Patent Application
20090145846
None.
In the treatment of water, it is known in the industry to use conical sludge blanket clarifiers (CSBC) for clarification and cold lime softening applications. CSBCs incorporate a cylindrical inlet flow device located at the bottom of an inverted conical vessel. Liquid enters the cylindrical inlet flow device at multiple tangential inlet ports which creates an upward helical liquid flow pattern. In its typical operation, a CSBC contains a sludge blanket of suspended solids within the inverted conical vessel.
It is also known in the industry to use fluidized bed biological reactors (FBBR) containing sand media to treat wastewater. FBBRs containing sand media having a high specific surface area per unit volume of media (M2/m3) which provides for high biomass concentrations, hence high biological loadings. FBBRs have influent distribution systems which must achieve uniform distribution of influent liquid flow across the entire reactor area, prevent plugging and media escape, minimize abrasive wear, and minimize shearing of biomass above the influent distribution manifold. Typical influent distribution systems include a header manifold, lateral pipes branching from the header manifold, and nozzles attached to the lateral pipes pointing down towards the bottom of the reactor. The liquid flow pattern within FBBRs is primarily vertical from the influent distribution systems to the overflow collectors.
It is also known in the industry to use fluidized bed chemical reactors (FBCR) to remove calcium compounds, such as calcium carbonate, from low magnesium raw waters. FBCRs typically have inverted conical configurations with very steep sidewalls. The fluidized bed media used in FBCRs often consists of fine sand. FBCRs have tangential inlet ports which creates an upward helical liquid flow pattern.
CSBCs do not provide an ion exchange process, which can further purify and decontaminate liquids. With fluidized bed reactors, any suspended solids contained in the inlet liquid and any suspended solids generated within the reactor will be contained in the outlet liquid. Typically, the suspended solids must be removed in a separate process that follows the fluidized bed reactor. In fluidized bed reactors utilizing ion exchange, high concentrations of non-target ions will often be discharged in the outlet liquid as the fluidized bed becomes saturated with the target ions.
Accordingly, a need exists for an apparatus and method that can remove suspended solids as well as effecting a fluidized bed media. A need also exists for a fluidized bed reactor that allows for the reduction of non-target ion concentration spikes. A further need exists for a fluidized bed reactor that has enhanced reaction kinetics, which leads to shorter detention times, smaller vessels, and lower costs.
The present invention is directed to a fluidized bed apparatus that provides removal of various contaminants using fluidized bed media in addition to the removal of suspended solids. In accordance with one embodiment of the invention, a fluidized bed reactor includes a lower section effecting a rotational flow component, a generally conical middle section, an upper section containing fluidized bed media, and optionally a means for removing particular matter. A tangential inlet port preferably feeds, liquid into the lower section to assist in developing an upward helical liquid flow pattern in the middle section. The Fluidized bed media may be used to perform an ion exchange process or a variety of other processes for removing contaminants.
The present invention is also directed to a method of removing soluble and particulate matter from a liquid including the steps of introducing a liquid into a first vessel in a manner creating an upward helical flow of the liquid, discharging the liquid from the first vessel in a generally conical second vessel that overlies the first vessel therefore causing a decrease in the vertical velocity component of the generally helical flow as the liquid moves up through the second vessel, and passing the liquid generally upward through a fluidized bed media that is located above the second vessel and formulated to remove selected contaminants from the liquid.
In the accompanying drawings:
The present invention is directed toward a fluidized bed reactor 10 and method for removing soluble and particulate matter from a liquid. As shown in
The lower section 12 includes a wall 18, an upper end 20, and a lower end 22. In one embodiment, the lower section wall 18 is generally cylindrical. However, it will be appreciated by those skilled in the art that the lower section wall 18 can alternatively be constructed in other geometries, including a generally conical configuration. Tangential inlet ports 24, 26 allow untreated liquid to be fed into the lower section 12. As illustrated in
The inlet ports 24, 26 are positioned tangential to the inner surface of the lower section wall 18. A tangential positioning of the inlet ports 24, 26 in the lower section 12, along with the removal of liquid from the upper section 16, serves to develop an upward helical flow of the liquid in the lower section 12 and the middle section 14. The helical flow may also continue into the upper section 16. The helical flow results in the liquid traveling in an elongated flow path.
Flow directing vanes 28 may be provided to be in communication with the inlet ports 24, 26. The flow directing vanes 28 can be adjusted to vary the inlet velocity of liquid into the lower section 12. As illustrated in
The middle section 14 includes a wall 34, an upper end 36, and a lower end 38. In one embodiment, the middle section wall 34 is generally conical and extends upwardly and outwardly from the lower section upper end 20 to the upper section lower end 46. The primary function of the middle section 14 is to reduce the vertical velocity vector of the upward helical liquid flow. As the liquid rises in its upward helical path through the generally conical middle section 14, it spreads to fill the increasing cross-sectional area of the middle section 14. This results in a corresponding decrease in the vertical velocity vector of the liquid traveling through the middle section 14, while the net flow rate of the liquid through the middle section 14, as well as the net flow rate of the liquid through the entire reactor 10, remains constant.
The vertical velocity of the liquid continues to decrease until it reaches a portion of the reactor 10 having a constant cross-sectional area. Proximate the upper section lower end 46, the vertical velocity of the liquid is generally equal to the velocity required to keep the fluidized bed media 48 in section 16 suspended. In other words, the lifting force of the liquid and the counteracting gravitational force on the fluidized bed media 48 are in equilibrium. The vertical velocity that is required to keep the fluidized bed media 48 suspended is a function of multiple factors, including the density, shape, and size of the fluidized bed media 48, as well as the temperature, density, and viscosity of the liquid being treated.
In one embodiment, the middle section wall 34 is inclined at an angle of 40 to 60 degrees from the horizontal to provide for the proper rate of decrease in the vertical velocity of the liquid and to prevent the fluidized bed media from settling and accumulating on the wall 34. Depending upon the vertical velocity of the liquid, there can be fluidized bed media 48 contained in the middle section 14, as well as the upper section 16. As shown in
The upper section 16 includes a wall 42, an upper end 44, and a lower end 46. In one embodiment, the upper section wall 42 is generally cylindrical. However, it will be appreciated by those skilled in the art that the upper section wall 42 can alternatively be constructed in other geometries, including square, rectangular, or generally conical configurations. When the upper section wall 42 is generally conical, or configured in any other geometry having an increasing cross-sectional area, the vertical velocity of the liquid traveling through the upper section 16 will continue to decrease until it reaches a point where the cross-sectional area of the of the upper section 16 is no longer increasing and becomes constant.
As illustrated in
It is desirable to have the ability to replace, regenerate, and/or rejuvenate the fluidized bed media 48 while the reactor 10 is in use. In order to replace, regenerate, and/or rejuvenate the fluidized bed media 48, the reactor must include a means for removing fluidized bed media and a means for adding fluidized bed media. As shown in
One of the events triggering removal of fluidized bed media 48 from the reactor 10 occurs when the fluidized bed media 48 reaches a level above its maximum desirable upper level. Again, the overflow dam 76 is located at a height equal to the maximum desirable upper level of the fluidized bed media 48. Once the fluidized bed media 48 reaches a level above the overflow dam 76, the fluidized bed media 48 can enter the region directly above the hopper 70. In this region directly above the hopper 70, the vertical velocity of the liquid is decreased due to the hopper 70 deflecting the upward flow of the liquid. This decrease in vertical velocity results in the liquid having a vertical velocity less than that required to keep the fluidized bed media 48 suspended. In other words, in the region directly above the hopper 70, the lifting force of the liquid is less than the counteracting gravitational force on the fluidized bed media 48. Therefore, the fluidized bed media 48 descends into the hopper 70. Once the fluidized bed media 48 is in the hopper 70, it can be removed through the hopper's outlet port 78.
As illustrated in
The upper section 16 can also include a means 50 for removing particulate matter, such as suspended solids, from the liquid. As shown in
As shown in
The buoyant granular media 54 may require occasional backwashing. The backwashing is accomplished by diverting outlet flow from the primary outlet 64 to a secondary outlet 65 and adding air uniformly through an air distribution grid 58 located beneath the granular media filter 54.
As shown in
The reactor 10 can also include a flow collection system 62 (
Several treatment processes can be achieved within the fluidized bed reactor 10 of the present invention, including biological processes, ion exchange processes, physical adsorption processes, and chemical precipitation processes. The biological processes can include the anoxic de-nitrification of waters containing nitrates. The ion exchange processes can include the ion exchange of soluble ions, molecules, or compounds on synthetic or natural ion exchange media. For example, one ion exchange process involves the removal of disinfection by-product precursors from waters. The physical adsorption processes can include the physical adsorption of soluble ions, molecules, or compounds on the surface of adsorbents. For example, one physical adsorption process involves the removal of soluble organic contaminates upon activated carbons. The chemical precipitation processes can include the chemical precipitation upon inert media. For example, one chemical precipitation process involves cold lime softening for the removal of calcium such as calcium carbonate.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.
The constructions described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.
