填充床中的气粉流行为和高炉两段式喷煤的研究

摘要

该篇论文旨在阐明填充床中气粉两相流的粉体行为,并开发一种新的高炉煤粉喷吹工艺.考虑到未燃煤粉的行为及其对高炉生产的影响,该文首先回顾了填充床中压降及粉体滞留的分布情况,未燃煤粉保护焦炭的先决条件和未燃煤粉对高炉炉衬的冷却作用.然后,利用实验室二维冷态高炉模型考察了填充床中气粉两相流的堵塞行为,粉体堵塞分布和其对料柱压差的影响.结果表明,料柱压降主要发生在料柱下部,粉体堵塞也主要在下部.而且下部粉体堵塞是下部压降急剧上升的主要原因.该文根据理论分析和实验室研究结果,提出了两段式喷吹煤粉新方案,即在在原有传统喷吹工艺中煤粉从高炉风口喷入外,在高炉软熔带上部、炉腰或炉身下部的区间段里设置第二段喷吹煤粉喷枪孔,插入第二段喷枪,喷入煤粉.研究结果表明,两段式喷吹有利于煤粉在高炉料柱内的均匀分布,减轻滴落带内的局部过量积粉,降低高炉全压差,是一种有效地提高煤粉喷吹率的新技术.实验室试验结果认为:两段式喷吹煤粉工艺在无其他任何辅助技术条件下,1)提高煤粉的喷吹量.通过第二段喷吹,实现了炉内未燃煤粉的分散滞留,提高了料柱的透气性,有利于高炉顺行,可增加喷煤量30~50kg/tHM;2)有效地保护炉内焦炭的机械强度.从第二段喷枪喷入的煤粉直接参与该区域碳的气化反应,替代了部分焦炭参加气化反应,从而保护了炉内焦炭的强度和机械性能,使料柱具有较好的透气性;3)有利于延长高炉寿命.第二段喷入的煤粉参加气化反应时,将吸收煤气中的热量,不仅提高高炉热利用率,而且降低炉墙处温度,减轻冷却壁的热负荷,有利于延长其使用年限,提高高炉寿命.现场试验检验证明了两段式喷吹煤粉工艺的有效性和系统设计的合理性:保证连续喷吹和高炉操作的稳定,在保持喷煤量基本不变的前提下提高料柱透气性指数约5.43％、增产约12.31％,取得了良好的经济效益.试验结果表明该工艺具有很好的推广使用价值和显著的经济与社会效益.

目录

文摘

英文文摘

声明

ACKNOWLEDGMENTS

NOMENCLATURE

CHAPTER ONE LITERATURE REVIEW

1.1 INTRODUCTION AND DEVELOPMENT OF PCI PROCESS INTO BLAST FURNACE IN INTEGRATED WORKS

1.1.1 BACKGROUND OF PCI PROCESS

1.1.2 DEVELOPMENT OF PCI PROCESS

1.2 INFLUENCE OF PCI PROCESS ON BF OPERATION

1.3 GENERAL STUDY ON PROCESS OF PCI

1.3.1 STUDY ON PC BEHAVIOR

1.3.2 STUDY ON GAS-POWDER TWO PHASE FLOW CONTAINING UPC AND COMPUTER SIMULATION

1.4 IMPROVING MEASURES ON PCI PROCESS

1.4.1 ADJUSTING DISTRIBUTION OF BURDEN INSIDE BF

1.4.2 ADJUSTING BLAST PARAMETERS

1.4.3 IMPROVING RAW MATERIAL AND FUEL

1.4.4OPTIMUMIZATION OF COAL MIXTURE AND INCREASING REPLACEMENT RATIO

1.4.5 OXYGEN ENRICHMENT TO INCREASE COMBUSTION RATE OF PC

1.5 NEW APPROACH TO INCREASE PCR BY MEANS OF UPC REDISTRIBUTION

1.6 THESIS OUTLINE

CHAPTER TWO PRELIMINARY STUDIES FOR BI-PCI PROCESS

2.1 FUNDAMENTALS OF GAS-POWDER TWO PHASE FLOW IN BI-PCI

2.2 BEHAVIOR OF UPC

2.2.1 CONSUMPTION RATE OF UPC INSIDE BF

2.2.2 PROTECTIVE EFFECT OF UPC ON COKE STRENGTH

2.2.3 COOLING EFFECT OF UPC'S GASIFICATION REACTION

2.3 SUMMARY

CHAPTER THREE LABORATORY STUDY OF BI-PCI PROCESS

3.1 EXPERIMENTAL APPARATUS AND METHOD

3.1.1 EXPERIMENTAL APPARATUS

3.1.2 EXPERIMENTAL METHOD

3.2 PRESSURE DROP AND POWDER HOLDUP OF GAS-POWDER TWO PHASE FLOW IN PACKED BED

3.2.1 DISTRIBUTION OF PRESSURE LOSS

3.2.2Distribution of Holdup

3.3 COMPARISON EXPERIMENTS BETWEEN CONVENTIONAL PCI AND BI-PCI

3.3.1 COMPARISON OF PRESSURE LOSS DISTRIBUTION BETWEEN CONVENTIONAL PCI AND BI-PCI

3.3.2 COMPARISON OF HOLDUP DISTRIBUTION BETWEEN CONVENTIONAL PCI AND BI-PCI

3.4 ANALYSIS

3.4.1 EFFECT OF UPC DISTRIBUTION IN PACKED BED ON PRESSURE DROP

3.4.2 PROTECTIVE FUNCTION OF UPC ON COKE STRENGTH UNDER BI-PCI

3.4.3 EFFECT OF UPC GASIFICATION REACTION ON THERMAL BURDEN OF FURNACE LINING UNDER BI-PCI.

3.4.4 ADVANTAGES OF BI-PCI PROCESS

3.5 EFFECTS OF OPERATIONAL PARAMETERS ON BI-PCI PROCESS

3.5.1 EFFECT OF GAS RATE ON HOLDUP DISTRIBUTION

3.5.2 EFFECT OF POWDER RATE ON HOLDUP DISTRIBUTION

3.6 SUMMARY

CHAPTER FOUR INDUSTRIAL TEST OF BI-PCI PROCESS

4.1 CONDITIONS OF INDUSTRIAL TEST

4.1.1 FACILITY CONDITIONS

4.1.2 TEST CONDITIONS

4.2 TEST RESULTS AND ANALYSIS

4.2.1 PRODUCTIVITY INCREASED

4.2.2 PERMEABILITY IMPROVED

4.2.3 OTHER OPERATIONAL PARAMETERS

4.3 SUMMARY

CHAPTER FIVE CONCLUSIONS AND RECOMMENDATIONS FOR FURTIHER WORK

5.1 SUMMARY OF CONCLUSIONS AND ACHIEVEMENTS

5.2 RECOMMENDATIONS FOR FURTHER WORK

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