PROCESS EQUIPMENT


Art of engineering: Pörner modernizes melamine plants for LAT Nitrogen


Three and a half years EPCM project: Innovative wastewater treatment from planning to commissioning


An ambitious project took shape in the Linz Chemical Park, where innovation and precision characterize daily industrial operations. LAT Nitrogen Linz GmbH, a leading producer of melamine, built a state-of-the-art wastewater treatment plant in collaboration with Linz-based Pörner Ingenieurgesellschaft mbH. This major EPCM project, which took three and a half years to complete, is a prime example of engineering excellence, logistical mastery and successful management of complex technical challenges.


In order to optimize the existing melamine production, the installation of a new, technologically advanced wastewater treatment plant was essential. LAT Nitrogen Linz GmbH, formerly Borealis Agrolinz Melamine GmbH, required an innovative solution that would meet the latest technological standards.


Pörner was awarded with the engineering, procurement and management of this project, with the task of developing a wastewater treatment plant that would comply with the highest environmental standards while meeting demanding process parameters.


The scope of the project has been formidable from the start: a total investment of around €42m, covering a wide range of engineering services, including authority engineering, extended basic engineering, detail engineering, project management, scheduling, procurement support with expediting, construction supervision, and commissioning support.


Dismantling and preparation: 1,500 tons of material moved


Before the new plant could take shape, extensive preparatory work was required: the dismantling of the decommissioned melamine plants 2 & 3. Over a nine-month period, 148 tons of insulation and piping, 1,200 tons of steel and aluminum, and an additional 160 tons of construction debris were professionally removed and disposed of.


The real challenge, however, was the construction of the new wastewater treatment plant for the process wastewater of the operational melamine plants 4 & 5. Pörner is well acquainted with the demanding process parameters of melamine plant 5 (175 bar pressure and temperatures


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Plant site before modernization.


exceeding 400°C), as it was planned by Pörner in 1998-1999.


Two superlatives on their way from Mumbai to Linz


One project highlight was the transport of the two hydrolyzers, the heart of the new wastewater treatment plant. Weighing 180 tons each and measuring 37 meters in length, these massive pressure vessels - manufactured in India - embarked on a global journey: from Mumbai by ship to Antwerp, and then down the Rhine, Main, and Danube rivers to Linz. Such an undertaking required not only logistical expertise, but also meticulous planning to ensure a smooth and efficient transportation process.


Installing these colossal units on the five-meter-high foundation strips on the plant premises presented an additional challenge. Due to space limitations, cranes could not be used to lift the heavy equipment. Instead, a special hydraulic lifting/sliding system was used to position the hydrolyzers with millimeter accuracy.


Circular economy and cutting-edge technology in focus


In the melamine plants, urea is used as the feedstock from which the final product, melamine, is purified and isolated by aqueous processing. The mother brine used in this process is largely recirculated. For quality reasons, it is necessary to discharge a minimum amount of mother brine. Two existing thermal wastewater treatment plants


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previously carried out the treatment of this „process wastewater“. In the course of the project, a new plant with the best available technology replaced these and a 1,000 m³ double wall tank was built to buffer the raw process wastewater.


The wastewater treatment plant consists of two pressure vessels (hydrolyzers) connected in series and run at an operating pressure of 45 bar and an operating temperature of over 230 degrees Celsius. These demanding parameters require the highest material quality and structural precision. As the wastewater flows through the two hydrolysers, the organic nitrogen compounds are hydrolyzed to ammonia and carbon dioxide by reaction with water. In addition to the hydrolyzers, this state-of-the-art hydrolysis plant includes an integrated system of heat exchangers and a stripper. The stripper removes ammonia from the wastewater, which is then condensed and recirculated into the process as an ammonium carbonate solution. The purified “process wastewater” is recooled via heat exchangers and, after controlling all legal limits (pH, temperature, turbidity, etc.), is discharged into the cooling water channel.


The numbers speak for themselves: 40 equipment units, 8,100 meters of piping, 3,600 flanges, 3,700 bends, 2,000 fittings, and 300 EI&C field devices were prefabricated, installed and tested. A


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