Reverse Flow Reactor With Reverse-Flow Feed Heat Recovery
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Solution Overview
Problem
Existing reverse flow reactors require large regeneration fluid flows, leading to increased compression costs, equipment sizes, and the number of reactors and valves, due to the limited heat capacity ratio between regeneration and product streams.
Innovation Solution
Implementing a reverse-flow feed cycle in combination with forward-flow and reverse-flow heating cycles to balance specific heat capacities, reducing the regeneration stream requirements and optimizing reactor volume and energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional reverse flow reactor uses a regeneration stream mainly composed of oxygen and nitrogen, then heat recuperation can be achieved, but the regeneration mass flow must be about 3 times larger than the product flow to achieve sufficient cooling due to the lower specific heat capacity
Solution Approach 1:
The invention changes the composition parameter of the regeneration stream by incorporating a significant portion of the product stream itself into the regeneration flow. This product-containing regeneration stream has a higher specific heat capacity than conventional air-based regeneration streams, enabling effective heat recuperation with reduced mass flow rates. The product stream composition (hydrocarbons) provides superior heat capacity compared to oxygen-nitrogen mixtures.
Solution Approach 2:
The product stream serves dual functions: it is both the desired output of the reaction and a component of the regeneration stream for heat recuperation. By routing a portion of the product stream back through the reactor in reverse flow to absorb heat from the regeneration gas, the system eliminates the need for separate cooling and regeneration streams, reducing overall mass flow requirements.
2Temperature
If a large regeneration flow is used to achieve sufficient cooling, then heat recuperation is effective, but the vessels must be larger and/or more numerous to avoid large pressure drops, increasing compression costs and equipment sizes
Solution Approach 1:
Changing the regeneration stream composition to include product stream components increases the specific heat capacity, which improves heat recuperation effectiveness without requiring increased reactor volume. The higher heat capacity per unit mass allows the same heat transfer duty to be accomplished with smaller equipment.
Solution Approach 2:
The invention uses the product stream itself as part of the regeneration medium, effectively copying the product's thermal properties to serve the regeneration function. This eliminates the need for separate large-volume equipment dedicated to regeneration, as the product stream performs both cooling and heat recovery functions.
3Temperature
If a large regeneration flow is used, then heat recuperation can be achieved, but compression costs increase due to the high mass flow requirements
Solution Approach 1:
The invention changes the specific heat capacity parameter of the regeneration stream by incorporating product stream components, which have higher heat capacity than conventional air-based streams. This parameter change reduces the mass flow rate required for effective heat recuperation, directly lowering compression energy requirements.
Solution Approach 2:
The product stream serves the dual purpose of being the desired output and providing thermal energy for regeneration. By using the product stream itself as part of the regeneration medium, the system eliminates the need for separate large-volume compression of dedicated regeneration gases, achieving self-service heat recovery that reduces overall compression energy consumption.
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 significantly reduces the need for larger reactors and compression, decreases flue gas production and CO formation, and lowers CO2 emissions while enhancing energy efficiency.
Implementation Method 1
the product stream can be heat exchanged with a regeneration stream of air and flue gas as a diluent to recuperate heat
Implementation Method 2
recuperate heat and supply the enthalpy for the chemical reaction
Implementation Method 3
the extent to which the product may be cooled in this way is limited by the ratio of regeneration flow to product flow, which is primarily determined by the heat capacity of the species in the streams
Implementation Method 4
recuperate heat and supply the enthalpy for the chemical reaction
Data Source
Figure 1(A)~1(C)
Figure 2
Figure 3(A)~3(C)
AI summary
A reverse flow reactor (RFR) and process having a forward reaction feed cycle, a reverse reaction feed cycle, and a reverse regeneration cycle. The heat convected in the forward feed cycle matches the heat convected in the reverse flow cycles. Compared to an RFR without the reverse feed cycle, the three-cycle RFR substantially reduces the regeneration air flow rate, associated compression requirements, and the overall reactor volume, that are required.