Hydrocracking Prefractionator for Naphtha Splitter Elimination
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Solution Overview
Problem
Current hydrocracking recovery processes are inefficient in producing petrochemical feedstock from hydrocracked distillate stocks, relying heavily on external utilities for heating and requiring multiple columns for fractionation, which increases energy consumption and capital expenses.
Innovation Solution
A process that integrates a cold stripping column and a hot stripping column with a prefractionator, feeding their streams into a product fractionation column, which produces three products (light naphtha, heavy naphtha, and unconverted oil) without the need for separate naphtha splitter columns, optimizing energy use and reducing column requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple fractionation columns are used to separate hydrocracked products, then product separation precision is improved, but device complexity and capital expenses increase
Solution Approach 1:
The patent combines the functions of multiple fractionation columns into a single integrated product fractionation column. This column is designed to simultaneously separate light naphtha, heavy naphtha, and unconverted oil in one unit, eliminating the need for separate naphtha splitter columns while maintaining product separation precision through optimized internal tray configurations and fractionation zones.
Solution Approach 2:
The product fractionation column is designed as a multi-functional unit that performs multiple separation tasks simultaneously. It fractionates different product streams (light naphtha, heavy naphtha, unconverted oil) within a single column structure, making the equipment versatile and reducing the overall number of units required in the hydrocracking recovery section.
2Reliability
If external utilities are used to provide heater duty for vaporization, then process reliability is improved, but energy efficiency deteriorates
Solution Approach 1:
The hydrocracking unit is designed to generate its own heat requirements through internal heat integration. The hydrocracking reactor and fractionation processes are thermally coupled, allowing heat generated within the unit to be reused for vaporization and heating duties. This self-service approach reduces dependence on external utilities while maintaining process reliability through controlled thermal management.
Solution Approach 2:
The patent implements continuous heat recovery and utilization throughout the process. Heat from hot streams is continuously transferred to cooler streams needing heating, creating a continuous cycle of useful thermal action. This minimizes energy losses and reduces the need for external heater duty while ensuring continuous reliable operation.
3Manufacturing precision
If steam stripping is used to separate volatile materials, then separation effectiveness is improved, but steam consumption and operational costs increase
Solution Approach 1:
The patent modifies the stripping process by changing operational parameters such as temperature, pressure, and gas flow rates to optimize separation effectiveness. By adjusting these parameters, the process achieves efficient separation of volatile materials from heavier hydrocarbons while minimizing steam consumption and reducing operational costs.
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 reduces steam usage, lowers heater duty, and eliminates the need for additional columns, resulting in capital and operational savings while improving the efficiency of hydrocracked product recovery.
Implementation Method 1
Stripping columns typically rely on steam stripping to separate volatile materials from heavier hydrocarbon materials.
Implementation Method 2
A liquid stripping stream is fractionated in a deethanizer column... The product fractionation column separates the stripped liquid hydrocracked stream into an overhead fractionated stream comprising naphtha...
Data Source
AI summary
A process and apparatus for hydrocracking a hydrocarbon stream that feeds a cold stripped stream and a hot stripped stream to a prefractionator from which a prefractionated overhead stream and a prefractionated bottoms stream are passed to a product fractionation column. The product fractionation column may produce three products, light naphtha, heavy naphtha and distillate omitting the need for a naphtha splitter column.