The multi-purpose smelting unit MAGMA can be used for waste- free processing of high-ash thermal coals (ash content up to 35%) for the generation of electric power.

Production capacity of MAGMA for incineration of high-ash thermal coal is 50-100 tons per hour. Production of saleable electric power is up to 90 MWh.

Principally, two routes of processing of high-ash coal can be implemented.

Processing Route 1 – 

• Incineration of coal in the smelting chamber of the unit in air enriched with oxygen, on the layer of the molten slag;

• After burning of the  formed flue  process  gases  in a heat-recovery power boiler installed over the smelting  chamber of MAGMA;

• Production of electric power by traditional processing route used in thermal power industry.

When burning high-ash thermal coal in MAGMA, ash contained in it is smelted and dissolved in the slag bath.

Temperature of molten slag in the smelting   chamber is 1500- 1600°C. This allows adjusting the composition of the slag being smelted by adding fluxes.

Slag is used for the production of cast-slag products or cast-slag crushed stones that by their quality are not inferior to natural granite crushed stones (Table 4 below).

Principal physical and mechanical properties of cast-slag crushed stones –

The dust captured by the gas treatment system is injected by injectors into the smelting chamber to the molten slag, where it is assimilated by slag. 

Processing Route 2 – 

• High-temperature gasification (incomplete burning) of high-ash thermal coal in the smelting  chamber of  the  unit  on the  layer of  the  molten slag.   The produced gas is mainly composed of CO and  H2  and some  quantity of water  vapour;
• Cooling of gas in a waste heat recovery boiler & passing the steam in a turbine for generating electrical power in the first cycle.  Cleaning of gases  from  dust and de-watering;
• Generation of electric power in the second cycle from dried gases in a gas turbine.
• Generation of electric power in the third cycle, in a waste heat recovery boiler & steam turbine, using medium temperature tail gases of a gas turbine.

Chemical composition of molten slag is also adjusted by adding flux and it is used at a later stage for production of saleable cast-slag products.

The dust captured by the gas treatment system is injected into the molten slag.  Thus, environmentally clean and waste-free processing of high-ash thermal coal is achieved.

When incinerating high-ash coal, partial reduction is possible of iron from oxides contained in the ash. The additional saleable product thus produced is used in production of steel at a later stage.

MAGMA can also be used for processing of waste from the concentration (beneficiation) of thermal coal.

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