Veolia Water Solutions & Technologies
L'Aquarène
1, place Montgolfier
94417 Saint-Maurice Cedex
France
Tel.: +33 (1) 45 11 55 55
Fax: +33 (1) 45 11 55 80
POLARIS is equipped with integral jacket pre-heaters for maximum thermal efficiency and minimal piping. Conventional systems use separate external pre-heat exchangers connected via external pipework. Each POLARIS MED column is equipped with an integral jacket pre-heater with unique flow path control, providing direct heat transfer with the main vessel and limiting external pipework to a few centimetres and only two connections per vessel. The result is optimised heat recovery, cost effective design and simplified maintenance.
POLARIS uses Double Tube Sheet Heat exchangers for maximum heat transfer and ultimate process security. The energy required for the phase change in the first phase from purified feed water to pure steam is provided by industrial steam. The double tube sheet design of the POLARIS heat exchangers ensures that the industrial steam cannot come into contact with either the purified water or pure steam.
The POLARIS falling film heat exchanger design maximises the efficiency of the evaporation process. Pre-heated purified feed water is fed to the multi-tube heat exchangers in an ultra-thin film, producing an instantaneous'flash' evaporation effect that both maximises heat transfer efficiency and enables rapid start-up.
POLARIS uses an innovative separation system to ensure complete water droplet removal in each effect. Efficient droplet removal is a critical step in pyrogen removal, which is the critical process in WFI production. Since pyrogens are non-volatile they can only be carried by water droplets, once the feed water has been turned to steam. By effectively removing any entrained water droplets using a novel process based on differential kinetic energy, POLARIS provides the ultimate pyrogen removal security.
The final step for ultimate WFI purity. POLARIS uses double tube sheet multiple tube heat exchangers in the final purification step for maximum purity and optimised heat transfer efficiency.
POLARIS VCD is equipped with Double Tube Sheet heat exchangers for eliminating contamination risk between the feed water inlet and the water for injection, whilst optimising heat recovery from the outgoing WFI and also from the waste gases produced by the gas removal device. POLARIS VCD integrates the WFI cooling system producing distilled water between 25°C and 90°C depending on customer needs.
POLARIS VCD can use two different heating sources - steam and electrical heating - these can be used independently or combined depending on customer preference. This system is used to continuously maintain the operating temperature at boiling point.
The heat exchanger is the heart of the system where the balance between condensation and the evaporation feeds the system with as much energy as is required to keep the evaporation process'alive'. POLARIS VCDhas minimised the energy consumption thanks to the advanced design of its heat exchanger. In this process step, gas removal also takes place, maintaining the optimum WFI conductivity.
This part of the distillation process is responsible for pyrogen and bacteria removal, the most critical area of WFI microbiological quality. In POLARIS VCD, the contaminants are released from the vapour in the water droplet separator by close control of the shear and speed ratio between the vapour and any water droplets present.
The vapour compressor increases the pressure and consequently the temperature of the pure steam. The purpose of this stage, is to optimise the energy balance of the distiller. The POLARIS VCD compressor uses all sanitary components and an optimised seal design to ensure the highest possible steam quality. The POLARIS VCD always operates at a positive pressure differential relative to the surroundings, making ingress of contaminants impossible.
The last fraction of contaminant elements is separated from the steam condensate through WFI re-circulation. In POLARIS VCD, the re-circulating pump also maintains the WFI outlet pressure.
POLARIS uses Double Tube Sheet Heat exchangers for maximum heat transfer and ultimate process security. The energy required for the phase change from purified feedwater to clean steam is provided by industrial steam or electricity. The double tube sheet design of the POLARIS heat exchanger ensures that the industrial steam cannot come into contact with the clean steam.
The POLARIS evaporation column design maximises the efficiency of the evaporation process. Saturated steam generated into the heat exchanger expands into the evaporation column, and then separates under gravity, into gas and water droplets. The proportions of the POLARIS evaporation column are perfect for optimising this separation process.
The POLARIS water droplet separation system ensures complete water droplet removal across the full range of operating conditions. Efficient droplet separation is a critical step in pyrogen removal, which is the critical process in clean steam production. Since pyrogens are non-volatile they can only be carried by water droplets, once the feed water has been turned to steam. By forcing the steam to rapidly change direction in a'tortuous path' chamber, shear is maximised, and the droplets are stripped from the clean steam, providing the ultimate pyrogen removal security.
Perfect operating conditions are maintained due to continuous water circulation between the evaporation column and the heat exchanger (tube side). This process eliminates low flow zones and maximises the thermal efficiency of the continuous evaporation process.
Compliance to CS requirements thanks final quality control. Having produced high quality clean steam, POLARIS is equipped with and EN285 sampling device that uses a tube in tube heat exchanger to condense the clean steam, and a validated conductivity meter to measure the condensate quality.
The first step for ultimate Clean Steam purity. POLARIS uses a clean steam operated device to strip out uncondensable gas from the feed water avoiding carry over of impurities that could compromise the final clean steam quality.
Optimised heat recovery for maximum efficiency. Conventional CSG systems introduce cold feed water, via external pipework, directly into evaporation chamber. The POLARIS CSG column is equipped with an internal feed water manifold which enters the column from the top, pre-heating the feed water prior to entering the boiling area.
POLARIS shares a common control system architecture and software design with the other VWS Critical Water Utilities system components, allowing easy integration for complete Purified Water and WFI systems. Access to the PLC based control system is via a colour touch screen HMI. The graphic display screens are intuitive and easy to navigate. Options include 21 CFR part 11 compliance and panel mounted PC SCADA.