The description describes the integration of a gas fermentation process with a gasification process whereby effluent from the gas fermentation process is recycled to the gasification process. The one or more effluents which can be recycled include a stream comprising microbial biomass, a product stream comprising at least a portion of the at least one fermentation product, a by-product stream comprising fusel oil, and a waste water stream comprising microbial biomass. The stream comprising biomass can be dried before it is passed to the gasification zone. At least a portion of the waste water stream can be passed to the gasification process where one use is to replace at least a portion of the process water. The waste water stream can be further processed to produce a clarified water stream and a biogas stream comprising methane either or both of which can be passed to the gasification process.

Methods and systems for processing construction and demolition (C&D) materials to produce a product gas stream and/or electricity are disclosed herein. In some embodiments, the method comprises pre-processing C&D materials to produce a C&D feed, and processing the C&D feed to produce syngas. The C&D feed can comprise untreated wood, treated wood, paper and cardboard, yard waste, plastic, rubber, and/or foam. Processing the C&D feed can comprise gasifying the C&D feed, steam, and oxygen in a gasifier at a temperature of no more than 950° C. and/or a pressure of no more than 200 psi to produce syngas.

Pre-ground plastics of small particle size not more than 2 mm are co-fed into a solid fossil fuel fed entrained flow partial oxidation gasifier. A syngas composition can be made by charging an oxidant and a feedstock composition comprising recycle plastics and a solid fossil fuel to a gasification zone within a gasifier; gasifying the feedstock composition together with the oxidant in said gasification zone to produce said syngas composition; and discharging at least a portion of said syngas composition from said gasifier; wherein the recycled plastics are added to a feed point comprising a solid fossil fuel belt feeding a grinder after the solid fossil fuel is loaded on the belt, a solid fossil fuel belt feeding a grinder before the solid fossil fuel is loaded onto the belt, or a solid fossil fuel slurry storage tank containing a slurry of said solid fossil fuel ground to a size as the size fed to the gasification zone.

The present invention is directed to a dry tomb landfill for biological carbon sequestration, and more particularly to a dry tomb biolandfill having biomass enclosed by top and bottom seals containing at least one barrier to water transport, a covering layer that functions to protect the enclosed biomass from atmospheric disturbance, one or more accessible pipes or conduits connected to the enclosed biomass, and means to monitor biomass decomposition of the enclosed biomass

Pre-ground plastics of small particle size not more than 2 mm are co-fed into a solid fossil fuel fed entrained flow partial oxidation gasifier. High solids concentrations in the feedstock stream can be obtained without significant impact on the feedstock stream stability and pumpability. A consistent quality of syngas can be continuously produced, including generation of carbon dioxide and a carbon monoxide/hydrogen ratio while stably operating the gasifier and avoiding the high tar generation of fluidized bed or fixed bed waste gasifiers and without impacting the operations of the gasifier. The subsequent syngas produced from this material can be used to produce a wide range of chemicals.

A combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) system and process are described that convert various biomass-containing sources into separable bio-oils and aqueous effluents that contain residual organics. Bio-oils may be converted to useful bio-based fuels and other chemical feedstocks. Residual organics in HTL aqueous effluents may be gasified and converted into medium-BTU product gases and directly used for process heating or to provide energy.

Pre-ground plastics of small particle size not more than 2 mm are co-fed into a solid fossil fuel fed entrained flow partial oxidation gasifier. High solids concentrations in the feedstock stream can be obtained without significant impact on the feedstock stream stability and pumpability. A consistent quality of syngas can be continuously produced, including generation of carbon dioxide and a carbon monoxide/hydrogen ratio while stably operating the gasifier and avoiding the high tar generation of fluidized bed or fixed bed waste gasifiers and without impacting the operations of the gasifier. The subsequent syngas produced from this material can be used to produce a wide range of chemicals.

Pre-ground plastics of small particle size not more than 2 mm are co-fed into a solid fossil fuel fed entrained flow partial oxidation gasifier. High solids concentrations in the feedstock stream can be obtained without significant impact on the feedstock stream stability and pumpability. A consistent quality of syngas can be continuously produced, including generation of carbon dioxide and a carbon monoxide/hydrogen ratio while stably operating the gasifier and avoiding the high tar generation of fluidized bed or fixed bed waste gasifiers and without impacting the operations of the gasifier. The subsequent syngas produced from this material can be used to produce a wide range of chemicals.

Pre-ground plastics of small particle size not more than 2 mm are co-fed into a solid fossil fuel fed entrained flow partial oxidation gasifier. A syngas composition can be made by charging an oxidant and a feedstock composition comprising recycle plastics and a solid fossil fuel to a gasification zone within a gasifier; gasifying the feedstock composition together with the oxidant in said gasification zone to produce said syngas composition; and discharging at least a portion of said syngas composition from said gasifier; wherein the recycled plastics are added to a feed point comprising a solid fossil fuel belt feeding a grinder after the solid fossil fuel is loaded on the belt, a solid fossil fuel belt feeding a grinder before the solid fossil fuel is loaded onto the belt, or a solid fossil fuel slurry storage tank containing a slurry of said solid fossil fuel ground to a size as the size fed to the gasification zone.

Pre-ground plastics of small particle size not more than 2 mm are co-fed into a solid fossil fuel fed entrained flow partial oxidation gasifier. A syngas composition can be made by charging an oxidant and a feedstock composition comprising recycle plastics and a solid fossil fuel to a gasification zone within a gasifier; gasifying the feedstock composition together with the oxidant in said gasification zone to produce said syngas composition; and discharging at least a portion of said syngas composition from said gasifier; wherein the recycled plastics are added to a feed point comprising a solid fossil fuel belt feeding a grinder after the solid fossil fuel is loaded on the belt, a solid fossil fuel belt feeding a grinder before the solid fossil fuel is loaded onto the belt, or a solid fossil fuel slurry storage tank containing a slurry of said solid fossil fuel ground to a size as the size fed to the gasification zone.