MCF upgrades urea plant introducing MP Scrubber and Safurex® HP Stripper

Indian Mangalore Chemicals and Fertilizers Ltd. successfully commissioned a MP scrubber and a Safurex^® -made HP stripper in its urea plant in May 2006.

The MP scrubber is operated at 20 bar and replaces the HP scrubber that was operated at 140 bar. The equipment washes inert components that are present in the urea synthesis off-gas, using recycled carbamate solution from the LP section of the plant. This results in a MP carbamate solution that is recycled to the urea synthesis section without recycling more water and harming synthesis conversion. As in any other Stamicarbon CO₂-stripping plant, no separate ammonia recycle is needed. Simpler of design, a MP scrubber eliminates the need of a more complex and costlier HP scrubber. As such, a MP scrubber contributes to low investment for new urea plants too. As for intrinsic safety, accumulation of combustible components under HP conditions is intrinsically avoided.

The HP stripper is made of Safurex^®, a duplex stainless steel jointly developed by Sandvik and Stamicarbon and dedicated for use in urea plants. Highly resistant against corrosion and benefiting from superior strength, Safurex^® has earned wide acclaim in the past decade in urea plants around the world. Yet it is the first time this material is applied in India. Safurex^® withstands corrosion even in absence of oxygen that is usually dosed in urea plants to ensure passivation of steel, which means that the plant is operated intrinsically safer. Being a stronger material than conventionally used materials, less material is used, allowing for less weight and lower cost. Safurex^® is the most suitable material presently available for HP strippers, condensers and reactors in any urea plant.

Another feature of the HP stripper is that the level control relies on radar-based measurement, which is significantly user-friendlier and lower cost than the earlier used radioactivity-based measurement.

To improve safety to state of the art level, a hydrogen conversion system was installed in the discharge head of the CO₂-compressor. Hydrogen conversion is another feature underlining the care for safe design in modern Stamicarbon plants.

Mangalore Chemicals and Fertilizers operates a Stamicarbon Licensed urea process since 1977. In 2002, the capacity was increased from 1030 to 1290 mtpd.