Rich (pure) oxygen baking device: more complete combustion, significant energy-saving effect

1、 At present, major energy users in the steel industry, such as sintering machine torches, ladle baking, scrap preheating, and scrap melting, all use air and fuel (natural gas, coke oven gas, mixed gas, converter gas, and blast furnace gas) to organize combustion technology. The prominent drawbacks are:

1) Low combustion flame temperature and long process time;

2) Insufficient flame stiffness and flame length result in poor uniformity of temperature field in local heating spaces;

3) The content of nitrogen oxides in flue gas is high, and most enterprises' direct flue gas emissions do not meet the standards or increase denitrification processes, which increases investment and maintenance costs;

4) The fuel consumption per ton of crude steel smelting is high, and the energy utilization rate is low, resulting in an increase in costs and a decrease in enterprise profit margins;

5) Large flue gas emissions, low fuel combustion efficiency, low waste heat recovery rate of flue gas, and low energy utilization rate have a significant impact on the environment and ecology.

(2) Characteristics of pure oxygen combustion technology

Pure oxygen combustion is another revolution in the combustion field of the steel industry, which is highly compatible with the technology of the above three pathways. Rich (pure) oxygen combustion is the use of pure oxygen or oxygen rich air (with an oxygen content greater than 21%) as a combustion aid during the combustion process. The basic principle of energy-saving in pure oxygen combustion technology can be clearly expressed from the combustion reaction equation:

When air assisted combustion: CH4+2O2+7.52N2=CO2+2H2O+7.52N2+heat;

When oxygen supports combustion: CH4+2O2=CO2+2H2O+heat.

In the air, the volume of O2 only accounts for 21%, while the volume of N2 reaches 79%. Pure oxygen combustion reduces the amount of N2 in the combustion medium that neither participates in nor promotes combustion reactions, thereby reducing the heat carried away by N2 in the flue gas and achieving the goal of energy conservation.

(1) Can significantly improve the utilization rate of low calorific value fuels

Due to the absence of nitrogen in the air, the relative combustion temperature of fuel and pure oxygen combustion is higher, which can improve the utilization rate of more low calorific value fuels, such as blast furnace gas. The utilization of low calorific value fuels can significantly save costs.

(2) Significantly reduce NOx and carbon emissions

Pure oxygen and fuel combustion, due to the absence of nitrogen in the oxidant, do not produce nitrogen oxides during high-temperature combustion. Secondly, the higher the combustion temperature of pure oxygen, the higher the energy that can be provided by heating the heating body at the same exhaust temperature, and the greater the relative fuel consumption, reducing carbon emissions to the atmosphere.

(3) Significantly increase energy efficiency and reduce operating costs

Table 1 Energy Saving Rate Accounting Table

project

Company

Air 1

oxygen

O2 content in the air

%

twenty-one

ninety-nine

N2 content in the air

%

seventy-nine

one

Air preheating temperature

℃

twenty

twenty

Natural gas preheating temperature

℃

twenty

twenty

Excess air coefficient

one point one

one point one

Air consumption coefficient

m3/m3

ten point one

two point one five

Smoke to fuel ratio coefficient

m3/m3

eleven point one

three point one five

N2 content in flue gas

%

seventy-two point two

one point three eight

Theoretical combustion temperature

℃

one thousand nine hundred and sixty-five

three thousand and seventy-four

Natural gas calorific value

kcal/m3

eight thousand and three hundred

eight thousand and three hundred

Heat carried away by flue gas (1100 ℃)

kcal/m3

four thousand five hundred and twenty-three

one thousand two hundred and seventy-two

Proportion of flue gas heat loss to total heating

%

fifty-four point five

fifteen point three

(4) Low smoke exhaust and friendly workshop environment

Due to the absence of nitrogen parameters in pure oxygen combustion, the smoke exhaust volume significantly decreases, and the decrease in smoke exhaust volume also greatly reduces the impact and damage of waste smoke on the surrounding ecological environment.

(5) Significantly improve heating efficiency and shorten process time

Pure oxygen combustion has a high flame temperature, which increases the relative air combustion temperature by about 1000 ℃. It has strong thermal radiation and can significantly shorten the baking time in multiple fields such as ladle baking and iron ore sintering, improving the production capacity of the process production line.

Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. undertakes the energy-saving technical renovation project of large steel enterprise gas roaster and scrap preheating and baking device. Welcome to call (WeChat synchronization): 15713691937 13849187223.

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