Reactor Cooling via Atomized DME Spray for Olefin Production
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Solution Overview
Problem
Existing reactors for producing C2- to C8-olefins, such as propylene, face challenges with non-isothermal reactions and complex cooling designs, which complicate the process and reduce efficiency.
Innovation Solution
The reactor design features trays with molecular-sieve catalysts and an atomizer system that sprays a liquid phase containing DME and MeOH between reaction stages, ensuring quasi-isothermal conditions and efficient catalyst utilization by adjusting the temperature and material flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat exchangers are arranged between reaction stages to cool the reaction mixture, then the reaction temperature can be controlled, but the device design becomes elaborate and fluidic conditions become unfavorable
Solution Approach 1:
The patent introduces a cooling medium as an intermediary substance that flows through channels in the tray structure to absorb heat from the reaction mixture. This mediator approach replaces complex external heat exchangers with a simpler integrated cooling system where the cooling medium transfers thermal energy from the catalyst layer to the tray walls, thereby controlling reaction temperature without elaborate cooling equipment
Solution Approach 2:
The cooling function is merged with the tray structure itself. The trays that support the catalyst layers also serve as heat transfer surfaces through which cooling media flow. This integration combines the mechanical support function with the thermal management function, eliminating the need for separate elaborate cooling systems and improving fluidic conditions by removing complex heat exchanger components from the reaction path
2Productivity
If a thick layer of catalyst is used in each reaction stage, then conversion efficiency improves, but temperature control becomes difficult and catalyst introduction becomes complex
Solution Approach 1:
The catalyst layer is segmented into multiple thinner layers distributed across several reaction stages, with each stage having its own tray-supported catalyst layer. This segmentation allows better temperature control in each layer while maintaining overall high conversion efficiency through the series arrangement. The cooling channels in each tray manage heat in discrete segments rather than dealing with one large thick catalyst bed
Solution Approach 2:
The trays with integrated cooling channels are prepared in advance with predetermined cooling pathways before catalyst loading. This preliminary preparation of the cooling infrastructure simplifies subsequent catalyst introduction, as the cooling system is already in place to manage the exothermic reactions from the start, avoiding complex simultaneous installation of cooling and catalyst systems
3Volume of moving object
If multiple reaction stages are arranged vertically, then space utilization improves, but temperature distribution becomes non-uniform and cooling becomes complex
Solution Approach 1:
Each reaction stage in the vertical arrangement is equipped with its own locally-integrated cooling channels in the tray structure, providing localized temperature control tailored to the specific thermal conditions of each stage. This local quality approach ensures uniform temperature distribution across all vertical stages by addressing thermal management independently at each location rather than relying on a centralized complex cooling system
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
This approach maintains a consistent reaction temperature, simplifies catalyst introduction, and enhances flow efficiency, leading to improved process control and productivity.
Implementation Method 1
By atomizing the liquid phase, the temperature of the reaction mixture leaving the reaction stage at a temperature of 400 to 500° C. is reduced to a level of 380 to 470° C.
Implementation Method 2
an atomizer system composed of an assembly of nozzle tubes, the interspace of which is in each case delimited above and below by two adjacent reaction stages, designed to evenly spray a liquid phase containing DME and/or MeOH
Implementation Method 3
each of such stages being composed of a tray carrying a fixed-bed zone formed by a packing of granular molecular-sieve catalyst
Data Source
AI summary
A reactor is described for the production of C2 to C8 olefins from gaseous oxygenate and H2O and one or more material flows containing C2 C4, C5, C6, C7, C8 olefin and paraffin at 400° to 470° C., wherein several reaction stages which the material flow can pass through from the top to the bottom, each consisting of a support base with a catalyst layer situated on it, are arranged in a closed, upright container. In order to be able in each case to lower the temperature of the reaction mixture leaving the reaction stages before it enters into the next reaction stage, it is provided that each support base consists of cells which are placed closely next to each other with no gaps and which are securely attached to each other and filled with catalyst, and in the space formed by two neighboring reaction stages, respectively, an assembly of nozzle tubes is installed for spraying a liquid phase containing H2O and DME and/or MEOH, using a water-saturated gas phase containing mainly DME and/or MEOH, in the direction of the following reaction stage downstream.