VOCs催化燃烧技术及其应用

对催化燃烧技术处理有机废气的基本原理、特点、工艺流程、燃烧动力学及其应用等进行了综述.     

微量有机化合物和一氧化碳催化燃烧反应器数学模拟

建立了废气中含有甲苯、一氧化碳、丙烯混合物催化燃烧反应器的数学模型.多组分混合物催化燃烧反应动力学模型采用吸附解离态的氧与吸附态的反应物反应的机理推导得到了反应速率方程.模拟计算了废气处理量、废气中各组分的浓度、床层入口温度对转化率的影响.     

VOCs催化燃烧技术

对催化燃烧技术处理有机废气的基本原理、特点以及催化剂、燃烧动力学、工艺流程和应用等研究进展进行了综述。     

催化燃烧技术处理石油化工企业含VOCs废气的工艺研究

石油化工企业工艺装置尾气及污水处理场逸散的废气均含有VOCs,其排放给区域空气质量和人体健康带来严重威胁。针对工艺尾气和污水处理场废气的特点,研究了催化燃烧工艺在处理这两类废气时工艺流程及控制方案。对工艺尾气采用碱洗—催化燃烧组合工艺,对污水处理场废气采用脱硫—均化—催化燃烧组合工艺。研究表明,针对上述两种废气,合理选择催化燃烧组合工艺及控制方案,能够有效处理废气中的VOCs组分,且处理后的气体烃类浓度均可达到国家有关标准。     

有机废气催化燃烧过程中多尺度效应和催化剂设计

有机废气是重要的空气污染物,基于负载型贵金属催化剂的催化燃烧技术因效率高、无二次污染等特点而被广泛研究和应用。但目前催化燃烧技术仍存在高耗能和高成本等缺点。有机废气多相催化燃烧效率均与催化剂一定尺度范围内的结构密切相关。在有机废气催化氧化反应体系内存在从活性中心到高性能催化剂与过程的多尺度效应。依据不同尺度范围内催化剂的功能,对催化剂进行相应的设计和功能强化,是提高催化剂净化效率的有效方式。总结了近年国内外研究者在有机废气催化燃烧贵金属催化剂不同尺度范围内的设计理念和效果,并对有机废气催化燃烧催化剂的未来发展方向进行展望。     

“活性炭吸附+催化燃烧”工艺在VOCs治理中的联合应用研究

本文研究了“活性炭吸附+催化燃烧”工艺在挥发性有机化合物（VOCs）治理中的联合应用,以提高现代化工废气处理系统的效率和环保性能。首先,详细介绍了该工艺的基本原理,包括活性炭吸附、脱附和催化燃烧的机理,以及影响催化燃烧反应的主要因素。随后,阐述了活性炭废气处理系统的主要处理工序与原理,包括废气的捕集、多级过滤、活性炭吸附和催化燃烧等阶段。在活性炭吸附+催化燃烧系统方案中,系统通过多级过滤确保废气在进入设备前达到清洁无害的标准。活性炭在吸附阶段通过其巨大表面积和微孔结构有效吸附废气中的有机物,将其转化为对人体无害的气体。随着活性炭吸附的饱和,通过吹扫干热空气进行脱附再生,维持活性炭床的吸附能力。脱附后的废气进入催化燃烧装置,在催化剂的作用下高效氧化燃烧,将有机物完全分解为水和二氧化碳。系统设计中,燃烧产生的热量被用于加热活性炭吸附系统和预处理废气,提高整个系统的能源利用率。     

有机废气催化燃烧过程中多尺度效应和催化剂设计

有机废气是重要的空气污染物,基于负载型贵金属催化剂的催化燃烧技术因效率高、无二次污染等特点而被广泛研究和应用。但目前催化燃烧技术仍存在高耗能和高成本等缺点。有机废气多相催化燃烧效率均与催化剂一定尺度范围内的结构密切相关。在有机废气催化氧化反应体系内存在从活性中心到高性能催化剂与过程的多尺度效应。依据不同尺度范围内催化剂的功能,对催化剂进行相应的设计和功能强化,是提高催化剂净化效率的有效方式。总结了近年国内外研究者在有机废气催化燃烧贵金属催化剂不同尺度范围内的设计理念和效果,并对有机废气催化燃烧催化剂的未来发展方向进行展望。     

石化污水场含烃废气催化燃烧降解研究

为消除石化污水场所逸散的烃类等有机挥发物对环境的危害,提出了采用浓度调整-吸附脱硫-催化燃烧组合工艺技术处理经封闭后有组织排放的废气的新工艺:用活性炭对废气总烃浓度进行调整,用Fe2O3吸附脱硫,用蜂窝状Pt、Pd、Ce多组分催化剂对废气进行催化燃烧。在中试研究的基础上,建立了一套3000m3/h的有机废气催化燃烧工业装置。工业试验结果表明,此组合工艺有机废气脱除率在95%以上,处理后的排放气可达到国家废气排放标准。     

汽车喷漆废气VOCs处理技术应用进展探究

汽车喷漆废气含有大量的漆雾和VOCs有机废气,是造成大气污染的主要原因之一。通过分析有机废气处理技术,针对汽车喷漆废气中VOC组分复杂问题和喷漆室、烘干室有机废气特点,研究了预处理+沸石浓缩转轮吸附+催化燃烧、预处理+活性炭纤维吸附+脱附+催化燃烧、预处理+生物滴滤+生物过滤的处理工艺等三种技术,以期为喷漆废气污染治理提供参考。     

VOCs废气处理用催化燃烧装置应用分析与研究

介绍了挥发性有机化合物(VOCs)废气处理用催化燃烧装置的结构与工作原理,并结合装置的应用实例来对催化燃烧设备进行分析与研究。根据现行相关大气标准的要求与实际工况,对催化燃烧装置在废气处理过程中所体现的优势与尚需改进之处进行了总结。     

丙烯腈尾气流向变换催化燃烧的实验研究

在固定床反应器中利用HPA型催化剂进行了丙烯腈尾气流向变换催化燃烧实验。考察了在不同尾气组成、不同空速及不同换向周期下流向变换催化燃烧反应系统的热波特性、可燃物的转化率等特性。结果表明,在广泛的操作条件变化范围内,可燃物的转化率均能维持在96％以上,即使空速、气体组成在一定范围内短期波动,流向变换催化燃烧反应系统仍然能够维持正常操作,但在可燃物浓度较低且空速、换向周期与可燃物浓度匹配不合理时反应系统将熄火,浓度较高时将飞温。     

1kW SOFC-CHP系统用催化燃烧耦合蒸汽重整反应器的实验研究

针对1 kW 固体氧化物燃料电池热电联供(SOFC-CHP)系统开发了集成催化燃烧、换热及蒸汽重整的反应器,搭建了性能评价系统,系统研究了燃烧侧气体组分及工艺参数对该反应器性能的影响规律。实验结果表明:在反应器燃烧侧气体入口温度为300℃、空燃比为10:1、电堆燃料利用率为65%、水碳比为3 的条件下,重整侧转化率达到73.6%,重整尾气中H₂ 含量为67.5%。电堆燃料利用率对重整反应转化效率影响较大,其值大于80%时,采用尾气燃烧的余热回收方式无法有效为蒸汽重整提供所需热量。在150~350℃范围内,降低燃烧侧气体入口温度对重整反应效率影响较小,建议采用尾气先换热再进行催化燃烧的流程设计,保证重整效率的前提下可有效提升系统热效率。空燃比的降低可小幅度提升重整效率,在保证电堆反应温度稳定的前提下,适当降低空燃比可减少空气压缩机的功耗,从而提升整个系统的效率。研究成果对SOFC-CHP 系统的优化和整体效率提升具有指导意义。     

Non-steady-state catalytic decontamination of waste gases

The non-steady-state behaviour of a fixed bed reactor controlled by periodical direction reversal of reactant feed, applied in catalytic oxidation of industrial waste gases, containing organic compounds and carbon monoxide, has been investigated. The effects of the type of oxidized compound, its initial feed concentration, linear gas velocity, inerts-to-catalyst ratio and inerts thermophysical characteristics on the formation of reactor concentration and temperature fields were elucidated. It was shown that autothermal reactor behaviour is guaranteed by concentrations of the oxidized component which ensure an adiabatic temperature increase in excess of 20 °C. Deviations of either flow rate or initial concentration of the oxidized compound do not disturb the operational stability.     

流向变换催化燃烧反应器的可操作性

在流向变换催化燃烧小型中试装置上利用国产催化剂进行了含混合芳烃模拟工业废气的净化试验,重点考察了挥发性有机物 (VOCs)能够通过调整换向周期在既不“飞温”也不“熄火”的条件下保持很高的VOCs转化率的浓度变化范围,初步观察了由于VOCs浓度过高或过低所引起的“飞温”或“熄火”过程.     

Enhanced model predictive control of a catalytic flow reversal reactor

The combustion of lean methane air mixtures in a catalytic flow reversal reactor (CFRR) is studied using a two dimensional heterogeneous continuum model, based on mole and energy balance equations for the solid (the inert and catalytic sections of the reactor) and the fluid phases. Following a design of experiments (DOE), many simulations were carried out to investigate the reactor performance. The results show the impact on the methane conversion and the maximum temperature in the reactor of key process parameters such as the methane inlet concentration, the superficial gas velocity, the switching time, and the mass extraction rate. A simple empirical model is deduced to predict the maximum temperature and conversion of methane in the reactor at stationary state. This model is combined with a model predictive control (MPC) strategy in the form of a terminal constraint to improve the controller performance. Results show that the control of the reactor is improved.     

Analysis of a fluidized bed membrane reactor for butane partial oxidation to maleic anhydride: 2D modelling

The partial oxidation of butane to maleic anhydride in a membrane reactor with improved heat transfer through the wall has been studied in this work. The reactor consisted of a catalytic fixed bed with sintered metal membrane wall that allows the gradual feed of air from the external fluidized bed. The influence of the most important design and operation variables (reactor length, gas flow rate, inlet temperature, butane inlet concentration, and air gas flow rate) on butane conversion and maleic anhydride selectivity has been studied by means of computer simulations using an experimentally-validated detailed 2D model. The performance of this reactor was systematically compared to the corresponding conventional fixed bed reactor. The membrane reactor has been found to provide slightly higher selectivity than the fixed bed reactor. Moreover, in the membrane reactor, the mixing of butane and air takes place through the wall directly inside the catalytic bed. Since solid beds avoid flame propagation, the process can be operated with higher butane inlet concentrations under safety conditions. Hence, the fluidized bed membrane reactor represents an interesting alternative for industrial-scale operation.     

乏风瓦斯流向变换催化燃烧试验研究

为实现低浓度瓦斯气体的高转化率,满足实际工程低温排气的要求,设计制作一套新型流向变换蓄热催化燃烧反应器,并利用模拟气体进行催化燃烧实验研究。结果表明,气体流量为70 L·min^-1、燃烧反应温度控制在500 ℃和甲烷体积分数为0.2%时,甲烷催化燃烧转化率超过80%,出口气体温度低于60 ℃。该系统能满足工程低温排气要求。     

Pt/Pd催化燃烧催化剂处理含苯系物废气技术研究

采用Pt/Pd催化燃烧催化剂对含苯系物的有机废气进行了处理.通过对单组分和多组分关键污染物模拟废气的催化燃烧考察实验表明,Pt/Pd催化剂对含苯系物有机废气中各关键污染组分具有较强的脱除效果.在反应器人口温度250℃,空速20 000 h-1的条件下,污染物去除率达到97％以上.净化后气体符合国家排放标准.     

Methanol synthesis in a forced unsteady-state reactor network

The feasibility of carrying out the low-pressure methanol-synthesis process in forced unsteady-state conditions, using a network of three catalytic fixed bed reactors with periodical change of the inlet position, has been investigated; advantages and limitations in comparison with the previously proposed reverse-flow reactor have been highlighted. The effect of the main operating parameters—inlet temperature, switching time, inlet flow rate—has been studied. A cyclic-steady-state condition and auto-thermal behaviour are possible; nevertheless, they are attainable only for switching times varying in two narrow ranges. Out of these regions, complex steady-states of high periodicity, where conversion is low, or extinction of the reactors occur. For low values of the switching time, the establishing of optimal temperature profiles along the network allows higher conversions than in the reverse flow reactor. Furthermore, the performances of the network are weakly affected by wash-out, the removal of unconverted gas in correspondence of switching, which is in intrinsic disadvantage of reverse flow operation.