Development of Control Techniques for Mixing Small Coke at Bell-less Top Blast Furnace

Self Cite

To achieve low RAR operation by coke mixed charging, it is important to control coke segregation behavior in mixed layer at blast furnace top. In this study, a numerical simulator based on screening layer model was developed to estimate the distribution of mixed coke ratio in mixed layer. The results are summarized as follows: (1) The parameters required for the screening layer model to estimate the segregation behavior of the burden materials were determined by PIV test and numerical fitting. (2) The screening layer model containing parameters obtained by experiments and fittings was taken into the blast furnace burden distribution simulator. The simulation results showed that the distribution of mixed coke ratio of the small coke in the ore can be accurately estimated under the charging conditions of the actual furnace. (3) The influence of the difference in tilting direction of the rotating chute on the distribution of mixed coke ratio was evaluated. In the reverse tilting, the radial distribution of the mixed coke ratio became more uniform as compared with the forward tilting charging. Therefore, it is considered that reverse tilting is more effective for carrying out coke mixed charging.

Section: Validation Of Modelmentioning

confidence: 99%

Estimation of Particle Segregation Behavior in Ore-coke Mixed Layer Using Screening Layer Model

Terui¹,

Ichikawa²,

Kashihara³

2020

Self Cite

“…in blast furnace are very important. Conventionally as means for improving permeability in the blast furnace, improvement of high temperature properties of raw materials at the high temperature, [1][2][3][4] charging distribution control such as controlling of ore and coke particle size distribution, layer thickness in the radial direction at the top of blast furnace, 5,6) and mixing of coke into the ore layer [7][8][9][10] are effective. In particular, the combustibility of pulverized coal deteriorates under high PCR operation, 11,12) its improvement is effective for good permeability in the blast furnace.…”

Section: Effect Of Natural Gas Injection Point On Combustion and Gasimentioning

confidence: 99%

Effect of Natural Gas Injection Point on Combustion and Gasification Efficiency of Pulverized Coal under Blast Furnace Condition

Murao¹,

Fukada²,

Sato³

et al. 2019

Self Cite

The reduction of CO 2 emission from the ironmaking process is an important issue from the view of environmental problems typified by global warming in recent years. Low RAR (reducing agent rate) operation of the blast furnace is one of effective methods for reducing CO 2 emission. Injection of HRA (hydrogenous reducing agents) from the tuyere (where is the lower part of a blast furnace) is also effective measure. In this study, the influence of HRA injection point on combustion and gasification efficiency of pulverized coal (PC) in the case of simultaneous injection of HRA and PC from double-channel lance was examined by small scale combustion furnace and three-dimensional numerical simulation for permeability in the blast furnace. Combustion experimental conditions were in three cases, case 1: injected HRA from the outer side and PC from the inner side of double-channel lance, case 2: injected HRA from inner side and PC from outer side of double-channel lance and case 3: injected HRA and PC premixed. As a result, the combustion and gasification efficiency was increased in the order of case 1, case 2 and case 3. The rate of combustion and gasification of PC was investigated in case1. Not only the oxidation reaction was also accelerated CO 2 and H 2 O gasification reaction in the case of simultaneous injection HRA and PC. A three-dimensional numerical simulation of the experimental furnace was conducted, we confirmed the increase of combustion temperature, the acceleration of oxygen consumption and gasification reaction as with the experimental results in the case of simultaneous injection HRA and PC.

“…23,24) Therefore, it was thought that the discharge pattern of the mixed coke ratio from the lower bunker changed depending on the stacking condition of the small coke in the lower bunker. Figure 9 shows the stacking conditions of the ore and small coke charged in the lower bunker of the rectangular model in Base, Case 2 and Case 3.…”

Section: Effect Of Small Coke Stacking Condition On Discharge Behaviomentioning

confidence: 99%

Development of New Charging Technique for Mixing Coke in Ore Layer at Blast Furnace with Center Feed Type Bell-less Top

Kashihara¹,

Iwai²,

Ishiwata³

et al. 2017

Self Cite

Improved permeability and increased gas utilization have been desired in order to achieve low coke rate operation of blast furnaces. Coke mixed charging in the ore layer is one of the effective measures for realizing these improvements. A new charging technique for mixing small coke in the ore layer at a blast furnace with a center feed type bell-less top was developed and investigated in an experiment with a 1/18.8 scale model of an actual blast furnace at JFE Steel. By the new charging technique that small coke was charged in the determined port of the upper bunker before ore was charged in the upper bunker, the discharge pattern of the mixed small coke discharged from the bell-less top was improved, and the radial distribution of the mixed small coke ratio at the furnace top after the mixed materials were charged in the blast furnace was also improved. The new charging technique was applied to an actual blast furnace at JFE Steel, and improvement of gas permeability and a decrease in the coke rate were confirmed.