Types of Industrial tanks
There are 8 different types of tanks that are used above ground. You are certainly familiar with some of these tanks because their considerable size can be seen even from afar. Most Industrial tanks are cylindrical in shape with the axis oriented perpendicular to the sub grade. Pressure tanks are different since they are usually horizontally oriented and spherically shaped to ensure structural integrity at high pressure.
Fixed-roof industrial tank
One of the most popular Industrial tanks that are widely used today is the fixed-roof tank because it is more cost effective to construct and is generally considered as the minimum acceptable equipment for the storage of various liquids. A typical fixed-roof tank is made from a cylindrical steel shell that is usually fully welded with a dome-shaped roof that is permanently installed on the tank shell. Fixed-roof Industrial tanks that are used for both the petroleum and chemical industries have gauge hatches/sample wells, float gauges and roof manholes for ease of accessibility although it can be a potential source of hazardous emissions.
Horizontal industrial tank
Horizontal Industrial tanks are typically installed above ground but they can also used for underground purposes. Steel with a fiberglass inlay or fiberglass-enforced polyester are the most common materials from which horizontal tanks are made from. Generally horizontal tanks are small with a length of no greater than 6 times its diameter to maintain structural integrity. Horizontal tanks that are installed underground are cathodically protected to ensure corrosion resistance. The most common cathodic protection on tanks is the sacrificial anode system that will only require inspection once every three years from a qualified inspector. For refineries and petroleum industries, internal cathodic protection is now replaced by corrosion inhibitors.
LNG Storage tanks
LNG or liquefied natural gas needs a specialized type of storage tank for above ground installation and for LNG carriers. The most common characteristic of the LNG storage tank is its ability to store the gas at a very low temperature of -162oC. Usually the storage tanks are made up of two containers; one with the ability to store gas at low temperature and the other as insulation. In the LNG storage tank, if the vapors are not released, it will result into a buildup of pressure and temperature that is why LNG at its liquid state has to be stored a very low temperature. In order to ensure that temperature will remain constant, the boil-off gas has to be allowed to escape from the tank. This is referred to as auto-refrigeration. However, it is very critical to avoid auto-refrigeration of pressure tanks that are not designed for low temperature operation.