cleaning substance, such as a substance capable of causing sedimentation of predetermined particles or substances.

In one embodiment, the substance is added at a point downstream the untreated- medium inlet and upstream the treated-medium outlet. This may be done by means of a chemical substance inlet which is provided between the untreated-medium inlet and the treated-medium outlet.

In yet another embodiment, the reactor is accommodated in a container which is dimensioned such that it may be transported on a truck. Such a container may be a shipping container, or an ISO container.

BREIF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the drawings, in which

Fig. 1 discloses a first embodiment of the reactor,

Fig. 2 discloses a second embodiment of the reactor, and

Fig. 3 discloses a third embodiment of the reactor.

DETAILED DESCRIPTION OF THE DRAWINGS Fig, 1 discloses a reactor 100 comprising a reactor housing 102 which is adapted to accommodate an untreated medium 104 that is feed into the reactor housing 102 via the untreated-medium inlet 106 and feed out of the reactor 100 via the treated-medium outlet 108. A receiving medium 110 is provided for receiving unwanted matter (not visible in the figure) from the untreated medium 104. The receiving medium 110 is feed into the reactor housing 102 via a receiving-medium inlet 112 and out of the reactor housing 102 through the receiving-medium outlet 114. The untreated medium 104 flows in the right direction in the figure, and the receiving medium 110 flows in the left direction in the figure. This causes a contra flow between the untreated medium 104 and the receiving medium 110. The reactor 100 comprises a shaft 116 which at its ends is supported by bearings 117 and which may be rotated by means of the motor 118. A plurality of carrier devices 120 extend radially from the shaft 116. When the motor 118 Is operated, the carrier devices 120 are rotated about the shaft which extends in a generally horizontal direction. This rotation causes the untreated medium 104, to be forced into the receiving medium 110, whereby the untreated medium 104 In the form of air bubbles 122 Is forced into the receiving medium 110. Similarly, the receiving medium 110 is elevated into the untreated medium 104 whereby droplets 124 of the receiving medium 110 is formed in the untreated medium 104.

Due to the counter flow of the receiving medium 110 and the untreated medium 104 combined with the rotation of the carrier devices 120 about the shaft, the unwanted matter is transferred from the untreated medium to the receiving medium.

The content of the reactor may be cooled or heated by adding a temperature regulating gas/or liquid through the temperature regulating media inlet 126 and outputting the temperature regulating media through the temperature regulating media outlet 128. Chemical substances may be added by the additive inlet 130, such additives may be suitable for causing sedimentation of predetermined particles or substances in the reactor 100.

In the embodiment of Fig. 1 the receiving medium 110 is provided in the form of a liquid which is heavier than the untreated medium 104 which is provided in the form of a gas. As is described previously, this may be reversed such that the untreated medium 104 is provided in the form of a liquid which is heavier than the receiving medium 110 which is provided in the form of a gas.

Fig, 2 discloses a reactor 100 comprising a reactor housing 102 which is adapted to accommodate an untreated medium 104 in the form of an exhaust gas which often will contain vapour. The untreated medium 104 is feed into the reactor housing 102 via an untreated-medium inlet 106, and Is feed out of the reactor 100 via the treated-medium outlet 108. Vapour contained in the untreated medium will condense on the inner surface 132 of the reactor housing and form condensed droplets 134. Gravity will cause the condensed droplets 134 to be collected in the lower part of the reactor housing 102. The collection of condensed droplets 134 will serve as a receiving medium 110. The reactor comprises a shaft 116 which at its ends is supported by bearings 117 and which may be rotated by means of the motor 118 which Is connected to the shaft which extends in a generally horizontal direction. A plurality of carrier devices 120 extend radially from the shaft 116, thus when the motor 118 is operated, the carrier devices 120 rotated about the shaft.

Rotation of the shaft 116 causes the untreated medium 104 (the gas) to be forced into the receiving medium 110 (the collection of the condensed droplets), whereby the untreated medium 104 in the form of air bubbles 122 is forced into the receiving medium 110. Additionally, the receiving medium 110 is elevated into the untreated medium 104 whereby droplets 124 of the receiving medium 110 is formed on the surfaces of the carrier devices 120.

In some embodiments, the amount of vapour is sufficient to provide the desired amount of receiving medium. However, if the amount of vapour is insufficient, the receiving medium may be supplied with further liquid via a receiving medium Inlet 112.

In order to collect particles which settle in the lower part of the reactor housing 102, one or more sedimentation collection units 136 may be provided. The sedimentation connection units may be adapted to be emptied by hand and/or by means of pump and/or any other suitable means for removing settled particles. By collecting the settled particles, the receiving medium 110 is kept cleaner and thus the use of liquid may be minimized considerably.

In order to regulate the acidity (the pH-value) of the receiving medium and/or the untreated medium, the reactor housing 102 comprises one or more additive inlets 130 by means of which an acidity-regulating medium may be added. Examples of such additives are caicite, calcium hydroxide, chalk, milk of lime, acids such as Sulfuric acid, Phosphoric acid or Formic acid.

Fig. 3 discloses a reactor 100 for use In a diabatlc distillation process. The reactor 100 comprising a reactor housing 102 which is adapted to accommodate an untreated medium 104 that is feed into the reactor housing 102 via the untreated-medium inlet 106 and feed out of the reactor 100 via a first and a second treated-medium outlet 108', 108". During use, the reactor housing 102 is heated by means of a heating system comprising a heat pump 138 which is used as a heat exchanger. The heat pump 138 is fluidly connected to a heating inlet 140 which is used to pump a heated medium into a heating chamber 142 that encirculates the reactor housing 102. Moreover the heat pump is fluidly connected to a heating outlet 144 by means of which the heating medium is feed out of the heating chamber 142 and Into the heat pump 138. Furthermore, the heating pump is fiu!dly connected to a cooling inlet 146 which is used to pump a cooling medium into a cooling chamber 148 that encirculates the reactor housing 102.

Moreover, the heat pump is fluidly connected to a cooling outlet 150 by means of which the cooling medium is feed out of the cooling chamber 148. It will be appreciated that the heat pump 138 transfers thermal energy from the cooling medium to the heating medium, where the temperature of the heating medium Is elevated and the temperature of the cooling medium is decreased. As the left part of the reactor housing 102 causes the untreated medium 104 to be heated and the right part of the reactor housing 102 causes the untreated medium 104 to be cooled, a distillation process will occur. Thus, liquid flowing out of the first treated- medium outlet 108' has a higher boiling point than liquid flowing out of the second treated-medium outlet 108".

Furthermore the provision of the heating changer 142 causes the untreated medium 104 to boil in the area of the heating chamber. In Fig. 3 this is indicated by air bubbles 122. Unwanted matter is removed by means of a unwanted matter outlet 152.

Claims

1. A method for cleaning an untreated medium in a reactor, the reactor comprising:

- a motor arranged to rotate the shaft;

- at least one untreated -medium inlet for feeding the untreated medium into to the reactor housing;

- at least one treated-medium outlet for outputting the treated medium from the reactor housing; and - at least one receiving-medium outlet for outputting the receiving medium; the method comprising the steps of:

- rotating the shaft by means of the motor; - outputting the treated medium through the treated-medium outlet; and

- outputting the receiving medium through the receiving-medium outlet.

2. A method according to claim 1, wherein the reactor housing comprises at least one receiving-medium inlet for feeding the receiving medium into the reactor housing and wherein the method comprises the step of:

- feeding the receiving medium into the reactor housing through the receiving- ' medium inlet.

3. A method according to claim 1 or 2, further comprising the step of operating the shaft such the turbulence created by each carrier device constantly changes position relative to the carrier device.

4. A method according to any of the preceding claims, further comprising the steps of: - rotating the shaft in a first rotational direction, and subsequently

- rotating the shaft in a second opposite rotational direction.

5. A method according to any of the preceding claims, further comprising the steps of:

- rotating the shaft at a first velocity, and subsequently

-. rotating the shaft at a second velocity, the second velocity being different from the first velocity.

6. A method according to any of the preceding claims, wherein the step of rotating the shaft comprises the step of

- rotating the shaft with an rotational velocity that prevents the medium from

being ejected at least partly vertically from the carrier device.

7. A method according to any of the preceding claims, further comprising the step of adding a substance to the untreated medium during operation of the reactor.

8. A method according to claim 7, wherein the substance is a cleaning substance.

9. A method according to any of claims 7 and 8, wherein the substance is added at a point downstream the untreated-medium Inlet and upstream the treated-medium outlet.

10. A method according to any of the preceding claims, wherein the rotatable shaft extends in a generally horizontal direction.

11. A method according to any of the preceding claims, wherein the reactor housing comprises means for elevating or decreasing the temperature inside the reactor housing.