Gaseous Phase Cracking Process for Maximizing Olefin Yield
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Solution Overview
Problem
Current petroleum processing technologies face challenges in maximizing the production of low-carbon olefins and aromatic hydrocarbons from heavy crude oil due to limitations in catalyst efficiency, energy consumption, and the 'cage effect' in liquid phase reactions, leading to reduced yield and selectivity, as well as increased coke generation.
Innovation Solution
A process involving millisecond pyrolysis of crude oil in a downflow pipe followed by high-temperature gaseous phase catalytic cracking, combined with hydrogenation of diesel fractions and oil slurry, to enhance the yield and selectivity of olefins and aromatic hydrocarbons, while reducing energy consumption and coke formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional liquid phase catalytic cracking is used to process heavy crude oil, then the process can handle heavy feedstock, but the 'cage effect' limits free radical diffusion and increases condensation polymerization, reducing olefin yield and selectivity
Solution Approach 1:
The patent transitions from liquid phase to gaseous phase catalytic cracking. By vaporizing the crude oil feedstock before introducing it to the catalyst, the reaction occurs in the gas phase where free radicals can diffuse freely without the cage effect. This phase transition eliminates the harmful liquid phase constraints and significantly improves olefin yield and selectivity.
Solution Approach 2:
The patent changes the physical state parameter of the reactants from liquid to gas. By heating the crude oil to its vaporization temperature and maintaining gaseous conditions throughout the cracking process, the system achieves superior mass transfer and reaction kinetics compared to liquid phase operation.
2Adaptability or versatility
If traditional catalytic cracking processes are used with heavy oil, then feedstock flexibility is improved, but catalyst pore channels become blocked by coking and condensation, reducing conversion rate and selectivity
Solution Approach 1:
The gaseous phase reaction prevents heavy oil macromolecules from condensing and blocking catalyst pores. By maintaining the reaction in the gas phase, the system avoids the formation of condensed deposits that would otherwise accumulate on the catalyst surface and within pore channels, thereby preserving catalyst activity and reliability.
Solution Approach 2:
The patent converts the potential harm of heavy oil components into benefit by using gaseous phase cracking. The high temperature vaporization that would normally cause coking instead promotes complete vaporization and prevents condensation, turning the problematic heavy components into reactive gas-phase molecules that can be efficiently cracked.
3Productivity
If high temperature and long residence time are used in catalytic cracking, then conversion of heavy oil is improved, but energy consumption increases and coke generation is excessive
Solution Approach 1:
The patent uses short residence time gaseous phase cracking to achieve high conversion rates. By optimizing the reaction conditions in the gas phase with proper catalyst selection and temperature control, the process achieves efficient cracking in a brief period, avoiding the need for prolonged high-temperature exposure that would waste energy and generate excessive coke.
Solution Approach 2:
The patent changes the optimization parameters from long residence time to short residence time with enhanced temperature and catalyst efficiency. By adjusting these parameters in the gas phase, the system achieves superior conversion efficiency with reduced energy input and minimized coke formation.
4Manufacturing precision
If shape selective catalysts with small pore structures are used for heavy oil cracking, then product selectivity is improved, but diffusion of large heavy oil molecules is limited, reducing cracking efficiency
Solution Approach 1:
The gaseous phase environment enables large heavy oil molecules to diffuse freely to the catalyst surface without being constrained by liquid phase viscosity or pore size limitations. The gas phase provides excellent mass transfer characteristics that overcome the diffusion barriers present in liquid phase systems.
Solution Approach 2:
The patent uses a two-stage catalytic system with different catalyst functions. The first stage uses a catalyst optimized for breaking down large heavy molecules into smaller fragments, while the second stage uses a shape selective catalyst to convert these smaller molecules into desired olefin products with high selectivity. This segmentation allows each catalyst to operate in its optimal performance range.
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 process significantly increases the yield of low-carbon olefins and aromatic hydrocarbons, improves catalyst efficiency, and minimizes energy consumption and coke generation, effectively overcoming the 'cage effect' and optimizing the utilization of crude oil resources.
Implementation Method 1
a high temperature oil and gas is used for preparing low carbon olefins by directly subjecting to high temperature millisecond shape selective catalytic cracking
Implementation Method 2
high temperature millisecond shape selective catalytic cracking
Implementation Method 3
hydrogenation of diesel fractions and oil slurry, to enhance the yield and selectivity of olefins and aromatic hydrocarbons
Data Source
AI summary
The invention provides a process of maximizing production of chemical raw materials by gaseous phase catalytic cracking crude oil with multi-stages in milliseconds in combination with hydrogenation, comprising: a high-efficiency atomizing nozzle sprays the preheated crude oil into an upper portion of the downflow modification reaction tube, the produced oil mist is mixed with a high temperature heat carrier flowing downward from a first return controller for pyrolysis in milliseconds and then the pyrolysis products are subject to a gas-solid separation; the coked heat carrier obtained by the separation enters into a modification regeneration reactor to conduct a regeneration reaction, the obtained high temperature heat carrier returns to a top of the downflow reaction tube to participate in circulation, the regeneration gas is subject to heat exchange and then output; the high temperature oil and gas produced by the pyrolysis reaction directly flow into the millisecond cracking reactor and conduct a cracking reaction with the regenerated cracking catalyst and subject to a gas-solid separation; then the cracking catalyst to be regenerated enters the crack regeneration reactor and performs a regeneration reaction and then are subject to a gas-solid separation, the obtained high temperature crack catalyst passes through a second return controller and flows into the millisecond cracking reactor to participate the circulation reaction, the obtained flue gas is subject to heat exchange and then output; the cracked oil and gas produced by the cracking reaction enter into a fractionation tower for separation, thereby obtain the cracked gas, gasoline fraction, diesel fraction, recycle oil and oil slurry; furthermore, the diesel fraction, recycle oil and oil slurry are subject to saturation or open-ring in a hydrogenation reactor, return and mix with crude oil such that the mixture is used as a raw material.