Inclined plate settlers

Transcription

1 IPS Inclined plate settlers Compact thickening and clarification, reduced retention time

2 IPS Inclined plate settlers Metso s inclined plate pack principle uses several parallel inclined plates to maximise the available area for any available floor area. In this way, the size and cost of the gravity settler can be minimized by matching the thickening and clarifying requirements more closely. The two basic criteria for gravity settling equipment are good clarity of the over flow liquid and maximum density of the underflow solids discharge. The area required to clarify a suspension is often greater than that needed for thickening. This means that in a cylindrical thickening tank, the lower section with rakes and drive mechanism can be oversized. The inclined plate pack principle uses several parallel inclined plates to maximise the available settling area for any available floor area. In this way, the size and cost of the gravity settler can be minimized by matching the clarifying and thickening requirements more closely. Particles between Fl the inclined plates migrate to each plate surface along the resultant vector of the two forces - fluid drag (Fl) and gravity (Fg). Fg Once on the plates, the particles slide down to discharge into the thickening zone. 2 Sedimentation equipment

3 Overflow launders Rake lift (optional) Flocculation agitator Overflow outlet Feed inlet Flocculation agitator Inclined plate pack Sludge hopper Rake with drive unit Underflow outlet Inclined Plate Settler The Inclined Plate Settler (IPS) consists of two main components, the upper tank containing the plate packs inclined at 55 and the lower conical or cylindrical sludge tank. The feed for the IPS enters through vertical chambers on either side of the plate packs and passes into each plate gap through slotted feed ports. Clarification takes place above the suspension inlet so there is no mixing of the clarified fluid with the incoming feed. Above each pack is a full-length overflow launder fitted with throttling holes to create a slight hydraulic back pressure on the incoming feed stream. This method of feed control guarantees equal distribution to all inclined plate pack chambers with minimum turbulence at the entry points. The solids settle onto and slide down each plate pack to the sludge tank where the solids are further thickened and compressed with the assistance of the raking system. Sedimentation equipment 3

4 Advantages Heavy duty construction of tank, sludge hopper and inclined plate pack, as well as the rake system. Rake lifting mechanism as option Positioning of specifically designed feed ports for optimum ratio between clarification and thickening area Wide spacing of inclined plates to handle high density feed pulps and coarse solid particles No short circuiting or surface turbulence Integrated flocculator with variable speed stirrer Lower installation costs Delivered as one-piece unit or in prefabricated sections Smaller foundations Less floor space Square outline for easier planning and construction Flexibility for plant changes or extensions Can be installed in any system Easy to relocate to adapt to process changes Simplified in-plant installation Shorter pipework runs High level installation for gravity feed to downstream processes Easier supervision Small internal volume and surface area Easily insulated against heat loss or toxic fume emissions Evaporative losses are minimized. Simple construction of sheet steel and standard profiles Special materials and coatings can easily be incorporated Easy to maintain 4 Sedimentation equipment

5 Model LTO The LTO model is designed for total projected settling areas of 15 to 500m 2 and is suitable for the following applications: Small to medium solids flow rate Slurries containing coarse fractions Options: Extended sludge hopper Flocculator with variable drive stirrer Automatic rake lifting device Automatic underflow control Model LTS The LTS model combines a circular sludge tank and rake mechanism with the clarification capability of the LT inclined plate pack system in a single compact unit. The rakes, together with the larger sludge tank, give: Increased sludge thickening capacity Positive sludge discharge Greater sludge storage and surge capacity Model LTK The LTK is similar in design to the LTS model but is fitted with a larger diameter sludge tank. The LTK model is used when long retention times are required to achieve the required underflow density and the solids loading is beyond the range of the LTS unit. Sedimentation equipment 5

6 Model LTC The LTC model consists of a number of inclined plate packs installed in a conventional cylindrical thickener tank with a standard centre-drive rake mechanism to remove the thickened sludge. The compact prefabricated plate packs of the LTC design allows the use of very large clarification areas installed in a fraction of the floor area required for a conventional thickener without inclined plate packs. The LTC system allows a substantial reduction in the overall investment cost. In some applications, the LTC can also be used as a classifier; changing the number of plate packs in use varies the classification cut point. LTC inclined plate packs can also be fitted to existing thickeners and clarifiers in order to enlarge the useful clarification area. This also applies to rectangular clarification basins. Model LTE For higher thickening rates and greater sludge buffer capacity, Metso now offer a specially modified system. The LTE model has a cylindrical tank mounted on a concrete foundation. The heart of the system is the plate packs which gives maximum clarification area from minimum floor space. This could minimise or eliminate the need for flocculants. Waste water or slurry streams from sand and gravel washing plants, soil treatment plants, coal plants and other mineral processing systems can be cleaned advantageously using the model LTE, returning clean water to the treatment process. The LTE model can also be delivered with a conical sludge hopper used at lower solid loads or for coarser particles. This model, the LTE/C has the same upper section and settling area as the LTE model. The IPS plants which use these machines in combination with appropriate dewatering systems are described in separate technical bulletins. 6 Sedimentation equipment

7 Technical data LTO LTS LTK L W L W L W A A A H H H Model H (max) L W A Total volume Sludge volume Flocculator volume Weight empty mm (ft) mm (ft) mm (ft) mm (ft) mm 3 (ft 3 ) mm 3 (ft 3 ) mm 3 (ft 3 ) kg (lbs) LTO (11.4) (8.7) (4.4) (5.9) 4.6 (162) 1.1 (39) 0.8 (28) (3 968) LTO (14.1) (11.3) (6.0) (5.9) 9.2 (325) 2.3 (81) 0.8 (28) (7 716) LTO (15.3) (12.7) (7.3) (5.9) 16.2 (572) 4.2 (148) 2.0 (71) (10 582) LTO (17.7) (14.8) (9.4) (5.9) 28.7 (1 014) 9.4 (332) 3.0 (106) (17 196) LTO (19.5) (18.2) (10.2) (5.9) 41.5 (1 466) 14.5 (512) 4.0 (141) (23 149) LTO (21.3) (18.8) (12.1) (5.9) 54.6 (1 928) 18.8 (664) 5.0 (177) (29 101) LTO (26.6) (22.7) (14.8) (6.6) (3 736) 47.8 (1 688) 7.0 (247) (53 572) LTO (28.3) (25.6) (19.0) (6.6) (5 679) 72.8 (2 571) 8.0 (283) (87 082) LTS (12.3) (8.7) (4.4) (5.91) 5.2 (184) 1.7 (60) 0.8 (28) (4 409) LTS (15.2) (11.3) (6.0) (5.91) 11.1 (392) 4.2 (148) 0.8 (28) (8 157) LTS (15.4) (12.7) (7.3) (5.91) 18.6 (657) 6.6 (233) 2.0 (71) (11 244) LTS (16.8) (14.8) (9.4) (5.91) 32.5 (1 148) 13.2 (466) 3.0 (106) (18 960) LTS (17.4) (18.2) (10.2) (5.91) 45.8 (1 617) 18.8 (664) 4.0 (141) (24 912) LTS (20.0) (18.8) (12.1) (5.91) 61.8 (2 182) 26.0 (918) 5.0 (177) (34 833) LTS (20.3) (22.7) (14.8) (6.56) (4 026) 56.0 (1 978) 7.0 (247) (50 706) LTS (21.0) (25.6) (19.0) (6.56) (5 403) 65.0 (2 295) 8.0 (283) (79 366) LTK (16.7) (9.2) (5.3) (5.9) 8.0 (283) 4.5 (159) 0.8 (28) (4 850) LTK (14.9) (12.11) (7.6) (5.9) 14.5 (512) 7.6 (268) 0.8 (28) (9 921) LTK (15.7) (13.7) (9.2) (5.9) 23.5 (830) 11.5 (406) 2.0 (71) (13 669) LTK (17.7) (16.5) (12.2) (5.9) 45.5 (1 607) 26.2 (925) 3.0 (106) (22 267) LTK (19.0) (19.3) (14.7) (5.9) 61.0 (2 154) 34.0 (1 201) 4.0 (141) (28 660) LTK (21.3) (20.6) (15.5) (5.9) 87.0 (3 072) 51.2 (1 808) 5.0 (177) (36 376) LTK (22.7) (24.6) (20.4) (6.6) (5 050) 85.0 (3 002) 7.0 (247) (58 422) LTK (22,8) (28,6) (24,7) (6,6) (7 063) (3 955) 8.0 (283) ( ) Heavy duty IPS with radially placed inclined plate pack. Prefabricated inclined plate pack Sedimentation equipment 7

8 The Metso Way Making the big difference to our customers Everything we do is based on deep industry knowledge and expertise that makes the big difference to our customers. Decades of close customer collaboration and adapting to our customers ever changing needs have transformed us into a knowledge company. minerals.info@metso.com Subject to alteration without prior notice Brochure No ESBL/Sala-English 2016 Metso