Pitch Hydroprocessing Using Utility Fluid Diluent to Reduce Fouling
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Solution Overview
Problem
Existing processes for upgrading pitch are prone to fouling due to high molecular weight constituents and inorganic solids, leading to equipment degradation and operational challenges.
Innovation Solution
The process involves separating a vapor phase and liquid phase from a heated mixture, hydroprocessing the liquid phase to produce a first hydroprocessed product, and then further hydroprocessing a pitch-diluent mixture to reduce fouling by using a utility fluid as a diluent, which includes aromatic ring compounds, to prevent coke deposition and fouling within equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pitch is transported and processed through equipment, then pitch upgrading is achieved, but fouling occurs due to high molecular weight constituents and inorganic solids
Solution Approach 1:
A diluent is introduced as an intermediary substance to mix with the pitch, reducing the concentration of high molecular weight constituents and inorganic solids that cause fouling. This diluent acts as a mediator between the pitch and processing equipment, preventing direct contact between the fouling-prone pitch and equipment surfaces.
Solution Approach 2:
The concentration of pitch in the processing stream is changed by adding diluent, transforming the pitch from a concentrated, fouling-prone state to a diluted, fouling-resistant state. This parameter change (concentration reduction) directly addresses the fouling problem while maintaining pitch upgrading productivity.
2Productivity
If equipment is used for pitch transport and processing, then pitch conversion is achieved, but equipment degradation occurs due to fouling
Solution Approach 1:
The diluent serves as a protective intermediary that reduces direct interaction between pitch constituents and equipment surfaces, thereby preventing equipment degradation and extending equipment longevity while maintaining pitch conversion productivity.
Solution Approach 2:
The diluent provides beforehand cushioning by pre-mixing with pitch before processing, creating a fouling-resistant mixture that protects equipment from the harmful effects of high molecular weight constituents and inorganic solids before they can cause degradation.
3Productivity
If pitch is processed without dilution, then processing efficiency is maintained, but fouling and coke deposition increase
Solution Approach 1:
The concentration parameter of pitch is changed by adding diluent, reducing the concentration of coke-forming constituents to levels that prevent coke deposition while maintaining processing efficiency. This parameter modification allows continuous operation without frequent shutdowns for cleaning.
Solution Approach 2:
The diluent converts the harmful effect of concentrated pitch (coke deposition) into a beneficial outcome (fouling reduction). By adding the diluent, the high molecular weight constituents that would otherwise cause coke deposition are diluted to concentrations that prevent this harmful effect while maintaining pitch upgrading productivity.
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 effectively reduces fouling in equipment and hydroprocessing units, improving the efficiency and longevity of pitch upgrading processes by utilizing the utility fluid's hydrogen-donating properties to mitigate foulant formation.
Implementation Method 1
utilizing the utility fluid's hydrogen-donating properties to mitigate foulant formation
Implementation Method 2
separating a vapor phase product and a liquid phase product from a heated mixture
Implementation Method 3
A mixture of crude oil and water/steam can be heated in a convection section of a steam cracking furnace
Implementation Method 4
utilizes an ebullated bed of catalyst comprising alumina, Mo, and Co Ni, to hydrocrack heavy oil
Data Source
AI summary
In some examples, hydrocarbon feed and a diluent such as steam are mixed, and heated. A vapor phase product and a liquid phase product can be separated from the heated mixture. The liquid phase product can be hydroprocessed to produce a first hydroprocessed product. A pitch and one or more hydrocarbon products can be separated from the first hydroprocessed product. The pitch can be contacted with a diluent to produce a pitch-diluent mixture. The pitch-diluent mixture can be hydroprocessed to produce a second hydroprocessed product. A hydroprocessor heavy product and a utility fluid product can be separated from the second hydroprocessed product. The diluent can be or include at least a portion of the utility fluid product. The vapor phase product can be steam cracked to produce a steam cracker effluent. A tar product and a process gas that can include ethylene and propylene can be separated from the steam cracker effluent.