Cyclopentadiene Production via C1-C4 Co-feedstock Pressurization
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Solution Overview
Problem
Current processes for producing cyclopentadiene (CPD) and dicyclopentadiene (DCPD) face challenges such as low yield, high impurity levels, and equipment damage due to air and oxygen ingress, along with thermodynamic equilibrium constraints that suppress conversion of acyclic C5 hydrocarbons to CPD, especially when operating at sub-atmospheric pressures.
Innovation Solution
A process involving the catalytic conversion of acyclic C5 hydrocarbons with a C1-C4 hydrocarbon co-feedstock to increase reactor outlet pressure above atmospheric levels, minimizing air and oxygen ingress, while maintaining low partial pressures of CPD and hydrogen, and an effective separation process to minimize Diels-Alder reactions, allowing for high-yield production of CPD and high-purity DCPD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acyclic C5 hydrocarbons are converted to CPD under thermodynamic equilibrium conditions, then CPD production is suppressed, but if conversion conditions are intensified (high temperature), then cracking of C5 hydrocarbons occurs
Solution Approach 1:
The process is divided into two distinct stages: (1) catalytic conversion stage where acyclic C5 hydrocarbons are converted to CPD at controlled conditions, and (2) separation stage where CPD is rapidly separated from the reaction mixture. This segmentation allows the conversion to proceed without reaching thermodynamic equilibrium that would suppress CPD formation, while avoiding prolonged exposure to high temperatures that cause cracking.
Solution Approach 2:
The patent applies preliminary action by rapidly cooling and separating CPD immediately after formation from the catalytic conversion. This preliminary separation prevents the system from reaching thermodynamic equilibrium and avoids subsequent cracking reactions, effectively locking in the CPD yield achieved during the brief conversion period.
2Productivity
If reactor operates at sub-atmospheric pressure to favor CPD formation, then conversion is improved, but air and oxygen ingress causes equipment damage
Solution Approach 1:
The patent introduces an intermediary inert gas (nitrogen or carbon dioxide) that serves as a buffer between the atmospheric environment and the reaction zone. This intermediary gas allows the reactor to operate at sub-atmospheric pressure favorable for CPD formation while preventing direct contact between air/oxygen and the sensitive catalyst and CPD product, thus avoiding equipment damage and unwanted oxidation reactions.
3Manufacturing precision
If conventional distillation is used to separate CPD from C5 hydrocarbons, then separation is attempted, but CPD loss occurs due to azeotropes and reactivity
Solution Approach 1:
The patent changes the separation parameter from conventional distillation (which relies on boiling point differences) to extraction or adsorption methods. By using an selective solvent or adsorbent material, CPD is separated based on its specific chemical interactions rather than volatility, avoiding the problems of azeotrope formation and thermal degradation that occur in distillation.
Solution Approach 2:
The patent replaces the mechanical separation system (distillation columns relying on vapor-liquid equilibrium) with a chemical separation system using selective solvents or adsorbents. This substitution eliminates the need for high-temperature vaporization that causes CPD loss through azeotropes and unwanted reactions, achieving high-purity separation at lower temperatures.
4Manufacturing precision
If dimerization process is used to recover CPD, then CPD can be separated from C5 hydrocarbons, but co-dimers form contaminating DCPD
Solution Approach 1:
The patent extracts CPD from the reaction mixture using a selective solvent or adsorbent that specifically binds CPD while leaving C5 hydrocarbons and other components in the raffinate. This extraction method isolates CPD before it can undergo dimerization reactions, obtaining pure CPD without co-dimer contamination and avoiding the need for subsequent cracking steps.
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 enables high-yield production of CPD with high-purity DCPD, reducing downstream processing costs and preventing equipment damage by maintaining acceptable pressure conditions and minimizing unwanted reactions.
Implementation Method 1
contacting the at least one acyclic C5 hydrocarbon with a catalyst under conversion conditions to obtain a first reactor hydrocarbon effluent
Implementation Method 2
sufficient light hydrocarbon co-feedstock is provided in step (I) such that: (i) the total absolute pressure of the first reactor hydrocarbon effluent at the outlet is P(fre); (iv) P(fre) is greater than 100 kilopascal absolute
Implementation Method 3
an effective separation process to minimize Diels-Alder reactions, allowing for high-yield production of CPD and high-purity DCPD
Implementation Method 4
DCPD can be thermally depolymerized (aka cracked) via retro-Diels-Alder reaction to CPD at the point of use
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Processes and systems for making cyclopentadiene and/or dicyclopentadiene include converting acyclic C5 hydrocarbon(s) into CPD in a first reactor in the presence of a C1-C4 co-feedstock to obtain a product mixture, separating the product mixture in a separation sub-system such as compression train to obtain a C5-rich fraction comprising CPD and essentially depleted of hydrogen and C1-C4 hydrocarbons, dimerizing the C5-rich fraction in a dimerization reactor to obtain a product effluent comprising DCPD, followed by separating the product effluent to obtain a DCPD-rich fraction. Multiple-stage of dimerization and separation steps can be optionally used to obtain multiple DCPD-rich fractions of various degrees of purity and quantity. C5-rich fractions from various stages of the process may be recycled to the first reactor, or converted into mogas components after selective hydrogenation. C5-rich fractions and mogas components may be optionally separated to produce value-adding chemicals.