Urea is playing a major role in reducing oxides of nitrogen pollution from heavy Goods Vehicles across Europe through its use in Selective Catalytic Reduction (SCR) systems.
The requirement to blend solid materials into a corrosive solution characterises the production of urea solution for the automotive market. Large volume production of the urea solution necessitates the use of corrosion resistant mixing and storage vessels.
Benefits of scale encourage the use of mixing batches of more than 100m3 which if conventional agitator technology was employed on mixing vessels would require major steelwork support and a large agitator and gearbox with their associated capital and maintenance costs.
Chem Resist have provided blending vessels up to 130m3 for this application using internally mounted all thermoplastic mixing eductor technology powered by a base mounted centrifugal pump eliminating the need for a large agitator and gearbox.
The blend normally comprises solid Urea prills delivered in one tonne bags and demineralised water presenting a solids handling challenge to the normal aqueous blending process. This is overcome by traditional spiral and bucket conveyor systems delivering prills to the top of the mixing tank and the mixing eductor technology ensuring dissolution of the prills into the concentrating solution.
A solid state densitometer records increasing density and manual refractive index measurements confirm compliance of the final solution with ISO 22241. The dissolution is aided by increasing water temperature and this facility can be provided as part of the packaged plant.
A matching storage vessel, pump and pipework allows transfer of the compliant solution and frees the blending vessel to resume production.
The plant is centrally controlled by a Siemens PLC with auto and manual modes of operation.The batch plant can be successfully manned by one operator with fork lift driving skills.
Our package can include full delivery and installation of the equipment and always provides a commissioning engineer who will complete wet and process commissioning and will train operators on-site.
This all thermoplastic Chem Resist blending plant has benefits as follows :-
• Reduced capital cost and footprint
• Eliminates internal and external corrosion of the blending vessel
• Low power blending technology
• No metallic contamination of the final solution
• Turnkey capability of design, manufacture, installation and commissioning