---
title: "Vacuum Phase-Change Indirect Electric Heater"
url: "https://xgthermal.com/products/vacuum-assisted-phase-change-indirect-heater/"
language: "en"
---

# Vacuum Phase-Change Indirect Electric Heater

Sealed phase-change heat transfer for crude oil and suitable multiphase oilfield preheating duties.

Equipment Overview

## Electric heat, delivered through a gentler interface.

The vacuum-assisted phase-change indirect electric heater transfers energy through a sealed intermediate-fluid chamber rather than exposing the process stream to energized electric elements. Vapor releases latent heat around the process coil, condenses and returns by gravity.

For low-temperature crude preheating, vacuum conditions allow water to operate within a controlled phase-change temperature window. Process-coil design, working-fluid selection, operating pressure and protection are reviewed around your specification.

[Discuss Your Requirements](https://xgthermal.com/contact.html)

![Vacuum phase-change indirect electric heater assembly](https://xgthermal.com/images/products/product-details/product1-detail-1.webp)

Equipment shown. Final configuration follows the approved process and design basis.

### Controlled heating interface

Wall temperature and heat flux considered for fouling-sensitive media.

### Sealed phase-change transfer

Evaporation and condensation transfer heat to the process coil.

### PLC + SCR control

Heat input, monitoring and site interfaces coordinated together.

Applications & Operating Conditions

## Preheat the process stream. Control the heating interface.

Crude properties, phase composition, pressure, flow and fouling tendency determine whether this heating route suits the duty.

### Crude gathering lines

Temperature conditioning for crude transfer and gathering duties.

### Tank circulation

Indirect preheating in storage-tank circulation arrangements.

### Separator & multiphase feed

Project-reviewed oil-gas-water mixtures and separator inlet streams.

### Process & gas preheating

Upstream heat-exchanger feeds and suitable natural-gas heating duties.

Heating Principle & Engineering

## Heat the working fluid. Let condensation carry the energy.

Electric elements heat the intermediate fluid in a sealed chamber. Vapor distributes energy to the process coil, condenses as it releases heat, and returns by gravity. The process stream remains within its own pressure boundary.

This route is selected to support a lower, more uniform heating interface for suitable fouling-sensitive streams. It does not remove the need to review fluid chemistry, heat flux, pressure drop, residence time and maintenance access.

-   Process pressure boundary designed separately from the intermediate-fluid chamber.
-   Working-fluid temperature and pressure window confirmed for each configuration.
-   Cold-region freeze protection and start-up conditions reviewed together.
-   Coil arrangement and flow path coordinated with medium properties and allowable pressure drop.

![Sealed intermediate-fluid evaporation and condensation around the process coil](https://xgthermal.com/images/products/product-details/bdrg260-phase-change-diagram-v2.webp)

Phase-change heat-transfer principle.

![Conceptual cutaway of process-tube helical guidance and swirling flow](https://xgthermal.com/images/products/product-details/bdrg260-spin-flow-diagram-v2.webp)

Conceptual process-side flow guidance. Final geometry follows the approved design.

01

### Outlet-temperature feedback

PLC regulation matches electric heat input to the agreed process setpoint.

02

### SCR power control

Stepless power regulation supports changing duty and operating conditions.

03

### Chamber & element monitoring

Shell temperature, element temperature and internal pressure monitored as specified.

04

### Station interfaces & protection

Permissives, alarms and Modbus TCP/IP or RTU communication coordinated with site requirements.

Working-Fluid Options

## Choose the temperature window before the final configuration.

Published ranges describe different design options. Working-fluid suitability and chamber conditions require project-specific review.

### Vacuum water phase-change

**60–90°C**

Low-temperature crude preheating; cold-region antifreeze protection reviewed as required.

### Dowtherm-based fluid

**180–300°C**

Medium-to-high-temperature duties with a separately selected operating window.

### High-temperature fluid option

**260–380°C**

Special duties subject to working-fluid limits, process conditions and safety review.

Crude oil anti-coking logic

## The goal is not hotter elements. It is safer heat delivery at the oil interface.

Heavy crude and oil-gas-water mixtures can form deposits when they meet localized high-temperature surfaces. In many direct electric or electromagnetic heating routes, raising outlet temperature often means raising the element or wall temperature first. XGTHERMAL's vacuum-assisted phase-change route changes that logic: heat is released by condensing vapor around the process coil, so the crude oil receives more even heat without direct contact with an energized heating element.

Conventional direct / high-surface heating**Higher element temperature**

Local hot spots may accelerate fouling, coking, cleaning demand, and unplanned maintenance.

XGTHERMAL vacuum phase-change route**Lower-temperature heating interface**

In low-temperature duties, vacuum water phase change releases latent heat around the coil for stable, low-fouling heating across crude feed duties, including separator feed service.

Operational value**Cleaner heat transfer path**

Less direct thermal stress on crude oil supports steadier outlet temperature and easier long-term operation.

Energy cost model

## A clearer route to lower heating cost where legacy systems waste energy at the heat-transfer surface.

When an existing direct electric, electromagnetic, or immersion-style heater relies on high surface temperature to force heat into crude oil, part of the operating cost is often hidden in overheating, fouling, cleaning, and oversized duty. A vacuum-assisted phase-change route can reduce the direct electricity cost by delivering heat more evenly at the process interface.

**Traditional high-surface heating**Baseline electricity cost index

100%

**Vacuum-assisted phase-change route**Modeled range after heat-transfer optimization

65–80%

Illustration only, not a guaranteed saving. For Central Asia screening, public business electricity prices are around US$0.075/kWh in Uzbekistan and US$0.079–0.086/kWh in Kazakhstan in recent datasets. At US$0.075/kWh, every 100,000 kWh of avoidable heating electricity equals about US$7,500 in annual energy cost. Final savings require the site's flow rate, inlet/outlet temperature, operating hours, fouling history, and actual electricity tariff.

Market comparison

## Gas-fired vacuum phase-change heater vs. all-electric phase-change heating

Many legacy vacuum phase-change systems use a burner and fuel-gas system. XGTHERMAL's All-Electric Vacuum-Assisted Phase-Change Heater keeps the familiar indirect phase-change principle, but removes the combustion package from the heater skid.

| Item | Gas-Fired Vacuum Phase-Change Heater | All-Electric Vacuum-Assisted Phase-Change Heater |
| --- | --- | --- |
| Heat source | Burner, fuel-gas train, ignition system, and flue arrangement. | Electric heating elements controlled through PLC + SCR power regulation. |
| Emissions on site | Requires combustion and exhaust handling. | Combustion-free, no on-site flue gas from the heater package. |
| Control response | Depends on burner modulation and combustion-system thermal inertia. | Stepless electric power control helps match heat output to outlet temperature. |
| Site utilities | Requires fuel gas supply and combustion auxiliaries. | Requires suitable electrical capacity and hazardous-area electrical design. |
| Maintenance focus | Burner, flame detection, gas train, and exhaust components need routine attention. | No burner, fuel-gas train, ignition system, or flue arrangement; removable electric elements simplify service. |
| Operating economics | Depends on fuel-gas availability, gas price, maintenance, and operating schedule. | Operating cost depends on local energy prices, but the all-electric route simplifies combustion-system maintenance and digital control. |

Not a conventional water-bath heater

## Vacuum phase-change heating is a more specialized indirect heating route.

For international buyers, this equipment may look close to an indirect electric water-bath heater at first glance. The key difference is the heat-transfer mechanism. A conventional bath relies mainly on sensible heat in the heated bath medium, while the vacuum-assisted design uses evaporation and condensation inside a sealed chamber to move heat rapidly to the process coil.

| Item | Conventional Indirect Water-Bath Heater | Vacuum-Assisted Phase-Change Indirect Heater |
| --- | --- | --- |
| Heat-transfer principle | Sensible heat transfer from heated bath medium to the process coil. | Latent heat transfer through evaporation and condensation in a sealed vacuum chamber. |
| Temperature behavior | Often depends on a larger bulk temperature difference to increase outlet temperature. | Designed to deliver stable heat at a lower, more uniform heating interface. |
| Crude oil suitability | Suitable for general indirect heating where bath inertia and maintenance are acceptable. | Better suited to crude and multi-phase feed heating where low wall temperature, anti-fouling behavior, and stable process conditions matter. |
| Design focus | Simple indirect heating package. | Specialized anti-coking indirect heating package for multi-phase media, separator feed, and general crude preheating processes. |

Technical reading

## Engineering references behind the heating principle.

These external materials combine general phase-change heat-transfer theory with oil-and-gas references on crude oil fouling, wall temperature, and heat flux. They are provided for technical reading, not as certification of any specific XGTHERMAL product configuration.

[**NASA Thermal Control: Heat Pipes**General principle: vaporization and condensation transport heat through a sealed working fluid.](https://www.nasa.gov/smallsat-institute/sst-soa/thermal-control/)[**Crude Oil Fouling under Different Operating Conditions**Oil-and-gas context: applied heat flux can affect how quickly fouling forms in crude-oil preheat exchangers.](https://www.sciencedirect.com/science/article/abs/pii/S2451904923000951)[**Crude Oil Fouling in Preheat Exchangers**Oil-and-gas context: wall temperature is a key parameter in crude-oil fouling and asphaltene deposition models.](https://www.sciencedirect.com/science/article/pii/S1359431105004187)[**Variables Affecting Crude Oil Heat-Exchanger Fouling**Operational context: field data links fouling behavior with wall temperature, flow velocity, and wall shear rate.](https://www.cetjournal.it/index.php/cet/article/view/CET1870321)

Technical Data & Delivery Scope

## Review the details that matter.

Published options provide a starting point. Final values and certification requirements are confirmed for your project.

[Request a Datasheet](https://xgthermal.com/contact.html)

### Specifications

| Specification Parameters | Specification Details |
| --- | --- |
| Rated Voltage | AC380V 50HZ (Customizable) |
| Rated Power | 0~3000KW |
| Inlet/Outlet Specification | Customizable according to working conditions |
| Control Mode | PLC, Single-chip Microcomputer, Digital Display Meter (Optional) |
| Alarm Mode | Over-temperature Alarm, Over-pressure Alarm, Low Flow Alarm, Low Liquid Level Alarm, Electrical Fault Alarm (Optional) |
| Design Pressure | 0~45MPa |
| Control Cabinet | Explosion-proof/Non-explosion-proof |
| Protection Class | IP65 |
| Explosion-Proof Grade | Exdb IIB T1~T6Gb Exdb IIC T1~T6Gb |

### Standards & Certification

| National Standard | Corresponding IEC Standard | Corresponding GOST R Standard |
| --- | --- | --- |
| GB/T3836.1 Explosive Atmospheres - Part 1 | IEC 60079-0:2017 Explosive Atmospheres - Part 0: General Requirements for Equipment | GOST R 51330: This series of standards covers electrical equipment in explosive gas atmospheres, including requirements for design, construction, test methods and marking, equivalent to GB3836.1.2-2021. |
| GB3836.2 Explosive Atmospheres - Part 2: Equipment Protected by Flameproof Enclosures "d" | IEC 60079-1:2014 Explosive Atmospheres - Part 1: Equipment Protected by Flameproof Enclosures "d" | GOST R 51332: This series of standards involves increased safety electrical equipment, similar to GB3836.3-2021, specifying design and construction requirements to prevent ignition in explosive gas atmospheres. |
| Q/SXGBH02-2023 BDRG-□ Explosion-Proof Electric Heater (3000kw) | - | - |
| Q/SXGBH09-2022 BDRG-□ Explosion-Proof Electric Heater (500kw) | - | - |
| Q/SXGBH11-2022 BXM(D)P-WK-□ Series Explosion-Proof Power Distribution Box | - | - |

Certification availability depends on the final equipment configuration, destination market, hazardous-area classification and third-party assessment. Listed standards describe engineering and documentation support, not blanket certification for every configuration.

### Supply Scope

| Name | Origin/Brand | Remarks |
| --- | --- | --- |
| Shell | Shenyang Xinguang Electric Manufacturing Co., Ltd. | - |
| Heating Element | Shenyang Xinguang Electric Manufacturing Co., Ltd. | - |
| Control Cabinet | Shenyang Xinguang Electric Manufacturing Co., Ltd. | Explosion-proof/Non-explosion-proof |
| Electrical Components | Delixi, Chint | PLC, Circuit Breaker, Contactor, Thyristor, Relay, Isolating Barrier, etc. |
| Instruments | Chuanyi, Anhui Tiankang, Beijing Tiantai | Pressure Transmitter, Temperature Transmitter, Liquid Level Gauge, Flow Meter, etc. |

Selection Support

## From operating conditions to a practical equipment review.

Share the process duty and medium properties. Coil heat transfer, chamber conditions and phase-change-fluid selection require a coordinated engineering review.

### What to share with our team.

Send your datasheet, process specification or drawings. For gas-containing streams, include phase composition and operating pressure; a simple liquid-flow calculator does not validate this heating arrangement.

-   Process medium, phase composition and property data
-   Minimum, normal and maximum flow
-   Inlet and required outlet temperature
-   Process-side operating and design pressures
-   Allowable pressure drop and connection standards
-   Fouling history and permitted wall temperature
-   Ambient range and freeze-protection requirements
-   Working-fluid selection and operating temperature window
-   Hazardous-area classification and destination requirements
-   Site electrical supply, controls and remote interfaces

[Send Your Specification](https://xgthermal.com/contact.html)

### Common engineering questions.

Is this a conventional water-bath heater?

The equipment is indirect, but its sealed intermediate chamber uses evaporation and condensation to transfer latent heat to the process coil. A conventional water bath primarily transfers sensible heat from the bath medium.

Does the process stream contact the electric elements?

No. Electric elements heat the intermediate working fluid. The process stream flows through a separate pressure boundary and receives heat indirectly.

Does every configuration operate under vacuum?

Vacuum water phase-change is used for the low-temperature heating route. Higher-temperature working-fluid options require their own operating pressure and temperature design; they should not be assumed to use the same vacuum conditions.

Can it eliminate coking or guarantee energy savings?

Lower and more uniform wall temperature can help manage fouling-sensitive service. Actual deposition and energy use depend on fluid properties, flow, heat-transfer conditions and operation. Savings require a project-specific baseline and assessment.

Can it be used for gas-containing or multiphase streams?

Suitable duties can be reviewed using phase composition, flow, pressure and temperature data. Gas pressure-reduction duties also need a station process calculation to establish the required downstream temperature.

What information is needed for selection?

Share process conditions, medium properties, flow range, required temperatures, pressure ratings, ambient conditions and site electrical requirements. The process coil, working fluid, controls and documentation are reviewed together.

Manufacturing & Project Experience

## Review the equipment. Then review the field application.

Manufacturing since 1992, with 120+ projects delivered across our industrial heating equipment range.

[Review Our Capabilities](https://xgthermal.com/about.html)

![Vacuum phase-change heaters supplied for the Xingang Oilfield project](https://xgthermal.com/images/products/product-details/product1-detail-2.webp)

### Oilfield Vacuum Phase-Change Heating Project

A field application replacing conventional steam heating with vacuum phase-change electric heating in an oilfield gathering and transportation system. Review the equipment arrangement and project context.

[View Project Details](https://xgthermal.com/projects/vacuum-phase-change-oilfield-heating/)