DEAR Biogas purification unit.The backflow cryogenic gas is composed of several gases which have been separated into product oxygen, product nitrogen and waste nitrogen. When calculating the heat exchange incomplete loss, the total heat exchange incomplete loss should be calculated separately and then added up. Because of the largest amount of polluted nitrogen, the temperature difference at the hot end has the greatest influence on the incomplete heat exchange loss.DEAR Biogas purification unit.At the beginning of heating, it is necessary to turn down the oxygen and nitrogen vent valves, limit the discharge volume, increase the low pressure pressure, increase the gas volume of the pipeline with large resistance, and speed up the heating thoroughly. When the fractionator is heated, the molecular sieve purifier also needs to be heated. If the low pressure is too low, the regeneration of purifier will be affected. But the pressure should not exceed the normal working pressure to ensure safety.
DEAR Biogas purification unit.The oxygen content in blast is increased by 1%, the pig iron production is increased by 3%, and the coal injection per ton of iron can be increased by 13 kg. At present, the oxygen content is generally 23% - 25%, and the highest is 27%. The blast volume of blast furnace is very large, and 12000m3 air is needed for each ton of iron. Although the oxygen enrichment degree is not high, the oxygen consumption is also quite large. The oxygen content is increased by 1%, and about 16-18m3 / T oxygen is needed for each ton of iron.When the absolute pressure is 0.57mpa, the nitrogen purity increases from 98% to 99.9%, and the condensation temperature decreases from 96.1k to 95.9k. When the purity of nitrogen is constant, the condensation temperature increases with the increase of pressure. For example, when the nitrogen purity is 99.9%, the absolute pressure increases from 0.57mpa to 0.6MPa, and the condensation temperature increases from 95.9k to 96.6k.The stage cooling method is one of the start-up operation force methods of air separation plant which uses switching heat exchanger to remove water and carbon dioxide. In the full low pressure air separation unit, the moisture has been basically frozen at - 40 ～ - 60 ℃ under the operating pressure of 0.5MPa (gauge pressure). However, carbon dioxide begins to precipitate and freeze below - 133 ℃ until the end of freezing at - 165 ～ - 170 ℃.
The temperature drop of air from 0.6MPa throttling to 0.1MPa is only about 1 ℃, while the temperature drop can reach 80 ~ 90 ℃ theoretically through expansion of expander, and the effect of temperature drop is much better than that of throttling. The reason is that the throttling process does not output work, and the decrease of temperature is caused by the increase of molecular potential energy.The position of oxygen generator explosion is related to the type of air separation unit to some extent. In the process of high, medium and double pressure, the possibility of explosion is relatively high; in the device of producing liquid oxygen, the main cooling has not been exploded, while the main cooling of gas oxygen device is the central part of explosion. The degree of explosion damage is related to the explosion force, and the weak explosion may only damage individual pipes, even not be detected by the operator.DEAR Biogas purification unit.Pearlite has good fluidity, and its density is lower than that of water. If people fall into the pearlite layer, they will be drowned and suffocated. Therefore, the manhole on the top of the cold box and the loading position should all be installed with a square grid shaped safety iron grid welded with 8-10mm steel bars to prevent accidents.
Helium is very inert. When smelting special rare metals such as titanium, zirconium and semiconductors such as silicon and germanium, helium should be used as protective gas. The welding and cutting of high melting point and thick alloy also need helium protection. Helium has strong diffusivity and permeability. Therefore, helium is the best leak indicator for pressure vessels and vacuum systems with strict requirements.DEAR Biogas purification unit.Before the liquid appears in the start-up stage of the air separation unit, the lowest temperature is generated by the expander, and the temperature in the distillation column can not be lower than the temperature after expansion. However, liquid appears in the lower tower, and when the saturated liquid throttles to the upper tower, the pressure decreases, part of it gasifies, and the temperature also decreases to the saturation temperature corresponding to the upper tower pressure. For example, when the liquid nitrogen at - 177 ℃ on the top of the lower tower is throttled to the upper tower, the temperature can be reduced to - 193 ℃.
