The principles of high-pressure separators and low-pressure separators

The principle relies on the separation of the gas, oil, and water phases based on their differences in density. There are basically two types of structures: vertical tanks and horizontal tanks.

Three-phase separation at the gas-liquid interface takes place; since the high-pressure side is much higher in pressure than that of the split system, the equipment is usually equipped with a demister. The function of the low-pressure circuit is as follows: 1: To serve as a link between the upper and lower sections. The buffer pressure prevents the occurrence of high-pressure bleeding into low-pressure systems, thereby increasing the safety factor. 2: It removes sulfides, water, and light hydrocarbons dissolved in the produced oil under high pressure, thus reducing the distillation load.

Separators in hydrogenation: Conventional hydrogenation units (especially those dedicated to hydrogenation refining) are equipped only with cold high-pressure and cold low-pressure separation systems. The hydrocracking unit is equipped with hot high-split, hot low-split, cold high-split, and cold low-split processes. Different separator processes are set according to the properties of the raw materials, operating conditions, and product specifications. The basic principle of the separator is the three-phase separation of gas, oil, and water. 1) Thermal high-pressure separation: Thermal high-pressure separator. Upright. Gas-liquid two-phase separation. Its pressure is the pressure of the reaction system; its gas phase enters the cold high-pressure separator after being air-cooled ； Its liquid phase enters the thermal fractionator ； 2) Thermal low pressure: thermal low-pressure separator. Upright. Gas-liquid two-phase separation. Its pressure is usually around 3 MPa, and its gas phase enters the cold fractionator after air cooling ； Its liquid phase enters the hydrogen sulfide removal stripping tower and then proceeds to distillation. 3) Cold high-pressure separation: Cold high-pressure separator. Upright. Separation of gas, oil, and water phases. The gaseous phase at its top (mainly hydrogen) enters the circulating hydrogen gas-liquid separation tank, where it is circulated by a hydrogen circulation pump. Its oil phase enters the cold light fraction oil phase chamber. Its aqueous phase enters the cold low-boiling fractionation chamber. 4) Cold low-pressure separator: Cold low-pressure separator. Horizontal. Separation of gas, oil, and water phases. The gas phase undergoes desulfurization, while the oil phase also enters the hydrogen sulfide removal stripping tower and then proceeds to distillation. Its aqueous phase is sent for wastewater stripping.

Our cold low-temperature models seem to be vertical as well; what are the advantages and disadvantages compared to horizontal ones?

Since the separation surface area of a horizontal type is larger than that of a vertical type, the processing capacity of the horizontal type is higher. Generally, high-pressure separators are vertical, while low-pressure separators are horizontal.

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Vertical reactors have a long residence time for gas-liquid separation, resulting in good separation efficiency, but their separation area is small. Horizontal reactors have a large separation area and short separation time, but due to the short residence time, the separation efficiency is generally average. Mainly considering the need for good separation performance in both high-temperature and low-temperature scenarios, as well as in high-cold conditions, a vertical reactor was chosen. For low-temperature and low-cold conditions, where the requirements for separation performance are not as strict but a faster separation speed is needed, that is, a higher processing capacity is required, a horizontal reactor was selected.