高炉高球团比冶炼的煤气流流场与压力场数值模拟

SIMULATION OF GAS FLOW FIELD AND PRESSURE FIELD IN HIGH PELLET RATIO FURNACE SMELTING

在高炉生产冶炼中,提高球团矿比例会带来很多好处,如粒径均匀、SiO_(2)含量低于烧结矿、有利于间接还原、降低焦比和燃料比。然而,这也将导致软熔带透气性变差,高炉压差增大,同时抑制中心煤气流的发展,影响煤气流分布。本文利用数值模拟方法研究了提高球团比例时,某36003高炉内煤气流流场与压力场的变化。研究结果表明,当球团比例从31%提高至60%时,高炉总压差增大9.45 kPa。其中,高球团比促进了块状带空隙度的增加,使上部和中部压差减小,而软熔带对煤气流的阻力增加,导致下部压差显著增大,且增幅超过中部和上部压差降幅之和。同时,气体流速整体受到抑制,料层煤气流流速降低0.16 m/s,中心煤气流速降低0.32 m/s,而软熔带焦窗区域煤气流速降幅更大,为0.63 m/s。此外,若提高球团矿比例的同时保持压差不变,需要将入炉风量降低268 m 3/min,高炉下部压力降低,但中心煤气流被进一步抑制;或优化原料条件,调整布料制度,将块状带空隙度从0.329增大至0.337,此时煤气流流速仍降低,但块状带料层煤气流分布得到改善。

In blast furnace production and smelting,increasing the proportion of pellet ore can bring many benefits,such as uniform particle size,lower SiO 2 content than sintered ore,favorable indirect reduction,and reduced coke and fuel ratios.However,this will also lead to a decrease in the permeability of the melt zone,an increase in the pressure difference of the blast furnace,and at the same time suppress the development of the central gas flow,affecting the distribution of gas flow.This article uses numerical simulation methods to study the changes in gas flow field and pressure field in a 3600 m 3 blast furnace when increasing the proportion of pellets.The research results show that when the proportion of pellets increases from 31%to 60%,the total pressure difference of the blast furnace increases by 9.45 kPa.Among them,the high ball ratio promotes an increase in the porosity of the block shaped zone,reducing the pressure difference between the upper and middle parts,while the resistance of the soft melt zone to gas flow increases,resulting in a significant increase in the pressure difference at the lower part,and the increase exceeds the sum of the pressure difference decreases at the middle and upper parts.At the same time,the overall gas flow velocity was suppressed,with a decrease of 0.16 m/s in the gas flow velocity of the material layer and 0.32 m/s in the central gas flow velocity.The gas flow velocity in the coke window area of the soft melt zone decreased even more,at 0.63 m/s.In addition,if the proportion of pellet ore is increased while maintaining the same pressure difference,it is necessary to reduce the incoming air flow by 268 m 3/min,lower the pressure in the lower part of the blast furnace,but further suppress the central gas flow;Or optimize the raw material conditions,adjust the fabric system,and increase the porosity of the block belt from 0.329 to 0.337.At this time,the gas flow rate still decreases,but the gas flow distribution in the block belt layer is improved.