河北冶金

针对部分钢厂应用烧结烟气循环工艺后效果不佳进而闲置问题进行了研究。通过类似烧结项目烟气成分检测，寻找烧结机各风箱烟气温度、流量和烟气成分的分布规律，而后以氧含量和温度为主要约束条件，进行风氧平衡计算，最终确定头部1#～3#风箱和尾部18#～21#风箱烟气参与循环，其中尾部4个风箱先经过余热锅炉回收高温余热，实现烟气余热梯级利用；另外，将环冷机三段、四段、五段烟囱和风机串级连接，烟气汇入烟气循环系统，环冷机实现近零排放。环冷热风与内循环烟气混合后，接入烟气循环罩，重新参与烧结过程。烟气通过风量平衡计算，保证循环烟气罩内15～30 Pa的微负压。在内循环风机出口设置富氧装置，使得进入料面的氧含量控制在20%左右，保证烧结矿品质。项目投产后，一方面有效提升了烧结矿的产量和质量，减少废气排放量，降低了对环境的污染；另一方面，能够将废气中的热能梯级利用，提高废热利用率，避免了能源的浪费，实现了节能降耗的目标；具有良好的经济效益和社会效益。

A study was conducted on the problem of idle sintering flue gas recirculation processes in some steel plants due to poor application effects. Through flue gas composition detection of similar sintering projects, the distribution laws of flue gas temperature, flow rate and composition in each wind box of the sintering machine were identified. Then, with oxygen content and temperature as the main constraints, the air-oxygen balance calculation was carried out, and it was finally determined that the flue gas from the No.1 to No.3 wind boxes at the head and the No.18 to No.21 wind boxes at the tail participate in the recirculation. Among them, the flue gas from the four tail wind boxes first passes through the waste heat boiler to recover high-temperature waste heat, achieving the cascade utilization of flue gas waste heat. In addition, the chimneys and fans of the third, fourth and fifth sections of the circular cooler are connected in series, and the flue gas is integrated into the flue gas recirculation system, realizing near-zero emission of the circular cooler. The hot air from the circular cooler is mixed with the internal circulation flue gas and then connected to the flue gas recirculation hood to re-participate in the sintering process. Air volume balance calculation is performed on the flue gas to ensure a slight negative pressure of 15 to 30 Pa inside the recirculation hood. An oxygen enrichment device is installed at the outlet of the internal circulation fan, which controls the oxygen content entering the material surface at about 20% and ensures the quality of sinter ore. After the project is put into operation, on the one hand, it effectively improves the output and quality of sinter ore, reduces exhaust gas emissions and mitigates environmental pollution. On the other hand, it enables the cascade utilization of thermal energy in the exhaust gas, raises the waste heat utilization rate, avoids energy waste and achieves the goal of energy conservation and consumption reduction, yielding remarkable economic and social benefits.