ANTIFOAMING AGENTS PERFORMANCE EVALUATION *

Monazir Imam, Ata Yaseen Abdulgader, Ghulam M. Mustafa, Radwan Al-Rasheed and Ibraheem Al-Tissan

Research and Development Center, P.O Box 8328, Al-Jubail, Kingdom of Saudi Arabia

Abdul Salam Al-Mobayed and Anwar Ehsan

Al-Jubail Desalination & Power Plant, Al-Jubail, Saudi Arabia.

ABSTRACT

Distillate contamination by salt carry over due to excessive foaming in multistage flash (MSF) distillers and detrimental foaming in deaerator section have been reported in Saline Water Conversion Corporation (SWCC) and other desalination plants. Application of suitable antifoaming agents not only maintains high quality of distillate but also improves release of dissolved oxygen in the deaerator section, thus improving the operating efficiency of MSF plants. Brose Chemical Company (BCC) and Albright and Wilson Limited (A&W) developers of antifoaming agents BCC-74M and Albrivap AF-2 respectively collaborated with SWCC in conducting trial runs to show that their products are as effective and economical as the one currently being used in SWCC plants.

Foam control, non interference with the antiscalant performance, distillate purity, and stability over a wide range of temperatures at low dosage levels were some of the important criteria taken while evaluating the performance of these antifoaming agents. Compatibility of these agents were determined initially in the laboratory followed by field trial runs in MSF pilot plant and commercial plants of Al-Jubail phases I&II in order to check the above criteria. During MSF plant runs distillate conductivity and make-up feed dissolved oxygen(DO) levels were maintained in the ranges of 1-27 S/cm and 5-47 ppb respectively. The higher DO was in Al-Jubail Phase I where deaeration takes place in the last stage of the distiller. These results were achieved at antifoam dose rates of 0.15 to 0.035 ppm. Once again higher dose rates at Al-Jubail Phase I were needed for the same reason mentioned above. Based on these results, one could say that data observed during these test runs showed satisfactory performance and thus conclude that these agents are comparable with the currently used antifoaming agents and can be effectively used in MSF plants of SWCC. *Presented in Second Acquired Experience Symposium, September, 1997, Al-Jubail *This paper is based on Technical Reports No. TR 96002 and TR 96005.

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INTRODUCTION Seawater is not a pure liquid. In addition to 3-4 % inorganic salts, it contains traces of

organic compounds that have surface-active properties. As a surface phenomenon, minute

quantities of organic compounds and fine particulate matter can promote foaming. Some of

the few basic principles related to foaming in MSF desalination plants are highlighted [1]

below:

1. Pure liquid do not foam. Presences of surfactant impurities are necessary for foaming to

occur and stabilize.

2. Foams are unstable and tend to collapse quickly to separate gas and liquid components.

Concentration of surfactant impurities opposes this collapse by several mechanisms.

3. The foam stability depends on many factors. Some of which are film viscosity, surface

elasticity, electrical repulsion and gaseous diffusion. Disruption of these conditions

enables to control foaming.

Antifoaming agents are usually non-ionic surfactants with temperature dependent solubility.

They have the important characteristics of low volatility, ease of dispersion, strong spreading

power and surface attraction and orientation. They act to lower the surface tension of the

vapor/liquid interface, reducing liquid film strength and surface viscosity and speeding

drainage from bubbles. Summaries of foam control agents used in various applications other

than desalination have been reported [2-3].

The effectiveness of antifoaming agents among more than 60 candidates from seven different

chemical classes was determined [1]. The effectiveness of the best one of these was further

verified in a 90 day trial run at a TBT of 108 oC on 2.2 MGD MSF recycle plant in Cura-

Cao(Werkspour) of the Dutch Antilles. In this test foaming was suppressed without affecting

the scale control agent at a dose rate of 0.03-0.05 ppm[1]. The effect of this antifoam on

brine heater and flash chamber scaling using single stage flash evaporator (as a simulation

module) at 120oC outlet temperature with normal recycle configuration was also studied[4].

Detrimental effect of foaming is not only found in MSF distillers but also reported in

deaerator section [5-8]. It has been reported that during the commissioning period of Jeddah

phase III, the deaerator was not performing according to design [5]. A detailed investigation

of this problem resulted in the replacement of existing liquid distribution device with a more

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controlled and suitable system. The initial application of this device on site immediately

showed an improvement in oxygen level from 200 down to about 80 ppb. However, this was

still significantly above the guaranteed figure and after a study of the particular antifoam is

being used, it became evident that the antifoam being used at the site was not suitable for the

full-scale plant deaerator. The antifoam normally used was adequate and sufficient for

controlling foam within the distillers, but did not perform satisfactorily at temperature levels

of the deaerator. Utilization of alternate antifoam, capable of operating at temperatures of

30oC and below, immediately improved the deaerator performance. This agent brought down

oxygen levels to less than 20 ppb as was desired.

Thus one can say that antifoaming agents should also serve the purpose of preventing

foaming either in the first few stages or in the deaerator, therefore, improving release of

dissolved oxygen in the deaerator hence preventing carry over of salts to ejector system[6]. In

other words foaming is a major reason for maloperation of deaerator columns [7]. The

effluent dissolved oxygen concentration is strongly dependent on the combined action due to

antifoam dosage rate and stripping steam [8]. Hence the importance of proper antifoam

dosage and stripping steam flow rate on the satisfactory performance of deaerator columns

must be emphasized. It has been further reported that deaeration of seawater can be effective

in lowering oxygen content down to the range of 80-200 ppb as demonstrated in a test using

single spray nozzle. However, for better deaeration i.e., to reduce oxygen level down to less

than 20 ppb, antifoaming agents are to be introduced upstream of deaerator nozzles. Efforts

to improve the performance and optimize the dosing rate of antifoaming agents are still

continuing. In this context certain new advances have been attained particularly by owners of

MSF plants in evaluating and optimizing the use of available antifoaming agents [9-10].

Antifoaming agents BCC-74M and Albivap AF-2 are claimed to be highly effective to

prevent foaming problems in MSF distillation plants. In addition to this, these antifoaming

agents are further characterized by some important and promising features such as their

efficiency over a wide range of temperature at low dosage levels, stable dispersion with

distillate at typical dosing solution concentrations, and economic viability. Table 1

specifically identify the important properties of these two antifoaming agents.The primary

objective of these trial runs is to evaluate the performance of BCC-74M and AF-2 in

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controlling foams without disturbing the effectiveness of scale control additives in MSF pilot

plant and commercial plants of Al-Jubail phases I&II.

DESCRIPTION OF TESTS Field trial runs on these antifoaming agents were conducted on an MSF Pilot Plant and

commercial plants of Al-Jubail Phases I&II. Table 2 summarizes the test conditions of these

antifoaming agents. Antifoam dose rate at pilot plant was 0.04 ppm, whereas the dose rate at

phase I was varied between 0.15-0.1 ppm. Dose rates for all ten units of Phase II (unit 11 to

20) were varied between 0.05-0.04 ppm. Dose rates of all the other units of phase II except

unit 12 were further reduced to the normal antifoam dose rate of 0.035 ppm. The antifoam

feed tanks concentrations were checked once per day (for each batch preparation) by

chemical analysis to be sure that the concentration was maintained. Solutions of 0.5 %

antifoam were separately injected into the make up seawater upstream of deaerators of pilot

plant and all units of phase II The solution concentration at Phase I was 1.0%. On-line ball

cleaning systems were operated as usual during all these tests to maintain high distiller

performance.

Miscibility behavior of these antifoaming agents in water was determined in the laboratory

prior to field trial runs. Sea water and brine chemistry, distillate conductivity, deaerator

performance, distillate contamination by organic carry over and potential for bacterial growth

and aftergrowth were closely monitored during performance evaluation of these antifoaming

agents. Performance test monitoring also required data logging of flow, temperature and

pressure measurements. The most important flow monitoring points were recirculating brine,

make-up seawater, distillate, brine heater condensate, and last yet quite important were the

monitoring of antiscalant and antifoaming agents dose rates. Brine heater terminal brine

recycle and vapor temperatures were also monitored. These data were used to calculate the

heat transfer coefficient of brine heater, plant performance ratio or gain output ratio.

RESULTS AND DISCUSSION Results of miscibility tests for the antifoaming agents BCC-74M and AF-2 reveal that at a

concentration of 0.5% and 1.0%, the antifoam solution remains homogeneous up to 24 hours

and then starts settling gradually. This observation was also confirmed during testing in Al-

Jubail commercial MSF units, where settling of antifoam in the preparation tanks as well as

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clogging in the antifoam dosing system were not noticed. Hence, it can be said that the

antifoaming agents BCC-74M and AF-2 are fully dispersible in water at the solution

concentration of 1.0% and 0.5% as normally practiced in phase I and C2/C3 units of Al-

Jubail Phase II plants. On the other hand, settling started much earlier for higher

concentration of 1.5% i.e., as the residence time increases; turbidity of antifoam solution was

noticed to decrease significantly. Thus it is essential that for such high concentration

extensive miscibility tests have to be conducted taking into consideration actual plant

operating conditions.

As earlier stated, excessive foaming in the MSF distiller results in the contamination of

distillate by salt carry over. Antifoaming agents are added to the make-up feed to maintain

distillate quality by preventing foaming and hence salt carry over. Graph (a) of Figures 1

through 4 show the variation in distillate conductivity versus time. The maximum values of

distillate conductivity in the pilot plant and commercial units of Al-Jubail Phase II were

recorded to be 27 and 4S/cm respectively for antifoaming agents BCC-74M and AF-2

except in unit 13 for AF-2, where the conductivity was found varying in the range of 8-20

S/cm. These values are well within the design acceptable limits and satisfying the

specification of these plants. Higher distillate conductivity in unit 13 was due to the fouled

condition of demister pads prior to the trial run of AF-2, while in Pilot plant is mainly due to

the violent flashing in limited number of distiller stages. Moreover, the lower demister height

and the limited overall volume of MSF pilot unit contribute to the higher conductivity of the

distillate.

Detrimental foaming in the deaerator section has been reported in many MSF desalination

plants. Selection of proper antifoam improves deaerator performance [5-8]. Hence,

monitoring of dissolved oxygen in the make up feed downstream of deaerator was essential

to assess the ability of the antifoaming agents in preventing foaming in deaerator section and

subsequently maintaining acceptable oxygen levels. Variation in dissolved oxygen in make

up stream after deaeration is shown in graph (b) of Figures 1 through 4. The maximum level

of dissolved oxygen in make-up stream of Al-Jubail pilot plant as well as phase II units

varied in the range of 9-15 ppb for both antifoaming agents. These values were within the

acceptable limits of less than 20 ppb after deaeration, which implied the integrity of these

antifoaming agents within the operating temperature range of phase II deaerators. On the

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other hand the dissolved oxygen content in the recycle brine in phase I varied in the range of

45-47 ppb. These values are considerably higher compared to pilot and phase II units because

(as earlier pointed out) at phase I deaeration takes place within the last stage of the distiller in

the absence of external deaerator.

Maintenance of effective scale control is the most crucial factor in MSF desalination process.

Some of the effective antifoams may reduce antiscalant activity resulting in 40-50% more

scale[1]. Therefore, the compatibility of these antifoaming agents with antiscalant under use

was checked by calculating plant performance ratio (PR) or gain output ratio (GOR) along

with the overall heat transfer coefficient (HTC). Variation in brine heater heat transfer

coefficients in pilot and Al- Jubail Phase I plants are shown in graph (c) of Figures 1 and 2.

These values of heat transfer coefficients in both plants remained stable throughout the test

runs for both antifoaming agents and did not show any kind of deterioration in their

performance at top brine temperatures (TBT) of 112 and 90 0C in the same order as above.

Brine heater heat transfer coefficients of unit 12 were also found stable at a TBT of 104 0C as

shown in graph (c) of Figure 3. Heat transfer coefficients of brine heater in unit 13 showed

some variation in the case of BCC-74M only as shown in graph (c) of Figure 4, which can be

attributed to load change. The calculated performance parameters in terms of Gain Output

Ratio (GOR) in pilot plant and Al-Jubail phases II&I are shown in graph (d) of Figures 1

through 4. During the trial runs, there was no marked decline in the performance of any

distiller under test. These results basically indicate that no significant scale precipitation took

place in brine heaters or in the heat recovery section during trial runs using these antifoaming

agents. Some specific conditions and results obtained during these tests are also shown in

Tables 3 and 4, which also confirm the effectiveness of these two antifoaming agents

It is also possible that the antifoaming agents may contaminate the distillate by its

constituents. Frequent analysis of distillate was therefore necessary to ascertain the

presence/absence of any organic pollutants carried over into the distillate. Organic carryover

was monitored by Gas Chromatography-Mass Spectrometer (GC/MS) technique using

USEPA 625 method. Figure 5 represents chromatogram of the distillate samples obtained by

GC/MS. It can be seen from the figure that neither the antifoam as whole nor any toxic

components derived from antifoaming agents were carried over into the distillate. Hence it

1387

can be stated that the distillate purity was unaffected during the trial runs of these

antifoaming agents.

Increased bacterial after growth and consequently higher fouling potential could be due to

supply of nutrients by the antifoaming agent. Bacterial growth and after growth were thus

determined in samples of: (i) raw seawater (ii) make-up feed (iii) antifoam mixing tank, and

(iv) product water which is used as diluent in mixing tank. Results of bacterial counts for

bacterial growth and after growth potentials are presented in Tables 5 and 6. These showed

that bacterial after growth obtained from samples containing antifoam were either lower or

similar to raw sea water samples. It is therefore concluded that the antifoam is not enhancing

nor contributing to the bacterial growth and would not be anticipated to result in fouling of

antifoam dosing system.

CONCLUSIONS

1. Antifoaming agents BCC-74M and AF-2 solutions were fully dispersible in water at a

concentration of 0.5 and 1.0%, as no settling of antifoam in preparation tanks nor

clogging in the dosing system was noticed.

2. Bacteriological analysis of make-up water and antifoaming agents showed that, they are

not a source of contamination. Furthermore after growth potentials for bacteria indicated

that the antifoaming agents were not enhancing growth and consequently biofouling.

3. Dissolved oxygen levels in the make-up feed after deaerations were within acceptable

limits of less than 20 ppb. The only exception of Al-Jubail Phase I unit which varied

between 45-47 in the recycle stream.

4. Distillate quality was maintained within the acceptable range of 1-27 S/cm. On the

other hand carry-over of any steam-volatile component related to the antifoam was also

not detected, thus maintaining the distillate purity over the entire duration of these test

runs.

5. At dose rates of 0.15 down to 0.035 ppm these antifoaming agents were effective at all

MSF operating temperatures (TBT 90-1120C) and found compatible with the antiscalant

presently under use. Moreover, the overall performances of monitored distillers were

found satisfactory during these trial periods, (see attached Tables 3 and 4 also Figures 1

to 4). Hence, it can be concluded that the subject antifoaming agents are acceptable for

MSF application. 1388

RECOMMENDATIONS

1. The results of these evaluation tests indicate that the performance of BCC-74M and AF-

2 are quite satisfactory and can be used in MSF plants as effective antifoam agents.

2. The observed performance of antifoaming agents BCC-74M and AF-2 in pilot and

commercial plants of Al-Jubail phase II at dose rates of 0.04 and 0.035 ppm and TBT of

112 and 92 0C respectively was satisfactory. It is therefore recommended that further

dose rate optimization is to be carried out.

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REFERENCES 1. Auerbach, M. H., O.Neill J. J., Reimer R. A. and Walinsky S. W. (1981) Foam Control

Additives in MSF Desalination, Desalination, 38, 159-167. 2. Owen, M. J.(1985) Antifoaming Agents, In Encyl. of polymer Science and Engineering,

2nd edn; (Edited by Mark, H. F., Bikales N. M., Overberger C. G. and Menges G.) A Wiley Interscience, USA, 164-171.

3. Lichtman, J. and Gammon T. (1979) Defoamers, in Encycl. of Chemical Technology, 3rd

edn; Edited by Kirk-Othmer) A wiley Interscience, USA, 430-448. 4. Auerbach, M. H. and Carruthers M. S. (1979) Laboratory Application Testing of

Desalination Antiscalants, Desalination, 31, 279-288. 5. Abkar, A. A., Girgis F. and Von Loebbecke H. D. (1986) Operating Experience Related to

SWCC Desalination plant Jeddah III in the Kingdom of Saudi Arabia, Topics in Desalination, SWCC, Saudi Arabia, 104-105.

6. Nada, N., Khumayyis D. and Al Hussain M. (1985) Economical Evaluation of Al-Khobar

Phase II 50 MIGPD at Three Different Mode of Operation, Desalination, 55, 43-54. 7. Eckert, J. S. (1970) Selecting the Proper Distillation Column Packing, Chemical

Engineering Progress, 66(3), 39-44. 8. Rabas, T. J., Inoue S. and Shimizu A. (1987) An Update on the Mass Transfer of

Counterflow, Packed Deaerators Containing Pall ring Packing, Desalination, 66, 91-107. 9. Imam, M., Abdulgader A. Y., Mustafa G. M., Al-Rasheed R., Al-Tissan I., Al-Mobayed

A. S., Ehsan, A. and Dayley D. (1996) Performance Evaluation of Antifoam Additive BCC-74M on MSF Pilot plant and Commercial Plants of Al-Jubail Phase I&II, R&D Center, SWCC, Al-Jubail, Technical Report No. TR96002.

10.Pujadas, F., Fukomoto Y. and Isobe K. (1991) Performance Test of Antiscalant

Aquakreen KC-550 under a wide range of temperature conditions at the MSF Desalination Plant in Abu Dhabi, Desalination, 83, 65-75.

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Table 1. Technical specifications of BCC-74M and AF-2

S.No. Properties AF-2 BCC-74M 1 Specific gravity (20 0C) 1.02 1.02 2 pH(1%aqueous

dispersion) 7 7

3 Solubility in water Dispersible Dispersible 4 Appearance Pale amber

liquid Pale yellow liquid

5 Odor Faint Oily

Table 2. Test Conditions

S.No.

Parameters AF-2 BCC-74M

PP Ph II PP Ph I Ph II 1 Test duration

(days) 7 30 7 7 21

2 No. of units (distiller no.)

1 10 (11-20) 1 1(5) 10 (11-20)

3 TBT ( 0C) 112 105/92 112 88 105/92 4 Concentration

ratio 1.38-1.4 1.34-1.41 1.38-1.4 1.39-

1.41 1.34-1.41

5 Antiscalant used DSB(M) BEV2000 DSB(M) DSB(M) DSB(M) 7 Antiscalant dose

rate (ppm) 2.0 1.5/1.0 2.0 1.0 1.5/1.0

8 Antifoam dose rate (ppm)

0.04 .05/.04/.035 0.04 0.15/0.1 .05/.04/.035

9 Antifoam tank conc.

0.5% 0.5% 0.5% 1.0% 0.5%

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Table 3. Typical Plant Performance Data

Parameters Unit AF2 BCC-74M PP U12,

PhII U13, PhII

PP U5, PhI

U12, PhII

U13, PhII

Condensate m3/hr 0.35 125 125.8 0.35 128 132 117-136 Flow Brine recycle 6.53 9200 10000 6.53 10800 9210 10300-

10500 Rate Production 1.15 1060 945 1.15 970 1121 900-1050

Make up 2.15 3025 2500 2.15 2750 3175 2100-2650

Blow down - 2100 1725 - 1750 2190 1700-2150

Inlet to Brine Heater oC 90 96.3 88.2 90 80.6 96 84-88 Outlet of Brine Heater 112 103.1 94.8 112 88 104 92-95

Temp. Condensate 117 108.8 100.3 117 92 109 95-100 Recovery tube inlet 35 34.5 36 35 34 35 34 Make up 34 34 36 34 34 35 34

Seawater 18 28 28 18 24 27 27 Brine Heater HTC W/m2 C 4030 2662 2800 2850 3715 2914 2500-

4200 GOR (kg distillate/ kg

steam 2.8 8.77 7.77 2.4 7.84 8.76 7.6-8.17

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Table 4. Typical Chemical Analysis Data

Parameters Unit AF-2

BCC-74M

PP U12, PhII

U13, PhII

PP U5, PhI

U12, PhII

U13, PhII

Chlorides ppm 22727 23550 23500 22350 23700 23660 23660 Sea water Conductivity S/cm 59600 60200 60200 59350 61200 60786 60783

M-alkalinity as CaCO3 ppm 129 131 131 130 131 131 131 pH - 8.36 8.24 8.24 8.23 8.35 8.27 8.27 Residual chlorine ppm - 0.3 0.3 - 0.25 0.25 0.25

Make-up Dissolved oxygen ppb 6-9 10-17 10-17 5-9 - 12 12 Chlorides ppm 31148 31553 32834 31273 33200 31684 33019

Recycle Brine

Conductivity S/cm 73800 76400 79500 76837 80450 76717 79950

pH - 8.68 8.64 8.61 8.61 8.71 8.72 8.65 Conc. ratio - 1.38 1.34 1.4 1.39 1.4 1.34 1.39

Dissolved oxygen ppb - - - - 45-47 - - Blow down Chlorides ppm 34953 35375 36250 34820 36268 36096 36383 Conductivity S/cm 80100 83600 85700 84890 86040 85200 86000 pH - 8.8 8.85 8.75 8.71 8.78 8.85 8.75 Distillate Conductivity S/cm 23.1 1.89 9.97 25-27 1.55 2.57 1.53 pH - 6.62 6.82 6.76 6.67 6.75 6.75 6.73

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Table 5. Mean counts of bacterial growth and after growth Potential (N=9) of various samples on day 2

Sample Bacterial Count (cfu/ml) AF-2 BCC-74M

Zero hour 24 hours 72 hours Zero hour 24 hours 72 hours

Raw Seawater 4.2 x 103 8.1 x 104 1.9 x 105 4.2 x 103 8.1 x 104 1.9 x105

Mixing tank 3.9 x 102 3.2 x 105 5.1 x 105 - 3.9910 5 1.82 x 105

Make-up feed 4.9 x 103 3.9 x 105 3.9 x 105 - 4.7 x 105 1.82 x 105

Product water 3.0 0 0 3.0 0 0

Table 6. Mean counts of bacterial growth and after growth

Potential (N=9) of various samples on day 7

Sample Bacterial Count (cfu/ml)

AF-2 BCC-74M

Zero hour 24 hours 72 hours Zero hour 24 hours 72 hours

Raw Seawater 3.7 x 103 7.9 x 104 1.8 x 105 1.67 x 102 - 3.17 x 106

Mixing tank 2.9 x 103 1.3 x 104 1.0 x 105 5.73 x 104 - 2.8 x 103

Make-up feed 2.9 x 103 1.0 x 105 2.2 x 105 2.93 x 103 - 4.07 x 105

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Figure 1. Performance of Antifoaming Agents in RDC Pilot Plant at Al-Jubail

20

22

24

26

28

30

0 50 100 150 200

Co

nd

uct

ivit

y, u

S/c

m

BCC(Cond) AF2(Cond)

0

5

10

15

20

0 50 100 150 200Dis

solv

ed O

xyg

en, p

pb

BCC(DO) AF2(DO)

1

2

3

4

0 50 100 150 200

Time, Hours

Gai

n O

utp

ut

Rat

io

BCC(GOR) AF2(GOR)

0

1

2

3

4

5

0 50 100 150 200

Hea

t T

ran

sfer

C

oef

f., k

W/m

2 K BCC(HTC) AF-2(HTC)

Graph (a)

Graph (b)

Graph (c)

Graph (d)

1395

0

1

2

3

4

0 50 100 150 200

Co

nd

uct

ivit

y, u

S/c

m

BCC(Cond)

7

8

9

10

0 50 100 150 200

Time, Hours

Gai

n O

utp

ut

Rat

io BCC(GOR)

3

4

5

0 50 100 150 200

Hea

t T

ran

sfer

C

oef

f., k

W/m

2 K

BCC(HTC)

40

45

50

0 50 100 150 200Dis

solv

ed O

xyg

en, p

pb BCC(DO)

Figure 2. Performance of Antifoaming Agent BCC-74M in Al-Jubail Phase I Unit 5

Graph (a)

Graph (b)

Graph (c)

Graph (d)

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Figure 3. Performance of Antifoaming Agents in Al-Jubail Plant Phase II Unit 12

0

1

2

3

4

5

0 100 200 300 400 500 600 700

Co

nd

uct

ivit

y, u

S/c

m

BCC(cond) AF2(cond)

0

5

10

15

20

0 100 200 300 400 500 600 700Dis

solv

ed O

xyg

en, p

pb

BCC(DO) AF2(DO)

7

8

9

10

0 100 200 300 400 500 600 700

Time, Hours

Gai

n O

utp

ut

Rat

io

BCC(GOR) AF2(GOR)

0

1

2

3

4

5

0 100 200 300 400 500 600 700

Hea

t T

ran

sfer

C

oef

f., k

W/m

2 K BCC(HTC) AF2(HTC)

Graph (a)

Graph (b)

Graph (c)

Graph (d)

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Figure 4. Performance of Antifoaming Agents in Al-Jubail Plant Phase II Unit 13

0

5

10

15

20

0 100 200 300 400 500 600 700

Co

nd

uct

ivit

y, u

S/c

m

BCC(Cond) AF2(Cond)

0

5

10

15

20

0 100 200 300 400 500 600 700Dis

solv

ed O

xyg

en, p

pb

BCC(DO) AF2(DO)

7

8

9

10

0 100 200 300 400 500 600 700

Time, Hours

Gai

n O

utp

ut

Rat

io

BCC(GOR) AF2(GOR)

0

1

2

3

4

5

0 100 200 300 400 500 600 700

Hea

t T

ran

sfer

Co

eff.

, kW

/mK

BCC(HTC) AF2(HTC)

Graph (a)

Graph (b)

Graph (c)

Graph (d)

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Figure 5. Chromatograms of distillate samples

BCC-74M

AF-2

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