Jacketed Vessel Heat Transfer Calculator

Commercial-grade calculator for estimating heat transfer rates (Q), Overall Coefficients (U), and LMTD in jacketed process vessels. Suitable for Batch Reactors, Crystallizers, and Storage Tanks in the Chemical, Pharma, and Food industries. Supports advanced configurations including Half-Pipe Coils and Dimple Jackets with customizable fouling factors.

Vessel & Jacket Geometry

Unit System

Jacket Configuration

Vessel Inner Diameter ($D_i$) (m)

Wall Thickness ($t_w$) (m)

Heat Transfer Length ($L$) (m)

Jacket Inner Dia (Calculated) (m)

Jacket Outer Diameter ($D_{j,o}$) (m)

Process Conditions

Flow Strategy

Process Inlet ($T_{p,in}$) (°C)

Process Outlet ($T_{p,out}$) (°C)

Utility Inlet ($T_{j,in}$) (°C)

Utility Outlet ($T_{j,out}$) (°C)

Coefficients & Fouling Factors

Process Film Coeff. ($h_p$) (W/m²°C)

Process Fouling ($R_{f,p}$) (m²°C/W)

Jacket Film Coeff. ($h_j$) (W/m²°C)

Jacket Fouling ($R_{f,j}$) (m²°C/W)

Wall Conductivity ($k$) (W/mK)

Thermal Analysis Results

Total Heat Duty (Q)

Overall Coeff (U)

W/m²°C

LMTD

°C

Parameter	Value

Engineering Guide: Jacketed Process Vessels

A comprehensive overview of heat transfer mechanics, jacket selection, and operational factors for heavy industrial applications.

Jacket Configurations

The choice of jacket heavily impacts heat transfer efficiency ($U$) and structural integrity.

Conventional: Simple annular space. Low turbulence unless baffled. Best for low-pressure steam.
Dimple Jacket: High turbulence due to dimples. Cost-effective and allows thinner vessel walls.
Half-Pipe Coil: Welded pipes. Extremely high pressure capability and high velocity/turbulence. Ideal for thermal oil.

The Governing Equation

Heat transfer is defined by the unified equation:

$$ Q = U \times A \times LMTD $$

This relates total duty ($Q$) to the area ($A$), thermal efficiency ($U$), and temperature driving force ($LMTD$). Optimization involves maximizing $U$ through agitation and selecting the right $LMTD$ via flow arrangement.

Thermal Resistances

The Overall Coefficient ($U$) is the inverse sum of all resistances:

$$ \frac{1}{U} = \frac{1}{h_{inner}} + R_{f,in} + \frac{t}{k} + R_{f,out} + \frac{1}{h_{outer}} $$

Every layer counts. A thin layer of scale (fouling) can reduce heat transfer by 50%!

Agitation Dynamics

Without agitation, a stagnant boundary layer forms at the vessel wall, acting as insulation. Agitators (Turbines, Anchors, Helical Ribbons) scour this layer.

Rule of Thumb: For viscous fluids, scrapers are required to prevent product burn-on and maintain high $h_p$.

Fouling Factors ($R_f$)

Design must account for "dirty" conditions (End-of-Cycle). Using clean coefficients will result in an undersized reactor.

Water: 0.0001 - 0.0002 m²°C/W
Polymers: > 0.0005 m²°C/W

Flow Arrangement

Counter-Current: Utility flows opposite to process. Higher LMTD, higher efficiency. Preferred for most designs.

Co-Current: Utility flows with process. Lower LMTD, but safer for temperature-sensitive products to avoid thermal shock at the inlet.

Frequently Asked Questions (FAQ)

What determines the Overall Heat Transfer Coefficient (U)?

The Overall Heat Transfer Coefficient (U) is a composite value determined by the convective heat transfer coefficient of the process fluid inside the vessel, the convective coefficient of the fluid in the jacket, the thermal conductivity and thickness of the vessel wall, and the fouling factors on both the process and jacket sides. Agitation speed, fluid properties (viscosity, density), and jacket geometry (half-pipe vs. conventional) significantly influence these values.

Why is LMTD important in jacketed vessel calculations?

The Logarithmic Mean Temperature Difference (LMTD) represents the effective temperature driving force for heat transfer. Unlike a simple arithmetic mean, LMTD accounts for the non-linear temperature profile along the length of the vessel, providing a more accurate calculation of the total heat transfer rate (Q), especially in counter-current flow arrangements.

When should I use a Half-Pipe Coil Jacket instead of a Conventional Jacket?

Half-Pipe Coil jackets are preferred for high-pressure applications and when high velocity and turbulence in the heating/cooling medium are required to improve heat transfer. They offer structural reinforcement to the vessel wall, allowing for thinner shell walls compared to conventional jackets, which are better suited for lower pressure, high-volume flow applications.

How does fouling affect the performance of a jacketed vessel?

Fouling creates an additional insulating layer on the heat transfer surfaces, increasing thermal resistance. This drastically reduces the Overall Heat Transfer Coefficient (U), meaning the vessel requires more time or a larger temperature difference to achieve the same heating or cooling duty. Regular maintenance or using appropriate fouling factors in design is essential.

Can this calculator be used for batch reactors?

This calculator provides a steady-state snapshot based on inlet/outlet temperatures. For batch reactors, where vessel temperature changes over time, this tool can estimate the instantaneous heat transfer rate at specific process points (e.g., peak exotherm), but dynamic simulation is required for a full cycle analysis.