Aug-2021

Distill produced water using waste heat with low-temperature distillation technology

The Low-Temperature Distillation technology is a patented, award-winning technology licensed in Canada to Integrated Sustainability by Crystal Clearwater Resources.

Yves Matson
Integrated Sustainability

Article Summary

This cutting-edge technology is a low-temperature and low-pressure desalination process to treat challenging and variable saline wastewater that cannot be treated economically by traditional means. CCR has partnered with Integrated Sustainability to both mature the technology in demonstration and pilot projects, as well as market this new method of produced water treatment to the Canadian energy sector. Integrated Sustainability has committed to bring its 100-person water-focused company as part of CCR’s technical development team, supporting CCR’s strategy for bringing innovative, best-in-class treatment to the North American energy sector.

First of its kind
The LTDisTM technology is a step-change, clean technology innovation that works towards balancing a carbon neutral economy and sustainable resource management while encouraging economic growth and diversification. This technology can utilise low grade waste heat to provide up to 100% of the thermal load creating a significant operational cost advantage over other thermal and membrane solutions.

LTDisTM resolves many challenges of traditional desalination technology including high capital cost, significant thermal or electrical input requirements, low water recovery, and high GHG emissions. The modular and standardised design also allows for plant sizes to be scaled up or down to meet the demand of clients’ needs.

Waste heat application
The LTDisTM technology uses low grade heat to evaporate saline water and recover fresh water by employing an adaptive process that utilises self-correcting vacuum pressure settings and internal circulation to maintain a thermodynamic balance in response to changing external variables. This makes LTDisTM ideally compatible with waste heat and solar thermal energy as alternatives to hydrocarbon-based energy sources for desalination.  

LTDisTM does not require extensive contaminant pre-treatment in comparison to other thermal and membrane technologies. The use of low-grade heat and high circulation rates prevents scaling on heat transfer equipment that has plagued other evaporative solutions. Solids formed within the system are removed in the brine reject stream and contaminants of concern to operations, such as hydraulic fracking, are concentrated into either brine or non-condensable gas streams. The concentrated brine stream can then be injected into an existing disposal well, and the non-condensable gases can be sent to existing gas management equipment on site.

Alternative to chemical dosing
Thermodynamic properties, not chemical reaction rates, drive the distillate recovery, allowing the LTDisTM technology to operate over a larger range of feed water quality than most alternative solutions. Performance is not impacted by changes in feed water quality during operation. This flexibility makes it a good fit for produced water, which changes from well to well, and the technology is transferrable between facilities, applications, and industries with very little customisation required.

Cost savings and environmental benefits
The LTDisTM unit can reduce the need for stranded capital in inground produced fluid conveyance pipelines and storage infrastructure. Using waste heat to power the LTDisTM unit results in a minimal operations cost, and in some cases, there is a [90%] reduction in comparison to traditional desalination technologies. Ultimately, deployment of this technology will substantially reduce the cost structure and GHG footprint for water management in the energy and industrial wastewater sectors.

LTDisTM can significantly reduce GHG emissions because waste heat can be used as the thermal energy source for the process. A conceptual model that estimates the GHG emissions generated in the treatment of 20,000 bbl/d of wastewater using LTDisTM technology, compared to a generalised direct contact evaporation technologies, was completed.

As shown in the figure above, in a sample case study, direct contact evaporation technologies generate nearly 79,000 tCO₂e/yr from its evaporation, desalination, and power requirements alone. Conversely, LTDisTM uses waste heat produced at the site, only generating carbon dioxide through its electrical energy demand, resulting in the generation of just over 3,200 tCO₂e/yr.

In this case study representing typical waste heat found at gas processing facilities, it amounts to an estimated yearly CO₂e savings of 95% when LTDisTM is used instead of other direct evaporation technologies.

GHG emissions reductions are not the only environmental benefits that the LTDisTM unit provides. The unit is also impactful in the following ways:
· Decreasing the volume of water lost from the water cycle when sent to disposal
· Reducing the need for freshwater withdrawal from the environment
· Reducing the strain on already limited disposal injection formations
· Decreasing the risk of over pressurisation of injection wells leading to induced seismicity by decreasing disposal volumes
· Reducing produced water trucking to help alleviate stakeholder concerns including traffic and road wear
· Reducing the use of and disposal of water treatment chemicals
· Treating water to beneficial reuse specifications that allow for release into many more suitable uses beyond only hydraulic fracturing reuse