CASE STUDY
AddSorb™ OX20 for the US Biogas Market
In 2023, Jacobi launched our AddSorb™ OX series of coconut pellets as one of our first products under the Go Green initiative. The AddSorb™ OX series is designed to provide a high capacity for hydrogen sulphide (H2S) in an extruded coconut pellet for low pressure drop and exceptional handling characteristics during carbon exchange. This product targets existing coal-based products on the market for H2S removal, offering a sustainable alternative. Two standard grades are available:
- AddSorb™ OX20 – with a capacity of 0.2 g
H2S/cc, targeting the biogas market
- AddSorb™ OX30 – with a capacity of 0.3 g
H2S/cc,
targeting the municipal odour control market
In early 2024, Jacobi’s Americas region established contact with a major waste services provider that operates over 100 landfill gas treatment sites across the United States. Our introduction of AddSorb™ OX20 and its high H2S capacity in a sustainable product was well received, leading to a trial at one of their ‘problem’ landfill gas systems.
The Challenge
The landfill gas trial occurred at one of the customer’s sites on the West Coast of the United States. This particular site had a treatment system using a competitor’s granular coal-based carbon for H2S treatment prior to flaring. The gas conditions at this site were particularly challenging, with high spikes of H2S which contributed to frequent carbon exchanges, all of which led to disruption in the operation of the landfill. Furthermore, exchange of the competitor product was fraught with difficulty due to mechanical breakage and solidification (clumping) of the carbon granules, leading to extended downtimes to properly exchange the carbon.
The Solution
Several carbon adsorbers were previously installed at this site; one of the adsorbers was picked to run a side-by-side trial of AddSorb™ OX20 against the incumbent product. The landfill gas conditions highlight the operational challenges at this location:
OPERATING PARAMETERS
Flowrate 1300 SCFM
Temperature 82°F
Pressure 64 in W.C.
H2S Concentration 2000–4,000 ppmv
Methane 50.6%
Carbon Dioxide 38.2%
Oxygen 0.7%
Water (RH) 100% saturated
Balance (Nitrogen, Hydrogen, other) 10.5%
The Results
During the side-by-side trial, the competitor product showed immediate spikes of H2S in the adsorber effluent on the first day of the trial. In contrast, the AddSorb™ OX20 adsorber showed no effluent spikes and operated for a two-week period before breakthrough occurred and the carbon was exchanged.
At the conclusion of the trial, samples of each spent carbon (both the AddSorb™ OX20 and the incumbent coal-based product) were taken and tested for sulphur loading. This test indicated that the AddSorb™ OX20 met or exceeded the rated minimum capacity of H2S at the top and middle sample points within the bed (samples at the bottom tested at lower capacity, but this was expected due to incomplete saturation of the carbon near the exit of the vessel). This measured loading was over double the loadings measured on the competitor product.
Furthermore, the exchange of the spent AddSorb™ OX20 pellet proved to be quicker and easier, with less breakage and easier flowability of the carbon in pellet form. The competitor product again exhibited the solidification and clumping problems the customer had seen on previous exchanges.
All of these benefits were in addition to this customer lowering their CO2 footprint through use of a coconut-based material in place of the coal-based product they used previously. A clear success for the Go Green approach!