Lumping analysis for the methanol conversion to olefins kinetic model

The methanol to olefins reaction has been studied in a small scale fluidized bed reactor over a phosphorus modified ZSM-5 catalyst. The product distribution was relatively insensitive to either feed rate or inlet gas composition. It was more sensitive to temperature with a significant increase in light olefins when the temperature was increased from 400 to 550 °C. A model based on the hydrocarbon pool mechanism is proposed in which olefins form through reversible reactions with a high molecular weight hydrocarbon species in catalyst pores and intersections. Agreement between the model and the product distribution of the olefinic species is good throughout the temperature interval investigated. Further experimental work is required to adequately characterize the paraffin and C 6+ fractions.

Section: Methodsmentioning

confidence: 99%

Kinetic Modeling of Methanol-to-Olefin Reaction over ZSM-5 in Fluid Bed

Kaarsholm

Rafii

Joensen

et al. 2009

“…In a subsequent discussion, we shall combine real constituents of BL and their reactions into three classes and study their interrelations by using a well-known technique of lumping [see, for example, Coxson and Bischoff, 1987)]. Although accurate lumpability criteria and conditions have been developed for the linear systems (Wei and Kuo, 1969), in the case of nonlinear systems, such as the one presented here, the lumping procedure should heavily rely on the available chemical information about the system (Iordache et al, 1988).…”

Section: Construction Of a Modelmentioning

confidence: 99%

Kinetic model of soda black liquor oxidation under pressure

Nadezhdin¹,

Robertson²

1990

Soda black liquor is a complex chemical system containing various classes of organic and inorganic compounds dissolved in water at alkaline pH. Upon contact with oxygen under elevated temperature and pressure, a stagewise oxidative degradation of organics occurs. A simple model, based on a three-lump component, has been proposed in order to simulate the kinetic behavior of the original system in terms of total dissolved solids, chemical oxygen demand, and carbonate content of solution changes with time. Experimental data obtained in a series of batch and continuous autoclave runs have been closely approximated with three finite algebraic expressions containing two fixed reaction rate constants and one adjustable parameter.

“…For MTO processes, a certain amount of coke deposition on catalyst is known to favor light olefin selectivity, , which is quite different from fluid catalytic cracking (FCC) processes. Recently, the MTO catalyst and reaction kinetics have been extensively studied. − However, relatively few studies have investigated the simulation of MTO reactors, especially for large-scale reactors. Soundararajan et al suggested a core–annular fluid hydrodynamic model that combines an MTO kinetic model to describe the fluid hydrodynamics in a fast-fluidized bed riser.…”

Section: Introductionmentioning

confidence: 99%

Application of Filtered Model for Reacting Gas–Solid Flows and Optimization in a Large-Scale Methanol-to-Olefin Fluidized-Bed Reactor

Zhu

Luo

2016

A reactor model for a methanol-to-olefin (MTO) reaction system was constructed by incorporating a filtered drag model, a filtered gas−solid heat-transfer model, and an MTO kinetic model to probe large-scale reactor behavior and explore optimization. First, the efficiency of several typical gas−solid heat-transfer models and kinetic models was evaluated by comparing predicted results with experimental data. Second, the effect of two significant operation parameters, namely, reaction temperature and water-to-methanol ratio, were studied based on the above-mentioned model. Predictions suggested an optimum catalyst residence time (∼33 min) and an average coke content (∼6.74%) of this MTO system. In addition, relatively high temperature maximized ethylene production, and the water introduced into the feed significantly attenuated coke deposition. This work is the first to conduct coarse-grid simulations by using the developed effective filtered-CFD coupled model to probe the reaction flow and explore optimization for a large-scale MTO reactor.