Theme: 01. Remediation Technology Innovations

Topic Area: 01q. Electrical Resistance Heating: Best Practices and Lessons Learned

Formatted Title:

Power Delivery: Why It Matters

Background/Objectives:

Achieving target power input is one of the strongest performance indicators for thermal treatment systems. Site models predict the total energy needed to achieve the remedial goals, based upon predicted power input and estimated heat losses. Power input must be high enough to offset site heat losses. Power input values measured during operations provide an instantaneous snapshot of thermal system performance. Achieving target power input throughout a thermal remediation typically results in meeting remedial goals within or ahead of the predicted schedule and budget.

Throughout a thermal implementation, power input may change based upon subsurface conditions making individual electrode/heater power monitoring a critical aspect of system optimization.

Approach/Activities:

This presentation will cover how power input impacts subsurface conditions, determines heat-up rates, and, in turn, the speed of thermal treatment implementations. Thermal system design approaches, key data collection, and system operation guidelines will be described to maximize site power input across thermal treatment technologies. The focus will be on comparing power input for electrical resistance heating (ERH) and thermal conduction heating (TCH), the two leading technologies for dense non-aqueous phase liquid (DNAPL) source removal.

Results/Lessons Learned:

To appropriately design for target power, an understanding of site conditions is necessary for realistic duration, power and energy usage predictions. Through comparing modeled power predictions versus actual power input achieved, the required power input and duration are identified for a site, based upon thermal operations data collected from numerous remediations across thermal technologies. Recent design advances and methods used to maximize power input will be described, with site case studies covering methods and approaches to maximize power delivery. We will discuss maximum power input for different thermal technologies and how these limitations affect the choice of heating method. We will also discuss site conditions where groundwater flow must be reduced or accounted for, and when the use of steam injection is beneficial.

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Eric Maki