Pumping Urea

Urea is a naturally occurring compound, manufactured on an industrial scale and is one of the largest chemicals produced in terms of quantity. Urea is extremely useful for its nitrogen content.

Applications

  • A large proportion of Urea is sent to the fertilizer industry where it is used to produce solid and aqueous formats of urea compounds. These are then applied to soil and crops as a rich source of ammonia which is then used for nitrification in plant growth.
  • In the production of resins, urea is an activating agent with formaldehyde to assist in the setting of the plastics to form shapes such as all-plastic products and when it is used as a bonding agent in plywood.
  • Urea is also used to create urea nitrate, a compound useful in explosives.
  • An emerging use for urea is as a component part of automobile exhaust systems where it acts as a scrubbing solution to clean harmful nitric oxide and other related gas compounds. 
  • There are many other uses for urea including food and beverage, aquatic/environmental and in toiletry products.

Pumping considerations

Urea liquor or aqueous urea is an irritant to the skin and eyes and where vapourised, to the respiratory system as well. The liquor ranges between 40-70% for commercial applications with an S.G. of 1.14 to 1.17. Formaldehyde blends can be much higher at 1.3 and above with a viscosity between 250-600 cPs.

Urea compounds such as formaldehyde-based can be toxic to skin and the respiratory system. It is strongly recommended that a mag drive centrifugal pump is installed to handle this solution due to the danger posed to the workforce should a leak occur with a shaft-sealed pump. Shaft-sealed pumps carry the inherent risk of failing as the sealing system will suffer abrasive wear as the shaft mechanism is working. An o-ring sealing system provides a guaranteed leak-free method of transferring a liquid. 

Depending on the exact urea solution, a non-metallic pump is recommended such as an ETFE or PP encapsulated cast iron construction with PTFE, kynar or viton elastomers. 

Note the impeller may require trimming for higher concentrations and for viscous mixtures such as urea-formaldehyde solution.