Anode Grade Coke Production from High Sulfur Crude
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Solution Overview
Problem
The challenge lies in producing anode-grade coke from high sulfur crude oils, as existing refining methods, such as hydrotreating, alter the physical characteristics of the residue, making it unsuitable for anode manufacturing and limiting the use of feedstocks to low sulfur and metals content virgin residues.
Innovation Solution
A refining process that involves hydroprocessing a portion of the atmospheric distillation tower bottoms to reduce sulfur content, followed by blending with vacuum distillation tower bottoms and using a solvent deasphalting unit to create a synthetic stream for the anode coking unit, optimizing the quality and economics of the coke production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrotreating is applied to reduce sulfur content in crude oil residue, then sulfur content is reduced, but physical characteristics of the residue are altered making it unsuitable for anode manufacturing
Solution Approach 1:
The crude oil processing is divided into separate streams: a hydroprocessed stream for sulfur removal and a non-hydroprocessed stream for preserving physical characteristics. These streams are then blended in specific ratios to produce feedstock that meets both sulfur content requirements and physical characteristics requirements for anode coke production.
Solution Approach 2:
Different portions of the crude oil residue are treated differently according to their intended use. The hydroprocessed portion undergoes severe treatment to remove sulfur, while the non-hydroprocessed portion maintains its original physical characteristics. The final blend achieves local optimization of both properties in the feedstock supplied to the coking unit.
2Object-affected harmful factors
If severe hydroprocessing is applied to high sulfur crude to produce anode grade coke, then sulfur content is reduced, but process cost and catalyst consumption increase
Solution Approach 1:
Instead of applying severe hydroprocessing to 100% of the crude oil residue, only a portion (e.g., 20-50%) is hydroprocessed to the extent required to meet sulfur specifications. The remaining portion is blended in, reducing the overall hydrogen consumption, catalyst usage, and operating costs while still achieving the required sulfur content in the final anode grade coke product.
3Productivity
If hydroprocessing is applied to increase anode grade coke yield, then sulfur content is reduced, but catalyst life is reduced due to increased severity
Solution Approach 1:
The feedstock processing is segmented into hydroprocessed and non-hydroprocessed portions. The hydroprocessed portion benefits from sulfur removal that improves coking efficiency and anode grade coke yield, while the non-hydroprocessed portion does not expose catalyst to severe conditions, thereby extending catalyst life. The blended approach optimizes both productivity and catalyst durability.
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 allows for the production of anode-grade coke with reduced sulfur and metals content, while reducing the severity and cost of hydroprocessing, extending catalyst life, and increasing the yield of valuable coke products.
Implementation Method 1
Hydroprocessing involves reacting the distillate products and at times residue from distillation with hydrogen in the presence of a catalyst to remove sulfur.
Implementation Method 2
a solvent deasphalting unit to create a synthetic stream for the anode coking unit
Data Source
AI summary
Methods and systems for producing anode grade coke are disclosed, which allow anode grade coke to be produced from crude oil having a high sulfur content. A fraction of the resid is hydrotreated while another fraction of the resid is treated in a solvent deasphalting unit. A synthetic stream is provided by blending hydrotreated resid with one or more streams from the deasphalting unit. The synthetic stream is fed to an anodic coker unit.