SGH2 Energy ($5M for plasma biomass gasification)

SGH2 Energy focuses on producing green hydrogen through the gasification of waste. They are the only company with this solution and have built the world’s largest green hydrogen plant. The company aims to fuel a clean energy future with greener than green hydrogen. SGH2 Energy has a project in Los Angeles that will supply hydrogen to fuel cell electric vehicle refueling stations.

Challenges: biomass gasification

According to the American biochemical engineer Patrick Kenji Takahashi, hydrogen (H₂) is a “simple solution” to address the world’s energy problems and needs. Hydrogen is the most abundant element in the universe and the simplest element on the periodic table. For its use as an energy carrier, it must be separated from hydrocarbons (e.g., methane CH₄) or water (H₂O). In fact, the overall thermal efficiency of converting hydrogen to electric energy required by a fuel cell electric vehicle (FCEV) is three times greater than the thermal efficiency of burning this liquid fuel to power today’s internal combustion engine vehicles. Utilizing hydrogen in this manner may significantly contribute to global energy security.

The majority of the world’s hydrogen (over 60 million tons) is currently produced via steam methane reforming (SMR) process, which requires a significant amount of energy input and emits a substantial amount of CO₂. The SMR process emits between 5 and 9 tonnes of CO₂ per tonne of hydrogen produced. Electrolysis of water by using renewable electric power produces green hydrogen without emitting CO₂. However, electrolysis requires 50 kWh of energy to produce 1 kg of H₂ which only gives 33 kWh of energy. 35% of the original input power is wasted. The cost of electrolysis-produced hydrogen is higher than that of SMR-produced hydrogen. In addition, the capacities of currently available electrolyzers are inadequate as they are useful for small scale production only.

Both economically and technically, the gasification of abundantly available biomass to produce green hydrogen may be a cost-effective method.

SGH2 Energy Technology

SGH2 Energy has developed a plasma enhanced gasification reactor for the low-cost production of green hydrogen from abundant biomass waste materials, such as recycled paper, organic waste, purposely grown energy crops, and wood.

SGH2 Energy’s gasifier is distinct from other plasma gasification reactors. The plasma gasification reactor of SGH2 Energy is integrated with a low-cost oxygen absorber system that can generate oxygen enriched air (90% to 95%) to ensure that the syngas product contains no unconverted hydrocarbon molecules, such as tars. Other plasma gasification reactors use oxygen from a secondary supplier at very high cost or from a dedicated air separation unit that employs expensive cryogenic technology to separate air.

In addition, SGH2 Energy’s plasma gasification reactor uses a biochar catalytic bed in the oxidation zone, whereas other reactors use metallurgical or petroleum coke. The biochar material consists of a dense carbon char that consumes at a much slower rate than the biomass feedstocks to be gasified as a result of the very high fixed carbon fraction of the carbon char.

Gasifier

The diagram below depicts SGH2 Energy’s plasma gasification reactor integrated with a low-cost oxygen absorber system.

There are three zones in the plasma gasification reactor: a thermal cracking plenum zone, a double bed zone, and a vitrification zone.

The thermal cracking plenum zone has a particular geometric shape that allows the complete thermal crack of hydrocarbons into syngas. The top of this zone is equipped with at least one syngas gas exit port.

The upper portion of the double bed zone has multiple inlets for the introduction of biomass material. The lower portion of the double bed zone is equipped with a gas inlet system that supplies oxygen enriched air produced by the oxygen absorber system. The lower portion of the double bed zone also has a number of tuyeres where plasma arc torches are mounted to increase the heat generated by the biochar carbon catalyst bed and biomass bed to create an operating temperature between 3,000 and 5,000 ºC.

The vitrification zone has one or more tap holes to tap the molten lava produced by the reaction of inert materials within the feedstocks with flux materials containing silica (SiO₂) and calcium oxide (CaO).

The specific geometric funnel shape of the gasifier and the rate of rising gas from the torches and other gas inlets are designed to ensure a low superficial velocity of the rising hot gas, allowing the entering biomass feed to completely descend into the biomass bed without being forced upward. In addition, the thermal cracking plenum zone allows all hydrocarbon materials such as tars to be exposed to the high temperature with a residence time of 2-3 seconds before they exit the gasifier. The complete thermal cracking of hydrocarbons produces CO and H₂.

How does the gasifier work?

During operation, the gasifier is continuously fed shredded and compacted biomass material. Plasma torch plumes continuously warm the biochar carbon catalyst bed at the bottom of the plasma gasifier, forming a uniform flow of hot gas upwards. As the cold biomass feeds are continuously fed into the gasifier, they form a uniformly distributed biomass bed on top of a previously heated consumable biochar carbon catalyst bed at the bottom of the gasifier. The descending cold biomass and the rising heated gas from the catalyst bed create a counter-current flow, which allows the complete stages of reaction from oxidation, to partial oxidation to devolatilization and drying zones of the biomass uniformly across the reactor and its vertical zones.

The controlled introduction of oxygen-enriched air produced by the integrated low-cost oxygen absorbent system into the gasifier can generate up to 4,000 ºC at the bottom of the gasifier to generate a controlled partial oxidation reaction of gasification that will generate an optimal syngas with higher calorific content and higher volume of hydrogen while reducing the specific energy requirement, i.e. the energy consumed by the plasma torches to gasify the biomass. In turn, this increases the net efficiency of the gasification of organic biomass for the hydrogen production.

The biomass bed is continuously reduced by the rising hot gasses from the consumable biochar catalyst bed and continuously replenished by the feeding system in order to maintain the bed height. This sequence results in a temperature gradient from at least about 4,000 ºC at the bottom of the gasifier to at least about 1,200 ºC in the exit syngas outlet. The rising counter-current system thus established serves to dry the incoming biomass and thus allow the system to handle a biomass stream with moisture content of up to 90% without causing shutdown, as is the case with other thermal combustion systems. In general, the high moisture content of the biomass feed would result in a syngas with a lower heating value and less hydrogen production because the biomass feed contains a lower hydrocarbon content.

The syngas produced in the gasifier at atmospheric pressure is then extracted, cleaned of impurities and acid gasses, and cooled to a lower temperature. This process generates high pressure steam, which is used to maintain the temperature of the integrated oxygen absorber system operating between 450 ºC and 550 ºC.

The resulting scrubbed, cleaned, and cooled syngas contains approximately >65 vol. % H₂ and <35 vol. % CO, which is then compressed and fed into a water gas shift system together with pressurized water vapor to convert most of the CO and H₂O into additional H₂ and CO₂. The off-gas from the water gas shift reactor contains mostly hydrogen gas, along with traces of CO, CO₂, sulfur-containing compounds, and other impurities. The off-gas is processed in a pressure swing adsorption (PSA) unit in order to purify hydrogen at industrial scale. The purified hydrogen gas is compatible with fuel cell systems used in transport vehicles.

The molten pool of inorganic material at the bottom of the gasifier is tapped continuously out of the gasifier via slag taps. The slag materials can be used for construction materials.

SGH2 Energy Patent

US20220081629A1 Methods, processes and systems for the production of hydrogen from waste, biogenic waste and biomass
WO2022056456A1 Methods, processes and systems for the production of hydrogen from waste, biogenic waste and biomass

SGH2 Energy Products

SGH2 energy is launching the world’s largest green hydrogen production facility in Lancaster, California. The Lancaster facility will be able to process 40,000 tons of biomass waste annually and produce 3,800 tons of green hydrogen per year.