Technologies that do more with less

Technologies that do more with less

Striking the right balance between profitability, energy efficiency and reuse carbon dioxide can be challenging. Linde has teamed up with BASF to resolve this dilemma in the steam reforming business.

  • Linde developed the DRYREF™ technology in collaboration with BASF to make steam reforming more energy- and cost-efficient. 
  • DRYREF technology uses the recently developed BASF catalyst SYNSPIRE™ G1-110, which reduces the amount of steam required in the reforming process. 
  • It also enables plants to reduce their carbon footprint by putting "waste" carbon dioxide to good use. 
An innovative catalyst combined with clever process technology is revolutionizing synthesis gas production – a key process for many industries. The commercial maturity of DRYREF™, an optimized process for syngas plants, is paving the way for a lot more than just steam savings.

Synthesis gas (syngas) is an essential raw material for the chemicals industry. Its constituent gases hydrogen (H2) and carbon monoxide (CO) are used to synthesize important base chemicals like methanol, acetic acid or ethylene glycol, as well as to produce synthetic fuels such as diesel and gasoline. Syngas is usually produced by means of steam reforming, which typically requires huge volumes of steam. “The reaction of steam and natural gas produces H2 and CO in the presence of a catalyst. However, steam has to be added in excess to the reaction requirements and the surplus steam has a considerable impact on the energy balance of a steam reforming plant,” explains Thomas Bartesch, process engineer for hydrogen and syngas plants at Linde Engineering. “That is why we looked for ways to reduce the steam-to-carbon ratio, or in other words to use less steam to produce CO-containing syngas.” Acetic acid is one example of a product that requires a higher proportion of CO in syngas.

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New catalyst for improved steam reforming 

Reducing the steam input is easier said than done, however. It would result in the formation of carbon deposits on the surfaces of conventionally used catalysts and block the key reaction, i.e. the conversion of natural gas and steam into synthesis gas. To get around this problem and improve the steam reforming process overall, including its efficiency, the specialists at Linde Engineering joined forces with the catalyst experts at chemicals group BASF. The project also brought prestigious academic partners like the Karlsruhe Institute of Technology, the Technical University of Munich, the University of Leipzig and DECHEMA Forschungsinstitut on board.

“Thanks to BASF’s strong record in catalyst research and the outstanding screening expertise of BASF’s subsidiary hte®, we were able to develop an innovative catalyst specifically for this particular challenge,” explains Virginie Lanver, BASF project manager for the development of new process catalysts. Like the conventional catalysts used to date, it is based on nickel. “The difference is that we managed to optimize the crystal structure and the exact composition of the catalyst in such a way as to suppress the formation of soot on the surfaces due to the drier conditions thanks to a kind of self-healing process,” continues Lanver. “This allows the catalyst to remain active even when the steam-to-carbon ratio drops.”

Thanks to the upgraded catalyst, we were able to optimize the process design and improve energy efficiency while reducing operating costs.

Smaller investment – bigger savings 

“The upgraded catalyst is at the heart of our new steam reforming process,” adds Linde process engineer Bartesch. “This breakthrough development allowed us to optimize the process design and thus increase energy efficiency while reducing operating costs.” The result of these efforts is the DRYREF™ technology. The SYNSPIRE™ G1-110 catalyst developed by BASF was thoroughly tested, initially at lab and miniplant scale and later in Linde’s pilot reformer and at a commercial plant. In the lab, the new catalyst made it possible to reduce the steam-to-carbon molar ratio down to 0.9 – with the surface remaining free of carbon deposits. By way of comparison, the typical minimum value in conventional steam reforming lies in the 2.0 to 2.5 range.  

As well as requiring less steam, Linde’s DRYREF syngas plant offers further economic benefits. Plant components like the integrated CO2 removal unit or the CO2 recycling compressor can be considerably downscaled, which reduces the investment costs for new plants. In existing plants, process steam can be reduced to a certain extent and more steam can be exported, which translates into lower operating costs. Linde Engineering has calculated the cost saving for a new build syngas plant with an hourly capacity of 50,000 normal cubic meters at up to twelve million dollars in its first five years of operation. In this example, the engineers compared a conventional plant with a DRYREF plant.

Recycling carbon dioxide to save costs 

“The lower steam ratio simultaneously allowed us to produce syngas with a higher CO content – thus meeting customer-specific requirements in relation to the gas composition,” relates Bartesch. Energy efficiency is a further highlight of the DRYREF process, enabling operators to reduce CO2 emissions. In addition, surplus carbon dioxide can be recycled. “This gives us another pathway to improve the carbon balance. It is even possible to use CO2 from other processes for DRYREF,” Bartesch adds. When you factor in this CO2 import option, the cost benefits of DRYREF compared with conventional processes become even more compelling. With the above-mentioned example of a 50,000 normal cubic meter per hour syngas plant, this would mean an operating cost saving of up to twenty million dollars in the first five years of service – again when comparing a DRYREF plant with a conventional facility.

The DRYREF technology is tested at the Linde Pilot Reformer in Pullach, Germany.
The DRYREF™ technology is tested at the Linde Pilot Reformer in Pullach, Germany.

Leveraging synergies to drive innovation 

“Our cooperation with Linde Engineering is a perfect example of how two companies can team up to drive innovation forward,” maintains BASF expert Lanver. “We have set ambitious targets for the reduction of our own CO2 emissions as well as those of our customers. Linde is taking this issue just as seriously as we are, and has successfully integrated our recently developed SYNSPIRE catalyst into its DRYREF technology through its own process innovations.”  A major role was played here by the Linde Pilot Reformer, which allows the plant specialists at Linde’s Pullach site in Germany to test new process technologies under real-world conditions. The engineers went on to demonstrate commercial maturity of the DRYREF technology at an industrial-scale synthesis gas plant. “The lower investment and operating costs make this process highly attractive for new plants in particular,” claims Bartesch. “But we also develop tailored solutions in conjunction with existing customers, with revamps being just one example.” The objective is the same for every plant: do more with less.

Milestones from research to commercial maturity

  • Phase 1 (2010-2014): Catalyst screening

    Linde and BASF established the catalyst concept and process flow of the DRYREF™ plant within the framework of a government-funded project in collaboration with academic partners (Karlsruhe Institute of Technology, the Technical University of Munich, the University of Leipzig and DECHEMA Forschungsinstitut). BASF subsidiary hte® was responsible for extensive catalyst screening in a highly efficient, high-volume test facility. The result was the SYNSPIRE™ G1-110 catalyst.

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  • Phase 2 (2014-2016): Catalyst development and lab tests

    The BASF experts upscaled the production of the SYNSPIRE™ G1-110 catalyst from a few grams to a few hundred kilograms. Following extensive performance tests in the lab and at miniplants, Linde and BASF were able to confirm that the catalyst offers unique resistance to coking at a low steam-to-carbon ratio.

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  • Phase 3 (2016-2017): Pilot testing

    The Linde Pilot Reformer was installed at Linde’s Pullach site in Germany. It enabled the engineers to test the new process technologies under real-world conditions. With the help of complex measuring equipment, they were not only able to analyze the performance of the upscaled SYNSPIRE G1-110 catalyst pellets, but also test the optimized DRYREF process parameters in fine detail. This step helped to accelerate catalyst development from the lab to industry.

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  • Phase 4 (2017-2018): Commercial demonstration

    Linde demonstrated the commercial readiness of the DRYREF™ technology at an industrial-scale syngas plant with full product utilization.

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