R. V. Schneider, Chiyoda International Corp., Houston, Texas; and D. KUROSAKI, Chiyoda Corp., Yokohama, Japan
As developed nations press on towards a goal of net-zero carbon emissions by 2050, it has become a forgone conclusion that hydrogen (H2) will play a key role in the attainment of that goal. Often, population centers that need the volumes of H2 required to meet the forecasted needs of public and private transportation, material movement and power generation are often remote from the source of the produced H2; therefore, the dilemma of how to move large quantities of H2 from Point A to Point B must be addressed.
The authors’ company has developed a novel technologya for the transport of large volumes of H2. This technology is based on the use of a liquid organic H2 carrier (LOHC) and utilizes both an “off-the-shelf” hydrogenation catalyst as well as a proprietary and now-proven dehydrogenation catalyst. This process was piloted at the authors’ company’s Technology Development Center in Yokohama, Japan before being applied to a commercial-scale demonstration project in 2020, where it was successfully proven in moving hundreds of tonnes of produced H2 from Darussalam, Brunei (FIG. 1) to the port of Tokyo, Japan. This article will discuss the specifics of this demonstration project and illustrate how it provides a steppingstone for the next major commercial application.
Technology introduction. The authors’ company’s proprietary H2 transport and storage processa is intended for both H2 storage and the long-distance transportation of large volumes of H2. It has been developed over the course of many years of company research, previously published in the 2021 article “Advances in chemical carriers for hydrogen” in Hydrocarbon Processing and H2Tech. In the processa, H2 is chemically bound to the aromatic toluene (commonly found in many refineries) and therefore converted to methyl-cyclohexane (MCH), with each mole of toluene taking up three moles of H2 per the reaction shown in FIG. 2.
Once the MCH has been transported by any of several various means to the desired destination, it is converted back to H2 and toluene as depicted in the dehydrogenation reaction in FIG. 2. Recovered H2 may be further processed for enhanced purity or may be used “as-is”—depending upon the specifics of the application at hand—while the toluene is transported back to the site of H2 production for further processing into MCH (TABLE 1).
As such, MCH may be considered a circular carrier. The H2 purity for the company’s H2 transport and storage processa is > 99.8% and losses of toluene are considerably < 1%.
Simplified process flowsheet details for both hydrogenation and dehydrogenation sites have been provided in the previously published article. FIG. 3, however, shows the intended application of the H2 transport and storage processa as a large volume transport mechanism for moving large quantities of H2 over long distances: in this case, via an ocean-going chemical carrier.
The H2 transport and storage technologya and the proprietary dehydrogenation catalystb was demonstrated as the LOHC-MCH H2 supply chain concept in the pilot facility from 2013–2014 at the Yokohama Development Center (FIG. 4). In the pilot facility, which had a continuous capacity of 50 Nm3/hr, both the hydrogenation and dehydrogenation process were tested for operability, conversion and reliability. The catalyst test program was initiated by several years of bench testing before a suitable candidate for piloting was available. The catalyst test program was begun in 2002, and it was not until 2010 that a robust and ready-for-piloting catalyst became ready for the next step. The novel catalystb intended for the initial pilot tests was chosen on the basis of observed activity, selectivity and long-term stability.
More than 10,000 hr of test time were devoted to this initiative and once technical success was declared, it was deemed a successful campaign that could be concluded.
Following this successful pilot plant stage, the road was now paved for the next obvious step: a commercial demonstration.
The first supply chain commercial demonstration. The first demonstration of a H2 transport and storage processa-based supply chain was envisioned by early 2015, and by 2017 engineering of this concept was well underway. With several partners (Mitsubishi, Mitsui and Nippon Yusen), the authors’ company established the Advanced Hydrogen Energy Chain Association for Technology Development (AHEAD)—it was within this consortium that the decision was made to supply H2 by reforming the natural gas from an existing liquefied natural gas (LNG)-producing site in Brunei to the TOA oil refinery located in Kawasaki City, Japan (FIG. 5).
Additional support for this first-of-a-kind project was provided by Japan’s organization for New Energy and Technology Development (NEDO). Construction of the hydrogenation plant in Brunei was underway by early 2018 and was completed by the latter part of 2019. To optimize both construction costs and timing, and in consideration of local conditions at the Brunei site, a modular approach was adopted. This is further illustrated in FIGS. 6 and 7.
The construction of the hydrogenation facility at the Brunei site went smoothly and without material issues. Staying ahead of schedule was possible thanks to the use of modular construction, implementation of good project management principles and excellent cooperation from the Brunei government.
It was always intended that for this first commercial demonstration, the shipment of produced MCH out of Brunei would be by ISO-containers loaded onto ocean-going carriers. These containers were made out of steel and had a capacity of approximately 16 tonnes each [21,000 liters (l)]. Five ISO containers per week were transported from Brunei to Japan—a total of 111 MCH ISO Tank containers were received at Kawasaki City.
The H2 transport and storage process technologya comprises shipping MCH from one location to another and recovering the H2 from MCH at the site where the H2 is to be used. As such, a dehydrogenation facility was also required, and this unit was built at the port of Tokyo in Kawasaki City (FIG. 8). Construction on the 300-Nm3/hr (27-kg/hr) dehydrogenation plant was begun in October 2018 and completed in December 2019. The dehydrogenation plant (shown in FIGS. 9, 10 and 11) is described briefly here:
The raw MCH is heated and evaporated in the heat exchanger, and then fed into the dehydrogenation reactor. In the dehydrogenation reactor, the H2 and toluene produced are cooled, and only the toluene is condensed by the cooler and separated in the gas-liquid separator.
After going through the processes of boosting and cooling, the H2 becomes a product supplied to the end users. The condensed toluene after cooling is sent to the toluene tank along with the separated toluene from the gas-liquid separator.
The MCH was delivered from Brunei and then broken down catalytically into toluene and H2 via dehydrogenation at the newly constructed facility.
The red arrow in FIG. 12 shows the reaction area—the catalystb is contained within tubes: the reactor tube diameter and tube length are the same as would be used in much larger scale plants. The proprietary dehydrogenation catalystb performed as expected in plant operation and allowed for a continuous supply of H2 for export.
H2 taken from the Kawasaki City plant was fed via pipeline as a co-firing fuel to an existing gas turbine (GT) located within the TOA refinery. The H2 was supplied continuously and stably to the GT for nearly a year with the capacity of the dehydrogenation unit fluctuating between 40% and 100% without any material obstacles or failures. Heat for the endothermic dehydrogenation reaction was furnished by a hot oil system that was heated by a cylindrical-type fired heater. Toluene recovered from the dehydrogenation facility was subsequently returned to Brunei for further conversion to MCH.
The Brunei to Kawasaki City demonstration project was then operated from early 2020 until December of that year, at which time the effort was declared a technical success and transport operations via ISO containers were ceased. Within the demonstration period, 102 tonnes of H2 had been transported via the authors’ company’s H2 transport and storage technologya successfully to the Port of Tokyo and were subsequently consumed as a co-firing fuel within the TOA refinery site.
Further demonstrations as a part of the AHEAD project. From 2021–2022, the authors’ company provided thousands of tonnes of MCH within schedule and of the required quality from the AHEAD Brunei hydrogenation plant to the ENEOS refinery in Japan, which was supported by the Consortium for Resilient Oil Supply System (CROS). These shipments were by bulk ocean-going chemical carriers (like the one shown in FIG. 14) at this point rather than in ISO containers.
The AHEAD project has achieved a global-first milestone of transporting bulk quantities of H2—in the form of MCH—and this achievement demonstrates the viable long-term storage and transportation of H2 in the form of MCH by tanker on a global scale. Numerous studies have shown that other than via pipeline, ocean transport of H2 via the authors’ company’s MCH is the most economical and reliable means of transport for large quantities of H2 over long distances (e.g., Brunei to Japan, South America to Europe, Canada to Europe or Japan).
The broader use case of the MCH technology is shown in FIG. 15.
To better support domestic distribution, the authors’ company has developed and tested a compact-type dehydrogenation facility (downsized unit and with automatic operation), funded by NEDO in 2017. These efforts are required to keep developing smaller scale MCH-related operations to fit the needs of localized H2 refueling stations. This concept is shown in FIG. 16.
In this instance, H2 recovered from the compact dehydrogenation plant is necessarily purified to fuel cell use specifications and then compressed and stored locally for later dispensing. Generally speaking, when a fuel cell is the intended use, pressure swing absorption (PSA) purification will be required.
Between 2022 and 2023, the modular unit (FIG. 17) was engineered and fabricated in Japan. This compact dehydrogenation unit that will convert stored MCH into recovered H2 and toluene has now been installed at the Singapore site in Pasir Panjang terminal (FIG. 18).
The capacity of this unit is nominally 30 Nm3/hr [2.7 kilograms per hour (kg/hr)] after PSA purification and will produce ISO grade D H2 which is the required fuel cell specification. Operations have commenced within 2024 and it is intended that the test run will last approximately one year. Primary uses for the H2 produced from this semi-commercial test unit are a port facility heavy-duty FC vehicle (prime mover), like the one shown in FIG. 19.
Large-scale H2 hub for the future. FIG. 20 illustrates how the authors’ company’s H2 transport and storage technologya can integrate with other current options to further establish the desired eventuality of a large-scale green energy hub.
With green energy produced by various means (i.e., wind, solar, hydroelectric, nuclear), surplus power not required by grid demand at any given time can be stored ostensibly in batteries. However, given the current state of the technology, this option only makes sense for relatively short-term storage measured in hours. When the storage term increases from hours to days, it is reasonable to consider using surplus power to produce electrolytic H2, which may then be stored in gaseous form, for eventual use as a fuel for electric power generation.
But when the storage requirement drifts from days to weeks or even months, liquid storage using the authors’ company’s MCH makes imminent sense. Produced H2 converted by the H2 technologya to MCH may be stored locally or shipped to some remote storage facility. Thus, a commercially proven means is now available for domestic or export energy storage with no need for compression, cryogenic liquefaction or extensive use of batteries.
Takeaways. The authors’ company’s transport and storage technologya is a proven and reliable means for moving or storing exceptionally large volumes of H2. With this technology, atmospheric liquid may conveniently be transported internationally (if desired) by large chemical carriers, thus utilizing much existing infrastructure. Alternatively, this technology may be applied in local distribution hubs for the fueling of material movement equipment, delivery trucks and/or fuel cell electric vehicles (FCEVs) in most any form. The process scheme uses all proven types of equipment and the catalystb is likewise proven and commercially tested. This technology and know-how is available today for application to H2 transport or storage problems, no matter how small or how large. HP
NOTES
SPERA H2™
SPERA dehydrogenation catalyst
Robert V. Schneider, III is Senior Advisor to Chiyoda International Corp. in Houston, Texas. He was previously Senior Vice President and Director of Engineering and Licensing for Scientific Design Co. Inc. He has more than 40 yr of chemical process industry experience and a background in various process technologies including methanol, ammonia and ethylene oxide, industrial catalysis, sales and marketing, technology licensing and senior company management. Mr. Schneider previously held positions with Kvaerner Process (DAVY), the M.W Kellogg Co., United Catalysts/Sud-Chemie (now Clariant) and DuPont. He holds a BS degree in chemical engineering from the University of Louisville, Kentucky and an MBA degree from the University of South Florida. Mr. Schneider is a registered Professional Engineer in Texas, Florida and Kentucky.
Daisuke Kurosaki is the Group Leader for Hydrogen Supply Chain Development for Chiyoda Corp. in Yokohama, Japan. He has worked in a business development role in the H2 supply chain business since 2014; his assignment has included promotion of Chiyoda H2 transport technology business (SPERA), as well as responsibilities for the world’s first global H2 supply chain demonstration project between Brunei and Japan. Prior to joining the H2 business team, he led energy conservation studies for petrochemical complexes in Southeast Asia and the Middle East. He was involved in fuel cell cogeneration system development and wind farm project development before joining Chiyoda, and has 20 yr of experience in both technical and business development roles in H2 and related energy fields. Mr. Kurosaki holds BS and MS degrees in civil engineering from the University of Tokyo in Japan. As a part of his graduate studies, Mr. Kurosaki also studied at the University of California at Berkeley.