Natural gas dehydration issue

1. It should be the compressor outlet pressure minus 10°C at the coldest point of the pipeline. 2. It is recommended to consult relevant sources such as GPSA.

During normal operation of the triethylene glycol regeneration tower, the water vapor emitted from the top of the tower inevitably contains some light hydrocarbons. The proportion of these light hydrocarbons varies depending on the content of heavier components in the natural gas. These light hydrocarbons are usually released directly into the atmosphere, which not only pollutes the surrounding air but also increases the risk of fire accidents, as the bottom of the regeneration tower is equipped with an open-flame heater. During the renovation of the dewatering system at the Wendong gas lift boosting station, a condenser was installed at the outlet at the top of the triethylene glycol regeneration tower. The rich triethylene glycol stream coming out of the triethylene glycol absorption tower was used as a cooling source to condense all the water vapor and light hydrocarbons, which were then separated. This approach not only reduced air pollution but also allowed for the recovery of light hydrocarbons, achieving two goals at once. The regenerated lean triethylene glycol undergoes secondary heat exchange; after being pressurized by a glycol pump, it enters the natural gas dehydration tower. To reduce energy consumption and improve heat recovery, it is necessary to increase the area of the heat exchangers. However, this leads to an increase in the pressure required to feed the lean triethylene glycol into the pump, as the heating furnace operates at atmospheric pressure and the glycol pump is prone to cavitation. If a smaller heat exchange area is used to reduce pump resistance, the heat recovery rate decreases, and the load on the heating furnace increases accordingly, raising the overall energy consumption of the system. When designing this part of the process, the glycol circulation pump can be placed between the two-stage heat exchangers; this not only reduces the flow resistance at the inlet of the glycol pump but also increases the heat exchange area of the second-stage heat exchanger. At the same time, it is necessary to carefully calculate the pressure loss in the first-stage heat exchanger as well as the installation height of the glycol pump in order to prevent vacuum formation. The modified system recovers as much of the waste heat from the depleted triglycol as possible, thereby reducing energy consumption.

Are there any useful molecular sieves? How should the size of the container be designed for dehydration using liquid propylene molecular sieves, and what is the appropriate height-to-diameter ratio for the bed?