2020-001 - Geoscience BC

Saltworks AirBreather Pilot

Lead Researcher(s): Saltworks Technologies Inc.

Project ID: 2020-001

Key Research Organization(s): Saltworks Technologies Inc.

Project Location: Northeast BC

Strategic Focus Area: Energy-Resources

Summary

This pilot project tested the AirBreather, a humidification-dehumidification technology (HDH) developed by Saltworks Technologies Inc. that harnesses waste heat from mechanical operations at natural gas production sites to treat highly saline wastewater (brine). The goal was to use waste heat to turn the brine into clean water for reuse or into water vapour that could be safely released into the atmosphere, resulting in zero liquid discharge (ZLD), as well as produce salt for industrial applications. This project was co-funded by Geoscience BC, the Canadian Natural Gas Association’s Natural Gas Innovation Fund Industry Grants and Sustainable Development Technology Canada.

The process was successful in producing water that met BC Aquatic Life Water Quality Guidelines. The solid salt produced was free of contaminants and met commercial quality standards for use as road salt, or industrial uses. The study found that brines with high sulphate levels could be processed using the AirBreather technology, however, the produced salts were too high in sulphate to meet industrial certification requirements. As a result, sulphate-rich produced waters are poor candidates for industrial salt production and re-use.

In assessing the technological process, it was determined that although the tested technology achieved net ZLD and clean salt production goals, the operational requirements were deemed too onerous to apply to full field deployment. The researchers therefore recommend forced-circulation, vacuum-based, evaporative crystallizer technology as a means of producing concentrated brines which would reduce the volume of water to be disposed of. There is some market in British Columbia for clean salt however research into additional markets or uses for the solid salt is recommended.

The Need

Approximately 87% of BC’s natural gas production is from the Montney Play in the Northeast Region. Natural gas and oil production co-produces a large volume of saline water that requires treatment and/or disposal. Disposing of the highly saline-produced water (formation water that flows to the surface with gas ) from Montney Play production is both challenging and expensive as much of the water must be trucked to disposal sites.

Energy companies spend approximately $180 million per year on a combination of ponding, reuse and transporting produced water from the Montney Play. This is expected to increase as the industry grows to meet forecast energy demand increases.

Project Goals

This Energy project fits under Geoscience BC’s Strategic Objective of Advancing Science & Innovative Technologies and our goal to:

Improve economic competitiveness of the Montney Play through advanced science and innovative geoscience technologies.

Specifically, this project involved:

Upgrading and commissioning the AirBreather pilot for zero liquid discharge (ZLD) operation with the objective of producing industrial salt for re-use;
Completing 20 days’ operation at Saltworks facility using representative water samples; and
Analyzing AirBreather pilot results, salts produced, salt reuse applications and economics to enable full-scale AirBreather AB-100 ZLD deployment.

Project Benefits

The AirBreather was designed to allow the capturing of waste heat on the production site and use it to reduce the volume of highly saline wastewater. This would either return clean water, which could be reused, or produce clean water vapour that operators could safely release into the atmosphere resulting in ZLD.

This made-in-BC technology would offer both financial and environmental benefits. AirBreather was estimated to offer 30% cost savings over traditional disposal methods. The reduction in water volume would mean fewer vehicles driving to and from production and disposal sites, leading to reduced emissions and improved safety.

Survey Area

Testing took place at Saltworks’ Richmond, BC, facility using produced water from a variety of locations in the Montney Play that were trucked from BC’s Northeast Region over several months.

What Was Found

The project focused on the treatment of Montney Formation produced waters with air humidification-dehumidification (HDH) evaporation technology. This enables use of heat generated by engine jacket or compressor jacket cooling water (a moderate 80-90 ^oC) to evaporate and treat saline water. At the pilot plant, propane was used to replicate the waste heat at the production site.

The liquid water produced after treatment was clean and met all BC Aquatic Life Water Quality Guidelines. Naturally occurring radioactive material in the brines was successfully pre-treated using sulphate to precipitate barium sulphate as a sludge that was removed.

Two of the three brine samples produced salt that met Transport Canada’s road salt specifications for >95% calcium-sodium chloride without ‘deleterious’ substances. The third sample produced salt that was too elevated in sulphate levels to meet these requirements. These purity requirements are also in place for other industrial applications such as the pulp and paper sector. The results showed that only waters with low sulphate levels would be suitable for industrial salt production.

Although the pilot technology achieved its solid salt production goals, the HDH technology is not recommended for widespread implementation of achieving ZLD at this time. It can however reliably produce a concentrated brine (30-40% salt solution) without significant operator intervention. To produce solid salt, a notable amount of operator attentiveness and continuous tuning of wash cycles is required to prevent scaling and crusting. This is deemed to be unsustainable by operators in the field. If HDH technology is used to generate concentrated brines, further investigation into the impacts of disposing of these brines into water disposal wells would be required.

As an alternative for ZLD of Montney-produced water in BC, it is recommended to use forced circulation vacuum evaporative crystallizer technology. However, the researchers also note that the cost of this technology is not currently commercially attractive when compared to the costs of produced water disposal.