天然气富氧燃烧特性分析

Oxygen-enriched Combustion Characteristics of Natural Gas

随着全球各个国家对能源需求的不断增长和对环境保护意识的逐渐增加,我国以煤炭为主要消耗能源的现状已不符合可持续发展的理念。现阶段我国正在对清洁能源天然气大力推行,使得天然气在我国能源消耗中占比越来越大。如何提高能源燃烧效率的同时使污染物的排放得到减少,已成为了目前全球各个国家迫切需要解决的问题之一。富氧燃烧一种是利用助燃气体以高于空气中的氧气浓度进行燃烧的技术。能降低燃料的燃点,加快火焰的燃烧速度,燃烧过程中烟气含量减少,传热能力增强,从而大幅度提高燃烧效率,节约能源。但是在富氧燃烧过程中,必定产生比空气燃烧高得多的高温。这些高温会使空气中以及燃料中的N_2反应生成污染物NO_x,如何减少NO_x的生成量,就是富氧燃烧目前需要解决的问题。在建立好燃烧器,并完成网格划分之后,进行了富氧燃烧的模拟分析,从而得到了天然气在不同条件下的燃烧特性。并且分别研究了当助燃气体氧气氮气比例不同以及氧气和二氧化碳配比不同的NO的生成量,从而得到富氧燃烧时,减少NO_x生成量的最佳燃烧条件。

With the increase of world energy demand and environmental protection consciousness, China＇s current energy consumption situation with coal as the main energy does not meet the concept of sustainable development. Now natural gas as clean energy is widely used in China. How to improve the energy efficiency of energy combustion and reduce emission of pollutants is one of the world＇s urgent problems. The oxygen-enriched combustion technology is to use combustion-supporting gas to increase the concentration of oxygen in the air for combustion, which can reduce the ignition of the fuel, accelerate the flame burning speed, reduce the content of flue gas during combustion, improve combustion efficiency, and save energy. But in the oxygen-enriched combustion process, higher combustion temperature will be produced. The higher temperature can cause the reaction of N_2 in the air and fuel to produce pollutants NO_x. How to reduce the amount of generated NO_x is a key problem to be solved for the oxygen-enriched combustion process. In this paper, a burner was established and its meshing was completed, numerical simulation of the oxygen-enriched combustion process was carried out, combustion characteristics of natural gas were obtained. And NO generation amounts of the oxygen-enriched combustion process under different ratio of oxygen to nitrogen as well as different ratio oxygen to carbon dioxide were studied, the optimum combustion conditions to reduce the amount of NO_x generat ion amount were determined.