2008 02 Bulletin Timisoara

7/26/2019 2008 02 Bulletin Timisoara

1/5

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/274648427

Criteria for the vapor space design in kettlereboilers

Article December 2008

CITATION

1READS

379

4 authors:

Branislav Milenko Jacimovic

University of Belgrade

41PUBLICATIONS 123CITATIONS

SEE PROFILE

Srbislav Genic

University of Belgrade - Faculty of Mechani


SEE PROFILE

Nikola J. Budimir

University of Belgrade


SEE PROFILE

Marko S. Jari


SEE PROFILE

All in-text references underlined in blueare linked to publications on ResearchGate,

letting you access and read them immediately.

Available from: Marko S. Jari

Retrieved on: 07 June 2016
https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_1https://www.researchgate.net/?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_1https://www.researchgate.net/profile/Marko_Jaric?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_7https://www.researchgate.net/profile/Marko_Jaric?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_5https://www.researchgate.net/profile/Marko_Jaric?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_4https://www.researchgate.net/profile/Nikola_Budimir?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_7https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/profile/Nikola_Budimir?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_5https://www.researchgate.net/profile/Nikola_Budimir?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_4https://www.researchgate.net/profile/Srbislav_Genic?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_7https://www.researchgate.net/profile/Srbislav_Genic?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_5https://www.researchgate.net/profile/Srbislav_Genic?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_4https://www.researchgate.net/profile/Branislav_Jacimovic?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_7https://www.researchgate.net/institution/University_of_Belgrade?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_6https://www.researchgate.net/profile/Branislav_Jacimovic?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_5https://www.researchgate.net/profile/Branislav_Jacimovic?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_4https://www.researchgate.net/?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_1https://www.researchgate.net/publication/274648427_Criteria_for_the_vapor_space_design_in_kettle_reboilers?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_3https://www.researchgate.net/publication/274648427_Criteria_for_the_vapor_space_design_in_kettle_reboilers?enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ%3D%3D&el=1_x_2


2/5

297

SCIENTIFIC BULLETIN OFTHE POLITEHNICA UNIVERSITY OF TIMISOARA, ROMANIA

TRANSACTIONS ON MECHANICSBULETINUL TIINIFIC AL

UNIVERSITII POLITEHNICA DIN TIMIOARA, ROMNIASERIA MECANIC

Tom 53 (67) ISSN 1224 - 6077 Fasc. S2, 2008

CRITERIA FOR THE VAPOR SPACE DESIGN IN

KETTLE REBOILERSBranislav JACIMOVIC*, Srbislav GENIC*, Nikola BUDIMIR**, Marko JARIC**

*Department of Process Engineering, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16,11000 Beograd, Serbia,[email protected], [email protected]

**Innovation Center of the Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11000Beograd, Serbia, [email protected], [email protected]

Abstract. There are several design criteria concerning the dimensions of the vapor space in kettle reboilers. Thesecriteria are listed and commented in this article. An numeric example illustrates the usage of this criteria.

Keywords:kettle reboiler, vapor space, liquid entrainment

1. IntroductionThe most commonly used type of evaporator

in refining industry is a kettle reboiler.

This kind of reboiler is often used in many

other industries (refrigeration systems, distilled

water production, desorption systems, etc.). Kettle

reboiler consists of either a U-tube bundle or

floating head tube bundle inserted into an

enlarged shell.

The shell provides disengaging space(volume) for the vapor separation of liquid

droplets. Liquid level in shell is usually controlled

by level controller or simply held by the weir. The

hot fluid in this kind of apparatus flows inside the

tubes. Generally speaking the size (diameter) of

the kettle reboiler shell depends on the vapor and

liquid flow rates, their physical properties and the

exchanger geometry. It must be noted that if dry

vapor is really required, as in the case of a

compressor feed, additional protection, such as

mechanical mist eliminators, is needed.

There are several design criteria that can befound in the open literature sources. Further on

these criteria are listed and commented.

2 Design criteriaTwo phase flow of vapor/liquid mixture in

disengagement space in kettle reboilers is

complex. Although several authors tried to

develop the adequate mathematical model, it can

be said that nowadays the design is still based on

the empirically gathered information. Design

criteria can be grouped in the following manner.

2.1 Criteria based on the simple geometryratiosPalen [2] suggests that the distance from the

centerline of the uppermost tube in a horizontal

bundle to the top of the shell should not be less

than 40% of the kettle shell diameter

.4.1/ bs DD

mm052

The freeboard between the liquid level and shell

should be at least =sH

mm300

[1], [9].

For practical reasons (better separations of

entrainment) liquid level at kettle horizontal

reboilers settings that one or two upper rows oftubes does not in liquid [2]. In these cases the

height of the vapor space should be at least

=sH .
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


3/5

298

In [1] and [9] the required shell diameter is

defined as the function of the heat flux.

Summarizing the data from both references the

following equation can be formed

( ) q 025.0

2kW/mD

D

b

s += 015.01 (1)

where is in .q

2.2 Criteria based on the volume of the vaporspaceThe role of the vapor space is to separate the

mixture of liquid and vapor.

In [11] for steam boilers at the atmospheric

pressure, the following equation is given

5,101.0

011.0

sepH+14.0G

V

V+=

&

(2)

In [10] this equation is recommended for kettle

reboilers with drop eliminators (figure 1). For

pressures other than 1 bar the right side of

equation should be multiplied with

22,022 p

p

,1=f (3)

for absolute pressure in range 0.55 bar.

Hsep

Vapor

Figure 1 Cross section of the vapor space

According to Palen [2] the minimal vapor volume

should be

GL

G

V

V= 5,80& (4)

2.3 Criteria based on the Souders - BrownequationThe most commonly cited reference is based on

Souders-Brown equation in the form

1G

LK

=G,maxw (5)

In [1] and [9] it is said that the entrainment

coefficient K ranges between 0.03 m/s and 0.09m/s.

If the kettle reboiler is connected with distillation

column the entrainment coefficient ( K) is

estimated by the relation from [5]25.0

33.014.3

=

GL

eK

(6)

Specific entrainment (carryover of the liquid with

vapor phase) shouldnt be above 2%, or can be

found by the

0

11

1

1

=

=

eG

L

e Em

m

fe

&

& (7)

where

0

0

=

= =

e

ae

eE

EEf

2LL w

Pa10002


4/5

299

bs DD /

mm260=sepH

2m9.63=2kW/m39.

18.111.

4.1

=1.59 and the height of the separation

space is

Heat power of the apparatus is 472 kW (ammonia

flow rate is 1194 kg/h), and the heat transfer

surface is , that provides heat flux

. Using equation (1) the

diameter ratio should be 1 or

according to Palen

S

7=q

=bs DD /

/ =bD

m/s03.0=

maxGw ,

Gw

21=max

m/s03.0=

0013.0

sD .

Accordingly to (5) using the

maximal vapor velocity should be =0,889

m/s. Real vapor velocity is =0,110 m/s, so

. If the equation (6) is used

to obtain the entrainment factor is ,

the corresponding value of specific entrainment is

K

%4,/ ,GG ww

K

, which is way beyond usually adopted=e02.0=e

3m0.798=

3m0.858=

mm5500=bL

5.2

.

According to Palens equation (4) minimal volume

of the vapor space is V , and this value

is by 8% lesser than the real V .

Since the bundle length is , the

minimal number of nozzle pairs is =NN

m/s5.26, =outGw

Pa5492 , = outGG w

.

The outlet vapor velocity is

and the

It can be concluded that all of the design

criteria noted in the this article are satisfied.

Figure 2 Kettle horizontal reboiler (all dimensions in millimeters) A- inlet of process fluid, B-outlet of

process fluid, C-inlet of ammonia, D-outlet of vapor ammonia

4. ConclusionThere are several design criteria in open literature

concerning the dimensions of the vapor space in

kettle reboilers. These criteria (recommendations)

are listed in this article, so the design procedurecan be easily formed. The procedure is

demonstrated on kettle reboiler that condenses

CO2 at the tube side, using ammonia as a cold

fluid.

5. Nomenclaturem,sD

m,bD

0=e

, diameter

, tube bundle diameter

E , tray efficiency at zero entrainment

aE

mm,sepH

bssep DDH =

m,bL

kg/s,m&

N

N

bar,p

W,Q

2W/m,q

2m,S

3m,V

m/s,w

3kg/m,

N/m,

, apparent tray efficiency

, the height of the separation zone

m/s,K , the entrainment coefficient

, length of tube bundle

, mass flow rate

, number of pairs (inlet plus outlet) of nozzles

, pressure in vapor space

, heat power

, heat flux

, heat transfer surface

, vapor volume

, velocity

Greek

density

surface tension

Indexes


5/5

300

max, maximalmin, minimalmix, mixtureG, gas (vapor)

L, liquidout, outlet

6. References1. Sinnott R. K.: Chemical Engineering Volume 6:

Chemical Engineering Design, Pergamon Press,Oxford, 1983.

2. Palen J. W. Small W. M.:A New Way to DesignKettle and Internal Reboilers, HydrocarbonProcessing, V. 43, No. 11, p. 199 1964.

3. Vujic, S..: Colling Devices[in Serbian], Facultyof Mechanical Engineering, Belgrade, 1997.

4. *** Iranian Petroleum Standards IPS-E-PR-880,Engineering Standard For Process Design Of

Gas (Vapor)-Liquid Separators, May 1997.5. Tammami B., Simplifying reboiler entrainment

calculations, Oil Gas Journal, June 1985.6. Heat Exchanger Design Handbook (HEDH)

Volume 3, Hemisphere Publishing Company,Washington, 1986.

7. Jacimovic B., Genic S.: The Study Of The

Revitalization Of The CO2Production FascilityIn Becej Serbia [in Serbian], Belgrade 2007.

8. ***Standards of Tubular ExcangersManufactures Association, Sixth Edition, NewYork 1978.

9. Ernest L.:Applied Process Design for Chemicaland Petrohemical Plants, Volume 3, Third

Edition, Gulf Professional Publishing, Boston

1999.10. Billet, R.: Evaporation Technology, VCH

Verlagsgesellscahft mbH, Weinheim, 1989.11. Vorkauf, H., Forschung auf dem Gebiet des

Ingenieurwesens, VDI Forschungsheft B341,

1931.12. ***Engineering standard for process design of

gas (vapour)-liquid separators, original editionMay 1997. Iranian Petroleum Standard IPS-E-PR-880.

RELAIA CRITERIALPENTRU

DIMENSIONAREA SPAIULUI DE VAPORIDIN CAZANUL DE ABUR TIP KETTLE

RezumatIn literatura de specialitate exist o serie de relaiicriteriale cu care se dimensioneaz spaiul de vapori

din cazanul de abur tip Kettle. In lucrarea de faacesterelaii sunt analizate i comentate. Compararea lor s-arealizat pe baza unui exemplu numeric.

Scientific reviewers: Prof. Dr. Ing. Habil Ioana IONELProf. Dr. Ing. Mihai NAGI
https://www.researchgate.net/publication/255082645_Simplifying_reboiler_entrainment_calculations?el=1_x_8&enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ==https://www.researchgate.net/publication/255082645_Simplifying_reboiler_entrainment_calculations?el=1_x_8&enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ==https://www.researchgate.net/publication/255082645_Simplifying_reboiler_entrainment_calculations?el=1_x_8&enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ==https://www.researchgate.net/publication/255082645_Simplifying_reboiler_entrainment_calculations?el=1_x_8&enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ==https://www.researchgate.net/publication/255082645_Simplifying_reboiler_entrainment_calculations?el=1_x_8&enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ==https://www.researchgate.net/publication/255082645_Simplifying_reboiler_entrainment_calculations?el=1_x_8&enrichId=rgreq-4b941b82-c2b4-47e8-8c26-b2228d8ee70d&enrichSource=Y292ZXJQYWdlOzI3NDY0ODQyNztBUzoyMTU4OTcyOTQ4MDcwNDFAMTQyODQ4NTMzNDkzMQ==

Documents

2008 02 Bulletin Timisoara