Electromagnetic Induction Heaters for Selective Soil Remediation
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Solution Overview
Problem
Current soil heating technologies for remediation and hydrocarbon recovery are limited by small heating surface area, difficulty in controlling vertical temperature gradients, and inability to achieve high soil temperatures necessary for effective remediation of contaminants with high boiling points, while also incurring significant sunk costs due to non-recoverable heating equipment.
Innovation Solution
A conductive casing with an insulated conductor generates a magnetic field inducing a current that increases resistance and heat through the skin-effect, allowing for selective heating of different vertical extents and recoverable equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If electric heater elements or combustion pipelines are used for soil heating, then heating capability is achieved, but the heating surface area is limited due to cost considerations restricting diameter size
Solution Approach 1:
The patent replaces conventional electric heater elements and combustion pipelines with an electromagnetic induction system. A conductive casing (heater element) is positioned in the wellbore, and a conductor wrapped around the casing generates an alternating magnetic field that induces eddy currents in the casing, heating it through resistive heating. This substitution enables larger diameter casings to be used as heater elements, significantly increasing the heating surface area without the cost constraints of conventional electric heating elements or combustion pipelines.
2Ease of repair
If conventional heating equipment is used, then heating function is provided, but the equipment becomes sunk costs as it is typically left in the ground after remediation
Solution Approach 1:
The patent designs the heating system with recoverable components. The conductor (coiling assembly) wrapped around the conductive casing can be removed and reused for subsequent remediation projects. Only the conductive casing itself remains in the ground, while the expensive electrical components and conductor are recovered, eliminating the sunk cost issue associated with conventional heating equipment that must be abandoned.
3Ease of operation
If electric current is passed through heater elements or combustion is used, then soil heating is achieved, but selective heating of different vertical extents to different temperatures is difficult to control
Solution Approach 1:
The patent divides the heating system into multiple independently controllable segments. The conductor is wrapped around the conductive casing in multiple sections, with each section capable of being independently energized. This segmentation allows different vertical extents of the wellbore to be heated to different temperatures by controlling which conductor sections are active, providing precise temperature control without complex additional equipment.
4Temperature
If electric current is passed through soil between electrodes, then heating is generated through Joule heating, but the soil temperature is limited to the boiling point of water which is insufficient for certain contaminants
Solution Approach 1:
The patent introduces a conductive casing as an intermediary between the electromagnetic field and the soil. The casing acts as a dedicated heating element that concentrates electromagnetic energy into resistive heating, achieving much higher temperatures than direct Joule heating of soil. This intermediary approach enables temperatures well above the boiling point of water, making the system versatile for remediating contaminants with high boiling points that cannot be addressed by conventional electrode-based Joule heating.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides efficient, selective heating with high temperatures and a larger heating surface area, reducing costs by allowing recovery of heating equipment, and achieving efficient remediation and hydrocarbon mobilization.
Implementation Method 1
the conductor is configured to generate at least one magnetic field when the at least one driving current is supplied thereto to create at least one corresponding induced current in the casing
Implementation Method 2
the at least one induced current to encounter resistance in the casing to increase the temperature
Implementation Method 3
the conductor is configured to generate at least one magnetic field when the at least one driving current is supplied thereto to create at least one corresponding induced current in the casing
Data Source
AI summary
A heating device for heating underground soil comprising a work-coil housed in a conductive casing, wherein when at least one driving current is supplied to the work-coil, whereby the work-coil generates at least one magnetic field that induces at least one induced current in the casing. The driving currents are of a frequency sufficiently high to cause the induced currents to generate resistance in the casing, thereby increasing the temperature of the casing. A plurality of the heating devices may be arranged in an array to facilitate the heating of a zone of soil.