Construction and optimisation of an on-site nitrogen pressure swing adsorption process for Nuenz Ltd.
| dc.contributor.author | Peat, Kendrick | |
| dc.date.accessioned | 2024-12-13T03:04:53Z | |
| dc.date.available | 2024-12-13T03:04:53Z | |
| dc.date.issued | 2024 | |
| dc.description.abstract | Nitrogen is widely used as an inert gas in the chemical process industry to prevent oxidation. The abundant availability of atmospheric nitrogen has made air the primary feedstock for nearly all nitrogen production processes. The primary objective of this thesis was to construct and optimise an on-site nitrogen generation process for the company Nuenz. A literature review established that stripping reflux pressure swing adsorption using a carbon molecular sieve (CMS) adsorbent and a modified Skarstrom process cycle was the most suitable method for economic nitrogen production at the purity and volume relevant to the company. A pilot-scale stripping reflux pressure swing adsorption rig (pilot PSA rig) that produced high-purity nitrogen (500-5 ppm O2) was successfully constructed using off-the-shelf and in-house fabricated components. The effect of operating parameters and cycle configuration on process performance was experimentally investigated, especially the effect of cycle time, column aspect ratio, equalisation time, cutting time, temperature, productivity and pressure. The performance of the pilot PSA rig was assessed using the performance indicators (PIs): purity, mass efficiency, and productivity. Optimal operating parameters for the pilot PSA rig were established from experimental results. A trade-off between purity and mass efficiency was linked to half-cycle time, with shorter half-cycles enhancing purity, whereas longer half-cycles improved mass efficiency. An increased column aspect ratio enhanced purity without compromising mass efficiency or productivity. A short equalisation step enhanced all PIs of the pilot PSA rig with a 0.5 s equalisation yielding maximum purity improvements. A cut step enhanced mass efficiency and productivity, while a cut time that was 30% of the half-cycle time maximised purity. Low operating temperatures enhanced all PIs at shorter cut step times but caused a purity decline at longer cut step times. Mass efficiency was enhanced at the expense of purity when productivity was increased. However, operating at a short half-cycle time and higher productivity achieved the same purity and efficiency as operating with a longer half-cycle time and lower productivity. Higher operating pressures improved product purity at the expense of mass efficiency. However, a higher operating pressure increased productivity for a given product purity without compromising mass efficiency. An empirical model was established from experimental results, which demonstrated good agreement with purity readings at different cut times, half-cycle times, and productivities and showed good predictive power for predicting purity when a productivity 15% higher than the experimental range was used. | |
| dc.identifier.uri | https://hdl.handle.net/10092/107873 | |
| dc.identifier.uri | https://doi.org/10.26021/15584 | |
| dc.language | English | |
| dc.language.iso | en | |
| dc.rights | All Right Reserved | |
| dc.rights.uri | https://canterbury.libguides.com/rights/theses | |
| dc.title | Construction and optimisation of an on-site nitrogen pressure swing adsorption process for Nuenz Ltd. | |
| dc.type | Theses / Dissertations | |
| thesis.degree.discipline | Chemical Engineering | |
| thesis.degree.grantor | University of Canterbury | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Engineering | |
| uc.college | Faculty of Engineering |