Description
3.1 Process
Brief
l The
whole air separation plant is according to the different boiling
points of air components, by pressurized, cooling, removed H2O and
CO2 by molecular sieve, cooled to the liquid temperature in the
main heat exchanger, entered in distillation column, got oxygen and
nitrogen products.
l The
Air Separation Unit is of the process of air purification by
molecular sieves, refrigeration by a booster expander, separation
of the process air by rectification at low temperature and argon
production by argon columns.
l The
process air is fed into the air turbo compressor and compressed
to～1.1Mpa（A）, then fed into the air
pre-cooling system. After it is reduced to ***0℃, it is fed into
the alternative molecular sieve absorber vessels, where water
vapor, CO2 and dangerous hydrocarbons of it are removed by
molecular sieves.
l The
purified air mixed to the expanded air, compressed by
medium-pressure air compressor into two units : one direct access
to the main heat exchanger cooled to ~**8K, then drawn from the
central of heat exchanger, into the high-temperature expander.
After expanding gas flow back to the main heat exchanger, after
reheating out cold boxes into air booster. Another stream of air
boosted and cooled by the high-temperature expander, then boosted
and cooled by the low-temperature expander, then enter the cold
box, cooling to ~**0K in the main heat exchanger, a small portion
of air continued cooling, out heat exchanger and after restriction
entering the bottom of the lower tower, the majority of the
remaining air into the low-temperature expander. After the
expansion, the air divided into two units, one entering the bottom
of the lower tower, the remaining gas enters the main heat
exchanger, reheated out the cold box into air booster. Obtained
waste nitrogen from the top of upper tower, after sub-cooler,
reheated in main heat exchanger, out of cold box, then entered the
electric heater as MS regeneration gas, and the surplus part get
into the water tower.
