何谓积碳 以含碳化合物为原料的催化反应的第一步通常是在催化剂表面上进行吸附形成含碳物种，如含碳物种经过分解、聚合等反应生成碳或焦炭沉积在催化剂表面，既所谓的积碳或结焦积碳会堵塞催化剂的活性位或催化剂的孔道，从而导致催化剂的失活！常发生积碳的催化反应 催化裂化 Pt重整 加氢精制 轻油制氢 积碳形态 积碳的形态一般分为无定形碳、层状石墨碳、管须状结晶碳以及粘稠状液态碳或焦油积碳原因 热裂解 催化裂解 深度脱氢 烯烃聚合 热裂解积碳是气相有机原料在高温下热裂解形成烟炱、焦油，它们在催化剂表面上生成有序的或无序的碳；催化积碳是在催化剂的作用下，烃类化合物发生催化积碳反应，它与催化剂的性质密切相关 氧化物、硫化物上主要是酸性积碳，积碳速率与催化剂的表面酸碱性有关； 金属上的积碳是通过烃类深度脱氢和脱氢环化聚合产生积碳，金属颗粒大小、分散度、合金化影响积碳； 金属负载酸性载体催化剂的催化积碳则两者同时存在 积碳防止 合金化，如Pt重整催化剂中添加第二组分金属形成合金，可减缓催化剂的积碳； 添加助剂，Pt重整催化剂采用少量Cl改性，可以减缓酸性积碳； 利用载体活性组分的相互作用，降低积碳； 对于酸性催化剂或载体，添加碱性助剂（K2O、MgO），减弱酸性积碳 通入水蒸气，消碳； 添加其他元素如稀土，加速消碳，防止积碳。
积碳失活再生——烧碳 催化剂因为积碳而失活，其催化剂再生通常采用烧碳的方法可以部分恢复催化剂的活性 烧碳条件如气氛、温度、气体组分等都会影响到再生后催化剂的结构、物化性质以及催化性能，因此必须严加控制几条注意事项（三步骤）：1. 除催化剂上的烃类和挥发物，必须在惰性气氛下进行； 2. 除去硫和轻质碳，必须在低温250-350度下先使金属氧化除去硫，同时某些聚合物和轻质碳也随之除去； 3. 最后除碳，根据碳的量以及类型在较高温度下进行 积碳表征催化剂积碳表征手段一览表表征手段具体介绍（1）Temperature-Programmed TechniquesTemperature-Programmed Oxidation (TPO)可获取信息： provides direct information regarding coke oxidation rate obtain useful information such as: location, composition (hydrogen/carbon ratio) and morphology (highly dispersed or multidimensional particles). 具体如： Determination of H/C Ratio Determination of Coke Location. Determination of Oxidation Kinetics Determination of Morphology Determination of Coke Amount 方法： detection of CO2 by a thermal conductivity detector (TCD) after it is separated from oxygen and water in a GC column; detection of CO, CO2 and hydrocarbonaceous compounds after methanation; quantification of CO2 with a mass spectrometer; monitoring temperature increment above a reference sample, in differentialthermal analysis (DTA) equipment; measurement of weight loss in thermal gravimetric analysis (TGA) equipment. detection of CO2 by FTIR Temperature-Programmed Hydrogenation (TPHy). 尤其适用于H2为反应物的催化反应——Characterization of coke by TPHy is of special interest when hydrogen is one of the reactants, 如： reforming, dehydrogenation methanol synthesis Fischer-Tropsch synthesis Temperature-Programmed Gasification与TPO相似，采用载气如He、Ar，也可以采用CO2代替O2（2）Electron MicroscopyThe localization, nature and structure of coke deposits have been examined with electron microscopy。
Typically, the electron microscopy alone does not provide much information, and is generally used in combination with related spectroscopies（3）Electron Energy Loss Spectrocopy (EELS)EELS能够提供的信息： provides analytical and structural information, similar to that given by X-ray absorption spectroscopy; detect the location of the coke（由于EELS具有高分辨率——1nm2）; provides qualitative information regarding the type of coke present on the catalyst（与参照样品对比）. 局限性：used only in few cases to characterize coke deposits on heterogeneus catalysts（4）Infrared Techniques (FTIR, DRIFTS)能够提供的信息： obtained with these techniques is the chemical identity of compounds that form the coke, such as olefinic, saturated or aromatic. information regarding the location of coke can be obtained by following the signal of certain catalyst surface groups, such as Bronsted OH. observe the deposition of carbonaceous materials on the working catalyst. 局限性： limited information on the nature of carbonaceous deposits because of their complexity and of the difficulty to assign unambiguously an IR band to particular species。
波数归属情况（5）Laser Raman SpectroscopyClassical Laser Raman Spectroscopy (LRS)提供信息：provide information regarding coke structure (pregraphitic or highly organized) and on the average dimension of the crystallite, as long as a monophasic carbon is produced优点： the high sensitivity that allows the analysis of catalysts with low coke content (0.3 — 0.5 wt%) the possibility of following the graphitization of amorphous carbon. 缺点： 结果解析困难； surface fluorescence干扰 UV-Raman Spectrometry (UV-RS). 解决了传统Raman的缺点（6）Dissolution of the Support and Solvent Extraction原理：after the dissolution of the support with a strong acid, the coke is extracted with different solvents，然后采用GC、MS等进行分析洗脱物。
缺点：the coke could be modified during this procedure常采用的溶剂（7）Neutron Scattering and Attenuation可提供信息：measure coke content and C/H ratio优点：This technique has the advantage that the coke content and therefore the coke profile along the catalyst bed, can be measured in-situ.（8）Nuclear Magnetic Resonance (NMR)提供信息： The NMR technique is a powerful technique to investigate the nature of carbonaceous deposits detect bindings between aromatic rings, alkyl fragments, and even tertiary carbenium ion-like species. 缺点：The information provided by NMR is not quantitative.种类： 13CCP/MAS – NMR. 1H NMR also used to study HY zeolites coked with n-heptane 129Xe NMR This technique has been used to study coke location on zeolite catalysts 29Si MAS N。