97% Efficiency Methane Gas Recovery System Unit With Custom Design

Absorption-membrane-Adsorption Technology for Vapor Recovery Unit

Summary

Vapor Recovery Unit is to collect the organic vapor discharged during the manufacturing, storage, loading and unloading processes of various industries and recycle it by means of condensation, adsorption, absorption, membrane separation, etc. so as to finally satisfy the emission standards and create certain economic benefits for the end user.

The Membrane Separation Process separates different composition taking advantage of their ability of penetrating the membrane. The Absorption–membrane–Adsorption Technology is suitable for treatment of medium to high concentration oil vapor, with no limitation to flow volume and vapor types. It is featured by small footprint.

Principle / Flow Procedure

The Membrane Separation Process separates different compositions taking advantage of different diffusion coefficient in membrane. As special polymeric membrane allows oil vapor to penetrate first, when the gas mixture is driven by pressure difference, the oil vapor penetrates the membrane and get recovered while air or nitrogen is blocked.

The associated gas is pressurized by a liquid ring compressor and led into the absorption tower for touch with the opposite flowing absorbent, then most of hydrocarbon composition shall be dissolved and absorbed;

The oil gas mixture pressurized by liquid ring compressor flows into the absorption tower and is exposed to absorbent flowing in opposite direction, where most hydrocarbon compositions are dissolved and absorbed. The remaining oil gas mixture of low concentration flows out of the tower from the top and enters the membrane system. High concentration oil gas penetrating the membrane returns to the absorption tower, while the air or nitrogen containing little oil vapor blocked by the membrane is delivered into small adsorption tank for further treatment. The Desorption Process adopts the dry screw vacuum pump for vacuum desorption. The oil vapor desorbed will be led into the absorption tower for further treatment.

Structure & Parameter (typical project)

Advantage

1. Software: ASPEN for process calculation, SW6 for equipment calculation, 3D CADworx for design of the skid;
2. High efficiency organic composite membrane featured by high recovery rate
3. High efficiency structured packing and low absorbent consumption;
4. Multi point temperature monitor on the adsorption tank, equipment safety shall be assured;
5. Dry screw vacuum pump used for desorption, high vacuum degree, no contamination of oil or water, wear free operation;
6. Delivered as a skid to reduce site installation work;
7. Fully sealed blower and flanged connection in the skid to achieve zero leakage
8. ExdIIBT4 or ExdIICT4 explosion proof

Applied data for an typical project

• Concentration of emission: Compliance with GB31570-2015 <Standard of pollutant emission for oil refinery industry>, GB31571-2015 <Standard of pollutant for petrochemical industry> and the related local standard.
• Details:

Benzene ≤ 4mg/m³,

Toluene ≤ 15mg/m³,

Xylene ≤ 20mg/m³,

Ethylbenzene ≤ 100mg/m³,

Acetonitrile ≤ 50mg/m³;

Non-methane total hydrocarbons:

          ---Removal rate ≥ 97%,

         ----Concentration of emission ≤ 120mg/m³;

Noise (1m from VRU): ≤ 85dB (A)

Height of exhaust port: ≥ 15m.