Magazine: Nitrogen+Syngas

A move towards smaller scale feedstocks such as renewable energy and waste and biomass gasification is leading to increased focus on improving the efficiency of small-scale, modular plants.

Reducing carbon footprint in the synthesis of chemicals is a new challenge, a necessary requirement in the pursuit of sustainable products designed to minimise environmental impacts during their whole lifecycle. So-called “green” technologies for ammonia, methanol and hydrogen are being developed to meet these challenges. Casale, Linde, thyssenkrupp Industrial Solutions, Toyo Engineering Corporation, Haldor Topsoe and Stamicarbon report on some of their latest developments.

A detailed rain and wastewater concept is an important part of a urea plant to meet current stringent environmental standards. Wastewater can originate from the process reaction or from outside the process equipment. In order to optimise the wastewater system of a urea plant, both the amount and type of contamination need to be known. With this knowledge, non-contaminated rainwater as well as process drains can be kept separate as much as possible to minimise the amount of wastewater to be treated, saving costs and energy. Wastewater treatment concepts from thyssenkrupp Industrial Solutions and Toyo Engineering Corporation are described.

Rapidly escalating natural gas prices forced plant closures across Europe during September. Worst affected was the UK, where a fire at a cross-Channel electricity cable and low output from wind energy has, combined with low domestic storage capacity led to a surge in demand for gas for power stations and wholesale gas prices reached a record 350 pence per therm (equivalent to $46/ MMBtu) in October. On September 15th, CF Industries announced that it was halting operations at both its Billingham and Ince fertilizer plans due to high gas prices. Although ammonia prices have also risen, they have not kept pace with gas price rises, and there is a limit to what farmers could be expected to pay. CF CEO Anthony Will said: “$900 is the gas cost in a tonne of ammonia and the last trade in the ammonia market that was done was $700 a tonne”. As these plants supply most of the UK’s carbon dioxide for food and drink manufacture, the government said it would provide “limited financial support” to keep the Billingham plant operational, and that plant re-started on September 21st. Meanwhile, BASF closed its Antwerp and Ludwigshafen plants in Belgium and Germany due to what the company called “extremely challenging” economics. Fertiberia ceased production at its Palos de la Frontera site in Spain, and Puertellano remained down for scheduled maintenance. Yara shut 40% of its European ammonia production in September, and OCI partially closed its Geleen plant in the Netherlands. Achema in Lithuania decided against restarting its ammonia plant following maintenance in August, and OPZ in Ukraine shut one ammonia line at Odessa, with Ostchem and DniproAzot likely to follow. Borealis in Austria also reduced production.

Borealis has announced the appointment of Rainer Höfling as CEO of its International Fertilizer & Melamine business, as of 1st October 2018. This business unit comprises approximately 2,000 employees. The dedicated management team under the lead of Rainer Höfling will provide higher agility and increased customer focus for the business. Borealis runs fertilizer production sites in Austria, France, the Netherlands and Belgium and melamine production in Austria and Germany.

Scanfeld™ is the world’s first remote sensing solution for fully automated early-warning gas leak detection for chemical plants. Using FTIR spectroscopy, Scanfeld™ identifies hundreds of different gases in real time from kilometres away. With just a few Scanfeld™ sensor units, large production sites, tank farms, or gas loading areas can be monitored reliably. Gas leaks are quickly detected, and the formation of dangerous gas clouds is monitored, measured, and visualised. René Braun of Grandperspective discusses how the system works and how it is being applied in industry.

Global nitrogen and methanol markets are currently in the grip of a crisis in feedstock prices. Mostly this is about Europe’s dependence on imported natural gas, but – particularly on the methanol side – it has also been exacerbated by high coal prices in China, where heavy rains have led to flooding in Shanxi province, the source of one third of China’s coal. These have followed similar floods in Henan in July, and come at a time when China is facing power rationing due to a lack of electricity supply. The world economy’s long-awaited bounce back from the covid pandemic has also led to a general global surge in energy demand, and consequently higher oil and gas prices.

In China, requirements for methanol to produce olefins, mainly propylene and ethylene, from coal, has driven much of the growth in global methanol demand over the past decade. However, a new wave of ethylene cracker investment may put a stop to new MTO plant building.

Every urea plant continuously fights again corrosion. The intermediate product ammonium carbamate is extremely corrosive under synthesis conditions. The applied materials of construction require oxygen to form a protective passive layer of chromium oxides. The ammonium carbamate solution will continuously dissolve the passive layer, therefore it is vital to continuously supply oxygen, typically in the form of air, to maintain the passive layer. During blocking-in conditions of the synthesis section it is not possible to add air and the oxygen present will be consumed as a result of the passive corrosion reactions, while at the same time the passive layer dissolves in the ammonium-carbamate solution. At a certain point, the oxygen content in the solution becomes too low to assure a passive layer. At that moment active corrosion will start with much higher corrosion rates than passive corrosion. The picture on the left side shows the passive layer (blue, brown, grey surface) and the picture on the right side shows active corrosion (a shiny silver surface). It is important to realise that once active corrosion starts it cannot be stopped, adding more oxygen at this stage, for example, will not work. Active corrosion will continue, leading to the risk that the protective layer will be severely damaged. The only way to solve this situation is to drain the synthesis section and re-passivate the surfaces.

Nitrogen-rich wastewaters remain a major issue for fertilizer and other industries. Saipem’s new electrochemical technology, SPELL, is an important step towards the overall objective of zero industrial pollution. A complete engineering review of the technology, its alignment with all international applicable standards, and optimisation has now been concluded and the technology is ready for deployment for the removal of ammonium nitrogen from industrial waters and wastewaters. Saipem discusses the key features of SPELL and reports on the first two industrial references.