Both the names seem very similar but there must be some very important differences.Please highlight them for me.
In a Midrex Process, hydrogen-rich gas (produced by cracking natural gas) is used in a shaft furnace to reduce iron ore in a solid-state. The product is a sponge iron.
In a Corex Process, two units are used. In the bottom is a melter-gasifier, where pre-reduced raw materials are melted with noncoking coal and oxygen. The gas from this unit is ascending into a pre-reduction shaft, were iron ore/sinter/pellets and fluxes are reduced and heated.
Dear Koyal,
Almost they are same reduction process. Basic differences between two are carbon dioxide gas emission.
1. Direct CO2 emissions of COREX is higher in comparison to MIDREX. Considering the credits of export gases for power generation, the total CO2 emission of COREX have advantages only when the COREX is joined with high-efficiency generating units which efficiency is greater than 45% and CO2 emission factor of the grid is higher than 0.9 kgCO2/kWh.
2. MIDREX operation is simple in comparison to COREX. MIDREX uses fastest start-up.
3. MIDREX process runs without coke, emits less CO2 and thus is gathering attention as an alternative process for blast furnace ironmaking.
4. COREX is smelting reduction process, whereas MIDREX is gas based shaft reduction process. The gas leaving in the corex, the reduction shaft is cooled and cleaned and is suitable for a wide range of applications (e.g., power generation, DRI production or use in reheating furnaces). Midrex is an innovative ironmaking process, developed for the production of direct-reduced iron (DRI) from iron ores and primarily natural gas.
5. Overall operation and production cost for COREX is usually less in comparison to MIDREX.
Ashish
Dear Marcus,
Almost they are same reduction process. Basic differences between two are carbon dioxide gas emission. Couple of simple comparisons are given below.
1. Direct CO2 emissions of COREX is higher in comparison to MIDREX. Considering the credits of export gases for power generation, the total CO2 emission of COREX have advantages only when the COREX is joined with high-efficiency generating units which efficiency is greater than 45% and CO2 emission factor of the grid is higher than 0.9 kgCO2/kWh.
2. MIDREX operation is simple in comparison to COREX. MIDREX uses fastest start-up.
3. MIDREX process runs without coke, emits less CO2 and thus is gathering attention as an alternative process for blast furnace ironmaking.
4. COREX is smelting reduction process, whereas MIDREX is gas based shaft reduction process. The gas leaving in the corex, the reduction shaft is cooled and cleaned and is suitable for a wide range of applications (e.g., power generation, DRI production or use in reheating furnaces). Midrex is an innovative ironmaking process, developed for the production of direct-reduced iron (DRI) from iron ores and primarily natural gas.
5. Cost for COREX is usually less in comparison to MIDREX.
Ashish
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