(538h) Experimental Investigation of the Differences in Wax and Water Contents of Deposits for Oil-Water Emulsions Using Steel and Polyethylene Pipes

Wax deposition is one of the most common as well as most problematic issues in oil transportation pipelines. The presence of wax deposits can lead to an increase in resistance to fluid transport in the pipelines and an increase in pipeline transport costs. If wax deposits are not removed from the inner pipe wall of the transportation pipelines over a long time, the capacity of the pipeline will be reduced, and the safe operation will be threatened. In recent days, non-metallic pipelines have been increasingly used in the gathering and transportation pipelines in fields due to their excellent performance in the corrosion protection, However, few wax deposition investigations of oil-water emulsions in non-metallic pipelines have ever been conducted experimentally. In the present research, a self-designed indoor flow loop apparatus and oil-water emulsions with varied water content were used to investigate the wax content of deposits in two types of test sections (carbon steel and polyethylene) under laminar flow regime. After the experiments, the wax deposit layer in the test section was divided into two layers and sampled mechanically. Then, a differential scanning calorimeter (DSC) was used to measure the wax content of deposits under different operating conditions, and a dehydrating apparatus was used to measure the water content of the wax deposits. The results showed that under different operating conditions, the wax content of deposits in the steel test section was higher that of the deposits in the polyethylene test sections. As the increase of the wax deposition duration, the difference between the wax content of the deposits in the two types of test sections became smaller. In addition, the water content of the wax deposits in both test sections gradually decreased with the increase of wax deposition duration. The reasons for the difference between the wax content and water content of deposits in the two types of test sections were analyzed by calculating the radial mass flux of wax in the bulk flow and the adhesion of wax deposits on the inner surface of pipe wall. The results and analysis presented in this research can provide reference for the managing of wax deposition problems in the gathering and transportation pipelines in fields.