Magazine: 372 Jul-Aug 2021

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.

At a time when green (or maybe blue) ammonia is being looked to as a way of reducing carbon emissions, substituting for hydrocarbons in a variety of potential uses, a conference held at the start of June was a reminder that nitrogen, its neighbour on the Periodic Table, is by no means off the hook on the environmental front. The Eighth Global Nitrogen Conference – held over from last year because of Covid-19, and this year held virtually, as most events are for the time being – was the latest in a series of tri-annual meetings convened by the International Nitrogen Initiative (INI), with support from the UN Economic Commission for Europe (UNECE) and the German Ministry of the Environment. The INI grew out of the 1979 UNECE Convention on Long-range Transboundary Air Pollution and 1999 Gothenburg Protocol, and is concerned specifically with ‘reactive nitrogen’ (i.e. nitrogen not tightly bound to itself in a triple bond, which makes up 78% of the air around us).

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.