Case Study - At Total Petrochemicals polyethylene production plant in Antwerp, the facility wanted to find a way to increase its reliability and stability at the plant. At issue were two boilers equipped with single loop individual controllers. Unfortunately one boiler was not able to control the steam header pressure automatically without tripping on load upsets.

As part of a boiler revamp project, Total Petrochemicals turned to Honeywell to help design a state-of-the-art boiler/combustion control system according to its latest standards and philosphy.

In addition to new transmitters, valves , wiring, and a variable speed drive on the air fan, Total replaced the existing control system with a Honeywell Experion Process Knowledge System (PKS) controller and also installed a Honeywell SIL 3 Safety Management system for burner management and boiler/burner emergency shutdown.

After loop testing and commissioning the boiler control strategies were tuned within two days. Stress tests were performed in order to verify the load rejection capabilities and stability of the automation system and fire tube boiler unit sucessfully. Due to the increased stability, Total is now able to use the fire tube boiler as its preferred pressure controlling unit. Other benefits achieved with Honeywell's automation solutions:

• Increased steam production reliability and stability which has a positive impact on the chemical production quality and quantity
• Completed project on time and within budget
• Tight air flow control using a Variable Speed Drive and reduced excess air levels from (5-6 to 1.5 -2 vol %)

Background

Total Petrochemicals, one of the world's leading petrochemicals companies, does business in Europe, the U.S., the Middle East and Asia. The company has its head office in Brussels (Belgium) and employs nearly 6,500 people worldwide. Its main product is polymers, which are used to make a host of plastic products that are indispensable to daily life in today's world.

Total Petrochemicals brings together all of the Total Group's petrochemicals activities and helps to valorize hydrocarbon derivatives - naphtha, butane and distillates - mainly produced by the group's refineries. Located in Antwerp, Total Petrochemicals operates a high density polyethylene production plant with an overall capacity of 510,000 tons per year and is capable of producing a large number of polyethylene grades using a variety of systems and producing bimodal resins. This plant receives the bulk of its feedstock from the nearby Fina Antwerp Olefins facility.

Challenge

At Total Petrochemicals' Antwerpen facility, two boilers produce medium pressure steam for process heating. The fire tube boilers are equipped with single loop individual controllers and one boiler did not withstand the test of time - not once in the last decade was it able to control the steam header pressure automatically without tripping on load upsets - costing the company both time and money.

As part of a project organization, Total Petrochemicals Antwerpen implemented a boiler revamp project which would involve new instruments to help make the facility more stable and reliable; thereby increasing both the quality and quantity of the products it produces.

"We had to look at this project in various ways and find a way to positively impact our organization in three key areas: operationally, financially and environmentally," said Bert Jacobs, Automation Project Manager, Total Petrochemicals.

Solution

Total Petrochemicals worked with Honeywell and selected its Experion controller and Safety Management System to help drive the boiler revamp. The project involved installing new transmitters,valves wiring, installation of a variable speed drive on the air fan and replacing the existing controllers with a Honeywell Experion controller and a Honeywell SIL 3 Safety Management system for burner management and boiler/burner emergency shutdown.

"We selected to work with Honeywell based on their utility control capabilities and experience in this field," said Jacobs. "Honeywell developed and designed a state-of-the-art boiler and combustion control that met our latest standards and operating philosophy.

"The results were beyond our expectations as step wise load disturbances (60 % of MCR) were imposed on the unit upwards and downwards, resulting in a relative small header pressure change of only 0.4 bar," continued Jacobs.

"In the past the unit would have tripped trying to deal which such upsets," Jacobs said. Due to the increased stability of Total Petrochemicals fire tube boiler, the company is now using it as its preferred pressure controlling unit. The installation of the variable speed drive and reduction of excess air improved the efficiency of the unit.

"Working with Honeywell we were able to complete the project on time and improve our chemical production while still saving costs," Jacobs said. Currently Honeywell has provided the same excellent services for our new boiler project. Although the unit is more complex (burning three different fuels simultaneously in new low NOx burners) the results are "astonishing" and significantly reducing the carbon footprint of the facility, Jacobs concluded.