Development of Injection Lance with High Combustibility for High Rate Coal Injection

A three-dimensional numerical model of pulverised coal injection has been developed for simulating coal flow and combustion in the tuyere and raceway of a blast furnace. The model has been used to simulate previously reported combustion tests, which feature an inclined co-axial lance with an annular cooling gas. The predicted coal burnout agrees well with that measured for three coals with volatile contents and particle size ranging between 20.2-36.4 % and particle sizes 1-200 mm. Many important phenomena including flow asymmetry, recirculating flow and particle dispersion in the combustion chamber have been predicted. The current model can reproduce the experimental observations including the effects on burnout of coal flowrate and the introduction of methane for lance cooling.

Section: Introductionmentioning

confidence: 99%

Three-dimensional Simulation of Flow and Combustion for Pulverised Coal Injection

Guo

Zulli²,

Rogers

et al. 2005

“…9) To improve combustion efficiency of pulverized coal, several kinds of injection lance have been proposed. They included double lance arrangement, 10) eccentric double lance arrangement, 11) high turbulence lance with diagonal edge, 12) swirl burner 13) for example. Purpose of these injection lance arrangements is enhancement of particle dispersion.…”

Section: Introductionmentioning

confidence: 99%

Convergent-Divergent Injection Lance for the Enhancement of Combustion Efficiency of Pulverized Coal at Blast Furnace

Murai¹,

Kashihara²,

Murao³

et al. 2016

Self Cite

To achieve a high rate injection of pulverized coal into a blast furnace, it is so important to increase a combustion efficiency of pulverized coal. Enhancement of particle dispersion is one of the measures to increase combustion efficiency by accelerating oxygen-coal particle mixture in blowpipe to tuyere region. To realize this, it is found that convergent -divergent injection lance designed on the basis of fluid dynamics has superior characteristics. Divergence angle of the lance is optimized as the maximum angle free from the flow separation phenomenon in the boundary layer and convergence angle of the lance is optimized considering the inertia of coal particle in the gas-solid two phase flow. Optimum divergence angle and convergence angle is found to be 7 and 5 degrees respectively. Direct observation results by offline apparatus, hot model experiments and even in the actual blast furnace proves that dispersion of pulverized coal particles is enhanced considerably.It is confirmed that permeability is improved at an actual blast furnace when the developed lances are installed. This result suggests that high combustion efficiency had been achieved by the enhancement of particle dispersibility.It is thought that the convergent -divergent lance can be one of the practical solutions for the stable operation with high rate injection of pulverized coal because the lance can be installed almost all blast furnaces easily by its simple configuration without a large amount of investment.

“…( R e ) gas flow in lower part of blast furnace, 23) ii) Model of particle motion in coke packed bed, [24][25][26] and iii) Model of plastics gasification.…”

Section: Modeling Of Flow Behavior Of Plastic Particles In the Lower mentioning

confidence: 99%

Flow Behavior of Plastic Particles in the Lower Part of Blast Furnace

Murai¹,

Asanuma²,

Sato³

et al. 2015

Self Cite

Injection of plastics into blast furnaces as an alternative reducing agent has been carried out for the purpose of mitigation of carbon dioxide emissions. Several studies on the pyrolysis of plastic particles have been reported, however flow behavior of plastic particles or unburnt char in actual blast furnace is not clear.In this study, hotmodel experiments and thermogravimetry analysis were conducted for the modeling of gasification and combustion behavior of plastic particles, then flow behavior of plastic particle and unburnt char in a blast furnace was calculated by numerical simulation. According to the observation results of combustion experiment, volatile matter of plastics seems to be evolved at the surface of the particles. Regarding reaction of char derived from plastics, thermogravimetry analysis showed that rate of gasification of unburnt char depended on the rate of heating. Gasification rate in the case of rapid heating condition tended to increase.As the results of numerical simulations, initial diameter of plastics and char diameter determined the flow behavior in the blast furnace. When relatively small plastic was injected or diameter of unburnt char was small, unburnt char went upward along with gas flow and most of it might be consumed at the cohesive zone. On the other hand, when relatively coarse plastics was injected and diameter of unburnt char was relatively coarse, it was suggested that unburnt char accumulated around the deadman.Therefore, it is considered that fine plastics injection is desirable for the stable operation of blast furnace.