Online Measurement of Elemental Yields, Oxygen Transport, Condensable Compounds, and Heating Values in Gasification Systems

Abstract

Biomass gasification produces a wide range of species, from permanent gases to condensable hydrocarbons, with different composition and boiling points. This complicates the mass balance of the system, as multiple techniques are needed to quantify the various components of the produced raw gas. In this study, a high-temperature reactor for thermal conversion of raw gas at 1700 °C was developed to generate a gas stream that consisted primarily of CO, CO2, H2, and H2O. The reactor was experimentally evaluated and subsequently used for measurements of the raw gas from the Chalmers 2-4–MW dual fluidized bed gasifier. The gas stream that exits the reactor is analyzed to obtain the total elemental flows of C, H, O, and N, which facilitate determinations of the fuel conversion and oxygen transport in a dual fluidized bed reactor. The proposed system was operated in parallel with a gas-cleaning system, to determine the yield of condensable species, including tar and GC-undetectable species. A simplified approach is proposed for quantifying the average energy content of the condensable species, thereby allowing the wet raw gas efficiency and lower heating value (LHV) to be calculated.

Advanced biofuel production via gasification – lessons learned from 200 man‐years of research activity with Chalmers’ research gasifier and the GoBiGas demonstration plant

“…This has been possible thanks to the advances in raw gas characterization methods, which include: He tracing to derive the total yield of gas ; Gas Chromatography for measurement of the concentrations of permanent gases; and SPA method for characterization of aromatic tar . More recently, the development of a High Temperature Reactor (HTR) provided an independent method to quantify the total carbon in the raw gas . The HTR enabled the closure of the carbon balance of the Chalmers gasifier, as well as the validation of an improved SPA method .…”

“…For online tar monitoring, spectroscopic methods, such as laser‐induced fluorescence and UV‐vis spectroscopy have demonstrated the ability to give reliable responses for a shift in the tar composition toward larger molecules . Even measurement after a high temperature conversion of a slip stream to assess the overall carbon amount gives information about the yield of condensable hydrocarbons . For alkali species, spectroscopic methods are under development but are not yet ready for application .…”

Experimental Investigation of Volatiles–Bed Contact in a 2–4 MWth Bubbling Bed Reactor of a Dual Fluidized Bed Gasifier

“…The total yields of carbon ( , ), hydrogen ( , ), and oxygen ( , ) in the raw gas were derived from the measurements. Detailed descriptions of the reactor design, measurement technique, and mass balance calculations are provided elsewhere 33 .…”

Mechanism and Kinetic Modeling of Catalytic Upgrading of a Biomass-Derived Raw Gas: An Application with Ilmenite as Catalyst

“…However, for benzene, naphthalene, and methane, the estimated value ranges for the rate constants were derived from other studies; , Carbon deposition on the ilmenite particles was negligible in the excess steam environment, and therefore, it was not considered; , The formation of CH m O n from CO and H 2 was ignored under the conditions used in this study, i.e., S gas = 0; While the values of p i most likely change as the tar and light HC gradually evolve, to simplify the calculations, these values were assumed to remain constant during the evolution of tar and light HC in relation to gas–solid contact time; For the destruction of tar and light HC, the effect of catalysis was greater than the thermal effect at 800 °C; In the raw gas and reformed gas, HC in the range of C 4 –C 5 carbons were neglected. Thus, group C7 consisted of only C 2–3 H y ; ,, Unknown tars refer to compounds identified in the gas chromatograph-flame ionization detector (GC-FID) analysis but at very low levels, and thus not included in the standard tar compounds predefined in the GC-FID method. Additionally, these unknown tars were assigned to the most plausible known tar groups based on their retention times in the GC-FID chromatograms. …”