Ammonigy & Juwö Poroton: cracked ammonia fuel for brick manufacturing

In our November episode of Project Features, Jahn Faust (Project Engineer, Juwö Poroton) and Christian Hermle (Managing Director, Ammonigy) discussed their demonstration project in Germany for brick production using cracked ammonia fuel. The recording is available on our website, and you can also download the speaker presentations.

Ammonia to heat applications

Click to expand. Summary of various demonstrations of ammonia for industrial heat. From Kevin Rouwenhorst, November 2025 Project Features introduction.

Ammonia is a zero-carbon fuel that can be used for high temperature heat applications. Various use cases are emerging, with demonstrations to date including glass manufacturing (architectural glass and glass bottles), ceramics manufacturing (including brick manufacturing and tiles manufacturing), cement manufacturing, copper refining, and aluminium heating. Ammonia-rich fuel mixtures are also sometimes combusted for heat in the hydro treating section of refineries.

Ammonia/hydrogen fuel is just one possible solution for decarbonizing these applications, along with electrification by renewable power. The final choice will depend on a range of factors, including reliable availability of fuel molecules and/or renewable electrons, CAPEX and OPEX requirements, and added costs to the final product (and customer willingness to pay this premium).

Brick manufacturing at Juwö Poroton, and the potential role of ammonia fuel

Juwö Poroton is a German brick manufacturer, located in Wöllstein, close to Frankfurt. The company has 100 employees, and two production lines for bricks. One of the lines is focused on bricks for the Belgian and Dutch markets, and the other line is focused on the German market. The annual thermal energy use is around 65 GWh (equivalent to about 12,500 tons of ammonia fuel, on a lower heating value basis).

Click to expand. Juwö Poroton company overview.  From Jahn Faust & Christian Hermle, CO₂-free brick production (Nov 2025).

Brick manufacturing includes five main steps: (1) open pit mining of clay, (2) material preparation, (3) extrusion, (4) drying, and (5) firing. Clay represents around 90% of the brick, with the remaining 10% being additives. Material preparation includes material crushing with the roller mill, and subsequent storage for homogenizing the moisture content in the clay materials. The next step is extrusion using a die, which gives the brick their shape.

About 99% of the process heat is used in the last two process steps, namely drying and firing. The drying step will reduce the residual moisture (water) content below 1%. The firing step in the kiln will occur at fast heating rates, reaching 850°C. Too much moisture will cause cracks and the product quality will suffer. In the firing step, the materials are sintered, creating a ceramic phase in the product and changing the chemical composition of the clay. At 850°C, any additional materials for shaping (like paper) are burned out, leaving the desired pores. Thereafter, the bricks are cooled, the products are packaged, and the bricks can be sold.

Currently, Juwö Poroton uses gas as a fuel, which is readily available and currently the cheapest option. Various other options exist for decarbonizing the brick manufacturing, including electrification, hydrogen, and ammonia. Electrification can cause a high capital investment, electricity prices in Germany are generally high, full decarbonization of the grid is still required, and the current grid connection in Wöllstein is not sufficient at the moment. Given that the cracked ammonia fuel used in the demonstration was mostly hydrogen, this is another option. The hydrogen core network is under development in Germany, but there are no plans for a connection to Wöllstein at the moment, which would necessitate hydrogen transport by truck (estimated at 5 trucks per day). Ammonia is another option — when renewable ammonia is used. Existing infrastructure may be used for brick manufacturing, with some modifications. Ammonia can be sourced from relatively nearby, with BASF’s Ludwigshafen site at around 60 kilometres away, which already produces renewable ammonia. It is estimated that 2-3 trucks per day would be required for ammonia fuel transport. As far as we know yet, the ammonia case has the lowest capital expenditure and operational expenditure among the alternatives considered, although there is still a significant cost gap with gas.

Ammonigy: Ammonia Fuel Refinement for various applications

Click to expand. Ammonigy’s partial ammonia cracker system.  From Jahn Faust & Christian Hermle, CO₂-free brick production (Nov 2025).

Ammonigy was founded in 2020, and focuses on ammonia to heat and power applications. Ammonigy has developed an ammonia cracking solution known as the “Ammonia Fuel Refinement” system. In 2022, the system was first demonstrated via integration with a 50 kW engine onboard the modified speedboat GREEN AMY. This year, along with partners Heraeus Precious Metals and the Technical University of Darmstadt, the use of cracked ammonia fuel was again demonstrated in a 110 kW four-stroke MAN ES engine. Deutsche Bahn and Fortescue are also collaborating with Ammonigy to modify existing diesel engines to run on hydrogen & ammonia fuel.

Within the “CO₂-free brick production” project, Ammonigy teamed up with Juwö Poroton, the Fraunhofer Institute (IMM and ITWM), and industrial burner manufacturer Industrie-Brenner-Systeme (IBS) for the successful development and demonstration of a pilot brick kiln that runs on cracked ammonia fuel gas (approximately 90% hydrogen, 10% residual ammonia).

Operations

An ammonia cracker was introduced prior to a conventional 80 kW propane gas burner, with various operational conditions tested. The flame temperature was at least 1600°C, similar to gas flame temperatures in a conventional brick kiln. Partial cracking was used to optimize the combustion properties of the fuel. The ammonia cracker was able to follow fast load changes.

Click to expand. Emission measurements at the burner, showing the effect of increasing the air-fuel ratio.  From Jahn Faust & Christian Hermle, CO₂-free brick production (Nov 2025).

The nitrogen oxide emissions limits set by the Federal Emissions Control Ordinance (44th BlmSchV, at <100 ppm) can be met for stoichiometric air-fuel mixtures (𝛌=1), but higher nitrogen oxide emissions were reported at a surplus of air (𝛌>1). The second set of operating conditions is closer to what will be seen in an industrial kiln, and thus exhaust aftertreatment will be required to mitigate nitrogen oxide emissions, as well as potential ammonia slip. Applying exhaust aftertreatment (such as a scrubber or a selective catalytic reduction (SCR) step) to the “tunnel kiln” used in brick production is technically feasible, but will require significant work to engineer and optimize. Such SCR systems dedicated to elevated ammonia slip have already been developed for ammonia-fueled four-stroke engines.

Click to expand. Potential aftertreatment of cracker output to improve overall emissions performance.  From Jahn Faust & Christian Hermle, CO₂-free brick production (Nov 2025).

In the short-term, Ammonigy has been investigating the use of a downstream gas scrubber to “clean up” cracker output, reducing the level of ammonia slip and water that are fed to the burner in the cracked fuel mixture. Initial tests show that exhaust gas treatment is significantly simpler or may even eliminate the need for separate exhaust gas aftertreatment, and a follow-up project is being outlined.

The system in the “CO₂-free brick production” project was operated at 20 kW (with higher firing rates technically possible) and at 1000°C in a conventional oven, firing for 8 to 9 hours, comparable to industrial-scale firing for 12 to 13 hours. About 8 to 10 batches of bricks (7-8 in each batch) were used. The bricks passed Juwö’s in-house acceptance tests. The cracked ammonia-fired bricks were virtually “indistinguishable from bricks fired with natural gas”, albeit with a slight color change due to different burner operating conditions.

Challenges ahead, and is there a market?

As well as the technical and operational challenges discussed above, we discussed with our speakers whether there was a market for decarbonized bricks such as these in Europe. The short answer, said Jahn Faust, was a “disappointing no”. Currently, cracked ammonia fuel cannot not compete with the cost of energy from gas  (estimated at €0.04/kWh), and customers have indicated they were not willing to pay a premium for decarbonized bricks. These market conditions and cost gaps are certainly not locked in – but will likely have to change in order for a market to emerge.

On the regulatory side, it is worth remembering that, the last time Juwö Poroton made the transition to a new fuel (oil to gas), there was significant work involved. A move to ammonia fuel would be more work again, given the hazard profile and emissions requirements.