major project - review iv.ppt

MAJOR PROJECT

CH4092

REVIEW IV

PROJECT TITLE: DESIGN AND FABRICATION OF DESALINATION PLANT USING HUMIDIFICATION DEHUMIDIFICATION CYCLE

PROJECT GUIDE: Dr. LITY ALEN VARGHESE

GROUP MEMBERS: A ARUN - B100905CH

A J JITHIN - B101008CH

JISHNU SIVADASAN - B100933CH

ADARSH CHANDRAN - B100951CH

The humidifier is a packed bed humidification tower.

FABRICATION OF HUMIDIFIER


PACKING Highly heat resistant inch 0.5 PVC pipes were cut into small pieces to give an l/d ratio of 1.5.

These offer packing properties similar to that of raschig rings.


PACKING This was chosen taking into account the low pressure drop they offer, sea water resistant properties, low cost factors.

Packing was filled to a height of 0.95 metre (on the basis of theoretical calculation made earlier).


SHELL Shell consists of a G.I pipe of diameter 80 mm and height 1.2 metre.

GI pipe was chosen solely on the basis of availability.


SHELL


LIQUID DISTRIBUTOR PLATE

Consists of a 15×15 cm square plate made of mild steel which also acts as a flange.

Mild steel was chosen for ease of machining in the Mechanical Workshop, NIT – C.



It has 52, 6 mm holes drilled in a circular region that which the shell encompasses to give a free area of 30%.

These holes ensure that the feed get evenly distributed and that there is no channeling.


PACKING HOLD DOWN PLATE

Consists of a 15×15 cm square plate made of mild steel which also acts as a flange.

Mild steel was chosen for ease of machining in the Mechanical Workshop, NIT – C.



Their primary function is to support the weight of packing and liquid hold up.

It has 39, 8 mm holes drilled in a circular region that which the shell encompasses to give a free area of 36%.



These holes ensure that the feed get evenly distributed and that there is no channeling.


NOZZLES 2 nozzles each were welded to a section consisting of a GI of diameter 3 inch and length 10 cm.

These sections were closed on one side by welding packing hold down and liquid distributor plate respectively.


NOZZLES The other two nozzles were welded separately to the curved surface area of each section.

The nozzles were made of GI pipes of diameter 0.5 inch and length 5 cm.


NOZZLES

fABRICATION OF DEHUMIDIFIER The dehumidifier is a double pipe heat exchanger with an U-

bend.


INNER PIPE The inner pipe consists of two MS pipes 1.5 m long and 2 inch diameter joined by an U – bend.

26 triangular fins made of GI sheet was partially inserted into the inner pipe at a distance of 10 cm between alternatively from opposite ends.


INNER PIPE This will result in more residence time and hence better heat transfer.

The flow pattern within the pipe will be as shown below:


INNER PIPE


OUTER PIPE The outer pipe was made of 2 PVC pipes connected by an U – bend, each 1.5 m long and of diameter 5 inch.

PVC was chosen to avoid external heat losses to the environment.


OUTER PIPE The portion of the triangular fins that extend out of the inner pipe enhance heat transfer.


OUTER PIPE

EXPERIMENTAL SET-UP

PROCESS FLOW DIAGRAM

EXPERIMENTAL RESULTS – (FIXED FLOWRATE)

Air Flowrate (lph)

Water feed (lph) Electric heat duty (W)

Tin (⁰C) Tout (⁰C) Fresh water obtained

(lph)

100 242.58 503.27 55.2 78.15 3.98

120 240.49 436.51 51.6 74.8 3.88

140 241.37 405.61 49.3 73.3 3.79

160 245.01 415.72 47.5 72.0 4.01

180 244.52 420.56 47.1 71.7 3.99

COMPARISON OF THEORETICAL vs

EXPERIMENTAL RESULTS

CONCLUDING POINTS A Humidification – Dehumidification Desalination pilot plant

has been designed and fabricated.

Fresh water of approx. 4 LPH has been obtained using approx. 250 LPH sea-water.

140 LPH has been found out as the optimum flow rate of air.

Thus, it can be concluded that HDD is a feasible solution to world’s water woes, both technically and economically.

major project - review iv.ppt

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