Mercury Removal Unit (MRU) Design

About Mercury Removal

Mercury in natural gas causes severe corrosion of aluminum heat exchangers in cryogenic plants. Mercury removal units (MRU) use solid adsorbents to capture mercury before it can damage equipment.

Why Mercury Removal is Critical

• Aluminum Corrosion: Mercury amalgamates with aluminum
• Equipment Damage: Can cause catastrophic heat exchanger failure
• Costly Repairs: Replacement of brazed aluminum units very expensive
• Safety Risk: Leaks in cryogenic equipment are dangerous

Typical Performance

• Inlet Hg: 1-500 μg/Nm³
• Outlet Hg: <0.01 μg/Nm³
• Bed Life: 6-24 months typical
• Adsorbent Capacity: 10-20 wt% Hg

Design Considerations

• Always use at least 2 beds in series (lead/lag)
• Monitor outlet mercury concentration regularly
• Change out lead bed when breakthrough occurs
• Proper disposal of spent adsorbent required
• H₂S and water can reduce adsorbent effectiveness