GEA DeMerc: Removal of mercury

Removal of mercury from process and exhaust gas in the Non-Ferrous metal industry is crucial due to mercury's toxicity, volatility and persistence in the environment.

Mercury removal is a three-stage process.

Gas Cleaning in Non-Ferrous metal industry consists of several process steps. First step in process gas treatment is particle removal by an ESP which includes particle-bound mercury. The second step takes place in the washing and cooling system, typically using calomel to remove large amounts of mercury. However, minimization of clean gas concentrations of mercury is limited by this process. This reduces quality and thus selling price of downstream produced sulfuric acid.

 

With the new third stage, GEA DeMerc, mercury contained in the gas downstream washing and cooling stage is adsorbed over a fixed bed consisting of new sorbent, which ensures fine Hg purification and thus improved sulfuric acid quality. Mercury clean gas concentration ≤ 25 µg/m³ can be achieved, regardless of the present mercury species (elemental or ionically bound) The usual abatement rate is ≥ 90 % over the runtime and mercury is finally bound as mercuric sulfide which is significantly less toxic than other mercury compounds.

 

Advantages of adsorption-based mercury removal

1. High Efficiency:

• Capable of removing >90% of mercury with clean gas concentration ≤ 25 µg/m³

2. Specific abatement:

• No interaction with valuable substance sulfur dioxide (neither adsorption nor conversion to H₂S)

3. Operational simplicity:

• Adsorption systems are relatively easy to operate and integrate into existing flue gas treatment setups.

4. Cost-Effectiveness:

• Sorbent is typically more affordable than activated carbon or noble metals.

5. Scalability and Flexibility:

• Modular design allows for easy scaling and retrofitting in existing plants.

6. Capacity and lifetime:

• GEA DeMerc will be adapted to customer needs and process conditions to have a maximum predictable lifetime.