Fluidized Bed Reactor Coke Control Zone Baffles
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Solution Overview
Problem
Existing DMTO industrial devices struggle to fully utilize the advantages of new generation DMTO catalysts with higher methanol processing capacity and low-carbon olefin selectivity.
Innovation Solution
A fluidized bed reactor is designed with a coke control zone that allows for online modification of the DMTO catalyst by controlling coke content, distribution, and species, thereby enhancing catalyst performance and low-carbon olefin selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing DMTO industrial devices are used, then the device structure is simple and easy to operate, but the new generation DMTO catalyst with higher methanol processing capacity and low-carbon olefin selectivity cannot be fully utilized
Solution Approach 1:
The reactor is divided into multiple functional zones: reaction zone, coke control zone, spent catalyst zone, and gas-solid separation zone. The coke control zone is further segmented into n sub-coke control zones using baffles, allowing independent control of coke formation in different regions to optimize catalyst performance
Solution Approach 2:
A coke control zone is introduced as an intermediary section between the reaction zone and spent catalyst zone. This intermediate zone specifically controls coke content, distribution, and species on the catalyst through controlled residence time and reactant exposure, enabling the new generation catalyst to achieve higher methanol processing capacity and low-carbon olefin selectivity
2Reliability
If coke content in catalyst is increased to improve activity, then catalyst activity increases, but low-carbon olefin selectivity decreases due to wider coke content distribution
Solution Approach 1:
Different regions of the catalyst experience different coke accumulation conditions. The coke control zone creates localized high-coke environments that promote desired coke species (polymethylbenzene and polymethylnaphthalene) while preventing excessive coke on the main reaction catalyst, achieving both high activity and high selectivity through spatial differentiation of coke content
Solution Approach 2:
The system controls coke content, coke content distribution, and coke species by adjusting residence time in the coke control zone, temperature, and reactant composition. By optimizing these parameters, the catalyst achieves the optimal balance between coke content (for activity) and coke distribution (for selectivity)
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a narrow coke content distribution in the catalyst, leading to higher average activity and selectivity of low-carbon olefins, such as ethylene and propylene, while also controlling coke species to promote ethylene production.
Implementation Method 1
controlling the residence time distribution of the catalyst entering the coke control zone
Implementation Method 2
the catalyst flows in an annular shape in the coke control zone
Data Source
AI summary
A fluidized bed reactor, a device, and a method for producing low-carbon olefins from oxygen-containing compound are provided. The fluidized bed reactor includes a reactor shell, a reaction zone, a coke control zone and a delivery pipe, where there are n baffles arranged in the coke control zone, and the n baffles divide the coke control zone into n sub-coke control zones which include a first sub-coke control zone, a second sub-coke control zone, and an nth sub-coke control zone; at least one catalyst circulation hole is provided on each of the n-1 baffles, so that the catalyst flows in an annular shape in the coke control zone, where n is an integer. The device and method can be adapted to a new generation of DMTO catalyst, and the unit consumption of production ranges from 2.50 to 2.58 tons of methanol/ton of low-carbon olefins.