High Quality China Natural Gas Decarbonisation Factories - Molecular sieve dehydration skid – Rongteng

Description

Molecular sieve dehydration skid is a key device in natural gas purifying or natural gas conditioning. Molecular sieve is an alkali metal aluminosilicate crystal with framework structure and uniform microporous structure. When the feed gas containing trace water passes through the molecular sieve bed at room temperature, the trace water and mercaptan are absorbed, thus reducing the water and mercaptan content in the feed gas, realizing the purpose of dehydration and desulfurization. the adsorption process of molecular sieve is usually carried out at low temperature and high pressure, while the desorption regeneration is carried out at high temperature and low pressure. Under the action of high temperature, clean and low pressure regeneration gas, the molecular sieve adsorbent releases the adsorbate in the micropore into the regeneration gas flow until the amount of adsorbate in the adsorbent reaches a very low level, and has the ability to absorb water and mercaptan from the feed gas, realizing the regeneration and recycling process of molecular sieve.
Molecular sieve method is a kind of deep dehydration method, which is often used in low-temperature condensation separation process, such as natural gas condensate (NGL) recovery and dehydration process in the production of liquefied natural gas (LNG). In addition, molecular sieve dehydration is also used in the production of compressed natural gas for automobile fuel.

Molecular sieve dehydration is generally applicable to the following occasions:
a. Where the dew point of natural gas is required to be lower than – 40 ℃.
b. It is suitable for hydrocarbon dew point control of lean high pressure natural gas.
c. Natural gas is dehydrated and purified at the same time.
d. When the natural gas containing H2S is dehydrated and dissolved in glycol, it will cause the emission of regeneration gas.
e. When LPG and NGL dehydration need to remove trace sulfide (H2S, CO
COS, CS2, mercaptan) at the same time.

Flow chart

Fixed bed adsorbers are used for molecular sieve dehydration, so the unit should have at least two adsorbers, one in adsorption dehydration stage, the other in regeneration and cooling stage. When the capacity of the unit is very large, the multi tower process can also be arranged.
Technical parameters

Inlet gas condition

1 Flow 290.1X104 Nm3/d
2 Inlet Pressure 4.86-6.15 MPa
3 Inlet Temperature -48.98℃
Outlet gas condition
4 Flow 284.4X104 Nm3/d
5 Outlet pressure 4.7-5.99 MPa
6 Outlet temperature -50.29℃
7 H2S ≤20g/m3
8 CO2 ≤3%
9 Water dew point <-5℃