The liquid air separation plant operates normally for about two years, and the fractionation tower system should be heated and thawed. Because the liquid air separation plant has been running for a long time, the low-temperature equipment and pipelines in the rectification system will be blocked due to the internal precipitation of ice or mechanical powder, resulting in an increase in the resistance of the fractionation tower. Therefore, it is necessary to warm and thaw the fractionator system to remove the precipitate.
Under normal circumstances, the heating and thawing operation is performed during normal shutdown: the liquid air separation plant must be drained after the normal shutdown. The dry air is introduced into the lower tower through the main heat exchanger, and all the liquid discharge valves of the lower tower are opened, so that the impurities accumulated in the main heat exchanger and the lower tower are heated and discharged out of the cold box after reheating. Open the liquid air throttling inlet valve V1 and the liquid nitrogen throttling inlet valve V3, introduce the heating gas into the upper tower, and open the upper tower blow-off valve according to the flow path for heating. Warming is complete when the inlet and outlet temperatures of the warmed gas are substantially the same.
DEAR Air Separation has long-term experience in the design, production and manufacture of liquid air separation plant, correctly analyzes the factors affecting the fractionation tower system, and makes corresponding theoretical guidelines for the operation, heating and thawing of the liquid air separation plant fractionation tower system.
