Naphtha Methanol Cracking in Circulating Fluidized-Bed Reactor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for producing light olefins through naphtha and methanol cracking reactions face challenges in achieving high yields due to differences in reaction speed and heat generation, leading to excessive energy consumption and by-product formation.
Innovation Solution
A naphtha and methanol mixed catalytic cracking process using a circulating fluidized-bed reactor, where naphtha is introduced at the bottom and methanol at a position between 15% to 45% of the reactor length, allowing for precise control of contact time and heat neutralization, thereby minimizing energy consumption and by-product production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If methanol and naphtha are cracked simultaneously in a simple coupling reaction, then heat neutralization is achieved, but light olefin yield increases are limited due to excessive by-product formation from methanol's faster reaction rate
Solution Approach 1:
The patent divides the cracking process into two separate reactors: a first cracking reactor for naphtha and a second cracking reactor for methanol. This segmentation allows independent optimization of reaction conditions for each feedstock, preventing the by-product formation issues that arise from simple coupling while maintaining heat neutralization benefits
Solution Approach 2:
Naphtha is cracked first in the first cracking reactor to generate heat and produce intermediate hydrocarbons. The heat generated is then utilized in the second cracking reactor for methanol conversion. This preliminary action ensures optimal temperature control and prevents excessive by-product formation
2Productivity
If methanol cracking is performed alone, then light olefins are produced through exothermic reaction, but excessive heat generation occurs that must be eliminated
Solution Approach 1:
The patent combines methanol cracking with naphtha cracking in a two-reactor system where the exothermic methanol reaction is merged with the endothermic naphtha cracking process. The heat generated from methanol cracking is transferred to drive naphtha cracking, achieving thermal coupling that eliminates excessive heat generation while maintaining high light olefin production
3Productivity
If naphtha cracking is performed alone through endothermic pyrolysis, then light olefins are produced, but huge energy consumption occurs
Solution Approach 1:
The system uses the heat generated from methanol cracking to self-supply the energy required for naphtha cracking. The exothermic reaction of methanol provides the endothermic heat demand of naphtha cracking, making the overall process energy-self-sufficient and eliminating the need for external energy input
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 approach enhances the yield of light olefins while reducing the production of saturated hydrocarbons like methane, ethane, and propane, improving energy efficiency and economic viability.
Implementation Method 1
a naphtha and methanol mixed catalytic cracking reaction process involving a simultaneous cracking reaction of naphtha and methanol by using a circulating fluidized-bed reactor
Implementation Method 2
hydrocarbon cracking process is endothermic reaction and methanol cracking process is exothermic reaction. So, a coupling reaction of the two processes above is proposed for heat neutralization
Implementation Method 3
simultaneous cracking reaction of naphtha and methanol by using a circulating fluidized-bed reactor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides a naphtha and methanol mixed catalytic cracking reaction process involving a simultaneous cracking reaction of naphtha and methanol using a circulating fluidized-bed reactor comprising a reactor, a stripper, and a regenerator, wherein the naphtha is supplied from the bottom part of the reactor at a position between 0% ∼ 5% of the total length of the reactor, and the methanol is supplied from the bottom part of the reactor at a position between 10% ∼ 80% of the total length of the reactor. The catalytic cracking reaction process provided by the invention uses the circulating fluidized-bed reactor and can crack naphtha and methanol simultaneously by having different introduction positions for the naphtha and methanol in the reactor, which is advantageous for heat neutralization, so that energy consumption can be minimized and also the yield of light olefins can be improved by suppressing the production of light saturated hydrocarbons such as methane, ethane and propane.