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A world-class steam cracker has a production capacity of over 700,000 tons of ethylene per year. It transforms naphtha and other refining feedstocks into olefins by cracking the molecules at high temperatures.
Debottlenecking steam superheat issues in a steam cracker
The olefins obtained will mainly be used by the companies present on site. The latter will transform them into raw materials for the production of everyday objects such as bottles, packaging, toys, detergents and automotive equipment.
The challenge — Steam superheat reduction
The plant was experiencing periods of operation with an excessive reduction in steam superheat resulting from inefficient heat transfer in the convection sections. A serious consequence was the excessive moisture formation in the turbine causing water erosion of blades, nozzle partitions, diaphragm throat surfaces, etc.
It is vital to keep the convection sections in steam cracking furnaces in a clean condition, not only for the sake of energy efficiency, fuel savings and CO2 emission reduction but also forsafe turbine and cracked gas compressor operation.
Regular maintenance is essential to ensure optimum performance and production capabilities, especially for the convection sections of the cracking furnaces.
In use, at the high temperatures required by the process, finned convection section tubes become fouled by dust generated by the gradual deterioration of radiant section refractories.
Historically, in 2015 and 2018, traditional water cleaning — allowing water to cascade over the convection section tubes from top to bottom — had been unsuccessful, showing no signs of improved heat transfer.
Integrated Global Services (IGS) experience
Debottlenecking steam superheat issues in a steam cracker
Figure 2 — TubeTech’s convection section cleaning rover
IGS offers two different convection section tube cleaning services.
- TubeTech’s fired heater convection section fouling removal service, undertaken during shutdowns, is a proven turnkey solution that guarantees to remove 90%+ fouling, restoring fired heater performance and reducing CO2 emissions and fuel consumption (Figure 2). The robotic system can access even the most difficult-to-reach convection banks. It is remotely controlled by an experienced technician and the engineered lance penetrates deep between each tube row to remove the toughest fouling.
- 90%+ fouling removed guarantee
- 2-5% increase in total fuel efficiency*
- Up to 5% reduction in CO2 emissions*
- Payback Period within 2-3 months
* Average results reported by TubeTech clients
Debottlenecking steam superheat issues in a steam cracker
Figure 3 — Convection section bundle before and after Hot-Tek cleaning
- Hot-tek™ — Hot Convection Cleaning (HCC) process removes convection section tube fouling and scale during furnace operation (Figure 3). The tube cleaning process uses consumable abrasive media projected through specially designed application lances to blast away years of accumulation, while the heater is in service.
- In some applications, Cetek’s Lancescope™ system is used to see hard-to-reach areas.
- In addition, it is possible to safely create engineered access ports to facilitate the TubeTech system or the hot convection section cleaning process and for future access.
Debottlenecking steam superheat issues in a steam cracker
In 2020, TubeTech’s service was used on one furnace, with the following results:
- Steam production increase of 4 tonne/hr
- Superheated steam temperature gain of 35 °C
- Desuperheating active (according to the designed flowsheet)
Debottlenecking steam superheat issues in a steam cracker
In 2024, TubeTech’s service was used on a second furnace, with the following results:
- Steam production increase of 4 tonne/hr
- Superheated steam temperature gain of 40 °C (from 420 °C to 460 °C)
- Desuperheating active (according to the designed flowsheet)
In 2024, Hot-tek’s HCC service was used on a third furnace, with the following results:
- Superheated steam temperature gain of 60 °C (from 415 °C to 475°C)
- Desuperheating active (according to the designed flowsheet)
In each IGS application, the return on investment was immediate. The IGS services have been recommended internally to sister companies.
For more information, visit integratedglobal.com.
