Needle Coke Production Without Hydrotreating for Low CTE
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Solution Overview
Problem
Conventional processes for producing needle coke require hydrotreating, which increases capital and operational expenses (CAPEX/OPEX) and leads to catalyst poisoning and feed material loss, while adding inorganic additives to control thermal expansion coefficient (CTE) raises ash content, making it challenging to produce high-quality needle coke efficiently.
Innovation Solution
A process involving mixing unhydrotreated first and second feeds, heating them to specific temperatures, passing through a delayed coker furnace, and treating the separated coke with superheated steam followed by quenching with water to produce needle coke with low sulfur content and controlled CTE without hydrotreatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrotreating is used to reduce sulfur and nitrogen in feed, then needle coke quality is improved, but capital and operational expenses increase and catalyst poisoning occurs
Solution Approach 1:
The patent extracts and removes the hydrotreating step from the needle coke production process. By directly coking unhydrotreated feeds containing sulfur, nitrogen, and metals, the process eliminates the need for complex hydrotreating units and catalysts, thereby reducing capital and operational expenses while avoiding catalyst poisoning issues.
Solution Approach 2:
Instead of the conventional approach of treating feeds to remove impurities before coking, this patent inverts the approach by directly coking unhydrotreated feeds and then removing impurities from the coke product through washing and treatment steps. This reversal eliminates the need for pre-treatment complexity while achieving the desired product quality.
2Manufacturing precision
If inorganic additives are added to control thermal expansion coefficient, then CTE is reduced, but ash content increases
Solution Approach 1:
The patent converts the harmful effect of sulfur and other impurities in unhydrotreated feeds into a benefit by using them to naturally control the thermal expansion coefficient. Instead of adding inorganic additives that increase ash content, the process utilizes the inherent composition of the feed and coking conditions to achieve the desired CTE, thereby avoiding ash content increase.
Solution Approach 2:
The patent changes the operating parameters of the coking process, specifically temperature, pressure, and residence time, to control the thermal expansion coefficient without adding inorganic additives. By optimizing these parameters, the process achieves the desired CTE while maintaining low ash content in the needle coke product.
3Manufacturing precision
If hydrotreating is used to treat heavy fraction, then sulfur and nitrogen are reduced, but feed material loss increases due to lighter component formation
Solution Approach 1:
The patent extracts and removes the hydrotreating step that causes feed material loss. By directly coking unhydrotreated heavy fractions, the process avoids the formation of lighter components through hydrogenation, thereby preventing feed material loss while still achieving the desired reduction in sulfur and nitrogen content in the final coke product through post-coking treatment.
4Productivity
If conventional delayed coker is used to maximize needle coke yield, then productivity is improved, but only a fraction of coke meets premium quality standards
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different portions of the coke product. Through controlled coking conditions and post-coking washing/treatment steps, the process ensures that the portion of coke meeting premium quality standards is optimized, while maximizing overall yield by accepting and treating lower quality portions separately.
Solution Approach 2:
The patent performs preliminary actions by pre-heating and pre-treating the feed in specific ways before coking to optimize the formation of premium quality needle coke. By controlling the initial conditions and feed preparation, the process increases the fraction of coke that meets premium quality standards while maintaining high 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
The process achieves high-quality needle coke with low sulfur and CTE, reducing CAPEX/OPEX by eliminating hydrotreatment and maximizing yield, while maintaining the desired properties without using expensive additives.
Implementation Method 1
heating the fractionator to obtain a blend... passing the blend to a delayed coker furnace and the furnace is heated to a second predetermined temperature to obtain a heated coker feed
Implementation Method 2
The separated coke in the coke drum is treated with a superheated steam for a second predetermined time period
Implementation Method 3
The treated coke is quenched with water to obtain the needle coke
Data Source
AI summary
The present disclosure relates to a process for the production of needle coke in a delayed coker plant. The needle coke so obtained by the process of the present disclosure has a co-efficient of thermal expansion (CTE) of less than 1.2×10−6/° C. The process of the present disclosure eliminates the step of hydrotreating of the first feed and second feed for the production of good quality coke. The process of the present disclosure maximizes the production of the needle coke having low CTE and low sulfur content in the delayed coker coke drum.