VOC & BTEX Removal from Cargo Vapours

The Growing Challenge of VOC & BTEX Emissions from Cargo Vapours

Volatile Organic Compounds (VOC) and BTEX (Benzene, Toluene, Ethylbenzene and Xylene) are critical emission components on crude oil tankers, product tankers and chemical carriers. Every operation that involves loading, unloading, heating, stripping or ventilating cargo tanks produces vapour streams rich in these hazardous compounds. These vapours cannot be discharged into the atmosphere without proper treatment — not only due to strict port regulations but also because BTEX compounds pose significant environmental, safety and health risks.

Many ports, especially in Northern Europe, North America and Asia, now enforce strict VOC reduction rules for tankers. The shipping industry is therefore moving towards dedicated gas treatment systems that remove VOC and BTEX from vapours before release. Wet scrubbers have become one of the most reliable and effective ways to treat these emissions onboard.

Ravebo designs advanced scrubber systems specifically engineered for VOC and BTEX removal from cargo vapours, using proven industrial gas cleaning technology adapted for the maritime environment.

Understanding VOC and BTEX in Marine Cargo Vapours

Cargo vapours are formed from the natural evaporation of hydrocarbons during storage and handling. Depending on the cargo type—ranging from crude oil and gasoline to aromatics, condensates and chemical products—the vapour mixture may contain dozens of VOC compounds.

These compounds are hazardous for human health, contribute to photochemical smog, and can create explosive atmospheres if released in high concentrations. BTEX compounds in particular are linked to carcinogenic risks and are tightly regulated in modern ports.

As environmental restrictions tighten, shipowners must invest in effective emission control systems that guarantee compliance while maintaining operational efficiency.

How VOC/BTEX Scrubbers Work

Wet scrubbers for VOC and BTEX operate on the principle of mass transfer: the contaminated vapour stream is brought into close contact with a liquid phase—typically water or an oxidative reagent—allowing the pollutants to be absorbed or chemically neutralized.

While VOC compounds are generally hydrophobic, many BTEX molecules are partly soluble, and their solubility improves greatly when the scrubbing solution is chemically enhanced. For high-efficiency removal, Ravebo systems use combinations of:

• Multi-stage packed beds
• Oxidative additives (e.g., H₂O₂) for aldehydes
• Alkaline or acidic reagents depending on cargo type
• High-efficiency droplet separators
• Instrumentation monitoring VOC loading

These technologies ensure that VOC and BTEX components are captured before the treated gas is safely discharged to atmosphere or directed to a vapour processing system.

Typical Cargo Vapour Treatment Process

Below is a simplified process flow showing how cargo vapours move through a tanker's vapour handling system and into a dedicated BTEX scrubber.

The scrubber sits after vapour collection and condensation, ensuring optimal removal efficiency with manageable flow rates. This configuration is standard for many tanker operations and can be tailored to fit vessel layout constraints.

Design Considerations for VOC/BTEX Marine Scrubbers

1. Cargo Type and Composition

Every cargo type has its own VOC profile. Aromatic-rich cargoes like gasoline and condensates produce vapours dominated by BTEX, while crude oils may have a broader mixture of VOCs and sulphur components. Ravebo scrubbers are custom-designed to match the specific chemistry of each vessel’s cargo portfolio.

2. Flow Rate Variability

Vapour volumes during loading can vary significantly depending on pumping rate, temperature, and cargo volatility. High-capacity demisters and adaptive liquid distribution ensure stable removal even during peak vapour loads.

3. Corrosion Resistance

Hydrocarbon vapours, especially those containing aromatics or acidic components, require corrosion-resistant construction materials. Ravebo systems are built using lined carbon steel or high-grade stainless steels to ensure long-term durability at sea.

4. Safety Integration

VOC-rich vapours can reach flammable limits. Proper grounding, flame arrestors and inert design principles are crucial. Ravebo scrubbers integrate seamlessly with the vessel’s existing safety systems, inert gas systems and VCS controls.

5. Port and Class Compliance

Many ports now enforce VOC reduction targets, while classification societies require onboard systems to meet specific design and safety criteria. Ravebo supports shipyards and operators through the full compliance process.

Benefits of Removing VOC/BTEX from Cargo Vapours

Shipowners increasingly recognize that VOC and BTEX control is not only a regulatory necessity but also a reputational asset. Cleaner operations strengthen relationships with terminals, reduce operational restrictions and ensure smoother port calls.

Why Shipyards and Tanker Operators Choose Ravebo

Ravebo specializes in industrial-grade gas cleaning technology adapted for the maritime sector. Our scrubbers are engineered to handle high VOC loadings, challenging BTEX concentrations and variable flow rates while maintaining compact footprints suitable for shipboard installations.

With decades of experience in VOC control, BTEX scrubbing, hazardous gas treatment and maritime system integration, Ravebo delivers solutions that combine chemical performance, mechanical reliability and operational safety.