Kilbush Nurseries CHP plant

CO2 as a nutrient

In order for the CHP unit to work at its optimum, Edina and Kilbush Nurseries appointed Steuler who have patented the leading CO₂ Recovery System, the ECO₂ Pro system for greenhouse applications.

The exhaust gases of gas engines having a capacity of up to 2MW approx. and being installed in greenhouses to produce power and heat, are cleaned by the Steuler catalyst system in two stages. This happens in such a way that the necessary requirements of the plant and operational procedures of the nursery are met. Thus, the nitrogen oxides are reduced by 95% by adding a 40% urea solution into the exhaust gas stream in connection with a SCR catalyst.

In a second stage, the so-called oxidation stage, Ethene is reduced by 99%. Carbon monoxide (CO) is reduced, with an emission of <1 ppm of detection limit.

One of the greatest advantages is the use of CO₂ from the exhaust, ambient levels of CO₂ are around 300 parts per million (ppm) but significant improvements to the crops have been observed when levels are increased to around 1,000 ppm which is achieved from the CHP process. This remains a safe operational level and is closely monitored.

Raising CO₂ to these levels has shown an increase of up to 50% in photosynthesis given appropriate light levels, leading to an approximate 30% gain in plant size. This results in earlier, more prolific flowering, higher fruit yield, increased plant growth and vigour, in short, “growers should regard CO₂ as a nutrient”.