Nitrogen+Syngas 382 Mar-Apr 2023
31 March 2023
Emissions-free syngas manufacturing
ELECTRIFIED STEAM METHANE REFORMING
Emissions-free syngas manufacturing
The world’s most common syngas production method remains steam methane reforming, a process which has a substantial CO2 footprint as the necessary reaction heat is supplied by combustion of hydrocarbons. Topsoe’s eREACT™ technology allows for the first-of-its-kind electrification of the traditional SMR process. The reaction heat for eREACT™ is instead generated directly by (renewable) electricity, thereby eliminating the flue gas altogether. Having gone through scale-up from bench scale to industrially relevant pilot scale the technology is now ready for industrial application.
As the world moves to decarbonise, chemical technology is required to evolve. Topsoe’s eREACT™ is the electrified evolution of the world’s most common syngas production method, steam methane reforming (SMR). Bridging existing syngas manufacturing with renewable electricity allows for an emission-free chemical plant, built on the existing principles of the syngas platform, allowing leverage of existing hydrocarbon infrastructure or integration with other carbon feedstocks such as biogenic carbon or captured CO2 , effectively allowing chemicals production on existing principles. Options for chemicals production utilising the eREACT™ technology is shown in Fig. 1, demonstrating the versatile range of products and feedstocks linked by eREACT™ . While traditional SMR typically generates needed heat through combustion of natural gas, which results in CO2 emissions, eREACT™ facilitates the same reaction without the associated environmental impact. The reaction heat for eREACT™ is generated directly by (renewable) electricity, thereby eliminating the flue gas altogether1 . With the cost of renewable electricity decreasing rapidly, this groundbreaking technology empowers even existing industrial complexes to electrify syngas production in a cost-effective manner.
Technology scale-up
The eREACT™ technology is the output of many years of development from Topsoe in transforming existing knowledge from SMR technology to an emission-free electrified counterpart. Having gone through in-house scale-up, the technology is now ready and is currently being demonstrated on an industrially relevant scale using an actual biogas feedstock (methane-rich gas produced by anaerobic digestion of biomass waste) for production of synthesis gas for green methanol. Based on several thousands of hours of operation, the eREACT™ technology has demonstrated conversion of biogas to syngas as an embodiment for syngas manufacturing. Key results and conclusions include:
- Demonstration of the reactor technology: All elements of the electrical reactor were demonstrated in the pilot plant operation.
- Operation at various conditions including feed gas composition, pressure, and temperature (up to 1,050°C): The reactor performs as predicted and expected according to thermodynamics.
- Test of upset situations including trips: Trips occurred both intentionally and caused by malfunction of the peripheral system not related to the electrical reactor. After all trips, the electrical reactor performance was easily brought back to the status before the trip.
- Test of transients: The power load was reduced from 100% to 50% and increased from 50% to 100% very rapidly. This demonstrates the excellent load following potential of the eREACT™ reactor technology. Rapid start-up was also demonstrated.
The technology enables high carbon utilisation, high energy efficiencies, and high stability. Still based on the thermodynamic principles known from fired steam methane reformers, eREACT™ technology demonstrates a larger operating window than conventional SMR technology, allowing for process intensification such as higher temperatures combined with flexible and direct control of the reactor for precise and faster operation response.
Process design
Syngas manufacturing by eREACT™ builds on all previous experience of syngas manufacturing. Consequently, when designing a process around the electrified solution, most of the processes resemble known practices from existing steam reforming plants. The front-end of the process is basically the same as traditional SMR type plants, where feedstock cleaning (sulphur removal) is needed as a first step followed by steam addition and pre-reforming. Downstream of eREACT™ , the process steps can be chosen freely according to the desired end product, similar to producing synthesis gas by SMR.
The eREACT™ technology offers a simplified solution for syngas manufacturing compared to conventional steam methane reforming, where the fired reformer is operated by balancing two chemical reactors against each other; on the one side, the combustion reactor, and on the other side, the catalytic reactor. In contrast, eREACT™ is an integrated system where heating takes place by direct electricity transfer into the catalyst. This translates into eREACT™ being very agile in operation, allowing fast start-up, fast capacity change, and precise temperature control, all because the plant control is reduced to a direct feedback control loop between syngas temperature and the power supply (PSU) power levels; where a PSU can change power levels on a millisecond scale.
The reduced complexity of eREACT™ translates into an equivalent reduction in the plot plan of the chemical site. Firstly, eREACT™ is a process-intensified reactor compared to SMR, markedly reducing the volume of the unit. Secondly, the utility site is also reduced in complexity.
Minimum requirements for an SMR layout are:
- fuel gas feed section
- a combustion air feed section (including blowers and preheaters)
- combustion chamber
- catalytic reactor(s)
- waste heat boiler
- flue gas waste heat section,
- and a flue gas stack.
In contrast, the eREACT™ solution only requires:
- catalytic reactor
- waste heat boiler
- power supply unit.
In greenfield opportunities, eREACT™ enables efficient feedstock utilisation where practically all carbon feedstock can be converted to an end product. Process layouts can be made completely emission-free, as no firing is needed. This gives an excellent match with carbon capture in, e.g., hydrogen production sites, where excess CO2 production can be captured from pressurised syngas, utilising existing efficient proven technologies for CO2 removal. For comparison, state-of-theart hydrogen production by SMR has a carbon intensity of approximately 9.2 kg CO2 / kg H2 (kg CO2 emitted per kg H2 produced) without CO2 capture and approximately 3.6 kg CO2 /kg H2 with process CO2 capture. eREACT™ enables the carbon intensity to be reduced to approximately 5.7 kg CO2 /kg H2 without CO2 capture (corresponding to process stoichiometry) and <0.1 kg CO2 /kg H2 with process CO2 capture; an excellent solution for blue hydrogen production from natural gas. In other words, natural gas use is reduced by 30-40% and CO2 emissions can be reduced by 99%+ for eREACT™ compared to SMR (Fig. 2). Electricity input is obviously needed, which is approximately 1.1 kWh/ Nm³ of hydrogen produced. Similar results are achieved when evaluating the production of methanol, ammonia, synthetic fuels, among others, with the eREACT™ technology. In addition, eREACT™ offers the opportunity to retrofit existing syngas installations by integration with existing reforming units for increased syngas manufacturing, but where the added capacity does not have an associated CO2 emission.
eREACT™ is the next evolution step of syngas manufacturing. It offers an agile solution for best-in-class performance for chemicals and fuels production with minimal to no carbon intensity, but also allows a platform for sustainable chemicals production when the sustainable carbon is used as feedstock. In a world where energy is a valuable resource not to be wasted, eREACT™ provides operators with the possibility to run their plants while nearly eliminating energy waste.
Conclusion
eREACT™ is a novel technology for syngas manufacturing. It is the world’s first electrified reforming technology. As it is constructed to have the hottest part centrally in the reactor, it allows for high temperature operation around 1,000°C or above, allowing for high methane conversion and potentially operating pressures exceeding 50 bar for novel process integrations. Experimental experience demonstrated that continuous operation can be done at >90% methane conversion (according to thermodynamics). This translates into increased feedstock utilisation compared with SMR. Better utilisation of feedstocks is indirectly an essential means towards more sustainable chemicals productions, and in the end, it translates into chemicals plants based around the eREACT™ technology that can come very close to operating at stoichiometric conditions. Ultimately, eREACT™ will allow classical steam-reforming-based process plants to be turned into blue or green chemicals plants with minimal to no carbon intensity. In addition, the technology allows for integration with (biogenic) CO2 and biogenic hydrocarbons for production of (green) sustainable chemicals.
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