COUNTER CURRENT LIQUID GAS EVAPORATION AND CONDENSATION APPARATUS WITH FRAGMENTATION PLATES

Abstract

A method and apparatus for purifying a fluid are disclosed. An evaporation unit and a condensing unit are employed. Each unit has a chamber and a plurality of spaced-apart fragmentation plates, each plate spanning at least a part of the width of the chamber and each defining the upper limit of an evaporation zone or condensation zone. Each evaporation zone is provided with a fluid vapour outlet and each condensation zone is provided with a fluid vapour inlet. The evaporation and condensation zones operate at different temperatures. The fluid vapour outlet of the evaporation zone operated at the highest temperature is connected to the fluid vapour inlet of the condensation zone operated at the highest temperature, and the fluid vapour outlet of the evaporation zone operated at the lowest temperature is connected to the fluid vapour inlet of the condensation zone operated at the lowest temperature.

Claims

1-27. (canceled)

28. Apparatus for purifying a fluid, comprising an evaporation unit and a condensing unit, wherein the evaporation unit comprises an evaporation unit chamber having upper and lower regions and side walls, a contaminated fluid inlet located in the upper region, a waste outlet located in the lower region and a plurality of vertically-spaced fragmentation plates each spanning at least a part of the width of the chamber and each defining the upper limit of an evaporation zone, wherein each evaporation zone is provided with a fluid vapour outlet, wherein the condensing unit comprises a condensing unit chamber having upper and lower regions and side walls, a condensing fluid inlet located in the upper region, a condensed fluid outlet located in the lower region and a plurality of vertically-spaced fragmentation plates each spanning at least a part of the width of the chamber and each defining the upper limit of a condensation zone, wherein each condensation zone is provided with a fluid vapour inlet, wherein the fluid vapour outlet of the uppermost evaporation zone is connected to the fluid vapour inlet of the lowermost condensation zone, and wherein the fluid vapour outlet of the lowermost evaporation zone is connected to the fluid vapour inlet of the uppermost condensation zone.

29. The apparatus of claim 28, wherein the plurality of evaporation zones are operated at different temperatures with the uppermost evaporation zone being operated at the highest temperature and the lowermost evaporation zone being operated at the lowest temperature, and wherein the plurality of condensation zones are operated at different temperatures with the uppermost condensation zone being operated at the lowest temperature and the lowermost condensation zone being operated at the highest temperature.

30. The apparatus of claim 29, wherein the fluid vapour outlet of the evaporation zone operated at the second highest temperature is connected to the fluid vapour inlet of the condensation zone operated at the second highest temperature.

31. The apparatus of claim 29, wherein the fluid vapour outlet of the evaporation zone operated at the second lowest temperature is connected to the fluid vapour inlet of the condensation zone operated at the second lowest temperature.

32. The apparatus of claim 28, wherein at least one of the fragmentation plates comprises fragmentation means comprising openings through the at least one fragmentation plate.

33. The apparatus of claim 32, wherein the openings are generally circular.

34. The apparatus of claim 33, wherein the openings have an average diameter of about 2 mm.

35. The apparatus of claim 28, wherein at least one of the fragmentation plates comprises a perforated plate or grating.

36. The apparatus of claim 28, wherein at least one of the fragmentation plates comprises a rim around its perimeter provided with a series of notches.

37. The apparatus of claim 36, wherein the height of each notch is no greater than 25% of the height of the rim of the fragmentation plate.

38. The apparatus of claim 28, wherein one or more of the evaporation zones are provided with fragmentation bodies.

39. The apparatus of claim 28, wherein one or more of the condensation zones are provided with fragmentation bodies.

40. The apparatus of claim 28, wherein the evaporation unit chamber further comprises an air inlet located in the lower region of the evaporation unit chamber.

41. The apparatus of claim 40, wherein the condensing unit chamber further comprises an air outlet located in the upper region of the condensing unit chamber.

42. The apparatus of claim 41, wherein the air outlet of the condensing unit is connected to the air inlet of the evaporation unit.

43. The apparatus of claim 28, wherein at least one of the fragmentation plates is substantially horizontal.

44. The apparatus of claim 43, wherein adjusting means are provided to adjust the level of the fragmentation plate.

45. The apparatus of claim 28, wherein each fluid vapour outlet comprises a vapour extractor inclined substantially downwards.

46. The apparatus of claim 45, wherein the mouth of the extractor is on the underside of the extractor.

47. The apparatus of claim 45, wherein the extractor further comprises a rim around the upper edge of the outlet so as to form an overhang protecting the outlet from fluid ingression.

48. Apparatus for purifying a fluid, comprising an evaporation unit and a condensing unit, wherein the evaporation unit comprises an evaporation unit chamber having upper and lower regions and side walls, a contaminated fluid inlet located in the upper region, a waste outlet located in the lower region and a plurality of spaced-apart fragmentation plates each spanning at least a part of the width of the chamber and each defining the upper limit of an evaporation zone, wherein each evaporation zone is provided with a fluid vapour outlet, wherein the condensing unit comprises a condensing unit chamber having upper and lower regions and side walls, a condensing fluid inlet located in the upper region, a condensed fluid outlet located in the lower region and a plurality of spaced-apart fragmentation plates each spanning at least a part of the width of the chamber and each defining the upper limit of a condensation zone, wherein each condensation zone is provided with a fluid vapour inlet, wherein the plurality of evaporation zones are operated at different temperatures from each other and the plurality of condensation zones are operated at different temperatures from each other, wherein the fluid vapour outlet of the evaporation zone operated at the highest temperature is connected to the fluid vapour inlet of the condensation zone operated at the highest temperature, and wherein the fluid vapour outlet of the evaporation zone operated at the lowest temperature is connected to the fluid vapour inlet of the condensation zone operated at the lowest temperature.

49. The apparatus of claim 48, wherein the uppermost evaporation zone is operated at the highest temperature and the lowermost evaporation zone is operated at the lowest temperature, and wherein the uppermost condensation zone is operated at the lowest temperature and the lowermost condensation zone is operated at the highest temperature.

50. A method for purifying a fluid comprising: providing an evaporation unit comprising an evaporation unit chamber having upper and lower regions and side walls, a contaminated fluid inlet located in the upper region, a waste outlet located in the lower region and a plurality of spaced-apart fragmentation plates each spanning at least a part of the width of the chamber and each defining the upper limit of an evaporation zone; providing a condensing unit comprising a condensing unit chamber having upper and lower regions and side walls, a condensing fluid inlet located in the upper region, a condensed fluid outlet located in the lower region and a plurality of spaced-apart fragmentation plates each spanning at least a part of the width of the chamber and each defining the upper limit of a condensation zone; supplying contaminated fluid to the contaminated fluid inlet of the evaporation unit and allowing the contaminated fluid to flow through the evaporation unit chamber to become at least partly evaporated; operating the plurality of evaporation zones at different temperatures from each other and operating the plurality of condensation zones at different temperatures from each other; feeding fluid vapour from the evaporation zone operated at the highest temperature to the condensation zone operated at the highest temperature; feeding fluid vapour from the evaporation zone operated at the lowest temperature to the condensation zone operated at the lowest temperature; supplying condensing fluid to the condensing fluid inlet of the condensing unit and allowing the condensing fluid to flow through the condensing unit chamber resulting in the evaporated fluid becoming at least partly condensed; and extracting the condensed fluid from the condensing unit chamber.

51. The method of claim 50, wherein the uppermost evaporation zone is operated at the highest temperature and the lowermost evaporation zone is operated at the lowest temperature, and wherein the uppermost condensation zone is operated at the lowest temperature and the lowermost condensation zone is operated at the highest temperature.

52. The method of claim 50, further comprising feeding fluid vapour from the evaporation zone operated at the second highest temperature to the condensation zone operated at the second highest temperature.

53. The method of claim 50, further comprising feeding fluid vapour from the evaporation zone operated at the second lowest temperature to the condensation zone operated at the second lowest temperature.

54. The method of claim 50, wherein the evaporation unit chamber further comprises an air inlet located in the lower region of the evaporation unit chamber and the condensing unit chamber further comprises an air outlet located in the upper region of the condensing unit chamber, the method further comprising feeding air from the condensing unit chamber to the evaporation unit chamber.

Description

[0088] The invention will now be further described by way of example only with reference to the accompanying figures in which:

[0089] FIG. 1 is a view in cross section of an evaporation unit of the present invention;

[0090] FIG. 2 is a view down the vertical axis of the chamber of an evaporation unit of the present invention in accordance with a preferred embodiment;

[0091] FIG. 3 is a cross sectional view of the upper part of the evaporation chamber of the embodiment of FIG. 2;

[0092] FIG. 4 is shows a side elevation of part of the rim of a fragmentation plate in accordance with a preferred embodiment;

[0093] FIG. 5 is a view of a fluid purification system of the present invention;

[0094] FIG. 6 is a view in cross section of an evaporation unit in accordance with an alternative embodiment of the present invention; and

[0095] FIG. 7 is a cross sectional view of the mid part of the evaporation chamber showing the air extraction points.

[0096] In FIG. 1, an evaporation unit (10) is shown. The evaporation unit comprises a chamber (12) having a contaminated fluid feed (14) at its upper region (16).

[0097] The chamber (10) is sized to be have a height of 12 metres to allow containerisation allowing ease of transport (in a standard 40 foot container) and fast installation for rapid deployment in emergencies compared to other desalination or fluid treatment systems.

[0098] The top section of the evaporation unit is constructed as a removable module such that the fragmentation bodies (22) and uppermost fragmentation plate (18) can be lifted out of the device for external descaling. The maximum amount of scaling occurs in this uppermost part of the chamber and thus the easy removal of components from that part of the chamber allows external power washing of the packing medium and thus fast, low cost, descaling in an environmentally friendly manner reducing the down time normally associated with this activity.

[0099] The chamber is divided up into five evaporation zones (20) defined at their upper ends by fragmentation plates (18). In the illustrated example, all evaporation zones contain fragmentation bodies (22) for example Raschig rings although the fragmentation body is only shown in the uppermost evaporation zone.

[0100] Acceptable results can be obtained from evaporation units comprising only a single evaporation zone (20), but improved performance is observed when a plurality of evaporation zones (20) are present.

[0101] At the lower region (24) of the chamber (10), a heated air inlet (26) is provided.

[0102] In use, the evaporation unit (10) is fed with warm or hot fluid via feed (14). The fluid (28) is fed onto the upper surface of the uppermost fragmentation plate (18) provided with openings therein. The fragmentation plates (18) present may be circular, square or rectangular in shape, or be of other shapes. The openings in the fragmentation plates may be of variable diameters and be provided in a regular or irregular pattern, or of different sizes and shapes and configurations.

[0103] The hot fluid (28) fed onto the uppermost fragmentation plate (18) flows through the fragmentation openings and generates hot droplets of the liquid, which fall by gravity, through the chamber (10). The drops are further fragmented into smaller droplets by contacting a fragmentation body (22) such as an electrochemically inert random packing material. Such a material may be plastic, ceramic or stainless steel Raschig rings. The choice of fragmentation body depends on the type of fluid to be purified and the operating temperatures. The fragmentation body (22) may be supported by an electrochemically inert support grill which allows the fluid drops to pass into the next section.

[0104] Simultaneously heated air is pumped into the chamber (10) via heated air inlet (26) by fans into the lower region (24) of the chamber (10). The passage of heated air through the hot fluid droplets creates evaporation saturating the air with fluid vapour at varied temperatures.

[0105] The residual concentrated contaminant is collected at the bottom of the chamber for eventual discharge via waste outlet (30).

[0106] In order to maximise evaporation, the air speeds through the evaporation zones (20) are varied by configuring and optimising the heights of each zone (20), thus adjusting the volume that the air/vapour mix must pass through with the same input power from the fan. The variation of air speed thus achieves a similar effect to that of lowering the air pressure at a lower energy cost.

[0107] Fluid which has been evaporated can be removed from the chamber via a series of fluid vapour outlets (32) and are carried away via fluid vapour lines (34). Barriers (36), for example bodies formed of Munters DRIFdek or similar material are placed at the outlets in the chamber (10) to prevent any cross contamination of droplets in the air/gas flow and also to prevent any other possible contamination issues e.g. legionella. As can be seen, each evaporation zone (20) is provided with a vapour fluid outlet (32) at its upper end.

[0108] In FIG. 2, a downward view through the chamber along its vertical axis is provided. In this arrangement, both the chamber (10) and the fragmentation plates (18) are circular. Only the uppermost fragmentation plate (18) is visible as the lower fragmentation plates (18) are positioned directly below the uppermost fragmentation plate (18). In other words, the uppermost fragmentation plate (18) overlaps the lower fragmentation plate (18) completely.

[0109] The fragmentation plates (18) extend partly (but not totally) across the chamber (10) to enable the upflow of heated air. To further facilitate this, the fragmentation plates (18) are provided with a vapour passage (38). The hot fluid is pumped upwards onto the uppermost fragmentation plate from the contaminated fluid feed (14) through a pipe in the base of the fragmentation plate (14). The fragmentation plate is levelled by means of adjusting screws (21) located at 120 spacing around the fragmentation plate. Each fragmentation plate is fitted with such adjusting screws and levelled before use to ensure even distribution of fluid across the cross sectional area of the tower.

[0110] In FIG. 3, a side view of the fragmentation plates (18) is shown illustrating the actual arrangement of the hot fluid inlets into the fragmentation plates (18), and the levelling screws (21). For simplicity only one screw is shown but in practice each fragmentation plate has 3 screws.

[0111] In FIG. 4, a side elevation of part of the side of a fragmentation plate (18) is shown to illustrate the shape of the notches cut along the upper rim to facilitate the hot fluid (28) distribution into the evaporation chamber.

[0112] In FIG. 5, a diagram illustrating operation of the evaporation unit shown in FIGS. 1 to 4 together with a condensing unit of the present invention is provided. The condensing unit is configured similarly to the evaporation unit and corresponding reference numerals preceded by 1 are employed.

[0113] As can be seen, the contaminated fluid fed into the evaporation unit is heated through heat exchange with a heat source (50) which may be a source of waste or exhaust heat from an industrial process, or may be provided by an alternative energy source. Contaminated fluid in the lower region (26) of the evaporating chamber (10) is split out into a contaminated fluid feed (52) of soiled fluid incapable of being recycled which is disposed of and a contaminated fluid feed (54) which is supplemented by a contaminated fluid make up line (60) and heated by heat exchange with fluid exiting the condensing chamber (110) via purified fluid outlet (130). The contaminated fluid feed is then passed back into the evaporation chamber (10) via a heat exchanger (62) and then via contaminated fluid inlet (14).

[0114] Condensation zones (120) within the condensation chamber (110) are fed with fluid vapour extracted from evaporation zones (20). Condensing fluid is fed onto the upper surface of the uppermost fragmentation plate (118) which then fragments and passes through the condensing chamber (110) under gravity. As this fluid passes through the chamber (110), additional fluid condenses from the cooling saturated vapour. This additional purified fluid is then collected in the lower region (124) of the chamber (110) and extracted therefrom via purified fluid outlet (130). In the illustrated device, all condensation zones (120) are filled with fragmentation bodies (not shown) for example Raschig rings.

[0115] Due to the process of condensation, the condensing fluid becomes warmer. This warmed purified fluid is passed via line (56) to a crossflow heat exchanger (64) where the acquired heat is recovered and used to pre-heat the contaminated fluid before being passed to the external heat source (50) for further heating.

[0116] The feed of purified fluid (56) is then split into a purified fluid take off line (58), with the remainder of the purified, now cooled, fluid being passed into the condensing chamber (110) via cooling fluid inlet (114).

[0117] The fluid vapour outlet lines (34) carry the evaporated fluid from specific evaporation zones (20) to the most appropriate condensing zones (120) to maximise evaporation and condensation driven by fans (66). As can be seen, the uppermost evaporation zone (20) which operates at the highest temperature of all of the evaporation zones is connected via line (34) to the lowermost condensation zone (120) which operates at the highest temperature of the condensation zones. The lowermost evaporation zone (20) which operates at the lowest temperature is connected to the uppermost condensation zone (120) which operates at the lowest temperature of the condensation zones. The second hottest (and second highest) evaporation zone is connected to the second lowest (and second hottest) condensing zone, and the second coolest (and second lowest) evaporation zone is connected to the second highest (and second coolest) condensation zone. This system of interconnection can be continued for any number of additional evaporation/condensation zones.

[0118] Condensing chamber (110) is provided with a heated air outlet (126) which carries heated air (which may contain a low amount of fluid vapour) into the evaporation unit via heated air inlet (124).

[0119] FIG. 6 shows an alternative embodiment of the evaporation chamber of FIG. 1, in which fluid vapour outlets (32) are replaced by vapour extractors (32). A side view of the vapour extraction process is shown in FIG. 7. The vapour extractors (32) project partially into the evaporation chamber (10) and are equally spaced around the walls of the chamber. At the end of each extractor (32) there is a drift eliminator (36) to prevent transfer of contaminated fluid droplets. To further prevent such transfers an overhang is fitted to the upper side of the extractor. The vapour extractors discharge into a toroidal shaped duct (37) which is in turn connected to the main duct (34) connecting to the condensation chamber.

EXAMPLE 1

[0120] Evaporation and condensing units configured as shown in FIG. 5, having a height of 12 metres and a diameter of 75 cm, were used to desalinate saline water. The evaporation and condensing units included five evaporation/condensation zones. The sea water input temperature and evaporation zone temperatures were as follows:

TABLE-US-00001 Input Hot Salt Water 85 C. Section 1 (uppermost) 76 C. Section 2 70 C. Section 3 64 C. Section 4 57 C. Section 5 (lowermost) 52 C.

[0121] Results obtained from operating the units under these conditions confirm that a distilled water output over of 18,000 litres per 24 hours is achievable. The water quality was measured using standard conductivity meters and found to have total dissolved solids levels of less than 20 ppm.