Development of PSA Tube Bundle Nitrogen Generating Modules with High-pressure and High-purity on Offshore Platforms

Nitrogen is already widely used in pipeline replacement and other related processes in the operations of LNG/LPG and offshore platforms. Now, it is being applied to processes in deep-water operations as well. In the paper, skid-mounted PSA nitrogen generation modules using high-pressure, high-purity tube bundles were designed and developed for application on offshore platforms. Firstly, the special requirements of offshore platforms for nitrogen production modules, such as high pressure and high purity and certification, are analyzed, and key technical difficulties are identified. Integrated tube bundle modules were used to design the PSA nitrogen reaction tower and pressure vessel, which effectively avoided certification difficulties and reduced costs. The proposed equipment was combined with a high-pressure molecular sieve for experimental research. A carbon molecular sieve (CMS) with pressure up to 1.7 MPa was selected, which exceeded that of mainstream CMSs (0.6-0.8 MPa). For the control scheme, an overlapping start-up mode was adopted for compiling the control program, which is realized through PLC + touch screen implementation + pneumatic control. The entire machine was integrated into 3 skid-mounted modules, and the relevant performance tests were carried out after manufacturing was completed. The output pressure was at least 1.4 MPa and the overall indicators met the design requirements. This project had introduced a new design concept and method for the development of skid-mounted high-pressure, high-purity nitrogen generation modules to be used on LNG/LPG and offshore platforms, and especially those modules required for deep-water operations.