Relationship between pressure and flow of coke oven gas

The relationship between coke oven gas pressure and flow rate: the pressure is constant, and the flow rate decreases when the downstream pressure increases; When the pressure increases and the downstream pressure remains the same, the flow rate increases.

Coke oven gas is a mixed gas composed of many gases, which has the characteristics of low flow rate, low density, tar, dust and moisture, so the measurement of the relationship between pressure and flow rate of coke oven gas is much more complicated than that of single-component gases such as oxygen and nitrogen, and it is much more difficult to obtain accurate measurement values.

In recent years, we have tried to use the rotating flowmeter, vortex flowmeter, thermal flowmeter and other flowmeters with different measuring principles in the coke oven gas pipeline, but they are all limited by the characteristics of coke oven gas, and the application effect is not very satisfactory. Finally, the traditional differential pressure flowmeter is still used to measure most coke oven gas.

Main factors affecting the measurement results of coke oven gas flow;

(1) The coke oven gas with dust must contain dust and tar, so after years of use, dust and tar will inevitably be deposited, forming uneven thickness deposits inside the pipeline.

(2) Density change of coke oven gas Coke oven gas is a mixed gas composed of hydrogen, methane, carbon monoxide, unsaturated hydrocarbon, carbon dioxide, nitrogen, oxygen and water vapor. When the temperature, pressure and relative humidity of the measured gas are the same as the design values of the orifice plate, due to other reasons such as production process, the volume percentage of each component of the measured gas has changed, which makes the gas density inconsistent with the design state and will affect the accuracy of the measured value.

(3) Changes of pressure, temperature and humidity of coke oven gas.

Characteristics of coke oven gas:

1, the calorific value of coke oven gas is16720-18810kj/m3, and the combustible composition is relatively high (about 90%).

2. Coke oven gas is colorless and smelly.

Coke oven gas is toxic because it contains carbon monoxide and a small amount of H2S.

4. Coke oven gas contains a lot of hydrogen, with fast combustion speed and short flame.

5. If the coke oven gas is not purified well, it will contain more tar and naphthalene, which will block pipes and fittings and bring difficulties to the fire adjustment work.

6, the ignition temperature is 600~650℃.

7. Coke oven gas contains H2(55~60%), CH4(23~27%), CO(5~8%), CO2( 1.5~3.0%), N2(3~7%), O2 (