Seawater aeration system

Abstract

The invention relates to an aeration system for seawater oxidation in flue gas purification devices, with at least one tubular diffuser (TD), covered by at least two perforated membranes (20), which are positioned one after the other and at a distance to each other in a direction of the central longitudinal axis (A) of the diffuser (TD) as well as at least one support member (SP), which encircles a membrane-free section (FS) of the tubular diffuser at least partially, and at least one sliding means (40), arranged between the support member (SP) and the membrane-free section (FS) of the tubular diffuser (TD).

Claims

1. An aeration system for seawater oxidation in flue gas purification devices, comprising a) a tubular diffuser (TD), comprising a tubular body (10), defining an inner hollow space (10H) and a central longitudinal axis (A), wherein the tubular body (10) has zones featuring air outlet ports (10P), each of which extends from the hollow space (10H) outwardly and through the tubular body (10), b) at least two tubular, perforated, elastic membranes (20), which are positioned one after the other in a direction of the central longitudinal axis (A) as well as over and in contact with said zones of the tubular body (10) featuring outlet ports (10P), and with their corresponding end-zones at a distance (d) to each other, thereby defining at least one membrane-free section (FS) of the tubular body (10), c) at least one support member (SP), which encircles the membrane-free section (FS) of the tubular body (10) at least partially, and d) at least one sliding means (40), arranged between the support member (SP) and the membrane-free section (FS) of the tubular body (10), to allow a movement of the tubular body (10) within the support member (SP) in the direction of the central longitudinal axis (A).

2. The aerations system according to claim 1, wherein the support member (SP) comprises a leg (60), which in its mounted position extends substantially vertical from a first end, at a bottom (B) of a corresponding vessel, containing the seawater, upwardly to a second end, followed by a bracket (50) which encircles the membrane-free section (FS) at least partially.

3. The aeration system according to claim 1, wherein the support member (SP) comprises a leg (60), which in its mounted position extends substantially vertical from a first end, at a bottom (B) of a corresponding vessel, containing the seawater, upwardly to a second end, followed by a bracket (50) which encircles the membrane-free section (FS) and adjacent end zones of two membranes at least partially.

4. The aeration system according to claim 1, wherein the sliding means (40) is ring shaped.

5. The aeration system according to claim 1, wherein the sliding means (40) is a discrete sliding ring.

6. The aeration system according to claim 1, wherein the sliding means (40) is a discrete sliding split ring.

7. The aeration system according to claim 1, wherein the sliding means (40) is fastened to the support member (SP).

8. The aeration system according to claim 1, wherein the sliding means (40) has a surface roughness, which is smaller than that of the tubular body (10).

9. The aeration system according to claim 1, wherein the sliding means (40) is made of polytetrafluorethylene (PTFE).

10. The aeration system according to claim 1, wherein the sliding means (40) has a concave profile at its surface (40S) facing the tubular body (10).

11. The aerations system according to claim 1, wherein the support member (SP) comprises a bracket (50), which is ring-shaped and made of two half shells (52, 54) with one hinge (56) in between and means for locking the bracket (50) when the two half shells (52, 54) commonly form a closed ring.

12. The aerations system according to claim 1, wherein each membrane (20) is fastened at both its end sections to the tubular body (10) by fixings means (30).

13. The aerations system according to claim 12, wherein the fixing means (30) are arranged at a distance to the respective free ends of the membrane (20), thereby defining two terminal sectors of the membrane (20) between the corresponding fixing means (30) and free ends, wherein both terminal sectors of each membrane (20) are folded oppositely to each other in a manner to overlap the fixing means (30) of the corresponding end zone and to provide two end sections, lying onto adjacent parts of the membrane (20).

Description

(1) The invention will be further described with respect to the attached schematic drawing, wherein

(2) FIG. 1: is a side view onto a tubular diffuser arranged at the bottom of an aeration basin of a flue gas purification unit,

(3) FIG. 2: is an enlarged view onto section II as displayed in FIG. 1, partly cut away,

(4) FIG. 3: is an enlarged view onto section III as displayed in FIG. 1, partly cut away,

(5) FIG. 4: is an enlarged perspective view onto section II as displayed in FIG. 1, when the bracket is in its open state.

(6) FIGS. 1-4 represent a tubular diffuser TD which comprises the following features:

(7) one tubular body 10 of a total length L of 10 meters, defining an inner hollow space 10H and a central longitudinal axis A, wherein the hollow space 10H extends continuously between a first open end 10F of the tubular body 10 and a second closed end 10G, wherein the open end 10F is connected to a so-called header pipe HP to allow a gaseous medium like air to flow through the header pipe HP into the tubular body 10. A multiplicity of tubular diffusers TD is connected to one header pipe HP; therefore the header pipe HP has a larger inner diameter compared with each of the associated tubular bodies 10.

(8) Each tubular body 10 features a plurality of ports 10P, each of which extends from the inner hollow space 10H outwardly and through the wall of the tubular body 10.

(9) Three tubular, perforated and elastic membranes 20, each of a length of approximately 3 meters, are positioned over and in contact with the tubular body 10 and in spaced relationship to each other in a direction of the central longitudinal axis A.

(10) FIG. 2 displays this distance d between adjacent membranes 20.

(11) Each membrane 20 has two opposed end zones 20.1, 20.2 with corresponding free ends 22.1, 22.2 and one central zone 24 in between.

(12) Each membrane 20 is fastened at both of its end zones 20.1, 20.2 to the tubular body 10 by fixing means 30, namely hose clamps, which hose clamps 30 are arranged at a distance to the respective free ends 22.1, 22.2 of the membrane 20, thereby defining two terminal sectors 26.1, 26.2 of the membrane 20 between the corresponding fixing means 30 and the free ends 22.1, 22.2.

(13) Both terminal sectors 26.1, 26.2 of each membrane 20 are folded oppositely to each other in a manner to overlap the hose clamp 30 of the corresponding end zone 20.1, 20.2 and to provide two end sections 28.1, 28.2 lying onto a further part of the membrane 20.

(14) In other words: Each membrane 20 is fastened to the tubular body 10 at a distance to its free ends 22.1, 22.2 to allow correspondingly defined terminal sectors 26.1, 26.2 to be folded and to overlap the clamps 30 and thus to protect the clamps 30 against the environment and thus against corrosion.

(15) In this embodiment the end zones 20.1, 20.2 of the membrane 30 are not perforated to avoid any ingress of liquid into the space defined by the overlapping terminal sectors 26.1, 26.2 and thus to avoid any contact of the clamps arranged in said space with the environment.

(16) Thereby corrosion of the fixing means is avoided and the service time of the membrane increased.

(17) According to FIG. 2, the two end sections 28.1, 28.2 are further fastened (pressed against the central zone 24 and the tubular body 10 by corresponding hose clamps 32.

(18) Between opposing terminal sectors 26.1, 26.2 of adjacent membranes 20 (i.e. along a distance d, defining a membrane-free section FS), a PTFE sliding ring 40 is arranged with its inner cylindrical surface 40S touching the outer surface 10S of the tubular body 10, which is membrane-free.

(19) In an alternative the inner surface 40S may be concave (see dotted line in FIG. 2)

(20) The outer surface 40E of said sliding ring 40 touches an inner cylindrical surface 50I of a bracket 50 and is arranged between two ribs 50R, radially protruding from said surface 50I of the bracket 50.

(21) The bracket 50 is ring-shaped and made of two half shells 52, 54 with one hinge 56 (FIG. 4) in between and means 58 (a latch, not displayed in detail) for locking the bracket 50 when the two half shells 52, 54 are in a closed position and commonly form a closed ring (FIGS. 2, 3).

(22) The bracket 50 is part of a support member SP and followed by a leg 60 which is fastened to a bottom B of a treatment vessel, for example an oxidation basin for the after treatment of a seawater based absorbent used in a gas scrubber to purify a flue gas from a power plant.

(23) The provision of the sliding ring 40 around a membrane free section of the tubular body 10 allows a movement of the tubular body 10 in an axial direction (longitudinal direction) A-A of the tubular diffuser TD because of a low friction between the inner ring surface 40S and the outer surface 10S of the tubular body 10, while the sliding ring 40 itself remains at its place (secured by said ribs 50R), as the support SP does.

(24) Insofar the position of tubular diffuser TD remains substantially constant, while axial movements can be compensated by said support SPs.

(25) FIG. 3 displays the free end of a tubular diffuser TD with a cap 10C, closing its free end.

(26) Independently of the specific design of the tubular diffusors and support members as disclosed above the aeration system allows a further optimization with respect to the connection between these diffusor pipes and an associated header pipe.

(27) As disclosed above numerous tubular diffusors TD (of diameter x) are fitted to one header pipe HP of diameter X, with X>>x. While the much bigger header pipe is typically made of a GRP material, the tubular diffusors of the required length will often be made of a cheaper material like polypropylene (PP), thereby causing the problem of laminating one to the other. To enable this lamination (layup) it is proposed to coat the corresponding end sections (connecting end) of the PP diffusor pipes with a PP based textile, allowing to increase the surface (surface roughness) vis--vis the header pipe. This can be done as follows: heating up the surface of the PP diffusor pipe until the surface gets viscous (soft), applying a PP based textile onto the heated surface, for example by winding, and preferably after pre-heating the textile itself, eliminating any (air) bubbles between pipe surface and textile and/or within the textile, for example by applying pressure onto the textile coated surface, cooling down of the coated PP pipe.

(28) The textile may be a net (german: Gewebe), a web (german: Gewebe), a roving/german: Roving), a stich bonded fabric (german: Gewirk) or a knitted fabric (german: Gestrick), either as such or applied onto a basic sheet (film), which sheet is then the side facing the pipe surface. This allows to heat up the sheet and to bond the textile via the sheet to said original diffusor surface.

(29) This pre-treated diffusor pipes may be laminated in a further treatment step to the header pipe, in particular into corresponding holes (openings) of the GRP header pipe. This can be done in a conventional manner, for example by using an epoxy resin or vinyl ester resin as joining element/putty.