一种用于处理有机废气的光催化反应器A photocatalytic reactor for treating organic waste gas
技术领域：本发明涉及一种气体净化装置，特别是一种处理难降解有机废气的净化装置。Technical field: The present invention relates to a gas purification device, especially a purification device for treating refractory organic waste gas.
背景技术：目前，已报道的用于处理废气的光催化反应器有固定床式和流化床式，其中以固定床光催化反应器居多。固定床光催化反应器中的光催化剂有颗粒状、蜂窝状和固定膜状，为了避免光催化剂粒子被气流带走，往往将粉末状催化剂填充在有一定厚度的床层反应器中，由于紫外光穿透催化剂床层能力有限，而使大部分催化剂不能利用，因此其光催化效果较差，而且由于催化剂床层中粒子往往是纳米级，填充紧密，其气阻较大；有的光催化剂以蜂窝状固定在光催化反应器中，虽然一定程度上减小了气阻，但也同样存在着大部分催化剂无法得到充分的紫外光照的问题；有的将光催化剂薄膜固定在反应器的内壁，既避免了颗粒状光催化剂被气流带走，又克服了大部分催化剂不能利用的缺陷，但设计中未考虑气流通过反应器出现短流的问题，短流问题在处理大流量气体时尤为严重，致使光催化降解效果不够理想。流化床光催化反应器是将颗粒状光催化剂在反应器中流态化，以提高气—固接触，但该种反应器也存在光利用率低的缺点，并且还有对催化剂磨损严重的问题。日本于1985年公布了RD81S型光催化空气净化器。该装置的催化床以片状环套在紫外灯管外，并和轴线呈一定的角度，床面与光束近于平行。由于光束不是垂直照射在催化剂膜面上，因此催化剂吸光效率较低，其催化活性相应不高，而且催化床的安装和催化剂更换不方便。1990年4月美国的Kawashima等设计了光催化空气净化器，其专利号为4,954,465，它存在气流路径长，处理量小，其结构过于复杂，不便于安装和维护的缺点；而且由于采用球形紫外光源和平板型催化床结构，紫外光能利用率低。1993年，李庆霖等推出了我国自有知识产权的光催化净化器的专利，其公告号为CN2114787U，其反应器内部结构采用了管式结构，并在光催化反应室前设置了活性碳吸附段，该反应器可用于处理低浓度的(＜10ppm)小分子物质(如NH3、H2S、CH3SH)，处理通量也较大(1.5M3/min)，处理效率较高，但对于难降解有机大分子物质(如苯系物)的去除主要依靠活性碳吸附段的吸附作用，光催化反应器对其去除的贡献不大，且长期使用存在着活性碳的再生和更换的问题。Background technology: At present, the reported photocatalytic reactors for treating waste gas include fixed bed type and fluidized bed type, among which fixed bed photocatalytic reactors are mostly used. The photocatalysts in the fixed bed photocatalytic reactor are granular, honeycomb and fixed film. In order to prevent the photocatalyst particles from being taken away by the airflow, the powdery catalyst is often filled in the bed reactor with a certain thickness. The ability of light to penetrate the catalyst bed is limited, so that most of the catalysts cannot be used, so the photocatalytic effect is poor, and because the particles in the catalyst bed are often nano-scale and packed tightly, the gas resistance is large; some photocatalysts Fixed in the photocatalytic reactor in a honeycomb shape, although the air resistance is reduced to a certain extent, there is also the problem that most catalysts cannot receive sufficient ultraviolet light; some photocatalyst films are fixed on the inner wall of the reactor , which not only avoids the granular photocatalyst being taken away by the airflow, but also overcomes the defects that most catalysts cannot be used, but the short-flow problem of the airflow passing through the reactor is not considered in the design, and the short-flow problem is especially serious when dealing with large-flow gases , resulting in an unsatisfactory photocatalytic degradation effect. The fluidized bed photocatalytic reactor is to fluidize the granular photocatalyst in the reactor to improve the gas-solid contact, but this kind of reactor also has the disadvantage of low light utilization rate, and there are serious problems of catalyst wear . Japan announced the RD81S photocatalytic air purifier in 1985. The catalytic bed of the device is surrounded by a sheet-shaped ring outside the ultraviolet lamp tube, and forms a certain angle with the axis, and the bed surface is nearly parallel to the light beam. Since the light beam is not irradiated vertically on the surface of the catalyst membrane, the light absorption efficiency of the catalyst is low, and its catalytic activity is correspondingly low, and the installation of the catalytic bed and the replacement of the catalyst are inconvenient. In April 1990, Kawashima and others in the United States designed a photocatalytic air purifier with a patent number of 4,954,465. It has a long airflow path, a small processing capacity, and its structure is too complicated to be easy to install and maintain; and due to the use of spherical ultraviolet Light source and flat catalytic bed structure, low utilization rate of ultraviolet light energy. In 1993, Li Qinglin and others released the patent of photocatalytic purifier with China's own intellectual property rights. The announcement number is CN2114787U. The internal structure of the reactor adopts a tubular structure, and an activated carbon adsorption section is set in front of the photocatalytic reaction chamber. , the reactor can be used to process low-concentration (<10ppm) small molecular substances (such as NH 3 , H 2 S, CH 3 SH), the processing flux is also large (1.5M 3 /min), and the processing efficiency is high. However, the removal of refractory organic macromolecules (such as benzene series) mainly depends on the adsorption of the activated carbon adsorption section, and the photocatalytic reactor does not contribute much to its removal, and there are problems with the regeneration and replacement of activated carbon in long-term use. question.
发明内容：本发明提供一种用于处理有机废气的光催化反应器，它解决了已有的同类产品存在的光能利用率低、催化活性低、催化器安装和催化剂更换不便的问题。本发明的光催化反应器包含有壳体1、设置在壳体1轴心位置的紫外灯管2、催化剂薄膜制成的隔片3、筒形的催化剂床4，至少两个催化剂床4设置在壳体1内，套装在紫外灯管2上的隔片3插在两个催化剂床4之间，在隔片3上开有使气体流通的缺口3-1，相邻的两隔片3上的缺口3-1相互错开。本发明由于紫外灯管2可以垂直照射在催化剂床4上，因而光能利用率较高。而套在紫外灯管2上的隔片3作为屏障，可以使气流在反应器内呈蛇形流动，使气流在轴向和径向不同位置催化薄膜制约下，充分撞击和接触催化剂薄膜，加强了气流与催化剂薄膜的接触效果，避免了气流短路，有利于催化剂活性的提高。本发明的光催化反应器主要用于封闭和半封闭人类生活空间(如：居室、卫生间、会议室、病房和娱乐场所)和工厂的生产车间、泵房中的有机废气的光催化消除。本发明的反应器内的催化剂床4是在不锈钢丝制成的环形支架4-1上固定有催化剂薄膜4-2而构成的，因此便于整体安装和更换。本发明的催化剂薄膜是以多孔金属网为载体，以掺铁二氧化钛作为催化剂，用溶胶——凝胶法制备而成，多孔金属网的孔隙率为85～95％。该催化剂薄膜可高效连续处理难降解有机废气(如苯系物、汽油等)，载体的多孔结构有效地扩大了催化剂的表面积，反应器内被处理气流与催化剂能更有效接触，因此对有机物废气能有效降解。此外，该光催化反应器具有气流通量大、易于安装和更换的优点。本发明针对目前已有的几种光催化反应器的结构形式的缺陷，进行了更加合理的设计和改进。隔片3和催化剂床4的径向定距插片式布置，使气流在反应器内蛇形流动，既加强了气流与催化剂床层的充分接触，有效地促进光催化反应，又可使反应器具有较大通量，较好的解决了气—固的良好接触(传质)和气阻间的矛盾。与目前所知的光催化反应器的专利相比，具有更合理的结构和更好的处理难降解大分子有机气体的效果。Summary of the invention: The present invention provides a photocatalytic reactor for treating organic waste gas, which solves the problems of low utilization rate of light energy, low catalytic activity, inconvenient installation of catalyst and replacement of catalyst existing in similar products. The photocatalytic reactor of the present invention includes a housing 1, an ultraviolet lamp 2 arranged at the axial center of the housing 1, a spacer 3 made of a catalyst film, and a cylindrical catalyst bed 4, at least two catalyst beds 4 are arranged In the housing 1, the spacer 3 sleeved on the ultraviolet lamp 2 is inserted between two catalyst beds 4, and a gap 3-1 for gas circulation is opened on the spacer 3, and the adjacent two spacers 3 The gaps 3-1 on the top are staggered from each other. In the present invention, since the ultraviolet lamp tube 2 can irradiate the catalyst bed 4 vertically, the light energy utilization rate is high. And the spacer 3 that is set on the ultraviolet lamp tube 2 acts as a barrier, which can make the airflow flow in a serpentine shape in the reactor, so that the airflow can fully hit and contact the catalyst film under the restriction of the catalytic film at different positions in the axial and radial directions, and strengthen The contact effect between the gas flow and the catalyst film is improved, the short circuit of the gas flow is avoided, and it is beneficial to the improvement of the catalyst activity. The photocatalytic reactor of the present invention is mainly used for photocatalytic elimination of organic waste gas in enclosed and semi-enclosed human living spaces (such as living rooms, toilets, conference rooms, wards and entertainment venues) and factory workshops and pump rooms. The catalyst bed 4 in the reactor of the present invention is formed by fixing a catalyst film 4-2 on an annular support 4-1 made of stainless steel wire, so it is convenient for overall installation and replacement. The catalyst thin film of the invention is prepared by a sol-gel method with porous metal mesh as a carrier and iron-doped titanium dioxide as a catalyst, and the porosity of the porous metal mesh is 85-95%. The catalyst film can efficiently and continuously treat refractory organic waste gas (such as benzene series, gasoline, etc.), the porous structure of the carrier effectively expands the surface area of the catalyst, and the gas stream to be treated in the reactor can contact the catalyst more effectively, so the organic waste gas can be effectively degraded. In addition, the photocatalytic reactor has the advantages of large air flow and easy installation and replacement. The invention aims at the defects of the structural forms of several existing photocatalytic reactors, and carries out a more reasonable design and improvement. The spacer 3 and the catalyst bed 4 are arranged in a radial fixed-distance insert type, so that the airflow flows in a serpentine shape in the reactor, which not only strengthens the full contact between the airflow and the catalyst bed, effectively promotes the photocatalytic reaction, but also makes the reaction The device has a large flux, which better solves the contradiction between good gas-solid contact (mass transfer) and air resistance. Compared with the currently known photocatalytic reactor patents, it has a more reasonable structure and a better effect of processing refractory macromolecular organic gases.
附图说明：图1是具体实施方式中光催化反应器的整体结构示意图，图2是图1的A-A剖视图，图3是多个催化床4的结构示意图，图4是图3的B-B剖视图。Description of drawings: Fig. 1 is a schematic diagram of the overall structure of a photocatalytic reactor in a specific embodiment, Fig. 2 is a sectional view of A-A of Fig. 1 , Fig. 3 is a schematic structural view of a plurality of catalytic beds 4, and Fig. 4 is a sectional view of B-B of Fig. 3 .
具体实施方式：本实施方式由壳体1、紫外灯管2、催化剂薄膜制成的隔片3、筒形的催化剂床4、混合器5和加湿器6组成，壳体1是在筒形壳1-1两端分别连接有封盖1-2而形成的，在两个封盖1-2上分别设有进气口1-3和出气口1-4。在进气口1-3的外端还连接有混合器5，混合器5内的支架5-1上安装有风机5-2，在混合器5的吸气口5-3的内侧还安装有加湿器6。混合器5将有机废气和水汽混合，以控制废气的相对湿度。紫外灯管2设置在壳体1的轴心位置。催化剂床4由环形支架4-1和催化剂薄膜4-2组成，环形支架4-1由左环4-3、右环4-4和使两环相连的直钢丝4-5组成，催化剂薄膜4-2缠固在环形支架4-1的外面。多个催化剂床4并排设置在壳体1内，其外表面紧贴壳体1的内壁，相邻的两个催化剂床4在一侧通过一个弧形丝7相连，使两催化剂床4之间形成一间隙。套装在紫外灯管2上的多个隔片3的边沿分别插在各催化剂床4之间的间隙内，缺口3-1开在隔片3的边部，相邻的两隔片3上的缺口3-1之间形成160°～180°的转角，最佳为180°。催化剂薄膜4-2和制成隔片3的催化剂薄膜均以多孔金属网为载体，以掺铁二氧化钛作为催化剂，用溶胶--凝胶法制备而成。多孔金属网的孔隙率为90％，所述掺铁二氧化钛是在二氧化钛中加入质量为0.06％～0.08％的铁盐，所述铁盐为硫酸铁或硝酸铁，掺铁二氧化钛可以提高催化剂的活性。在使用时也可以用二氧化钛作为催化剂。本实施方式所用的光源采用主波长为254nm的紫外灯，不仅有利于光催化反应，也可杀灭空气中的病毒和细菌。本发明所设计的光催化反应器的光源与混合器中风机的总功耗为25W。有机废气的处理量为0.5m3/min。用该光催化反应器对于含有苯、甲苯、二甲苯浓度为1000mg/m3的室内空气，在流量为0.5m3/min时，控制湿度为45％，经光催化处理反应器出口三种有机废气浓度均低于25mg/m3，低于国家标准(＜100mg/m3)，降解率大于95％。某泵房空气中的汽油气浓度为2300mg/m3，在流量为0.5m3/min时，控制湿度为60％，经光催化处理后反应器出口汽油气浓度低于50mg/m3，降解率超过97％。Specific embodiments: This embodiment is composed of a housing 1, an ultraviolet lamp tube 2, a spacer 3 made of a catalyst film, a cylindrical catalyst bed 4, a mixer 5 and a humidifier 6. The housing 1 is in a cylindrical shell The two ends of the 1-1 are respectively connected with the cover 1-2, and the two cover 1-2 are respectively provided with an air inlet 1-3 and an air outlet 1-4. Also be connected with mixer 5 at the outer end of air inlet 1-3, blower fan 5-2 is installed on the support 5-1 in the mixer 5, also be installed in the inboard of the suction port 5-3 of mixer 5 humidifier6. The mixer 5 mixes the organic waste gas and water vapor to control the relative humidity of the waste gas. The ultraviolet lamp tube 2 is arranged at the axial center of the casing 1 . Catalyst bed 4 is made up of ring support 4-1 and catalyst film 4-2, and ring support 4-1 is made up of left ring 4-3, right ring 4-4 and the straight steel wire 4-5 that makes two rings link together, and catalyst film 4 -2 is wrapped around the outside of the ring support 4-1. A plurality of catalyst beds 4 are arranged side by side in the shell 1, and its outer surface is close to the inner wall of the shell 1, and two adjacent catalyst beds 4 are connected by an arc-shaped wire 7 on one side, so that the gap between the two catalyst beds 4 A gap is formed. The edges of a plurality of spacers 3 set on the ultraviolet lamp tube 2 are respectively inserted in the gaps between the catalyst beds 4, the gaps 3-1 are opened at the edges of the spacers 3, and the adjacent two spacers 3 A rotation angle of 160° to 180° is formed between the notches 3-1, preferably 180°. Both the catalyst film 4-2 and the catalyst film made of the spacer 3 are prepared by a sol-gel method with porous metal mesh as a carrier and iron-doped titanium dioxide as a catalyst. The porosity of the expanded metal mesh is 90%. The iron-doped titanium dioxide is added with 0.06% to 0.08% iron salt by mass in the titanium dioxide. The iron salt is iron sulfate or iron nitrate. The iron-doped titanium dioxide can improve the activity of the catalyst . Titanium dioxide can also be used as a catalyst when used. The light source used in this embodiment is an ultraviolet lamp with a dominant wavelength of 254nm, which is not only beneficial to the photocatalytic reaction, but also can kill viruses and bacteria in the air. The total power consumption of the light source of the photocatalytic reactor designed in the present invention and the fan in the mixer is 25W. The treatment capacity of organic waste gas is 0.5m 3 /min. With this photocatalytic reactor, for indoor air containing benzene, toluene, and xylene with a concentration of 1000mg/ m3 , when the flow rate is 0.5m3 /min, the humidity is controlled at 45%, and the photocatalytic treatment of the three organic The exhaust gas concentration is all lower than 25mg/m 3 , lower than the national standard (<100mg/m 3 ), and the degradation rate is greater than 95%. The concentration of gasoline gas in the air of a certain pump room is 2300mg/m 3 . When the flow rate is 0.5m 3 /min, the humidity is controlled at 60%. After photocatalytic treatment, the concentration of gasoline gas at the outlet of the reactor is lower than 50mg/m 3 The rate is more than 97%.