Why Recover VOC Vapour?
VOCs are part of the large hydrocarbon family, a vast array of aliphatic, aromatic hydrocarbons, their halogenated derivatives, alcohols, ketones and aldehydes.
VOCs are highly reactive hydrocarbons and participate in atmospheric photochemical reactions. Some of them have negligible photochemical activity; however, they play an important role as heat trapping gases in the atmosphere. VOC of both primary and secondary origin in ambient air have immense importance as they have direct as well as indirect effects on climate change, ecology and human health.
In presence of oxides of nitrogen and sunlight, VOCs form ozone and other products.
VOCs are cause of concern firstly due to its role in formation of ground level ozone and smog and secondly due to some of them being carcinogenic, mutagenic and teratogenic in nature. Adverse effects of ozone on human health, crop viability and yields are well documented.
The threats of ground level ozone to humans vary with exposure. During short term, high intensity exposure, health effects can include irritation of the nose and throat, coughing, painful breathing, and reduced lung function. Long-term exposure to smog at low levels can affect lung elasticity and the lungs ability to resist disease, effectively ageing lungs prematurely. The effects of ozone on fauna is similar to its effect on humans. As for flora, ozone damages leaf tissue. This can greatly affect the ability of plants to grow and thrive. Visible damage to leaf tissue includes discoloration, black and white spots, as well as leaf loss.
Some VOCs have lower reactivity and thus long atmospheric life times and can be classified as Persistent Organic Pollutants (POPs). Other VOCs are Hazardous Air Pollutants (HAPs) by virtue of their toxicity.
International concerns regarding VOCs arise due to their ability of long-range transport, distribution and accumulation in various components of environment and their toxic nature.
Implementing VOC vapour processing systems in terminals, removes the hazardous atmosphere around the loading facilities. This highly improves the working environment for the operators, truck drivers and other personnel involved in the loading operation, by removing the toxic and smelling VOC substances.
By reclaiming the emitted VOC vapour from the extraction, transport, storing and refining of crude oil, and the distribution of gasoline and petrochemicals, the losses of valuable energy resources, and the associated significant economic losses are reduced or eliminated. It is estimated that up to 1% Vol. of the liquid, evaporates and is lost from crude oil extraction to the end-user driving the vehicle, if no means of emission prevention is taken.
The investment in a VOC vapour recovery unit will pay back depending on which application the system is used for; Units recovering taxed gasoline products vapour, have a typical payback period of one to two years, while recovering untaxed gasoline products and crude oil vapour, gives a slightly longer payback period of up to five years.
By capturing the VOC vapour
for treatment and avoiding its escape to the atmosphere, potentially explosive environments are avoided in storages, loading facilities and service stations, which improves the safety level in
these areas drastic.