Development of a plasma-chemical plant for producing “pure” hydrogen
The goal of our project is to create a pilot plant for the production of hydrogen of at least 95%wt and capacity of 14 kg/h of hydrogen.
As a result of the project, an experimental installation for plasma pyrolysis of methane will be created and experiments will be carried out to demonstrate the possibility of implementing the technological process.
The method is based on the thermal destruction of methane molecules by the thermal energy of an AC electric arc. The produced hydrogen and carbon black are separated at various stages in the process. For stable operation of the plasma torch an additional gas is used (inert gas). After purification, inert gas is returned to the chemical process.
Raw materials (methane and inert gas) are fed from cylinders (11) to a high-voltage AC plasma torch (1). The flow rates of raw material are measured by mass flow controllers. AC electric arcs are ignited by high voltage obtained in the power supply (50 Hz, voltage is up to 10 kV). a Mixture of methane and inert gas is heated to a high temperature (mass-average temperature up ti 3000 K) by an electric arc.
As a result, the following chemical processes take place in the high-temperature zone: the detachment of hydrogen atoms from the methane molecule, the formation of C2 species. As it cools, most of the C2 species convert to acetylene, hydrogen, and carbon black. Plasma-chemical reactor is used (2) to reduce the concentration of acetylene in the product gas. In the plasma-chemical reactor, the temperature of the reaction mixture is reduced to 1200°C. When the residence time of the gases in the reactor is more than 2 seconds, most of the acetylene decomposes. This produces hydrogen, carbon black and a small amount of methane.
In a high-temperature heat exchanger (3), the reaction mixture is cooled. Since the concentration of dust (carbon black) in the gas is high, this can prevent the efficient cooling of the gas stream. Therefore, the refrigerator is equipped with a self-cleaning device.
The gas stream cooled to 200°C is fed into a bag filter (4), in which the gas mixture is purified from carbon black. When the hydraulic resistance of the filter rises, the filter clearing is automatically triggered. Backflushing is carried out from a gasholder containing a purified mixture of hydrogen and inert gas.
Raw materials may contain small amounts of sulfur, which can inactivate the PSA sorbent. Therefore, the next stage of cleaning is the adsorber (5) filled with a selective sorbent (zinc oxide or the like).
The product gas cleaned from acid gases is directed through the receiver (16) for separation to the PSA unit (7). Inlet pressure and mass flow rate are provided by the compressor (6). This produces purified hydrogen with a concentration of at least 95% vol. and a mixture of inert gas and methane. The flow rate and composition of the produced hydrogen is determined by suitable sensors and mass flow controller (15).
A mixture of inert gasn and methane with the help of a compressor (9) through a gasholder (10) is fed into the plasma torch together with a fresh portion of pure inert gas and methane. For the correct operation of the plasma torch and cooling systems a hydraulic and gas supply system is used (12).
The produced hydrogen and other process combustible gases are fed into the combustion chamber (8). The combustion air is supplied by a fan (14).
- Plasma torch with power supply system
- Plasma-chemical reactor
- Heat exchanger
- Bag filter
- Acid gas adsorber
- PSA for hydrogen separation
- Combustion chamber
- Gas supply facility
- System of hydraulic and gas supply and plasma torch control
- Cooling system
- Measurement of hydrogen flow rate and quantified analysis
- Plasma torch power supply
- Diagnostic chamber
- Control panel
The main part of the experimental facility equipment will be manufactured taking into account the possibility of transportation by land, air and sea transport and will be made in the dimensions of standard sea containers. Equipment that must be protected from the effects of precipitation, wind, rain or snow will be placed in containers or made in an all-weather design.
Material balance for processing 1 kg of methane. Accepted losses 1%. Atmosphere pressure.
- Process efficiency: 80%
- Methane (CH 4 ) 1 kg
- Inert gas 2 kg
- Methane (CH 4 ) 0,0099 kg
- Hydrogen (H) 0,2475 kg
- Carbon black (С) 0,7425 kg
Energy consumption of main equipment:
- 1) Plasma torch 200 kW
- 2) System of hydraulic and gas
supply and plasma torch control 6,85 kW
- 3) PSA unit 64 kW
- 4) Compressor 20 kW
Total energy consumption of main equipment – 290,5 kW.
Energy consumption of auxiliary equipment is not known so it was taken equal to 10% of the energy consumption of the main equipment.
Total energy consumption is 320 kW.
- for 1 kg of methane – 5,65 kW∙h
- for 1 kg of hydrogen – 22,85 kW∙h
The indicated energy consumption does not include the possible recovery of thermal and mechanical energy. When recuperating the energy of gas expansion in the PSA (pressure swing adsorption) the energy consumption will amount to 19,9 kW∙h/kg of hydrogen.
In addition, it is possible to recover up to 60 kW of thermal energy from the cooling system. In a low-capacity facility the use of heat recovery is impractical due to high capital costs. On an industrial scale, taking into account the recovery of thermal energy the energy consumption will be 15,6 kW∙h/kg of hydrogen.
Storage and transportation of hydrogen in any form (gaseous, liquefied, etc.) is a rather complicated process and requires many new technical and technological solutions. Therefore, in the near future hydrogen will most likely not be stored and transported in large volumes (such as oil, gasoline, gas, etc.). Hydrogen will be produced in exactly the same volumes as consumed and as close as possible to the place of consumption.
For large consumers, in the future, hydrogen will be produced mainly at large electrolysis plants or by means of modified SMR technology (with CO2 capture). For small- and medium-sized consumers, hydrogen will either be transported or it could be produced locally from natural gas using the plasma chemical technology we have been developing.
Natural gas logistics in the EU is already well developed (pipelines, transport, storage, filling stations, etc.), which greatly facilitates the transition to hydrogen. There is also no need to build all the accompanying infrastructure.
The fastest transition to hydrogen will presumably be in the transportation, since there are already a large number of ready-made technical solutions for hydrogen — cars, buses, infrastructure, filling stations, solutions for local production of hydrogen, etc. All these technologies are developing very quickly. Large automakers plan to completely stop production of trucks and buses with internal combustion engines by 2040. Car manufacturers are going to do this even faster, as soon as by 2025.
The solution we have been developing is, in fact, a ready-made mini plant. The technology can be scaled up based on the needs of various consumers, including wholesale fuel depots and filling stations for vehicles. Currently we have been developing the concept of modular solutions of various productivities.
In the future, we will be able to install our production modules right next to a filling station. There is no need to compete with existing filling station networks. Our solution for the production of hydrogen is an integral part of the value chain, and due to the low costs of hydrogen production (approximately 3 euro/kg) + the already existing infrastructure of natural gas, this solution is much more convenient and profitable compared to any other hydrogen production technologies, especially in comparison with electrolysis.
Mobile solutions for filling stations (CNG tank + hydrogen production module on one semitrailer) also look very promising.
The next stage of development envisions designing industrial plants of significantly higher productivity for larger consumers, such as large industrial enterprises, heat and power plants, etc. This requires additional elaboration of the concept and will be implemented in the next stages of the project.
The technological solution we have been developing will also make it possible to produce hydrogen from biomethane, which production is also actively developing. Under today’s standards, this will make the entire process of hydrogen production 100% “green” according to EU criteria.
No CO2 emissions! Compared with other mass methods of hydrogen production, which have a negative impact on the climate and the environment. The possibility of producing hydrogen also from bio-methane in the future will make the entire production process 100% «green»
Hydrogen is a complex fuel and requires specialized logistics. Our plants will allow the production of hydrogen for the end user directly at the point of its consumption.
The technology we are developing will be the cheapest way to produce «pure» hydrogen! The associated «clean» production of carbon black also has great prospects and reduces the cost of the entire process.
The technology we are developing has no competitors on an industrial scale today. The developed analogues will be released to the masses only after a decade.
The main part of the equipment of the technological unit will be manufactured taking into account the possibility of transportation by land, air and sea transport, which will allow the process of hydrogen production to be launched quickly, wherever it is needed.