Single Scrubbing Column for Cracking Gas Purification
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Solution Overview
Problem
The existing processes for purifying cracking gas from thermal cracking of liquid hydrocarbon-containing feeds are complex and require multiple scrubbing steps, including a complete oil scrubbing column, which increases apparatus outlay and operational complexity.
Innovation Solution
A simplified purification process using a single scrubbing column with a petroleum spirit-rich fraction and a water-rich fraction as successive scrubbing media, eliminating the need for a primary oil fractionator, where the cracking gas is directly introduced and purified in countercurrent flow through the column's sections, with the petroleum spirit-rich fraction removing heavy oil components and solid particles in the lower section and water-rich fraction removing petroleum spirit components in the upper section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complete oil scrubbing column is used for purifying cracking gas, then purification effectiveness is improved, but apparatus outlay and operational complexity increase
Solution Approach 1:
The patent merges the functions of heavy oil removal and petroleum spirit component removal into a single scrubbing column. The lower section removes heavy oil components and solid particles using a first scrubbing medium, while the upper section removes petroleum spirit components using a second scrubbing medium. This consolidation eliminates the need for separate oil scrubbing columns while maintaining comprehensive purification effectiveness.
Solution Approach 2:
The single scrubbing column is segmented into distinct functional sections: a lower section for heavy oil and particle removal, and an upper section for petroleum spirit component removal. Each section uses appropriately selected scrubbing media and operating conditions optimized for its specific purification function, allowing complex purification tasks to be accomplished in one integrated unit.
2Reliability
If multiple scrubbing steps are used for cracking gas purification, then purification completeness is improved, but operational complexity increases
Solution Approach 1:
Multiple scrubbing functions are merged into a single continuous operational unit. The scrubbing column operates as one integrated system where cracking gas passes sequentially through different sections with different scrubbing media, achieving complete purification in a single operational step rather than requiring multiple separate scrubbing steps.
Solution Approach 2:
The scrubbing column is designed as a multi-functional unit that simultaneously performs heavy oil removal, solid particle removal, and petroleum spirit component removal. This universal design allows one piece of equipment to handle all purification requirements, significantly reducing operational complexity compared to specialized equipment for each function.
3Device complexity
If a single scrubbing column is used to eliminate the primary oil fractionator, then apparatus requirements are reduced, but purification efficiency may worsen
Solution Approach 1:
The scrubbing column is segmented into functional sections with optimized contact conditions for each purification task. The lower section uses a first scrubbing medium with specific properties for heavy oil removal, while the upper section uses a second scrubbing medium for petroleum spirit component removal. This segmentation ensures high purification efficiency within the single column by creating optimal local conditions for each function.
Solution Approach 2:
Different sections of the scrubbing column operate with different parameters including varying scrubbing medium types, temperatures, and flow rates. These parameter changes are optimized for each specific purification function, allowing the single column to achieve purification efficiency comparable to or exceeding that of multiple separate 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 approach reduces apparatus requirements, allows for in-situ production of petroleum spirit as a scrubbing medium, and enables efficient removal of heavy oil, petroleum spirit components, and solid particles in a single column, thereby simplifying the purification process and reducing operational costs.
Implementation Method 1
the hydrocarbon-containing feed is fed together with steam into a cracking furnace of an appropriate apparatus and heated there by means of thermal radiation
Implementation Method 2
the cracking gas is directly introduced and purified in countercurrent flow through the column's sections, with the petroleum spirit-rich fraction removing heavy oil components and solid particles
Implementation Method 3
water-rich fraction removing petroleum spirit components in the upper section
Data Source
AI summary
In a process for producing olefins, a hydrocarbon-containing feed is fed into a cracking furnace where relatively long-chain hydrocarbons of the hydrocarbon-containing feed are cracked at least partly to form shorter-chain olefins, encompassing ethylene and propylene. Cracking gas (1) formed during cracking is conveyed in succession through an upper section (11) and a lower section (12) of a scrubbing column (10) in countercurrent to a liquid scrubbing medium (43, 31), is proposed. A fraction (43) rich in petroleum spirit is used in the lower section (11) of the scrubbing column (10) and a water-rich fraction (31) is used in the upper section (11) of the scrubbing column (10) as scrubbing medium (43, 31). A plant configured for carrying out the process is likewise provided by the present invention.