钢铁厂高能效利用副产煤气的可行途径

钢铁厂在生产过程中,副产了大量可燃煤气。副产煤气热值范围在3～20MJ/Nm3,所含的热量可被利用,如:电厂、焦炉、热风炉、热轧厂等所需燃料,可用副产煤气部分替代天然气,减少煤气放散,降低公司的能耗成本和环境污染。使用副产煤气虽能得益却也面临难题。副产煤气的产量和成分取决于生产和工艺状况,煤气用户必须随之调整其操作。用气设备的启停操作改变了煤气用量,造成煤气管网压力波动,副产煤气成分变化则会引起热值波动,一旦管网压力波动或成分改变,将对管网上用气单元的燃烧过程产生不利影响。针对副产煤气利用的复杂情况,AMB、AMEH和BFI公司开发了高能效利用副产煤气的途径,应用于部分钢铁厂,如:改善煤气管网压力和流量分布的技术,具备供需分布显示和预报功能的煤气管理系统。介绍了煤气管网压力波动控制以及副产煤气利用的结果和经验。

Realized measures for energy-efficient process gas use in metallurgical plants

During the production of high-quality steel products combustible process gases accrue as a by-product in metallurgical plants.The calorific value of these process gases varies between 3 and 20 MJ/m3 STP.The energy content of process gases can be used profitably,e.g.for partial substitution of natural gas in firing plants like power plant,cowper,coke oven or hot rolling mill.Thus the company’s energy costs are reduced and the environment pollution is decreased,since the process gases are not flared unused.Besides these advantages the use of the process gases is also connected with challenges.Amount and composition of the process gases are dependent on production and process conditions.Thus adjustments at the firing plants are necessary.Adaptation of production processes as well as connecting or switching off firing plants changes the volume flow of the process gases.This causes pressure fluctuations in the gas network.Additionally,changes in the process gas composition lead to fluctuations in the calorific value.As the firing plants are connected through a large gas network,pressure fluctuations or changes in the gas composition usually have negative effects on the combustion process within the attached plants.Thus the use of process gases is considerably sophisticated.AMB,AMEH and BFI have developed measures for the energy-efficient use of process gases.The measures have been realised at the participating metallurgical plants.e.g.the pressure and gas flow distribution in process gas networks have been improved and a gas management system with process gas production,consumption and prognosis functions has been developed.The obtained results and operational experiences of the control of pressure fluctuations in gas networks and of the energetically useful utilization of process gases in metallurgical plants are presented.