Liquid-Phase Reactor with Inorganic Membrane for Heavy Oil Hydrogenation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heavy oil hydrogenation reactors face challenges such as low reaction rates, insufficient conversion, and side reactions due to high viscosity and uneven temperature distribution, which affect the efficiency and yield of the hydrogenation process.
Innovation Solution
A liquid-phase reactor with a double cylinder structure, featuring a shell-and-tube design with an inorganic membrane tube, reduces viscosity through gas diffusion and shearing action, improving mass transfer and reaction rates, and allows for controlled catalyst contact times to mitigate coking and deep cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If up-flow liquid-phase hydrogenation process is adopted, then hydrogenation rate and reaction efficiency are improved, but mass transfer rate is low due to high viscosity of heavy oil
Solution Approach 1:
The reactor is divided into two distinct zones: an upper reaction zone and a lower mixing zone. The upper zone contains catalyst for hydrogenation reaction, while the lower zone contains a mixer to enhance mass transfer. This segmentation allows simultaneous optimization of reaction efficiency and mass transfer rate.
Solution Approach 2:
A mixer is introduced as an intermediary device in the lower zone to facilitate mass transfer between hydrogen and heavy oil. The mixer acts as a mediator that overcomes the low mass transfer rate caused by high viscosity, enabling efficient hydrogenation in the upper zone.
2Productivity
If residence time is extended to achieve desired reaction degree, then conversion rate is improved, but side reaction and cracking increase causing coking of catalyst
Solution Approach 1:
The reactor is segmented into an upper reaction zone and a lower mixing zone. The upper zone provides controlled residence time for desired hydrogenation reaction, while the lower zone with mixer prevents excessive residence time by enhancing mixing and reducing local concentration gradients, thus preventing coking.
Solution Approach 2:
The mixer in the lower zone creates a feedback mechanism that continuously mixes reactants and products, preventing excessive residence time in any single location. This feedback control ensures optimal conversion while preventing side reactions and catalyst coking.
3Device complexity
If conventional fixed bed reactor is used, then structure is simple, but temperature distribution is uneven causing low reaction efficiency
Solution Approach 1:
The reactor is segmented into functional zones: an upper reaction zone with catalyst and a lower mixing zone with mixer. This segmentation enables better temperature control and distribution while maintaining relatively simple overall structure.
Solution Approach 2:
The mixer in the lower zone introduces mechanical mixing action that enhances temperature and concentration distribution. This mechanical action prevents temperature gradients and ensures uniform reaction conditions throughout 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 reactor enhances the mass transfer driving force and reaction rate, improves liquid yield, and reduces impurity content, achieving better conversion rates and product distribution compared to conventional systems.
Implementation Method 1
pores are provided in the tube wall of the inorganic membrane tube as a gas passage... the gas material can diffuse into the liquid material through the pores provided in the tube wall of the inorganic membrane tube
Implementation Method 2
apply a shearing action on the liquid material, so as to uniformly disperse/dissolve into the liquid material to reduce its viscosity
Implementation Method 3
the upper cylinder is filled with a first catalyst, and the annular space is filled with a second catalyst... subjecting it to a first hydrogenation reaction... subjecting the partially hydrogenated reaction material to a second hydrogenation reaction
Implementation Method 4
improve the dissolution and dispersion amount and dispersion uniformity of the gas material in the liquid material... improve the mass transfer driving force and the reaction rate
Data Source
AI summary
A liquid-phase reactor has an outer cylinder and an inner cylinder disposed along an axial direction of the reactor. The outer cylinder has a top head, a straight cylinder section and a bottom head. An annular space is formed between the inner cylinder and the outer cylinder. A top end of the inner cylinder is open and is in communication with the annular space. The inner cylinder has an upper cylinder and a lower cylinder sequentially from top to bottom. The upper cylinder is positioned in the straight cylinder section, with its cross-sectional area being gradually reduced from top to bottom. The lower cylinder is positioned in the bottom head, with its cross-sectional area being gradually increased from top to bottom. An inorganic membrane tube extending along the axial direction of the reactor is provided in the lower cylinder so that a shell-and-tube structure is formed.