The Engineering department of Techint E&C has been working for some time in several studies and developments related to energy transition for different clients. For the past few months, the team in Milan, Italy, has dedicated time and effort to compare different green ammonia technologies for the Italian energy company Enel, which is leading in the field of sustainability and renewable energies.  

The study is part of a framework contract that, along with several studies, involves the analysis of this new technology, a key for the energy transition and decarbonization of production activities.

"As a company, it is an exciting job because it allows us to go in-depth into green ammonia and the new technologies that the market requires with a primary client that is very attentive to the issues of the energy transition," says Mauro Paganelli, Head of Process and QHSE Deptartment of Techint E&C in Milan.

"We are doing high-level consultancy work to provide Enel with the necessary technical elements to develop its business plans in this field. We are not only supporting a primary client, but we are developing our competence in a technological field to prepare for what will probably be a blooming of its large-scale application," he adds.

A change agent

A chemical compound of nitrogen and hydrogen (NH3), ammonia is a colorless gas that is primarily used for making fertilizers. It is also used in industrial processes and for making cleaning products and disinfectants. Studies are underway for using ammonia as a carbon-free fuel and energy vector, given that the transportation of ammonia is more accessible than hydrogen.

"Normally around 80% of ammonia ends up in fertilizers, but it could also become significant as an energy vector based on hydrogen. This is important because renewable energies are extremely variable (solar energy is unavailable at night, and with wind energy, you must consider seasonality). We can produce hydrogen through electrolysis, but we need a way to store and transport it in large quantities. Although fertilizers are fundamental, we are studying and evaluating the production, transport, and reconversion of ammonia as in the port of arrival of ammonia as an energy (hydrogen) carrier," Paganelli says.

Paganelli warns that ammonia has problems, such as toxicity, corrosivity, and flammability, but he says these are manageable.

Ammonia has many advantages. It can be transported as a liquid at atmospheric pressure (even if at -33° C) or under slight pressure. Ammonia is a well-known product that has been known for centuries and industrialized and transported for decades. It is a good alternative that has an extremely high percentage of hydrogen.

How is it produced?

Ammonia is traditionally produced from the gaseous reaction of nitrogen and hydrogen. This reaction takes place very slowly at ambient conditions and requires a significant increase in pressure and temperature in the presence of a specific catalyst that facilitates the breakdown of nitrogen and hydrogen molecules until, finally, ammonia is formed. This is known as the Haber-Bosch process. The hydrogen in this process is usually obtained from methane reforming with steam, which leads to carbon dioxide emissions. These emissions come from furnace chimneys when natural gas is burned to create the heat for the reaction, and also because CO2 is a byproduct of reforming, which is separated from hydrogen and released into the atmosphere.

By comparison, green ammonia is a technology that takes part of the typical reactor section of ammonia production but obtains hydrogen from an electrolysis system powered by renewable energy, meaning that carbon dioxide is not emitted in the production cycle.