Absorption Technology Voc Treatment System For Low Medium Concentration Vapor Recovery

Absorption Technology Voc Treatment System For Low Medium Concentration Vapor Recovery

Absorption Technology for Vapor Recovery Unit

1. 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 Absorption Process is suitable for treatment of low & medium concentration oil vapor. As long as proper absorbent is available at site, absorption process is recommended owing to the easy operation and reduced investment.

Though usually applied in combination with other process, the absorption process can also be solely applied for treatment of substances easily soluble in water, acidic or alkaline liquid. For instance, it can use water to handle waste gas containing methanol, acetic acid, ammonia, acetone, etc. to make it acceptable for the emission standard.

1. Principle / Flow Procedure

Taking advantage of different solubility of different compositions, The Absorption Process can separate those easily soluble compositions from others. Most light hydrocarbons dissolve into the absorbent and waste gas containing little light hydrocarbons is discharged from the top of the tower. For different types of oil vapor, the absorbents can be water, acidic aqueous solution, alkaline aqueous solution, gasoline, diesel and heavy hydrocarbon, etc. More explanation about the process will be given taking methanol recovery with water absorption technology for example.

The oil vapor after flame arrester is pressurized by an induced fan and then delivered into the absorption tower, where it contacts the absorbent liquid (water) flowing in opposite direction for vapor-liquid equilibrium. Acceptable emission is obtained after multi-stage equilibrium and discharged from the top, while the liquid with rich methanol leaves from the bottom.

1. Structure & Parameter (typical project)

1. Advantage

1. Software: ASPEN for process calculation, SW6 for equipment calculation, CADworx for design of the skid;
2. High efficiency structured packing and low consumption of absorbent;
3. High recovery efficiency and acceptable emission from tower top;
4. Delivered as a skid to reduce site installation work;
5. Fully sealed blower and flanged connection in the skid to achieve zero leakage;

6) ExdIIBT4 or ExdIICT4 explosion proof.

1. Applied data for an typical project

PROJECT PICTURE

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;

Acetone ≤ 100mg/m³,

Phenol ≤ 20mg/m³,

Methanol ≤ 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.