Validation and Improvement of the Horizontal Pipe Separator Model

Abstract

Abstract Horizontal Pipe Separators (HPS©) are used for separation of oil from oil-water mixture. It can be an attractive alternative to the vessel type separator owing to its simplicity, ease of construction, installation and operation and its lower price. An experimental and theoretical investigation on the (HPS©) were conducted. New experimental data and mechanistic modeling are presented to show the effect of different variables such as mixture velocity and water cut on the performance of the separator. A HPS facility, consisting of a 0.0762 m ID 10.3 m long horizontal pipe has been designed and constructed. Five observation boxes are installed along the horizontal pipe to observe the development of the oil/dispersion and water/dispersion interfaces throughout the pipe. A wide range of experimental data was acquired for oil-water mixture flow behavior, and length of entry region for the oil and water separation in the Horizontal Pipe Separator was also investigated. A total of 34 runs were conducted for mixture velocities of 0.08, 0.13, 0.20 and 0.30 m/s with water cuts between 10 to 90%. The experimental data confirm that the higher the mixture velocity, the longer is the entry region required for separation. On the other hand, when increasing the water cut, the water separation is more efficient. Similarly, decreasing the watercut results in an easier separation of the oil phase. For low water cuts (10 to 30%) and higher mixture velocities (>0.3 m/s), no separation between the phases was observed. The Gassies (2008) model has been validated and improved for water continuous flow by developing correlations for two of the Gassies model's input variables, namely, the turbulent decay time and the oil volume fraction in the dense packed zone. For water continuous phase, the comparison between the improved model prediction and the experimental data shows very good agreement for the water/dispersion interface and also for the oil/dispersion interface at low mixture velocities.