Circulating Fluid Cooling for Dehydrogenation Effluent
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Solution Overview
Problem
Catalytic dehydrogenation processes face issues with fouling of heat exchange units due to heavy hydrocarbon compounds, leading to reduced cooling capacity and increased pressure drops, which decrease olefin production yields and require additional energy for compression.
Innovation Solution
A process involving a circulating fluid stream to cool and compress reactor effluent streams, recovering thermal energy through indirect heat exchange, which reduces fouling and pressure drops, and utilizes the recovered energy to enhance olefin production and reduce external energy inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If indirect heat exchange units are used to cool dehydrogenation reactor effluent streams, then cooling capacity is provided, but fouling occurs due to heavy hydrocarbon condensation
Solution Approach 1:
The patent introduces a cooling medium that acts as an intermediary substance to absorb heavy hydrocarbons from the effluent stream during the cooling process. This mediator prevents the heavy hydrocarbons from condensing and fouling the heat exchange surfaces, while still achieving the required cooling effect. The cooling medium circulates through the heat exchange unit, capturing contaminants and allowing the effluent to be cooled without direct contact that would cause fouling.
2Productivity
If cooling capacity is reduced due to fouling, then less maintenance is needed, but compression capacity and productivity decrease
Solution Approach 1:
The patent implements a feedback mechanism where the cooling medium continuously circulates and absorbs heavy hydrocarbons that would otherwise cause fouling. By monitoring and maintaining the cooling medium's ability to absorb contaminants, the system prevents fouling before it occurs, ensuring consistent cooling capacity and compression performance. This feedback loop maintains optimal operating conditions without requiring frequent shutdowns for cleaning.
3Loss of energy
If pressure drop across heat exchange unit is reduced, then energy consumption decreases, but cooling effectiveness may be compromised
Solution Approach 1:
The patent employs a hydraulic or pneumatic cooling system where a cooling medium (gas or liquid) is used to cool the effluent stream. This approach minimizes pressure drop compared to traditional mechanical cooling methods, reducing the energy required for subsequent compression. The cooling medium flows through the effluent stream or across heat exchange surfaces designed to maintain low pressure differential while achieving effective cooling through the phase change or heat transfer properties of the cooling medium.
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 increases olefin yields, minimizes fouling and pressure drops, and reduces energy consumption by utilizing recovered thermal energy, thereby improving the efficiency and economics of the dehydrogenation process.
Implementation Method 1
contacting the reactor effluent stream with a circulating fluid stream in a first contact cooling zone wherein the reactor effluent stream is cooled
Implementation Method 2
Thermal energy is subsequently recovered from the first heated circulating fluid stream via indirect heat exchange with a first process stream in a first heat exchange zone
Data Source
AI summary
A processing scheme and arrangement for enhanced olefin production involves recovering thermal energy from a reactor effluent stream resulting from the dehydrogenation of a dehydrogenatable hydrocarbon. The process involves contacting the reactor effluent stream with a circulating fluid stream in a first contact cooling zone to produce a product stream and to form a heated circulating fluid stream. Thermal energy is recovered from the heated circulating fluid stream via indirect heat exchange with a first process stream in a first heat exchange zone to form a cooled circulating fluid stream. The cooled circulating fluid stream can be subsequently cooled and at least a first portion thereof returned to the first contact cooling zone.