基于加热炉热平衡的空燃比优化控制研究与应用

针对加热炉燃烧控制中存在的煤气热值不稳定问题,提出一种基于加热炉热平衡的燃烧空燃比控制方法,解决了燃料热值波动时空燃比难以自动修正的缺陷。实际生产应用表明,该方法能够较好地解决热值波动时的燃烧效率问题,合理地控制炉膛温度和炉气的含氧量,降低燃料消耗,改善控制钢坯的加热品质。     

空燃比动态寻优系统在加热炉上的应用

煤气热值及空燃比是影响加热炉能耗指标的重要因素之一。通过配置煤气热值仪及烟道残/定氧分析仪,在线、实时检测煤气热值和烟道残氧数值,并通过模型计算,合理、动态地配置空燃比,从而实现降低加热炉吨钢燃耗及氧化烧损率的目的。     

氧气高炉多区域约束性数学模型

将氧气高炉分为高温区、固体炉料区和煤气加热区三个区域,并分析了各区域的物理约束和化学约束条件.在物料平衡和能量平衡的基础上,建立了氧气高炉多区域约束性数学模型.理论分析和计算结果表明:多区域约束性数学模型可以弥补全炉热平衡的不足,反映热量在不同区域的利用价值;固体炉料区受间接还原反应和热平衡的约束,随着金属化率的升高,需要循环煤气量逐渐增大;当金属化率很高时,在高温区和固体炉料区满足热平衡条件下,虽然计算得到的燃料比很低,但煤气加热区煤气量不能实现平衡.     

煤压站混合煤气热值智能控制的实现

本文针对混合煤气热值波动对碳钢罩式炉生产的影响,提出了高、焦煤热值串级比值调节的控制方法,有效地实现了混合煤气压力、热值的双稳定,达到了良好的控制效果。     

Total Heat Exchange Factor Based on Non-Gray Radiation Properties of Gas in Reheating Furnace

Modified mathematical models based on imaginary plane zone method in reheating furnace were developed in which non-gray radiation properties of gas were considered,and the Newton's method and the finite difference method were adopted.Effects of productivity,fuel consumption,fuel-air ratio,calorific value of fuel and inserting depth of thermocouple on total heat exchange factor along the length of reheating furnace were investigated.The resuits show that total heat exchange factor increases with productivity or inserting depth of thermocouple,and it decreases when fuel consumption,fuel-air ratio or calorific value of fuel increases.The results are valuable for dynamical compensation of total heat exchange factor for online control mathematical models in reheating furnace.     

Russian electrometallurgy: Achievements,problems, prospects

The changes in the Russian metallurgy, in particular, electric furnace steelmaking, having occurred in the recent years are analyzed. The main increase in the steelmaking output is due to putting into operation of new electric furnaces in new miniworks and enterprises equipped earlier with open-hearth furnaces. Reaching the rated capacity of a furnace in Russia substantially lags behind foreign enterprises. Only 30–35% of the Russian market of corrosion-resistant steel are provided by Russian metal.     

鞍钢炼铁生产实现煤气置换的途径

在介绍了鞍钢炼铁生产热风炉使用煤气的现状以后,针对高热值焦炉煤气短缺、低热值高炉煤气过剩的实际情况,提出了要通过开发新技术,因地制宜,多种形式并举以实现多用或单一使用高炉煤气烧出高风温的置换焦炉煤气的可行方法和途径,文中还具体描述了高炉热风炉自身预热,荒煤气预热净煤气换热器,带有附加加热系统的回收热风炉烟气用换热器,以及对高炉煤气进行干式除尘等煤气置换措施。     

轧钢加热炉燃烧智能控制技术实践及节能减排分析

针对缺少煤气热值和废气氧含量在线检测,加热炉燃烧控制系统不能投入全自动的状况,采用模糊控制与专家系统结合对加热炉燃控系统智能化改造,使得加热炉燃烧控制得以优化,实现加热炉加热过程全自动控制,提高钢坯加热质量、降低氧化烧损、节约能源、减少碳排放。     

Techniques for quickly changing fuel gas in continuous annealing furnaces

An increasing number of annealing furnaces have recently been using cheaper and cleaner natural gas(NG)instead of liquefied petroleum gas(LPG)as fuel gas.However,the fuel gas of the furnaces often needs to be changed when NG supply is not adequate or when LPG becomes cheaper.Usually,changing the fuel gas involves changing various equipment as well as control parameters for instruments and the control system and hence is time consuming.Therefore,it is important to develop aquick process for changing fuel gas.This study discusses the techniques for quickly changing fuel gas in an annealing furnace.These techniques deal with the design of the pipe, valve and burner,the selection of the flow meter and the flow control valve,the switch of the software and parameters for the control system,as well as the operation,commissioning and hot test of the furnace when the fuel gas is changed.Using these techniques,it is possible to change fuel gas in6 h.     

优化M251S燃机燃烧、稳定机组运行

介绍了邯钢M251S燃机针对高炉煤气热值变化造成机组运行不稳问题的分析和处理。分别从燃料及热值的调节控制入手,减少了机组甩负荷的发生,保证了机组的安全稳定高效运行     

现代高炉高风温关键技术问题的认识与研究

提高风温可以有效降低高炉燃料消耗,促进高炉生产稳定顺行,是绿色低碳炼铁技术的重要发展方向之一。研究了热风炉热量传输过程和传热特性,通过传热学机理的研究解析,阐述热风炉加热面积与风温之间的关系,提出提高热流通量以改善热风炉传热的观点。研究了热风炉理论燃烧温度、拱顶温度和风温之间的关系,介绍了利用低热值高炉煤气和回收热风炉烟气余热,通过耦合预热和能量梯级利用的技术方法,实现高风温的技术创新及实践。提出了实现热风炉智能化操作的技术要素,论述了合理控制拱顶温度和抑制NO_x大量生成的工艺方法,以及有效预防热风炉炉壳晶间应力腐蚀的技术措施。指出实现低热值煤气的高效利用和高值转化,提高风温、降低燃料比和CO₂排放,是未来高炉炼铁的关键共性技术。     

双交叉限幅混合燃烧控制系统在CSP中的应用

以传统加热炉双交叉限幅燃烧控制系统为基础,考虑了现有系统在加热炉温度、煤气热值等因素大幅变化时响应速度慢、炉温超调严重等问题,提出了改进型双交叉限幅温度自动控制模型,有效解决了控制系统温度设定值变化、热值动态波动跟随性能差的缺点,具有控制灵活,响应速度快、适应性强等优点,通过现场应用证明,该方法能提高加热炉温度控制精度,降低系统燃料消耗,达到了节能环保的目的。     

Natural-gas heating of cupola furnaces for more energy-efficient iron production

Natural gas is employed to reduce coke consumption in cupola furnaces with an open or closed top. The usual approach here is combustion of the natural gas by means of burners in external chambers at the perimeter of the furnace housing. Depending on their design, the burners ensure partial or complete preliminary mixing of the gas and air, with an air excess of 1.2–1.5. Then the combustion products are sent directly to the batch bed. In this system, the coke consumption amounts to 8–9% of the metal charge, while the consumption of gaseous fuel is 30–40 m3/t of melt. In these conditions, the melt temperature rises slightly (by 10–20°C); the productivity is increased by 15–20%; and the harmful gas emissions (mainly CO) are reduced by 20–25%. The gas dynamics of the cupola furnace is periodically disrupted, with suspension of the batch bed, cooling of the melt produced, less complete chemical combustion, and damage to the furnace lining. When using this method, the gas–air mixture is supplied to the hot bed with an air excess no lower than 2.5–3.0. A high-temperature zone (1350–1380°C) of width 60–70 mm is formed and moves through the bed at a speed of 15–20 mm/min. This calls for uniform mixing of the gas and air, specific gas-dynamic conditions, and the creation of the required gas–air ratio, with an air excess of more than 2.5–3.0. If cold gas–air mixture is supplied to the furnace bed through a tuyere, the combustion zone divides the whole bed into two stages: the initial and final stages. The high temperature of the combustion zone ensures fast cooling of the material at ignition of the gas–air mixture. That prevents ignition in the space above the bed. The lack of direct contact between the high-temperature zone and the furnace’s working space improves the reliability and economic indices of this process (no heat losses). Bed combustion of natural gas in the heating of such cupola furnaces increases the productivity from 10 to 13.6 t/h (by 36%), with reduction in coke consumption by 80 kg/t (33.3%) and decrease in heat consumption by 25 kW (18.78%). The heat losses with the exhaust gases are reduced by 25.32 kW (16.2%). The total thermal efficiency of the system is increased from 35.58 to 42.26% (by 15.81%, rel.).     

室状加热炉烘炉过程数学模型及其数值模拟

以某公司拟建的高温蓄热式室状加热炉为研究对象，建立了烘炉过程传热数学模型。其中包括：炉膛热平衡数学模型、复合炉墙传热过程数学模型和废气温度计算模型等。并运用数值差分技术和四阶龙格一库塔法进行了数值注解，开发了计算机数值仿真软件包，对不同燃料量下的烘炉过程进行了优化计算。结果表明：对拟建的高温实验炉，为了保证在90分钟内使炉温达到所需的温度要求，其最佳煤气流量应该控制在70～90m^3／h。     

垃圾焚烧飞灰烧结处理新工艺及炉内气流特性研究

提出了一种处理垃圾焚烧飞灰的新工艺——低温固定床烧结处理工艺。相对于其他垃圾焚烧飞灰处理工艺而言,此工艺仅以煤为燃料,不需要消耗燃油、天然气等优质能源。配合处理能力为1 000 t/d的垃圾焚烧电厂,确定了一座飞灰烧结炉的主要参数,并对此烧结炉在不同风口数量、风口直径、鼓风速度、炉料粒径条件下炉内冷态的气流特性进行了数值模拟。结果表明:6个风口时,炉内的气流分布已经比较均匀;炉内竖直方向上的压降,受炉料粒径大小的影响较大。为了使炉料具有良好的透气性,炉料粒径以10～20 mm为宜。     

Making blast-furnace smelting more efficient through the injection of heated natural gas

Subjecting natural gas to multi-stage heating by passing it through the cooled cavities of certain tuyere elements instead of coolant water is technically simple to accomplish and makes it possible to heat the gas to 300°C or more, the exact temperature depending on the amount of gas used. The cost of instituting this technology is an order of magnitude lower than the savings realized by injecting heated natural gas into blast furnaces. The injection of heated natural gas into a blast furnace introduces additional heat into the furnace and makes it possible to use more natural gas in the smelting process without reducing the theoretical combustion temperature. It also increases the value of the coefficient that characterizes the replacement of coke by natural gas, since the gas undergoes more complete combustion in this case. Finally, the injection of heated natural gas results in a more uniform distribution of hydrogen across the furnace and allows fuller use of this element in the smelting operation.     

铁合金半密闭矿热炉高效余热回收方法的分析

以铁合金矿热炉为研究对象,考虑将半密闭矿热炉改造成全密闭型,避免半密闭型矿热炉的锅炉积灰、烟温低的缺点,同时由于全密闭型在生产过程中产生的是高热值煤气,有效解决半密闭矿热炉余热回收效率低的问题。结合实际两台31500kV·A硅锰矿热炉的案例,分析了半密闭矿热炉改造的位置、部件、设备以及改造后工艺操作的调整,并对比改造前后的矿热炉余热回收系统,探讨了余热回收效果以及投资效益等,为余热资源的回收、合理利用以及深度挖掘提供参考。     

转底炉直接还原工艺综合数学模型

为发展和深入认识转底炉直接还原工艺技术,建立了转底炉综合数学模型,该模型由转底炉本体热化学平衡、转底炉区域热平衡计算模型、余热回收模型、生球干燥模型、炉膛温度校核与尾气露点校核模型和转底炉流程模型组成.采用综合模型计算了该工艺流程的基本工艺参数.计算结果表明:煤气热值、废气排放温度和余热回收利用方案对整体能量消耗有不同程度影响,煤气发热值每增加50kJ·m^-3,理论燃烧温度提高22~25℃,煤气用量减少41~47m³·t^-1;空气预热温度平均每增加100℃,理论燃烧温度提高35~40℃,煤气用量减少90~103m³·t^-1.此外,应用此模型还可以计算任何原料和燃料等条件下的直接还原工艺参数,研究不同余热回收方案条件下的各个工艺参数的变化规律.     

阳极焙烧炉火焰系统的节能启动

针对阳极焙烧炉火焰系统传统的冷炉点火启动方法存在的不足,提出并应用了利用余热进行高温点火的节能启动方法。实践结果表明,该方法能有效缩短烘炉启动过程时间,大幅减少燃料消耗。