Systems and methods for converting carbonaceous fuels

A system for converting carbonaceous fuels comprising a gaseous fuel conversion reactor, a solid fuel conversion reactor, a fuel pretreatment fluidized bed reactor disposed between the gaseous fuel conversion reactor and the solid fuel conversion reactor, an oxidation reactor disposed downstream of the solid fuel conversion reactor, and a pretreatment gas-solids separation unit;

• the gaseous fuel conversion reactor comprising:
• a gaseous fuel reactor oxygen carrier solid inlet,
• a gaseous fuel reactor off-gas inlet configured to receive off-gas from the fuel pretreatment fluidized bed reactor, and
• a gaseous fuel reactor oxygen carrier solid outlet,
• wherein the gaseous fuel conversion reactor is configured to convert the off-gas and oxygen carrier solids to a product gas stream comprising carbon dioxide and water, thereby reducing at least a portion of the oxygen carrier solids to reduced oxygen carrier solids;
• the fuel pretreatment fluidized bed reactor comprising
• a pretreatment reactor solid fuel inlet disposed in a fuel introduction section of the fuel pretreatment reactor,
• a pretreatment reactor oxygen carrier inlet configured to receive a mixture of oxygen carrier solids and reduced oxygen carrier solids from the gaseous fuel reactor oxygen carrier solid outlet,
• a pretreatment reactor intermediate gas inlet configured to receive intermediate gas from the solid fuel conversion reactor, the intermediate gas being used for fluidization, and
• a pretreatment reactor discharge in communication with the gaseous fuel conversion reactor off-gas inlet,
• wherein the fuel pretreatment fluidized bed reactor is configured to volatilize solid fuel using heat from the mixture of oxygen carrier solids and reduced oxygen carrier solids to produce a devolatilized solid fuel and off-gas, and subsequently discharge the off-gas, the devolatilized solid fuel, and the mixture of oxygen carrier solids and reduced oxygen carrier solids via the pretreatment reactor discharge;
• the solid fuel conversion reactor comprising:
• a solid fuel conversion reactor inlet configured to receive the mixture of oxygen carrier solids and reduced oxygen carrier solids and devolatilized solid fuel from the pretreatment reactor discharge,
• a solid fuel conversion reactor intermediate gas outlet in communication with the pretreatment reactor intermediate gas inlet, and
• a solid fuel conversion reactor oxygen carrier solid outlet,
• wherein the solid fuel conversion reactor is configured to react the devolatilized solid fuel with the mixture of oxygen carrier solids and reduced oxygen carrier solids to produce the intermediate gas comprising carbon dioxide and water, thereby further reducing oxygen carrier solids to reduced oxygen carrier solids;
• the oxidation reactor comprising:
• a reduced oxygen carrier solid inlet configured to receive the reduced oxygen carrier solid and
• an oxidation reactor discharge configured to discharge the oxygen carrier solid and an oxygen depleted oxidation gas stream,
• wherein the oxidation reactor is configured to react the reduced oxygen carrier solids from the solid fuel conversion reactor oxygen carrier solid outlet with an oxidation gas stream to convert the reduced oxygen carrier solid back to the oxygen carrier solid;
• and
• wherein the pretreatment gas-solids separation unit is in communication with the pretreatment reactor discharge and configured to separate the off-gas from the devolatilized solid fuel and the oxygen carrier solid exiting the fuel pretreatment reactor.