八钢2500m3 C高炉低硅冶炼实践探索

八钢2500m3 C高炉低硅冶炼实践探索

雷春森，赵忠华，潘有斌

(宝武集团新疆八一钢铁股份有限公司)

一、前言

为保障下道工序炼钢降低冶炼成本，在C高炉进行低硅冶炼攻关试验，高炉低硅冶炼（生铁含Si小于0.45%）通过改善高炉的操作条件，采用合适的操作手段，在高炉炉况稳定顺行的基础上，在整个高炉内造成一个抑制硅还原的环境，从而获得Si含量较低的铁水，从源头上减少高炉内硅的还原数量，降低生铁含硅量可以使高炉能降低焦比提高产量。

二、现状调查

2.1、C高炉2022年8月至今生铁含Si情况:

2.2、低硅冶炼必备条件:

①炉况顺行无崩滑料、管道、悬料，下料均匀，煤气利用率稳定合适；

②原燃料质量要保证，成分稳定合适，入炉渣比＜330kg/t,

入炉干熄焦灰份＜12.5%，焦炭M40≥89，M10≤6.8，入炉干熄焦比例80%以上;（焦化分厂负责）

炉料结构要稳定不宜频繁调整，烧结比例控制在75%-80%，烧结碱度波动±0.05之内;（烧结分厂负责）

③作业区进行技能培训提高值班长操作技能，每天由作业长组织召开炉况评价操业会，每班班前班后对炉况进行评价总结不足；

④炉缸工作活跃热制度要充沛，渣铁流动性要好，渣温充足，风口明亮活跃；

⑤冷却系统无漏水，定期进行冷却壁及冷却介质检漏，风口小套、中套无漏水情况，关注每班水系统补水情况，对关键参数H2含量检测做到重点关注，保证冷却系统正常无漏水，异常情况及时汇报；

⑥风温设定1070-1100℃，保证渣铁物理热充足；

三、高炉低硅冶炼目标设定

结合目前C高炉8月份Si小于0.40占比46.89%,确定本次C高炉低硅冶炼攻关试验分两个阶段:

第一阶段（8月27日-9月7日）为Si＜0.40%,命中率达到60%;

第二阶段（9月8日-9月18日）为Si＜0.40%,命中率达到70%。

考虑下道工序炼钢对生铁含S的要求，本次攻关试验分阶段适当提高炉渣碱度，保持良好的造渣制度,现C高炉炉渣碱度为:1.06-1.10，

第一阶段将炉渣碱度提升至1.10-1.14

第二阶段将炉渣碱度提升至1.12-1.16

3.1、C高炉现入炉炉料结构为:

由上图可以看出，C高炉烧结矿占比为77.27%，钒钛占比7.58%（入炉Ti负荷20.06），生矿占比5.0%，伊钢球团占比10.15%；

入炉配加焦炭结构为：新区自产干熄焦:外购永鑫焦=85%:15%。

3.2、C高炉目前操作制度如下:

3.2.1、BV:4400-4450m3/min；TP:200kpa,静压及热负荷没有波动时执行平均△P≯上班平均△P+3 εBP=180，热负荷大幅上升时，前期适当减风避让（瞬时或均排压期间超限可先不减），K值＞5.0减风；②若静压周期波动时执行△P≯170KPa，减风（100-200），波动完毕要及时回风；）③静压没有波动时执行△P≯175KPa，减风（100-200），波动完毕要及时回风；）

3.2.2、BT：1030℃-1080℃(风温在范围内调整）；富氧:10800(根据炉顶温度和荒煤气温度可减氧)； 加湿：2000-5000，Tf范围2200-2300℃。§炉顶温度大于300℃打水。顶温控制在300以下，管道减风300-500避让。

3.2.3、SL:1.60m。SL选择1#、3#尺，如两个料尺偏差大于1m时，按浅尺大于1.0m放料，不得随意更改，（班中尽量不要人工干预探尺，连续干预不得大于2次）; 布料圈数:焦炭：43322，矿石:33321    α角:38.5度，

3.2.4、干基燃料比:525±3kg/t,折算燃料比:510±3kg/t，炉温高风温、加湿调剂。严禁燃料比低于操业方针下限操作。（前4小时和后4小时偏差＜3kg）每班调剂煤量≤3t,每班补焦量不得超过5t，PT：1490±10℃；[Si]:0.30-0.50,[Si]+[Ti]：0.50-0.8%；R2: 1.08-1.12倍,炉渣碱度超上限时，关注生铁【S】含量，【S】:0.030-0.045，碱度不做调整。

3.2.5、班料批：47±1批（禁止超上限不允许超49批）, 限氧因素影响做好统计。                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              

3.2.6、ΔP如超上限减风量100－200 m3/min，减至压量关系合适；如风压、压差突升，可适当减风；如顶压突升，采取减风压措施，待稳定后调顶压至匹配；若出现崩、滑料2次通知现工、管道1次或者崩、滑料3次通知作业长；炉温低于1450一炉通知现工，连续两炉通知作业长。

3.2.7、加强煤气利用率关注，如煤气利用率变化超过±2，立即查明原因（仪表、装料制度、原燃料）如不能确定立即汇报。

3.2.8、软水进水温度:≤43℃   工业水进水温度:≤35℃；（每班关注补水量，超过10方/班必须查清原因）

3.2.9、做好槽下过筛工作，T/H控制40以下。

3.2.10、炉前出铁管理：做好炉前出铁正点率，出铁间隔时间:0-15min，每天必须12-13炉。

四、C高炉低硅冶炼攻关实施措施及试验成果

4.1、统一操作:由作业区对四班操作工长统一培训，统一操作思路，每天召开操业会，制定操业方针；

4.2、送风制度:在送风制度上维持全风量、全风口喷吹等措施，提高风速与鼓风动能，使煤气在炉缸的初始分布合理，炉缸截面温度分布均匀，炉缸工作活跃，这对控制硅的还原和保证炉渣具有良好的脱硫性能提供了有利条件。现C高炉风量4400-4450Nm3/min维持；富氧为11000Nm³/h，视炉况稳定可将富氧提升至12000Nm³/h。

4.3、热制度:合理的炉缸热制度包括两个方面，一方面是炉缸要有足够高的温度，常用风口前理论燃烧温度来衡量，另一个方面炉缸要有充沛的热量储备，这一点对于低硅冶炼尤为重要。在高炉中，发生还原反应的温度很高。但过高的炉缸温度，势必造成SiO的大量挥发，不仅容易引起炉况难行甚至悬料，而且使得铁水含硅升高。因此冶炼低硅铁水时，应控制合理的理论燃烧温度。严格遵守操业，将PT控制在1480±10。

4.4、造渣制度：实现低硅冶炼，必须有合理的造渣制度相适应。在低硅冶炼条件下，合适的造渣制度，不仅使炉渣有足够的脱硫能力，保证合格的生铁质量，而且可以提高炉渣的熔化性温度，保持炉缸具有充足的物理热，同时还能降低渣中的活度，抑制渣中硅的还原。较高碱度的炉渣可使表面张力增加，对焦炭的润湿性下降，使硅发生还原反应的面积减小；与此同时,可提高炉渣的软化温度，对降低软熔带高度和保证炉缸有良好的热储备都是有利的；

4.5、适当提高顶压：炉顶压力提高以后，CO分压相应得到提高，从而抑制了SiO的生成，从而降低了硅的生成量。此外炉项压力提高以后，有利于高炉热量的下部集中，软熔带、滴落带的位置相对降低，减弱了硅生成的热力学和动力学条件，从而也有利于低硅冶炼的进行。提高炉顶压力，实现高压操作对低硅生铁的冶炼是非常有利的。现阶段C高炉顶压为195kpa，第一阶段将顶压提升至200kpa，第二阶段将顶压提升至203kpa。

4.6、装料制度：采用合理的装料制度，优化炉料在高炉内的分布，对于高炉稳定顺行、控制适合的软熔带位置，提高煤气利用率具有重要意义。搞好下部调剂，控制适宜的鼓风动能，可以形成炉缸初始煤气流的合理分布，保证炉缸工作均匀活跃。因此，上下部调剂相结合，维持中心和边缘煤气流的合理分布，保证高炉稳定运行，为实现高炉低硅强化冶炼的重要保证，保持合理的布料模式，以稳定中心气流为主，适当发展边缘气流为辅。

4.7、设备管理：完善设备管理制度，严格落实设备定人定机；加强设备的点检润滑工作，确保集中润滑点位合格率100%；对设备运行状态进行研判并制定有效控制措施；检修周期结合设备运行情况利用短期休风做好周期及检修工作。

4.8、炉前出铁：严格执行操业中对出铁的要求，间隔时间:0-10min，每班（包括白班）出铁必须≥4炉（无任何条件严格执行），出铁时间大于两小时开另一铁口进行重叠，每天必须12-13炉。

4.9、加强工艺纪律检查：每周对影响高炉生产的因素进行检查、总结。

4.10、外部因素：减少外部因素待罐、待料等其他休慢风率，其次加强对INBA系统管理，避免因INBA系统故障造成高炉憋铁、慢风等情况。

探索成果：

C高炉完成了低硅冶炼攻关第一阶段、第二阶段的目标，具体目标成果如下:

第一阶段（8月27日-9月7日）为Si＜0.40%,命中率达到63.99%；

第二阶段（9月8日-9月18日）为Si＜0.40%,命中率达到71.65%；

五、高炉低硅冶炼攻关试验需求

5.1、杜绝无计划类休慢风（待罐、待料、外部因素）等；

5.2、做好设备定人定机管理及设备操、检、维、调工作，避免设备造成的休慢风；

5.3、焦炭需求：需保持稳定的用焦结构，保证入炉干熄焦比例≥85%，入炉干熄焦灰份＜12.5%，焦炭M40≥89，M10≤6.8，同时严格把控自产干熄焦质量波动。（焦化分厂负责）

5.4、矿石需求：需保证稳定的用矿结构，烧结比例控制在75%-80%，同时严格控制烧结矿质量及烧结碱度的波动、需稳定合适的炉料结构。（烧结分厂负责）

5.5、外围条件需求：物流保证高炉对罐准点率，避免因对罐晚点造成的高炉憋铁、慢风情况；（物流、总调负责）

5.6、因低硅操作，鱼雷罐需停加废钢，以保证炼钢的铁水温度；

5.7、因低硅冶炼，且高炉富氧要求大，造成高炉Tf需要靠加湿调整，需要协调能源中心保证蒸汽压力满足高炉加湿30g/m³。

5.8、洗炉需求：高炉需每周热洗炉一次，洗炉时硅约在0.60-0.70之间，热洗时间为1-2天。

六、C高炉低硅冶炼应急处置

6.1、当C高炉发生以下情况时停止低硅冶炼：

  6.1、因异外原因造成的休慢风，休慢风时间不能超过4小时，外部原因休慢风必须提前6小时通知，C高炉停止低硅冶炼采取增热措施。

6.2、高炉炉温连续2炉偏低，生铁成分出现高硅高硫时，高炉料速快，造成高炉顶温低，渣铁流动性差，渣温失常发黑，必须采取集中进行补焦措施，停止低硅冶炼。

6.3、入炉原燃料成分发生变化时，入炉干熄焦灰份＞12.5%，焦炭M40≤89，M10≥6.8，烧结矿碱度波动幅度超出±0.05，入炉焦炭结构发生变化调整，无法保证干熄焦配比≥85%时，停止低硅冶炼。

6.4、高炉冷却设备及介质发生漏水、风口小套发生漏水时，停止低硅冶炼。

6.5、高炉炉身静压每班大幅度波动2次以上，高炉压差透指高风量加不上去或高炉不接受风量，造成高炉长时间慢风操作，造成高炉频繁减风操作，高炉长时间无法维持正常风量，停止低硅冶炼。

6.6、高炉热负荷大幅度波动每班2次以上，造成高炉因热负荷波动大，炉温大幅下降，连续两炉及以上硅低于0.2，PT低于1470℃，停止低硅冶炼。

6.7、高炉班中因炉况波动静压透指急拐出现悬料现象，高炉大幅度减风坐料，造成高炉长时间低料线操作，停止低硅冶炼。

6.8、高炉班中因炉况波动出现2次以上管道大幅度减风时，因顶温高炉顶频繁打水，造成高炉H2含量升高，停止低硅冶炼。

6.9、高炉班中因炉况波动出现气流波动大，造成高炉煤气流分布不合理，煤气利用率大幅波动，停止低硅冶炼。

6.10、当高炉出现上述情况，造成高炉1天的评价打分在60以下或连续两天打分低于70分，炉况评价判定为顺行差，停止低硅冶炼。