For this proposed design, 4500 kg/h of ammonia vapor at 6.7 bara pressure is to be cooled from 120°C to 40°C, using cooling water. The maximum supply temperature of the cooling water available is 30°C, and the outlet temperature is to be restricted to 40°C. The pressure drops over the exchanger must not exceed 0.5 bar for the ammonia stream and 1.5 bar for the cooling water.

A contractor has proposed using a shell and tube exchanger with the following specification for this duty.

Shell: E-type, inside diameter 590 mm. 

Baffles: 25% cut, 300 mm spacing. 

Tubes: carbon steel, 15 mm inside diameter, 19 mm outside diameter, 2400 mm long, number 360. 

Tube arrangement: 8 passes, triangular tube pitch, pitch 23.75 mm. 

Nozzles: shell 150 mm inside diameter, tube headers 75 mm inside diameter.

It is proposed to put the cooling water though the tubes. 

Is the proposed design suitable for the duty?

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Physical properties of ammonia at the mean temperature of 80°C: specific heat 2.418 kJkg-¹°C-1, thermal conductivity 0.0317 Wm-¹°C-1, density 4.03 kg/m³, viscosity 1.21 x 10-5 Nm-²s.