Superior seedlings propagating growth pattern of hydrates

Abstract

Facing complicated hydrate formation processes and dozens of models’ establishments with an attempt to unravel the hidden mechanisms, many parameters have been considered from lots of viewpoints affecting specific hydrate growth process. It appears that incorporating various models into a unique uniform one to account for all formation behaviours seems impossible. Another line of thought is then investigated, i.e. if skipping over complicated specific growth process, whether there is some direct relation between initial nucleation and finally-formed bulk hydrate crystals. Within an experimental apparatus with specially designed structures, one-sided cooling method only from top was used to drag hydrate crystal structures growing upwards from gas-liquid interface. Complete formation processes from initial gas dissolution to final growth termination were then observed through video cameras. It is found that like pea seedlings growth pattern, finally formed bulk crystal structures are in fact propagated from a few initial hydrate embryos and there are significant linear relations between initial nucleation dynamics and final hydration numbers. Some special positions of equipment possess obvious superiority to induce hydrate embryos occurrence, e.g. the four corners of reactor, among which the two adjacent to this reactor wall with more rapid heat conduction are facilitated. The trend lines directions of linear relations are completely opposite, meaning that mechanisms dominating specific growth processes of hydrate crystals are actually disparate under different methods. Final formation reaction efficiency can be achieved by increasing initial nucleation dynamics substantially. Some instructive suggestions on practical applications related with hydrates, e.g. industrial process design, prediction to blocking position owing to hydrates, hydrate formation inhibition by means of physical method etc., may be proposed through these summarized conclusions.