Temperature is an important factor to control the penetration rate of citronella oil
. Increasing the steam pressure will increase the steam temperature accordingly, which can accelerate the distillation speed and shorten the distillation time. According to the test, when the top pressure of steamer is 1kg / cm2, the oil yield and aldehyde content of small steam distillation processing plants with boiler volume of 2.5m3 and steam pressure of 3.5kg/cm2 are 0.06% higher and 0.05% higher than those of 1.3kg/cm2. Therefore, the top pressure of 1 kg / cm 2 is suitable for safe production. Whether water distillation or steam distillation, it is necessary to keep the gas pressure stable, and the oil production rate will be reduced when the air pressure changes from high to low. Therefore, the fire power of water distillation should be always fierce, and only large but not small. In steam distillation, the inlet steam should be from small to large, so that the steam pressure rises steadily.
That is to say, the high temperature oil-water mixture steam becomes the low-temperature oil-water mixture by the cooling effect of the condenser tube. The condensed oil-water mixture should be at 30-35 ℃. If it is above 60 ℃, the oil will be partially volatilized, especially vanillin. The condensate pipe should be placed in the center of the ditch, and the flow direction of the mixture is opposite to that of the cooling water. At the same time, the condensate pipe should not be buried in the mud of the ditch, and heat dissipation should be used. Otherwise, the temperature of the mixture will generally be 5-10 ℃. The condensate from the condenser tube must enter the oil-water separator to separate citronella oil and water.