Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - ZERO BRINE (Re-designing the value and supply chain of water and minerals: a circular economy approach for the recovery of resources from saline impaired effluent (brine) generated by process industries)

Teaser

The problem is posed with the brine feed into the pilot one facility. Where due to the high saturation of the brine it would exceed the concentration requirements of the brine resulting in a low process yield. To investigate this problem first a research was launched into the...

Summary

The problem is posed with the brine feed into the pilot one facility. Where due to the high saturation of the brine it would exceed the concentration requirements of the brine resulting in a low process yield. To investigate this problem first a research was launched into the steady state requirements of the pilot one facility. By conducting interviews with Lenntech B.V., the producers of the NF step of the pilot one facility, it was discovered that the NF requires a minimum of 25000 milligram per liter (mg/l) total dissolved solids (TDS) and a maximum of 50000 mg/l, with a concentration limit for the ionic particles within the brine composition. The lower the TDS the higher the separation yield of the NF, therefore a lower TDS is more desirable. Afterwards a research was launched into the transport of the brine to the pilot one facility. Due to the pilot one facility being constructed on the Huntsman Holland B.V. site and the high saturation of pipelines in the area it is not possible to construct a direct pipeline to the Pilot one facility. Therefore a transport system using a truck transport was developed. After evaluating all the presented transportation options and the transportation costs, the recommended transport option needs a buffer tank at the Evides DWP to provide a constant supply of the brine. The brine can then be transported using a forklift truck which can transport a tank to the pilot one facility. If the internal Huntman Holland B.V. contact is used the total costs of the transportation and storage option will be: €35.280,- per year.
on during the project.

Work performed

After the research into the storage and transportation of the brine, brine samples were analysed to research the resulting brine composition of a softener regeneration. The analyses showed that if peak concentrations were syphoned the resulting brine composition will exceed NF TDS maximums and therefore have a <1% yield. To achieve a brine composition that will meet the NF requirements the softener regeneration will have to be syphoned after the peak concentration. The recommended syphoning times are for a new IX-resin to start at t = 24 minutes when conductivity reaches between 76809 milli Siemens (mS) to 19878 mS until t = 34 minutes when conductivity reaches between 6895 mS to 4310 mS. For older IX-resin syphoning is to start at t =19 minutes when conductivity reaches 31805 mS to 19878 mS until t = 30 minutes and conductivity reaches 34700 mS to 21719 mS. Due to the recommended transportation system using a buffer tank at the Evides DWP location mixing can occur within the buffer tank. Mixing of different brine batches in the buffer tank results in the buffer tank acting as an equalizer for the resulting concentration. Due to the high concentration levels of the brine scaling is theorized to occur within the buffer tank as well.

The effect of mixing and the possible scaling was researched using the OLI software. The OLI software is capable of simulating fluid properties within aqueous systems. The simulations were executed using the analyses of the softener regenerations and brine samples. The simulations showed that the mixing would have a minor effect on the overall TDS of the system unless a high TDS stream was mixed. Scaling simulations showed that calcium carbonate (CaCO3) is very likely to show scaling and calcium sulphate (CaSO4) is likely to show scaling.

Final results

This report seeks to research what the pilot one treatment facility requires for steady state production and to design a system that is capable of meeting the steady state requirements. The first treatment step of the feed brine into the pilot one facility is the nanofiltration (NF) step designed by Lenntech B.V. The NF requires a minimum total dissolved solid (TDS) of 25000 g/m3 with a maximum TDS of 50000 g/m3. A high TDS causes the yield of the NF to be 1 m% and is therefore very inefficient, while a low TDS would have a NF yield of 41 m%. A low TDS is therefore more desirable even when target magnesium ion concentration would be lower.

The brine feed must therefore meet the NF TDS and concentration requirements. To achieve a brine composition that meets the NF TDS requirements brine samples from softener regeneration have been analysed using the Riemann sum approximation. A brine composition that meets the NF TDS and concentration requirements must be syphoned after the peak concentration during regeneration. Specifically it is recommended to syphon brine 5 minutes after peak concentration at time (t) = 24 minutes until t = 34 minutes for a newer IX-resin. The recommended syphoning for older IX-resins, which have a slower regeneration curve and later peak concentration, is to syphon the entire regeneration curve starting at t = 19 minutes until t = 30 minutes.

Each regeneration has a different concentration curve, therefore the softener regeneration will have peak concentration that vary per regeneration. It is therefore recommended to use an on-site composition analyse system to verify the brine composition. As Evides site one uses conductivity to measure brine composition, the final recommendation on the syphoning times are; To start with syphoning with newer IX-resins at t = 24 minutes when conductivity reaches between 76809 milli Siemens (mS) to 19878 mS until t = 34 minutes when conductivity reaches between 6895 mS to 4310 mS. For older IX-resin syphoning is to start at t =19 minutes when conductivity reaches 31805 mS to 19878 mS until t = 30 minutes and conductivity reaches 34700 mS to 21719 mS. It is recommended to perform conductivity measurements of the softener regenerations to calculate the true conductivity curve and reduce the conductivity range.

When the softener regeneration is syphoned it must then be transported to the pilot one treatment facility. The recommended transport option for transporting the brine uses a buffer tank located at the Evides site one location where it will hold 30 m3 of brine available for transport. The buffer tank will be rental and cost €30.000,- per year. A forklift truck will then transport a 20 m3 batch of this brine towards the pilot facility. Due to pilot one having a feed of 1 m3 per hour the 20 m3 will be able to provide brine for 2 and a half days of production, in theory only requiring two batches per week. This together with the transport contact by Huntsman Holland B.V. will have a total transport cost of €5.280,-. Resulting in a total transportation and storage cost of €35.280,-.

To simulate the brine mixing for scaling and the resulting concentration OLI simulations were made using the resulting brine compositions of the softener regenerations and sample data of the brine provided by the TU Delft. The OLI simulations showed that the brine will scale within the buffer tank. Specifically calcium carbonate (CaCO3) will show scaling and calcium sulphate (CaSO4) will be very likely to show scaling. The resulting concentrations if brine batches are mixed within the buffer tank show that unless a high concentration composition is already present the resulting TDS will not exceed the NF TDS and concentration requirements.

Website & more info

More info: https://zerobrine.eu/.