Liquid nitrogen generator

Liquid nitrogen generatorThe nitrogen gas is compressed using a compressor and stored in a gas storage tank for future use. The compressor mainly consists of a compressor, a gas storage tank, a filter, a dryer, etc. After compression, the compressed air enters a refrigerated dryer for cooling and dehydration. After passing through a filter for oil and dust removal, it enters an adsorption tower containing carbon molecular sieves to selectively adsorb impurities such as oxygen and carbon dioxide, producing high-purity nitrogen gas.

When mixed gases in the air source pass through hollow fiber membranes, the differences in solubility and diffusion coefficient result in varying permeation rates of different gases in the membrane. The nitrogen permeation rate is relatively slow, which leads to retention in the membrane and achieves separation and purification. This instrument utilizes the difference in adsorption capacity between nitrogen and other gas molecules in molecular sieves to accumulate concentration differences, producing high-purity nitrogen at the end of the molecular sieve column. Simultaneously utilizing two molecular sieve columns, one adsorbs while extracting a portion of the product gas for analysis by the other, achieving online regeneration of the molecular sieve. The overall performance is that the instrument continuously outputs high-purity nitrogen gas.

　　Liquid nitrogen generatorPure nitrogen gas is produced by combining electrochemical separation and physical adsorption methods. The constant potential electrolysis method is used, and a microporous membrane is used as the separator between the two electrodes. The porous gas diffusion type oxygen electrode is used as the cathode, and the nickel mesh is used as the anode. The electrode installation adopts a hard support structure. This generator can operate stably under the pressure difference of the nitrogen chamber, avoiding cathodic hydrogen evolution and ensuring the purity of nitrogen gas produced.

The specific method for producing nitrogen gas is to use air as the raw material to send the gas into an electrolytic cell with electrolyte, and apply a direct current with a voltage of ≤ 1.5V between the two electrodes. At this time, oxygen is absorbed in the air inside the cell to obtain nitrogen gas. The electrolyte adopts a "forced circulation method", driven by an electromagnetic pump to circulate in the liquid circuit, which improves the electrolysis efficiency. The purity and flow rate of nitrogen can be adjusted, and 99.999% nitrogen products can be produced. The flow rate can range from several hundred milliliters to tens of liters to several cubic meters per minute. The purity size can be flexibly configured and customized according to each requirement, suitable for various gas chromatography detectors.

This method can produce high-purity nitrogen gas, but there are several minor drawbacks: it requires a high concentration potassium hydroxide solution as the electrolyte, which comes into direct contact with the gas and has the potential to affect the quality of the gas, as well as the possibility of being output along the gas path; High unit cost, not suitable for large flow generators; The reaction process only removes oxygen from the air and does not involve other impurity gases. Moreover, the reaction process requires high technical requirements for the production of electrolytic cells, and inappropriate electrolytic cell production techniques can cause a decrease in the purity of nitrogen gas by an order of magnitude. However, as a high flow nitrogen source, the nitrogen generator has a low total cost and is a low-cost solution.