Integrated Hydrocracking and FCC System for Flexible Yield Control
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Solution Overview
Problem
Current hydrocracking and fluidized catalytic cracking processes lack flexibility and efficiency in producing high-value products like light olefins and middle distillates, with individual processes often resulting in suboptimal yields and product quality.
Innovation Solution
An integrated process combining hydrocracking and fluidized catalytic cracking, where hydrocarbon feedstocks are first hydrotreated and cracked, then fractionated, with the high-boiling fraction further cracked in a fluidized catalytic cracking zone to produce olefins and gasoline, and the cycle oil further hydrogenated and cracked, allowing for flexible product yield adjustment based on hydrocracker conversion levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrocracking processes are used to process feedstocks and improve product quality, then hydrogen to carbon ratio increases and organosulfur/organonitrogen compounds are removed, but the process lacks flexibility in adjusting product yields between light olefins and middle distillates
Solution Approach 1:
The patent combines hydrocracking and fluidized catalytic cracking (FCC) processes into a single integrated system where the hydrocracker and FCC unit are connected through a common feedstock supply and product distribution network, allowing the system to function as both a hydrocracker and an FCC unit independently or in combination
Solution Approach 2:
The system employs dynamic control mechanisms that allow operators to adjust the conversion level of the hydrocracker and the feed distribution between the hydrocracker and FCC unit in real-time, enabling flexible adjustment of product yields between light olefins and middle distillates based on market demands
2Quantity of substance
If FCC operations use short contact time between feedstock and catalyst to produce light olefins, then light olefin yield increases, but feed conversion becomes relatively low
Solution Approach 1:
The integrated system performs preliminary hydrocracking treatment on the feedstock before it enters the FCC unit, pre-processing the feed to optimize its composition for subsequent FCC reactions, which enhances both light olefin yield and overall feed conversion when operating in combination mode
3Quantity of substance
If pentasil-type zeolite catalyst is used in FCC operations to enhance light fraction hydrocarbon yield, then light fraction yield increases, but excessive cracking of gasoline fraction occurs which is also a high value product
Solution Approach 1:
The system uses different catalyst types in different units - the hydrocracker employs catalysts optimized for hydrocracking reactions while the FCC unit uses catalysts tailored for catalytic cracking, with each catalyst performing its specialized function to minimize unwanted side reactions and preserve high-value products
4Quantity of substance
If high temperature cracking is used in FCC operations to produce light olefins, then light olefin production increases, but relatively high levels of dry gases production occur
Solution Approach 1:
The system employs precise control of operating parameters including temperature, pressure, and contact time in both the hydrocracker and FCC unit, allowing optimization of light olefin production while minimizing excessive cracking that leads to dry gas formation through coordinated parameter adjustment across both units
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 integrated process enhances flexibility and yield, achieving middle distillate production of 10-60% and light olefin production of 3-20% while minimizing side products, with yields inversely proportional to hydrocracker conversion levels, allowing for optimized product slates.
Implementation Method 1
hydrocracking processes split the molecules of the feed into smaller, i.e., lighter, molecules having higher average volatility and economic value. Additionally, hydrocracking processes typically improve the quality of the hydrocarbon feedstock by increasing the hydrogen to carbon ratio and by removing organosulfur and organonitrogen compounds
Implementation Method 2
petroleum derived hydrocarbons are catalytically cracked with an acidic catalyst maintained in a fluidized state
Implementation Method 3
passing the first zone effluent to a fractionating zone to produce at least a low boiling fraction and a high boiling fraction
Implementation Method 4
introducing the feedstock and hydrogen into a first hydrocracking reaction zone containing a first hydrocracking catalyst to produce a first zone effluent
Data Source
AI summary
A system and method of cracking hydrocarbon feedstocks is provided that allows for significant flexibility in terms of the desired product yield. An integrated process includes introducing the feedstock and hydrogen into a first hydrocracking reaction zone containing a first hydrocracking catalyst to produce a first zone effluent. The first zone effluent is passed to a fractionating zone to produce at least a low boiling fraction and a high boiling fraction, and optionally one or more intermediate fractions. The bottoms fraction is conveyed to a fluidized catalytic cracking reaction and separation zone, from which olefins and gasoline are recovered. At least a portion of remaining cycle oil is passed from the fluidized catalytic cracking reaction and separation zone to a second hydrocracking reaction zone containing a second hydrocracking catalyst to produce a second stage effluent. At least a portion of the second stage effluent is recycled to the fractionating zone and/or the first hydrocracking reaction zone.