Hot start method for boost expander

Abstract

The invention relates to the field of refrigeration process of boost expanders, in particular to a hot start method for a boost expander, wherein the method is characterized in that in a hot start initial stage, all gases exhausted from an expansion end enter a waste nitrogen channel of a main heat exchanger to bypass and quicken decrease of temperature of the main heat exchanger, simultaneously, air exhausted from a cold end of the main heat exchanger flows into the expansion end at the first, then air in the middle of the main heat exchanger gradually flows into the expansion end after the temperature of the air exhausted from the expansion end is reduced to a designed value to enable the expander to run at the highest secure rotation speed all the time, and to fully develop maximum refrigerating capacity to shorten space division hot start time. Compared with the prior art, beneficial effects of the method are as follows: after the method is utilized, hot start time of the expander is shortened from former 48 h to 42 h, a bypass operation period is crossed fast in relatively shorter time, and refrigerating capacity of the expander is fully developed to further reduce power consumption for start.

Description

technical field [0001] The invention relates to the refrigeration process field of a booster expander, in particular to a method for thermally starting a booster expander. Background technique [0002] At present, in the refrigeration process using a booster expander, the compressed air is purified by molecular sieves, and one way enters the lower tower through the channel A of the main heat exchanger; Channel B of the main heat exchanger enters the expansion end from the middle part and the cold end of the main heat exchanger to cool down, and then enters the upper tower. [0003] When the above-mentioned air separation equipment is hot started, because the temperature of the middle part of the main heat exchanger and the outlet of the cold end is gradually reduced, the air temperature at the inlet and expansion end is higher than the normal working condition for a long time at the initial stage of start-up, and the booster end is at the same time for a long time. In the b...

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Problems solved by technology

[0003] When the above-mentioned air separation equipment is hot started, because the temperature of the middle part of the main heat exchanger and the outlet of the cold end is gradually reduced, the air temperature at the inlet and expansion end is higher than the normal working condition for a long time at the initial stage of start-up, and the booster end is at the same time for a long time. In the bypass operation state, the cooling efficiency is greatly reduced. Generally, the hot start process takes about 48 hours, and the power consumption is huge.

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