Catalytic Cracking Coking Prevention via Spent Catalyst Adsorption
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Solution Overview
Problem
Coking phenomena in catalytic cracking systems for producing light olefins from crude oil lead to device malfunction and reduced operation periods, particularly in disengagers and heat exchange devices, due to inadequate heat management and catalyst utilization.
Innovation Solution
Cooling high temperature oil gas and adsorbing condensed liquids on spent catalysts before entering the disengager, with the catalyst being directly delivered to the disengager for gas-solid separation, and using the catalyst to absorb and remove coke precursors from heat exchanger walls, thereby preventing coking and optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high temperature oil gas is directly delivered to the disengager for gas-solid separation, then the operation speed is maintained, but coking occurs in the disengager and heat exchange device
Solution Approach 1:
The patent applies preliminary action by cooling the high temperature oil gas before it enters the disengager. A cooling device is installed between the reactor and disengager to reduce the temperature of oil gas in advance, preventing coking from occurring in the disengager and heat exchange devices while maintaining continuous operation.
Solution Approach 2:
The patent uses an intermediary substance (cooling medium) to transfer heat from the high temperature oil gas. The cooling device introduces a cooling medium that absorbs excess heat from the oil gas, acting as an intermediary to prevent direct thermal decomposition and coking in subsequent equipment.
2Use of energy by moving object
If heat exchange of high temperature oil gas is used in generating high pressure steam for cooling, then energy utilization is improved, but the heat exchange tube will surely coke
Solution Approach 1:
The patent applies preliminary action by cooling the oil gas before it reaches the heat exchange device. By reducing the temperature of oil gas in advance through the cooling device, the oil gas is less prone to decompose and form coke on the heat exchange tube surfaces, enabling sustained energy utilization without coking problems.
3Object-affected harmful factors
If the temperature of high temperature oil gas is cooled before entering the disengager, then coking is reduced, but energy loss increases
Solution Approach 1:
The patent converts the harmful excess heat that would cause coking into a useful resource by using it to generate high pressure steam in the heat exchange device. The cooling process is not merely waste removal but energy recovery, where the thermal energy is utilized for steam generation before the cooled oil gas enters the disengager.
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
Significantly reduces coking in disengagers and heat exchangers, prolongs device operation periods, and enhances energy efficiency by utilizing catalysts to absorb condensed oils and prevent wall coking, while generating high-pressure steam for energy utilization.
Implementation Method 1
cooling the temperature of high temperature oil gas discharged from a reactor, and adsorbing a liquid-phase oil condensed on a spent catalyst
Implementation Method 2
generating high-pressure steam for energy utilization
Data Source
AI summary
A method for preventing coking in a reaction system for producing light olefins from crude oil by catalytic cracking includes: reducing temperature of oil gas discharged from a reactor, adsorbing a condensed liquid-phase oil by a spent catalyst, allowing a cooled oil gas to enter a disengager for gas-solid separation, and delivering most of the spent catalyst to the disengager. The above method is taken to avoid coking of the reaction system and to ensure stable operation of a device for a long period of time; and the high-temperature potential heat of the oil gas is fully utilized, making the energy utilization of the whole system more reasonable, and achieving the effects of energy saving and emission reduction.