Raven SR ($22M to on site convert organic waste, solid waste, or biogas to hydrogen and carbon-neutral fuels)

Raven SR, an American cleantech company founded in 2018, develops a unique steam/CO₂ reforming technology,  which transforms solid waste, organic waste, and methane into high-quality, clean hydrogen and Fischer-Tropsch synthetic fuels.

Challenge: waste gasification

We need to turn the carbonaceous trash into useful hydrogen-rich syngas. The hydrogen-rich syngas can be used to make hydrogen (H₂) fuel. Through the Fischer-Tropsch process,  the hydrogen-rich syngas can be reformed to renewable fuels.

Gasification is a technology that can turn any carbon-based raw material into syngas. Gasification occurs in a gasifier, which is a high-temperature and high-pressure vessel. In a gasifier, air and steam are directly contacted with the carbonaceous raw materials, triggering a series of chemical reactions that produce syngas.

Problems with gasification include poor conversion and the release of air pollutants. Complex organic compounds and the formation of soot and dioxin cannot be destroyed by the gasifier’s temperature, even if some of the feedstock is burned with oxygen or air to raise the temperature. Moreover, burning some of the feedstock creates CO₂, which dilutes the H₂ in the syngas. This combustion is fueled by adding air, which further dilutes the H₂ with nitrogen. Therefore, gasification has had many failed attempts, bad economics, and harsh criticism around the world as a “incinerator in disguise”.

Raven SR Technology

Raven develops a steam/CO₂ reforming technology that uses electrical heating to achieve exceedingly high temperatures in the reactor, thereby eliminating the need for combustion or oxygen-blown combustion. Through reforming chemistry, the high-temperature reactor can nearly completely convert hydrocarbon, CO₂, and steam to hydrogen-rich syngas with little CO₂ or N₂ diluent.

Raven hydrogen

Raven has designed various high-temperature reactors with electrical heating for producing hydrogen-rich syngas.

Figure 1 depicts a cylindrical reactor.

Figure 1: A cylindrical steam reformer reactor.
Figure 1: Raven SR cylindrical steam/CO₂ reformer reactor (ref. US20200048085A1).

The cylindrical reactor has a gasket-sealed flange lid on top, a vessel made of fiberglass to prevent a burning hazard, and a bottom plate with insulation foam.

There are several concentric tubes at the bottom of the reactor that are used to feed the reactor and remove the hot syngas. The hot syngas heats up the feedstock by transferring heat to it. After cooling down, the syngas is sent to pipes further downstream.

The reactor vessel’s annulus is mounted and welded to the bottom plate. On both sides of the annulus, square wire trips improve heat transfer.

The heating elements are mounted in the top flange. They are inserted downward from the top lid into two flow zones: one has upward flow in the outer annulus, and then the flow changes to downward flow in the middle of the annulus. The flow leaves the reactor at the bottom.

There are 16 heating elements in the outer annular flow region and 12 heating elements in the inner annular flow region. There are busbars on top of the reactor that power the heating elements. The total power for all 28 elements is 140 kW. Seven thermocouples are positioned near the heating elements to determine the temperature distribution.

During operation, feed gas enters the reactor through the outer of concentric tubes at the reactor’s base. The feed gas is preheated by the produced syngas which exits through the inner concentric tube. The preheated fed gas passes through a mesh, which generates turbulence to enhance heat transfer. The feed gas flows to the top in the outer annulus of the reactor vessel. It is further heated by the electrical heating elements. The hot gas then goes down to the center in the middle of the annulus and is heated by the electrical heating elements. The produced hydrogen-rich syngas exits through the center of the concentric tube at the bottom of the reactor.

Figure 2 depicts a reactor with a heat exchanger using a reradiating solid body at the bottom.

Figure 2: A steam/carbon dioxide reformer with solid body.
Figure 2: Raven SR steam/CO₂ reactor with solid body (ref. US20200048085A1).

The feed gas enters the bottom of this reactor through a pipe with a tangential entrance, which generates a swirling flow to enhance heat transfer on the fins. The feed gas is preheated by the fins’ heat transfer.

The feed gas flows to the top in the outer annulus of the reactor vessel. It is further heated by the electrical heating elements. The hot gas then goes down to the center in the middle of the annulus and is heated by the electrical heating elements.

The hot produced syngas passes over a reradiating body at the reactor base. Heat from the syngas is transferred to the radiating body. The radiating body has a glowing yellow-orange hot surface that radiates and conducts heat onto the surface of the fins, which preheat the feed gas. Thereby, the syngas gas is cooled by the reradiating body and leaves the reactor base via a pipe.

Figure 3 depicts a reactor with a bottom design for feeding gas to the reactor and extracting the syngas product.

Figure 3: A alternative type of steam/carbon dioxide reformer.
Figure 3: An alternative type of Raven SR steam/CO₂ reformer (ref. US20200048085A1).

The feed gas enters the reactor through a flange. The feed gas flows through the inner of concentric tubes, strikes the baffle, and has a uniform flow distribution in the bottom plenum box.

The feed gas passes through a screen and flows to the top in the outer annulus of the reactor vessel. It is further heated by the electrical heating elements. The hot gas then goes down to the center in the middle of the annulus and is heated by the electrical heating elements. The produced hydrogen-rich syngas exits through the outer of the concentric tube at the bottom of the reactor. The hot syngas transfers heat to the feed gas and preheats it.

Figure 4 depicts another reactor.

Figure 4: A alternative type of steam/carbon dioxide reformer.
Figure 4: An alternative type of Raven SR steam/CO2 reformer (ref. US20200048085A1).

The reactor has an entrance tube with a coiled tube heat exchanger. The center of the tube coil has a ceramic reradiating body.

The feed gas passes through the coil heat exchanger. The preheated feed gas flows to the top in the outer annulus of the reactor vessel. It is further heated by the electrical heating elements. The hot gas then goes down to the center in the middle of the annulus and is heated by the electrical heating elements.

The extremely hot syngas enters the coil heat exchanger through a port located in this heat exchanger bottom plenum. The hot syngas transfers heat to the feed gas and preheats it. The cool syngas exits the bottom plenum through a pipe.

Raven chemical

Raven’s steam/CO₂ reforming system produces H2 and Fischer-Tropsch liquids, as depicted by the diagram below.

Raven SR steam/CO2 reformer system for Fischer-Tropsch process.
Raven SR steam/CO2 reformer system for Fischer-Tropsch process (ref. US20220017826A1).

The system comprises:

  • receiving feedstock into an initial reformer;
  • reforming at least a portion of the feedstock in the initial reformer with steam to produce an input gas, wherein a portion of the input gas is syngas;
  • transferring the input gas from the initial reformer to a main reformer;
  • reforming the input gas in the main reformer with steam to increase the amount of syngas;
  • transferring the syngas from the main reformer to a Fischer-Tropsch module;
  • using the syngas in a Fischer-Tropsch reaction;
  • and extracting from the Fischer-Tropsch module H2O and at least one of Fischer-Tropsch liquids generated by the Fischer-Tropsch reaction and H2 generated by the Fischer-Tropsch reactions.

Efficient use of steam/CO₂ reforming requires optimized process control parameters and recycling of reaction products to maximize the production of hydrogen and Fischer-Tropsch products.

These process control parameters include the temperature of steam/CO₂ reforming and the addition of steam, CO, and biogas. Optimized parameters can result in 50-57% H₂ production, removal of sulfur and halogen contaminants, and desired H₂/CO ratio for Fischer-Tropsch reaction.

Increasing the temperature to 871 °C or adding biogas can increase H₂ production. Also, for all feedstocks, there is an optimum addition of both steam and CO₂ which would provide a range of H₂/CO ratio from 2.0 to 3.0. The ratio of 2.3 is optimal for the Fischer-Tropsch reaction.

Raven SR Patent

  • US8858900 Process and system for converting waste to energy without burning
  • US20200048085A1 Electrically heated steam reforming reactor
  • US20220017826A1 Production of hydrogen and ft products by steam co2 reforming
  • US20220062846A1 Compact and maintainable waste reformation apparatus
  • US20220162509A1 Process and system for duplex rotary reformer
  • US20220169927A1 Production of renewable fuels and energy by steam/co2 reforming of wastes

Raven SR Technology Applications

Hydrogen production

The technology can produce hydrogen-rich syngas that is 55-65% hydrogen, which is higher than most processes, including plasma arc gasification. This hydrogen-rich syngas can be converted into renewable energy products including hydrogen.

Fischer-Tropsch synthetic fuels

The hydrogen-rich synthetic gas can also be converted into Fischer-Tropsch synthetic fuels (diesel, Jet A, mil-spec, JP-8), additives, and solvents (such as methanol, butanol, and naphtha).

Sustainable aviation fuel (SAF)

Raven SR has signed a memorandum of understanding (MOU) to supply SAF to All Nippon Airways (ANA) for major global routes. The SAF is produced from the company’s Fischer-Tropsch process.

Waste-to-hydrogen projects

The company has organic waste-to-hydrogen projects in Aragón, Spain and in Richmond, California. These projects aim to convert organic waste into clean hydrogen, reducing greenhouse gasses ,and contributing to the global hydrogen transition.

Raven SR Products

Raven S-Series

Raven S-Series unit on site converts various waste to hydrogen and Fischer-Tropsch synthetic fuels, such as sustainable aviation fuel (SAF) using non-combustion steam/CO₂ reforming process. The process is designed to be carbon-neutral, and depending on the feedstock, the renewable fuels can have zero to negative carbon intensity. The company’s technology is modular and scalable.

Raven G-Series

The Raven G-Series unit is a modular, gas-to-gas system that can produce 4,500 kg of hydrogen per day from renewable or natural gas. It is designed to utilize stranded gas, low methane, or otherwise unmonetized gas to create hydrogen affordably and efficiently. The units can be placed on landfills or stranded natural gas wells and have a conversion efficiency of over 97%, compared to 75% for traditional steam methane reforming.

Raven Fischer-Tropsch synthetic fuels

Raven’s Fischer-Tropsch synthetic fuels are produced through the Fischer-Tropsch process, which involves reforming syngas to create fuels out of hydrogens and carbons. These synthetic fuels, such as diesel, Jet A, Jet B, and milspec JP-8, are higher in purity and burn more cleanly than traditional hydrocarbon fuels.

The company’s technology first converts various feedstocks, including biomass, municipal solid waste, bio-solids, industrial waste, sewage, medical waste, and methane, into hydrogen-rich syngas. The syngas allows for the production of higher volumes of both hydrogen and synthetic fuel from the feedstock. The resulting Fischer-Tropsch synthetic fuels have higher energy content per carbon and can be used in a variety of applications, including sustainable aviation fuels (SAF) and renewable diesel.

Raven SR Funding

Raven has raised a total of $21.8M in funding over 5 rounds:

Their latest funding was raised on Jul 25, 2023 from a Venture-Series Unknown round.

The funding types of Raven.
The funding types of Raven SR.
The cumulative raised funding of Raven.
The cumulative raised funding of Raven SR.

Raven SR Investors

Raven is funded by 7 investors:

Rock Creek and Stellar J Corp are the most recent investors.

The funding rounds by investors of Raven.
The funding rounds by investors of Raven.

Raven SR Acquisition

Raven has acquired Benicia Fabrication & Machine on Dec 1, 2021.

Raven SR Founder

Matt W. Murdock is Founder.

Raven SR CEO

Matt W. Murdock is CEO.

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