The conflict between natural gas supply and maintenance?
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Background of the issue: There is a failure in the gas pipeline in gaseous form, requiring it to be shut down for repairs; yet it is still necessary to continue supplying gas to customers... Experts, please advise: Is it feasible to use liquefied natural gas trucks as a temporary replacement for the original gaseous natural gas pipeline to supply gas to customers? If feasible, what form should the tank truck take? How should natural gas be vaporized? How should the pressure of vaporized natural gas be controlled? What else should be taken into consideration during the operation? This post was last edited by leefun on 2009-4-13 16:22]
In this case, a mobile gasification unit should be used to supply gas; just do a search online – there are many such units available. The mobile liquefied natural gas vaporization and supply unit features a skid-mounted design, consisting of a cylinder bank skid and a vaporization and pressure regulation skid. The chassis of each skid is fabricated by welding channel steel and steel plates; the liquefied natural gas cylinders, air-temperature vaporizers, overpressure shut-off valves, and pressure regulators are all mounted on the fixtures located on the chassis. Four lifting hooks are installed at the corners of each skid to facilitate the loading and unloading of the cylinder bank skid onto motor vehicles. The pipes connecting the two skids are made of stainless steel hoses.
It depends on the number of users; if gas supply is to be provided through urban pipeline networks, a peak-shaving station is necessary. The equipment involved includes low-temperature storage tanks (whose size can be determined based on the amount of gas required), forced vaporizers, and, if a large volume of gas is needed, water-bath vaporizers as well. There is also a pressure regulation system, and the pressure level can be adjusted according to the pressure in the storage tanks. For smaller-scale applications, an LNG truck combined with a vaporizer is usually sufficient to meet the requirements. Of course, someone is needed to control the flow rate of LNG, as it can be very dangerous if the LNG liquid enters carbon steel pipes without proper vaporization.
The key is to figure out how to control the temperature of the natural gas exiting under such a approach. LNG vaporization stations typically have strict systems for controlling the exit temperature; it is dangerous if the temperature is below the range suitable for the use of the materials and equipment. Unless there is a sophisticated gas temperature control system.