【Q&A Question 279】2017.10.07

1. Pressure reduction and buffering 2. Separation of oil, gas, and water 3. Reducing the load on subsequent distillation processes

The buffer pressure prevents accidents where high pressure affects low pressure areas, thereby increasing the safety factor. It removes sulfides, water, and light hydrocarbons dissolved in the produced oil under high pressure, thus reducing the distillation load.

The buffer pressure prevents accidents where high pressure affects low pressure areas, thereby increasing the safety factor. It removes sulfides, water, and light hydrocarbons dissolved in the produced oil under high pressure, thus reducing the distillation load.

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 to sewage stripping.

The oil coming from the high-pressure separator is subjected to secondary separation at a lower pressure, allowing the gaseous components dissolved in the oil to escape; at the same time, the moisture contained in the oil can also be further separated here, to ensure the proper operation of the separation process.

Separate the reaction products into gas, oil, and sulfur-containing wastewater

The liquid from the cold high-pressure separator is flash-evaporated at low pressure to separate the dissolved hydrogen and light hydrocarbons; the gases are sent to a dry gas desulfurization unit, while the liquid obtained from the cold low-pressure separation is heated via heat exchange before being fed into the distillation system.

1: Connects the previous and subsequent content. The buffer pressure prevents the occurrence of high-pressure leaking into low-pressure areas, thereby increasing the safety factor. 2: It removes sulfides, water, and light hydrocarbons dissolved in the produced oil under high pressure, in order to reduce the distillation load.

1. The flash evaporation removes the light hydrocarbons, dry gas, as well as light components such as hydrogen sulfide and ammonia dissolved in the oil from a portion of the reaction effluent, thereby reducing the operating load on the distillation tower. 2. It serves as a buffer for the feed to the distillation column, preventing large fluctuations in the feed volume to the column. 3. The low-water-in-oil emulsion can separate out a large amount of reaction injection water and water generated by the reaction, thereby preventing distillation fluctuations caused by water in the feed to the distillation tower.

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 to sewage stripping. The working principle of the low-pressure separator relates to equilibrium vaporization in distillation processes; that is, the feed is subjected to reduced pressure and, within a container at a specific temperature and pressure, the vapor and liquid phases separate rapidly, yielding corresponding vapor and liquid products. The function of the low-pressure separator is, first, to separate the gas and liquid phases in the feed from the cold high-pressure separator; it flashes some of the gas phase components, thereby reducing the gas load on the distillation system ； Secondly, since the gas-phase components contain a high amount of hydrogen sulfide, removing some of this hydrogen sulfide in the low-pressure separator reduces equipment corrosion in the distillation system.