Variable pressure absorption oxygen and nitrogen combined separation method and device

Abstract

The invention belongs to the technical field of mixed gas separation, in particular to a variable pressure absorption oxygen and nitrogen combined separation method and a pressure absorption oxygen and nitrogen combined separation device. The device comprises at least two absorption towers filled with absorbent, pipelines for supplying raw material gas to the absorption towers, pipelines for taking product gas from the absorption towers respectively, pipelines for gas component and energy recovery and exchange between the absorption towers and gas kinetic energy transmission from an absorption tower reaching absorption saturation to another absorption tower, and an oxygen and nitrogen product gas buffering tank, wherein an oxygen product gas is connected to the cleaning pipeline and control valve of the feeding end of each absorption tower, and the nitrogen gas product is connected to the cleaning pipe line and the control valve of the discharge end of each absorption tower. In the separation method provided by the invention, two high-purity products, namely oxygen and nitrogen, can be obtained at the same time through a single absorption and separation process, and the oxygen meets the requirements of aerially breathable oxygen. The device can be highly integrated, and the volume and weight of the device are in accordance with the development direction of aerospace on-board oxygen and nitrogen extraction and the requirements of on-board equipment.

Description

technical field [0001] The invention belongs to the technical field of mixed gas separation, and in particular relates to a method and device for separating raw gas mixtures through a non-cryogenic process, in particular to a separation system using a pressure swing adsorption separation system from a mixture containing various gas components. A method and device for recovering at least one product gas, more typically, a separation method and device for simultaneously separating oxygen and nitrogen from air. Background technique [0002] Oxygen and nitrogen are used as basic industrial gases with more and more important applications. In the fields of aviation and aerospace, oxygen is mainly used for breathing and combustion, personnel breathing at high altitudes, personnel breathing under nuclear and biological conditions, and high-altitude emergency parachuting Oxygen for breathing, oxygen-enriched or pure oxygen for combustion of aircraft, oxygen for emergency ignition, et...

AI Technical Summary

Problems solved by technology

However, because the system simply uses a single-stage system, the separation is not only limited by the separation selectivity of the adsorbent used, but also uses an unimproved process for this single pressure swing adsorption system, which makes it difficult to achieve high-purity gas groups. For example, it is difficult to achieve a high-purity product stream of more than 99% for oxygen, and it is difficult to achieve a high-purity product stream of more than 99.999% for nitrogen; in addition, the system has not considered recovery or thorough and effective recovery of each pressure swing adsorption system The valuable waste gas components that are excluded and the kinetic energy formed by compression, therefore, the recovery rate of the separate separation system must be low, and it is difficult to use industrially

[0013] Regarding multi-stage membrane separation, U.S. Patent US626559 discloses a method and system for separating a pure component gas from a gaseous mixture, using at least three stages In the separation system constructed by the membrane, the necessary compression equipment is omitted in a certain stage, thereby reducing energy consumption, and the commercialized oxygen and nitrogen separation membrane is used to improve the purification process of the mixed gas with less energy consumption and lower cost. The purity of at least one component of the product output as a product, however, as in the case above, it is difficult to achieve multiple product recovery of high-purity gases

[0014] Chinese patents CN 101376493A, CN 101412501A novel airborne oxygen / nitrogen production coupling system, a novel airborne oxygen / nitrogen production coupling system with a compression pump, disclose a dual-product stream separation system applied to airborne environmental conditions, It is mainly composed of molecular sieve pressure swing adsorption oxygen production system, hollow fiber membrane separation nitrogen production system and other accessories. The exhaust gas of the nitrogen production system is recovered, and dual-product gases: oxygen and nitrogen can be produced at the same time. This system can effectively reduce the demand for engine bleed air, and has a simple structure, no moving parts, reliable operation, small size and light weight , but obviously, it is difficult to produce oxygen with a purity of 99.5% that meets the requirements of the national military standard, and it is even more difficult to produce high-purity nitrogen with a purity of more than 99.99%.

[0015] Chinese patent CN 1798687A discloses an airborne system for generating and supplying oxygen and nitrogen. The gas generating device of the airborne system of the invention adopts the first air separation device including organic membrane separation technology, and the second air separation device of pressure swing adsorption technology. Air separation unit, the third air separation unit of solid electrolyte separation technology, obviously, the patent achieves theoretically a variety of different purity product streams by using three different types of gas separation technology—high purity oxygen (from solid electrolyte air Separation device), medium-purity oxygen (produced from pressure swing adsorption air separation device), low-purity nitrogen (produced from air separation device of organic membrane separation technology), however, because the type of technology used is too complicated, it is difficult to integrate and apply Applicable to the actual airborne operating environment, more or more system resources are consumed, and the maintainability and maintenance cost are also worse than those of a single technology type

Images