Compact microchannel ammonia crackers

Pochari Systems is designing, manufacturing and commercializing the world’s first highly compact ammonia cracker to produce hydrogen on demand from liquid ammonia for hydrogen internal combustion engine vehicles or fuel cells.

The cracker uses 4% wt Ruthenium and 20% wt Cesium promoted aluminum oxide supported catalysts in a microchannel configuration.

The cracker specifications are based on Engelbrecht and Chiuta 2018, Chiuta and Everson 2015 and 2016, Di Carlo and Vecchione 2014, and Hill and Murciano 2014.
The activation energy is as low as 49 kJ/mol of NH3 with high cesium promoter loadings on CNT support, which translates into only 5 KW of heat energy per kg of H2 reformed per hour, allowing for over 100% of the required energy for decomposition being provided by exhaust heat from the engine.
The amount of ruthenium and cesium needed is very minimal, only 1 gram 5 grams respectively is required to reform 1 kg of hydrogen per hour at the desired efficiency and power density.

Cesium is critical in the cracking process as it allowes high conversion of ammonia at lower exhaust temperatures, minimzing unburned ammonia emissions.

Cesium reserves are estimated to be 84,000 tons, with Ruthenium reserves 11,300 tons, since 5x more cesium is used than Ruthenium, the reserves allow for the production of billions of medium-sized car crackers.

Roughly half of the cost of the cracker is found in manufacturing, with the balance comprising raw materials.
Forming the microchannels from a solid metal block is performed by wire electrical discharge machining.

Washcoating and packing of the catalyst inside these tiny grooves completes the manufacturing process of a microreactor. Microreactor technology can be thought of as relatively simple compared to battery manufacturing as an example. The only complexities and difficulties arise from the very small dimensions
These small dimensions found in microreactors (as little as 0.15 mm x 0.25 mm) requires elaborate and costly machinery to fabricate, but nonetheless, the cost of the cracker will be approximately $1000-2000 per kg-hour of capacity at high production volumes, of which 50% represents material costs at current raw material market prices.
The ammonia cracker is located on the exhaust manifold for hydrogen combustion engines, utilizing engine exhaust heat supplying 100% of cracker energy needs, with hydrogen combustion providing the balance.
The volume of the ammonia cracker for 12 kg/hr, sufficient for the average fuel flow used by a class-8 semi-truck fully loaded at highway speed, takes up only 6 liters, and weighs less than 10 kg!
The cracker is configured in a modular fashion. The modules consist of a housing, each consisting of a stack of microchannel plates. The module is placed directly outside of each exhaust outlet on the cylinder head, allowing the very hot exhaust gas to pass directly into the microchannels before cooling down. This allows heating the catalyst bed to provide the necessary activation energy. Each module is connect to four rails, supplying both gaseous ammonia to the cracker, and passing reform gas to the purifier. The two smaller rails provide air and hydrogen to provide heat during startup.

Reactor type: Micro-channel

Catalyst: 4% Wt Ru, 20% Wt Cs promoted on CNT

Total catalyst mass per kg hour H2 reformed: 25 grams

Ru Catalyst required per Kg hour H2 reformed: 1 grams

Ce Catalyst promoter per Kg hour H2 reformed: 5 grams

Gravimetric density: 0.50 kg/kg H2-hr

Volumetric density: 0.5 L/kg H2-hr

Energy consumption: 5.5-6 kw/kg H2-hr

Percent of reforming energy from exhaust heat: 100%

Additional hydrogen consumed for dissociation: 0% of fuel flow

Ammonia hydrogen density: 103 kg/m3

Ammonia consumption: 6 kg liquid NH3/kg H2-hr

Startup time: 10 minutes

Cost per kg hr capacity: $2000

Ruthenium price: $8000/kg

Cesium price: $30,000/kg

Carbon nanotube price per kg: $10,000

7 thoughts on “Compact microchannel ammonia crackers

  1. Have you an ammonia cracker currently that’s suitable for use in a family sized car fitted with a fuel cell etc?And if so, what’s the price? If not, are you planning to build one? When? And any idea of price?

  2. Hi
    We require Ammonia cracker to produce pure and dry Nitrogen for pit type and In-line heated tube type annealing furnaces for annealing of drawn Nichrome wires. Will this ‘compact Microchannel Ammonia Cracker ‘ would work and viable for us. Please provide details and the cost for one unit of the same with technical explanations.

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