Application and Advantage of KDP Plate Heat Exchanger in Edible Oil Processing

Application and Advantage of KDP Plate Heat Exchanger in Edible Oil Processing

Plate heat exchangers have advantages such as efficient heat transfer, energy saving, and compactness in edible oil processing, and are widely used in processes such as heating, cooling, deodorization, and crystallization of oils and fats. The core lies in the reasonable selection of boards and sealing gaskets to ensure high temperature resistance, corrosion resistance, and long-term stability. The following provides a detailed explanation from four aspects: process application, plate selection, and gasket selection:

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Process Application of KDP Plate Heat Exchanger in Edible Oil Processing

Heating process

Application stage:

Preheating before crude oil refining, heating up the hydrogenation process (usually to 180-220 ℃).

Requirement:

High temperature stability to avoid local overheating that may cause oil oxidation or coking.

Cooling process

Application stage:

Hydrogenated oil rapid cooling (from high temperature to below 50 ℃ to form β 'crystal form), cooling after fractional crystallization.

Requirement:

Fast and uniform cooling to prevent crystal coarsening.

Deodorization process

Application link:

Heat recovery of the inlet and outlet oil of the deodorization tower (preheating the feed oil through a heat exchanger while cooling the deodorization oil).

Requirement:

Sealing in high vacuum environment to prevent air infiltration.

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KDP Key factors for selecting plate materials

The core material of plate heat exchangers needs to meet the requirements of high temperature resistance, corrosion resistance, and high strength.

The commonly used materials are as follows:

Material TypeCharacteristicsApplicable ScenariosLimitations
316L stainless steelUniversal choice, resistant to weak acids and bases, high cost performanceNeutral oils and fats (such as soybean oil and rapeseed oil)Not resistant to high chloride ions (such as seawater cooling conditions)
254SMO Super Stainless SteelContains 6% molybdenum, resistant to pitting and crevice corrosion (applicable when Cl ⁻ concentration is high)Operating conditions with residual chlorine or seawater coolingHigh cost
Titanium (Ti)Strong acid resistance (such as citric acid cleaning), seawater corrosion resistanceSpecial high acid value oils or harsh cleaning conditionsExpensive price
Nickel based alloy (Hastelloy)High temperature and strong oxidizing medium resistanceHigh temperature deodorization (>230 ℃) or high acid value greaseOnly used for extreme working conditions

KDP Selection criteria for sealing gaskets

The rubber pad needs to withstand grease, high temperature, and cleaning agents. Common materials and applicable conditions:

Gasket materialTemperature resistance rangeOil resistanceApplicable process
NBR (Nitrile Rubber)-20~120 ℃Resistant to mineral oil, but prone to swelling when in long-term contact with vegetable oilLow temperature cooling (<100 ℃)
EPDM (Ethylene Propylene Diene Monomer)-40~150 ℃Resistant to polar oils and fats, not resistant to hydrocarbon solventsDeodorization heat recovery (neutral oils and fats)
FKM (fluororubber)-20~200 ℃Resistant to almost all oils and solvents, anti-agingHigh temperature deodorization and hydrogenation (>180 ℃)
PTFE coated gasket-100~260 ℃Completely inert, but with poor elasticity, needs to be matched with a metal skeletonStrong corrosive medium (such as fatty acid condensation)
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Key considerations :

Temperature adaptability :

FKM is the preferred choice for high-temperature conditions (such as deodorized oil heat exchange).

Chemical compatibility :

The long-term stability of the rubber pad in specific oils (such as palmitic acid, oleic acid) needs to be tested.

Sealing structure :

The rubber gasket needs to match the groove of the board, and the commonly used "Clip on" type is easy to disassemble and clean.

Advantages of KDP Plate Heat Exchangers in the Edible Oil Industry Compared to

Other Heat Exchangers

Plate heat exchangers (PHEs) offer significant advantages over other heat exchanger types (such as shell-and-tube, spiral, and double-pipe) in edible oil processing, particularly in heat transfer efficiency, energy savings, hygienic design, and maintenance convenience. Below is a detailed comparative analysis.

1、High Heat Transfer Efficiency & Energy Savings

High Turbulence Design

PHEs:

Corrugated plates create complex flow paths, inducing turbulent flow (Re > 200) even at low velocities. Heat transfer coefficients (K-values) reach 3000–7000 W/(m²·K), 3–5 times higher than shell-and-tube exchangers (500–2500 W/(m²·K)).

Vs. Shell-and-Tube:

Flow in the shell side tends to be laminar, requiring higher velocities or baffles to enhance heat transfer, increasing energy consumption.

Close Temperature Approach (Small ΔT_min)

PHEs achieve 1–3°C terminal temperature difference (e.g., between hot fluid outlet and cold fluid inlet), while shell-and-tube exchangers typically require 5–10°C.
Application Example:

In edible oil deodorization, PHEs recover heat from deodorized oil more efficiently, reducing steam consumption by 20–30%.

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2、Compact Design, Saving Space & Cost

Small Footprint

For the same heat duty, PHEs occupy 1/5–1/10 the space of shell-and-tube exchangers, ideal for space-constrained edible oil plants (e.g., low-ceiling workshops).

Example: Cooling 100 m³/h of edible oil requires ~2 m² for a PHE vs. ~10 m² for a shell-and-tube unit.

Less Material Usage

Plate thickness is only 0.5–0.8 mm (vs. 1.2–2 mm for shell-and-tube tubes), reducing stainless steel usage by >50% and lowering costs.

3、Hygienic Design, Compliant with Food Safety Standards

Deadleg-Free Structure

Smooth flow channels in PHEs prevent oil residue buildup and bacterial growth, complying with FDA and EHEDG certifications.

Vs. Spiral Heat Exchangers: Spiral channels trap oil residues and are harder to clean.

CIP/SIP Compatibility

Supports clean-in-place (CIP) and sterilization-in-place (SIP) using NaOH, HNO₃, etc., while shell-and-tube units require disassembly for manual cleaning.

Food-Grade Materials

Plates use 316L stainless steel or titanium, and gaskets use FKM fluorocarbon or EPDM rubber, meeting food contact standards (e.g., EC 1935/2004).

4、Operational Flexibility for Process Adaptability

Modular Scalability

Heat transfer area can be adjusted by adding/removing plates (e.g., +20% plates for capacity expansion), whereas shell-and-tube units require full replacement.

Multi-Stage Configurations

PHEs can be arranged in series/parallel for heating-cooling-heat recovery integration (e.g., stepwise temperature control in palm oil fractionation).

Handling Viscosity Changes

Edible oils thicken at low temperatures (e.g., palm oil viscosity ≈80 cP at 25°C). PHEs optimize corrugation angles (e.g., 60°) to reduce pressure drop, while shell-and-tube units suffer from uneven flow.

5、Easy Maintenance & Lower Lifecycle Costs

Quick Disassembly

Plates and gaskets can be dismantled by one operator (just loosening clamping bolts), with cleaning/replacement in <2 hours. Shell-and-tube units require specialized teams and 1–2 days of downtime.

Localized Repairs

A single damaged plate can be replaced at 5–10% of total cost, whereas shell-and-tube tube bundle leaks often require full replacement (30–50% cost).

Low Fouling Tendency

High turbulence minimizes fouling, extending cleaning cycles to 3–6 months (vs. 1–3 months for shell-and-tube).

6、Limitations of Other Heat Exchangers & PHE Countermeasures

Heat Exchanger TypeKey DisadvantagesPHE Advantages
Shell-and-TubeLow efficiency, bulkyHigh efficiency, compact design
Spiral PlateHard to clean, non-expandableFully detachable, modular scalability
Double-PipeSmall surface area, high energy useMulti-plate stacking, low-flow turbulence
Scraped-SurfaceOnly for ultra-high viscosity, costlyHandles medium-high viscosity (≤500 cP)

7、Typical Application Examples

Palm Oil Fractionation & Crystallization

PHEs rapidly cool oil to crystallization temps (20–30°C), preventing coarse crystals, with lower pressure drop than spiral exchangers.

Soybean Oil Deodorization Heat Recovery

Recovers >90% heat from deodorized oil (vs. 70–80% for shell-and-tube).

Hydrogenated Oil Quenching

Cools from 200°C to <50°C, 40% faster response than double-pipe exchangers.

8、Selection Considerations

Despite their advantages, PHEs require caution in:

Crude Oil with Solids: Install filters (≥100 mesh) to prevent clogging.

Ultra-High Temperatures (>250°C): Use special frames (e.g., galvanized carbon steel) to avoid thermal deformation.