Removing VOC From API1650 Storage Tanks

Ensure compliance with environmental guidelines for hydrocarbon tanks using NAT Oil & Energy’s VOC abatement systems

Reducing emissions such as harmful volatile organic compounds (VOCs) is a key consideration as storage terminals look to clean up their sites, especially as environmental regulations get stricter. NAT Oil & Energy (Denmark) provides a full range of tank fittings and tank vents with odour filters, VOC abatement systems (odour removal) and accessories for storage tanks, that meet EU directives, local legislation and customer-specific requirements. The company has also recently applied for its VOC filter to be approved for use in Singapore and Gibraltar. Furthermore, VOC abatement filters and tank vent systems can completely remove odours – ideal for hydrocarbon storage facilities that might have unpleasant smells. Years of know-how and field experience have positioned NAT Oil & Energy (Denmark)’s products as some of the best choices for environmental protection. So, can a VOC abatement filter work for you?

VOC Abatement Filters

Any tanks that are to be fitted with a VOC abatement filter must be built to API 650 standards, and maintained in accordance with API 653 or EEMUA159 (alteration repair and maintenance of tanks). The dimensions of the filter depend on the tank size, surface area and maximum pump rate for each tank. The tank’s pumping rates are important factors for the correct design of the filter surface, in order to remain within the maximum allowable pressure/vacuum during the operation. Breather valves are installed parallel to the adsorption filter, with settings complying to the maximum allowable pressure and vacuum of each tank to avoid break down and mechanical damage. In the case of tank overfill, mechanical damage or blockage by dirt in the adsorption filter, the breather valves will ensure continued operation and the tank ventilation will continue to function in accordance with the specifications for each individual application.

Safety Options For Tank Vent Filters

Depending on environmental legislative requirements, or if the hydrocarbon concentration is higher than 50 gram/m³, an additional safety option may be required. There are five options: 1: Forced Ventilation Forced ventilation is recommended for tanks with high evaporation, such as light products or products with a low flash point. The option can be fitted with a backup system. 2: Automatic Shut-Off Valve The shut-off valve option is triggered by sensors for either carbon monoxide, temperature, or both, and can be installed between the filter and the tank to ensure that a rise in temperature in the filter, a hot spot, will be isolated from the tank at a set-point well below the flash point of the tank content. 3: Water Mist System A water mist system can be inserted in the filter to cool it or, in emergencies, drench the active carbon; preventing or extinguishing a fire inside the filter, which could have been caused by hot spots. 4: Flame Arrestor A flame arrestor can be inserted between the filter and the tank to prevent vapours from igniting inside the filter. A flame arrestor does not function as a fire protection by itself, and therefore it is recommended that other measures are taken to ensure that an ignition (hot spot) is extinguished either by a built-in fire protection system as per above or by an on-site emergency response team. 5: PLC Automated Control Cabinet This option enables various alarm settings and reaction patterns to be programmed in combination with one or more of the above options.

Customising Tank Filter Systems

Customisation requires some collaboration between a storage operator and NAT Oil & Energy (Denmark). For simple installations, the company can calculate the dimensions and other data for the filter and breather valves from simple information. Larger or more complex installations will require a site visit to inspect the tank(s) and possible grouping of filters. The custom-designed tank vent system has a carbon odour filter, that eliminates odour problems from storage tanks for oil and oil products, thereby avoiding complaints and claims from neighbours, particularly in residential areas.