Natural gas deacidification unit

Natural gas deacidification unit

The raw material gas enters the deacidification unit, which uses MDEA Solution formulaRemoving impurities from the raw gas using the method CO2 and H2S Waiting for acidic gases.

Natural gas enters from the lower part of the absorption tower and passes through the tower from bottom to top; *After regeneration MDEA 溶liquid(Poor liquid)）Entering from the top of the absorption tower, passing through the tower from top to bottom, and flowing in the opposite direction MDEA solutionFully contact with natural gas in the absorption tower, the CO2 Absorbed and entering the liquid phase, unabsorbedThe components are drawn out from the top of the absorption tower and enter the decarbonization gas cooler and separator. Gas from the decarbonization gas separatorEnter the raw material gas drying unit, and the condensate goes to the flash evaporation tank.

Processed natural CO2 Content less than 50ppmV，H2S Content less than 4 ppmV.

absorbed CO2 of MDEA The solution is called rich liquid and sent to the flash evaporation tower. The natural gas produced by depressurization flash evaporation is sent to the fuel system. After flash evaporation, the rich solution exchanges heat with the solution (lean solution) flowing out from the bottom of the regeneration tower, and then heats up to～ Go to the upper part of the regeneration tower at 98 ℃ and perform stripping regeneration in the tower until the lean liquid degree reaches the target.

The lean solution from the regeneration tower passes through the lean and rich liquid heat exchanger and lean liquid cooler, and is cooled to~After being pressurized by the lean solution pump at 40 ℃, it enters from the upper part of the absorption tower.

The gas at the top outlet of the regeneration tower enters the acid gas separator through the acid gas cooler, and the gas from the acid gas separator is sent to the acid gas discharge system. The condensate is pressurized by the recovery pump and sent to the flash separator.

The heat source of the regeneration tower reboiler is provided by the heat transfer oil from the heat transfer oil system. The main process equipment of this unit is absorption tower and regeneration tower.

Technical comparison:

natural gaspurifyThe process basically includes raw material gasDeacidification, dehydration, and mercury removalsystemWaiting for the manufacturing process,FirstAfter pre-treatment, the wellbore gas enters the purification block directly. The deacidification process (mainly referring to carbon dioxide and possible hydrogen sulfide) uses solvent absorption method, and the absorbent isMDEA； The dehydration process uses molecular sieves to remove trace amounts of water; The mercury removal process adopts the sulfur leaching activated carbon adsorption method;After natural gas purificationEnter the cold box for liquefaction.

Process selection of natural gas deacidification unit

As a raw material gas, natural gas must be purified before liquefaction. Removing acidic gases, moisture, and impurities from the raw gas, such asH₂S、CO₂TheH₂O. Hg, etc., to prevent them from freezing at low temperatures and blocking or corroding equipment and pipelines. Table 3.1-1 lists the pre-treatment standards and maximum impurity content for LNG plant feed gas.

Main equipment selection and supply:thisnetA chemical device is a complete set of equipment,Ensure stable and efficient operation of the device after completion. The principle of equipment design, manufacturing, and product selection is based on domestic standards、Mature technology and performance*.

Natural gas purification deviceProfessional Standards for Craftsmanship

HG20519-92 "Content of Chemical Process Design and Construction Drawings"

HG20546-92 "Design Content and Depth Regulations for Chemical Plant Equipment Layout"

HG/T20646.1-1999 "Design Content and Depth of Chemical Plant Pipeline Materials"

GB/T8163-2008 "Seamless Steel Tubes for Fluid Transport"

HG/T20592~20635-2009 "Steel Pipe Flanges, Gaskets, and Fasteners"

GB50235-2010 Construction Code for Industrial Metal Pipeline Engineering

GB50316-2000 (2008 edition) "Design Code for Industrial Metallic Piping"

HG/T20679-90 "Design Regulations for External Corrosion Protection of Chemical Equipment and Pipelines"

HG/T20546-2009 "Design Regulations for Equipment Layout of Chemical Plants"