Hydrocracking Light Fractionation Column with Three Products
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Solution Overview
Problem
Current hydrocracking recovery processes are inefficient in recovering petrochemical feedstock from hydrocracked distillate stocks, relying heavily on external utilities for heating and requiring multiple columns for fractionation, which increases energy consumption and operational costs.
Innovation Solution
The proposed process integrates a cold stripping column and a hot stripping column with a product fractionation column, including a prefractionator, to produce three products without the need for a separate deethanizer column, optimizing energy use and reducing capital and operational expenses by minimizing the need for external heating sources and additional fractionation columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a typical hydrocracking recovery section with multiple columns (deethanizer, debutanizer, naphtha splitter) is used, then complete fractionation into multiple products is achieved, but device complexity and operational costs increase
Solution Approach 1:
The patent combines the deethanizer column and debutanizer column into a single integrated fractionation column that produces three products (LPG, naphtha, and distillate) simultaneously. This merging eliminates the need for separate columns while maintaining complete fractionation capability, directly reducing device complexity without sacrificing product separation quality
Solution Approach 2:
The single fractionation column is designed to perform multiple functions: separating ethane from naphtha, separating naphtha from distillate, and producing three distinct product streams. This multi-functional design replaces what would traditionally require multiple specialized columns, achieving both simplified device complexity and maintained adaptability
2Ease of manufacture
If external utilities are used to provide heater duty for vaporization, then fractionation can be performed, but energy consumption increases
Solution Approach 1:
The fractionation column uses its own bottom products as heating sources through internal heat integration. The warmer bottom streams provide the necessary heater duty for vaporizing lighter components, eliminating the need for external utilities. This self-service approach maintains complete fractionation capability while significantly reducing energy consumption from external sources
Solution Approach 2:
Instead of discarding heat energy that would normally be lost in the fractionation process, the system recovers and utilizes it by directing warmer bottom products to provide heating duty for vaporization in the same column. This heat recovery approach transforms what would be waste heat into a useful resource, reducing overall energy consumption
3Reliability
If steam stripping is used to separate volatile materials, then hydrogen sulfide removal is achieved, but steam usage increases operational costs
Solution Approach 1:
The stripping column uses its own bottom products as heating sources to provide the necessary steam generation for hydrogen sulfide removal. The warmer bottom streams generate steam internally without requiring external steam utilities, maintaining reliable hydrogen sulfide removal while reducing steam usage and associated 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 enhances the efficiency of hydrocracking recovery by eliminating the need for external utilities for heating, reducing steam usage, and achieving capital savings by integrating processes within the hydrocracking unit, thereby improving the recovery of valuable hydrocarbon products like LPG and naphtha.
Implementation Method 1
Stripping columns typically rely on steam stripping to separate volatile materials from heavier hydrocarbon materials
Implementation Method 2
A liquid stripping overhead stream is fractionated in a deethanizer column whose overhead is sponged along with a vapor stripping overhead stream in an absorber column to product LPG
Implementation Method 3
A liquid stripping overhead stream is fractionated in a deethanizer column whose overhead is sponged along with a vapor stripping overhead stream in an absorber column to product LPG
Data Source
AI summary
A process and apparatus for hydrocracking a hydrocarbon stream that strips a liquid hydrocracked stream in a stripping column to provide a stripping overhead stream and a stripped stream. The stripping overhead stream fractionated to provide a light fractionated overhead stream, a light fractionated intermediate stream and a light fractionated bottoms stream in a single light fractionation column omitting the need for a separate deethanizer column.