Integrated Hydrocracking Vessel Liquid Seal
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Solution Overview
Problem
The existing hydrocracking processes are energy inefficient due to the need for separate hydrotreating and hydrocracking reaction zones, requiring duplicate pressuring and heating of the hydrocarbon feedstock, and the need to remove ammonia produced in the first stage to prevent catalyst deactivation in the second stage, which increases equipment costs and complexity.
Innovation Solution
An integrated process where the hydrotreated effluent from the hydrotreating zone is directly introduced into a hydrocracking vessel at the same pressure, using a liquid hydrocarbon seal to prevent hydrogen sulfide and ammonia from contacting the hydrocracking catalyst, and a hydrogen-rich gaseous stream is used for further conversion, minimizing equipment requirements and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate hydrotreating and hydrocracking reaction zones are used, then sulfur and nitrogen removal is achieved, but energy efficiency deteriorates due to duplicate pressuring and heating
Solution Approach 1:
The patent combines the hydrotreating and hydrocracking reaction zones into a single integrated reactor vessel, allowing both functions to occur in sequence within the same equipment. The feedstock passes through a hydrotreating catalyst bed first, then a hydrocracking catalyst bed, eliminating the need for separate vessels, pumps, and heat exchangers for each stage, thereby reducing energy consumption while maintaining effective sulfur and nitrogen removal.
2Reliability
If separate hydrotreating and hydrocracking reaction zones are used, then sulfur and nitrogen removal is achieved, but equipment complexity increases
Solution Approach 1:
The patent integrates multiple reaction zones into a single reactor vessel with multiple catalyst beds arranged in series. This consolidation reduces the number of separate equipment items including reactors, pumps, valves, and associated control systems, thereby simplifying the overall process equipment while maintaining the necessary chemical processing functions for sulfur and nitrogen removal.
3Object-affected harmful factors
If effluent is depressured and fractionated between stages, then ammonia separation is achieved, but process complexity and equipment requirements increase
Solution Approach 1:
The patent extracts and removes ammonia and other volatile impurities from the liquid effluent stream using a stripper column positioned between the hydrotreating and hydrocracking catalyst beds. The stripper uses steam or gas to strip volatile components from the liquid, and the cleaned liquid is then fed to the hydrocracking stage, eliminating the need for depressurization and fractionation equipment while effectively removing ammonia.
4Reliability
If liquid hydrocarbon seal is used, then ammonia and hydrogen sulfide are isolated from catalyst, but additional equipment is required
Solution Approach 1:
The patent introduces a liquid hydrocarbon seal as an intermediary barrier between the stripper section and the hydrocracking catalyst bed. This liquid seal traps ammonia and hydrogen sulfide in the stripper section while allowing the cleaned hydrocarbon stream to pass to the catalyst, protecting the catalyst from deactivation without requiring complex additional equipment beyond the integrated reactor design.
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 capital costs by minimizing equipment needs and improves operational efficiency by eliminating the need for duplicate pressuring and heating, while maintaining catalyst effectiveness by isolating hydrogen sulfide and ammonia from the hydrocracking catalyst.
Implementation Method 1
a liquid hydrocarbon seal prevents the flow of the vapor to the lower portion of the hydrocracking vessel which holds the hydrocracking catalyst
Implementation Method 2
The hydrocarbon feedstock is hydrotreated with hydrogen to remove sulfur and nitrogen to produce hydrogen sulfide and ammonia
Implementation Method 3
hydrocracking a hydrocarbon feedstock to produce useful lower boiling hydrocarbon products
Data Source
AI summary
A hydrocracking process wherein the feedstock is hydrotreated and the liquid and gaseous effluent from the hydrotreater is directly introduced into the upper end of a hydrocracking vessel which provides a liquid seal to prevent the passage of the gaseous stream containing hydrogen sulfide and ammonia from the hydrotreater to enter the hydrocracking zone containing hydrocracking catalyst. Fresh hydrogen is then introduced into the hydrocracking zone. An apparatus for hydrocracking a hydrocarbon feedstock is also disclosed.