基于高温气冷堆的制氢耦合炼钢系统初步设计和能量分析

Preliminary design and energy analysis of a steelmaking system coupled with nuclear hydrogen based on a high-temperature gas-cooled reactor

高温气冷堆(high temperature gas-cooled reactor,HTGR)因其具有固有安全性和反应堆出口温度高的特点,在环境和能源领域拥有广阔的应用前景。HTGR不仅可以用于发电,还可以实现大规模制氢,而氢气可作为钢铁冶炼过程中的直接还原剂,有助于钢铁工业减少碳排放。该文提出了基于HTGR制氢的炼钢系统方案,包括反应堆、反应堆中间回路、制氢、发电和炼钢共5个子模块,并开展了多联产能源系统研究。其中,HTGR为制氢模块和发电模块提供热量,制氢模块产生的氢气作为还原剂和燃料进入竖炉(shaft furnace,SF)直接还原炼铁,制氢模块产生的氧气和发电模块产生的电供给电弧炉(electric arc furnace,EAF)炼钢。该文分析了碘硫循环效率、发电模块和制氢模块的功率比、直接还原铁(direct reduced iron,DRI)比例对系统产能的影响,以及系统的碳排放情况。结果表明:在发电模块与制氢模块功率比为1∶1,EAF直接还原铁占比为90%,碘硫循环制氢效率为37.8%的情况下,系统产钢率为45.6 t/h,每t钢可向电网输出1381.5 kW·h电能,同时CO_(2)的排放量仅为17.2 Nm^(3)。

[Objective]High-temperature gas-cooled reactors(HTGRs)have promising applications in the face of current environmental and energy problems due to their inherent safety and high reactor outlet temperature.They can be used not only for power generation but also for large-scale hydrogen production.Hydrogen can be used as a direct reducing agent in steelmaking,contributing to carbon reduction in the steel industry.It is necessary to study the coupling of HTGRs and the steelmaking system.[Methods]In this study,an HTGR-based steelmaking system is proposed,which includes five submodules:reactor module,reactor intermediate loop module,hydrogen production module,power generation module,and steelmaking module;then,a multi-generation energy system was investigated.In the reactor module,two HTGRs are connected in parallel as heat source,their thermal power is 250 MW,and the reactor outlet temperature is 950℃.The heat from the reactor module is transferred to the hydrogen generation module and the power generation module through an intermediate heat exchanger.The hydrogen generation module uses hydrothermal decomposition based on the iodine-sulfur process to generate hydrogen.The heat required for the iodine-sulfur process is provided by helium in the intermediate heat exchanger circuit and by the extracted steam from the power generation module.The hydrogen produced by the hydrogen production module is routed to a shaft furnace(SF)as the reductant and fuel for direct reduction ironmaking,and the oxygen produced by the hydrogen production module and the electricity produced by the power generation module are routed to an electric arc furnace(EAF)for steelmaking.The iodine-sulfur process efficiency.the power ratio of the power generation module to the reactor,the percentage of direct reduction iron in raw materials on the EAF system capacity,and the carbon emissions of the system are analyzed.[Results] In a steelmaking system with heat supplied by two 250 MW HTGRs,1.35 t of iron ore is required to produce l t of steel when the power ratio of the power generation module and the hydrogen generation module is l:1,the proportion of direct reduction iron in the raw material is 90%,and the iodine-sulfur process efficiency is 37.8%.Simultaneously,the system can deliver 63.0 MW(4.97 GJ for 1 t of steel)of electric energy to the power grid,and the steel production rate is 45.6 t/h.The parameter analysis shows that increasing the hydrogen production efficiency of the iodine-sulfur process can significantly increase the steel yield;however,the power consumption of the iodine-sulfur process module increases simultaneously,which reduces the output to the power grid.The steelmaking system proposed in this paper has very low CO_(2) emissions.When the proportion of directly reduced iron in the EAF is 90%,only 17.2Nm(33.8 kg)of CO_(2) is emitted in producing 1 t of steel.[Conclusions]Therefore,coupling the HTGR hydrogen production with the steelmaking system has great application potential for significantly reducing the CO_(2) emissions of the steelmaking industry and eliminating the dependence on coke.