Process for purification of contaminated water
Inventors
Berns, JR., Henry C. • Church, David L. • Knapke, Michael J. • Moeller, Daniel • Rossin, Joseph A.
Assignees
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Publication Number
US-10934177-B2
Publication Date
2021-03-02
Expiration Date
Abstract
Various embodiments may include a system for removing contaminants from contaminated water comprising: a distillation still supplying heat to contaminated water to boil the contaminated water; a vent allowing a vapor stream to exit the distillation still; an oxidation unit removing additional contaminants from the vapor stream; an outlet discharging a purified water stream from the oxidation unit; and a heat exchanger transferring heat from the purified water stream leaving the oxidation unit to the vapor stream exiting the distillation still before the vapor stream enters the oxidation unit.
Core Innovation
The invention describes a system for removing contaminants from contaminated water by combining distillation with an oxidation unit. Contaminated water is boiled in a distillation still, and a vent allows a vapor stream to exit the distillation still. The vapor stream then passes to an oxidation unit for removing additional contaminants, and purified water is discharged from the oxidation unit.
A heat exchanger transfers heat from the purified water stream leaving the oxidation unit to the vapor stream exiting the distillation still before the vapor stream enters the oxidation unit. The document further describes embodiments in which the oxidation unit includes a thermal oxidizer or a catalytic reactor. In catalytic embodiments, a noble metal catalyst and an oxidation temperature range are used.
The background context addressed in the document is purification of contaminated water, including flowback water and produced water associated with hydraulic fracturing operations. The document also describes approaches for energy efficiency through heat recovery using the heat exchanger, and in some embodiments using a steam compressor to supply superheated steam to the distillation still.
Claims Coverage
The claims coverage centers on a single independent system claim with additional inventive refinements provided by dependent claims. Across the claim set, the inventive features relate to the distillation-plus-oxidation architecture, venting a vapor stream from the distillation still into an oxidation unit, using a heat exchanger for heat transfer between purified water and the pre-oxidation vapor stream, and dependent constraints specifying the oxidation unit type, catalytic temperature and noble metal catalyst, addition of air to the vapor stream prior to oxidation, and a steam compressor providing superheated steam to the distillation still. An additional dependent limitation restricts the contaminated water to hydraulic fracturing process water.
Distillation still vented to an oxidation unit
A distillation still supplies heat to boil the contaminated water, a vent allows a vapor stream to exit the distillation still, and an oxidation unit removes additional contaminants from the vapor stream.
Purified water discharge from the oxidation unit
An outlet discharges a purified water stream from the oxidation unit.
Heat exchanger heat transfer between purified water and pre-oxidation vapor
A heat exchanger transfers heat from the purified water stream leaving the oxidation unit to the vapor stream exiting the distillation still before the vapor stream enters the oxidation unit.
Thermal oxidizer for removing additional contaminants
The oxidation unit includes a thermal oxidizer.
Catalytic reactor with noble metal catalyst at 200°C to 600°C
The oxidation unit includes a catalytic reactor operated at a temperature between 200°C and 600°C using a noble metal catalyst.
Air added to the vapor stream prior to oxidation
The system includes an inlet that adds air to the vapor stream before the vapor enters the oxidation unit.
Downstream steam compressor supplying superheated steam
The system includes a downstream steam compressor supplying superheated steam to the distillation still.
Contaminated water comprising hydraulic fracturing process water
The contaminated water comprises process water from a hydraulic fracturing operation.
Overall, the claims define a heat-recovery distillation system that vents a vapor stream to an oxidation unit for additional contaminant removal, with dependent claims narrowing the oxidation unit to thermal oxidizer or catalytic reactor using a noble metal catalyst at a specified temperature range. Further dependent claims add air to the vapor stream prior to oxidation and include a downstream steam compressor supplying superheated steam to the distillation still, while also limiting the contaminated water to hydraulic fracturing process water.
Stated Advantages
Documented Applications
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