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Hydrogen

Learn how FastOx gasification makes this potential “fuel of the future”.

Production

Hydrogen (H2) can be efficiently generated from the syngas produced by FastOx gasification. H2 is one of the easiest renewable products to be formed as the high-quality Syngas from FastOx systems contains around 25% by volume of H(exact quantities depend on feedstock used). These levels can be further improved via a water-gas shift (WGS) reaction and purification through Pressure Swing Adsorption (PSA).
 

During FastOx gasification, hydrogen is produced in the gasifier via two mechanisms. The first mechanism is the breakdown of organic matter in the absence of oxygen, which leads to the derivation of H2. The second mechanism is the reaction of the injected saturated steam, which produces additional H2. The contribution of both of these mechanisms result in a syngas that is–after cleaning–between 20-30% H2 by volume.
 

The H2 end product can be manufactured at any purity required by the project developer. For example, if the hydrogen product is intended for injection into a local Hydrogen pipeline it must be a minimum of 98% volume H2. If the H2 product is to be used in a proton exchange membrane (PEM) fuel cell, the H2 purity requirement is over 99.9% and with a maximum amount of carbon monoxide, CO, not to exceed 10 ppm.
 

Current hydrogen production facilities operate on large scales in a centralized manner. In contrast, FastOx gasification presents an opportunity to avoid the energy- and cost-intensive practices of preparing hydrogen for storage and transport. The scaling capability of FastOx gasification allows for small scale hydrogen production to be achieved in a distributed and localized manner.  This makes the widespread adoption of this fuel much more economically viable.

 

Impact/Potential

The production of hydrogen from waste materials via FastOx gasification can be deployed in small-scale, distributed production plants. These systems could be strategically positioned to solve multiple local municipal problems including the following:

  • Sourcing low-cost alternative distributed primary or peak shaving power where waste is generated
  • Demonstrate alternative H2 source in real-world conditions
  • Reduction in waste transportation
  • Reduction in greenhouse gas emissions from local landfills
  • Elimination and potential remediation of existing landfills
  • Production of carbon negative hydrogen source

 

One of the major concerns surrounding hydrogen gas is fuel storage and transportation. The storage of hydrogen gas requires either compression to high pressures (typically over 3,000 PSIG) or cooling and liquefaction, which reduces storage space.
 

Liquefying hydrogen gas into liquid H2 requires a significant amount of additional capital equipment. It also requires large amounts of energy to cool the gas to cryogenic temperatures (less than -253°C/-423°F). Once the liquid H2 is obtained, it can remain in that state only in pressurized and thermally-insulated containers. The amount of energy needed to produce and store liquid hydrogen is high due to the extreme conditions required for the substance to remain in the liquid state. The high energy requirements make this is a very expensive practice.
 

FastOx gasification is a technology that can accelerate the adoption of hydrogen feasible as a transportation fuel by solving several of the problems presented by liquefying hydrogen. These include a distributed generation-and-usage approach rather than larger scale liquefaction and long transportation routes. This is similar to our current system for production and usage of gasoline.
 

The potential for FastOx gasification in the production of hydrogen is significant. The output of hydrogen from FastOx gasifiers depends on many factors. These include the waste feedstock being converted, system configuration and other plant specifics. For a system processing post-recycling municipal solid waste materials, FastOx systems could produce 53-78 kilograms of hydrogen gas per metric ton of feedstock for small scale projects. That is the energy equivalent of 53-78 gallons of conventional gasoline.
 

Use our online calculator to see the hydrogen outputs for various waste materials and capacities.

 

Equipment

There are several system options for the processing of hydrogen. Several factors, including the desired use of the hydrogen and capital costs, must be considered when choosing the right Hproduction equipment.
 

To optimize hydrogen production, additional gas conditioning and preparation of the syngas is needed. Following the cleaning stage in the gasification isle, the syngas is transferred to the gas conditioning and preparation unit, where it is compressed and mixed with high-pressure saturated steam and fed into the Water-Gas Shift (WGS) reactor where the following reaction takes place over a readily-available catalyst:
 

CO + H2O → H2 + CO2

 

The amount of steam injected into the WGS reactor will be continuously controlled to maximize the hydrogen (H2) production while optimizing the life of the catalyst. The WGS reaction is mildly exothermic, and excess heat is removed from the shifted syngas with a waste-heat boiler (heat exchanger) that makes high-pressure steam, that is recycled into the process. Any excess, un-reacted steam leaving the WGS reactor, is removed via separators or knock-out pots, and is reused within the process.
 

Depending on the exact purity of hydrogen required by the project developer, the post-WGS gas can flow either:

  • To a hydrogen membrane module, followed by Pressure-Swing Adsorption (PSA);
  • To a CO2 removal process (the removed CO2 can be purified and sold as a commodity to local industries) before PSA; or
  • Directly to the PSA.

 

For the co-generation of H2 and another end-product such as electricity, it may be advantageous to separate the 20-40% volume H2 directly from the syngas in the low-pressure syngas header using a simple H2 membrane followed by PSA for high purities. Doing so leaves a CO-heavy syngas that can fuel an IC genset or gas turbine directly.
 

In summary, the equipment required–depending on the project–may include the following items:

  • Syngas compressor – raises the pressure of the syngas from 1.5 bar to the pressures required by the downstream equipment
  • Hydrogen membrane – separates hydrogen directly from the syngas
  • WGS reactor – converts excess CO into H2
  • PSA module – for final purification of the hydrogen to meet the hydrogen purity requirements of the end consumer, in this case 99.9% volume pure hydrogen for a fuel cell.