SCR Catalyst Cleaning Online Prevents Emergency Shutdown

Steam Methane Reformer (SMR) with Downstream SCR System

SMR Production rate was being reduced and the pressure drop across SCR (Selective Catalytic Reduction) catalyst was increasing due to surface fouling hindering gas flow. SCR Catalyst Cleaning helped to remove fouling and reinstate the efficiency.

Selective catalytic reduction (SCR) converts nitrogen oxides with the aid of a catalyst into diatomic nitrogen (N2), and water (H2O). A reductant, typically anhydrous ammonia (NH3), aqueous ammonia (NH4OH), or a urea (CO(NH2)2) solution, is added to a stream of flue or exhaust gas and is reacted onto a catalyst. As the reaction drives toward completion, nitrogen (N2), and carbon dioxide (CO2), in the case of urea use, are produced.

SCR Hot Vacuuming Service

The IGS Hot-tek team created access ports upstream of the SCR catalysts and performed a LanceScope inspection to identify fouling. SCR Catalyst cleaning was performed online without interruption to production, on time and budget without safety issues.

SCR Catalyst Fouling

SCR catalysts are made from various porous ceramic materials used as a support, such as titanium oxide, and active catalytic components are usually either oxides of base metals (such as vanadium, molybdenum and tungsten), zeolites, or various precious metals.

Due to draft blockage, the SMR suffered the insufficient process pre-heat and steam production, excess stack temperature. The Plant was in danger of needing an emergency shutdown to clean their catalysts.

Online SCR Cleaning

Hot-tek LanceScope inspection identified SCR Catalyst fouling. Cleaning of 200 SCR catalyst screens was then performed online without interruption to production.

SCR Catalyst Cleaning Results and Payback

Pressure drop across the catalysts was returned to within 5% of design. The plant recorded payback within less than a month. As a result of the cleaning, the SMR efficiency was improved, process pre-heat and steam production increased, stack temperature reduced, and draft improved.

Cleaning SCR Catalyst with Hot Vacuum Service


Fired Heater