Foundation Fieldbus Modernization of a fertilizer complex using Foundation Fieldbus with diagnostic functions
To update their fertilizer production in Alexandria, Egypt, the Abu Qir Fertilizers and Chemical Industries Company (AFC) assigned the revamping of their existing plants to Uhde Services. In cooperation with Honeywell Process Solutions as supplier for control systems and physical-layer-specialist Turck, Uhde Services converted the complex to Foundation Fieldbus, including detailed diagnostic functions for a comprehensive asset management system.
The Abu Qir Fertilizers and Chemical Industries Company (AFC) in Alexandria, Egypt, is one of the leading manufacturers of nitrogenous fertilizers in Egypt, Africa and the Middle East. The company has more than 3,300 employees and relies on international standards during production and quality management, including ISO 9001/2000. To guarantee environmentally friendly and efficient production, the plants in Alexandria are continuously being upgraded and optimized. The use of modern automation solutions for ammonia plants is critical in the fertilizer industry because it provides increases in production and energy savings.
“With the Abu-Qir-revamp-project, a large fertilizer plant in North Africa is being converted into an ultra-modern automation solution for the first time,” says Dr Bernd Jordan, Head of Electrical and Instrumentation at Uhde Services. The service provider Uhde, a fully owned subsidiary of Thyssen Krupp, develops individual concepts for industrial plants worldwide for modernization and increased production, for maintenance, compliance with environmental standards, and increased cost and performance efficiency. The focus of Uhde lies with the power plant technology, mineral oil processing, chemical, as well as the petrochemical industry.
Because of the geographical position of the fertilizer complex, the Foundation Fieldbus wiring as well as the Foundation Fieldbus system components must meet very high standards. The ambient temperature usually lies between 3 and 45 °C and the surface temperature can rise up to 75 °C in direct sunlight. A relative humidity of about 85 percent as well as the chemical and the mechanical demands through urea, ammonium nitrate, dust and sand complete the profile of requirements.
The revamp-project can be divided into two parts: Foundation Fieldbus loops for measurements and process control as well as ESD-loops for fail safe plant monitoring. All in all, 350 devices in hazardous classified areas and 1,050 devices in unclassified areas had to be connected via Foundation Fieldbus, divided into 220 segments — 60 each in the ammonia plant, the nitric acid plant and the utilities and factory services, plus 40 more for the visualization. After a search for a suitable solutions partner for the Foundation Fieldbus installations in Abu Qir, the general contractor Uhde Services and the operator of the plant selected Turck, the sensor, fieldbus, and interface specialist. “Turck wasn’t just able to provide us with an extensive Foundation Fieldbus portfolio, but also with detailed diagnostic functions that make a new Foundation Fieldbus installation all the more efficient,” says Markus Mahlandt, Project Engineer E&CI Engineering Uhde Services.
To supply and monitor all 220 segments, Turck delivered 60 preconfigured diagnostic-power-conditioner-systems (DPC) in control cabinets. The DPC-systems supply FF H1-segments with power and offer comprehensive diagnostic capabilities for monitoring, which allow a plant-wide asset management. The start-up of a fieldbus plant is already supported by the DPC-system. During operation, the solution even recognizes gradual changes within single fieldbus segments over an extended period of time. So disturbances or failures that develop slowly can be prevented.
One DPC-system can supply up to 16 segments redundantly with up to 800 mA output current and 30 VDC output voltage. It consists of one or more DPC-49-4RMB module racks with up to eight DPC-49-IPS1 power supply modules and one DPC-49-ADU diagnostic module. Per module rack, up to four H1-segments can be operated and monitored redundantly. The diagnostic data from the H1-segments can be transferred via a FF-HSE-field device DPC-49-HSEFD/24VDC to a higher level asset-management-application — in this case an Experion PKS from Honeywell.
165 JBBS junction boxes and 110 multi-barriers from Turck are responsible for the safe and secure connection of the field devices to the DPC-systems in Abu Qir. The eight channel JBBS junction boxes are equipped with an adjustable short circuit limit (30, 35, 45 and 60 mA). Common shielding concepts can be realized with the help of two switches on the circuit board, and a terminating resistor for the bus can be switched on. The enclosure is IP67 rated and made of powder coated aluminum with a breather to prevent internal condensation. Despite their high ingress protection rating, Turck placed the junction-boxes in additional protective housings to ensure their ability to defy the harsh ambient conditions.
Multi-barriers MBD49-T415/Ex are applied for connection to field devices in hazardous classified areas. The multi-barriers increases the maximum number of field bus nodes per segment up to 32. The number of nodes is extended by the explosion protected fieldbus supply which can be daisy chained from multi-barrier to multi-barrier in Zone 1. Each fieldbus node in Zone 0 and Zone 1 is supplied by one of the four intrinsically safe and galvanically isolated outputs of each multi-barrier. Galvanic isolation exists between the trunk line and the output circuits as well as between the four output circuits themselves. For the customer, the use of multi-barriers has clear cost advantages. All field devices in a single fieldbus segment can be operated in the hazardous classified area; there are no costs for additional bus couplers, or a new segment card with its integration and parameterization. There is no need for additional supply wiring as the power supply of the multi-barriers takes place over the bus with the support of Turck.
Even with the complete package from Turck, there were a few obstacles to overcome at the beginning of the project, which contained 200 kilometers of fieldbus lines. “It is normal that some problems arise when it comes to a project of this size,” Dr Jordan explains. But ultimately the first two reconstruction phases were completed on time and to the satisfaction of the operator.