Parallel Reactor Trains for Olefin Production
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Solution Overview
Problem
Current olefin synthesis processes face challenges in achieving continuous production with high olefin yields due to catalyst deactivation and the need for efficient separation and regeneration of reactor trains to prevent flammable gas mixtures, while maintaining low reaction pressures to optimize yields.
Innovation Solution
A multi-train plant design with parallel reactor trains, where one train is in regeneration mode and others in synthesis mode, utilizing heat recovery devices and quench zones to reduce pressure losses and separate regeneration and synthesis streams effectively, along with the use of shut-off devices and plate heat exchangers to manage pressure and prevent mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple reactor trains are operated in parallel with one in regeneration mode, then continuous olefin production is achieved, but the risk of flammable gas mixture formation increases due to potential mixing of regeneration and synthesis streams
Solution Approach 1:
The system divides the reactor trains into separate functional groups (regeneration mode vs. synthesis mode) with independent piping systems. Each reactor train has dedicated product lines that are segmented by function, preventing cross-contamination between oxygen-containing regeneration streams and hydrocarbon-containing synthesis streams, thereby eliminating the risk of flammable mixture formation while maintaining continuous production.
Solution Approach 2:
The patent introduces a shared compressor as an intermediary component that handles both regeneration and synthesis product streams separately through dedicated suction lines. The compressor acts as a controlled intermediary that processes streams independently before they could potentially mix, maintaining safety while enabling continuous operation across multiple reactor trains.
2Productivity
If reaction pressure is reduced to optimize olefin yields, then olefin production efficiency improves, but pressure losses in piping and equipment become more significant
Solution Approach 1:
The system performs preliminary cooling of product streams in quench zones before compression. By cooling the streams ahead of time, the gas volume is reduced, which minimizes pressure losses during subsequent transport and compression operations. This preliminary action allows the system to maintain low reaction pressures for optimal olefin yield while compensating for pressure losses through efficient pre-cooling design.
3Reliability
If reactor trains are separated into regeneration and synthesis modes, then catalyst deactivation is managed effectively, but the system complexity increases due to multiple shut-off devices and piping requirements
Solution Approach 1:
The patent designs the piping system and shut-off devices as universal components that serve multiple functions. The same infrastructure (compressor, piping network, control systems) handles both regeneration and synthesis streams through dedicated but structurally similar pathways. This multi-functional design manages catalyst deactivation effectively while avoiding unnecessary complexity through standardized, reusable component configurations.
4Loss of energy
If heat recovery devices are installed in each reactor train, then pressure losses are minimized, but the device complexity and investment costs increase
Solution Approach 1:
The system segments heat recovery devices into individual units for each reactor train rather than using a single centralized system. This segmentation allows each reactor train to independently optimize its pressure and temperature profile, minimizing pressure losses locally. The modular segmented approach manages the complexity through standardized repeatable units rather than a single complex centralized 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 design enables continuous olefin production with high yields by minimizing pressure losses, ensuring safe separation of streams, and maintaining low reaction pressures, thus enhancing propylene and ethylene production efficiency and safety.
Implementation Method 1
a heat recovery device for carrying out indirect heat exchange with the partial product stream coming from the reaction zone
Implementation Method 2
a first quench zone for carrying out direct heat exchange with the partial product stream coming from the heat recovery device and upstream of the connecting device
Implementation Method 3
rapidly cooling the reaction effluent stream to a temperature lower than the dew point temperature of the reaction effluent stream by direct injection of an aqueous liquid into the reaction effluent stream
Implementation Method 4
compressed by means of a compressor
Data Source
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AI summary
The invention relates to a multi-stage plant and a corresponding process for the production of olefins from oxygenates, in which several reactor trains, each comprising one or more catalyst-containing oxygenate-to-olefin (OTO) reaction zones, are arranged in parallel and operated in parallel, wherein at least one of the parallel reaction zones can be operated in a regeneration mode, while the OTO synthesis reaction can be carried out in parallel in the other reaction zones. The partial product streams obtained from the individual reactor trains operated in synthesis mode are discharged via partial product lines, combined into a total product line by means of a connecting device, compressed by means of a compressor, and separated into several olefin-containing hydrocarbon fractions by means of a multi-stage processing device.The inventive design of the plant and the process minimizes pressure losses and thus increases the yield of short-chain olefins, for example propylene.