Novel external pressurized and internal liquefied pure nitrogen preparation device

Abstract

The invention discloses a novel external pressurized and internal liquefied pure nitrogen preparation device which comprises a filter, a turbine air compressor, an air pre-cooling unit, alternatively-used molecular sieve adsorbers, an electric heater, a main heat exchanger, a supercharging expansion machine, a rectification column I, a rectification column II, a condensing evaporator I, a condensing evaporator II, a subcooler, a liquefier and a supercharger. The invention also discloses a novel external pressurized and internal liquefied pure nitrogen preparation method. According to the device and method, sewage nitrogen reflux expansion refrigeration is adopted, the pressure utilization efficiency is high, and the energy consumption of the device is low; double tower parallel nitrogen production is adopted, the upper tower pressure can be higher or lower than the lower tower pressure, and two nitrogen products with the same pressure level or different pressure levels can be preparedsimultaneously, and some liquid nitrogen products can be prepared; and an internal liquefier and an external supercharger are arranged, the external supercharger is located outside a cold box, maintenance and overhaul are facilitated, the internal liquefier is located inside the cold box, the cold loss is small, meanwhile, the selected type of the external supercharger is not limited, and therefore the application range of the device and the method can be greatly increased.

Description

technical field [0001] The invention relates to the technical field of air separation, in particular to a novel external pressurized internal liquefied pure nitrogen production device and method. Background technique [0002] With the technological development and innovation of chemical industry, electronics, new materials, porcelain steel industry, glass and other industries, the demand for nitrogen has increased rapidly, and at the same time, higher requirements have been put forward for the purity of nitrogen. [0003] There are currently two types of pure nitrogen equipment commonly used in the market: single-tower nitrogen production and double-tower nitrogen production. The single-tower nitrogen production is smooth and can produce a certain pressure of product nitrogen for direct use by users. Although this type of process has a simple structure, the extraction rate of the device is low, and the unit consumption of the product is high, which is not suitable for the de...

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Problems solved by technology

The single-tower nitrogen production is smooth and can produce a certain pressure of product nitrogen for direct use by users. Although this type of process has a simple structure, the extraction rate of the device is low, and the unit consumption of the product is high, which is not suitable for the demand for large-scale nitrogen consumption; the double-tower Nitrogen production is divided into atmospheric nitrogen and pressurized nitrogen processes. The atmospheric nitrogen process can produce atmospheric nitrogen or low-pressure nitrogen with a pressure of 0.1-0.2MpaG. The extraction rate of the device is high, and the energy consumption is lower than that of single-tower nitrogen production. Due to the low pressure of the product, the product nitrogen needs to be compressed by a nitrogen compressor to meet the user's requirements for nitrogen pressure. The nitrogen process with pressure is generally a process with a liquid nitrogen pump. For nitrogen volume 3 / h air separation unit, it is difficult to choose a liquid nitrogen pump, and because the liquid nitrogen pump is generally placed inside the cold box, once the liquid nitrogen pump fails, the cold box must be sanded, so the configuration of the liquid nitrogen pump generally chooses imported liquid Pumps, one for the other

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