Moisture in the Combustion Analysis of Coal – Lesson 6

How do you consider moisture in the combustion analysis of coal?

When analyzing coal particles (burning particles) containing moisture, selecting the Wet Combustion option will cause the moisture content of the moisture to be reduced by the evaporation of the droplets and the boiling of the droplets before volatile components of the coal particles start to devolatize evaporation - and the process of boiling can be considered. However, the Wet Combustion option is only available when using the Eddy-Dissipation model in the vapor phase combustion model.

If you use a gas-phase combustion model diffusion combustion model of (non-premixed combustion) for coal combustion, there are two approaches:
1. Mixture fraction model: fuel flow chart and the off-gas (water / volatile component)
2. Mixed fraction model: fuel flow chart, 2 order is off-gas (water / volatile component)
Although moisture can be considered in the diffusion combustion model, the water will not obey the laws of evaporation and boiling of liquid droplets, it will be released by the law of the de-volatile along with the volatile components.

To set the Wet Combustion:
1. In Define->Injection ... enable Wet Combustion options in the Wet Combustion tab
2. Select the evaporating/boiling particle from the Liquid Material drop-down list
3. Enter the volume fraction of liquid to be present in the particles for Liquid Fraction
4. Select the chemical species in the gas phase generated by the evaporation and boiling laws from the Evaporating Species drop-down list.