What factors need to be considered when adding solubilizers to coal powder

The amount of flux to be added is determined based on the ash melting point, to ensure even distribution of the flux; moreover, it should not be used in excess, as this can lead to scaling in the synthesizer’s cooler.

To ensure smooth slag discharge from the gasifier, the operation temperature for gasification must be 100–150°C higher than the ash melting point; if T3 is high, it becomes necessary to raise the gasification operation temperature, which in turn affects the economic efficiency of the gasifier’s long-term operation. Therefore, the lower the T3, the more favorable the vaporization. Generally, a flux is added to change the ash melting point in order to ensure the proper operation of the gasification furnace. The ash composition generally has little impact on the gasification reaction, but excessively high levels of certain components in the ash can affect its melting characteristics, leading to poor slag discharge from the gasification furnace or blockages at the slag outlet. Regarding the selection of fluxes and their addition amounts, it is necessary to take into account the composition of coal ash; by adding certain components (usually alkaline substances), the relative composition of the ash can be adjusted in order to improve its melting characteristics. The addition of fluxes will increase operating costs and capital investment, but these increases can be offset by reducing the gasification temperature and saving on oxygen and coal consumption. Generally, coal with a lower T3 value is favorable for Shell gasification. Note: The applicable ranges for ash content and ash fusion point are as follows (generally, an ash content of 8–15% is suitable; an ash fusion point below 1350°C is preferred, otherwise, using fluxes becomes less economical)