Page 371 - Applied Process Design For Chemical And Petrochemical Plants Volume III

66131_Ludwig_CH11A 5/30/2001 4:50 PM Page 328

328 Applied Process Design for Chemical and Petrochemical Plants

Table 11-8 Condensing temperature of refrigerant (propane): 110°F
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Correlation of DuPont SUVA Refrigerant Number Referring to Figure 11-43 at a condensing temperature of 110°F
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with ASHRAE Replacement Numbers and 13°F evaporator temperature: 222 hp/10 Btu/hr of
refrigeration duty
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Product Name Replaces Applications Condenser duty: 1.57 MM Btu/hr/(10 Btu)(hr) of refrigerant
duty.
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SUVA 123 CFC-11 Centrifugal chillers Then, gas hp 35(222) 7,770 hp
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SUVA 124 CFC-114 A/C and refrigeration applica- Condenser duty 35(1.57) 54.95 MM Btu/hr
tions; marine chillers
SUVA 134a CFC-12 Centrifugal and reciprocating Example 11-4. Two-Stage Propane Refrigeration System,
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chillers; medium-temperature 30
Using Charts of Mehra
refrigeration; appliances
New automotive A/C and auto-
Determine the approximate horsepower and condenser
motive service refrigerant
duty for the two-stage system of Figure 11-47. Note: A sim-
SUVA MP39 CFC-12 Service refrigerant for medium-
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pler system omits the sub-cooler and smaller evaporator (see
(R-401A) temperature commercial refriger-
ation; appliances diagram on Figure 11-37).
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SUVA MP66 CFC-12 Service refrigerant for low-
(R-401B) R-500 temperature commercial and Refrigeration load of processing cooling:
transport refrigeration (25 10 4) MM Btu/hr
SUVA HP62 R-502 All commercial refrigeration Refrigerant evaporating temperature: Consider the 25MM
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(R-404A) Btu/hr @ 40°F independently as a simple two-stage system.
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SUVA HP80 R-502 Service refrigerant for all Thus, condensing at 120°F
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(R-402A) commercial refrigeration Duty 1.71 MM Btu/hr/(10 Btu/hr), see Figure 11-46. Using
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SUVA HP81 R-502 Ice machines and other medium- Figure 11-45, read the gas hp/10 Btu/hr at evaporator of
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(R-402B) temperature equipment 40°F and refrigerant condensing temperature of 120°F
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SUVA 9000 HCFC-22 An equivalent pressure 279 hp/(10 Btu)(hr)
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(R-407C) replacement for HCFC-22 with 0 Combining the second refrigeration load of 10 MM Btu/hr and
ozone depletion potential for use 25°F and the refrigerant subcooler duty of 4 MM Btu/hr as
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in commercial and residential air a single-stage system using Figure 11-43: 143.5 hp/10 Btu/hr
conditioners and heat pumps. refrigerant duty condensing at 120°F. From Figure 11-44
Suva 9000 provides the closest at an evaporator temperature of 25°F and a condensing
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match to HCFC-22 performance temperature of 120°F,
in existing HCFC equipment
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design. Condenser duty 1.366 MM Btu/hr/(10 Btuhr).
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SUVA 9100 HCFC-22 A high pressure replacement for
(R-410A) HCFC-22 with 0 ozone depletion The total horsepower and condenser duty are the sums
potential in new HCFC equipment for each stage of the system. Then,
SUVA 95 R-503 Non-ozone-depleting replacement
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(R-508B) CFC-13 for R-503 and CFC-13 in very low-
Gas hp (25)(279) (10 4)(143.5) 7,836 hp
temperature applications (less
Condenser duty (25)(1.71) (10 4)(1.366)
than 40° F)
50.95 MM Btu/hr
For more information, call 1-800-235-SUVA.
Hydrocarbon Mixtures and Refrigerants
Used by permission: Bul. H-50267-2, ©1996. DuPont Fluoroproducts
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Suva Refrigerants.
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Many gas processing and hydrocarbon cracking and
petroleum processing plants have large quantities of hydro-
(Text continued from page 321)
carbon mixtures (such as propane-butane, propane propy-
lene, ethylene-ethane, ethylene-propylene, etc.) available
and these mixtures can be used as refrigerants in properly
Example 11-3. Single-Stage Propane Refrigeration System,
designed systems. For proper operation of the compressor,
Using Charts of Mehra 30
condenser, and evaporator in these systems, it is extremely
important to maintain uniform compositions (avoiding
Determine the approximate horsepower and condenser
leaks and random make-up additions of hydrocarbon) and
duty for a single-stage propane refrigeration system (see flow
to use only two hydrocarbons in the refrigerant mix, rather
diagram of Figure 11-43).
than three or more, as the operation can become quite com-
plicated otherwise. Even for a mixture high in composition
Refrigeration load of process cooling: 35 MM Btu/hr
Refrigeration evaporating temperature: 13°F
Temperature of process fluid: 10°F (Text continued on page 333)