High-Pressure Pyrolysis Reactor with Thermal Mass for Ethylene Yield
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Solution Overview
Problem
Current ethylene production through pyrolysis processes faces challenges in achieving high yields while minimizing energy consumption and reducing by-product formation, particularly acetylene and coke, which increases energy demands and reactor pressure drops.
Innovation Solution
The process involves conducting pyrolysis at higher hydrocarbon partial pressures for a shorter duration in a reactor with thermal masses, allowing for efficient heat transfer and quenching, thereby shifting the equilibrium yield towards ethylene production and reducing compression energy needs for downstream separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pyrolysis is carried out at higher temperatures to increase ethylene yield, then ethylene production increases, but by-product formation (acetylene, coke) increases and energy consumption increases
Solution Approach 1:
The patent changes the pressure parameter from conventional low pressure to high pressure (up to 300 atm) and adjusts temperature parameters to optimize the pyrolysis reaction. This parameter change shifts the equilibrium toward ethylene while suppressing by-product formation through pressure-dependent reaction pathways
Solution Approach 2:
The patent employs periodic heating and cooling cycles in the pyrolysis process, using thermal masses to store and release heat. This periodic action allows the system to achieve high temperatures for ethylene production then rapidly cool to prevent over-cracking and by-product formation
2Manufacturing precision
If pyrolysis is carried out at lower pressures to reduce by-product formation, then selectivity to ethylene improves, but compression energy for downstream separation increases
Solution Approach 1:
The patent reverses the conventional pressure approach by operating at high pressures during pyrolysis. This high-pressure operation maintains high ethylene selectivity while the product is already at elevated pressure, significantly reducing the compression energy required for downstream separation and processing
3Object-generated harmful factors
If steam is added to reduce coke accumulation, then coke formation decreases, but energy consumption increases and partial pressure of hydrocarbon decreases
Solution Approach 1:
The patent extracts steam from the process by operating in its absence. By eliminating steam addition, the process avoids the associated energy consumption and maintains high hydrocarbon partial pressure, while using alternative methods (high pressure, periodic heating) to control coke formation
4Productivity
If residence time at high temperature is extended to increase conversion, then hydrocarbon conversion improves, but by-product formation increases
Solution Approach 1:
The patent uses periodic heating cycles with thermal masses to provide intense high-temperature exposure for short durations. This periodic action achieves high conversion during the heating phase then rapidly cools the system to halt further reaction, preventing by-product formation from extended residence time
Solution Approach 2:
The process rushes through the high-temperature zone quickly using intense periodic heating, achieving the necessary conversion in brief periods then immediately cooling. This skipping approach avoids prolonged exposure that would lead to by-product formation
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 enhances ethylene production efficiency, reduces energy consumption, and minimizes the formation of undesirable by-products like acetylene and coke, facilitating more effective separation of ethylene from similar boiling point compounds.
Implementation Method 1
heat being transferred from thermal mass located proximate to the first zone to the pyrolysis feed as the pyrolysis feed is passed through the reactor
Implementation Method 2
the pyrolysis feed can be passed through the thermal mass at a peak pyrolysis temperature in the range of from 850° C. to 1200° C. to convert at least 10.0 wt. % of the hydrocarbon in the pyrolysis feed into a pyrolysis product
Implementation Method 3
The pyrolysis product can be quenched by transferring heat from the pyrolysis product to thermal mass located proximate to the second zone to cool the pyrolysis product to a temperature below the peak pyrolysis temperature
Data Source
AI summary
The invention relates to a hydrocarbon conversion process and a reactor configured to carry out the hydrocarbon conversion process. The hydrocarbon conversion process is directed to increasing the overall equilibrium production of ethylene from typical pyrolysis reactions. The hydrocarbon conversion process can be carried out by exposing a hydrocarbon feed to a peak pyrolysis gas temperature in a reaction zone in the range of from 850° C. to 1200° C.