Light Aromatic Hydrocarbon Conversion with LCO Post-Saturation Recycling
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Solution Overview
Problem
Existing LCO conversion technologies struggle to efficiently produce light aromatic hydrocarbons, leading to low yields and high aromatic hydrocarbon loss, with hydrofining processes being insufficient for cetane number requirements and hydrocracking processes failing to maximize aromatic hydrocarbon production.
Innovation Solution
A two-stage process involving hydrofining and selective conversion, followed by sequential separation and low-temperature, low-pressure hydrogenation saturation, to produce light aromatic hydrocarbons with high yields and reduced hydrogen consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hydrofining process is used to improve cetane number, then colour and stability are improved, but aromatic hydrocarbon retention rate decreases and hydrogen consumption increases
Solution Approach 1:
The hydrofining process is divided into two stages: first stage uses a hydrofining catalyst to remove impurities and improve colour/stability, while the second stage uses a selective conversion catalyst to convert polycyclic aromatic hydrocarbons to monocyclic aromatic hydrocarbons, thereby preserving aromatic hydrocarbon content while achieving the desired product quality
Solution Approach 2:
The process changes operating parameters between stages: first stage uses higher temperature (300-420°C) and pressure (3-10 MPa) for hydrofining, while second stage uses lower temperature (260-380°C) and pressure (2-8 MPa) for selective conversion, optimizing both aromatic retention and product quality
2Productivity
If hydrocracking process is used to produce light aromatic hydrocarbons, then conversion efficiency is improved, but aromatic hydrocarbon loss increases and yield is reduced
Solution Approach 1:
The catalyst system is designed with different local functions: the hydrofining catalyst provides hydrofining activity for impurity removal, while the selective conversion catalyst provides hydrocracking activity with high selectivity for producing light aromatic hydrocarbons, minimizing aromatic loss through optimized catalyst composition and structure
Solution Approach 2:
The process uses composite catalyst systems combining hydrofining catalyst (with metal sulfides on alumina support) and selective conversion catalyst (with zeolite and metal components), where each catalyst material contributes specific properties to achieve both high conversion efficiency and high aromatic hydrocarbon retention
3Speed
If high temperature and high pressure are used in hydrofining, then reaction rate is improved, but aromatic hydrocarbon saturation increases and retention rate decreases
Solution Approach 1:
The hydrofining process is performed as a preliminary action in the first stage to remove impurities and improve product quality, while the selective conversion process follows in the second stage to preserve and convert aromatic hydrocarbons, separating the functions to avoid excessive saturation
Solution Approach 2:
The process dynamically adjusts operating conditions between stages: first stage uses higher temperature and pressure for rapid hydrofining, while second stage uses milder conditions for selective conversion, optimizing reaction rate while controlling aromatic saturation through dynamic parameter adjustment
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 achieves high yields of light aromatic hydrocarbons, exceeding 98% aromatic hydrocarbon retention and reducing hydrogen consumption, addressing the inefficiencies of existing methods.
Implementation Method 1
hydrogenation saturation of olefin, desulfurization, denitrification and partial saturation of aromatic hydrocarbon under the condition of medium or low pressure
Implementation Method 2
LCO is converted into light aromatic hydrocarbon through hydrocracking reaction
Implementation Method 3
subjected to high-selectivity hydrogenation saturation under the conditions of low temperature and low pressure to provide a product having one benzene ring
Data Source
AI summary
Provided are a full conversion process and a device thereof for producing light aromatic hydrocarbon from LCO. The process includes the steps of: subjecting LCO stream to hydrofining and impurity separation, then performing selective conversion reaction, and separating the mixed aromatic hydrocarbons generated to sequentially separate out light aromatic hydrocarbons such as benzene-toluene and xylene, C9A aromatic hydrocarbons, C10A aromatic hydrocarbons and a bottom heavy tail oil; feeding the bottom heavy tail oil into a post-saturation selective reactor, subjecting to high-selectivity hydrogenation saturation under the conditions of low temperature and low pressure to provide a product having one benzene ring, and then returning the product back to the selective conversion reactor. The full-cut conversion of producing light aromatic hydrocarbon from LCO is achieved, resulting in the technical effects of high yields of monocyclic aromatic hydrocarbons such as benzene-toluene, xylene, C9A aromatic hydrocarbons, C10A aromatic hydrocarbons and the like.