RU2403966C2 - Reactor with pseudoliquid layer - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention can be used for purification of gas mixes, including furnace waste gases or incineration plant waste gases, fuel or wastes combustion, chemical reactions in pseudoliquid layer. Reactor housing fluidising chamber accommodates taper-shaped insert. Space with circular cross section is formed between housing inner wall and insert outer surface to make said fluidising chamber wherein gas flow rate either is constant or increases depending upon mutual arrangement of the housing and the insert.

EFFECT: reactor stable operation in wide range of loads, improved conditions of solid phase agglomerates removal.

10 cl, 5 dwg

Description

The invention relates to a fluidized bed reactor equipped with a fluidizing chamber, an inlet gas port and an outlet gas port. If necessary, the inlet and outlet gas ports can be made in the form of many gas ducts.

The background of the invention

During operation of such a reactor, a so-called fluidized bed is formed in its fluidizing chamber. It consists of a gas in the medium of which solid-phase particles are distributed, and this gas is in a turbulent state. As a result of this turbulence in the fluidized bed, good mixing of the solid and gas phases, as well as the water supplied to the fluidized bed is ensured, which ensures the possibility of optimal mass transfer or adsorption. In various kinds of chemical processes, classic fluidized bed reactors, fluidized bed circulation reactors, or the so-called fluidized bed reflux reactors are used. In most cases, gas passes through the reactor from the bottom up. After the gas inlet port, the reactor has a cramped region, which contains either a fluidizing plate (perforated), one nozzle, or a set of nozzles (hereinafter, the term "nozzle bottom" will be used). In this cramped area, the gas velocity should be high enough to prevent solid-state particles from settling on the bottom. Above the cramped area is a fluidizing chamber, which may be cylindrical or conical in shape, or a combination of a conical part and the following cylindrical part. Above the fluidizing chamber in most reactors, there is an outlet duct oriented laterally and incised into the side wall of the reactor. In other reactors, the outlet flue is made in the center and goes up. Known fluidized bed reactors have a significant drawback that due to the changing intensity of the gas stream (which may be caused, for example, by the operation of systems located on the production line behind the reactor), fluctuations in the fluidized bed occur, which reduces the efficiency of the process and / or is the cause of prolonged malfunctions, for example, the operation of a system located on the production line behind the reactor. As a countermeasure, gas recirculation or air supply is used in addition to the inlet gas stream, so that the minimum power of the gas stream passing through the reactor does not fall below 60% of the total stream power for most cases. Systems connected to the reactor often require fluctuations in the gas flow power in the range from 30% to 100% of full power for their operation, and stabilization of the process in the reactor (i.e., to increase the gas flow power to more than 60% of full power) requires significant energy costs and additional equipment.

A brief description of the invention

One of the objectives of the invention is the creation of such a fluidized bed reactor, the fluidized bed of which would proceed with almost constant parameters (in particular, with a constant gas flow rate), and could be optimally controlled even with varying values of the input gas stream power (for example, ranging from 30% to 100% of maximum power).

To achieve this, the fluidization chamber (2) included in the reactor (1) has a housing (3) made in the shape of a cone or paraboloid, in which an insert (4) is also made in the shape of a cone or paraboloid. With this design, between the inner surface of the housing (3) and the outer surface of the insert (4), a ring-shaped space is formed which serves as a fluidizing chamber (2), and in which it is possible to control the gas flow rate, which can be maintained at a constant level, to increase or decrease depending on the relative position of said body (3) and insert (4). With this technical solution, it is possible to maintain the gas flow rate at a constant level under loads varying over a wide range, therefore, such a reactor can also be called a reactor with a constant gas flow rate.

When the insert (4) is moved up or down along the central longitudinal axis of the fluidizing chamber (2) (the direction is indicated by the double arrow (5)), the gas flow rate in the fluidizing chamber increases or decreases. Thus, when the velocity of the gas stream supplied to the reactor is changed by raising and lowering the insert (4), it is possible to maintain the gas stream velocity in the space of the fluidizing chamber with an annular cross-section at a constant level.

The design of the reactor may be such that the annular cross-section of the fluidizing chamber (2) can be increased or decreased (see Fig. 1 or 2).

The present invention makes the use of the above expensive countermeasures unnecessary. Moreover, when applying the present invention, conditions are provided for stable operation of the reactor over a wide range of loads, which in the case of known reactors takes place only at constant gas flow rates. When using a reactor with a constant fluidizing chamber with an annular cross-section, the adverse effect of fluctuations in the gas flow on the operation of systems located on the production line in front of and behind the reactor is minimized. When using a reactor with a fluidized bed, the space of the fluidizing chamber of which has an annular cross-section and the geometry of the body and tabs of which corresponds to the technical solution of the present invention, it is possible to optimize the processes occurring in the fluidized bed, in particular, when changing the power of the gas stream through the fluidized bed of the reactor it is possible to avoid the adverse effects of these fluctuations in the gas flow on the operation of systems located on ogicheskoy line in front and behind the reactor.

Another disadvantage of the known fluidized bed reactors is that inside circulating fluidized beds, as well as inside static fluidized beds that do not work with constant gas flow powers, solid state phase agglomerates may fall (settle), mainly along the walls. When these solid state phase agglomerates fall into a confined region, they decompose under the action of a high-speed gas stream, which can lead to significant pressure peaks, in particular, at loads less than 70-80% of the maximum, such pressure peaks can lead to significant disturbances operation of the installation, which, in turn, impedes the normal operation of the installation.

In overcoming this disadvantage is the second objective of the invention.

To solve this problem, the present invention provides for the introduction of a solid state phase separator (6) for separating agglomerates in the reactor structure (see FIG. 4), which is implemented as an opening having an annular cross-section or in the form of a large number of holes located around the periphery of the fluidizing chamber (2) a reactor (1) with a fluidized bed, or in the form of a hole located in the center of the reactor. The holes can be located either in the expanding conical part of the fluidizing chamber (2) below its cylindrical part directly at the junction of the conical and cylindrical parts of the fluidizing chamber (2), or in the cylindrical part of the known fluidized bed reactor, or at any point of the nozzle bottom , or at any point on the outer wall or inner conical surface having an annular cross-section of the space of the fluidized bed.

The separator (6) described here for separating agglomerates of the solid phase, the use of which optimizes the operation of the fluidized bed reactors, is designed in such a way that it is possible to remove agglomerates from the fluidizing chamber (2) through openings located around the periphery of the fluidizing chamber (2), or through an outlet located in the nozzle bottom. In particular, when carrying out processes in a fluidized bed at variable loads (variable power of the gas flow), when applying the present invention, conditions are provided for more stable operation, as well as a significant reduction in the effect on other systems of the production process.

The purpose of the said separator (6) for separating agglomerates of the solid phase is to remove agglomerates and conglomerates of the solid phase from the circulation circuit in the fluidizing chamber (2). Subsequently, these agglomerates and conglomerates of the solid state phase can be returned to the fluidized bed through controlled or unregulated feeders (7). Figure 4 shows such a separator (6) for separating solid-state agglomerates with an opening having an annular cross-section. With this technical solution, these solid state agglomerates are fed to the flotation tray (8), from which they can be re-fed into the fluidized bed reactor in a controlled manner, for example, along several lines evenly distributed around the periphery.

When using such a separator for separating agglomerates of the solid-state phase, costs are reduced that were unavoidable in the prior art. Moreover, in the presence of such a separator for separating agglomerates of the solid-state phase, conditions are provided for more stable operation of the reactor (1) in a wide range of loads, which in the prior art was possible only at relatively low loads (at low gas flow rates). When using such a separator (6) for separating agglomerates of the solid-state phase, the adverse effects of fluctuations in the gas flow on the operation of systems located on the production line in front of and behind the reactor are also minimized (1).

Another problem that occurs when using known fluidized bed reactors is associated with the outlet duct. In known fluidized bed reactors with a design pressure, gas with solid-phase particles dispersed in its medium is discharged in one direction through the upper part of the reactor in its center or through the side of the reactor. Typically, in the central part of the gas stream, the power of the stream is higher than in its other parts, as a result of which turbulence occurs in the reactor, in which solid-phase particles circulate near the walls of the reactor. With a central gas outlet, the turbulence is evenly distributed through the top of the reactor, but concentration of solid-phase particles can occur, which can then form agglomerates and fall down along the walls of the reactor. With lateral gas venting, such a concentration of solid-phase particles can be partially avoided, since the formation of vortices with this design is not so pronounced, however, the gas flow remains inhomogeneous, and local solid state phase agglomerates are formed.

The elimination of this phenomenon is another objective of the invention.

The invention provides that gas with solid-phase particles scattered in its medium is first radially discharged and then directed downward, that is, through openings located around the circumference (preferably evenly distributed around the periphery of the reactor) or through an annular section divided into openings (9). (see figure 3). With this technical solution, the removal of solid-phase particles that reach the top of the reactor (1) in the central region of the gas stream, along the shortest route with uniform distribution in radial directions, is ensured. Due to this, it is possible to reduce the size of the agglomerates of the solid-state phase, and also significantly suppress the process of their formation. In particular, when carrying out processes in a fluidized bed at variable loads (variable power of the gas stream) in the case of applying the present invention, conditions are provided for more stable operation of the reactor (1) with a fluidized bed, as well as a significant reduction in the adverse effect of fluctuations of the gas stream on the operation of systems, located on the technological line in front of and behind the reactor (1).

A further detailed description of the invention will be based on examples of its preferred implementation with reference to the accompanying drawings.

Brief description of the attached drawings

Figure 1 schematically shows one of the embodiments of the invention - the reactor (1) with a fluidized bed having an annular cross-section.

Figure 2 schematically shows another embodiment of the invention - the reactor (1) with a fluidized bed having an annular cross-section.

Figure 3 schematically in a perspective view shows the structure of the outlet gas port in the reactor (1) with a fluidized bed according to the invention.

Figure 4 schematically in a perspective view shows the structure of a separator (6) for separating solid phase agglomerates in a fluidized bed reactor (1) according to the invention.

Figure 5 shows a simplified block diagram of a fluidized bed reactor (1) according to the invention, behind which a solid phase separator (6) and a solid phase recirculation channel are located on the production line.

Detailed Description of the Invention

As can be seen in FIG. 1 or FIG. 2, the fluidization chamber (2) of the reactor (1) contains a cone or paraboloid-shaped body (3), inside of which there is an insert (4), which also has the form of a cone or paraboloid, respectively. With such a constructive solution, between the inner surface of the housing (3) and the outer surface of the insert (4) (work surfaces), a space is formed having an annular cross-section, the parameters of which determine the gas flow rate (depending on the relative position of the work surfaces, this speed can be maintained at a constant level - increase or decrease), and which serves as a fluidizing chamber (2). Therefore, such a fluidized bed reactor (1) can be called a reactor providing a constant gas flow rate.

When the insert (4) is moved up or down by means of a regulating device (not shown), as shown by the double arrow (5), the geometry of the fluidized chamber (2) having a ring-shaped cross section changes, resulting in an increase or decrease in velocity in this space gas flow. Thanks to this technical solution, when the flow rate of the gas supplied to the reactor is changed, it can be ensured that the gas flow rate in the annular cross-sectional space of the fluidizing chamber (2) is kept almost constant, for which it is sufficient to lower or raise the insert (4). The annular fluidized chamber (2) having an annular cross-section can be configured to expand or contract from bottom to top (see FIG. 1 and FIG. 2, respectively). The fluidized bed reactor (1) according to the invention is equipped with a separator (6) for separating solid phase agglomerates (see FIG. 4), which is implemented as an opening having an annular cross-section, or it can be implemented as a large number of holes, located on the periphery of the fluidization chamber (2) of the reactor (1) with a fluidized bed, or in the form of a hole located in the center of the reactor (1). The opening, openings or opening of the separator (6) for separating agglomerates of the solid phase can be located either in the expanding conical part of the fluidizing chamber (2) below its cylindrical part directly at the junction of the conical and cylindrical parts of the fluidizing chamber (2), or in the cylindrical part fluidized bed reactor (1), or at any point on the nozzle bottom, or at any point on the outer wall or inner conical surface having an annular cross-section of the space ps fluidized bed. When using a separator (6) for separating agglomerates of the solid phase, these agglomerates are deflected, mainly in the lateral directions, until they reach the nozzle bottom of the annular flotation tray (8). Agglomerates that remained non-deflected and reached the holes of the nozzle bottom are removed from it using a special device, which is not shown in the accompanying drawings.

The purpose of the separator (6) for separating agglomerates of the solid-state phase is to remove circulating agglomerates and conglomerates from the fluidizing chamber (2). This solid phase can then be fed back into the fluidized bed through controlled or unregulated feeders (7).

Figure 4 shows such a separator (6) for separating agglomerates of the solid phase with an opening having an annular cross-section. With this technical solution, these solid-state agglomerates are fed to the flotation tray (8), from which they can be re-fed into the reactor (1) with a fluidized bed in a controlled manner, for example, along several lines forming unregulated feeders (7) uniformly distributed around the periphery.

With this technical solution, the creation of conditions for more stable operation in a wide range of loads is ensured, which at the prior art was possible only at relatively low loads (at low gas flow rates). When using such a separator (6) for separating agglomerates of the solid-state phase, the adverse effects of fluctuations in the gas flow on the operation of systems located on the production line in front of and behind the reactor are also minimized (1).

Figure 3 schematically shows a reactor (1), the gas outlet port of which is made in the form of ring-shaped openings (9), which in preferred embodiments of the invention are distributed uniformly around the periphery of the reactor (1), while allowing gas to pass through them solid-phase particles scattered in its medium, first in radial directions, and then, if necessary, down, in the direction shown by the arrow (10). With this technical solution, the removal of solid-phase particles that have reached the top of the reactor (1) in the central region of the gas stream is ensured along the shortest route with their uniform distribution in radial directions. Due to this, it is possible to significantly suppress the formation of agglomerates of the solid phase, as well as reduce their size. In particular, when carrying out processes in a fluidized bed at variable loads (variable power of the gas stream) when applying the present invention, conditions are provided for more stable operation of the reactor with a fluidized bed, as well as a significant reduction in the adverse effects of fluctuations of the gas stream on the operation of systems located on the production line in front of and behind the reactor (1).

The outlet gas port having a ring-shaped cross section can be equipped with a guide cone (11) (see FIG. 2), due to which a further improvement in the conditions of gas outlet is achieved, in the medium of which solid-phase particles are dispersed.

The inlet gas port of the fluidized bed reactor of the invention has one or more nozzles (for example, an annular section), or it may have a fluidized bed.

As can be seen in FIG. 5, the fluidized bed reactor (1) according to the invention, connected to a solid phase separator (12), which is located on the production line behind the reactor (1) and connected to the container or flotation tray (13) through descent, or made as one unit (14), this separator (12) of the solid phase is designed to collect the solid phase. The container or flotation tray (13) is also connected to the reactor (1) through a channel (15), configured to return the solid phase through it back to the reactor (1) or remove it.

The fluidized bed reactor (1) according to the invention is characterized in that the solid phase separator (12) located on the production line behind it is configured to control differential pressure (i.e., the difference between the pressure inside the separator (12) and the pressure outside it) in such a way that this differential pressure is lower at lower gas flow rates and higher at higher gas flow rates.

The fluidized bed reactor of the invention may find application in the following branches of technology:

(a) purification of exhaust gases from furnaces or waste incinerators;

(b) purification of gas mixtures of any kind;

(c) the combustion of fuel or waste in a fluidized bed;

(d) technological processes using catalysts, adsorption, and / or absorption;

(e) chemical reactions carried out in a fluidized bed with the aim of chemical transformations of substances in the fluidized bed.

Claims (10)

1. The reactor (1) with a fluidized bed, characterized in that its fluidizing chamber (2) is equipped with inserts that provide the ability to change the cross section of the said fluidizing chamber (2) in such a way that it is possible to control the speed of the gas flow both when changing and at a constant power of the gas stream. 2. The fluidized bed reactor according to claim 1, characterized in that its fluidizing chamber (2) contains a housing made in the form of a cone or paraboloid with a vertical longitudinal axis, in which the insert (4) is also made in the form of a cone or paraboloid with a vertical longitudinal axis, while between the inner surface of the said housing and the outer surface of the said insert (4) a space is formed having an annular cross-section and serving as a fluidizing chamber, while adjusting devices for changing the relative position of said body (3) and insert (4) by moving the insert (4) up or down along the vertical longitudinal axis in order to change the cross-sectional parameters of said space having an annular cross-section. 3. The fluidized bed reactor (1), characterized in that its gas outlet port is made in the form of an aperture with an annular cross-section, or in the form of holes (9) distributed around the periphery of the fluidizing chamber, while the gas is released from the reactor ( 1) with uniform distribution in radial directions. 4. The fluidized bed reactor (1), characterized in that its fluidizing chamber is provided with an aperture (6) having an annular cross-section, or openings evenly distributed around its periphery, or one or more openings of any shape, as a result of which it is possible to remove from the fluidizing chamber of circulating solid-phase particles, solid phase agglomerates and other solid phase separately from the gas stream. 5. The fluidized bed reactor (1) according to claim 4, characterized in that said hole (s) for removing the solid state phase are located inside or on top of the nozzle / nozzles of the inlet gas port, or on the bottom of the fluidization chamber, consisting of several nozzles or representing a fluidizing bed. 6. The fluidized bed reactor (1) according to any one of claims 1 to 4, characterized in that the inlet gas port of its fluidizing chamber has one or more nozzles, for example, a nozzle / nozzles with an annular cross-section or a fluidizing bottom. 7. The fluidized bed reactor (1) according to any one of claims 1 to 4, characterized in that it is connected to a solid phase separator (12) located on the production line behind it, which is connected to the container or flotation tray (13) by means of a pipe , or is made as one unit (14), wherein said solid phase separator (12) is designed to collect the solid phase, and the container or flotation tray (13) is also connected to the reactor (1) via a channel (15) configured to returning through it the solid phase back to the reactor (1) sludge remove it. 8. The fluidized bed reactor (1) according to claim 7, characterized in that said solid phase separator (12) located on the production line behind the reactor (1) is configured to control the differential pressure therein so that it is differential pressure is lower at lower gas flow rates and higher at higher gas flow rates. 9. The fluidized bed reactor (1) according to any one of claims 1 to 4, characterized in that its gas outlet port is provided with a guide cone (11). 10. The reactor (1) with a fluidized bed according to any one of claims 1 to 4, characterized in that it is used for any of the following applications:
(a) purification of exhaust gases from furnaces or waste incinerators,
(b) purification of gas mixtures of any kind,
(c) the combustion of fuel or waste in a fluidized bed,
(d) processes using catalysts, adsorption, and / or absorption,
(e) chemical reactions carried out in a fluidized bed with the aim of chemical transformations of substances in the fluidized bed.

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