This product system model represents the generation of two co-products from forest or wood product mill operation residues using the Tucker Renewable Natural Gas (RNG) Thermochemical conversion process. The two co-products are a synthesis gas (syngas) and biochar (a form of charcoal made from woody biomass via pyrolysis, used as a soil amendment, and under investigation as an approach to carbon sequestration to produce negative carbon dioxide emissions). As of August 2016, the Tucker RNG process is operational as a pilot scale project in Charlotte, North Carolina. A duplicate Tucker RNG process is designed to take place in St. Regis, Montana along with a chip operation sawmill where the feedstock provided. A wood chip production unit process will be released with a subsequent version of this data set.

The Tucker RNG process uses high-temperature (>750°C) thermochemical conversion in a low oxygen environment to convert feedstock from forest thinning and mill residues into syngas, which can be used for heat and electricity, and co-product biochar for soil amendment or as a precursor in the manufacturing of activated carbon and other industrial carbon products. The system minimizes the introduction of atmosphere using a double air lock coupled with a feedstock compression system that expels interparticulate air from the feedstock before heating. This being an endothermic process, three propane burners are fired to provide heat to the active chamber. The feedstock was transferred into the active section in which the temperature was kept from 750°C to 870°C for pyrolysis reaction. After about 1.5 minutes reaction in the active chamber, the generated biochar and high molecular chained syngas were transferred to a passive section with no external heat source but further reaction with a specific catalyst assistant to produce more low-molecular-chain syngas. Syngas leaving the passive section was then cooled in a tar condenser and a misting chamber to removed oil and tars. The emissions from the Tucker RNG unit conversion were not measured at the test, therefore not accounted for. Only operational data, such as feedstock input, utility use and heat source are measured or calculated to model the process. A more complete description of the Tucker RNG process can be found in Gu and Bergman (2016). See full citation below.

Data for this process were collected in St. Regis, Montana and Locust, NC, where the Tucker RNG conversion process has been tested and demonstrated.

This record was modified on 05/10/2018. The two unit processes previously published were compiled into a product system and the product system model is now available.