Nitrogen-enriched gas preparation method, gas separation method and nitrogen-enriched gas preparation device

Abstract

Provided are a nitrogen-enriched gas production method and a nitrogen-enriched gas production device that reduce load variations of a compressor in order to fully exert the performance possessed by the compressor. The nitrogen-enriched gas preparation method is to use a plurality of adsorption tanks filled with adsorbents to separate the nitrogen-enriched gas from the raw material air containing nitrogen. process, decompression regeneration process and pressurization and equalization process. In the pressurization or decompression and equalization process, the raw air compressed by the compressor is stored in a branch set between the compressor and the In the compressed raw air tank between the adsorption tanks, and in the pressurized adsorption process, the compressed raw air stored in the compressed raw air tank is introduced into the adsorption tank as the pressurized raw air Part of the gas in the above-mentioned adsorption tank is used.

Description

technical field [0001] The invention relates to a nitrogen-enriched gas preparation method, a gas separation method and a nitrogen-enriched gas preparation device. this application claims priority based on Japanese Patent Application No. 2012-016575 for which it applied to Japan on January 30, 2012, and uses the content here. Background technique [0002] In general, nitrogen-enriched gas (hereinafter referred to as "nitrogen-enriched gas") separated and purified from feed air containing nitrogen (hereinafter referred to as "raw air") by pressure swing adsorption (PSA) ”) are used for various purposes such as explosion-proof purge gas and atmosphere gas for heat treatment furnaces. [0003] For the separation and purification of nitrogen-enriched gas by the PSA system, electricity is exclusively used as power, and in recent years, further power saving toward reduction of maintenance costs and energy saving has been expected. [0004] Conventionally, as a nitrogen-enriched ...

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Problems solved by technology

[0027] However, in such Figure 8 In the method of using the compressed raw air tank 107, the pressure in the first adsorption tank 103A or the second adsorption tank 103B before the pressurization and equalization process or the pressure reduction and equalization process is different from the maximum operating pressure of the raw air compressor 102 When similar (that is, when the pressure in the compressed raw air tank 107 is similar to the maximum operating pressure of the raw air compressor 102), it does not help the pressure rise protection during the pressure equalization process

[0028] In addition, by using the raw air compressor 102 with the no-load operation mechanism, it is possible to switch the raw air compressor 102 to the no-load operation during the pressure equalization process to prevent the pressure from rising. The problem that it takes time for the machine 102 to switch to load operation again

In addition, since the raw material air compressor 102 is switched to no-load operation, the pressure rise in the adsorption tank during the pressurized adsorption process becomes slow, and the performance as a compressor cannot be fully utilized. The increased volume of pressurization is equivalent to the amount of compressed raw air tank 107, so there is a problem that it is not conducive to the pressurization during the pressurized adsorption process and leads to a decrease in the performance of the PSA.

[0029] In addition, the method described in Patent Document 1 requires the use of an inverter control system in order to effectively utilize the raw air compressor 102, which has the problem of increasing costs.

[0030] In addition, even in the case of adopting such a control system, since the on-off valves 111a, 111b located on the upstream side of the first adsorption tank 103A and the second adsorption tank 103B are closed during the pressure equalization process, the operating pressure of the raw air compressor 102 is reduced. Rotating speed

As a result, the performance possessed by the compressor cannot be fully exerted, which leads to an increase in the required capacity of the raw air compressor 102 that should be selected, resulting in an increase in the size of the device, which is unsatisfactory from the viewpoint of power saving.

[0031] In this context, from the point of view of power saving, cost saving, and space saving, an operation method and device that can fully exert the performance possessed by the compressor is desired. Therefore, a method of reducing the load variation of the compressor is required, and further progress is made. The method of continuous operation, but the actual situation is that there is no practical and effective solution

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