Hydroconversion and Coking Process for Anode Grade Coke Production
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Solution Overview
Problem
Crude oil refineries face bottlenecks due to increased use of heavier crudes, leading to decreased quality of petroleum coke and fuel-grade coke, with existing technologies often worsening coke quality by shifting from porous sponge coke to denser shot coke with higher impurities.
Innovation Solution
A process involving hydroconversion of residuum hydrocarbon feedstocks with hydrogen and a hydroconversion catalyst, followed by fractionation and delayed coking to produce anode grade green coke and distillate hydrocarbons, optimizing conditions to maintain high coke quality and reduce contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal coking processes use high-severity thermal decomposition to maximize conversion of heavy residuum feeds, then lower boiling hydrocarbon products are increased, but coke quality deteriorates with higher contaminant concentrations
Solution Approach 1:
The process segments the heavy residuum feedstock into different fractions through hydroconversion, separating the problematic high-contaminant portions from the valuable hydrocarbon components. This allows selective processing where contaminants are concentrated in specific streams that can be directed to coking, while cleaner fractions are processed separately to maintain coke quality.
Solution Approach 2:
Hydroconversion is performed as a preliminary action before coking to modify the feedstock composition. This pre-treatment reduces contaminant levels in the portions of feedstock that will become coke, while still allowing high-severity thermal decomposition to proceed for maximum hydrocarbon conversion.
2Adaptability or versatility
If technology improvements are implemented to handle plant capacity bottlenecks and feedstock compositional changes, then processing capability is enhanced, but coke quality shifts from porous sponge coke to denser shot coke with higher impurities
Solution Approach 1:
Different portions of the feedstock are treated differently through the hydroconversion process. The process creates local quality variations where some fractions are heavily processed to remove contaminants while others are preserved with minimal modification. This allows the coking unit to receive pre-treated feedstock that maintains the desired sponge coke morphology and low impurity content.
Solution Approach 2:
The hydroconversion process changes key parameters of the feedstock including contaminant concentration, molecular structure, and physical properties. By adjusting hydroconversion severity and conditions, the process can optimize feedstock quality for coking while maintaining high overall processing capability for heavier crude compositions.
3Productivity
If heavier crudes with higher concentrations of aromatic structures and contaminants are processed, then refinery throughput is increased, but coke value dramatically decreases due to lower quality
Solution Approach 1:
The hydroconversion process extracts and removes contaminants and undesirable components from the heavy residuum feedstock before coking. This extraction of harmful substances allows the coker to produce high-value anode-grade coke while the refinery maintains high throughput by processing heavier crudes. The removed contaminants are separated into distinct streams that do not affect coke quality.
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 effectively upgrades residuum feedstocks to produce high-quality anode grade green coke and distillate fuels, maintaining coke value and reducing undesirable contaminants, thereby addressing the bottleneck and quality issues in crude oil refineries.
Implementation Method 1
contacting a residuum hydrocarbon and hydrogen with a hydroconversion catalyst in an residuum hydroconversion reactor system
Implementation Method 2
thermal coking processes employ high-severity, thermal decomposition (or 'cracking') to maximize the conversion of very heavy, low-value residuum feeds to lower boiling hydrocarbon products of higher value
Implementation Method 3
The resulting hydrocarbons and other products move from the coking vessel to a fractionator in vapor form
Data Source
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AI summary
A process for upgrading residuum hydrocarbon feedstocks that may include: contacting a residuum hydrocarbon and hydrogen with a hydroconversion catalyst in a residuum hydroconversion reactor system; recovering an effluent from the residuum hydroconversion reactor system; separating the effluent to recover two or more hydrocarbon fractions including at least a vacuum residuum fraction and a heavy vacuum gas oil fraction; combining at least a portion of the heavy vacuum gas oil fraction and at least a portion of the vacuum residuum fraction to form a mixed heavy hydrocarbon fraction; feeding at least a portion of the mixed heavy hydrocarbon fraction to a coker; operating the coker at conditions to produce anode grade green coke and distillate hydrocarbons; recovering the distillate hydrocarbons from the coker; fractionating the distillate hydrocarbons to recover hydrocarbon fractions including a light distillates fraction, a heavy coker gas oil fraction, and a coker recycle fraction.