Reactive Feedstock Stabilization via Diluent Mediator
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Solution Overview
Problem
Reactive liquid feedstocks from renewable sources, such as pyrolysis and hydrothermal liquefaction, are challenging to process due to their high reactivity, leading to polymerization and heat release issues, which increase equipment size and energy requirements when recycling is employed.
Innovation Solution
A process involving a high recycle ratio in an initial reactor, using a diluent stream to stabilize the reactive feedstock, reducing hydrogen consumption and preventing polymerization, while maintaining a uniform chemical nature and higher heat capacity, is introduced. This process includes directing a combined stream of the reactive feedstock and diluent to contact catalytically active materials at controlled temperatures for hydrotreatment, followed by further processing to produce stabilized hydrocarbon products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If recycle is employed to handle heat release from reactive liquid feedstock conversion, then heat management is improved, but equipment size and energy requirements increase
Solution Approach 1:
An inert diluent stream is introduced as an intermediary substance to absorb excess heat from the exothermic conversion of reactive liquid feedstock. The diluent acts as a thermal buffer, preventing temperature runaway without requiring equipment expansion for recycle streams. This mediator approach allows heat management while maintaining compact equipment dimensions.
Solution Approach 2:
The process changes the thermal parameters of the reaction system by introducing a diluent that modifies the heat capacity and temperature profile of the conversion process. By adjusting the diluent-to-feedstock ratio, the exothermic heat release is controlled and distributed over a larger thermal mass, enabling effective heat management without increasing equipment volume.
2Temperature
If recycle is employed to handle heat release from reactive liquid feedstock conversion, then heat management is improved, but energy requirements increase
Solution Approach 1:
The inert diluent serves as a thermal mediator that absorbs and distributes reaction heat without requiring energy-intensive recycle pumping. The diluent's high heat capacity allows it to carry thermal energy through the system passively, reducing the need for active thermal management and associated energy consumption.
Solution Approach 2:
The exothermic heat release, which is potentially harmful if uncontrolled, is converted into a beneficial thermal resource by using the diluent to absorb and redistribute this heat. The reaction heat warms the diluent, which then serves as a preheating medium for incoming feedstock, converting waste heat into useful thermal energy and reducing overall energy requirements.
3Productivity
If reactive liquid feedstock is processed without dilution, then conversion efficiency is maintained, but polymerization and solidification occur
Solution Approach 1:
The concentration parameters of the reactive feedstock are modified by introducing an inert diluent. This changes the reaction kinetics and thermodynamics, reducing the probability of polymerization reactions while maintaining the primary conversion efficiency. The diluent effectively lowers the partial pressure and concentration of reactive species, suppressing unwanted side reactions.
Solution Approach 2:
The diluent creates local dilution zones within the reaction system where reactive species are isolated from each other, reducing intermolecular interactions that lead to polymerization. This local quality change maintains conversion efficiency for the desired reaction while preventing solidification and polymerization in specific regions of the reactor.
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
The process effectively stabilizes the reactive feedstock, reducing equipment size and energy needs, while ensuring efficient conversion and product stability, thereby addressing the challenges of reactivity and heat management in processing renewable feedstocks.
Implementation Method 1
contact a material catalytically active in hydrotreatment which during operation has a lowest temperature of at least 80° C. and a highest temperature of less than 250° C. in the presence of dihydrogen
Implementation Method 2
contact a material catalytically active in hydrotreatment
Implementation Method 3
the combined stream having a first hydrogen consumption potential... contact a material catalytically active in hydrotreatment which during operation has a lowest temperature of at least 80° C. and a highest temperature of less than 250° C.
Data Source
AI summary
A process and a process plant for conversion of a reactive liquid feedstock stream containing at least 40 wt % carbon, including the steps of directing a diluent stream, having a first combined hydrogen consumption potential and the reactive liquid feedstock stream as a combined stream having a first hydrogen consumption potential, to contact a material catalytically active in hydrotreatment which during operation has a lowest temperature of at least 80° C. and a highest temperature of less than 250° C. in the presence of dihydrogen, withdrawing a stabilized composition stream having a second combined hydrogen consumption potential which is less than 80% and more than 10% of the first hydrogen consumption potential, and providing an amount of the liquid phase of said stabilized composition stream as said diluent stream wherein the hydrogen consumption potential for a composition is the amount of hydrogen required for conversion of the composition into a saturated hydrocarbon.