Coking Furnace for Refinery Heavy Oil Processing
A coking furnace is crucial for refinery heavy oil upgrading. It is designed to heat heavy oil and vacuum residue to the required temperature before the coking process.
At Gelan, we design and manufacture refinery coking furnaces to improve heat distribution, reduce premature cracking inside the furnace, and support longer run length under severe operating conditions.
- ≤ ±10–15°C tube wall temperature deviation
- Up to 6–12 months continuous run length
- Optimized heat flux distribution for improved temperature uniformity
- Designed and fabricated to ASME and API 560 standards
What Does a Coking Furnace Do in Heavy Oil Processing
In a refinery, crude oil is first separated through atmospheric and vacuum distillation. The remaining heavy residue cannot be economically upgraded by distillation alone.
A coking furnace heats this residue to the required temperature before the coking stage, helping convert it into lighter, higher-value products such as gas, naphtha, and diesel.
Convert low-value residue into higher-value saleable products
Improve overall yield from the same crude input
Reduce heavy residue sent to low-margin fuel use
Support more efficient downstream residue upgrading
Where the Coking Furnace Fits in the Refinery Process
After atmospheric and vacuum distillation, heavy residue is routed to the coking section for further upgrading.
The coking furnace is positioned before the coking drums. It heats the residue to the required temperature so it can enter the coking stage under stable conditions.
Typical Technical Specifications of a Coking Furnace
| Parameter | Gelan Typical Range | Importance |
|---|---|---|
| Operating Temperature | 480–520°C | Affects cracking conditions and material selection |
| Feedstock | Vacuum residue / heavy oil | Determines fouling tendency and furnace design complexity |
| Tube Wall Temperature Deviation | ≤ ±10–15°C | Lower deviation helps reduce hotspot risk |
| Continuous Run Length | 6–12 months | Longer cycles mean fewer shutdowns |
| Heat Flux | Customized by design | Impacts heat distribution and cracking stability |
| Tube Material | Alloy steel (e.g. HK, HP) | Selected based on temperature and corrosion resistance |
| Design Standard | ASME / API 560 | Can be supplemented to meet project specifications and client requirements |
*These parameters are not fixed. In real projects, furnace design must be adjusted based on feed quality, fouling tendency, and required operating cycle.
How Gelan Coking Furnace Design Solves Heavy Oil Challenges
Reducing Coke Build-Up in Heavy Residue Service
Heavy residue feeds tend to form coke rapidly on tube surfaces. Once coke builds up, heat transfer drops and the furnace needs to be shut down for decoking.
Gelan approach:
- Heat flux distribution designed to avoid local high-temperature zones
- Tube surface temperature controlled to slow down coke formation
Typical performance:
- Lower coking rate under heavy residue conditions
- Longer decoking interval depending on feed quality
Residence Time Control to Prevent Early Cracking
If the feed stays too long in the furnace tubes, cracking can start inside the furnace instead of in the coking stage, leading to unstable operation.
Gelan approach:
- Tube length and flow path designed to control residence time
- Heat input balanced to avoid overexposure of feed inside tubes
Typical performance:
- Reduced risk of premature cracking inside furnace tubes
- More stable feed condition entering the coking stage
Stable and Uniform Temperature Control
Uneven temperature distribution can create hotspots, damage tubes, and accelerate coke formation.
Gelan approach:
- Burner layout optimized for even radiant heat distribution
- Tube arrangement designed to improve temperature uniformity
Typical performance:
- ≤ ±10–15°C tube wall temperature deviation
- Reduced local overheating risk
Heat Load Distribution and Energy Efficiency
Poor heat load distribution not only affects operation stability but also increases fuel consumption.
Gelan approach:
- Heat duty and heat intensity balanced across the furnace
- Combustion system designed for stable and efficient operation
Typical performance:
- More efficient fuel utilization under stable operation
- Reduced energy loss caused by uneven heating
Tube Life Under High Temperature and Fouling Conditions
Furnace tubes operate under high temperature and fouling conditions, which directly affect maintenance cost and shutdown frequency.
Gelan approach:
- Tube material selected based on temperature and corrosion conditions
- Design optimized to reduce thermal stress and local overheating
Typical performance:
- Extended tube service life under severe operating conditions
- Lower risk of premature tube failure
Processing Capacity and Operational Stability
For large-scale refinery projects, the furnace must handle required throughput without sacrificing stability.
Gelan approach:
- Furnace size and configuration designed based on project capacity
- Flow distribution optimized to maintain stable operation at scale
Typical performance:
- Stable operation at design capacity
- Reduced operational fluctuation under varying load
Where Delayed Coking Furnaces Are Used
Typically used in industries where heavy oil and residue require further upgrading.
Residue Coking Furnace Projects Delivered by Gelan
Residue Coking Furnace for 1.6 Million TPA Delayed Coking Unit
Project Background:
Coking furnace supplied for a 1.6 million TPA delayed coking unit. The project handled vacuum residue with high fouling tendency.
Key requirement:
Keep the unit running at design capacity with fewer fouling problems and fewer shutdowns.
Gelan support:
- Customized furnace design for heavy residue service
- Heat load adjusted to reduce local over-firing
- Tube layout optimized to better control residence time
Result:
- Supported stable operation of the 1.6 million TPA unit
- Reduced the impact of tube fouling on throughput
- Helped the unit run more steadily with fewer interruptions
- Improved reliability during continuous operation
Related Equipment in the Delayed Coking Process
A coking furnace works together with other key equipment to support stable residue processing and product conversion.
Shell & Tube Heat Exchangers
Recovers heat from process streams around the furnace. Supports temperature control and improves heat efficiency.
Waste Heat Boiler
Recovers heat from high-temperature flue gas of the furnace. Helps reduce fuel consumption and improve energy use.
Atmospheric Furnace
Heats crude oil before primary separation. Provides atmospheric residue that is further processed into heavier fractions.
Vacuum Furnace
Heats atmospheric residue before vacuum distillation. Produces vacuum residue as the main feed for the coking furnace.
Fractionation Column
Separates cracked products after thermal processing. Handles the products generated from the coking stage.
Preheater
Raises feed temperature before entering the coking furnace. Helps reduce furnace load and stabilize heating.
FAQs About Coking Furnace
What is a coking furnace used for in a refinery?
It prepares the feed for further cracking and helps convert low-value residue into lighter products and petroleum coke.
What feedstock is typically processed in a coking furnace?
These feeds usually contain high asphaltene content and have a strong tendency to form coke during heating.
What are the main operating challenges of a coking furnace?
Common challenges include:
- Coke formation inside furnace tubes
- Uneven heat distribution and local hotspots
- Premature cracking before the coking stage
- Short run length due to fouling
These issues directly affect stability, maintenance frequency, and operating cost.
Why is residence time important in a coking furnace?
If the feed stays too long in the furnace, cracking may begin too early, leading to fouling and unstable operation.
What determines the run length of a coking furnace?
Run length mainly depends on:
- Feed quality and fouling tendency
- Heat distribution inside the furnace
- Tube temperature control
In most cases, coke buildup inside the tubes is the main limiting factor.
What temperature does a coking furnace operate at?
Typical operating temperatures are around 480–510°C, depending on feedstock and process conditions.
How can coke formation inside furnace tubes be reduced?
Coke formation can be reduced by:
- Controlling tube wall temperature
- Improving heat distribution
- Managing residence time
- Optimizing feed conditions
These measures help extend operating cycles and reduce shutdown frequency.
How do I choose the right coking furnace for my project?
The right furnace depends on your feed characteristics, fouling tendency, operating cycle, and required throughput.
For projects with heavy residue or severe operating conditions, working with an experienced manufacturer like Gelan can help you better match furnace design with your actual process requirements.
How does coking furnace performance affect refinery operation?
Furnace performance directly impacts:
- Unit run length
- Throughput stability
- Frequency of shutdowns
- Overall refinery profitability
Even small improvements in operation stability can significantly affect long-term performance.
Get a Coking Furnace Designed for Your Project
Talk to our engineers to discuss your process and get a coking furnace solution tailored to your project.