TRP0033 - PCI Coal Combustion Behavior and Residual Coal Char Carryover in the Blast Furnace of 3 American Steel Companies During Pulverized Coal Injection (PCI) at High Rates

TRP0033 - PCI Coal Combustion Behavior and Residual Coal Char Carryover in the Blast Furnace of 3 American Steel Companies During Pulverized Coal Injection (PCI) at High Rates
Author:
Publisher:
Total Pages: 412
Release: 2005
Genre:
ISBN:

Combustion behavior of pulverized coals (PC), gasification and thermal annealing of cokes were investigated under controlled environments. Physical and chemical properties of PCI, coke and carbon residues of blast furnace dust/sludge samples were characterized. The strong influence of carbon structure and minerals on PCI reactivity was demonstrated. A technique to characterize char carryover in off gas emissions was established.

Feasibility of Coal Burning in Catalytic Combustors

Feasibility of Coal Burning in Catalytic Combustors
Author: P. M. Goldberg
Publisher:
Total Pages: 2
Release: 1981
Genre: Coal
ISBN:

The results of this study show that pulverized coal can be burned in a catalytic combustor. Pulverized coal combustion in catalytic beds is markedly different from gaseous fuel combustion. Gas combustion gives uniform bed temperatures and reaction rates over the entire bed length and, depending on flow conditions and bed geometry, little combustion may occur downstream of the bed. For the bed configurations, fuel supplies, and test conditions studied, pulverized coal combustion results in significant temperature and reaction gradients over the bed length and substantial combustion downstream of the bed. Thus, for pulverized coal combustion, the bed acts mainly as an indicator and stabilizer of combustion. A significant portion of the combustion process, primarily that associated with char burnout, occurs downstream of the bed.

Char Formation, Transportation and Consumption in the Blast Furnace and Its Impact on Coke Rate (Charfoco)

Char Formation, Transportation and Consumption in the Blast Furnace and Its Impact on Coke Rate (Charfoco)
Author:
Publisher:
Total Pages:
Release: 2019
Genre:
ISBN: 9789279983245

In the past, blast furnace coal injection research mainly focused on combustion of injection coal in the raceway. However, it could be assumed that coal is anyway not able to fully combust, particularly at high injection rates, and unburnt residues leave the raceway as char. The char evolution and subsequent consumption depends on the raceway characteristics, which depend on coal conversion. Both groups of factors were investigated with conversion tests, as well as raceway measurements. Generally, the char evolution is seen to manifest itself as a negative impact, but this may depend on the blast furnace conditions and injection coal characteristics. Char effects might deteriorate the blast furnace operation and stability (i.e. lower burden permeability or higher carbon losses in the flue dust). Nonetheless, char could also be advantageous by contributing toward the increase in coke reactivity thereby lowering the thermal reserve zone temperature. It was shown that the coal combustion highly depends on coal grain size and only marginally on oxygen enrichment. Effects of oxygen enrichment on maximum coal injection rate might be more related to char consumption, rather than coal conversion. Despite low conversion of granular coal under blast furnace raceway simulation conditions, granular coal injection is possible at high rates, obviously due to its consumption outside the raceway. Blast furnace operation experience with coals, like operational benefits or transport behaviour could be confirmed. Char impact on ferrous burden behaviour highly depends on temperature and gas composition and is difficult to predict from the performed tests. Several raceway measurement techniques were successfully developed and applied at pilot scale and at a real blast furnace. Raceway size, temperature and changes in the gas composition could be shown. The raceway size depends on the location of the tuyère in relation to blast inlet and tap hole and changes significantly over time, indicating raceway collapses. Gas and temperature measurements of the BF interior were performed: New insights regarding the impact of high coal injection rates on the blast furnace inner state were gained by gas and temperature measurements of the blast furnace inside and confirmed with mathematical modelling.

Coal Combustion Under Conditions of Blast Furnace Injection. Final Technical Report, September 1, 1992--August 31, 1993

Coal Combustion Under Conditions of Blast Furnace Injection. Final Technical Report, September 1, 1992--August 31, 1993
Author:
Publisher:
Total Pages: 32
Release: 1993
Genre:
ISBN:

A potentially new use for Illinois coal is as a fuel injected into a blast furnace to produce molten iron as the first step in steel production. Because of its increasing cost and decreasing availability, metallurgical coke is now being replaced by coal injected at the tuyere area of the furnace where the blast air enters. The purpose of this study is to evaluate the combustion of coal during the blast furnace injection process and to delineate the optimum properties of the feed coal. This investigation is significant to the use of Illinois coal in that the limited research to date suggests that coals of low fluidity and moderate to high sulfur and chlorine contents are suitable feedstocks for blast furnace injection. During the first phase of this project a number of the objectives were realized, specifically: (1) a blast furnace sampling system was developed and used successfully to collect samples inside an active furnace; (2) two sets of blast furnace samples were collected and petrographic analysis showed that char derived from injected coal is entering the reduction zone of the furnace; (3) a coal/char sampling probe was designed and fabricated; (4) the completion of a program of reactivity experiments on the injected coal char, blast furnace coke and Herrin No. 6 char. The results of the reactivity experiments indicate that Herrin No. 6 coal is similar or even superior to coals now being used in blast furnace injection and that additional testing is warranted.

Coal Combustion Under Conditions of Blast Furnace Injection. [Quarterly] Technical Report, 1 March 1993--31 May 1993

Coal Combustion Under Conditions of Blast Furnace Injection. [Quarterly] Technical Report, 1 March 1993--31 May 1993
Author:
Publisher:
Total Pages: 16
Release: 1993
Genre:
ISBN:

A potentially new use for Illinois coal is its use as a fuel injected into a blast furnace to produce molten iron as the first step in steel production. Because of its increasing cost and decreasing availability, metallurgical coke is now being replaced by coal injected at the tuyere area of the furnace where the blast air enters. The purpose of this study is to evaluate the combustion of coal during the blast furnace injection process and to delineate the optimum properties of the feed coal. The basic program is designed to determine the reactivity of both coal and its derived char under blast furnace conditions and to compare the results to similar properties of blast furnace coke. The results of the first two experiments in which coal char pyrolyzed in nitrogen at 1000°C in an EPR were reacted isothermally in air at 1000°C and 1200°C. The reactivity values of the same char in these two experiments were different by an order of magnitude. The char reactivity at 1000°C was 9.7 x 10−4 grams per minute while the reactivity. of the char at 1200°C was 1.6 x 10−3 grams per minute. These results suggest that the temperature of the blast air in the tuyere may be critical in achieving complete carbon burnout.

Injectant Coal Gasification, Char Formation and Char Utilisation at High Injection Rates

Injectant Coal Gasification, Char Formation and Char Utilisation at High Injection Rates
Author: European Communities
Publisher:
Total Pages:
Release: 2004
Genre:
ISBN:

The aim of this project was to carry out an integrated laboratory, pilot and plant scale investigation of injectant coal gasification, char formation and properties, the effect of char on melting zone behaviour and the utilisation of char in terms of top gas dust carryover at high levels of injection. Laboratory-scale studies undertaken by Corus and Imperial College of Science, Technology and Medecine (ICSTM), focused on the degree of burnout of injectant coals, morphology and reactivity of resultant chars and an evaluation of the potential for the formation of soot precursors. Extents of gasification were related to parent coal properties and correlations between char morphology and parent coal VM content were established. The experiments also determined rates of particle mass loss under the variety of conditions that exist within the coal injection plume and made a significant contribution to the understanding of how and where volatiles are released and whether chars will be completely gasified. Centra Sviluppo Materiali (CSM) concentrated on the influence of char particles on the rheological properties of the ferrous materials in the blast furnace burden. Laboratory-scale tests under simulated blast furnace conditions on mixtures of ferrous burden, coke and char were conducted in the SMEDRA (Softening MElting DRipping Apparatus). The presence of char in the ferrous materials caused changes to the extent of initial dripping and to the starting temperature of this phenomenon. These changes correlated to the amount of char added and to the characteristics of the parent coal (the VM content and whether pulverised or granular grade) and would affect the position and the shape of the melting zone in the blast furnace. At the plant scale , ThyssenKrupp Stahl sampled blast furnaces operating with coal injection and characterised the dust collected. Tests were carried out based on the knowledge that increased graphitisation of carbon occurs with rising temperature, allowing the source of the carbon to be identified. With a new analytical method, Microwave-Assisted Dissolution, it was possible to exactly quantify the smallest quantities of graphite in top gas dust. The amount of dust discharged through the furnace top was largely determined by the percentage of non-carbonaceous components, but a clear correlation between the quantity of discharged dust and the quantity of carbonaceous components was also found. The findings also indicated that the carbon in the dust from the centre of the furnace comes mainly from ungasified injectant coal char.