Pyrolysis Effluent Quench and Separation for Endpoint Control
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Solution Overview
Problem
Conventional methods for controlling the endpoint of pyrolysis reactions are expensive, energy-intensive, environmentally undesirable, and prone to fouling due to the presence of reactive components, making it challenging to produce products suitable for petrochemical plants or oil refineries.
Innovation Solution
A system and method involving a pyrolysis reactor with a separation section that separates effluent into a heavy liquid byproduct stream and a vapor stream, using a stripping agent like steam to facilitate separation, and a fractionation section to cool and separate the vapor stream into a light gas and liquid product, with a recycle conduit for quenching and recycling heavy liquid byproducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fractionation methods are used to control endpoint, then product specifications for petrochemical plants are met, but energy consumption increases and fouling occurs
Solution Approach 1:
A quench stream is introduced as an intermediary substance to rapidly cool the pyrolysis effluent, preventing further reaction and controlling the endpoint. This quench stream acts as a mediator between the hot effluent and the fractionation section, allowing endpoint control without the high energy consumption of conventional fractionation methods
Solution Approach 2:
The effluent is quenched and cooled before entering the fractionation section, performing the cooling action in advance. This preliminary cooling reduces the temperature and energy content of the stream entering fractionation, thereby reducing overall energy consumption while maintaining endpoint control
2Manufacturing precision
If fractionation methods are used to control endpoint, then product specifications are met, but fouling occurs due to reactive components
Solution Approach 1:
The effluent undergoes preliminary quenching and cooling before entering the fractionation section. This preliminary action stabilizes reactive components like di-olefins and heavy waxy hydrocarbons by reducing their temperature and reactivity, preventing them from causing fouling in downstream equipment while still allowing endpoint control through subsequent fractionation
Solution Approach 2:
The quench stream serves as an intermediary that rapidly cools and stabilizes the effluent, preventing reactive components from polymerizing or decomposing in ways that would cause fouling. This intermediary cooling step protects downstream fractionation equipment from fouling while maintaining product quality
3Manufacturing precision
If conventional fractionation is used, then endpoint specification is achieved, but processing costs increase
Solution Approach 1:
The effluent is quenched and pre-cooled before fractionation, reducing the energy requirements and operational costs of the fractionation process. This preliminary preparation step lowers processing costs while still achieving the required endpoint specification through subsequent controlled fractionation
Solution Approach 2:
A portion of the heavy liquid byproduct is recycled back to the pyrolysis reactor as a quench stream. This feedback loop allows optimization of the process by using the byproduct itself to control the endpoint, reducing waste and lowering overall processing costs while maintaining specification compliance
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
Achieves controlled endpoint products suitable for petrochemical plants or oil refineries, reducing energy consumption and fouling risks while maintaining product quality.
Implementation Method 1
a separation section, having an inlet for the effluent stream of the pyrolysis reactor, wherein the separation section is configured to separate the effluent stream into a heavy liquid byproduct stream and a vapor stream
Implementation Method 2
the stripping agent is steam
Implementation Method 3
a compression and fractionation section in fluid connection with the separation section, wherein the fractionation section is configured to receive the vapor stream from the separation section, and further configured to cool and separate the vapor stream into a light gas stream and a liquid product
Implementation Method 4
the portion of the heavy liquid byproduct stream in the recycle conduit is configured to cool the effluent stream upstream of the inlet for the effluent stream into the separation section immediately after the effluent stream exits the pyrolysis reactor
Implementation Method 5
a pyrolysis reactor configured to perform a pyrolysis reaction on a plastic feed to produce an effluent stream
Data Source
AI summary
A system and method for controlling the endpoint of a product of a pyrolysis reactor is provided. The system can include a pyrolysis reactor, a quench system, a separation section, and a compression and fractionation section. In the system and method, a pyrolysis reactor performs a pyrolysis reaction on a plastic feed to produce an effluent stream, and the effluent stream is transferred to a separation section, wherein it is separated into a heavy liquid byproduct stream and a vapor stream. Portions of the heavy liquid byproduct stream can be recycled to the pyrolysis reactor or used to quench the effluent stream. A portion of the heavy liquid byproduct stream can also be withdrawn from the system as a secondary product. The vapor stream is transferred to a fractionation section, where it is cooled and separated into a light gas stream and a liquid product.