Liquid Phase Dispersion/Mixing Investigation in Gas-liquid Upflow Moving Bed Hydrotreater Reactor(MBR)

Abstract

Liquid phase dispersion/mixing studies have been performed for the first time on the catalyst bed of a cold flow scaled-down upflow moving bed re-actor (MBR) using residence time distribution (RTD) at various flow rates including the scaled down condition. MBR is hydrotreater and its design includes catalyst bed with conical bottom and plena. The catalyst bed is modeled using Wave Model, and its mixing parameters are estimated using a mathematical approach based on convolution and regression. A study is also shown to illustrate the limitation of Axial Dispersion Model (ADM) while modeling the flow which noticeably deviates from plug flow. In addition, a dimensionless variance is also estimated for the bed region from the RTDs. Overall liquid dispersion/mixing is seen high in MBR, with more disper-sion/mixing in the expanded bed region. Scaled down conditions are seen best when considering the overall catalyst utilization and liquid mixing for hydrotreatment.

Experimental Investigation of Liquid Holdup in a Co-Current Gas–Liquid Upflow Moving Packed Bed Reactor with Porous Catalyst Using Gamma-Ray Densitometry

“…We matched the Liquid Hourly Space Velocity (LHSV) to establish flow parameters and determine liquid flow rates, while gas flow rates were aligned with the industrial reactor's liquid-gas ratio. Detailed scaling procedures are discussed in V. Alexander's thesis [27]. The setup consists of a Plexiglas-packed bed column, a gas-supplying rotameter, a liquid cycling tank, and a pump.…”

“…This arrangement, along with the conical frustum in the cone section, is designed to provide a uniform upflow of phases into the catalyst bed and ensure stable bed operation. The design and photos of the internals are presented in Figure 1, and more details are given elsewhere [27]. The packed bed section, serving as the test area, is located above the cone section.…”

“…This nuanced response underlines the system's sensitivity to changes in flow conditions and underscores the utility of photon count data in assessing flow behavior and properties. More details on the signal analysis supported by raw data can be found elsewhere [24,27]. The GRD technique has been rigorously validated and calibrated against a precisely designed phantom, consisting of three acrylic glass columns with predetermined wall thicknesses.…”

“…pores + 𝜇𝜇 𝑙𝑙 𝜇𝜇 𝑙𝑙 𝑙𝑙 𝑙𝑙 𝑒𝑒𝑒𝑒𝑡𝑡. 𝑣𝑣𝑜𝑜𝑖𝑖𝑑𝑑 + 𝜇𝜇 𝑠𝑠 𝜇𝜇 𝑠𝑠 𝑙𝑙 𝑠𝑠 (27) where 𝑙𝑙 𝑠𝑠 = 𝜀𝜀 𝑠𝑠 𝜇𝜇, 𝑙𝑙 𝑙𝑙 𝑒𝑒𝑒𝑒𝑡𝑡.𝑣𝑣𝑜𝑜𝑖𝑖𝑑𝑑 = 𝜀𝜀 𝑙𝑙 𝜇𝜇, and the 𝜇𝜇 𝑠𝑠 𝜇𝜇 𝑠𝑠 𝑙𝑙 𝑠𝑠 𝑒𝑒𝑒𝑒𝑡𝑡.𝑣𝑣𝑜𝑜𝑖𝑖𝑑𝑑 gas is neglected.…”