Effect of Nitrogen Flow Rate on the Concentration of Nitrogen in Controlled-atmosphere Warehouse

Abstract

The decay and holding time of nitrogen concentration was characterized in a controlled-atmosphere warehouse with half life of pressure of 165 s. The relationship of nitrogen concentration, nitrogen holding timeand grain temperature was further studied. The results showed that, the nitrogen concentration gradually decreases with the time, when the nitrogen concentration in the controlled-atmosphere warehouse reached to the target concentration of 98.0%. The concentration of nitrogen was related to nitrogen leakage and sorption.An increase of the nitrogen concentration required that the amount of supplemental nitrogen is greater than the amount of leakage. When there is no nitrogen supplement in the controlled-atmosphere warehouse, the monthly decrease of nitrogen concentration is 1.6%; when the monthly nitrogen supplement is greater than 12.4% of the grain warehouse volume, the nitrogen concentration will increase by 0.1% ～ 0.9%; the monthly nitrogen supplement is greater than 27.0% of the grain warehouse volume, the nitrogen concentration will greater than 1.0%. In addition, the amount of nitrogen supplementation has no direct effect on the temperature of the grain.

Keywords

• controlled-atmosphere warehouse
• nitrogen concentration
• controlled atmosphere
• grain
• cost analysis