FRESH WATER MAKER
UD-2-85 TWO STAGES VACUUM DISTILLER
INTRODUCTION
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SILIARIS has a partnership with Expander Manutenção Company, located in São Paulo-SP, Brazil, specialist in manufacture of thermal exchange equipment and also with Cabraltec Company located in Tubarão-SC, Brazil, where the final assemblies and tests are carried out.
With diffrent production capacities, Siliaris distillers process sea water and produce high quality fresh water continuously for the supply of oil offshore platforms, ships and rigs, as well as for onshore installations. The evaporative energy comes from waste heat recovery from thermal machines or from the vapor produced in boilers.
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SILIARIS UD-2-85 two stages, UD-1-60 and UD-1-40 one stage model
TECHNICAL DESCRIPTION OF SILIARIS SEA WATER DISTILLERS
The technological innovation of SILIARIS distillers is characterized by the concentric arrangement of heat exchangers, which save space and avoid steam pipes. This constructive model makes the equipment more compact, facilitating installation and, associated with the upward evaporation system, has provided excellent heat exchange coefficients and high productivity.
Designed according to each site specific conditions, the equipment has a control panel with automatic operation system, using confident analyzers, and a field recorder that memorizes the operational data which helps in the analysis of the performance of the machine.
Construction:
Siliaris distillers are provided in one or two stages, skid mounted, assembled in a patented concentric arrangement, which allows its compactness, due to the tubular exchangers specially designed to allow this configuration. The machine is supported on bearings that permits rotation up to 90º for easy access to the bottom of the evaporator in an horizontal disposition, allowing safety and efficiency for inspection and maintenance.
Shell and tubesheet are manufactured in 316L stainless steel, with excellent resistance to sea water. Tube material is aluminum brass, also very resistant to brines and with excellent thermal exchange.
All accessories, such as pumps, panel, flow lines and instruments are assembled in such a way to allow free access for maintenance and operation.
Process:
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Feed water:
SILIARIS distillers do not require filters for the inlet sea water. Any suspended solids, which may be present in the feed water, are automatically eliminated in the brine waste, by the combined air and brine eductor.
Free chlorine eventually present in the feed water is not a concern, since these volatile molecules are easily eliminated with the temperature and the vacuum in the evaporative chamber.
Tightness:
SILIARIS distillers use seals that guarantee total tightness, without loss of vacuum, which improve heat exchange and therefore provide good efficiency and productivity. All parts are assembled in such a way to avoid leakages, that are the most inconvenient causes of mal functioning in a vacuum machine, and sometimes very difficult to find.
Quality and Control:
Produced water quality is granted by ancillaries internal parts, specially designedand tested, such as deflectors, mist eliminators and other parts, that work as a barrier to avoid salt water content in the vapor. In case of fresh water salinity exceeds required parameters, an automatic disposal is activated to reject this water, until values come to pre adjusted conditions.
Main parameters of the unit, such as temperatures, flowrates, production and salinity are recorded in a data logger register, for the analysis of operational evolution, and to help to identify any eventual disturbance in the process.
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Distillers accessories:
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Eductor with combined brine and non-condensables rejection, is machined with alternative engineering materials, resisting very well to erosion and corrosion, works for a long span of life, without waste. The ejector nozzles can be replaced if necessary, depending on process conditions. Eductor has an auxiliary vacuum socket for general use.
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Bearings to support the machine, that allow the rotation in 90º to facilitate opening for inspection and maintenance.
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One destilate pump and one chemical dosing pump dedicated for each stage.
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Special lifting frame for the upper chamber (containing the condenser), with an eye centered on the equipment's CG.
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Zinc sacrificial anode, installed submerged in the bottom cover, easy to replace, when necessary.
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Independent outlets at each stage for adding acids for chemical cleaning, or adding fresh water for washing or hibernation.
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Level display in the first stage distillation chamber for operational assistance.
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Schedule 80 PVC valves and lines, which guarantee durability and total leak tightness.
Instrumentation:
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Salinity monitor: automatic rejection system, which monitors the quality of the water produced online, with a three way pneumatic valve, actuated by an electrical solenoid.
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Analisador, transmissor e controlador de salinidade de fabricação nacional, microprocessado, com uma saída de corrente de 4 a 20mA para registro e leitura de dados, e duas saídas de contato. Grau de proteção IP67. Possui indicação local e display iluminado alfanumérico de duas linhas com indicação também da temperatura do destilado. Possui certificados de calibração e ISO 9001.
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Microprocessed salinity analyzer, transmitter and controller, with a current output 4 to 20mA for online reading at the IHM and registration, and two contact outputs. Degree of protection IP67 with illuminated alphanumeric display of two lines with indication also of the distillate temperature. ISO 9001 certified.
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Electromagnetic distillate flow meter, with teflon coating and 316L stainless steel electrodes, IP67 degree of protection, with illuminated LCD display and cast aluminum housing. It also measures the accumulated volume and has a current output 4 to 20mA, for online reading at the IHM and registration. ISO 9001 certified.
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<>·PT100 electronic temperature transmitters in the evaporators, two at the hot water system and two at the condenser, connected to the data logger and displayed on the IHM. These records are very important for performance diagnosis.
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Electric:
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Painel montado conforme norma NR-10, com botão de parada em emergencia, sistemas de proteção para todos os componentes, com tomada elétrica auxiliar para lap tops e ferramentas elétricas de pequeno porte. Na tampa do painel estão as botoeiras e luzes indicativas de estado das bombas, inclusive de falhas, e a IHM do registrador de dados;
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Panel assembled according to brazilein NR-10 standard, with emergency stop button, protection systems for all components, with auxiliary electrical outlet for lap tops and small electrical tools. On the panel cover are the buttons and lights indicating the status of the pumps, including failures, and the data recorder's HMI
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Voltage 440V, 380, 220V
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Groundings to all pumps, painel and skid.
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Materials:
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Shell, nozzles and flanges: stainless steel inox 316L
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Tubes: alluminum brass UNS C68700
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Tubesheets: stainless steel inox 316L
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Sea water, brine, distilate and non condensable lines: schedule 80 PVC
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Painting:
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External paint (shell and skid): two-component epoxy paint, cured with high-thickness polyamide and resistant to temperature, abrasion and weather. The external painting has the purpose to protect the inox 316L of contamination by eventual iron residues (pitting).
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Internal painting: no internal coating is required inside the machine. 316 L stainless steel has high corrosion resistance, with excellent durability.
Operation:
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After startup and suitable process adjustments, according to the operation manual, the distiller operates continuously and unassisted. Only one operator is enough for starting and stopping the machines, with all of its controls at the front to allow a complete view of the operating parameters, without having to leave the front of the control panel and the HMI.
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All optional data is recorded on the computer installed inside the electrical panel. Periodically, the data must be collected for the elaboration of graphs and trends that helped in the decision making of the correct moment for the execution of acid cleanings. Data collection can be done via a lap top or USB stick, and it takes a few seconds to download the entire history. The recorder signals the completion of the collection operation, which can also be performed remotely over an ethernet or internet network.
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Shut down operation is very simple and is basically done in the inverse way of starting. If the machine is stopped for a longer period, the hibernation operation must be performed, flushing inside with fresh water.
S Second stage evaporation takes place with the latent heat of condensation of the vapor generated in the first stage. Thus, a two-stage model produces twice as much as a single-stage model, with the same energy consumption, in a low grade temperatures in the range of 50 to 60ºC. Vacuum is obtained through the use of eductors, drived by the discharge of the seawater leaving the condenser, allowing a long term and dependable running period, with a minimum downtime for acid preventive cleaning.um
Acid cleaning:
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Siliaris distillers do not need specific CIP (Cleaning In Place) system with tank and dedicated pumps. On this way it is not necessary to disconnect flanges and install extra hoses for acid cleaning.
Through a specific nozzle on the seawater feed lines (blue arrows in the picture), the vacuum system sucks fresh water directly from a hose, and, through the glass sight, the operator fills the vessel until the correct level. Acid is added in sequence at the same nozzle, just connecting a small hose inside the acid gallon, and the vacuum does the rest. After the acid insertion, a small quantity of air is permitted to enter in the vessel at the same nozzle, for mixture
agitation, which bubbles inside the evaporators. This air forces the acid mixture to move constantly through the tubes until PH becomes high enough to stop, or to repeat the operation. Air and CO2 resulting from the chemical cleaning reaction, are normally eliminated through the vacuum outlet of the respective stages.
PH control is done collecting samples directly from specific nozzles in the evaporators.
This procedure makes the cleaning operation simpler, safer and more efficient, optimizing operational and downtime costs.
It is expected to have one cleaning duty each 15 running days of operation.
Maintenance:
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It is recommended every year of operation, the opening of the distiller for general inspection of the fixation and cleaning of accessories, such as deflectors and mist eliminators, If necessary, as a preventive way to preserve the heat exchange capacity and restore the productivity of the evaporators, it is possible to perform a mechanical cleaning inside the tubes by pneumatic tools, which eliminate the salt residues that have adhered to the tube wall, which not always are completely eliminated in routine acid cleaning operations.
The 90º rotation of the machine over its two bearings, allows full access to the bottom, as shown in the picture. Mechanical cleaning restores the "as new" production conditions, and starts a new span of operations.
The two-stage distiller has a hydraulic piston in the lower shell that lifts and rotates the upper chamber, giving full access to the second stage.
In the center of this piston there is a support that holds a lifting system with a ratchet, which facilitates the removal of the second stage, without the need for hoists or scaffolding, which are often not available. This system makes maintenance services safer and faster, in addition to reducing labor costs and prolonged downtime.
In case of a one-stage distiller, there is only the ratchet-lift system for removing the condenser, since it does not have the upper chamber.
The preventive maintenance routine duties are listed in the machine maintenance manual, such as re-tightening of screw connections, vacuum tightness test, cleaning of conductivity sensor, etc.
Included spare parts:
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1- Evaporators and condenser gaskets.
2- Eductor rubber seals.
3- Second stage rubber seal.
4- Two eductor nozzles.
5- Sacrifice anode.
6- Two 200mm sight glasses.
7- Two 100mm sight glasses.
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Special accessories included:
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1- Lifting frame of upper chamber.
2- Lifting device of condenser or second stage.
3- Special tool for loosing and tightning glass sights.
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Optional spare parts recommended:
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1- Second stage evaporator and respective vessel test.
2- Condenser and respective vessel test.
3- Distilate pump.
4- Chemical dosing pump.
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