Vapour recovery and emissions control
Increasingly strict environmental controls worldwide are driving the requirement for vapour control of hydrocarbons during storage. A wide variety of options are available with advantages and disadvantages which have to be weighed up on a site-by-site basis
Significant health and safety problems can arise from emissions of volatile organic compounds (VOCs) while loading or unloading tankers, barges or handling vapours within a storage tank. Strong legislation, such as the Clean Air Act in the US and the Integrated Pollution Prevention and Control (IPPC) directive, which came into force in the EU in October 2007, is driving the installation of vapour recovery units.
The EU Directive 94/63/EC has specified vapour recovery rather than destruction in all truck, rail and barge loading operations since 1994. Recently, the German TA-Luft regulation reduced the vapour recovery target from 150mg/m3 emitted to a very challenging 50mg/m3. The Dutch environmental authorities are following suit, but may be a little less stringent on the petroleum vapour emission level set.
The US has legislated for vapour emission control since the late 1970s, but regulations vary from state to state, and use of combustion is widespread. The US Environmental Protection Agency (EPA) specifies 10mg/m3 of product loaded, but many states ask lower values. The states of New Jersey and California have very stringent regulations, and are currently considering specifying vapour control for all floating roof tank installations, in addition to existing rules for fixed roofs. VOC emission regulations also vary from country to country, to ensure that hydrocarbon vapours are contained in the storage device, incorporated into a vapour control device or destroyed.
Richard Nichols of California-based vapour recovery system supplier R.A. Nichols Engineering makes the point: ïIn the US, if your vapour recovery system goes down, the terminal must shut down. Fines are becoming so onerous that thereÍs no real payback on investment. So many terminal operators are going for vapour combustors, both standalone and online, rather than risk large fines. In the Midwest, many companies donÍt even bother with vapour recovery, but California is very concerned because of the smog problem.Í
