MOBILE NITROGEN PUMPER - A VALUABLE TOOL

摘要

This paper describes a unique piece of equipment for delivering nitrogen gas. This equipment is used for supplying nitrogen on a temporary basis and capable of delivering an extremely wide range of pressure, flow, and temperature requirements. In the electric utility industry, "temporary nitrogen supply" has been mostly associated with the use of banks of pressurized cylinders or tube trailers. Both have definite limitations with overall volume capacity and flow rates. These delivery systems tend to be time consuming, require multiple refill deliveries, and lack cost effectiveness. The general awareness of the existence of mobile nitrogen pumping equipment and the potential value it provides is relatively limited within the electric power industry. Recently, however, this equipment has been used successfully as a cost saving alternative for selected applications. One such example is to replace natural gas for fuel line blow cleaning and "target testing" during the construction phase of natural gas fired combustion turbines. The mobile nitrogen pumping equipment effectively duplicates the flow and sonic velocities achieved using natural gas while conforming to the established "target testing" specifications. The primary benefits of using nitrogen in lieu of natural gas or air are cited to be enhanced safety, environmental considerations, and overall time/cost savings. A description of this equipment is offered including the flow rate, pressure, and temperature specifications. Additionally, examples are given of a program that predicts nitrogen gas velocities throughout the natural gas delivery piping system under steady flow conditions. This includes velocity changes as the piping system diameter changes. Specific data is offered comparing the velocity differences between natural gas and nitrogen under the same steady state flow rate conditions. Case studies are offered that detail the successful use of this mobile nitrogen pumping equipment for line blowing and "target testing" during the pre startup phase of combined cycle plants.