New insights into the evaluation of kinetic hydrate inhibitors and energy consumption in rocking and stirred cells

Highlights: • The performances of KHIs and synergists were compared in rocking and stirred cells. • The energy consumption by the cells was measured during hydrate formation tests. • The analysis of energy consumption was performed based on hydrate growth rate. • The suitable apparatus for evaluation of KHIs performance was determined. • The percentage of energy consumption for a weak and potent inhibitor was evaluated. The present paper aims at identifying suitable apparatus to perform KHIs test. Therefore, for the first time, the comparison of rocking and stirred cells was performed based on KHIs performance and energy consumption during hydrate formation experiments. Growth rate of hydrate, induction time measurements, and calculation of the kinetic parameter of aK∗ were applied for evaluation of KHIs and synergists in the rocking and stirred cells. The rate of hydrate formation showed that the performance of the KHIs and the synergists was more potent in the rocking cell compared to the stirred cell. Induction time measurements also indicate that hydrate nucleation is more retarded in the rocking cell compared to the stirred cell. However, new insights were revealed when energy measurements during hydrate formation experiments were applied. In the process of hydrate formation with weak inhibitors such as polyethylene glycols the consumed energy was up to 30 times greater than that in the rocking cell, although it was 3–8 times higher in the presences of Luvicap EG and synergists. In addition, analysis of energy consumption based on growth rate of hydrate determined that the rocking cell is preferred compared to the stirred cell for experimental development of KHIs.