Methods and systems for oxidizing gas are provided. An example regenerative oxidizer is provided that includes a combustion chamber to heat gas present in the combustion chamber. The regenerative oxidizer also includes a first heat exchange media bed and a second heat exchange media bed. Each of the first heat exchange media bed and the second heat exchange media bed are in fluid communication with the combustion chamber. The regenerative oxidizer further includes two burners disposed within the combustion chamber to provide a total heat input to the gas present in the combustion chamber. At least one of the two burners is independently adjustable based on the airflow direction.

A process and apparatus for regenerating a spent acid stream or other stream, such as a spent acid stream or other stream containing sulfur, by decomposing the spent sulfuric acid stream and/or other sulfur-containing streams to recover sulfur dioxide from the stream. Also provided is a process for preparing sulfuric acid from the sulfur dioxide recovered by the apparatus and process.

A method for remediating a contaminated porous matrix including selecting the type and quantity of organic fuel to create a smolderable mixture of the organic fuel and contaminated porous matrix, and controlling the rate of oxidant addition to manipulate the relative proportions of oxidative breakdown products, non-oxidative breakdown products, and non-destructive remediation processes. The method further involves collecting the volatilized contaminant, and any gaseous breakdown products of the contaminant.

Methods and systems for oxidizing gas are provided. An example regenerative oxidizer is provided that includes a combustion chamber to heat gas present in the combustion chamber. The regenerative oxidizer also includes a first heat exchange media bed and a second heat exchange media bed. Each of the first heat exchange media bed and the second heat exchange media bed are in fluid communication with the combustion chamber. The regenerative oxidizer further includes two burners disposed within the combustion chamber to provide a total heat input to the gas present in the combustion chamber. At least one of the two burners is independently adjustable based on the airflow direction.

A method for remediating a contaminated porous matrix including selecting the type and quantity of organic fuel to create a smolderable mixture of the organic fuel and contaminated porous matrix, and controlling the rate of oxidant addition to manipulate the relative proportions of oxidative breakdown products, non-oxidative breakdown products, and non-destructive remediation processes. The method further involves collecting the volatilized contaminant, and any gaseous breakdown products of the contaminant.

A process and apparatus for regenerating a spent acid stream or other stream, such as a spent acid stream or other stream containing sulfur, by decomposing the spent sulfuric acid stream and/or other sulfur-containing streams to recover sulfur dioxide from the stream. Also provided is a process for preparing sulfuric acid from the sulfur dioxide recovered by the apparatus and process.

A process and apparatus for regenerating a spent acid stream or other stream, such as a spent acid stream or other stream containing sulfur, by decomposing the spent sulfuric acid stream and/or other sulfur-containing streams to recover sulfur dioxide from the stream. Also provided is a process for preparing sulfuric acid from the sulfur dioxide recovered by the apparatus and process.