Needle Coke Process With Asphaltene Separation and Selective Hydrocracking
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Solution Overview
Problem
Existing methods for producing needle coke and aromatic chemicals from petroleum residues suffer from low yield, production of low-value by-products, and fail to effectively reduce ash content, leading to unsuitable coke quality for graphite electrodes.
Innovation Solution
An integrated process involving stream separation, solvent separation of refractory asphaltene compounds, and selective hydrocracking is employed to produce high-quality needle coke and aromatic chemicals from Pyrolytic Fuel Oil (PFO) and Clarified Oil (CLO), utilizing a tailored feed blend to minimize ash content and maximize aromatic production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal cracking process is used to produce needle coke from petroleum residues, then needle coke is obtained, but ash content is high and quality is unsuitable for graphite electrodes
Solution Approach 1:
The patent extracts and removes harmful components (asphaltenes and heavy residues) from the feedstock before thermal cracking through solvent extraction and separation processes. This pre-removal of impurities prevents ash formation in the final coke product, resolving the contradiction between obtaining needle coke and reducing ash content.
Solution Approach 2:
The patent performs preliminary treatment of the feedstock including solvent extraction, fractionation, and removal of asphaltenes before the thermal cracking process. This preliminary action prepares a purified feedstock that will produce low-ash needle coke, addressing the quality issue before the main cracking process occurs.
2Productivity
If conventional coking process is used, then needle coke is produced, but yield is low and low-value by-products are generated
Solution Approach 1:
The patent applies different processing conditions to different fractions of the feedstock. Lighter fractions are processed under conditions optimized for coke production, while heavier fractions are processed separately to maximize aromatic chemical yield. This localized optimization of processing conditions for different feedstock components improves both coke yield and by-product value.
Solution Approach 2:
The patent changes key process parameters including temperature profiles, residence times, and solvent types to optimize both coke yield and aromatic production. By adjusting these parameters across different process stages and units, the patent simultaneously improves productivity and reduces loss of valuable substances.
3Object-affected harmful factors
If feedstock is processed without stream separation, then processing is simpler, but ash content cannot be reduced and coke quality deteriorates
Solution Approach 1:
The patent segments the feedstock into different streams based on boiling range and composition (light fractions, heavy fractions, asphaltenes) through fractionation and solvent extraction. Each segment is then processed appropriately, with impurity-rich streams being separated and treated differently from clean streams, enabling effective ash content reduction through systematic separation.
Solution Approach 2:
The patent uses solvents as intermediary substances to facilitate the separation of asphaltenes and heavy residues from the feedstock. These solvents act as mediators that selectively dissolve or precipitate different components, enabling effective separation and removal of ash-forming materials while maintaining process feasibility.
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 high-yield production of needle coke with low ash content and enriched C7-C9 aromatics, improving the quality of coke suitable for graphite electrodes while simultaneously producing valuable aromatic chemicals.
Implementation Method 1
routing a Clarified Light Oil (CLO) stream (1) through a CLO Separator Column (2) to obtain a first stream (3) having boiling range below 350°C, a second stream (4) having boiling range between 350-500°C and a third stream (5) having boiling range above 500°C
Implementation Method 2
the third stream (5) is mixed with a fresh solvent stream (6) and a recycled solvent stream (13) and routed to a mixer (7) to obtain a mixed stream (8). routing the mixed stream (8) through an Asphaltene separator (9)
Implementation Method 3
the solvent rich stream (10) is routed to a Recovery Column (11) to obtain the recycle solvent stream (13) and a Purified CLO fraction stream (12)
Implementation Method 4
routing a Pyrolytic Fuel Oil (PFO) stream (29) through a PFO Separator Column (30) to obtain a fourth stream (31) having boiling range below 350°C and a fifth stream (32) having boiling range above 350°C
Data Source
Figure 1
AI summary
The present disclosure provides a process for preparing a needle coke or a crystalline coke from aromatic rich hydrocarbon streams. The process includes preparing a needle coke or a crystalline coke from Pyrolytic Fuel Oil (PFO) and Clarified Oil (CLO) stream along with Purified fraction of CLO after solvent separation of refractory asphaltene compounds while the low boiling fractions separated from PFO and light gasoil (LGO) from the thermal cracking section are selectively hydro cracked to produce high value aromatic chemicals.