Huntsman Holland, the chemicals business which produces raw materials for the polyurethanes industry, has successfully worked with global pump specialist DESMI.
The major chemical chain started in the 1960s as ICI in the Botlek area of the Netherlands and now has five facilities, spread over an area of 180 hectares, working with raw materials for the polyurethanes industry. In this production process, substances such as sorbitol, amines and sucrose are used to make polyols. MDI is made with another process. The company's products, and semi-finished products, are used in the insulation market, the automotive industry, the adhesive industry and as raw material for footwear, furniture, and a variety of plastics.
Within the five facilities there are pumps for the transport of the various raw materials. Previously pumps with mechanical seals were used, but which in practice were problematic, says mechanical maintenance engineer, René van de Vlugt. “In this case, when these pumps exhibit leakage, it is not a particularly big problem for the environment and man. The spilled material hardens immediately when it comes in contact with the atmosphere, especially if it is wet, and will not spread in the area. However, this hardening creates relatively much work for the maintenance department. The material must literally be chipped away and then the pump and the surroundings must be cleaned. Then, of course, the leak must be fixed. In short: the maintenance costs of these pumps were too high. For this reason it was decided to employ a ‘zero-drip’ policy, in which we don’t tolerate any leakage.”
A solution for this problem was found in magnetically coupled pumps from the ROTAN ED Series supplied by DESMI. One of the properties of these pumps is that the pumped medium in the system is hermetically sealed by the application of a magnetic coupling. As a result, it does not require a shaft and mechanical seal to be applied, which may allow gaseous exchange between the medium and the atmosphere. The quantity of magnets is dependent upon the capacity to be transferred. They are made of rare earth materials, which are magnetised up to ten times more than iron. There the choice is from neodymium - iron - boron magnets for operating temperatures up to 150°C, or samarium cobalt for higher temperatures.
“The reason we contacted DESMI was that we already had a number of ROTAN pumps and we were generally satisfied with them.” said Mr Van der Vlugt.
“In fact, the first pumps which we purchased in 2004, still operate without problems. Based on this experience, it was decided to replace all pumps in the process concerned with a mechanical seal by a magnetically coupled construction.''