Dual-Stripper Hydroprocessing Recovery System
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Solution Overview
Problem
Hydroprocessing recovery units are energy-intensive due to the need for severe process conditions and high heater duty to heat stripped effluents before fractionation, which is inefficient and costly, especially when dealing with desulfurized residue and lighter hydrocarbons.
Innovation Solution
Implementing a dual-stripper system where a hot stripper processes hot hydroprocessed effluents and a cold stripper processes cold effluents separately, allowing for efficient removal of hydrogen sulfide and lighter hydrocarbons without heating the desulfurized residue, thereby reducing energy consumption and capital costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single stripper is used to process all hydroprocessed effluents, then the equipment complexity is reduced, but the energy consumption increases due to the need to heat all effluents to fractionation temperature
Solution Approach 1:
The invention divides the single stripper into two separate strippers: a hot stripper for hot effluents and a cold stripper for cold effluents. This segmentation allows each stripper to be optimized for its specific temperature range, with the cold stripper producing a cold stripped effluent that bypasses the fired heater, thereby reducing energy consumption while maintaining manageable equipment complexity through functional specialization.
2Productivity
If all hydroprocessed effluents are heated to fractionation temperature, then complete product recovery is achieved, but the heater duty and capital costs increase
Solution Approach 1:
The invention applies different temperature handling strategies to different effluent streams based on their initial temperatures. Cold effluents are processed in the cold stripper and sent directly to fractionation without heating, while hot effluents are processed in the hot stripper and heated as needed. This local quality approach ensures product recovery for all streams while minimizing heater duty by avoiding unnecessary heating of cold streams.
3Manufacturing precision
If severe process conditions are used for hydroprocessing, then contaminant removal efficiency is improved, but the energy intensity increases
Solution Approach 1:
The invention performs preliminary separation of effluents into hot and cold streams before further processing. By separating the effluents early in the process and routing cold effluents through the cold stripper to bypass the fired heater, the system maintains the contaminant removal efficiency achieved by severe hydroprocessing conditions while reducing the subsequent energy intensity required for heating and fractionation.
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 significantly reduces energy costs and capital expenditures by minimizing the need for a fired heater, while maintaining efficient processing and product recovery, including the production of ultra-low sulfur diesel and other valuable hydrocarbons.
Implementation Method 1
a hot stripper in communication with the hydroprocessing reactor for stripping a relatively hot hydroprocessing effluent stream
Implementation Method 2
a cold stripper in communication with the hydroprocessing reactor for stripping a relatively cold hydroprocessing effluent stream
Implementation Method 3
a stripper for stripping hydroprocessed effluent with a stripping medium such as steam to remove unwanted hydrogen sulfide
Data Source
AI summary
An apparatus is disclosed for recovering hydroprocessing effluent from a hydroprocessing unit utilizing a hot stripper and a cold stripper. A net overhead stream from the hot stripper is forwarded to the cold stripper for further stripping. The invention is particularly suitable for hydrotreating residue feed streams. The hot stripped stream may be subjected to fluid catalytic cracking. The apparatus and process eliminates the need for a fired heater in the product recovery unit.