Coke Drum - Temperature Monitoring

Wireless temperature measurement solution makes modernizing operations and maintenance of delayed coker unit affordable.

Delayed cokers are a type of coker unit whose process consists of multiple coke drums that receive heavy oil feed which has been heated to its thermal cracking temperature. Lighter hydrocarbons are produced and sent to a fractionator while solid coke is deposited in the drum. Once the drum is full, production is switched to another drum and the original drum must be cleaned/decoked.

Challenges

Coking is one of the most temperature intensive processes in a refinery and many temperature measures are required to provide the best control. Depending on the capacity, the number of coke drums in operation can vary from 2-8 drums. Each coke drum can require up to 24 temperature points to be monitored. A coker tube furnace is used to heat heavy oil that feeds the coke drums. The heater provides all the heat in the process. The output temperature of the furnace is typically around 500 degrees. 

Without having the right amount of temperature measurements, refinery coker units may experience the following situations:

• Increased energy costs due to unoptimized fuel consumption.
• Furnace fouling leading to added maintenance and downtime.
• Increased variability in drum cycle times.
• Reduced throughput and production quality.

However, many refineries find it difficult to add temperature measurements due to costs and lack of available control system IO.

Solutions

To move forward with their coker optimization project, a North American refinery turned to Yokogawa’s ISA100 industrial wireless solution for their temperature measurement needs.  
Yokogawa YTMX580 multi-input temperature transmitters were installed on each coker drum as well as the furnace. Each of these accepts eight temperature inputs, greatly reducing the quantity of transmitters required for the project.

The field wireless access point was installed on the control room located 600m from the coker unit with dense obstructions. Two repeaters were used to establish redundant communication paths between the measurement devices and the field wireless access point. The wireless temperature data was easily and cost effectively integrated with refinery control system using Modbus communication.

Key Benefits

• Avoided costs of traditional instrumentation and control system IO expansion.
• Improved temperature control in the coker furnace simultaneously reduced fuel consumption and furnace maintenance.
• Increased coker unit throughput due to less downtime and better coke drum cycle time.