COG Hydrogen Production: Defoaming Strategies from Desulfurization to PSA

Instrument failures can occur at multiple stages of coke oven gas (COG) hydrogen production:

Compression Stage: Emulsified heavy tar components cause foam, distorting oil separator level gauges

Desulfurization Stage: Foaming in desulfurization solution triggers erratic differential pressure transmitter data

PSA Stage: Foam from trace lubricants leads to pressure sensor drift in adsorption towers

A Hebei hydrogen project (annual output: 80 million m3) experienced 25+ monthly malfunctions of PSA control valves. Investigation revealed foam residues from upstream processes reduced CO analyzer sensitivity, causing sequence errors.

Full-Process Defoaming Strategy

Implement targeted defoamer dosing at key points:

Post-Compression Cooler Inlet: Add CT-Gas610 oil-soluble defoamer (0.005%) to break tar emulsion foam

Desulfurization Circulation Pump Inlet: Inject CT-Gas820 alkali-resistant defoamer (0.02%) to stabilize regeneration tank levels

Pre-PSA Oil Remover: Dose CT-Gas760 low-volatility defoamer (0.001%) to protect adsorbents and instruments

Quantified Benefits

After full-process implementation at a Liaoning plant:

PSA valve failures decreased by 80%, extending adsorption tower service life to 4 years

Compressor lubricant consumption reduced by 35%

Instrument calibration frequency reduced from weekly to monthly, cutting annual maintenance costs by ￥1.2 million

Critical control: Install online foam sensors after freeze separators to trigger automatic dosing when foam tendency exceeds 45%. Regularly clean coalescer filters to prevent defoamer residue buildup. Chemi Tech provides process audit services to customize defoamer formulations for varying tar content (200-5000mg/m3) in gas feeds.