Poster PO-36

PO-36.1

DIRECT SEAWATER COOLING IN LNG LIQUEFACTION PLANTS

Craig Thomas VP, Marketing & Applications Engineering

High Performance Tube, Inc.

Robert Burlingame Technical Advisor - Mechanical

Kellogg Brown & Root

ABSTRACT

Seawater is one of the most abundant, efficient, and inexpensive cooling mediums available. Consequently it has been employed in over 50% of the grassroots LNG plants built since the 1960’s. All of the seawater cooled plants operating today utilize a once-through delivery method for direct or indirect contact with the process heat exchangers. For the large heat duties, which include the refrigerant condenser and compressor coolers, the most common and efficient approach is direct seawater cooling.

The macro engineering considerations for selecting the right cooling method are reviewed including once-through seawater, seawater cooling tower, and air cooling. The use of a seawater cooling tower is new for LNG Liquefaction plants, but offers an opportunity to reduce the cost and environmental impact associated with once-through seawater.

Reliability and maintainability of heat exchangers is perhaps the most critical factor in

the consideration of seawater cooling. A historical survey of existing LNG plant experience with direct seawater cooling is presented and provides valuable insights for owners, operators, and engineers considering new plants and expansions. Material selection, corrosion and erosion rates, fouling, cleaning and water treatment are considered and comparisons drawn from reported plant owner experience.

Proper design of direct seawater cooled, shell and tube heat exchangers is an

important factor in reducing capital costs and maintenance costs, while boosting efficiency. The use of titanium low finned tubing and anti-vibration support structures is considered for refrigerant condensing and compressor cooler services. These newer technologies are applicable for grassroots plants in design phase, and also effective for retrofitting existing plants.

Practical considerations must be made with regard to the availability of materials

required for seawater heat exchangers. Titanium and nickel alloys are in high global demand at present, and an understanding of market supply and demand conditions is essential for the LNG plant developer. A practical overview of the titanium market is presented, including procurement strategies for long lead time materials.

Poster PO-36

PO-36.2

Introduction

Seawater cooling has been an accepted standard in LNG service since the 1960’s and continues to be a cost effective and efficient means of heat rejection. There are 24 LNG plants in operation today comprising 77 individual liquefaction trains that utilize once-through seawater cooling. In 48 out of these 54 trains, a direct method of seawater cooling (see figure 1) is used for the main shell and tube heat exchangers, including the refrigerant condenser, sub-cooler and compressor coolers. For the smaller heat exchangers, it is common to employ an indirect, or closed loop system whereby the seawater is used to cool fresh water through the use of plate and frame exchangers. Some LNG plants choose indirect seawater cooling for all the heat transfer services, including the refrigerant condenser and coolers, and avoid direct seawater completely ( see figure 2). Alternatively, fan driven air coolers can be used in place of seawater for some or all of the heat exchangers. Currently there are 18 liquefaction trains in service utilizing air cooling, with several more under construction. Table 1 below summarizes the cooling methods and LNG plants in existence today.

Table 1: Cooling Methods Used in LNG Plants

Method Plants Trains Locations Once-though Direct Seawater

11 48 Indonesia: Bontang, Arun Algeria: Arzew, Skikda, Bethioa Malaysia: Bintulu UAE: Das Island. Qatar: RasLaffan (Qatargas ) Oman Norway Yemen ( under construction)

Once-through Indirect Seawater

2 6 Qatar: Rasgas , Rasgas II, Qatargas II

Cooling Tower (Fresh Water)

1 3 Nigeria

Air Coolers 10 20 Australia: NW shelf, Darwin Egypt: Diametta, SEGAS Malaysia (MLNG Tiga) Nigeria (2 trains) E. Guinea (under construction) Trinidad Alaska Russia ( under construction)

The schematic diagrams shown in figures 1 through 4 compare the process design for once-through seawater cooling (direct and indirect) and a re-circulating seawater cooling tower (direct and indirect) for a typical LNG plant. The comparison focuses on the refrigerant condenser, sub-cooler, and compressor coolers which typically comprise 80% of the heat rejection duty. It is assumed that an indirect, fresh water cooling loop for the smaller heat exchangers is utilized in each case.

Poster PO-36

PO-36.3

Comparison of Cooling Methods The decision for cooling method is a complex one involving local environmental and

regulatory issues in addition to capital cost, operating cost, availability, maintenance, reliability, energy efficiency, and stability of operation. It is beyond the scope of this paper to analyze in detail the benefits and features of each method, however, there are

Poster PO-36

PO-36.4

certain generally accepted engineering trade-offs to consider, which are summarized in table 2 below. The comparison is limited to the propane condenser and compressor coolers for simplicity. Five options are considered, including once-through seawater (direct and indirect), seawater cooling tower (direct and indirect), and air cooling. The make up water source for the cooling tower could be seawater, natural fresh water, desalinated seawater, or treated waste water. For comparison purpose, we have assumed seawater.

Table 2: Comparison of Cooling Method for LNG Plant (Propane Refrigerant Condensers and Compressor Coolers) Once-through Seawater

Seawater Cooling Tower Comparison

Direct (Figure 1)

Indirect (Figure 2)

Direct (Figure 3)

Indirect (Figure 4)

Air Coolers

Reliability Good Assuming proper material selection

Good But more equipment to maintain than direct SW

Good Assuming proper material selection

Good. But more equipment to maintain than direct SW.

Good. Depending on environmental conditions

Maintenance Periodic cleaning at turnarounds. Continuous, self-cleaning systems also available.

May be cleaned during normal operation.

Periodic cleaning at turnarounds. Continuous, self-cleaning systems also available.

May be cleaned during normal operation.

No cleaning required. Motors can be replaced during normal operation.

Electric Power consumption

Site specific (Typically lowest)

Site specific (Typically lowest)

Site specific (Typically medium)

Site specific (Typically medium)

Site specific (Typically highest)

Stability of Production

Stable

Stable Stable Slow changes effected by dew point

Stable. Slow changes effected by dew point

Less stable. Cycles daily, and affected by weather conditions

Safety Factor Safe (Leaks into sea water are contained and may be vented to a safe location)

Safe (Leaks into fresh water are contained and may be vented to a safe location)

Safe (Leaks into sea water are contained and may be vented to a safe location)

Safe (Leaks into fresh water are contained and may be vented to a safe location)

Moderately Safe (Leaks are difficult to detect. In addition they are uncontrolled and cannot be contained. However, Leaks are usually not explosive due to a dilution effect with air.

Poster PO-36

PO-36.5

Capital Cost Site specific.

Typically lowest

Site specific. Typically higher

Site specific Typically lowest

Site specific. Typically higher

Site specific. Typically highest

Environmental Impact

Challenging due to high volume of chlorinated, once through seawater

Challenging due to high volume of chlorinated, once through seawater

Manageable due to lower volume of once through seawater

Manageable due to lower volume of once through seawater

Lowest but high noise level.

Advantages of Direct Seawater Cooling

Assuming seawater is available and the local environmental and regulatory standards can be met, the use of direct seawater for cooling requires the least external electrical power generation, and is the most cost effective, safe, and process stable. Unlike Air coolers, which must operate over wide fluctuations in temperature, seawater coolers have a predictable, narrow and more stable temperature range. Furthermore, direct seawater (Fig 1&3), as compared to indirect seawater ( Fig 2 & 4), offers the highest efficiency and compactness, through wider temperature approach and fewer heat exchangers and pumps required. Direct seawater is most beneficial in the larger heat duties such as the refrigerant condenser and compressor coolers. In these services, four extra degrees of temperature approach can make a significant difference in terms of the overall efficiency and sizing of heat exchangers. For the smaller exchangers, the temperature approach and efficiency are less important, and therefore, the addition of a closed, fresh water loop can be justified from a maintenance and cost standpoint. Plot Space & Layout

The plot space required is site specific, but it will be approximately the same for sea water and air cooled plants, if the air coolers can be placed overhead the pipe rack. Air coolers require large headers, and therefore the cost of process piping will be more than for seawater coolers, which are simpler in layout. Safety

Direct seawater cooling with shell and tube exchangers is also considered safer than air coolers. Hydrocarbon leaks are less hazardous since they are confined in a closed pressure vessel and piping system, instead of being vented to open air environment overhead of the plant and personnel. There is also a significantly lower noise level with a seawater system compared to air coolers, and the noise can be localized to pumps and cooling tower and is not spread over top of the entire plant. Scalability

One advantage of air cooled systems is they are modular and can be added incrementally without a large pre-investment. A once through seawater delivery system involves considerable pre-investment costs if future expansions are planned. However, the use of seawater cooling towers as part of future expansion could reduce the pre-investment costs significantly. Cost Comparison

It is difficult to make a generalized cost comparison between cooling methods because each plant site has unique geographic and environmental conditions, however, if

Poster PO-36

PO-36.6

seawater is available, and in close proximity to the plant, then it is typically the most cost effective method of heat rejection. Assuming that seawater is chosen as the cooling medium, there remains a choice between direct or indirect seawater cooling. The table below offers a recent cost study comparing the cost of direct and indirect seawater cooling for the largest exchanger, the propane refrigerant condenser. The direct seawater cooling method is approximately half the cost. Some LNG facilities have switched to indirect seawater cooling for all heat exchangers based on a concern that direct seawater will have higher long term maintenance costs. This argument had merit in the past due to problems with copper alloy tubes, however it should not be a concern today if titanium is utilized.

Table 3: Direct Vs. Indirect Seawater Cooling Cost Comparison Propane Refrigerant Condenser ( based on recent estimates)

Equipment Direct Seawater Cooling Indirect Seawater Cooling Propane Condenser $12,000,000 (1) $4,600,000 (2) Installation ( erection, piping, and foundation work)

$4,600,000 (6)

$4,600,000 (6)

Sea Water / Fresh Water Plate & Frame Interchanger

Not required $9,900,000 (3)

Installation of Plate & Frame Interchanger

Not required $4,400,000

Extra Fresh Water pumps Not required $1,100,000 (4)

Installation of pumps Not Required $1,100,000 Extra Power for pumps Not required $5,300,000 (5)

Larger Fresh Water Drum $600,000 Total Cost $16,600,000 $30,500,000

(1) Titanium Finned Tube Surface = 94,500 ft2/shell. 4 Shells at 88’’ diameter x 28’ long. Weight/shell = 124,000 lbs. (Based upon 2006 titanium price level). (2) Carbon steel finned tube surface = 100,000 ft2 / shell. 5 shells at 90’’ diameter x 24 ft long Weight/shell = 190,000 lb (Based on recent Vendor proposals - +/- 25%) (3) 9 Titanium Plate and Frames with surface/frame = 24,300 ft2. Shipping weight/frame = 48,000 lb. Cost is based on $35/lb for titanium plate. Delivery is 2.5 years. Data is from a Vendor quotation. (4) 3 Pumps at 38,000 GPM/pump, 1750 hp/pump (Based on estimate by KBR machinery engineer +/- 25%) (5) Evaluated cost of power for pump motor = 3 x $1000 x 1750 = $5,300,000 Evaluated at $1000 / hp (Includes cost of fuel for 6 years, extra generating equipment, power lines, etc) (6) For the carbon steel condensers the cost/shell for installation is assumed to be the same as the exchanger cost = $920,000. The titanium condenser has approximately the same dimensions, but 25% is added due to the higher cost of the pipe and valves. Installation cost includes the associated pipe, valves and strainers.

Overcoming Obstacles to Seawater Cooling

One of the major obstacles to seawater cooling today is increasing environmental regulations. Several LNG plants that already utilize once-through seawater systems are

Poster PO-36

PO-36.7

considering air coolers for future expansion due to limits in how much seawater can be discharged in a given area and at a given temperature. In such cases, a seawater cooling tower could be a viable solution for maintaining the benefits of seawater cooling without exceeding the temperature rise and chemical injection limits associated with a once-through seawater system. Seawater Cooling Tower

With a cooling tower, the volume of water transferred in and out of the sea is approximately 1/10 of that required in a direct once through system, depending on local climate conditions. The seawater intake and outfall is based on the evaporation rate for the Cooling tower and not the constant heat rejection duty of the heat exchangers. The need for chlorination is also reduced or eliminated due to the higher chloride concentration in a cooling tower which eliminates most biological growth, a major fouling agent. The tower discharge would be remixed with un-concentrated seawater before discharge to the sea, and the amount of chlorine, corrosion inhibitors, etc returned to the sea with the blowdown water is minimal compared to the once through sea water system.

The seawater delivery system is also significantly reduced in size and cost because

the volume of flow and the reliability required is significantly reduced. A Once-through seawater system requires a highly reliable (and expensive) intake in order to avoid emergency plant shutdowns. A seawater cooling tower system does not need a highly reliable sea water intake system, since it can operate for a significant time without fresh sea water. This will allow maintenance on the sea water intake during plant operation. In addition, the sea water intake can be combined with the fire water intake (which is always required for a plant), and may therefore not add much cost to the plant. In addition, if the proposed LNG plant is an expansion to an existing facility which uses once-through sea water, the sea water intake for the cooling tower could be taken directly from the discharge of the existing plant.

The SW cooling tower approach has been successfully used in large refineries and

petrochemical plants but not yet in an LNG plant. References support the basic reliability of seawater cooling towers. Heat Exchanger Reliability

Another major challenge for direct SW cooling is the reliability of shell and tube heat exchangers. There are many lessons that have been learned over the past 40 years which, if taken into account, can greatly improve the reliability of heat exchangers in aggressive and changing seawater conditions. Perhaps the single most important factor is material selection. Lessons Learned and Material Selection

The use of copper alloys, including AlBr, and CuNi were wide spread in the first LNG plant installations in Algeria, Indonesia, Maylasia, and the UAE. The experience differs according to seawater condition, with some services having tube failures due to corrosion and erosion within a few years of installation and some maintaining acceptable

Poster PO-36

PO-36.8

service for over 10 years. However, in most cases, copper alloy tubes have failed when there is an unpredicted change in seawater condition, or in the plant operating condition. For example, in one plant, copper alloy heat exchanger tubes failed due to stagnant seawater left in the exchanger during shutdown. MLNG Dua

In the MLNG Dua LNG facility in Malaysia, aluminum brass heat exchanger tubes have failed due to two major factors. The primary cause was traced to air ingress in piping leading to erosion of the soft AlBr material, particularity after transition areas where tube diameter changed. The second factor was low pump pressures which reduced seawater velocities and created fouling which then led to under deposit corrosion of the tubing. Corrections were made in piping and pumps, and the heat exchangers tubing was replaced in kind with aluminum brass. Bontang LNG

At the P.T. Badak, Bontang LNG facility trains A -D, copper alloy tube failures occurred due to seawater corrosion, causing unexpected shutdowns. Investigaton revealed the primary cause was corrosion under calcium carbonate scale / deposits that formed at high tube wall temperatures, or hot spots. Sulfide attack is also believed to be a strong contributing factor. Several attempts were made to solve this problem, including installations of online sponge ball cleaning systems. The copper nickel tube specification was also modified to increase Iron content. Additionally, special shop alumina blasting was applied for interior tube cleaning. The results of these efforts were not satisfactory. Pt. Badak finally decided to replace the exchangers with titanium tubes, and after 8 years of service, reported significant improvement in equipment reliability. Titanium

The more recent LNG plants, such as QATARGAS trains 1,2 3, and Bontang trains E,F,G (and including retrofits of trains A-D referenced above), have followed the lessons learned from previous LNG and power plant services and employed titanium tubing in place of copper alloys in direct seawater cooling services. For the refrigerant loop heat exchangers, including the propane condenser, sub-cooler, and compressor coolers, the titanium tubes typically have an integral low finned surface on the OD which greatly improves heat transfer efficiency. Titanium tubing has proven immune to seawater corrosion or erosion under a wide range of conditions, and therefore can be specified in a much thinner wall than copper alloys. The industry standard for smooth titanium tubes in most LNG plants is .89 mm or .035 inches. In the case of low-finned tubes the accepted standard is now .71 mm or .028 inches in the root section under the fins. In contrast, CuNi tubes should have a minimum thickness of 1.6 mm (0.065”) under the fins, and still requires very careful control of seawater quality and flow rates.

There is over 2 million feet of titanium low finned tubing in the propane condensers

and compressor coolers in the Qatargas LNG trains 1,2 and 3, that have now been in service for over 10 years without failure, or reported incident. In Bontang, Indonesia, titanium low fin tube exchangers have been in service as long as 15 years with no

Poster PO-36

PO-36.9

reported corrosion or erosion concerns. There has been one reported failure related to vibration caused by fabrication error.

Due to incompatible materials, it is not possible to re-tube an existing copper alloy exchanger with titanium tubes, however, new bundles with titanium tubes and titanium clad tube sheets can be inserted into existing shells, or new heat exchangers retrofitted into existing piping and foundations. If the original bundles have smooth copper alloy tubes, then a retrofit with low-fin titanium tube bundles can improve both reliability and heat transfer performance. Each case is unique and depends on available pressure drops and seawater flow rates. Material Selection and Life Cycle Cost

Maintaining reliable service for a stable return on investment over a 20 to 30 year LNG sales contract is of critical importance to the LNG plant owner. Copper alloy heat exchangers are typically 25-50% less expensive than titanium in terms of capital cost, however, they can be significantly more expensive in terms of life cycle and maintenance costs. Considering the likely hood of changes in seawater quality (chemistry and amount of particulates), as well as the likelihood of upsets in plant operating conditions (changes in pump pressures and seawater velocities) during a 30 year LNG plant life cycle, the chance of serious maintenance problems related to copper alloys is quite high. As an example, if the cost of lost production due to unplanned down time is $400,000/day and the cost adder for titanium tubing is $4,000,000.00, then this added capital cost for titanium would be recouped within 10 days down-time. This does not include the added costs to repair or replace the failed heat exchangers. In this light, titanium could be viewed as an insurance policy on the overall plant investment by minimizing the risk of lost LNG production or reduction of capacity.

Table 4 provides a brief reliability history of shell and tube exchangers in direct

seawater cooled LNG liquefaction trains. It is understood that performance of materials is site specific and dependent on local seawater quality and plant operating conditions.

Table 4: Heat Exchanger Tubing material Reliability History Direct Seawater Cooled LNG plants

LNG Plant

Tube Material

Span of Service

Reported Experience Maintenance Actions

1

Aluminum Brass (18 BWG)

3 Rapid corrosion / erosion Retubed, 70/30 CuNi (18 BWG)

2 70/30 CuNi (18 BWG)

20 Slow corrosion Shells replaced with 70/30 CuNi (20 BWG)

3 70/30 CuNi (20 BWG)

5 Rapid corrosion / erosion

Full length 317SS liner installed inside tubes

4 70-30 CuNi

10-15 Isolated corrosion & erosion. Some tube leaks

Original exchangers still in service Some tube plugging

Poster PO-36

PO-36.10

5 Titanium

5 No corrosion or erosion Some vibration issues, leaks Shell replaced

6 90/10 CuNi 8-10 Slow erosion

/corrosion Shells replaced with Titanium tubes

7 Titanium

10-15 No corrosion /erosion reported Original exchangers still in service

8 70/30 CuNi 10-15 No issues

reported Original exchangers still in service

9 Titanium 15 No issues

reported Original exchangers still in service

10 Titanium 8-10 No issues

reported Original exchangers still in service

11 Titanium 3-5 No issues

reported Original exchangers still in service Table 5 provides a summary of the lessons learned in the design of shell and tube exchangers in direct seawater cooled services. The lessons are primarily related to material selection, operating conditions, and fouling.

Table 5: Seawater Coolers in LNG Plants: Lessons Learned Historical Problem Solution

Erosion of Copper Alloy Tubing

Replace with titanium. No velocity limitations. Replace with copper alloy, and control seawater flow within narrowly prescribed window: (Max velocities: Al/Br --1.5m/s, 90/10-- 2 m/s, 70/30-- 2.5 m/s.) Install high quality strainers and filters immediately upstream of the exchanger.

Scale fouling with under deposit corrosion

Increase seawater velocity to a minimum of 2 meter / sec. Maintain seawater exit temperature below 40 C to prevent scaling. Replace copper alloy tubing with titanium.

Sulfide corrosion Replace copper alloy tubing with titanium

Biological Fouling

Install strainers Hypo-chlorination system Install continuous cleaning system Increase seawater velocity to a minimum of 2 meter / sec.

Tube plugging due to debris and shells in sea water

Provide continuous cleaning sea water strainers immediately prior to the Coolers. Design pipe and exchangers to eliminate low velocity pockets where clams can grow.

Poster PO-36

PO-36.11

Low Fin Titanium Tubes Improve Seawater Coolers

The use of low finned tubing in refrigerant condensers and coolers is a commonly accepted practice because the added surface area per unit length of tube reduces the number of tubes and the size of the shells required. Furthermore, the higher the tubing material cost, the more significant the benefit of low fin tubes. In the case of titanium, the cost of a finned tube is approximately 25% more then a smooth tube per unit length, however, it is approximately half the cost of a smooth tube per square meter of surface area.

There are two new grassroots liquefaction plants under construction now, Snovit

LNG, and Yemen LNG, that utilize direct, once-through, seawater cooling and titanium low finned tubing. In the case of Snovit LNG, a compact shell and tube design called HELIFIN is utilized to reduce the heat exchanger size and minimize vibration potential. Instead of traditional perpendicular, segmental baffles, the refrigerant gas is guided by angled plates into a screw flow pattern. This allows a more efficient use of available pressure drop for heat transfer, and a closer support spacing for the thin wall titanium tubes. This technology is licensed by the ABB Lummus Heat Transfer Division and is combined with Fine-Fin® titanium tubing manufactured by High Performance Tube, Inc. Start up for this new LNG facility is planned for early 2007.

Titanium HELIFIN Heat Exchanger Under Construction (Photo courtesy of Koch Heat Transfer, SrL)

Poster PO-36

PO-36.12

Titanium Fine-Fin® tube. (High Performance Tube, Inc.) Future LNG Plants / Practical Considerations

LNG projects in the planning and front end engineering stage need to take into consideration many factors in the selection of cooling method. In addition to the design, cost, efficiency, environmental, safety, and reliability factors there are also the practical commercial factors. For example, it is anticipated that there will be a worldwide shortage of air cooler production capacity in the next 2-3 years due to the record backlog of LNG, refinery and petrochemical projects world-wide. New LNG plants need to factor this into the planning and early design phases when the selection cooling method is under review.

The preferred material of construction for seawater cooled heat exchangers is

titanium, however, this material is also in high demand for aerospace applications and other industrial applications. Supply shortages have affected delivery times for plate and frame heat exchangers which require titanium grade 1 material. It is recommended that the plate and frame exchangers required for indirect seawater cooling be placed in a special proactive procurement track so that orders can be issued at time of EPC commitment (or sooner, after the completion of the FEED package) in order to protect delivery.

Titanium shell and tube exchangers used in direct seawater coolers have not been affected by supply shortages since they are primarily grade 2 titanium which does not compete as directly with the aerospace demand for the purer grade 1 material. In light of this, current projects should consider the direct seawater cooling method as having less equipment lead-time issues compared to the indirect seawater method.

There are many alternative materials available for seawater cooled heat exchangers

but none that match titanium in terms of covering the complete range of natural seawater conditions and common variations in plant operating conditions. Below is a list of alternative materials in order of acceptability after titanium:

Super Ferritic Stainless: SeaCure, 29-4C Super Austenitic Stainless: Al6xn, 25-6mo Super Duplex 2507 70 /30 Cu-Ni 90/10 Cu-Ni

Poster PO-36

PO-36.13

The price for titanium grade 2 reached a record high in 2006 but has leveled off and is expected to drop gradually over the next 2-3 years. The outlook is positive because the titanium producers (primarily Russian, US and Japanese) have responded aggressively to market conditions by making large investments in new production capacity, which will enter market as early as 2008. Competing materials such as copper nickel and stainless steels have also risen sharply in price such that the relative cost comparison between materials has not changed as dramatically. Conclusion

Seawater cooling, and more specifically, direct seawater cooling remains a very attractive design approach for LNG liquefaction plants. The environmental and regulatory challenges today are considerably greater than those that existed during design of the first and second generation LNG plants, however, the benefits in terms of efficiency, compactness of design and overall cost savings remain valid. The consideration of a seawater cooling tower in place of once-through seawater system can reduce the environmental impact for some LNG sites and also provide needed cooling capacity expansion without dramatically increasing seawater intake and discharge. The use of direct seawater cooling has advantages over indirect seawater for the largest heat exchangers because it reduces capital cost, and the number of pieces of equipment to operate and maintain. Concerns about reliability and direct seawater cooling can be effectively addressed by reviewing the lessons learned from previous installations. The use of titanium low finned tubing in place of copper alloys can significantly improve reliability and efficiency for the main refrigerant condensing and compressor cooling services. The market conditions influencing the availability of materials and equipment related to each cooling method must be well understood by the LNG plant owners and engineering contractors in order for the most prudent and practical decision to emerge. References 1. Kua Siong Yan, “Impact of Sea cooling water (SWC) management and heat

exchanger design on tube failure in one-through sea cooling water system”. LNG 14 proceedings, Poster 25.1, 2004.

2. Riza, Farouk Mohamad. “ Metallurgy Improvement of MCR Coolers in Badak LNG

Plant”. Copyright PT. Badak, August 2000. 3. Pace, G.K. “Use Titanium tubes to create higher-capacity, corrosion-resistant

exchangers”. Hydrocarbon Processing, 1995 4. Small, William. “Titanium Design Permits Once-Through Seawater Cooling.” Oil and

Gas Journal, 1986.