Carbon Adsorbent Pore Structure for Asphaltene Removal
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Solution Overview
Problem
Conventional steam cracking processes are hindered by non-volatile components like asphaltenes in hydrocarbon streams, leading to coking and reduced economic value, as existing methods for asphaltene removal are not effective in providing a suitable stream for cracking and have limitations in adsorbent life.
Innovation Solution
A process using a carbon-based adsorbent with specific pore size range (0.1 to 2.0 micrometers) and high oil adsorption number (at least 200) to effectively adsorb asphaltenes from hydrocarbon streams, producing an asphaltene-depleted stream that can be further processed in a steam cracking furnace, with the adsorbent being regenerable to extend its life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam cracking is used to process hydrocarbon feeds containing asphaltenes, then light olefins such as ethylene, propylene, and butene are produced, but coking occurs in the convection section causing costly shutdowns for cleaning
Solution Approach 1:
The patent applies preliminary action by removing asphaltenes from the hydrocarbon feed before it enters the steam cracking furnace. The adsorbent is placed in the feed line upstream of the furnace, where it pre-treats the feed by adsorbing asphaltenes and other non-volatile contaminants. This prevents coking in the convection section during subsequent cracking operations, allowing continuous operation without shutdowns for cleaning.
2Ease of manufacture
If asphaltenes are present in hydrocarbon feeds, then the feed can be processed, but asphaltenes reduce the economic value by rendering the feed less compatible for mixing with highly paraffinic streams and inducing precipitation
Solution Approach 1:
The patent applies the extraction principle by selectively removing asphaltenes from the hydrocarbon feed using an adsorbent material. The adsorbent extracts asphaltenes and other non-volatile contaminants from the feed stream, producing a cleaned feed that is compatible for mixing with highly paraffinic streams. This extraction process restores the economic value of the feed by eliminating the precipitation problem and improving mixability.
3Quantity of substance
If existing methods for asphaltene removal are used, then some asphaltene reduction is achieved, but they are not effective in providing a suitable stream for cracking and have limitations in adsorbent life
Solution Approach 1:
The patent applies porous materials by using an adsorbent with a specific porous structure characterized by a pore size distribution with a mode between 0.5-2.0 micrometers and a pore volume of at least 0.35 mL/g. This optimized porous structure provides effective asphaltene removal while maintaining adsorbent stability and longevity. The porous material achieves both high asphaltene capacity and extended adsorbent life, making the feed suitable for cracking operations.
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
The process achieves an asphaltene depletion of at least 70% by weight, enhancing the hydrocarbon stream's compatibility for cracking and extending the adsorbent's life, thereby improving the efficiency and economic viability of steam cracking.
Implementation Method 1
contacting said hydrocarbon stream with a carbon based adsorbent to adsorb said asphaltenes from said hydrocarbon stream
Data Source
AI summary
A process and adsorption vessel are provided for adsorbing asphaltenes from a hydrocarbon stream. Additionally, a process and adsorption vessel are provided for steam cracking a hydrocarbon stream containing asphaltenes by adsorbing asphaltenes from the hydrocarbon stream prior to steam cracking. Asphaltene adsorption is achieved through a carbon adsorbent having at least 25% of total pore volume provided by pores with pore diameter in the range of 0.1 to 2.0 micrometers and an oil adsorption number of at least 200.