Page 334 - Applied Process Design For Chemical And Petrochemical Plants Volume III

66131_Ludwig_CH11A 5/30/2001 4:49 PM Page 293

Refrigeration Systems 293

indirect for heat exchangers or similar equipment. Water for
a once-through system need only be as free from impurities as
its use and reasonable corrosion conditions require; whereas
the recirculated water is usually condensate (with condensate
make-up) with blow-down or treatment to avoid solids or
other contaminant build up. The principles of design and
selection are the same for the two types.

Capacity

Heat load of process per hr
Tons of refrigeration required
12,000 Btu>hr.
(11-1)

†

Figure 11-4. (Above and below) Barometric-type condenser,
steam jets with two boosters. (Used by permission: ©Ingersoll-Rand
Company.)
† Based on required N.P.S.H. of pump. May be reduced by pump pit or
by pump requiring less N.S.P.H.

Figure 11-3. Water-vapor relationship in steam jet refrigeration unit.

Tons* of
No. of Refrig. Approximate Dimensions
Boosters at 50°F A B C D E
1 30 46 ft-0 in. 4 ft-6 in. 6 ft-0 in. 8 ft-6 in. 5 ft-0 in.
1 40 48 ft-6 in. 4 ft-6 in. 6 ft 6 in. 9 ft-0 in. 5 ft-0 in.
1 50 48 ft-6 in. 4 ft-6 in. 6 ft 6 in. 9 ft-0 in. 5 ft-6 in.
2 60 50 ft-0 in. 4 ft-6 in. 9 ft 6 in. 9 ft-6 in. 6 ft-0 in.
2 80 51 ft-0 in. 4 ft-6 in. 9 ft 6 in. 10 ft-6 in. 6 ft-6 in.
2 100 52 ft-0 in. 5 ft-6 in. 10 ft 6 in. 11 ft-0 in. 7 ft-0 in.
2 125 53 ft-0 in. 5 ft-6 in. 12 ft 0 in. 12 ft-0 in. 7 ft-6 in.
2 160 54 ft-0 in. 5 ft-6 in. 13 ft 0 in. 13 ft-0 in. 8 ft-0 in.
3 200 56 ft-0 in. 5 ft-6 in. 12 ft 6 in. 14 ft-6 in. 9 ft-0 in.
3 250 57 ft-6 in. 6 ft-0 in. 13 ft 6 in. 15 ft-6 in. 10 ft-0 in.
4 320 60 ft-0 in. 6 ft-0 in. 13 ft 0 in. 17 ft-6 in. 11 ft-6 in.
4 400 62 ft-6 in. 7 ft-0 in. 14 ft 0 in. 18 ft-6 in. 12 ft-0 in.
*See Figure 11-7 for estimating capacities at other temperatures.