烧结烟气活性炭法自催化低温脱硝的基础研究

Sintering flue gas is the main source of NOx in the whole iron & steel industry. Though using activated carbon to purify sintering flue gas is promising, low flue gas temperature and huge gas volume lead to low denitration efficiency and high cost. According to the emission property of pollutants in flue gas, the idea of Fe2O3-rich ultrafine particles (Fe2O3-PM2.5) from flue gas selectively loaded into activated carbon as low-temperature catalyst for denitration is proposed in this program. Through investigating the behavior and action mechanism of activated carbon absorbing PM2.5, the distribution and loading property of Fe2O3-PM2.5 in activated carbon will be clarified, the catalytic denitration behavior and its anti-poisoning property of activated carbon supported Fe2O3-PM2.5 will be revealed, and the model of denitration reaction kinetics and autocatalytic denitration mechanism will be established, which address the problems of low denitration efficiency, high costs for preparation and load of traditional low-temperature catalysts. Hereby, methods to treat flue gas with high concentrations of SOx and NOx separately will be exploited. By regulating flue gas quality to realize the selective load of Fe2O3-PM2.5 and to restrain poisoning effect, the novel processes for removing NOx and SOx with parallel double-structured activated carbon towers and strengthening techniques for NOx removal will be designed, which will break through the problem of huge gas volume treated and high cost of traditional tandem towers, and will realize low-cost and efficient autocatalytic denitration. This program provides novel method to decrease NOx emission of sintering flue gas, which is of great significance to develop iron&steel industry in green manner.

烧结烟气是钢铁工业NOx的主要排放源，因其温度低、处理量大导致活性炭法脱硝效率低、成本高。本项目根据烧结烟气污染物的排放特征，提出将烟气中富含Fe2O3的超细颗粒物（简称Fe2O3-PM2.5）选择性负载到活性炭上作低温脱硝催化剂，通过研究活性炭吸附PM2.5的行为与作用机制，查明Fe2O3-PM2.5在活性炭中的分布和负载特性，揭示活性炭负载Fe2O3的催化脱硝行为和抗毒化性能，建立脱硝反应动力学模型和烧结烟气自催化脱硝机理，解决目前活性炭工艺脱硝率低、传统低温催化剂制备和负载成本高的难题；据此开发烧结高硫烟气和高硝烟气分流治理方法，调控脱硝烟气品质实现Fe2O3-PM2.5选择性负载和抑制毒化，构建并联式双塔活性炭脱硝脱硫新工艺和脱硝强化技术，突破现有串联式双塔工艺烟气治理量大、成本高的难题，实现低成本自催化高效脱硝。本项目为烧结烟气NOx减排提供了新方法，对钢铁绿色制造具有重要意义。

针对烧结烟气活性炭净化存在脱硝效率低的问题，开展基于烧结烟气PM2.5自催化的活性炭高效脱硝基础研究。围绕活性炭净化过程PM2.5的吸附行为，探明了活性炭吸附PM2.5对组成和结构的影响，明晰了不同组分PM2.5 (Fe、K、Na、Cl等)在活性炭中的分布规律，揭示了活性炭对不同粒级PM2.5的吸附机理，阐明了活性炭中FexOy-PM2.5、MCl-PM2.5的负载特性；进而探明了铁氧化物FexOy、氯化物MCl对活性炭脱硝的影响规律，明确了FexOy-PM2.5的催化作用及催化机理，揭示了MCl影响活性炭脱硝的作用机制及MCl的负载限值，建立了基于调控PM2.5吸附催化活性炭脱硝的原理。.围绕FexOy-PM2.5选择性负载的关键科学问题，查明了烧结不同阶段PM2.5、NOx、SO2等污染物的排放特征，揭示了FexOy-PM2.5的生成机理，提出高NOx、高FexOy-PM2.5烟气与高SO2、高MCl-PM2.5烟气分流治理的方法和原则，明确了基于烟气分流治理实现选择性负载FexOy并抑制MCl毒化作用的方法，开发了并联式双塔活性炭脱硝脱硫新工艺，并优化了脱硝工艺参数，实现了烧结烟气自催化活性炭低温脱硝，为烧结烟气NOx高效治理提供新的方法。在实验室的条件下，活性炭通过负载FexOy-PM2.5，其催化作用使脱硝效率由40%左右提高到70%，达到了较好的脱硝效果。.研究成果可为烧结烟气NOx的高效控制和超低排放提供技术支撑。出版烧结烟气污染物控制的专著1部，发表学术论文11篇，其中SCI 10篇，获授权国家发明专利8项，获湖南省科技进步二等奖1项，冶金科学技术一等奖1项、二等奖1项。