During the bulb storage season from August through November 2024, Agrozone and Vertify conducted additional research on ethylene oxidation by ozone in bulb storage cells at Vertify's location in Zwaagdijk east.

‍

Ethylene is a harmful gas released during the storage of tulip bulbs. Normally, this ethylene is removed by intensive ventilation of the heated storage cell. A lot of energy is lost in this process.

‍

The purpose of the study was to investigate in a practical situation whether the ethylene concentration in the storage cell could be kept below the damage threshold of 100 ppb by oxidation with ozone, in a situation with no or minimal ventilation.

‍

For the study, boxes of tulip bulbs were placed in a regular storage cell. Ozone was introduced into the cell via a Multisplit® installation. The ozone concentration was measured continuously and the dosage was adjusted accordingly. The ethylene concentration was also measured continuously and tested against the damage threshold.

‍

The study showed that the concentration of ethylene could be kept well below the damage threshold of 100 ppb by oxidation with ozone throughout the storage season. This involved no or minimal ventilation. When the ozone installation was temporarily switched off (stop tests), ethylene soon exceeded the threshold again. Ozone oxidation was then restarted in each case.

‍

The research shows that ozone oxidation of ethylene can be a good alternative to intensive ventilation during bulb storage. This opens perspectives for storage concepts with no or minimal ventilation and minimal energy loss.

‍

Some of the bulbs from the ozone oxidation cell were planted in late November 2024. Another part of the bulbs is reserved for forcing. From assessment of product quality, the effect of ethylene oxidation process on the crop will be determined.

‍

‍