Section: CRUNS Market & Features

Plans to decarbonise power production and shipping are leading to increasing interest in using ammonia as a fuel, but technical and economic barriers still remain to be overcome.

The internals of ammonia synthesis converters are generally made of austenitic stainless steel to withstand the harsh operating conditions (high temperature, high pressure and synthesis gas containing hydrogen and ammonia). Since nitriding is the most critical material degradation for the converter internals, Casale has set up a large nitriding analysis campaign. In the last decade, samples of materials operated under different pressures and temperatures and for different time spans have been tested and analysed. The data obtained has been used to increase nitriding knowledge and to establish a correlation to predict nitriding rate to allow the most suitable material and relevant thickness to be selected. L. Redaelli and G. Deodato of Casale report on how this correlation was established and provide valuable insight on this phenomenon and how to predict and control it.

To comply with stricter stack emission obligations, industries are required to recover more heat from flue gas and to clean it before it can be discharged into the atmosphere. J. Kitzhofer of APEX Group discusses the challenges and limitations of the majority of current heat recovery systems and reports on a new family of acid resistant tubular and plate-type heat exchangers developed by APEX Group that overcomes these problems. The new heat exchangers are resistant to dew point corrosion. The heat transfer elements are constructed from an acid resistant polymer composite with high thermal conductivity, allowing the design of new trouble-free heat recovery systems and the upgrade of existing systems to meet heat recovery and stack emission targets.

Metal dusting corrosion damage on steam reformers is no longer a major issue in modern methane steam reformer units. Nevertheless, failures related to metal dusting corrosion attack still take place in some specific designs and configurations that are more prone to experience this damage. Poor maintenance or deterioration of insulation components on transition areas might expose metallic surfaces to metal dusting attack. In this article, Dr P. Cardín and P. Imízcoz of Schmidt+Clemens Group describe different case studies, where the end users benefited from the experience of a collaboration to address potential risks and improve plant reliability against metal dusting corrosion damage.

M. Østberg and M. Rautenbach of Haldor Topsoe describe ReShift ™ technology, a new high temperature CO 2 reforming process, where preheated CO 2 is added directly downstream of a main reformer and then equilibrated in an adiabatic reactor. This new technology makes use of the high temperature of the reformer effluent to circumvent carbon formation, while at the same time maintaining an overall minimum steam to hydrocarbon carbon ratio, depending on process specific conditions. An increase in the amount of CO 2 added to the process will result in an increased fraction of CO in the produced synthesis gas. Synthesis gas with H 2 /CO ratios in the range 0.5-3 can be produced. These CO-rich gases are typically utilised in the production of functional chemicals and synthetic fuels.

February saw ammonia prices jump due to a series of plant outages, including EBIC in Egypt, and several plants in North America, including two on Trinidad; the 760,000 t/a Nutrien 4 plant and 500,000 t/a Tringen 2 plant, both due to gas shortages, as well as Yara and BASF’s 750,000 t/a unit at Freeport, Texas.

The ammonia industry has always dealt with fluctuations in supply and demand as well as volatile feedstock and energy costs. The unexpected global pandemic that started in 2020 has injected a higher degree of uncertainty for ammonia manufacturers’ operating costs and product demand for fertilizer. W. Poe of AVEVA discusses how advanced process control systems can help ammonia producers turn economic uncertainty into a competitive advantage.

Nitrogen+Syngas’s annual listing of new ammonia, urea, nitric acid and ammonium nitrate plants.

In August 2020 the tragic explosion of ammonium nitrate fertilizer in the port of Beirut caused many fatalities and injuries. This was a wake-up call for the entire industry to review the design of plants and storage facilities, as well as the procedures for plant operation and the handling of products. The key factor for safe new installations is the process design: the right choice of unit operations, operating temperatures and pressures, the control of process variables and the design of key items of equipment. A modern ammonium nitrate (AN) plant design not only mitigates the environmental impact, but also reduces investment costs and contributes to the key factors mentioned. M. Pieper and P. Kamermann of thyssenkrupp Industrial Solutions discuss how, by using the right design, safety in ammonium nitrate plants can be easily achieved, while maintaining outstanding product quality.

Market Insight courtesy of Argus Media