Refinery dry gas and liquefied gas desulfurization mostly use amine liquid desulfurization, which uses amine liquid to absorb H2S and CO2 in the gas for purification purposes. The solvent converted into alcohol amine salt releases H2S and CO2 after heating and stripping, and the amine liquid is recycled after regeneration. In the process of amine desulfurization, in addition to absorbing H2S and CO2, it often reacts with other substances present in the system or carries solid impurities into the upstream pipeline, including thermally stable salts, sulfides, iron filings, etc. Easy to cause problems such as foaming and scaling, resulting in serious consequences such as reduced efficiency and equipment damage. Therefore, amine liquid filtration is particularly important in gas desulfurization. Lefilter filtering, combined with practical application experience, has proposed optimized solutions for amine desulfurization processes, solving many problems on the production line.
A complete amine liquid filtration system usually adopts a multi-stage series filtration scheme to achieve the best purification effect.
1. Mechanical filter (first level/protection level)
Function: Remove most large solid particles (such as>10-25 μ m), protect downstream precision filters, and extend their lifespan.
Type: Usually bag filter or side leakage filter. The structure is simple, easy to replace, and has strong dirt holding capacity.
2. Precision filter (second stage/core precision filter)
Function: Deeply remove small solid particles (usually up to 1-10 μ m).
Type: Adopting wound, melt blown, or foldable filter cartridges. This is the core unit to ensure the cleanliness of the amine solution, which can effectively capture small corrosion products and crystalline salts.
3. Activated carbon filter (third stage/adsorption unit)
Function: Specially used for adsorbing soluble hydrocarbons (oils), amine degradation products, and surfactants, it is the most effective means of inhibiting amine foaming.
Type: Tank filled with specialized wooden or coal based activated carbon. Activated carbon needs to be replaced or regenerated regularly.
Solution for ammonia liquid filtration:
1. Raw material gas filtration: Before amine cleaning, solid and liquid impurities contained in the raw material gas should be removed first. Fly ash should be filtered using a coalescer to effectively intercept solid and liquid impurities such as rust and iron sulfide.
2. Amine recovery: The use of a coalescer can recover the amine carried in the gas, avoiding amine loss and increasing operating costs.
3. Reduce foaming of amine solution: polypropylene FSH filter element with high contaminant capacity shall be used for filtering rich/lean amine solution to remove solid particles, and then through activated carbon filter to remove gas in amine solution to prevent foam and other impacts on downstream equipment.
4. Clean system technology guarantee: Lefilter's SelfClear ○ R speed cleaning system is the best solution for handling large amounts of viscous deformation and fine particles in rich liquids;
| Parameter Category |
Specific Parameter |
Description / Example / Common Range |
Importance |
| I. Basic Process Parameters |
|
(Describes the basic condition of the amine liquid to be treated) |
★★★★★ |
| 1. Amine Type |
MDEA, DEA, MEA, Formulated Amines, etc. |
Critical, affects material compatibility |
| 2. Process Stream |
Lean Amine / Rich Amine / Mixed Amine |
Critical, rich amine contains more hydrocarbons, requires robust carbon filtration |
| 3. Total Circulation Rate |
e.g., 200 m³/h |
Critical, for determining slipstream ratio |
| 4. Design Slipstream Flow Rate |
e.g., 10-40 m³/h (Typically 5%-20% of total circulation) |
Core design parameter |
| 5. Operating Temperature |
e.g., 40 - 60 °C (Maximum temperature must be specified) |
Affects filter media material selection |
| 6. Operating Pressure |
e.g., 0.6 - 1.0 MPa |
Affects the pressure rating of the filter vessel |
| 7. Inlet/Outlet Pipe Size |
DN50, DN80, etc. |
Basic mechanical design input |
| II. Fluid Contamination Profile |
|
(Describes the impurities to be removed, ideally with lab analysis report) |
★★★★★ |
| 1. Solids Content |
e.g., 50 - 500 ppm |
Determines the dirt holding capacity and pre-filtration level required |
| 2. Particle Size Distribution (PSD) |
Percentage of >10μm, 5-10μm, <5μm particles |
Core basis for determining the filtration rating of each stage |
| 3. Hydrocarbon (Oil) Content |
e.g., 50 - 1000 ppm |
Determines the size and quantity of the activated carbon vessel |
| 4. Heat Stable Salts (HSS) Content |
e.g., <1% wt |
Assesses system health; activated carbon is effective on some HSS precursors |
| III. Filtration System Design |
|
(Defines the specific equipment configuration based on the above parameters) |
|
| 1. Number of Stages |
Two-Stage (Mechanical + Polish) / Three-Stage (Mech. + Polish + Carbon) |
Three-stage is the recommended standard configuration |
| 2. 1st Stage: Mechanical Rating |
100, 50, 25, 10 μm |
Protects downstream polish filters |
| 3. 2nd Stage: Polish Filtration Rating |
10, 5, 3, 1 μm |
Core polishing unit, 5μm or 3μm is common |
| 4. 3rd Stage: Activated Carbon Type |
Coal-based, Wood-based, 4x8 Mesh, 8x30 Mesh, etc. |
Specifically for adsorbing hydrocarbons and degradation products |
| 5. Number of Filter Vessels |
Single / Multiple in parallel |
Ensures continuous operation and change-out without shutdown |
| 6. Number of Filter Elements/Bags |
Quantity per vessel, e.g., 3, 7, 12 elements |
Determined by flow rate and pressure drop |
| 7. Design Pressure Drop (Clean) |
< 0.05 MPa |
Indicator of system energy consumption |
| 8. Maximum Allowable Pressure Drop |
0.1 - 0.2 MPa (Differential pressure alarm setpoint) |
Trigger for element change-out |
| IV. Materials & Design Standards |
|
(Ensures corrosion resistance and long service life) |
★★★★ |
| 1. Filter Vessel Material |
CS + Lining / 304 SS / 316 SS |
316SS is preferred, especially for the rich amine side |
| 2. Element/Bag Cage Material |
304 SS / 316 SS |
Avoids corrosion |
| 3. Filter Media Material |
Polypropylene (PP), Glass Fiber, PTFE, etc. |
PP is common; PTFE for high temp or harsh conditions |
| 4. Sealing Material |
EPDM, FKM etc. |
Must be compatible with amine service |
| 5. Design Standard |
ASME, GB150, PED, etc. |
Pressure vessel certification standard |
| V. Control & Automation |
|
(Requirements for ease of operation) |
★★★ |
| 1. Control Mode |
Manual / Automatic Differential Pressure Control |
Automation is recommended to reduce manual effort |
| 2. Instrumentation |
Differential Pressure Gauge, Pressure Gauge, Temperature Gauge |
Standard configuration |
| 3. Interfaces |
4-20mA signal output, Alarm switches |
For connection to DCS/PLC system |
| 4. Drainage Method |
Manual / Automatic |
|
Audited Supplier 
){kind=link}