Process For Converting Carbonaceous Material Into Low Tar Synthesis Gas
AssigneesExpander Energy Inc., Air Technic S.R.O.
InventorsSteve KRESNYAK, Pavel ZAHORIK
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Abstract
A continuous multi-stage vertically sequenced gasification process for conversion of solid carbonaceous fuel material into clean (low tar) syngas. The process involves forming a pyrolysis residue bed having a uniform depth and width to pass raw syngas there through for an endothermic reaction, while controlling the reduction zone pressure drop, resident time and syngas flow space velocity during the endothermic reaction to form substantially tar free syngas, to reduce carbon content in the pyrolysis residue, and to reduce the temperature of raw syngas as compared to the temperature of the partial oxidation zone.
Claims30
A continuous multi-stage vertically sequenced gasification process for conversion of solid carbonaceous fuel material into clean (low tar) syngas in a gasifier comprising:
- i) a pyrolysis zone,
- ii) a partial oxidation zone located vertically downstream of the pyrolysis zone, and separated from the pyrolysis zone via a separation member comprising a plurality of upwardly angled vents;
- iii) a reduction zone located vertically downstream of the partial oxidation zone and comprising an angled perforated floor, one or more openings located centrally relative to the perforated floor, and a centrally located deflector;
- the floor being sloped downward and inward toward the one or more openings, wherein the perforated floor is configured, by sizing of perforations therein, to primarily allow passage of syngas therethrough, and to inhibit passage of the pyrolysis residue obtainable in the pyrolysis zone;
- said process comprising the steps of:
- a) feeding the carbonaceous fuel material through the upper portion of the pyrolysis zone vertically downward towards the lower portion of the pyrolysis zone, while pyrolyzing the fuel into pyrolysis vapours comprising hydrocarbon material, and raw pyrolysis residue comprising char and ash;
- b) optionally adding a first oxidant to the lower portion of the pyrolysis zone to achieve a temperature greater than 200° C.;
- c) directing the pyrolysis vapours to the partial oxidation (PDX) zone, and directing the pyrolysis residue downwardly to the reduction zone via the separation member;
- d) adding a second oxidant in the partial oxidation zone to achieve a temperature sufficient to reform the pyrolysis vapours into raw syngas containing significantly reduced levels of tar;
- e) forming a pyrolysis residue bed having a uniform depth from the raw pyrolysis residue formed in step c) on the floor of the reduction zone;
- f) passing the raw syngas from step d) downward through the raw pyrolysis residue bed formed in step e), and carrying out an endothermic reaction between CO2 and/or H2O in the raw syngas and carbon of the char in the pyrolysis residue bed, while controlling the reduction zone pressure drop, resident time and flow space velocity of the raw syngas during the endothermic reaction to form substantially tar free enhanced syngas and a decarbonized pyrolysis residue;
- g) passing the substantially tar free enhanced syngas from step f), in upward counter-current flow, to heat the pyrolysis zone and subsequently cool the substantially tar free enhanced syngas;
- h) collecting the enhanced syngas;
- and
- i) collecting the decarbonized pyrolysis residue from the bottom of gasifier.
An apparatus for a continuous multi-stage vertically sequenced gasification process for conversion of solid carbonaceous fuel material into clean (low tar) syngas, the apparatus comprising:
- i) a pyrolysis zone for converting the fuel into pyrolysis vapours comprising hydrocarbon material, and carbon rich raw pyrolysis residue comprising char and ash;
- ii) a partial oxidation zone located vertically downstream of the pyrolysis zone for conversion of the hydrocarbon material in the pyrolysis vapours into raw syngas comprising H2, CO and CO2;
- iii) an endothermic reduction zone located vertically downstream of the partial oxidation zone for converting the raw syngas into enhanced syngas and for reducing carbon content of the raw pyrolysis residue to obtain decarbonized pyrolysis residue;
- iv) a separation member located between the pyrolysis zone and the partial oxidation zone,
- the separation member comprising a plurality of upwardly angled vents to allow the pyrolysis vapours into the partial oxidation zone and to inhibit passage of the raw pyrolysis residue therethrough, and the separation member being configured to direct the pyrolysis residue into the reduction zone;
- v) an outlet port for the decarbonized pyrolysis residue, located downstream of the reduction zone;
- vi) an outlet for the enhanced syngas located downstream of the reduction zone;
- vii) the reduction zone comprising an angled perforated floor, one or more openings located centrally relative to the perforated floor, and a centrally located deflector,
- the floor being sloped downward and inward toward the one or more openings, and configured by sizing of perforations therein, to allow primarily passage of the raw syngas therethrough towards the outlet for the enhanced syngas and to inhibit passage of the raw pyrolysis residue, and the one or more openings being in fluidic communication with the outlet port, and configured to allow passage of the decarbonized pyrolysis residue therethrough.
Dependencies are inferred from the claim text.