Marine

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Detailed Explanation of KDP Plate Heat Exchangers in Ships: Applications and Process Flow

1. Marine PHE Applications:

Primarily for cooling/heating (central cooling, fuel heating, oil cooling).

2. Process Flow:

Includes seawater-freshwater exchange, staged fuel heating, and high-viscosity oil cooling.

3. Material Selection:

Seawater/high-sulfur: Titanium Gr2 or 254SMO

Low-sulfur/freshwater: 316L

High-temp/pressure oil: 2205 Duplex

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Key Applications in Marine Systems

Plate heat exchangers (PHEs) are widely used in ships for the following systems:

ApplicationFunctionTypical Parameters
Central Cooling SystemUses seawater to cool freshwater for engine/auxiliary cooling- Seawater side: 25-35°C
- Freshwater side: 70-90°C
- Heat capacity: 5-20 MW
Lubricating Oil CoolingCools main/auxiliary engine oil to prevent overheating- Oil inlet: 80-100°C
- Cooled oil: 50-60°C
- Viscosity: 68-150 cSt
Jacket Water CoolingMaintains engine jacket water temperature for stable operation- Inlet: 85-95°C
- Outlet: 75-85°C
- Temp. control accuracy: ±2°C
Fuel Oil HeatingHeats heavy fuel oil (HFO) to reduce viscosity for combustion- Fuel inlet: 40-50°C
- Heated to: 120-150°C
- Sulfur content: ≤3.5%          
HVAC SystemsCools refrigerant/cooling water in ship air conditioning- Refrigerant side: 5-10°C
- Cooling water side: 20-30°C

Typical Process Flow in Marine PHEs

Central Cooling System (Most Common)

A[Seawater Pump] --> B[Filter (100μm)] --> C[PHE (Primary Side)]

D[Low-Temp Freshwater] --> E[Control Valve (PID)] --> C[PHE (Secondary Side)]

C --> F[Engine Cooling System]

Key Parameters:

Seawater velocity: 1.0-1.5 m/s (prevents biofouling)

Freshwater velocity: 0.5-0.8 m/s (reduces pressure drop)

Fouling factor: ≤0.00005 m²·K/W (seawater side)

Fuel Oil Heating (High-Sulfur Environment)

A[HFO] --> B[PHE (Hot Side)]

C[Steam/Heat Medium] --> D[PHE (Cold Side)] --> E[Fuel Injection System]

Key Parameters:

Fuel velocity ≥1.2 m/s (prevents sulfur deposits)

Staged heating (40°C→80°C→120°C)

Lubricating Oil Cooling (High-Viscosity Fluid)

A[Hot Oil] --> B[PHE (Wide Gap Design)] --> C[Cooled Oil]

D[Seawater/Freshwater] --> E[PHE] --> F[Discharge/Circulation]

Key Parameters:

Oil velocity: 0.3-0.6 m/s (prevents coking)

Cooled oil temp.: 50-60°C

Material Selection for Marine KDP Plate Heat Exchangers (Detailed Examples)

(1) Material Selection Criteria

Marine PHE plates must meet:

Corrosion resistance (especially for seawater/HFO)

Mechanical strength (vibration/shock resistance)

Weldability (laser welding compatibility)

Cost-efficiency (titanium is expensive but long-lasting)

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Comparison of Common Plate Materials

MaterialSuitable MediaCorrosion ResistanceTemp. LimitCostTypical Marine Use
316L StainlessLow-sulfur fuel, freshwaterResists Cl⁻ ≤200ppm, not for seawater≤120°CLowHVAC, low-sulfur fuel heating
254SMOSeawater, high salinityResists Cl⁻ ≤50,000ppm (super austenitic)150°CMediumCentral cooling (seawater side)
Titanium Gr2Seawater, high-sulfur fuelImmune to Cl⁻, resists sulfur corrosion≤200°CHighFuel heating, seawater cooling
2205 DuplexGlycol, high-temp waterResists Cl⁻ ≤5000ppm, stress corrosion-resistant≤180°CMedium-HighJacket water cooling, thermal oil

Application-Specific Examples

Central Cooling (Seawater-Freshwater)

Recommended Material:

254SMO (seawater side) + 316L (freshwater side)

Reason:

254SMO withstands high chloride levels (50,000 ppm)

316L reduces cost on the freshwater side

Fuel Heating (High-Sulfur HFO)

Recommended Material:

Titanium Gr2

Reason:

Titanium is virtually immune to sulfur corrosion (safe even at ≤3.5% sulfur)

Long service life reduces maintenance costs

Lubricating Oil Cooling (High Viscosity)

Recommended Material:

2205 Duplex Steel

Reason:

Resists oil oxidation corrosion

High mechanical strength for high-pressure systems

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Summary

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Marine PHE Applications:

Primarily for cooling/heating (central cooling, fuel heating, oil cooling).

Process Flow:

Includes seawater-freshwater exchange, staged fuel heating, and high-viscosity oil cooling.

Material Selection:

Seawater/high-sulfur: Titanium Gr2 or 254SMO

Low-sulfur/freshwater: 316L

High-temp/pressure oil: 2205 Duplex

Our Core Strengths

In the petrochemical industry, equipment needs to withstand high temperature, high pressure, corrosion, scaling and other multiple tests. We are the preferred supplier of heat exchanger solutions for harsh working conditions due to the following core advantages:

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Customized design

Optimized heat transfer solutions according to petroleum/chemical process requirements

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Diversified products

Full range of plate heat exchangers, condensers, evaporators, etc.

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High reliability

Strict quality control, adapt to high temperature, high pressure and corrosive environment.

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Full life cycle service

From selection to maintenance, to ensure long-term stable operation.