Because nurseries with soil-bound crops like lettuce or cut flowers are getting bigger, a 'normal' steam boiler isn't enough anymore in a lot of cases. Steam of over a hundred degrees Celsius is necessary to decontaminate the soil.
When the distance from the steam boiler in the boiler room to the soil that needs to be decontaminated is too big, steam cools down, causing wet steam, which isn't good for the soil.
Reason for a Dutch chrysanthemum grower to purchase a gas fired steam heater to be able to steam the soil better and faster with 150 degree Celsius steam.
Van der Mark Ketelonderhoud installed one of those steam heaters from Thermeta at the chrysanthemum grower. "A steam boiler is like a small kettle, in which water isn't heated to steam, but steam is heated to overheated steam", tells Erwin van der Mark. "The heating is done by a small gas burner."
Less energy loss because of dry steam
The steam boiler makes it possible to bring low pressure steam to a very high temperature without the high pressure steam boiler that's usually used, they know at producer Thermeta. "On the job, growers often go for 150 degrees Celsius, although the exact temperature is dependent on the grower's wishes and the distance", says Egbert de Gelder. "At a temperature of 150 degrees Celsius the steam is completely dry, so it doesn't deposit water in the steam pipe, which lowers the energy loss."
Another advantage is that the steaming time can be cut short by about 20%. "Less fuel will be used on balance, because the shorter steaming time saves more energy than the steam heater needs extra."