Moving Bed Reactor Phase Segregation via Stripping Gas
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Solution Overview
Problem
Conventional moving bed reactors face difficulties in managing co-current three-phase flow, leading to uneven distribution, reduced activity, and catalyst deactivation, particularly when transferring a three-phase flow from one reactor to another, which limits the control over contact time and uniformity of fluid-catalyst interaction during oxygenate conversion to distillate boiling range compounds.
Innovation Solution
A method and system involving a series of moving bed reactors with a feed distribution apparatus that allows for separate and controlled introduction of liquid and solid phases, using a stripping gas to separate phases, and maintaining catalyst activity through regeneration and controlled flow rates, enabling efficient conversion and oligomerization of oxygenates to distillate boiling range compounds without intermediate distillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional moving bed reactors are used to transfer three-phase flow, then catalyst regeneration is facilitated, but uneven distribution of flow phases occurs leading to reduced activity and increased catalyst deactivation
Solution Approach 1:
The reactor system is divided into multiple separate reactors arranged in series, with each reactor handling a specific phase flow (gas, liquid, or solid). This segmentation allows each reactor to be optimized for its specific phase while maintaining overall system functionality and catalyst regeneration capabilities.
Solution Approach 2:
A common catalyst circulation system acts as an intermediary between the separate phase-handling reactors, allowing catalyst to be regenerated and distributed uniformly across all reactors. This mediator enables coordinated operation of multiple reactors without requiring direct interaction between their phase streams.
2Device complexity
If conventional methods are used to transfer three-phase flow, then reactor operation is simplified, but independent control of input flow rate for each phase is limited
Solution Approach 1:
The system separates the three phase flows into distinct reactor streams, allowing independent flow rate control for each phase through separate control mechanisms. This segmentation provides precise control over gas, liquid, and solid phase flow rates without complicating the overall reactor operation.
3Reliability
If counter-current flow reactor is used, then three-phase flow management is improved, but residence time for contact between liquid and catalyst particles becomes relatively high
Solution Approach 1:
The reaction process is divided into multiple sequential reactor stages, each handling a specific phase. This segmentation allows for optimized contact times in each stage while maintaining overall efficient three-phase flow management through the series arrangement.
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 ensures uniform mixing and controlled contact time of phases, reducing catalyst deactivation and heat management issues, allowing for efficient conversion and oligomerization of oxygenates to distillate boiling range compounds with minimal temperature gradients and extended catalyst life.
Implementation Method 1
stripping the catalyst flow with a first stripping fluid to separate at least a portion of the first partially reacted effluent from the catalyst flow
Implementation Method 2
exposing a feed to the catalyst flow in the first moving bed reactor under first reaction conditions to form a first partially reacted effluent
Implementation Method 3
managing flow uniformity... substantially uniform mixing of the phases
Implementation Method 4
transfer of multiple phases between moving bed reactors
Data Source
AI summary
Systems and methods are provided for conversion of oxygenate feeds to distillate boiling range products using multiple moving bed reactor stages. The systems and methods allow for multiple stages to be used while avoiding the need for distillation or other boiling point based separation as the mixture of feed and effluent is passed between stages. Instead, a stripping gas is used to disengage the feed and effluent from the catalyst solids. In combination with an improved moving bed reactor design, this can allow substantially all of the feed and effluent from a first moving bed reactor stage to be passed into a second moving bed reactor stage, even when the feed and effluent include both vapor and liquid phase portions.