Summary
Yara Sluiskil B.V. is a subsidiary of the Norwegian “Yara International ASA” group. In addition to basic products such as ammonia, nitric acid and urea, the company also produces end products such as fertilisers and Air1® (a product that is injected in the catalysts of trucks). Raw materials are air (nitrogen) and energy (natural gas).
Evides Industriewater has been supplying process water to Yara from its production plant in Sint Jansteen for years now. Until recently, Yara used to turn this into industrial water itself. As Yara’s demineralisation plants needed replacing and did not have enough capacity to meet the future demand for demineralised water, Evides and Yara started discussing the possibilities of collaboration in 2006. This led to a 12-year DBFO agreement for the supply of 375 m3/h. The construction of a demineralisation plant and condensate polishing plant forms part of the contract. Evides designed, engineered, financed and constructed the plants under its own management. The new plant produces more than 3 million m3 of demineralised water on an annual basis; Evides produces another 2 million m3 of demineralised water through condensate polishing.
Biesbosch water turns into demineralised water
As Yara needs more demineralised water in the future than can be produced at the Sint Jansteen production site they needed to introduce a second raw material: water from the Biesbosch. Supply reliability has considerably increased as a result, which is undoubtedly valuable for an industrial complex such as Yara Sluiskil.
For Yara, quality is more than just a precondition. Demineralised water is not only used as boiler feed water, it is also added to Air1®. The conductivity of the water supplied is therefore subject to a maximum of 0.2µ S/cm. In normal processing conditions, the maximum usually stands at 0.06 µ S/cm. A special element is the TOC content (100 ppb), in combination with the use of surface water as a raw material.
Project details
In order to be able to supply the requested demineralised water capacity of 3 million m3/year (375 m3/h) the plant has four lines of 125 m3/h each. Two of them (the lines that use Sint Jansteen water as raw material) are based on a classic IEX design (cation, degasser, anion, mixing bed), while the other two lines (those fed with Biesbosch water) are based on an innovative IEX design (cation, degasser, adsorption filter, anion and mixing bed). As such, the plant has a redundancy of N-1, which means that one line is always operational as backup.
Evides has also constructed two condensate polishing lines (one of which serves as a backup) with an overall capacity of 2 million m3/year.