menu
bartleby
search
close search
Hit Return to see all results

*"24.27 In the vapor-recompression evaporator shown in Figure P24.27, the vapor producedon evaporation is compressed to a higher pressure and passed through the heating coilto provide the energy for evaporation. The steam entering the compressor is 98%vapor and 2% liquid, at 10 psia; the steam leaving the compressor is at 50 psia and400°F; and 6 Btu of heat are lost from the compressor per pound of steam throughputThe condensate leaving the heating coil is at 50 psia, 200°F(a) Compute: The Btu of heat supplied for evaporation in the heating coil per Btu ofwork needed for compression by the compressor.(b) If 1,000,000 Btu per hour of heat is to be transferred in the evaporator, what mustbe the intake capacity of the compressor in ft3 of wet vapor per minute?CompressorO00040Heating CoilFigure P24.27Condensate

Question
*"24.27 In the vapor-recompression evaporator shown in Figure P24.27, the vapor produced
on evaporation is compressed to a higher pressure and passed through the heating coil
to provide the energy for evaporation. The steam entering the compressor is 98%
vapor and 2% liquid, at 10 psia; the steam leaving the compressor is at 50 psia and
400°F; and 6 Btu of heat are lost from the compressor per pound of steam throughput
The condensate leaving the heating coil is at 50 psia, 200°F
(a) Compute: The Btu of heat supplied for evaporation in the heating coil per Btu of
work needed for compression by the compressor.
(b) If 1,000,000 Btu per hour of heat is to be transferred in the evaporator, what must
be the intake capacity of the compressor in ft3 of wet vapor per minute?
Compressor
O00040
Heating Coil
Figure P24.27
Condensate
help_outline

Image Transcriptionclose

*"24.27 In the vapor-recompression evaporator shown in Figure P24.27, the vapor produced on evaporation is compressed to a higher pressure and passed through the heating coil to provide the energy for evaporation. The steam entering the compressor is 98% vapor and 2% liquid, at 10 psia; the steam leaving the compressor is at 50 psia and 400°F; and 6 Btu of heat are lost from the compressor per pound of steam throughput The condensate leaving the heating coil is at 50 psia, 200°F (a) Compute: The Btu of heat supplied for evaporation in the heating coil per Btu of work needed for compression by the compressor. (b) If 1,000,000 Btu per hour of heat is to be transferred in the evaporator, what must be the intake capacity of the compressor in ft3 of wet vapor per minute? Compressor O00040 Heating Coil Figure P24.27 Condensate

fullscreen
check_circleAnswer
Step 1

Part (a)

 

The schematic flow diagram for the given process is shown below. Let the system be considered as steady state open system so that there is no accumulation of energy within the system. Also, the change in kinetic and potential energy for the system is taken as 0. H1, V1, H2, V2, and H3 are taken at the specified conditions from  the steam tables available.

State 2
Heat lost
State 3:
H3 168.1 Btu/Ib
50 psia, 200 F
Condensate
6 Btu/lb
H 1235 Btu/lb
V2 10.067 ft/1b
50 psia, 400°F
Compressor
Heating coil
State 1
Hi 1123.42 Btu/Ib
Vi 37.675 ft/lb
98% V, 2% L, 10 psia
Evaporator
help_outline

Image Transcriptionclose

State 2 Heat lost State 3: H3 168.1 Btu/Ib 50 psia, 200 F Condensate 6 Btu/lb H 1235 Btu/lb V2 10.067 ft/1b 50 psia, 400°F Compressor Heating coil State 1 Hi 1123.42 Btu/Ib Vi 37.675 ft/lb 98% V, 2% L, 10 psia Evaporator

fullscreen
Step 2

Calculate the change in enthalpy from state 1 to state 2 as shown. Also, the heat lost from the compressor is given as, Q = -6 Btu/lb. Thus, the work done by the steam is calculated as shown below. Note that work done by the compressor is negative of the work done by the steam.

дн — Н, - Н,
1235-1123.42
=111.58 Btu/lb
и -о-Ан.
=-6-111.58
=-117.58 Btu/lb
help_outline

Image Transcriptionclose

дн — Н, - Н, 1235-1123.42 =111.58 Btu/lb и -о-Ан. =-6-111.58 =-117.58 Btu/lb

fullscreen
Step 3

The heat lost for the heating coil is calculated as shown below. The negative value ...

0-дн
— Н, - н.
2-3
= 168 -1235
:-1067 Btu/lb
help_outline

Image Transcriptionclose

0-дн — Н, - н. 2-3 = 168 -1235 :-1067 Btu/lb

fullscreen

Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Our solutions are written by experts, many with advanced degrees, and available 24/7

See Solution
Tagged in

Engineering

Chemical Engineering

Chemical Engineering

Related Chemical Engineering Q&A

Find answers to questions asked by student like you

Show more Q&A add
question_answer

Q: 500 kg/hour of a mixture containing 10wt% methane and 90wt% ethane at 27°C and 1 bar is fed to a mix...

A: The flowchart for the given process is shown below.Here, ṁ3 kg/h is the flowrate of the product stre...

question_answer

Q: Determine the specific potential energy change that water undergoes when a mass of water is raised 4...

A: Specific potential energy is the potential energy of 1 unit mass of the object. Change in specific p...

question_answer

Q: The inner pipe of a double-pipe heat exchanger has an OD of 1.9 in. and contains 36 rectangular fins...

A: Note: Since we only answer up to 3 sub-parts, we’ll answer the first 3. Please resubmit the question...

question_answer

Q: Homework #1 1.18 Nitrogen gas can be injected into oil wells to increase the recovery of crude oil (...

A: Part (a)Note: As the table 1.2 and 1.3 was not provided with the question so, conventional symbols a...

question_answer

Q: Please answer part (g) only.

A: Part g:The part can be solved in two ways:Apply final value theorem and find the ultimate value of t...

question_answer

Q: The surface temperature of the electronic chip shown below is 75C and it is surrounded by ambient a...

A: The area of the upper surface of the chip carrier is calculated as:

question_answer

Q: Fuels for motor vehicles other than gasoline are being eyed because they generate lower levels of po...

A: Combustion reaction of propane with air is written as:Note that in the question CO2 and CO are given...

question_answer

Q: All details in question, please show all steps

A: Part (a)Michaelis-Menten equation to be used is written as equation (1).The reciprocal equation of (...

question_answer

Q: Hi this is what it can help please provide the explanation for solutions don’t worry about the  exac...

A: Given dataPressure of the system (P) = 145 psigTemperature of the system (T) = 70oFCritical pressure...

Sorry about that. What wasn’t helpful?