natural gas liquefaction plants

Natural gas liquefaction plants

Our company began to develop LNG plant as early as in 1980s. By now, we have provided about 30 sets of LNG separation plants. The technique includes expander process, MRC mixed cold process, etc.

Natural gas pre-treatment and purification system including:

1. Desulphurization decarbonization system
Process: (MDEA+MEA) mixed amine method
(MDEA+ activator) MDEA method
Software: AMSIM which is recognized by Chinese authorities
Results: CO2<50ppm, H2S<4ppm

2. Dehydrating system
Dehydration by using 4A molecular sieve
Process by using three towers (or two towers): less regenerative gas is needed; more stable in operation
Molecular sieve dryer: it is designed in accordance with GB150 and tested by fatigue analysis

3. Mercury removal system: 10ng/nm³
The sulfur-loaded activated carbon is used to adsorb mercury, which can be used for 3-5 years. It is one tower or two towers, no need for regeneration. A filter is set behind the mercury removal system.

4. Aromatic hydrocarbon and heavy hydrocarbon removal system
From heavy hydrocarbon separator in the cold box, the heavy hydricarbon is separated and then adsorbed by scrubbing solution. After that, it goes out from tower bottom, gets separated, and at last gets stored in the storage tank.

Main processes/methods used for natural gas liquefaction by LNG plant:

1) expansion refrigeration circulation 
Nitrogen methane expansion or nitrogen double expansion with freon as pretreatment;
Mainly used for small type liquefaction plant with a capacity of 300,000 m³/day or below;

2) single mixed refrigerant circulation
It is divided into single stage throttling and multi stages throttling.
Liquefaction capacity: 300-2,000,000 m³/day

3) multi-refrigerant circulation 
Mixed refrigerant circulation with propane as pretreatment; liquefaction capacity: 2,000-10,000,000 m³/day.
Multi mixed refrigerant circulation with propane as pretreatment and mixed refrigerant circulation by nitrogen expansion for supercooling; liquefaction capacity: 10,000,000 m³/day or above;

Exterior view of the factory

Large production scale and output

The company covers an area of 87,000m3. We have pressure vessels in a complete range of capacities. Annually, we produce more than 800 storage tanks and more than 20 sets of gas plants. Our air separation plants all have reached a 40000Nm3/h level. Our 2000-10000m3 large cryogenic liquid storage tank was listed into national key scientific and technological projects. With a strong production capacity, we are able to cover urgent orders, as well as orders for high-performance equipment.

REFERENCE LIST OF NATURAL GAS LIQUEFACTION PLANTS