LPG Recovery from Reforming Effluent Using High-Temperature Absorption
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Solution Overview
Problem
Catalytic reforming of hydrocarbons produces valuable byproducts like hydrogen and LPG, but existing methods require costly equipment to efficiently recover these products, particularly C3 and C4 hydrocarbons, from the reforming-zone effluent.
Innovation Solution
A process involving multiple separation zones, including a first separation zone to form a net gas and liquid phase stream, followed by a second separation zone to enrich hydrogen, and an absorption zone to recover C3/C4 hydrocarbons using a cooled liquid phase stream, with optional membrane separation and PSA zones to optimize recovery without requiring expensive equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing methods are used to recover C3 and C4 hydrocarbons from reforming-zone effluent, then recovery effectiveness is improved, but equipment cost increases significantly
Solution Approach 1:
The patent changes the operating parameters of the absorption zone by utilizing the inherent temperature of the reforming effluent (typically 300-500°C) directly in the absorption process, eliminating the need for costly chillers and vapor driers that would be required to cool the gas stream to ambient temperatures. This parameter change maintains high recovery effectiveness while dramatically reducing equipment cost.
Solution Approach 2:
The patent extracts and utilizes the thermal energy from the reforming effluent stream itself as the heating source for the absorption process, removing the need for external cooling equipment. By taking out the heat recovery function from the overall system and using it to drive the absorption process, the patent eliminates expensive cooling infrastructure while maintaining effective C3/C4 hydrocarbon recovery.
2Ease of manufacture
If high temperature operation is used in the absorption zone, then equipment cost is reduced, but process control complexity increases
Solution Approach 1:
The patent merges the heat recovery function with the absorption function by using the hot reforming effluent directly as both the heat source and the absorbing medium. This combination eliminates the need for separate cooling and absorption units, reducing overall process control complexity despite the high temperature operation. The thermal and mass transfer processes are integrated into a single unified operation.
Solution Approach 2:
The reforming effluent serves itself by providing both the thermal energy required for the absorption process and the absorbing medium for C3/C4 hydrocarbon recovery. The hot gas stream automatically provides the necessary heat without requiring external heating equipment, and the liquid phase components naturally absorb the lighter hydrocarbons. This self-service approach simplifies process control by eliminating multiple independent control systems.
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 process effectively recovers C3/C4 hydrocarbons and hydrogen from the reforming-zone effluent at lower operational costs by utilizing higher temperatures in the absorption zone and optimizing pressure and temperature conditions, reducing the need for costly chillers and vapor driers.
Implementation Method 1
absorbing C3/C4 hydrocarbons from the cooled gas stream with the cooled liquid phase hydrocarbon stream in an absorbing zone to form a fuel gas stream and a C3/C4 enriched liquid phase hydrocarbon stream
Data Source
AI summary
Embodiments of apparatuses and methods for reforming of hydrocarbons including recovery of products are provided. In one example, a method comprises separating a reforming-zone effluent into a net gas phase stream and a liquid phase hydrocarbon stream. The net gas phase stream is separated for forming an H2-rich stream and a first liquid phase hydrocarbon stream. The H2-rich stream may be contacted with an adsorbent to form an H2-ultra rich stream and a gas stream. C3/C4 hydrocarbons are absorbed from the gas stream with the liquid phase hydrocarbon stream. The gas stream may be contacted with an H2/hydrocarbon separation membrane to separate the PSA tail gas stream and form an H2-rich permeate stream and an H2 depleted non-permeate residue stream.