Oxygen-enriched combustion-supporting energy-saving technology

Energy-saving characteristics of oxygen-enriched combustion

1、The influence of oxygen enrichment concentration on energy saving effect:

It is generally believed that the energy-saving effect is proportional to the oxygen concentration in the oxygen-enriched air, that is, at the same combustion temperature, the greater the oxygen concentration, the more conducive to the full combustion of the fuel, and the more obvious the energy-saving effect. As early as 1982, Japan successfully developed oxygen-enriched equipment with an oxygen concentration of up to 40% and a complete set of related combustion technologies. Experiments have proved that at a certain temperature, the use of 23% oxygen-enriched combustion can save energy by 10% to 25%; the use of 25% oxygen-enriched combustion can save energy by 20% to 40%; the use of 27% oxygen-enriched air can save energy by 30% to 50%. %; The impact of using more than 30% oxygen-enriched combustion to save energy is not significant. Therefore, when the low-concentration oxygen-enriched technology route is adopted, an oxygen concentration of about 30% is more appropriate.

The application of oxygen-enriched combustion, due to the combined effect of the increase of the furnace gas blackness and the increase of the flame temperature, makes the radiant heat transfer ability of the fuel gas to the furnace and products greatly improved. For tunnel kilns, if other conditions permit, the heating speed of the kiln can be accelerated and the production output can be increased. Through the extensive use of oxygen-enriched combustion in industrial kilns abroad, it is proved that the comprehensive energy saving rate of 25-30% oxygen-enriched air for combustion can reach 20-40%, of which 80% is achieved by increasing production output.

2、The influence of oxygen-enriched combustion on heat utilization:

As the oxygen concentration in the air increases, the heat utilization rate increases significantly. When ordinary air is used for combustion, the available heat is 42% when the heating temperature is 1300℃; when 26% oxygen-enriched combustion is used, the available heat is 56%, which is an increase of 33% year-on-year heat utilization. Therefore, it can be considered that the increase in oxygen concentration is proportional to the heat utilization rate.

In actual heating applications, it is unreasonable to only consider the combustion efficiency and ignore the heat transfer effect. The increase in oxygen concentration also increases the concentration of reaction products CO2 and H2O. The radiation force of CO2 and H2O vapor triatomic gases increases with the increase of temperature, the increase of gas concentration (or partial pressure) and the increase of gas layer thickness are strengthened, and the thermal conductivity and heat capacity are improved, thereby increasing the heat transfer ability. In addition, heated materials (such as ceramics) mainly rely on thermal radiation to obtain thermal energy in the high-temperature zone, and the radiation intensity is proportional to the fourth power of the temperature. Although the furnace temperature has not risen much, the heat radiation intensity has been greatly increased, and the heated material can obtain heat more easily, which greatly improves the thermal efficiency. Therefore, increasing the combustion temperature will greatly increase the heat transfer.