PhD thesis, Chemical Engineering.
Current understanding and open questions concerning formation and motion of temperature fronts and patterns in packed-bed reactors and on single catalytic pellets are reviewed. For the single-reaction case, it is possible to readily predict the maximal temperature of fronts formed in packed-bed reactors following sudden changes in the feed conditions (wrong-way behavior) or during reverse-flow Cited by: The experimental measuremet of inter‐ and intraphase temperature gradients in a single pellet reactor for the Ni‐kieselguhr catalyzed benzene hydrogenation reaction is described. Experimental variables were temperature, feed composition, flow rate (hence heat and mass transfer coefficients) and intrinsic catalytic by: The complexity and challenges in noncontact temperature measurements inside microwave-heated catalytic reactors are presented in this paper. A custom-designed microwave cavity has been used to focus the microwave field on the catalyst and enable monitoring of the temperature field in 2D. A methodology to study the temperature distribution in the catalytic bed by using a thermal camera in Cited by: The reactor is designed to measure concentration profiles inside a single porous catalyst pellet in a defined flow and temperature field. Fig. 1 shows a sketch of the reactor. The reaction chamber has a width of 2 cm, a height of 2 cm and a length of 6 cm.
From comparative analysis of the pellet dimensions (as shown in Fig. 5a), pellet sizes with principal dimensions m m and m m were found to have high reaction performance and highest heat transfer rate for all the catalyst compositions, henceforth, temperature gradient is insignificant and negligible across the catalyst cross section. In conclusion, using temperature-dependent luminescence of NaYF4:Er,Yb crystallites, the temperature was probed over the course of a catalytic reaction at different heights in a reactor bed. The obtained results show a clear potential for luminescence thermometry for noninvasive in situ temperature measurements. Two tubular laboratory reactors, the single pellet string reactor (i.d. = cm) and the fixed bed reactor (i.d. = 5 cm) were compared on the basis of laboratory experiments of N 2 O catalytic decomposition and measurements of residence time distribution curves. K/Co 4 MnAlO x mixed oxide in the form of cylinders ( mm × mm) was used as a catalyst. This indicates that the electrical behaviour of the single pellet reactor (or packed bed reactors), does not conform to the idealised behaviour represented by the classical or partial discharging DBD parallelogram. The reason for this non-ideal behaviour is discussed further in sections –
For an arrangement with only surface-layered catalyst pellets in a reactor the maximum yield is 42%. However, the optimisation of pellet sizes in three different beds shows an increase of yield and it becomes 45%. For the effective control of temperature inside a reactor, the application of inert mixing and side stream distribution was applied. A single‐pellet reactor has been used to investigate the impact of partial external wetting on catalyst performance in a multiphase reaction system. The novel design simulates the local environment within a trickle‐bed reactor, and permits the direct measurement of . temperature and concentration profiles inside a reactor, reactor and pellet governing equations need to be solved simultaneously. With collocation method, we are able to obtain concentration and temperature profiles for the reactor successfully. Two important packed bed catalytic reactor behaviors concern us: “hotspot” and multiplicity. Contactless temperature measurements in a powder fixed bed, applied in CO 2 methanation. • Spatial temperature profiles at laboratory scale, under static and dynamic reaction conditions. • Impact of different fixed bed designs and dilution with inert material on heat removal. • In situ monitoring of deactivation of catalysts.