Comparison between MAT Flow Fixed Bed and Batch Fluidized Bed Reactors in the Evaluation of FCC Catalysts. 2. Naphtha Composition

Abstract

A comparison was performed between the performances of a MAT type reactor (flow fixed bed) and a CREC riser simulator reactor (batch fluidized bed) in the conversion of two VGO feedstocks (aromatic and paraffinic types) over three commercial equilibrium FCC catalysts, under similar conditions. In both units the reaction temperatures were 500 and 550 °C. The catalyst-to-oil relationships were from 2.3 to 6.2 (cumulative) and 6.2, and the times were from 15 to 40 s (time on stream) and from 5 to 30 s (reaction time) in the MAT reactor and the CREC riser simulator reactor, respectively. Results were compared in terms of the composition of the naphtha, in view of its contribution to the gasoline pool. Advantages were observed with data from the CREC riser simulator reactor, mainly derived from the fact that naphtha yields were, in general, closer to commercial values and showed a stable primary product behavior. Thus, they are easier to analyze as naphtha selectivities did not depend on the conversion reached. On the contrary, naphtha yields in the MAT reactor showed a maximum as a function of conversion. The comparison of the product distributions observed in the naphthas from each unit at the same conversion level showed that they can be very different; the naphtha obtained in the CREC riser simulator reactor was more paraffinic and less aromatic than the one obtained with the MAT reactor, and the proportions were similar to commercial values. Ranks of catalysts based on the various hydrocarbon fractions observed in the naphtha from each setup also differed in most of the cases. The differences in the results could be the consequence of notoriously different contact between reactants and catalyst and operative modes in each reactor, then impacting on the complex set of reactions occurring in FCC.

Catalyst/Feedstock Ratio Effect on FCC Using Different Catalysts Samples

“…Figure 6 reports that for 3 s, 5 s, and 7 s, there is a progressive increase of 1,3,5-TIPB conversion with temperature. These results are in line with the ones already reported in the technical literature by others [5,22,33,34] using the CREC riser simulator.…”

“…In 1992, an experimental device, invented by de Lasa [21] and designated as the CREC riser simulator, was used to simulate catalytic cracking [22,23]. This mini-fluidized CREC riser simulator reactor operates as a batch unit.…”

Production of Non-Conventional Fuels by Catalytic Cracking of Scrap Tires Pyrolysis Oil

“…32,33 The CREC riser simulator reactor allows for working at conditions (very short contact times, catalyst/oil ratio, porosity of the bed) similar to those of the industrial unit. [33][34][35]60,61 At zero time, the STPO is injected into the chamber where the catalyst is located turning into gas at once. A turbine located in the upper side of this chamber impels the feedstock ensuring a good catalyst-feed contact and well-mixed conditions.…”

“…It should be pointed out that a notorious effect of the properties of the catalysts has been also observed in the cracking of VGO, the conventional FCC feedstock, with equilibrated FCC catalysts. 58,60,61 This different behavior is mainly attributed to the hydrogen-transfer capacity of the catalysts.…”

A Hybrid FCC/HZSM-5 Catalyst for the Catalytic Cracking of a VGO/Bio-Oil Blend in FCC Conditions

“…The catalytic cracking runs of the VGO/bio-oil blend have been carried out in a CREC (Chemical Reactor Engineering Center) riser simulator (described in Scheme 1) designed to operate in a laboratory scale and in conditions that resemble those of an industrial FCC unit [40,41]. The experimental conditions were: temperature, 500-530-560 • C; contact time, 6 s; and catalyst/feed mass ratio (in a dry basis), 6 g cat g bio-oil −1 .…”