Oil & Gas Vapor Recovery Unit

Technology: Adsorption + Desorption + Absorption

Applications: Hydrocarbon Vapor Recovery, VOC Emission Control, Solvent Recovery

Keywords: Vapor Recovery Unit, VRU, VOC Control, Hydrocarbon Recovery, Activated Carbon Adsorption, Oil Terminal Vapor Recovery, Loading Rack Emissions

Product Overview

Vapor Recovery Units (VRUs) are used to capture and recover hydrocarbon vapors generated during storage, transfer, loading, and processing operations. Typical applications include oil terminals, tank farms, refineries, petrochemical facilities, marine loading systems, and chemical manufacturing plants.

The adsorption-desorption-absorption process combines activated carbon adsorption with vapor concentration and liquid absorption technologies. This configuration allows hydrocarbon vapors to be separated from process gas streams and recovered for reuse or further processing.

System design is based on vapor composition, flow rate, operating pressure, recovery objectives, and applicable environmental requirements.

Key Features

Hydrocarbon Recovery

The system captures hydrocarbon vapors that would otherwise be emitted from storage and transfer operations, allowing recovered product to be returned to the process where appropriate.

VOC Emission Reduction

VRU systems are commonly used to support compliance with facility emission control requirements by reducing VOC releases from loading racks, storage tanks, and process vents.

Stable Operation Under Variable Conditions

The absorption stage helps accommodate fluctuations in vapor concentration and flow rate, supporting stable system performance across changing operating conditions.

Automated Process Control

PLC-based controls manage adsorption cycles, regeneration sequences, pressure regulation, and system monitoring. Operating parameters can be displayed and recorded through the operator interface.

Modular Design

Equipment can be supplied in skid-mounted configurations to simplify transportation, installation, and site integration.

Typical Technical Data

*Actual performance depends on vapor composition, operating conditions, and system configuration.

Process Description

1. Adsorption

Hydrocarbon-containing vapor enters the adsorption vessel and passes through activated carbon media. Organic compounds are retained within the carbon structure while the treated gas exits the system.

2. Desorption

Once the adsorption bed approaches saturation, regeneration is initiated using vacuum extraction, steam, or another selected desorption method. The concentrated hydrocarbon stream is collected for recovery.

3. Absorption

The concentrated vapor stream enters an absorption tower where hydrocarbons contact a circulating absorbent. The hydrocarbons dissolve into the liquid phase for subsequent recovery.

4. Product Recovery

The hydrocarbon-rich absorbent is processed through a separation system to recover usable product. The regenerated absorbent is then returned to the absorption loop.

Typical Applications

Oil Terminals and Tank Farms

Recovery of gasoline, diesel, condensate, and crude oil vapors generated during truck, railcar, and tank loading operations.

Refineries and Petrochemical Facilities

Control of hydrocarbon emissions from storage systems, process vents, wastewater treatment units, and transfer operations.

Marine Loading Operations

Recovery of hydrocarbon vapors generated during loading and unloading of marine vessels.

Chemical Manufacturing

Recovery of solvents and organic compounds used in production processes.

Equipment Scope

A typical VRU package may include:

• Activated carbon adsorption vessels
• Vacuum regeneration system
• Absorption column
• Circulation pumps
• Heat exchangers
• Vapor-liquid separation equipment
• PLC control system
• Instrumentation and safety devices

Actual scope varies according to project requirements.

Safety and Monitoring

Systems may include:

• Gas detection devices
• Pressure protection systems
• Flame arrestors
• Emergency shutdown functions
• Process interlocks
• Continuous monitoring instrumentation

Safety features are selected according to project specifications and applicable industry standards.

Engineering and Support Services

Services may include:

• Process evaluation
• System sizing and design
• Equipment manufacturing
• Installation and commissioning support
• Operator training
• Preventive maintenance programs
• Spare parts and technical support

For retrofit, commissioning, or maintenance work on vapor recovery systems, see this vapor recovery unit maintenance reference.

Project Consultation

Selection of a vapor recovery system requires evaluation of vapor composition, flow rate, recovery targets, operating conditions, and site requirements. A process assessment can be used to determine the most suitable recovery technology and equipment configuration for a specific application.