| 摘要 |
<p>PURPOSE:To reduce impurities by taking out N2 purified in a fractionating tower in a liquid state, removing CO with adsorption at a low temperature, collecting a part as liquid N2, making residual matter to heated gas, cooling to normal temperature in heat-exchange with raw material air and collecting N2 gas. CONSTITUTION:Raw material air is compressed by an air compressor 1 and moisture and CO2 are removed in an adsorbing tower 3 by adsorption through a CO/H2 remover 2. Next, resultant air is cooled to about -170 deg.C by air-heat exchange 4 or N2-heat exchange 5 and introduced into a fractionating tower 6. The air is separated by fractionation in the fractionating tower 6 and resultant liquefied air containing high-boiling point components such as CO2, hydrocarbon and moisture remained in a tower bottom part is gasified, then discharged into the atmosphere. Highly purified N2 gas fractionated in the fractionating tower 6 and risen is made to liquefied N2 in an N-condenser 7 to make a lowering solution in the fractionating tower 6. The aimed N2 to be product is taken out from an upper part of the fractionating tower 6 in a state of liquefied N2 and introduced into a low-temperature adsorbing tower 9 to remove CO to about several ppm. Thereafter, a part is taken out as highly purified liquefied N2 and the remain is introduced into a sub-condenser 10, then the whole amount is gasified, thus collected as highly purified N2 gas through a particle filter 11.</p> |
