Institute of Petroleum Engineering

Centre for Gas Hydrate Research Publications

Abstract 116
Anti-Agglomerant and Synergism Effect of Quarternary Ammonium Zwitterions
Arjmandi, M., Ren, S., and Tohidi, B.
The 5th International Conference on Gas Hydrates, Trondheim, Norway, June 13-16 (2005).
In a previous study a new class of low dosage hydrate inhibitors, which are based on quaternary ammonium zwitterions and synthesised in Warwick University were tested in Heriot-Watt University in the framework of a joint project. Fourteen new hydrate kinetic inhibitors were screened by testing them in a hydrate Kinetic Rig at simulated offshore conditions and the performance of the best of them was compared with a commercial kinetic inhibitor, Poly (N Vinylpyrrolidone), PVP. In natural gas-water system the new inhibitor was comparable with PVP and in methane-water system it performed better than PVP. In this study, two of the above mentioned kinetic inhibitors were tested in the kinetic rig for further investigation of their properties as hydrate kinetic inhibitor synergist chemical and anti-agglomerant. The performance of the new low dosage hydrate inhibitors (LDHIs) was assessed by torque measurement of the Kinetic Rig stirrer in the presence and absence of the chemicals. The test results are very good, as addition of one of the new LDHIs (at 0.5 mass% concentration) to Poly (N-Vinylcaprolactam), PVCap (0.5 mass%) produced more than 53 hours induction time at 14.2 K subcooling in natural gas water system, while the induction time of the system without the new LDHI at 13.4 K was 1 hour. Furthermore, the new LDHIs demonstrated good anti agglomerant properties in a North Sea condensate, natural gas and water (30 vol.%) and the stirrer torque increase was almost half of that without any LDHI.

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