Gas-particle treatment device

Abstract

A gas-particle treatment device for bringing a particle stream into contact with a gas stream, comprising a chamber, at least one gas inlet for introducing gas into the chamber, the at least one gas inlet being such that the gas forms an accelerating gas stream and a main gas stream in the chamber, a particle feeder in fluid communication with a particle inlet for introducing the particle stream into the gas, a separator for separating the accelerating gas stream from the main gas stream in at least a part of the chamber, the separator being such that the accelerating gas stream has a higher average velocity than the main gas stream to form a curtain of the particle stream having an upstream edge and a downstream edge, and a particle outlet for receiving the curtain of the particle stream.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for treating particles using a gas.

[0002] The present invention relates in particular, but in no way exclusively, to a method and an apparatus for achieving one or more of heat transfer, mass transfer and chemical reaction between particles and a gas.

[0003] The present invention relates in particular, but in no way exclusively, to a method and an apparatus for drying particles using a gas stream.

[0004] The present invention also relates in particular, but in no way exclusively, to a method and an apparatus for coating and drying particles using a gas stream.

Background Art

[0005] Gas-particle treatment apparatuses such as fluidized beds have a wide range of applications ranging from fluid catalytic cracking, exhaust gas purification to ore roasting.

[0006] However, one problem faced by gas-particle processes is the insufficient distribution of the contact between the particle stream by the gas stream, resulting in a reduction in the overall heat transfer and / or mass transfer and / or interfacial reaction between the two streams. Other problems faced by gas-particle processes include the difficulty of accurately controlling either or both of the gas stream and the particle stream, and a large pressure drop.

[0007] Another drawback of fluidized bed and rotary drum type gas-particle treatment apparatuses is that they may damage the particles because they are exposed to mechanical stress and thermal stress for a long time.

[0008] Therefore, it is desirable to provide a gas-particle treatment apparatus with improved fluid and particle motion states.

Summary of the Invention

[0009] The Applicant has developed a method and an apparatus for supplying particles into a gas-particle treatment apparatus such that a gas stream and a particle stream interact to form one or more curtains of particles within the chamber of the gas-particle treatment apparatus. This method and apparatus are described in WO 2012 / 068631 pamphlet, which is incorporated herein by reference.

[0010] The particles enter the chamber from a supply opening and contact a substantially horizontal gas stream to form a curtain of particles. The trajectories of the particles consist of a horizontal component and a vertical component, and the flow region of the particles transitions as the particles pass through the top of the curtain. Due to the change in the particle flow situation, it becomes difficult to obtain a uniform distribution of the particles within the curtain for effective gas-particle contact. During the experiment, the Applicant observed that the particles at the upstream or leading edge of the curtain descend vertically rather than horizontally. Without being bound by theory, this observation was considered to be due to the inability of the gas stream to penetrate the particle curtain.

[0011] The particle curtain is thought to impede the horizontal flow of the gas stream. Instead of the gas at the top of the curtain following a horizontal streamline through the curtain, the top of the descending stream of particles functions as a barrier to the horizontal gas flow. This induces a downward flow of gas within the curtain as the gas bypasses and flows towards the more porous portions of the curtain and escapes downstream.

[0012] It has been found that the shape and size of the curtain are two factors that affect the heat transfer efficiency.

[0013] Through the study by the applicant, it has been found that the particle curtain is affected by forces such as the pressure gradient and the motion state of the induced flow, and the heat transfer and / or mass transfer and / or chemical reaction between the particle stream and the gas stream can be optimized by manipulating the shape and size of the curtain. Thereby, for example, the characteristics of the gas stream and the particle stream, such as the straightness of the gas flow, the higher effective surface area per unit volume of the particles in the curtain, and the particle residence time, and the interaction between these streams are improved.

[0014] The applicant plans to reduce the pneumatic transport behavior in which the particles begin to flow horizontally through the chamber in the direction of the main gas stream and increase the cross-flow contact between the gas and the particles.

[0015] Through further study by the applicant, it has also been recognized that since the accelerating gas stream can guide the particles to be introduced into the chamber at an angle with respect to the vertical, particularly using the accelerating gas, the accelerating gas stream can play an important role in maintaining the shape and size of the curtain and improving the heat transfer and / or mass transfer and / or chemical reaction. The accelerating gas can also keep the gas stream lines of both the accelerating gas and the main gas as vertical as possible and has the role of increasing the average sliding speed inside the curtain.

[0016] The present invention is a gas-particle treatment device for bringing a particle stream into contact with a gas stream, a chamber, at least one gas inlet for introducing a gas stream into the chamber, the gas forming an accelerating gas stream and a main gas stream in the chamber, at least one gas inlet; a particle feeder in fluid communication with a particle inlet for introducing a particle stream into the gas; a separator for separating the accelerating gas stream from the main gas stream in at least a part of the chamber, the accelerating gas stream having a higher average velocity than the main gas stream to form a curtain of the particle stream having an upstream edge and a downstream edge. A particle outlet for receiving a curtain of the particle stream, and A gas-particle treatment device is provided that includes

[0017] As used herein, the term "particle" includes, for example, solid and liquid particles in the form of droplets or thin sheets.

[0018] As used herein, the term "curtain" is understood herein to mean the region of the gas-particle contactor occupied by particles that fall due to the vertical component of the particle velocity when the particles contact the horizontal gas stream. The particle curtain tends to concentrate towards the downstream edge (rear edge) of the curtain with finer / smaller sized particles and towards the upstream edge (front edge) of the curtain with coarser / larger sized particles. Most (more than 50%) of the particles within the curtain can be collected at the particle outlet at the bottom of the treatment device.

[0019] As used herein, the term "separator" is understood herein to include any term such as a partition, tongue, flange, baffle, partition, etc. that functions as a tool to divide the entire gas flow into two gas flows.

[0020] The separator is disposed within the chamber to maintain different velocities of the accelerating gas stream and the main gas stream. The separator can separate the gas stream into an accelerating gas stream and a main gas stream having different velocities.

[0021] The separator may be disposed before and / or after the particle inlet.

[0022] The separator may be disposed upstream or downstream of the particle outlet. This separates the gas before contacting the re-introduced curtain of the particle stream or the curtain of new feed particles with the gas stream to form another curtain of particles having an upstream edge and a downstream edge.

[0023] The separator may be arranged to provide an acceleration gas zone having a height of at least 0.05 m, typically in the range of 0.05 to 1 m.

[0024] The separator may be arranged to provide a gap angle greater than 20°, typically in the range of 30 to 90°, more typically in the range of 70 to 90°, and even more typically in the range of 85 to 90°.

[0025] The gap angle is defined by the following formula.

Equation

[0026] The separator may have a solid construction. In this embodiment, the separator does not include holes that would allow fluid to flow through the separator.

[0027] The separator may have holes. In this embodiment, the holes allow fluid flow through the separator. Typically, the holes are sized to allow particles to pass through them. The holes may have a diameter of at least 0.1 mm, typically at least 1 mm, and more typically at least 10 mm.

[0028] The area of the holes may be at least 5% of the area of the separator. The area of the holes may be in the range of 20 to 80% of the area of the separator.

[0029] The applicant has found that by first guiding the particle stream into a first gas stream at a higher velocity before the particles enter a second gas stream at a lower velocity, the distribution of particles within the curtain is improved. Adopting this method of supplying particles to the gas stream, an increase in the distribution at the top of the descending particle stream is observed. Otherwise, the descending particle stream would act as a barrier to the horizontal gas flow, inducing a downward flow of the gas within the curtain as the gas would flow around and escape downstream towards the more porous portions of the curtain.

[0030] The gas can be introduced into the chamber using one gas inlet and divided into an accelerating gas stream and a main gas stream. Alternatively, a separate accelerating gas stream and main gas stream may be introduced into the chamber. Preferably, the accelerating gas stream is introduced into the region of the chamber above the separator, and the main gas stream is introduced into the region of the chamber below the separator.

[0031] The accelerating gas stream can flow through the upper region of the chamber.

[0032] The accelerating gas stream and the main gas stream may be introduced separately into the chamber.

[0033] The gas-particle treatment device may include a plurality of gas inlets and a plurality of particle inlets.

[0034] The gas-particle treatment device may include at least two pairs of particle inlets and particle outlets, and the first particle outlet is in fluid communication with the second particle inlet.

[0035] In one embodiment, at least two particle curtains are formed, a first curtain being formed between a first pair of particle inlets and particle outlets, and a second curtain being formed between a second pair of particle inlets and particle outlets. In other words, the second particle inlet reintroduces the first curtain into the chamber as the second curtain.

[0036] In another embodiment, the first and second particle inlets may not be arranged in a time series. For example, the first and second particle inlets may be arranged in a reverse cascade order in which the first particle inlet is located behind the second particle inlet. This may enable optimization of the force for moving the temperature / concentration.

[0037] The gas inlet and the particle inlet may be configured to introduce the gas stream and the particle stream in a cross-flow arrangement.

[0038] As used herein, the term "cross-flow" is understood herein to include contact between a particle stream and a gas stream in which the particle stream and the gas stream flow in different directions. This encompasses contact between the particle stream and the gas stream in the vertical and non-vertical directions as long as the particle stream and the gas stream do not move in the same direction.

[0039] At least one gas inlet may be arranged to introduce the gas substantially horizontally into the chamber.

[0040] The particle inlet may be configured to feed the particle stream substantially vertically into the gas stream. Typically, the particle inlet is arranged to feed the particle stream substantially downward into the gas stream. More typically, the particle inlet is arranged to feed the particle stream into an accelerating gas stream.

[0041] The particle stream may be introduced into the accelerating gas stream at an angle greater than 20 degrees formed between the particle stream and the horizontal component of the accelerating gas stream, this angle typically being in the range of 60 to 90 degrees and more typically in the range of 85 to 90 degrees.

[0042] The gas-particle treatment device may be configured to enable a bidirectional flow of either or both of the particle stream and the gas stream. Preferably, the gas-particle treatment device is configured to enable a bidirectional flow of the gas stream.

[0043] The gas-particle treatment device may be configured to enable a two-way cross-flow between the particle stream and the gas stream. This allows for contact between the particle curtain and gas streams from multiple successive directions.

[0044] In one example, the first horizontal gas stream is directed in a first direction that cross-flows with the particle curtain and subsequently in a second direction opposite to the first direction to change the direction of the particle curtain.

[0045] In this example, the two-way cross-flow system includes a cross-flow zone where the first horizontal gas stream contacts the particle curtain in the first direction.

[0046] The position of the separator within the cross-flow zone may be adjustable. Preferably, the height and length of the separator are adjustable.

[0047] The position of the separator between the cross-flow zones may be adjustable. Preferably, the height and length of the separator are adjustable.

[0048] In this example, each gas stream is separated into an accelerating gas stream and a main gas stream. Preferably, the gas stream is directed towards the separator to divide the gas stream into an accelerating gas stream and a main gas stream. The separator can maintain different velocities for the accelerating gas stream and the main gas stream along the length of the chamber.

[0049] The number of gas streams can determine the number of curtains formed within the chamber.

[0050] The accelerating gas stream may be located above the main gas stream.

[0051] The accelerating gas stream may be formed above the separator. As used herein, the term "above" is understood to include flowing at a height within a chamber that is higher than the height of the separator.

[0052] The main gas stream may be formed below the separator. As used herein, the term "below" is understood to include flowing at a height within a chamber that is lower than the height of the separator.

[0053] In one embodiment, the gas-particle treatment device comprises a horizontally disposed chamber. In this embodiment, the gas stream flows along the length of the chamber, the width of the particle curtain is defined by the width of the chamber, and the distance the particles fall is defined by the height of the chamber.

[0054] In a multi-stage operation involving the formation of a plurality of particle curtains within the gas-particle contactor, a separator may be disposed in front of each particle inlet. This allows the gas approaching each particle inlet to be separated into an accelerating gas stream and a main gas stream. This also enables the particles introduced into the contactor through each particle inlet to first contact the accelerating gas stream.

[0055] The gas-particle treatment device may be configured to improve the average slip velocity. The slip velocity is the magnitude of the relative velocity component of the gas with respect to the particles flowing in contact with each other. The slip velocity can be defined by the following equation, where the terms x, y, and z refer to the horizontal dimension (e.g., length), vertical dimension (e.g., height), and width dimension of the chamber.

[0056]

Equation

[0057] The gas-particle treatment device may be configured to achieve an average slip velocity that is at least 10% higher compared to a gas-particle treatment device without a separator. The average slip velocity is typically up to 15% higher, and more typically up to 26% higher.

[0058] The gas-particle treatment device may be configured to obtain the straightness of the gas flow after the first curtain. The straightness of the gas flow is evaluated by an effective height coefficient defined by the following formula.

[0059] Effective height coefficient = height of 90% of the main gas stream in the treatment area / height of the treatment area

[0060] The straightness of the gas flow is evaluated for the laminar gas flow of the main gas stream flowing in the direction along the length of the treatment device.

[0061] The effective height coefficient is the coefficient of the height at which 90% of the main gas stream is present within the treatment area.

[0062] Preferably, the effective height coefficient has a value greater than 0.50. More preferably, the effective height coefficient is in the range of 0.50 to 0.90.

[0063] The gas-particle treatment device may be configured such that less than 10% by weight of the particle stream contacts the separator, typically less than 7% by weight, and more typically less than 5% by weight.

[0064] One of the focuses of the present applicant is to develop a gas-particle treatment device that optimizes heat transfer and / or mass transfer between the gas stream and the particle stream in the treatment device, and it has been determined that the residence time of the particle stream in the gas-particle treatment device is an important factor affecting heat transfer and / or mass transfer.

[0065] Along with the average residence time of the particles in the gas-particle treatment device in any given situation, the effectiveness of heat transfer and / or mass transfer in the gas-particle treatment device can be governed by some factors including one or more of the following factors. · Sliding speed, · Particle volume velocity, · Velocity ratio, · Separator protrusion rate, and · Particle type.

[0066] For example, minimizing the volume velocity of the falling particle curtain can increase the residence time of the particles in the chamber and / or the total available surface area, and thus increase the effectiveness of heat transfer and / or mass transfer.

[0067] The effectiveness of heat transfer is evaluated as the ratio of the actual heat transfer between the gas stream and the particle stream to the maximum theoretical heat transfer between the gas stream and the particle stream. The effectiveness of mass transfer is evaluated as the ratio of the actual mass transfer of the species between the gas stream and the particle stream to the maximum theoretical mass transfer of the species.

[0068] The gas-particle treatment apparatus may be configured to obtain an average residence time in the range of 0.1 to 10 seconds for one pass of the particle stream.

[0069] The average residence time can be obtained by controlling the ratio of the separator protrusions in the chamber. The separator protrusion rate is defined by the following equation.

Equation

[0070] The average residence time may be controlled by designing the gas-particle treatment apparatus to have a desired gap angle.

[0071] To optimize the control of the contact between the particle stream and the gas stream, it is desirable to minimize the variation in particle residence time. Thereby, particle-related parameters such as particle temperature and particle dryness can be controlled more accurately. The variation in particle residence time can be evaluated using the dimensionless dispersion of the residence time.

[0072] The dimensionless dispersion of the residence time of the particles can be defined by any of the following equations.

Number

Number

[0073] The curtain of the particle stream can have at least a 5% reduction in the dimensionless dispersion of the residence time of the particles compared to the curtain of the particle stream formed in a gas-particle treatment device without a separator, typically at least a 10% reduction in the dimensionless dispersion of the residence time of the particles, more typically at least a 15% reduction in the dimensionless dispersion of the residence time of the particles, and even more typically at least a 20% reduction in the dimensionless dispersion of the residence time of the particles.

[0074] The curtain of the particle stream can have a dimensionless dispersion of the residence time of less than 0.00078 for ejectable particles defined by Geldart particle classification, typically less than 0.00070, more typically less than 0.00067, and even more typically less than 0.00065. Typically, the ejectable particles have an average diameter of at least 1 mm and a particle density of at least 1000 kg / m 3 of.

[0075] The applicant has recognized that the protrusion rate of the separator (related to the gap angle) is a factor that affects one or more of the residence time, the effective height coefficient (the straightness of the gas flow), and the maximum horizontal flight distance of the accelerating air.

[0076] A high protrusion rate of the separator means that the separator extends at least partially over the length of the particle inlet or feeder. This increases the total surface area of the curtain by increasing the trajectory of the curtain across the treatment device.

[0077] The straightness of the gas flow can be evaluated by the effective height coefficient of the particle curtain. By using a separator with a high protrusion rate and flowing the accelerating air as horizontally as possible, the straightness of the flow can be improved. The higher the protrusion rate, the more the influence of the accelerating air descending vertically upstream of the curtain can be reduced. C

[0078] The gas-particle treatment device may be configured to have a volumetric velocity in the range of 1 to 50 L / s / m 2 and preferably the volumetric velocity is in the range of 1 to 10 L / s / m 2 . The volumetric velocity is defined as the volumetric flow rate of the particles passing through the particle feeder divided by the footprint area of the feeder.

[0079] The volumetric velocity can be defined by the following formula, where m s is the mass flow rate of the particle stream, ρ s is the particle density of the particle stream, f l is the length of the particle feeder, A feed is the area of the particle feeder, V s is the volumetric flow rate of the particle stream, and W is the width of the chamber.

Number

[0080] At least 50% of the particles in the curtain may have a porosity defined by the volumetric velocity. Preferably, at least 60% of the particles in the curtain have a porosity defined by the volumetric velocity. More preferably, at least 80% of the particles in the curtain have a porosity defined by the volumetric velocity. Even more preferably, at least 90% of the particles in the curtain have a porosity defined by the volumetric velocity.

[0081] The chamber may comprise a treatment region having a height measured from the bottom of the treatment device to the separator.

[0082] The chamber may have a length exceeding its height. Preferably, the chamber is a horizontal duct. More preferably, the horizontal duct has a rectangular cross-section.

[0083] The chamber may comprise a plurality of modular components. Preferably, each module includes one particle inlet. More preferably, each module includes one particle outlet. Thereby, the gas-particle treatment apparatus can be expanded or reduced as needed by connecting or disconnecting the required number of modules.

[0084] The applicant has recognized that a bidirectional cross-flow modular system can enhance the compactness of a gas-particle treatment apparatus, particularly for higher contact ducts.

[0085] The bidirectional cross-flow modular system may include a single duct having a plurality of separators disposed at both ends of the duct. Preferably, the particles are introduced from the top of the duct and exit from the bottom of the duct. More preferably, the particles are introduced into the duct through an inlet located on the upper wall of the duct, and the particles exit the duct through an outlet located on the bottom wall of the duct. The bidirectional cross-flow modular system may include a multi-stage operation having a plurality of curtains.

[0086] The bidirectional cross-flow modular system may include using different gases for each cross-flow gas stream.

[0087] The bidirectional cross-flow modular system may include a permeable wall or honeycomb or mesh for separating the gas streams. This prevents or minimizes the interaction between the gas streams.

[0088] The gas-particle treatment apparatus may be configured to coat at least a portion of the particles in the particle stream with a coating. The coating may be in the form of a liquid and / or powder.

[0089] Suitably, the gas-particle treatment apparatus may include a particle coater for coating the particles with a coating. The particle coating apparatus may be integrated with the feeder apparatus of the treatment apparatus. Suitably, the particle coating apparatus may be a sprayer.

[0090] In some embodiments, the particles may be coated with a coating before entering the chamber. The coated particles can then be dried by a gas stream or reacted with a gas stream.

[0091] The particle feeder may be configured to introduce a substantially vertical particle stream into the gas stream. Typically, the particle feeder is configured to feed the particles downward into the gas stream.

[0092] The particle feeder may be configured to feed particles into the chamber to optimize the uniformity of the curtain formed within the chamber. Typically, the particle feeder is configured to feed particles into the chamber with a predetermined porosity.

[0093] The gas-particle treatment apparatus may be configured to form a curtain of particles in which at least 50% of the curtain has a porosity of at least 0.995. The particle feeder may be configured to feed particles into the chamber to form a curtain of particles, in which case at least 50% of the curtain has a porosity of at least 0.995.

[0094] The particle feeder may include a cassette configured to accept one or more properties of the particles, such as shape, size, surface morphology, to optimize the uniformity of the curtain formed within the chamber. Typically, the cassette includes a mesh that allows the particles to pass through and descend, minimizing particle aggregation or agglomeration. More typically, the cassette is removable and replaceable depending on the properties of the particles.

[0095] The particle feeder may be configured to control the flow rate of the particles fed into the chamber. Typically, the particle feeder includes one or more plates arranged at a predetermined interval from each other to achieve a desired flow rate.

[0096] The number of plates may be selected to improve the distribution of the particles fed into the chamber.

[0097] The particle feeder may be in fluid communication with one or more particle inlets for feeding the particles into the chamber. Preferably, the particle feeder is connected to one or more particle inlets for feeding the particles into the chamber.

[0098] The particle feeder may be configured to control either or both the volumetric flow rate and the mass flow rate of the particles fed to the particle inlet. Preferably, the particle feeder is connected to a transporter or a compressor to feed the particles to the particle inlet at a predetermined velocity.

[0099] The particle feeder or the particle inlet may include a mesh. The mesh can improve the distribution of the particles supplied into the chamber and reduce the agglomeration or lumping of the particles.

[0100] The particle feeder may have a length of at least 0.05 m, and the length typically ranges from 0.05 to 1 m.

[0101] The gas-particle treatment device may include a pressure driving device downstream of the particle feeder to draw in the accelerating gas through the top of the chamber and provide a pressure gradient to mitigate the induced vertical flow of the gas in the direction of the falling curtain of particles. The pressure driving device may be a fan, a blower, an injector, an eductor or a rectifier. In one embodiment, the pressure driving device is a barrel fan.

[0102] The downstream fan may be configured to allow a horizontal flow of gas through the leading edge first and then the trailing edge. The trailing edge of the curtain typically contains finer / smaller particles compared to the leading edge of the curtain, which typically contains the usually heavier coarser / larger particles. This ensures that the fan is effective in increasing the velocity of the accelerating gas and moderating the induced downward gas flow.

[0103] Increasing the accelerating gas flow can counteract the downward momentum transfer of the particles. By doing so, the gas flow profile can be made as horizontal as possible with respect to the general downward direction of the particles. Further, by enabling the accelerating gas profile to be maintained as horizontal as possible, the ability of the accelerating gas to push down the main gas stream is reduced, reducing the horizontal nature of the main gas. Also, vortex formation can be mitigated.

[0104] The present invention also provides a method of contacting a particle stream with a gas stream within a chamber, (i) introducing a gas stream into the chamber, at least a portion of the gas stream forming an accelerating gas stream and a main gas stream within the chamber, the accelerating gas stream having a higher average velocity than the main gas stream, (ii) introducing the particle stream into the gas stream to form a curtain of the particle stream having an upstream edge and a downstream edge, comprising.

[0105] Preferably, the method comprises contacting the particle stream with the gas stream using the aforementioned gas-particle treatment apparatus.

[0106] The term "contacting" is understood herein to include drying or reacting the particles using the gas stream.

[0107] The method may include introducing the gas stream into the chamber in a substantially horizontal direction.

[0108] The method may include directing a gas stream toward a channel bounded by a separator at its lower edge such that an accelerated gas stream is formed above the separator.

[0109] The method may include directing a gas stream toward a channel bounded by a separator at its lower edge to maintain a different velocity between the accelerated gas stream and the main gas stream.

[0110] The method may include controlling the main gas stream and the accelerated gas stream at a velocity ratio in the range of 1 to 10, preferably in the range of 1 to 6, more preferably in the range of 1 to 3.

[0111] The velocity ratio is defined as the ratio of the velocity of the accelerated gas stream to the velocity of the main gas stream. The method may include introducing a plurality of gas streams into the chamber. Preferably, the method includes introducing a plurality of gas streams into the chamber in opposite directions to each other. More preferably, the method includes controlling the direction of the gas streams such that the directions of the gas streams alternate along the height of the chamber.

[0112] The method may include directing a plurality of gas streams toward respective separators, thereby forming a plurality of pairs of an accelerated gas stream and a main gas stream.

[0113] The method may include controlling one or more of the gas stream velocity, the particle stream velocity, the position and size of the separator, and the dimensions of the chamber such that the dimensionless dispersion of the particle residence time is reduced by at least 5% compared to the curtain of the particle stream formed in a gas-particle treatment apparatus without a separator.

[0114] The method may include introducing a substantially vertical particle stream into a gas stream. The method may include introducing the particle stream into an accelerating gas stream. Typically, the method includes introducing the particle stream in a crossflow with the accelerating gas stream. Maintaining a horizontal accelerating gas stream is thought to maximize the total surface area of the curtain exposed to the gas stream.

[0115] The method may include controlling the velocities of the main gas stream and the accelerating gas stream to improve momentum transfer from the gas stream to the particle stream.

[0116] The method may include introducing the particle stream into a gas stream at an angle greater than 20 degrees between the particle stream and the horizontal component of the gas stream, the angle typically being in the range of 60 to 90 degrees, more typically in the range of 85 to 90 degrees.

[0117] The method may include maintaining the atmospheric pressure within the chamber.

[0118] The method may include maintaining a pressure within the chamber equal to the pressure of the source of the particle stream.

[0119] The method may include introducing a positive pressure into the accelerating gas stream and increasing the velocity of the accelerating gas stream.

[0120] The method may include using a pressure driving device downstream of the inlet of the particle stream to draw accelerating air through the top of the chamber. The pressure driving device may be a fan, blower, injector, eductor or rectifier.

[0121] The method may include maintaining a curtain of particles, in which case at least 50% of the curtain has a porosity of at least 0.995. The porosity is based on a volumetric velocity of the curtain of 1 to 50 L / s / m 2can be maintained by controlling within the range. Thereby, a significant proportion of the particles in the particle stream can be prevented from being hindered by adjacent particles in the particle stream.

[0122] The volumetric velocity is defined by the following equation, where m s is the mass flow rate of the particle stream, ρ s is the particle density of the particle stream, f l is the length of the particle feeder, A feed is the area of the particle feeder, V s is the volumetric flow rate of the particle stream, and W is the width of the chamber.

Number

[0123] The method may include coating at least a portion of the particles of the particle stream.

[0124] The coating may be in the form of a liquid and / or a powder.

[0125] The method may include coating the particles with a coating using a particle coating device.

[0126] The particle coating device may be a sprayer.

[0127] The method may include coating the particles with a coating before entering the chamber.

[0128] The method may include forming a processing region having a height equal to the height of the separator, measured from the bottom of the chamber to the separator.

[0129] The method may include obtaining the straightness of the gas flow after the first curtain. The straightness of the gas flow is evaluated by an effective height coefficient defined by the following equation. Effective height coefficient = height of 90% of the main gas stream within the treatment area / height of the treatment area

[0130] The effective height coefficient may have a value greater than 0.50, and preferably has a value of 0.5 to 0.9.

[0131] The method may include controlling one or more of the gas stream velocity, the particle stream velocity, the position and size of the separator, and the chamber dimensions such that less than 10% by weight of the particle stream contacts the separator.

[0132] The method may include obtaining an average residence time in the range of 0.1 to 10 seconds.

[0133] The average residence time can be achieved by controlling the separator protrusion rate and any one or more of the particle volume velocity, the velocity ratio, and the particle type. The separator protrusion rate may be up to 100%, and is typically in the range from 25% to less than 100%.

[0134] The particle size may be in the range of 50 to 10,000 microns. The Applicant has observed that particles having a size less than 50 microns may experience problems with particle agglomeration. For these particles, when the surface area per kilogram of particles increases compared to larger particles (e.g., larger than 10,000 microns), the straightness of the flow of the main gas stream behind the curtain in a multi-stage system may be significantly inhibited.

[0135] This is because larger particles are too heavy and may fall extremely fast through the main gas stream for effective cross-flow to occur. The ratio of the cross-sectional height to the width of the chamber may be 1 or more. The residence time of the falling particles can be increased by maximizing the falling height of the particles across the cross-section of the chamber. The ratio of the cross-sectional height to the width may be less than 1 to increase the width of the chamber and the amount of feed material introduced into the chamber while increasing the residence time using one or more other parameters such as volumetric velocity, velocity ratio, separator protrusion rate, and particle type.

[0136] The present invention will be further described by way of example only with reference to the accompanying drawings.

Brief Description of the Drawings

[0137]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Figure 31

Figure 32

Figure 33

Figure 34

Figure 35

Figure 36

Figure 37

Figure 38

Figure 39

Figure 40

Figure 41

Figure 42

Figure 43

Figure 44

Figure 45

Figure 46

Figure 47

Figure 48

Figure 49

Figure 50

Mode for Carrying Out the Invention

[0138] One form of the gas-particle treatment apparatus is shown in FIGS. 1 and 2. The treatment apparatus 10 includes a chamber 12 having a first end 14, an opposite second end 16, an upper wall 18 and a bottom wall 20, and the upper wall 18 and the bottom wall 20 extend between the first end and the second end. The second end is located on the opposite side of the first end, and the side wall portion extends substantially horizontally so as to define a horizontally oriented chamber. A separator in the form of a tongue 22 extends from the first end 14 of the chamber.

[0139] The chamber 12 has a series of particle inlets 24 through which particles are introduced into the chamber. Solid particles can be supplied to each inlet by any type of particle feeder. The feeder may be configured to introduce the particles into the chamber such that the particles fall or are accelerated by the acceleration due to gravity into the chamber. The inlet or feeder may include a screen, sieve, grate, lattice, etc., through which the particles are introduced into the chamber. Preferably, the screen, sieve, grate or lattice is provided in embodiments where the particles are introduced into the chamber by free fall (i.e., by gravity). The purpose of the screen, sieve, grate or lattice is to reduce particle agglomeration or lumping, to evenly distribute the particle stream across the feeder or the entire particle inlet before the particles are introduced into the chamber, and to set the mass flow rate of the particles.

[0140] The particle inlets 24 are arranged on the upper wall 18 of the chamber. The outlet of the feeder communicates with and / or coexists with the particle inlets 24. The treatment apparatus is configured and operated such that the particles supplied through each particle inlet generate a stream of separate, individual particles that flow from the upper wall to the bottom wall portion.

[0141] FIG. 10 shows one embodiment of a particle feeder 200 including a housing 210 having a particle inlet 24. A cassette 212 (see FIG. 9) is disposed at the particle inlet 24.

[0142] The cassette 212 comprises a plurality of right-angled bent plates 214 spaced according to the desired flow rate of particles at the associated particle size and distribution. The number of plates is configured to produce a uniform distribution of particles descending under gravity, and the total spacing of the particle inlet 24 produces the horizontal dimension of the curtain of particles.

[0143] The spacing between the plates is thought to provide maximum resistance to the particles as they slide towards the right-angled bends before descending vertically, such that the particles can pass horizontally through the spacing and then descend vertically rather than the lateral vibration of the particle feeder housing 210 (on and around which the particles are). Thus, the flow rate for a particular particle size and distribution is controlled by the spacing of the plates with respect to the particle size and shape and the vibration (frequency and amplitude) of the feeder housing 210. The right-angled bent plates 214 are designed to prevent the funneling of the particle stream towards the center of the horizontal dimension by creating different horizontal distances for the particles to travel and thus producing a uniform distribution of particles flowing vertically.

[0144] The chamber 12 also has a series of particle outlets 26 through which the particles exit the chamber. The particle outlets are formed in the bottom wall 20 on the side opposite to where the inlets are located. The particle outlets 26 are on the opposite side of each particle inlet 24 but offset from each particle inlet. Each outlet is disposed downstream of its respective inlet due to some horizontal movement of the particles as they travel through the chamber. The individual particle streams flowing from each particle inlet 24 exit the chamber through a particular particle outlet. For example, the particles flowing from the first particle inlet 24 exit the chamber only through the first particle outlet 26.

[0145] In the first particle curtain state as shown in FIG. 1, the particle outlet 26 is disposed on the bottom wall 20 on the opposite side where the particle inlet 24 is disposed. In the second curtain state as shown in FIG. 2, the particle inlet 25 is disposed on the upper wall 18 of the chamber 12. Particles are introduced into the chamber through the particle inlet 25 and are induced to flow not vertically but rather substantially horizontally as compared to FIG. 1.

[0146] As the particles descend through the gas in the processing apparatus 10, heat exchange and / or mass exchange and / or chemical reactions occur between the particle stream and the gas stream. At any point in the chamber 12, the particle streams in the chamber do not substantially mix.

[0147] Since the processing apparatus can operate with a plurality of individual particle streams, it can function as a “multi-stage” processing apparatus. The multi-stage processing apparatus can be configured to receive two or more new feeds. The multi-stage processing apparatus may include a plurality of particle inlets and outlets, with each particle inlet paired with a dedicated outlet, which provides the advantage of reducing space and cost requirements compared to having a plurality of processing apparatuses to perform the same number of single particle stream processes.

[0148] A series of particle inlets and a series of particle outlets can be configured to recirculate particles through the chamber 12. In one form, this recirculation can be from each outlet to its respective inlet. In another embodiment, the first particle outlet 46 is connected to the second particle inlet 48 via a conduit and the second particle outlet 50 is connected to the third particle inlet 52 via another conduit such that particles flow between the connected outlet and inlet. One form of this embodiment is shown in FIG. 5. In this embodiment, the first particle inlet 44 defines the initial supply of particles to the chamber 12 and the third particle outlet 54 defines the final outlet for particles to exit the chamber 12 and the processing apparatus. In a variant, the system may be semi-closed such that some of the particles exit the processing apparatus at the third particle outlet, but particles are added and recirculated to the first particle inlet to replenish the particles that have exited the system.

[0149] As shown in FIG. 11, a chamber 95 also includes a main gas inlet 100 disposed at a first end 97 of the chamber 95 and a gas outlet 118 disposed at a second end 99, whereby gas flows along the length of the chamber between the inlet and the outlet during operation of the processing apparatus 10. To effect and direct this gas flow, the processing apparatus 10 may include a main gas feeder 98 that supplies gas to the main gas inlet 100 of the chamber. The gas feeder may be in the form of a pump, compressor, blower, or the like. The chamber also includes an acceleration gas inlet 106. The processing apparatus may include an acceleration gas feeder 104 that can be in the form of a fan for supplying acceleration gas 102. The acceleration gas stream and the main gas stream are separated within the chamber 95 by a tongue 108. Solid particles are delivered from a hopper 110 to a particle inlet 112 of the chamber. Each particle outlet 114 of the chamber is connected to a hopper 116 to capture the exiting particle stream. The main gas stream exits the chamber at the gas outlet 118. The processing apparatus may include an additional hopper 120 downstream of the chamber for collecting residual particles in the outlet gas and a suction fan 122 for directing the gas flow.

[0150] It is understood that the processing apparatus may include more or fewer particle inlets and outlets. In one variation, the processing apparatus may include a single particle outlet formed at the bottom of the chamber that accepts all particles entering the chamber through the inlet.

[0151] Another form of the gas-particle processing apparatus is shown in FIG. 3, where a plurality of tongues 28 are disposed within the chamber and upstream and downstream of particle inlets 30 and 32. Gas can be introduced into the chamber as a single stream using one gas inlet and then split into an acceleration gas stream and a main gas stream using a separator, or separate acceleration and main gas streams can be introduced into the chamber using dedicated gas inlets.

[0152] One advantage of having an acceleration gas stream that is faster than the main gas stream is that heat transfer and / or mass transfer can be optimized by maximizing the slip velocity. This can be achieved by controlling the stream profiles of the acceleration gas and the main gas to be as horizontal as possible, as can be seen from the following equation, where the Y slip term makes the most important contribution to the slip velocity.

Number

[0153] Two curtains are formed within the chamber of the processing apparatus. FIG. 50 shows the leading and trailing edges of the particle curtain. The particles within the first curtain exit the chamber at particle exit 31. The particles exiting the second curtain at particle exit 33 can be recycled and reintroduced into the chamber and the first curtain at particle inlet 30. The presence of the plurality of tongues reduces the downward force on the main gas stream 34. This enables a majority of the main gas stream to maintain an effective height coefficient, for example, as compared to FIG. 1. In another embodiment, the pressure gradient along the path of the acceleration gas stream can be maintained by inserting one or more fans, blowers, eductors, straighteners, or other pressure driving devices adjacent to the plurality of tongues.

[0154] Upstream and downstream tongues, combined with the use of a fan, blower, rectifier, or other pressure-driven device to increase the accelerated gas flow rate, help reduce the downward drag force imparted by the particles on the accelerated gas and main gas stream profiles.

[0155] The Applicant has found that it is impossible to re-accelerate the bulk gas flow rate without the upstream and downstream tongues. The Applicant has also performed simulations showing that in some situations, the total gas flow required for the curtain with tongues to reach the same location as without tongues is approximately 50% less.

[0156] Figures 4 - 7 show further forms of the gas-particle treatment apparatus including a spray booth 36 that coats solid particles with a liquid layer before the particles are introduced into the chamber. Depending on the desired final form of the particles, the coated particles can be dried or reacted using a gas. In these figures, moisture is removed from the particles into the gas stream to form a wet effluent gas stream.

[0157] Figure 4 shows a cross-flow contact configuration for drying the wet film coating on the particles. This configuration involves both heat and mass transfer due to heating and evaporation of the coating and heating of the particles.

[0158] Particles are supplied to the spray booth 36 where the nozzles spray droplets onto the individual particles to form a uniform film coat on each particle. As the wet coated particles exit the spray booth 36, they enter the chamber 12. Horizontal drying gas 40 is supplied to the chamber 12. The horizontal drying gas includes an accelerating gas stream and a main gas stream. Each of these gas streams can be introduced into the chamber separately or formed within the chamber using the separator 28. First, the coated particles contact an accelerating gas that provides horizontal acceleration to the particles. The particles then descend into the main gas stream where most of the drying takes place. The coating on each particle is dried so that the particles do not agglomerate or deform at the particle outlet 38. Various coatings have various drying requirements to reach an acceptable drying level in that coating. The film coating on each particle allows for rapid drying of the moisture in the coating within the time it takes for the particle to pass through the processing apparatus.

[0159] The residence time of each particle is important to determine the time the wet coated particles must contact the hot gas to dry to the extent necessary to avoid agglomeration or deformation, according to the drying kinetics of the coating. As a result of the mass transfer of water from the coating to the horizontal drying gas, the drying gas removes moisture from the coating. The relative humidity in the exit gas (moist gas 42) varies according to the mass fraction of water in the exit gas and the exit temperature. Excess moisture in the exit gas is removed downstream of the curtain. The excess moisture may be removed, recycled or integrated within the gas particle process for heat recovery. The resulting dried gas may be recycled and used as the inlet gas stream to dry the first curtain, forming a closed loop.

[0160] Figure 5 shows an embodiment of Figure 4 optimized such that a greater throughput of particles is achieved for the same flow of horizontal drying gas 40. In this embodiment, the particles can be dried in n consecutive layers within the same duct. In use, the particles enter the spray booth 36 for coating the particles and then enter the chamber 12 through the first particle inlet 44 to form a particle curtain. Water evaporates from the coating of the particles within this curtain to a predetermined level, and the particles exit through the first particle outlet 46. The particles are then directed to another spray booth 36 for a second coating. The coated particles then enter the second particle inlet 48 where they form a second particle curtain in which the second coating is dried. The second particle curtain exits the chamber through the second particle outlet 50 and is directed to another spray booth 36. The coating process is repeated to form a third coating on the particles before they re-enter the chamber through the third particle inlet 52. The particles are dried within the chamber and exit through the particle outlet 54, producing particles having a three-layer coating.

[0161] The advantageous effects of this configuration include: i) better utilization of the energy required to heat the gas to the temperature required for drying (higher particle throughput per kWh consumed), ii) a more compact design since this configuration requires only one duct to dry multiple layers, iii) quality control of each layer ensures that each coating layer is dried before proceeding to the next coating and drying stage, and iv) the operability of the coating drying kinetics results in an optimized process for quality-controlled products versus energy consumption.

[0162] In another embodiment shown in FIG. 6, the multi-stage system of FIG. 5 operates as a continuous process where each coating stage is carried out in a separate duct that coats and dries each layer of the coating. Similar to the embodiment of FIG. 5, the particle outlet of the previous stage becomes the particle inlet of the next coating stage. However, in this embodiment, the ducts are stacked vertically to allow gravity to accelerate the particles through successive stages. A first stream of horizontal drying gas 41 is directed into the first duct 19. The horizontal drying gas 41 forms an accelerating gas stream and a main gas stream within the chamber, and within the chamber, both streams are separated by a separator. The particles enter the spray booth 36 and are coated with a layer before entering the chamber through the particle inlet 56. The gas stream removes water from the coating such that the effluent gas (moist gas stream 43) contains a certain mass fraction of moisture from the coating. The coated particles exit the first duct through the particle outlet 58 and are directed to another spray booth 36. The moist-coated particles then exiting the spray booth enter the second duct 21 through the particle inlet 60, and the second coating is dried using the horizontal drying gas stream 45. The particles having the dried second coating exit the duct through the particle outlet 62 and enter another spray booth for the third coating. The moist-coated particles enter the third duct 23 through the particle inlet 64, where the third coating layer is dried using the horizontal drying gas 49. The dried particles exit the third duct through the particle outlet 66 to form the final product.

[0163] The advantageous effects of such an embodiment are that since each coating is present in a different duct, contamination is less likely to occur. On the other hand, such a system is not more compact and requires a higher capital cost for the same throughput of particles (e.g., higher capital cost of fans and energy consumption). An alternative multi-stage embodiment for the embodiment of FIG. 5 is shown in FIG. 7. Three consecutive coating and drying stages operate in a single chamber or duct as a continuous process. The horizontal drying gas flows through chamber 12 having three particle inlets. As the gas moves horizontally across the chamber, it becomes cooler and more humid. The solid particles are coated in spray booth 36 and then enter the chamber through particle inlet 68 furthest from the inlet of the horizontal drying gas. The coated particles interact with the gas that is coolest and has the highest moisture content and are dried. The particles from the first particle outlet 70 are directed to another spray booth and coated. The coated particles enter the chamber at a second particle inlet 72 that is between the inlet of the horizontal drying gas stream and the first particle inlet 68. The coated particles are dried using the horizontal drying gas stream and exit the chamber at particle outlet 74. The particles at particle outlet 74 are directed to another spray booth for a third coating. The coated particles enter the chamber at a third particle inlet 76 and interact with the horizontal drying gas stream when it is hottest and drying. The particles having a three-layer coating layer are dried and sent out at a third particle outlet 78 to produce the final product. This system is optimized for forces that move temperature and concentration. However, the system may be configured to control the relative humidity that may interfere with effective drying in later curtains.

[0164] During operation, the gas flows through chamber 12 in a substantially straight streamline (first) velocity in the horizontal direction.

[0165] As shown in FIG. 1, the gas stream 13 is directed towards the tongue portion 22 such that the gas stream is separated into an accelerating gas stream 15 and a main gas stream 17. The ratio of the accelerating gas stream velocity to the main gas stream velocity is in the range of 1 to 6. It is considered that vortices are formed in the space above and inside the processing region of the processing device. The processing region is defined as the region occupied by the main gas stream between the bottom and the tongue portion of the processing device.

[0166] Each stream of particles is introduced into the chamber at a second velocity and a supply angle with respect to the direction of the streamline velocity of the gas stream.

[0167] The gas and each particle stream have respective first and second mass flow rates through the chamber. Preferably, during operation of the processing device, one or both of these mass flow rates are controlled to obtain desired particle curtain characteristics such as the straight-through line of the gas flow, the porosity, the effective surface area per unit volume of the particles in the curtain, and the particle residence time.

[0168] The gas-particle processing device may have a plurality of inlets for introducing a plurality of particle streams into the chamber and respective outlets. Each particle stream may have a different mass flow rate and / or different types of particles.

[0169] It is important that a significant portion of the particles contained in the particle stream are not hindered by adjacent particles in the particle stream. The resulting increase in the approach of the gas to the particle surface improves heat transfer and / or mass transfer and / or chemical reactions, for example, to promote drying of the particles in the particle stream.

[0170] Another embodiment of the present invention is shown in FIG. 8. The first tongue portion 90 is disposed within the chamber at the inlet of the streams of the accelerating air 82 and the main air 84. A plurality of tongue portions 92, 94 are disposed downstream, side by side with the first tongue portion 90. The plurality of barrel fans 88 are disposed adjacent to the particle inlets 86 and 87. In this embodiment, the fan 88 generates a suction force that pulls the accelerating air stream through the first curtain so that the accelerating air stream is directed horizontally to the downstream tongue portion 92. Instead of the accelerating air stream that descends vertically when the particles interact with the main air stream, the "pull" of the accelerating air stream using the fan forms a well-distributed particle curtain. This also maintains the accelerating air stream characteristics of the downstream curtain because the volumetric flow rate of the accelerating air stream can be maintained by the fan.

[0171] Another embodiment of the present invention is shown in FIG. 29. Particles are introduced into the duct of the modular unit through a particle inlet disposed in the upper wall of the duct. The first horizontal cross-flow gas stream is separated into an accelerating gas 1 and a main gas 1. The accelerating gas 1 enters the duct from an inlet disposed at the first end of the duct in the region above the first tongue or partition. The main gas 1 enters the duct from an inlet disposed at the first end of the duct in the region below the first partition. The particles are introduced into the accelerating gas stream 1 through the particle inlet. The particles then descend through the gap of the first partition and are introduced into the main gas 1 that forms a particle curtain. The main gas 1 and the accelerating gas 1 exit the duct through a gas outlet 1 disposed at the second end of the duct opposite the first end of the duct.

[0172] The second horizontal cross-flow gas stream is introduced into the duct from an inlet disposed at the second end of the duct in a direction opposite to that of the first cross-flow stream. The second cross-flow gas stream is separated into an accelerating gas 2 and a main gas 2. The accelerating gas 2 enters the duct through a flow path formed by the second partition wall and the third partition wall. The main gas 2 enters the duct in the region below the third partition wall. The curtain is introduced into the accelerating gas 2 through a gap in the second partition wall that changes the direction of the curtain in the opposite direction. Then, the curtain is introduced into the main gas 2 from the gap in the third partition wall. The particles of the curtain exit the duct from a particle outlet disposed at the bottom end of the duct. The main gas 2 and the accelerating gas 2 exit the duct from an outlet disposed at the first end of the duct. The partition walls serve to prevent the flow of each horizontal cross-flow gas stream from leaking into another adjacent gas stream. Pressure balance is necessary to equalize the gas pressure through the vertical path of the descending particles. The accelerating gas provides a momentum transfer that shifts the particle flow in the opposite direction as the particles move from the influence of one gas stream to another. The accelerating gas also keeps the overall gas flow horizontal (attenuating the induced vertical flow).

[0173] Another embodiment of the present invention with respect to the embodiment of FIG. 29 is shown in FIG. 30. To further suppress the interaction of the separate cross-flow gas streams with each other, a permeable wall or honeycomb or mesh can be used to cover the gap between the partition walls, allowing the particles to pass through but suppressing the vertical gas turbulence that can promote the passage of the gas through another cross-flow gas stream below. This type of system is suitable for non-agglomerating particles and particles that are not susceptible to mechanical stress.

[0174] FIG. 35 is a schematic view showing the gap angle between the separator and the particle inlet, and provides equations defining the gap angle and the separator protrusion rate.

[0175] Experimental work Experiment 1 The experimental work related to the present invention was carried out by the applicant to demonstrate that the present invention can obtain a high surface area of the curtain and improve the straightness of the gas flow in the gas-particle treatment device.

[0176] The applicant carried out the following two-stage experimental work. i) A physical experimental program for a pilot plant that generated a VIPAC-certified dataset forming the basis of a physically verified CFD model, and ii) A virtual experimental program for testing the influence of accelerated air, a separator, and the protrusion of the separator.

[0177] The details of the physical experimental work are summarized below.

[0178] i. The experiment was conducted in a physical pilot plant consisting of horizontal contact using accelerated gas, main gas, and a partition for separation.

[0179] i. The experiment included sensible heat transfer applications involving a stream of hot air as the total gas stream and a stream of silica sand particles as the particle stream.

[0180] ii. The gas-particle treatment device operated as a horizontal duct with a height of 0.5 m and a width of 0.5 m. The height of the accelerated gas was 0.05 m.

[0181] iii. The mass flow rate of the total gas stream, including the accelerated air flow and the main gas flow, was kept constant at about 0.4 kg / s. The inlet temperature of the total gas was kept constant at 132 °C.

[0182] iv. The mass flow rate of the particle stream was kept constant at about 0.5 kg / s.

[0183] v. Each experiment was carried out over a steady-state period of 40 - 45 minutes.

[0184] vi. The accelerating air height was defined as the height above the separator to which the accelerating air was supplied. In the experiment, the accelerating air height was 0.05 m.

[0185] vii. The separator protrusion rate (%) = 0 was kept constant.

[0186] viii. The experiment was conducted for three different speed ratios.

[0187] ix. The heat load and heat transfer efficiency were measured for each experiment.

[0188] x. The experiment was conducted on a gas-particle treatment device having only one curtain.

[0189] xi. Next, each experiment was simulated using computational fluid dynamics (CFD) modeling software. The CFD simulation was able to predict the experimental results to an acceptable level that verified the modeling work.

[0190] The details of the virtual experimental work are summarized below.

[0191] i. The experiment was conducted using computational fluid dynamics (CFD) modeling software verified using the results of physical experiments in a pilot plant.

[0192] ii. The CFD modeling software simulated a specific sensible heat transfer application including a stream of hot air as the total gas stream and a stream of soda ash particles as the particle stream.

[0193] iii. The gas-particle treatment device was modeled as a horizontal duct 1.003 m in height and 0.5 m in width.

[0194] iv. The mass flow rate of the total gas stream including the accelerating air flow and the main air flow was kept constant at 1.13 kg / s.

[0195] v. The mass flow rates of the accelerating air and the main air were kept constant.

[0196] iii. The mass flow rate of the particle stream was kept constant at 1 kg / s.

[0197] vii. The accelerating air height was defined as the height above the separator to which the accelerating air was supplied.

[0198] viii. The separator protrusion rate was calculated using the following equation.

Equation

[0199] x. The change in the accelerating air height changed the velocity ratio between the accelerating air and the main air. xi. One simulation was performed without a separator. The other simulations were performed at accelerating air heights of 50 mm, 75 mm, 100 mm, and 200 mm, and accelerating air velocities of 16 m / s, 10.67 m / s, 8 m / s, and 4 m / s, respectively. xii. Experiments were performed on a gas-particle treatment device having only one curtain. xiii. The process parameters of the simulations are shown in Table 1 below.

Table 1

[0200] Experiment 2 The experimental work related to the present invention was carried out by the applicant to demonstrate that the compactness of the present invention can be improved using a two-way cross-flow system.

[0201] The details of the experimental work are summarized below.

[0202] I. The experiments were performed using computational fluid dynamics (CFD) modeling software.

[0203] II. The CFD modeling software simulated a specific sensible heat transfer application that included a stream of hot air as the total gas stream and a stream of seed particles as the particle stream.

[0204] III. The gas-particle treatment device was modeled as a single duct that was 5 m high, 1 m long, and 0.15 m wide.

[0205] IV. The duct was separated into two cross-flow sections, each 2.5 m high.

[0206] V. The accelerated air height was defined as the height above the separator where the accelerated air was supplied.

[0207] VI. The mass flow rate of the particle stream was kept constant at 0.3 kg / s.

[0208] VII. The process parameters of the simulation are shown in Table 2 below.

Table 2

[0209] The experimental work related to the present invention was carried out by the applicant to demonstrate the performance differences resulting from using a separator and a pressure driving device in a contactor that forms a single particle curtain.

[0210] The simulation uses Persian clover seeds that are 0.881 mm in diameter and uniform at 15 °C and interact with air at 15 °C. The process parameters of Experiment 3 are shown in Table 3 below.

Table 3

[0211] For the simulations without a separator and with a separator, the same bulk air flow is used, and for the simulation with a separator, the same total flow rate is simply distributed to two individual inlet gas flows. Isothermal application was performed to minimize the resulting meandering due to heat transfer, i.e., gas cooling and deceleration.

[0212] Experiment 4 The experimental work related to the present invention was carried out by the applicant to demonstrate the performance differences resulting from using a plurality of separators and pressure driving devices in a contactor that forms a plurality of particle curtains.

[0213] The simulation interacts air at 15 °C with two curtains consisting of seeds of 2 mm at 15 °C in a multi-stage system having the characteristics described in Table 9 below.

[0214]

Table 4

[0215] Both curtains have separators on the upstream and downstream sides and a pressure driving device (fan) on the downstream side.

[0216] Experimental results Experiment 1 In this CFD study, the influence of the separator protrusion amount on several process parameters including the heat load was investigated. In this study, the gap angle encapsulating the separator protrusion amount and the height of the acceleration zone is inversely proportional to the separator protrusion amount for a constant acceleration gas height and feeder length.

[0217] The CFD simulation of the gas-particle treatment device without a separator included a stream of soda ash particles as a particle stream introduced into the hot air gas stream. A separator that separates the gas flow into accelerating air and main air was not provided. Referring to FIG. 12, since the gas flow was induced vertically, the gas flow did not effectively move the curtain horizontally. As a result, the particles moved slightly horizontally and the curtain did not spread well.

[0218] Despite having the same thermal inlet characteristics for both the air flow and the particle flow, heat exchange was clearly highest where the separator protrusion amount was maximum for all four accelerating air heights.

[0219] The experimental results indicate that a higher separator protrusion rate extended the trajectory of the curtain, which made the total surface area of the curtain larger.

[0220] A higher separator protrusion rate also ensured that the accelerating air remained horizontal as much as possible, which means that instead of the accelerating air becoming a "nose-diving" flow and avoiding the curtain portion, the total surface area of the curtain was utilized. The nose-diving effect enables the accelerating air to descend through the gap between the separator and the curtain.

[0221] The recorded maximum heat load was for the example of an accelerated air height of 75 mm and a protrusion rate of 100%, which enabled the main air to be made slightly higher than in the examples of an accelerated air height of 100 mm and 200 mm (see Tables 3 - 5 below). The graph of heat load versus protrusion rate for the CFD example in Figure 24 shows that the heat load of the processing device increased proportionally to the protrusion rate for all four examples of accelerated air height. The heat load at a protrusion rate of 0% was highest at an accelerated air height of 50 mm. The lowest heat load at a protrusion rate of 0% was observed at an accelerated height of 100 mm. However, at higher protrusion rates, it can be seen from Figure 24 that the lowest heat load was for the example of an accelerated air height of 200 mm. At a protrusion rate of 60%, the example with an accelerated air height of 75 mm had the highest heat load of 65000 W, and the second highest heat load for the example with an accelerated air height of 100 mm was approximately 64300 W. The lowest heat load at a protrusion rate of 60% was for the example of an accelerated air height of 200 mm. At a protrusion rate of 100%, the heat load for the example with an accelerated air height of 75 mm was approximately 67860 W, and the heat load at an accelerated air height of 100 mm was 66700 W. This demonstrates that the protruding separator is a beneficial feature.

[0222]

Table 5

[0223]

Table 6

[0224]

Table 7

[0225] The experimental results show that the average residence time is maximized as the ratio of the separator protrusion increases. Refer to Tables 3 to 5. This may be related to the mitigation of the nose-dive effect. The acceleration air tends to nose-dive, which particularly affects the y-component of the velocity at the leading edge of the curtain. The standard deviation of the residence time also increased with a larger separator protrusion, but it was still about 5% of the residence time.

[0226] Figure 25 shows a graph of the average residence time for various protrusion rates for examples of CFD at acceleration air heights of 50 mm, 75 mm, 100 mm, and 200 mm without a separator. The graph shows that at a protrusion rate of 0%, the average residence time of the particles is highest in the example without a separator. This could be because without a separator and acceleration air, the particles in the particle stream are not accelerated as they descend through the gas flow. The second-highest average residence time at a protrusion rate of 0% can be seen in the example of an acceleration air height of 50 mm. The average residence time at a protrusion rate of 0% was the lowest in the example of an acceleration air height of 100 mm. As the protrusion rate increased, the average residence time at the four acceleration air heights also increased. At a protrusion rate of 60%, the highest average residence time can be seen at 75 mm, the second-highest at 100 mm, and the lowest at 200 mm. The highest average residence time can be seen on the graph at a protrusion rate of 100% for the example of an acceleration air height of 75 mm.

[0227] Figure 28 shows a graph of the standard deviation of the residence time versus the separator protrusion rate for examples of four acceleration air heights and an example without a separator. The standard deviation of the residence time in the 50 mm example increased as the protrusion rate increased from 0% to 40%. The standard deviation of the residence time was lower at a protrusion rate of 60% for the examples of acceleration air heights of 75 mm, 100 mm, and 200 mm. The standard deviation of the residence time at a protrusion rate of 60% was highest for an acceleration air height of 75 mm. The second highest standard deviation at a protrusion rate of 60% was seen in the 100 mm example, and the 200 mm example had the lowest standard deviation of the residence time. At a protrusion rate of 100%, the highest standard deviation was seen for an acceleration air height of 75 mm, but this was still lower than the standard deviation of the 50 mm example at a protrusion rate of 40%. The standard deviation of the 100 mm example also increased as the protrusion rate increased from 60% to 100%.

[0228] The trend of the horizontal flight distance versus the separator protrusion rate for the four acceleration air heights can be seen in Figure 26. The maximum horizontal flight distance of the acceleration air at a protrusion rate of 0% was a value of 2.5 m for the example of an acceleration air height of 50 mm and was the highest. In the example without a separator, there was only one air flow that moved the minimum horizontal distance within the processing device. The second highest horizontal distance at a protrusion rate of 0% was measured in the 75 mm example, and the third highest horizontal flight distance was in the 200 mm example. From the graph in Figure 26, it can be seen that as the protrusion rate increased from 20% to 60% and further to 100%, the horizontal flight distance of the acceleration air at 100 mm increased. The shortest horizontal flight distance was seen for an acceleration height of 200 mm. This was because the acceleration air diffused over a greater height, reducing the speed of the acceleration air that guides the air vertically. The maximum horizontal flight distance was seen in the 75 mm example at a protrusion rate of 100% because the acceleration air was guided more horizontally along the separator and the speed of the air was maintained as the air spread over a smaller height.

[0229] The graph of FIG. 27 shows the effective height of the curtain for four accelerating air heights for different separator protrusion rates. The effective height of the curtain or "effective height coefficient" defines the straightness of the gas flow within the processing device. The effective height coefficient is defined as a measure of how much of the main air flow is within the processing region of the processing device. When the main air flows through the processing region, there is a downward force on the main air stream. The effective height coefficient at a protrusion rate of 0% was lowest at a value of 0.55 for the example without a separator, second highest at a value of 0.778 for the example with an accelerating air height of 200 mm, and highest at a value of 0.89 for the example with an accelerating air height of 50 mm. For the example with 50 mm, the effective height coefficient was lower at a value of 0.867 when the protrusion rate increased from 0% to 40%. For the example with an accelerating air height of 100 mm, the effective height coefficient was lowest at a value of 0.667 for a protrusion rate of 20%. The effective height coefficient was 0.833 at a protrusion rate of 60% and 0.889 at a protrusion rate of 100%. As the protrusion rate increased, the effective height coefficient increased and the straightness of the gas flow was obtained. This demonstrates the importance of the separator in enabling most of the main air stream to be utilized in the processing region.

[0230] The curtain with a higher percentage of separator protrusions moved the farthest and had the greatest spread of the curtain at the bottom of the duct. This was expected as the separator protrusions enable better momentum transfer and more horizontal contact in the acceleration region. This is in contrast to the example of the simulation without a separator as shown in FIG. 12, which did not induce the gas flow vertically and did not effectively move the curtain horizontally. This is an important consideration for utilizing the duct length and can affect, in particular for higher ducts, how many curtains can be accommodated in a given duct.

[0231] The example of an accelerating air height of 50 mm moved the curtain the farthest (see Table 6 below), because the lower height and higher speed act as a "transition point" for turbulence. As a result, as shown in Figure 13, the curtain became triangular and was able to flow more horizontally in the initial stage. On the other hand, in the example of an accelerating air height of 200 mm, as shown in Figure 26, the speed was smaller, it spread over a larger height, resulting in a more upright (vertical) initial angle, so the horizontal flight distance of the accelerating air was minimized.

[0232]

Table 8

[0233] Typically, the accelerating air height should be minimized to maximize the height of the main air stream. However, there is a very high possibility that there is a limit where the turbulence and angle are too large and the curtain is too turbulent. This can be seen in the CFD diagram of the 50 mm accelerating air height in Figure 13, especially for higher separator protrusion ratios.

[0234] A higher percentage of separator protrusions affected the straightness criterion of the flow (the effective height of the curtain) obtained from the CFD report. The higher the separator protrusion ratio, the better the straightness of the flow. It was expected that by flowing the accelerating air as horizontally as possible, the nose dive effect of the air would be mitigated, and the accelerating air would be induced to descend vertically upstream of the curtain by vortices. This can be seen in the CFD diagrams shown in Figures 12 to 23.

[0235] Regarding the example of an accelerating air height of 75 mm, it can be seen from Figure 14 that the shape of the curtain for the processing device with a protrusion ratio of 0% was the same as that seen in Figure 13 of the 50 mm example. At a protrusion ratio of 60% and an accelerating air height of 75 mm, the curtain had a larger trajectory and moved horizontally over a greater distance compared to the example with a protrusion ratio of 0% (see Figure 15). At a protrusion ratio of 100%, it can be seen from Figure 16 that the curtain had a good trajectory, but the turbulence in the lower region of the curtain increased.

[0236] An example of an acceleration air height of 100 mm with a protrusion rate of 0% produced a curtain that moved a short horizontal distance (see Figure 17). At a protrusion rate of 20%, the horizontal distance the curtain moved increased (see Figure 18). Increasing the protrusion rate to 60% for the 100 mm example showed that the accelerating air remained as horizontal as possible using the entire surface area of the curtain. At a protrusion rate of 100%, the accelerating air remained horizontal after interacting with the curtain, but the particles within the curtain began to show turbulence in the lower region of the curtain.

[0237] Examples of an acceleration air height of 200 mm show a shorter horizontal distance of acceleration. At a protrusion rate of 0%, it was seen that the accelerating air was initially directed vertically (see Figure 21). As shown in Figures 23 and 24, the higher the protrusion rate, the better the straightness of the accelerating air flow.

[0238] The proportion of the separator protrusion affects the curtain volume within the duct for two main reasons. First, the separator protrusion increases the trajectory of the curtain, and as a result, the curtain volume and surface area for a given duct height increase. Second, the separator protrusion can push all particles to be more horizontal and increase particle turbulence. This typically reduces the surface area and volume heat transfer coefficient per unit volume for an embodiment having one curtain.

[0239] The criterion of surface area per unit volume is valid in embodiments with multiple curtains. However, when one curtain is required, the surface area per unit volume is not as important as, for example, the heat load, residence time, and standard deviation of the residence time in the gas-particle treatment device. The straightness of the flow also becomes more important for embodiments with multiple curtains.

[0240] Some of the advantages maximized by a single curtain may not be as beneficial as multiple curtains. The procedure for identifying the preferred design, when a single curtain system is a viable option, involves sacrificing the straightness of the downstream flow, so the viability of a single curtain configuration must be considered before investigating the option of multiple curtains. The CFD-based modeling procedure can facilitate the comparison of such options.

[0241] The straightness of the downstream flow can be controlled by a fan or other means of adding a pressure gradient to control the acceleration of the air to follow the next virtual downstream curtain. This feature was not considered in this investigation but would be considered when investigating the option of multiple curtains.

[0242] Experiment 2 The experimental setup for the bidirectional cross-flow simulation is shown in Figure 31.

[0243] Simulation Design 1 included a bidirectional cross-flow with a gap placed between two cross-flow sections and two accelerating air streams.

[0244] Simulation Design 2 included a unidirectional cross-flow without accelerating air.

[0245] Simulation Design 3 included a unidirectional cross-flow with an accelerating air stream and a separator protrusion rate of 0%.

[0246] The results of the simulation work performed using the three designs are shown in Table 7 below.

Table 9

[0247] The residence time, curtain mass, and surface area did not change dramatically from bidirectional to unidirectional crossflow, as expected. However, the surface area was highest in the design using accelerated air. This enables the curtain to accommodate more mass for a given duct height.

[0248] The heat load was highest in the example of bidirectional crossflow. The unidirectional design can be optimized to achieve the same heat load as the bidirectional design, but the advantage of the bidirectional design is that it can achieve a high heat load with a much smaller footprint. This is the advantage of the compactness of a single curtain.

[0249] Figure 32 shows the CFD diagram of Design 1 of the simulation where bidirectional crossflow was used. The curtain formed in the first crossflow section had a uniform shape because the particles contacted the main air stream flowing from left to right. The particles then entered the second crossflow section and were introduced into the second accelerated air stream flowing in the opposite direction from right to left. The shape of the curtain was the same as that in the first crossflow section.

[0250] Figure 33 shows the CFD diagram of Design 2 of the simulation using unidirectional crossflow without accelerated air. As demonstrated in Experiment 1, the particle stream was initially induced vertically. There was only one horizontal gas stream in the crossflow with the particle stream, and the formed curtain moved horizontally over a short distance and had a smaller surface area than Design 1.

[0251] The CFD diagram of Design 3 of the simulation using unidirectional crossflow with an accelerated air stream is shown in Figure 34. The separator did not protrude from the length of the particle feeder or particle inlet. The curtain formed for Design 3 had a greater spread than that shown in Figure 33 for Design 2. The curtain had a larger surface area compared to Design 2 and had the largest footprint among the three designs.

[0252] The experimental work was carried out using CFD modeling software, but the applicant believes that the same or similar results can be obtained when carried out on a larger scale in a pilot plant.

[0253] The modeling work carried out by the applicant shows that the experimental data of the tested soda ash particles can be estimated for other particles.

[0254] Experiment 3 The results summarized in Table 10 below outline the average slip velocity, dimensionless dispersion of particles, and average residence time on Persian clover seeds when the curtain reaches a steady state. The slip velocity was calculated from the particle Reynolds number extracted from the CFD.

[0255] [Table 10]

[0256] By using a separator with two individual flow rates, it was observed that both the dimensionless dispersion of particles and the average slip velocity were improved. Furthermore, when there was a pressure driving device in the downstream part of the accelerating gas line, the maximum average residence time, the best dimensionless dispersion of particles, and the highest average slip velocity occurred (this is only possible with the upstream and downstream separators).

[0257] A possible reason for the increase in the average slip velocity is that the behavior of the cross-flow gas with respect to the descending particles has become more vertical. This can be shown using the following slip velocity equation, which is the geometric shape and the magnitude of the velocity difference between the particle and the gas. [Equation]

[0258] · x is the horizontal dimension (e.g., length) of the chamber, y is the vertical dimension (e.g., height) of the chamber, and Z is the width dimension of the chamber. · X slipIt is maximized when the gas streamline is perpendicular to the particle flow, i.e., when the x-term of the particle is as close to 0 as possible while the x-velocity of the gas is improved. ·Y slip It is maximized when the gas streamline has a vertical downward velocity as close to 0 as possible while the particles are under gravity. ·Assume that the Z-term can be ignored.

[0259] In the absence of a separator, the particle induces the flow of the gas along with the gas streamline, so the gas streamline becomes more parallel to the particle (decreasing the Y slip term). A separator with a pressure driving device helps to keep the bulk gas flow as vertical as possible, resulting in a higher average slip velocity.

[0260] The graph in Figure 36 is for the particles cited in the investigation of isothermally contacting air at 15 °C, showing the relationship between the slip velocity of the Pershaclover seeds and the heat transfer coefficient and mass transfer coefficient. Figure 36 shows that the slip velocity greatly affects heat transfer and mass transfer, and by optimizing the slip velocity on the particles in the curtain, the contact performance in cross-flow is improved.

[0261] Figure 37 shows the effect of the separator on the slip velocity, with a sharp increase in the slip velocity up to about 9 m / s at a vertical coordinate of about 2.75 m.

[0262] Figures 38 to 40 are CFD diagrams showing the effects of the separator and the pressure driving device on the particle flow profile.

[0263] In summary, the following views were obtained.

[0264] ·The dispersion of particles based on the dimensionless dispersion of particles for the experiments with a separator and the experiments with a separator and a pressure driving device brought about an improvement of 15 - 17% compared to the experiments without a separator.

[0265] · The average slip velocity that controls the rates of heat transfer and mass transfer at the particle surface is up to 26% higher. The relationship between the slip velocity and the heat transfer coefficient and the mass transfer coefficient generally follows a power law (for specific particle sizes and gas properties) that is relatively linear in the region where typical slip velocities exist. Thus, a similar increase in the Nusselt number and the Sherwood number results in an approximately linear increase in the heat transfer coefficient and the mass transfer coefficient with respect to the slip velocity.

[0266] · (Assuming that the curtains being compared have the same trajectory) It is more energy - efficient to accelerate only a part of the cross - section of the chamber rather than the entire cross - section of the chamber.

[0267] · By minimizing the chamber volume consumed by the downstream vortices, the use of separators and pressure - driving devices in a multi - stage processing apparatus becomes more compact.

[0268] · The dimensionless dispersion of particles with respect to one curtain can be conserved for the entire process of the advancing curtain and n curtains.

[0269] Experiment 4 Figure 41 is a CFD diagram of an embodiment of multiple curtains of the present invention without a separator and a pressure - driving part.

[0270] Figure 42 shows the slip velocity distribution of curtain 1, and Figure 43 shows the slip velocity profile of curtain 2 without a separator.

[0271] Table 11 presents the average slip velocity of the curtains in a two - stage processing apparatus according to the present invention. The velocities were calculated from the particle Reynolds numbers extracted from the CFD. [Table 11]

[0272] In the case where there is no separator and pressure driving device, it was found that both curtains have a lower sliding speed compared to the case where a separator with a pressure driving device is used. This is consistent with the applicant's finding that the sliding speed is maximized when optionally using a separator together with a pressure driving device.

[0273] For a system having a separator and a pressure driving device, two different designs (i.e., Design 1 and Design 2) were developed. The parameters of both designs are shown in Table 9.

[0274] [Table 12]

[0275] Table 12 shows that for a multi-stage system having a separator and a pressure driving device, the dimensionless dispersion of the particles of the second curtain increases by 6 times, and the dimensionless dispersion of the overall residence time of the particles increases by about 3 times. This means that as the number of particle curtains increases, the residence time deteriorates and control and reproduction become difficult.

[0276] When the separator and the pressure driving device are installed in place, more reproducible residence time control was observed among Curtain 1, Curtain 2, and the whole process.

[0277] Design 1 shows a dimensionless dispersion of the particles in Curtain 1 of 0.000326 and a dimensionless dispersion in the overall system of the particles of 0.0007248, which is a loss of airtightness nearly twice as much.

[0278] However, in Design 2, the dimensionless dispersion of the particles ranges from 0.000471 to 0.0006834, or a loss of airtightness of about 1.45 times. This is an improvement over Design 1. It is confirmed that by combining the accelerating gas flow and the main gas flow with the separator and the pressure driving device, it is possible to control the total dimensionless dispersion of the particles for the system, and in some cases, the dimensionless dispersion of the particles for the first curtain can be passed on to the nth curtain.

[0279] Another advantage of using a plurality of separators and a pressure driving device is the reduction of the space occupied by the plurality of curtains. There are several reasons for this.

[0280] First, the plurality of separators and the pressure driving device mitigate the formation of downstream vortices.

[0281] Second, the particle curtains formed in a gas-particle treatment device having separators and a pressure driving device have longer trajectories, but the particle curtains can be formed closer to each other.

[0282] One problem faced by a gas-particle treatment device without a separator is that if a second continuous curtain is placed too close to the first curtain (in the middle of the vortex), a steep upward flow of gas is induced at the upstream edge of the second curtain, and then a very strong downward flow through the second curtain is induced. This increases the disturbance of the second curtain and disrupts the residence time distribution and the distribution of slip velocity values.

[0283] A second particle feeder can be used to introduce particles into the chamber. The second particle feeder may be in fluid communication with the particle outlet to reintroduce the particle stream into the chamber. When separators and a pressure driving device are used, the second particle feeder can be placed very close to the first particle feeder, shortening the overall length of the chamber.

[0284] Combining the improved slip velocity with the ability to bring the particle feeders closer together increases the volumetric heat transfer coefficient per chamber volume.

[0285] Design 2 had the best numerical values for the overall residence time distribution and the average slip velocity, but the difference in slip velocity between curtain 1 and curtain 2 was greater than that of Design 1. This is presumably because the two curtains of Design 2 had different trajectories and the accelerating gas was not effectively controlled so that it could penetrate the first curtain and continue to the second curtain.

[0286] It was also observed that in Design 1 and Design 2, the influence on the sliding speed distribution of Curtain 1 and Curtain 2 was different.

[0287] Figure 44 is a CFD modeling diagram of a two-curtain system with particles and gas streamlines, and Figure 45 is a graph showing the sliding speed distribution of Curtain 1 according to Design 1.

[0288] Figure 45 shows the sliding speed distribution of Curtain 1, and Figure 46 shows the sliding speed profile of Curtain 2 according to Design 1. An important effect of the separator on the sliding speed distribution of the particle curtain is the sharp increase in the sliding speed at the separator. In Figures 45 and 46, this sharp increase is observed at a vertical coordinate of approximately 2.5 m.

[0289] Figure 47 is a CFD modeling diagram of a two-curtain system with particle streamlines and gas streamlines according to Design 2 of Experiment 4. Figures 48 and 49 are graphs showing the sliding speed distributions of Curtains 1 and 2 according to Design 2 of Experiment 4, respectively.

[0290] Since Design 1 has a lower accelerating gas speed, its sliding speed within the accelerating gas zone is lower, resulting in a "flatter" distribution. However, Design 2 uses a higher accelerating gas speed and thus has a more "parabolic" sliding speed distribution. In this observation, in both cases, it is possible to visually recognize better in Curtain 1, but Curtain 2 has a larger distribution of sliding speed due to the turbulence generated from Curtain 1.

[0291] The simulation and results of Experiment 4 demonstrate the following results.

[0292] 1. The separator and the pressure driving device are beneficial for multi-stage operation because they maximize the sliding speed.

[0293] 2. The separator improves the overall airtightness of the residence time of the entire process (n curtains) (according to the criterion of dimensionless dispersion).

[0294] 3. The dimensionless dispersion of the particle values extracted from the single-stage simulation can be used for the curtain of n.

[0295] It should be understood that where a prior art publication is cited in this specification, such citation does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or any other country.

[0296] In the following claims and the foregoing description of the invention, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

1. A gas-particle treatment apparatus for bringing a particle stream into contact with a gas stream, comprising: a chamber; at least one gas inlet for introducing gas into the chamber, the gas forming an accelerating gas stream and a main gas stream within the chamber; a particle feeder in fluid communication with a particle inlet for introducing the particle stream into the gas; a separator for separating the accelerating gas stream from the main gas stream in at least a portion of the chamber, the accelerating gas stream having a higher average velocity than the main gas stream to form a curtain of the particle stream having an upstream edge and a downstream edge; a particle outlet for receiving the curtain of the particle stream; and a gas-particle treatment apparatus comprising the same.

2. The gas-particle treatment apparatus according to claim 1, wherein the curtain of the particle stream is configured such that the dimensionless dispersion of the residence time of the particles is reduced by at least 5% as compared to the curtain of the particle stream formed in a gas-particle treatment apparatus without a separator.

3. The gas-particle treatment apparatus according to claim 1 or claim 2, configured to achieve an average slip velocity that is at least 10% higher as compared to a gas-particle treatment apparatus without a separator.

4. The gas-particle treatment apparatus according to any one of claims 1 to 3, wherein the at least one gas inlet is configured to introduce gas substantially horizontally into the chamber.

5. The gas-particle treatment apparatus according to any one of claims 1 to 4, wherein the particle inlet is configured to introduce a substantially vertical particle stream into the gas stream.

6. The gas-particle treatment apparatus according to claim 5, wherein the particle inlet is configured to feed the particle stream into the accelerating gas stream.

7. The gas-particle treatment apparatus according to any one of claims 1 to 6, configured such that less than 10% by weight of the particle stream contacts the separator.

8. The gas-particle treatment apparatus according to any one of claims 1 to 7, comprising a solid separator.

9. The gas-particle treatment apparatus according to any one of claims 1 to 7, comprising a perforated separator.

10. The gas-particle treatment device according to any one of claims 1 to 9, comprising at least two pairs of particle inlets and particle outlets, wherein the first particle outlet is in fluid communication with the second particle inlet.

11. The gas-particle treatment device according to claim 10, wherein the separator is disposed upstream or downstream of the particle outlet.

12. The gas-particle treatment device according to any one of claims 1 to 11, comprising a pressure driving device for introducing a positive pressure into the accelerated gas stream.

13. The gas-particle treatment device according to any one of claims 1 to 12, wherein the separator is disposed so as to obtain a gap angle greater than 20°.

14. A method of contacting a particle stream with a gas in a chamber, comprising: (i) introducing the gas into the chamber, wherein at least a portion of the gas forms an accelerated gas stream and a main gas stream in the chamber, and the accelerated gas stream has an average velocity higher than that of the main gas stream; (ii) introducing the particle stream into the gas to form a curtain of the particle stream having an upstream edge and a downstream edge. A method comprising the above.

15. The method according to claim 14, comprising controlling the gas stream into the chamber such that the dimensionless dispersion of the residence time is reduced by at least 5% as compared to the curtain of the particle stream formed in a gas-particle treatment device without a separator.

16. The method according to claim 14 or claim 15, comprising controlling one or more of the gas stream velocity, the particle stream velocity, the position and size of the separator, and the chamber dimensions to achieve an average slip velocity at least 10% higher than that of a gas-particle treatment device without a separator.

17. The method according to any one of claims 14 to 16, comprising controlling one or more of the gas stream velocity, the particle stream velocity, the position and size of the separator, and the chamber dimensions such that less than 10% by weight of the particle stream contacts the separator.

18. The method according to any one of claims 14 to 17, comprising introducing the gas stream substantially horizontally into the chamber.

19. The method according to any one of claims 14 to 18, comprising introducing a substantially vertically oriented particle stream into the gas stream. **Claim 20** The method according to claim 19, comprising introducing the particle stream into the accelerated gas stream. **Claim 21** The method according to any one of claims 14 to 20, comprising introducing a positive pressure into the accelerated gas stream to increase the velocity of the accelerated gas stream.

Images