Implementing an Evaporator Crystallizer Plant: What Sets the SaltMaker Apart?

Apr 6th 2018

The SaltMaker MultiEffect evaporator crystallizer is a one-step brine treatment plant for volume minimization and zero liquid discharge (ZLD) applications. Its unique evaporative crystallizer design is built to treat the toughest waters and to simplify your brine treatment project.

Key Takeaways

The SaltMaker MultiEffect overcomes challenges that face conventional crystallizers:

  • Reliable solids production: A circulating slurry continuously forms and grows crystals. Solid salt is discharged to an automated bagging or binning system.
  • One-step treatment: No pre-treatment required. For ZLD applications, solids are produced without the need for extra process equipment, such as centrifuges or filter presses.
  • Resists corrosion, plugging, and scaling: High circulation rates, constantly changing saturation gradients, and non-corroding, non-stick wetted surfaces prevent reliability challenges that plague conventional crystallizers
  • Intelligent automation and self-cleaning: The plant has automated start, stop, and hibernate for immediate ramping from 0 to 25% capacity in one step. It operates at any capacity between 25% to 100% in dynamic capacity control mode and will detect and initiate cleaning cycles.
  • No single point of failure: The SaltMaker is built from redundant process sets. Even with the loss of one process set during maintenance, the plant keeps running at 92% capacity.
  • Modular build and scale-up: The plant is built inside ISO container frame modules for ease of delivery, installation, and expansion to suit growing project capacity needs by adding process blocks.
  • Low-temperature air humidification-dehumidification: The SaltMaker operates with an air cycle humidification-dehumidification process (< 90oC), which avoids the use of pressure vessels and enables its construction from fiber reinforced plastics that withstand severely corrosive fluids. Multiple effects efficiently recycle thermal energy, opening a wide range of waste heat energy source options.

Reliable Solids Production and Extraction

The SaltMaker MultiEffect produces solids by circulating a brine slurry to continuously form and grow crystals. Salts preferentially grow on nucleation sites of suspended seed crystals rather than on heat transfer surfaces. The larger crystals settle and are discharged to a Solids Management System for automated bagging or binning. Concentrated liquor, including smaller salt seeds, is recycled back to the SaltMaker while solid salts remain behind in the bags or bins. The system notifies the operators when the bags are full and ready to be transported to a drainage rack by forklift.

 

The solids are then drained and pass the paint filter test, often within 24 hours of draining, after which the bag can be sent for disposal or re-use depending on the application. The Solids Management System takes the guess work out of management and improves reliability. The plant flushes and purges slurry lines to prevent clogging, discharges thick slurry to the bags only when necessary, and automatically recycles rich liquor brine and notifies operators when to change bags.

Photo of SaltMaker's automated bagging system
Automated bagging system
Photo of a forklift carrying automatically bagged zero liquid discharge solids from a SaltMaker
Bag removed by forklift
Photo of a bag of solids as produced by a SaltMaker evaporator crystallizer
Bag of solids

One-Step Treatment

Traditional treatment technology requires multiple steps with different technologies to treat wastewater with high salinity levels. This includes separate systems for pre-treatment, evaporation, crystallization, solids production and dewatering. The SaltMaker combines these steps into a single system that requires no pre-treatment. It can be fed water at any salinity and almost any water chemistry. Expensive chemicals, such as soda ash, that increase solids load are avoided on the front end.

 

For ZLD applications, the Solids Management System can be added to the SaltMaker. Brine enters the plant, which produces freshwater and solids in bags or bins. No extra processing equipment, such as centrifuges or filter presses, is required. A simplified process flow diagram comparing the SaltMaker and a conventional process used to achieve ZLD is provided below.

Process flow diagram showing a conventional ZLD process
Process flow diagram showing a conventional ZLD process
Process flow diagram showing a SaltMaker MultiEffect ZLD process
Process flow diagram showing a SaltMaker MultiEffect ZLD process

Built to Resist Corrosion, Plugging, and Scaling

The SaltMaker MultiEffect is predominantly built from plastics—namely gel-coated, fiber-reinforced plastics—with a low surface energy that provides resistance to corrosion and scale. The photos below showcase the different components of the SaltMaker.

 

The plant also operates with high circulation rates to provide scouring flows, and all wetted surfaces are exposed to continuous dynamic salinity gradients for salt saturation relief. Combined with sound engineering design, the SaltMaker prevents plugging and challenges in reliability that frequently affect conventional evaporators and crystallizers.

Photo of pipework in a SaltMaker evaporator
Pipework:
UPVC and CPVC
Photo of pumps and engineered plastics in a SaltMaker evaporator crystallizer
Pumps:
Engineered Plastics
Photo of SaltMaker modules and tanks
Modules & Tanks:
Fiber Reinforced Plastics
Photo of a heat exchanger in a SaltMaker evaporator crystallizer
Heat Exchanger:
Titanium (non-boiling)

Intelligent Automated Operation and Cleaning

The SaltMaker MultiEffect has intelligent automated operations and self-cleaning processes. The plant can perform the following functions automatically: (1) start, (2) stop and flush, and (3) hibernate in circulation mode and ramp to 25% capacity in one step. Dynamic capacity control allows the SaltMaker to operate anywhere from 25% to 100% of rated capacity while being remotely managed via a secure internet connection.

 

The plant’s self-cleaning modes prevent irreversible scaling or fouling by regularly monitoring key performance metrics. It will then automatically trigger the appropriate level of cleaning, from ‘light rinse’ to ‘heavy scrub’. The SaltMaker uses distilled water as the cleaning fluid, which can be chemically augmented based on the type of scaling compounds and foulants in the brine. The wash solution is reused multiple times before being fed back to the SaltMaker for treatment once the fluid has been spent.

No Single Point of Failure

Unlike mechanical vapour recompression (MVR) technologies, where 100% of plant capacity is lost when the vapour compressor goes offline, the SaltMaker has no single point of failure. The plant is built with repeatable and redundant evaporation-condensation process sets. If a process set is down for maintenance, the plant continues to run at 92% capacity.

Photo of an evaporation module in a SaltMaker evaporator crystallizer
Evaporation module
Photo of a radiator module in a SaltMaker evaporator crystallizer
Radiator module
Photo of a fan module in a SaltMaker evaporator crystallizer
Fan module

An Evaporation-Condensation process set: There are multiple process sets in an effect

An image of an effect in a SaltMaker evaporator crystallizer
An Effect: There are multiple effects in a SaltMaker MultiEffect
Rendered image of an S100 SaltMaker MultiEffect with four effects
S100 SaltMaker MultiEffect with four effects

Modular Build and Scale Up

The SaltMaker MultiEffect is built into standard ISO container frames, which allow for ease of shipping, installation and future expansion. The open-concept design also allows for easy access to processing equipment, such as pumps, for inspection and routine maintenance, without the need for any confined space entry.

Photo of a modular SaltMaker MultiEffect plant as built into standard ISO frames
Modular SaltMaker plant built into standard ISO frames
A photo of SaltMaker process equipment with easy access
Easy access to process equipment
Photo of a SaltMaker evaporator effect
A SaltMaker evaporator effect

Multiple inspection ports (blue outlines in the photo above) in each effect allow for convenient monitoring of scaling and fouling. Process set modules slide in and out, and cleaning is done with a power washer.

 

The modular design simplifies transport and assembly. The SaltMaker is shipped by standard freight, without the need for any permits of oversized loads. The system is then assembled by crane onsite, as seen in the photos below.

Photo of a SaltMaker pilot system being assembled on-site, 1
Photo of a SaltMaker pilot system being assembled on-site, 2
Photo of a SaltMaker pilot system being assembled on-site, 3
Photo of a SaltMaker pilot system being assembled on-site, 4

SaltMaker MultiEffects are built to standardized plant sizes that can be added together to expand capacity as your project grows.

Model Capacity Based on Freshwater Removed*
m3/day Gallons/day Gallons/minute Barrels/day
S30 30 7900 5.5 188
S66 66 17400 12 415
S100 100 26400 18 630
S125 125 33000 23 790

* Capacity derated by 20% to produce a 450,000 mg/L total solids slurry and by 40% to produce solids.

Photo of a SaltMaker MultiEffect S100 plant
S100 SaltMaker MultiEffect plant: 100 m3/day freshwater removal capacity
Photo of an S100 and a S125 full-scale SaltMaker industrial wastewater treatment plants
S100 + S125 SaltMaker MultiEffect plants: Capacity increased by adding an S125 plant block: 100 m3/day + 125 m3/ day = 225 m3/day freshwater removal capacity

Low Temperature Air Humidification-Dehumidification

The SaltMaker MultiEffect is a multiple effect, thermally driven evaporator-crystallizer. It can use a variety of thermal sources: steam, low-grade waste heat, and gas or liquid fuel-fired low-pressure water heaters. It operates at atmospheric pressure and temperatures of less than 90oC, employing humidification-dehumidification air cycles that do not require a vacuum, pressure or boiling water on any heat transfer surfaces. Steam ticketed operators or pressure vessel certifications are not required.

 

In each of the effects, thermal energy is recycled, brine is concentrated, and freshwater is produced. Initial heat input to the plant at, for example, 92oC is used to evaporate and condense water in multiple effects, with the temperature being downgraded in each effect while the heat is recycled. This multiple effect process enables one unit of heat to produce four units of volume reduction, as shown the process diagram below. 

Process flow diagram showing internal workings of a SaltMaker MultiEffect evaporator crystallizer
Process flow diagram showing internal workings of a SaltMaker MultiEffect evaporator crystallizer

Warm brine flows at high volumetric velocities through the system, and is sprayed into non-stick packing material of the evaporator modules. Approximately 1–2% of each droplet is evaporated to become freshwater vapour, while the droplet is concentrated and cooled. The droplet is pumped through the system again to recapture heat and further evaporate.

 

Air is the vapour carrier, with the fan module providing the motive force. Water vapour condenses into freshwater liquid at the radiator modules, which also transfers the latent heat of condensation to the next effect for energy efficiency. The final effect can be open or closed to atmosphere, providing cooling and heat rejection.

 

As water is evaporated, the brine is concentrated. Solid salts form on smaller salt seeds as saturation is exceeded. The smaller salt seeds are recycled from the Solids Management System (SMS) described above, with larger crystals forming and then discharging back to the SMS. This continuous cycling enables salt crystal growth and prevents the need for complex multi-step processes. The SMS is seamlessly integrated into the SaltMaker process, controls, and modular skids, so a single package can be delivered and operated.

 

Contact us to see how the SaltMaker MultiEffect fits into your project.

About Saltworks

Saltworks Technologies is a leader in the development and delivery of solutions for industrial wastewater treatment and lithium refining. By working with customers to understand their unique challenges and focusing on continuous innovation, Saltworks’ solutions provide best-in-class performance and reliability. From its headquarters in Richmond, BC, Canada, Saltworks’ team designs, builds, and operates full-scale plants, and offers comprehensive onsite and offsite testing services with its fleet of mobile pilots.

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