Experimental Investigation of active heating in removal of wax deposits

Active heating is increasingly used as a cost-effective strategy for controlling wax deposition in offshore flow-lines. This study systematically investigated the effectiveness of active heating temperature in removing deposited wax with different characteristics in a flow loop. Two sets of experiments were conducted, targeting the removal of the deposits of different wax content (14% and 18%). In both sets of experiments, as the removal temperature decreased from wax appearance temperature (WAT) + 20% to WAT - 9%, the deposits underwent complete removal, partial removal, and no removal. The wax removal in all tests was found to be a rather swift process, with the majority of wax being removed within an hour. Interestingly, the removal of wax deposits was possible at temperatures lower than the WAT, as observed in the case in which 63% of the deposited wax was removed at WAT - 4%. As the wax content of the deposit increased, high removal temperatures were required. Unlike the trends observed in removing softer wax, the removal of harder wax appears to occur in two steps: a sudden removal was observed first, followed by a short period of time during which no removal occurred, followed by another sudden removal. Understanding this process in detail provides useful insight to manage the removal process more effectively and economically.

Automated summary

Active heating is found to be an effective method for controlling wax deposition in offshore flow-lines, with wax deposits being removed completely, partially, or not at all at different temperatures. The majority of wax can be swiftly removed within an hour, while higher removal temperatures are needed for deposits with higher wax content. In contrast to softer wax, the removal of harder wax seems to occur in two steps, with sudden removal followed by a period of no removal before sudden removal again.