Self-Reduction Behavior of Bio-Coal Containing Iron Ore Composites

Abstract

The utilization of CO2 neutral carbon instead of fossil carbon is one way to mitigate CO2 emissions in the steel industry. Using reactive reducing agent, e.g., bio-coal (pre-treated biomass) in iron ore composites for the blast furnace can also enhance the self-reduction. The current study aims at investigating the self-reduction behavior of bio-coal containing iron ore composites under inert conditions and simulated blast furnace thermal profile. Composites with and without 10% bio-coal and sufficient amount of coke breeze to keep the C/O molar ratio equal to one were mixed and Portland cement was used as a binder. The self-reduction of composites was investigated by thermogravimetric analyses under inert atmosphere. To explore the reduction progress in each type of composite vertical tube furnace tests were conducted in nitrogen atmosphere up to temperatures selected based on thermogravimetric results. Bio-coal properties as fixed carbon, volatile matter content and ash composition influence the reduction of iron oxide. The reduction of the bio-coal containing composites begins at about 500 °C, a lower temperature compared to that for the composite with coke as only carbon source. The hematite was successfully reduced to metallic iron at 850 °C by using bio-coal, whereas with coke as a reducing agent temperature up to 1100 °C was required.

A Numerical Study of Scenarios for the Substitution of Pulverized Coal Injection by Blast Furnace Gas Enriched by Hydrogen and Oxygen Aiming at a Reduction in CO2 Emissions in the Blast Furnace Process

“…The authors tested and modified the available models and data from the Literature [4,8,[10][11][12][13][14][15][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] to implement the rate equations taken into account for these reactions. The local flow, composition, and temperature conditions are used to describe the exchanges of energy interphase and momentum, which are formulated with a basis on fundamental relations [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. These formulations were adjusted to the blast furnace conditions [10,15].…”

Replacing Fossil Carbon in the Production of Ferroalloys with a Focus on Bio-Based Carbon: A Review

“…Another option to include biomass in the production route of ferrochromium is the replacement of coke or coal during the sintering operation to agglomerate chromite fines, which was already investigated several times recently for the sintering of iron ore [123][124][125][126][127][128][129][130][131][132][133][134] and the pelletizing of iron ore [34,35,48,54,119,135]. However, there are also difficulties to overcome when charcoal is used for sintering.…”

Experiences of Bio-Coal Applications in the Blast Furnace Process—Opportunities and Limitations

“…Torrefied sawdust & torrefied and pelletized sawdust [21][22][23][24]28,29] TSD & TSDP Torrefied wood at higher temperature, IMPCO [27] TW M1 Torrefied wood at higher temperature, FLEXCOKE [30] TW M2 Torrefied/pyrolyzed wood at even higher temperature [30] TW H Pyrolyzed charcoal of barbecue type [22,23,[30][31][32] CC Highly torrefied white pellets produced from sawdust [21] HTT Pyrolyzed wood chips [21] PWC The effect of using different types of bio-coals in coke-making was investigated using a technical scale coking retort in tests with 2.5 to 5% addition, and in a semi-industrial scale with 2 to 3% addition; all carbonization tests were made at DMT [33]. The retort is charged with 11 kg of coking coal blend, and after carbonization, the coke is tested for CSR/CRI according to the standard method.…”