Multistage Distiller
With advanced control systems, originality of solutions, correct design, high reliability and extreme efficiency, our SMEF distillers are proving to be the most innovative solution in multiple effect still technology.
These plants are suitable for users looking for distillates for injectables of high chemical and pharmaceutical quality level. The design and construction reliability of the SMEF multi-stage distillers, together with the quality of the materials employed, ensures the equipment has a long life and is inexpensive and easy to maintain. If feed water meets with the relevant standards (absence of chlorine, silica, iron, amines and volatile substances) and the correct operating procedures are adhered to, SMEF distillers require virtually no maintenance.
SMEF Multistage distiller flow chart
Process description
Feed water enters the plant through the double tube sheet heat exchanger type DTS and enters the tubes of the exchanger, where the control system regulates, through pressure transducers, the level of the feed water inside the evaporation chamber of each column (B1, B2, B3, B4) of the distiller.
The industrial heating steam automatically enters the first exchanger through a modulating valve, bringing the feed water of the first column to evaporation point. The pure steam generated by this evaporation process is accurately separated from the water droplets and is filtered by a special designed separator. This separator is installed in the highest part of the column and has the fundamental task to completely separate the steam from entrained substance in the steam itself, making it "dry" and consequently sterile and pyrogen free.
The pure steam flows into the external side of the tubes of the heat exchanger of the second column, condensing into distilled water and at the same time bringing the feed water of the second column to boiling point again generating pure steam. This pure steam is again dried by the separator of the second column. The still water produced by the exchanger of the first column flows through the double tube sheet heat exchanger DTS. During this process, as a result of the feed water being in counter current, the temperature of the distillate is reduced.
The dry, pure steam of the second column, after flowing through the separator, enters the external side of the tubes of the heat exchanger condensing into distillate, again flowing to the exchanger. The process remains the same and is repeated in each column. The pressurised feed water enters the double tube sheet heat exchanger DTS, reducing the temperature of the distillate. The distillate then flows to a second double tube sheet heat exchanger DTS, as a result of the cooling water, the temperature is decreased to 85/95ËšC.
The pure steam flows into the external side of the tubes of the heat exchanger of the second column, condensing into distilled water and at the same time bringing the feed water of the second column to boiling point again generating pure steam. This pure steam is again dried by the separator of the second column. The still water produced by the exchanger of the first column flows through the double tube sheet heat exchanger DTS. During this process, as a result of the feed water being in counter current, the temperature of the distillate is reduced.
The dry, pure steam of the second column, after flowing through the separator, enters the external side of the tubes of the heat exchanger condensing into distillate, again flowing to the exchanger. The process remains the same and is repeated in each column. The pressurised feed water enters the double tube sheet heat exchanger DTS, reducing the temperature of the distillate. The distillate then flows to a second double tube sheet heat exchanger DTS, as a result of the cooling water, the temperature is decreased to 85/95ËšC.
Consumption
The SMEF Multistage Distiller is available with several distillation columns: the higher the number, the lower the consumption of the equipment.
Below is an example of the consumption of a 1.000 litre/h capacity, 5 effects SMEF distiller, with 8 bar industrial steam heating and an output of distilled water at 85/90ËšC:
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260 kg/h 1.100 litres/h demineralised water 400 litres/h softened water 1.5 kW/h (pump for pressurisation of feed water) |
Range of capacities
The SMEF has a range of capacities from 50 up to 7.000 litres/h, each model with from one, up to eight stages.
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Construction characteristics
Our SMEF equipment follows the strictest rules of all Pharmacopoeias and the guidelines of cGMP and the American Food & Drug Administration (FDA):Pressure vessel design in accordance with ISPE, ASME etc.
- The material of construction for all contact parts is totally AISI 316L stainless steel.
- All internal welds are TIG (Tungsten inert Gas).
- All internal parts, even those in contact with the feed water, are mirror polished and passivated.
- The still is insulated with non-corrosive glass fibre, covered by sheet metal, AISI 304 stainless steel cladding.
- The internal parts in contact with the feed water, the distillate and the pure steam, are all in mirror polished AISI 316L stainless steel as standard.
- The gaskets are in pure PTFE.
- All valves are pneumatic valves with Teflon membrane, with a body in electro polished AISI 316L stainless steel.
- The valve for inlet of feed water is in AISI 316L stainless steel.
- The framework is in satin finished AISI 304 stainless steel.
- The control system is complete with a PLC and a personal computer and printer.
- All heat exchangers are of the shell and tube type.
Producing high quality pure steam
The following technical solutions have been employed to avoid the entrainment of feed water droplets, to guarantee a consistently high quality of pure steam:
- The diameter and the height of the evaporation columns have been calculated to lower, as much as possible, the evaporation velocity of the steam.
- The level of the feed water inside the evaporation column is kept, as far as possible, far from the upper part of the column, where the liquid is separated from the gas.
- In the lower part of the distillation column, some feed water is drained automatically (discharge of the concentrate). Quantity is related to the quality of the feed water.
- The exchanger has been designed to eliminate the possibility of boiling water droplets gaining direct access to the upper part of the distillation column where the pure steam is generated.
- The heating steam flows to the DTS exchanger through a modulating valve, in this way eliminating an extremely violent boiling phase during production.
- A special labyrinth-separator is installed in the upper part of the distillation column to prevent the passage of entrained water droplets, draining all possible entrained substances that could arrive in this very important part of the generator. The separator also discharges to the lower part of the column any entrained droplets contained when the distiller stops.
- The SMEF distiller eliminates the use of induced vortex of the steam to prevent entrainment, as this can cause impingement corrosion of the exchange surfaces when droplets hit them at high speed.
Options
- A device for eliminating all condensable and incondensable gases present in the feed water.
- A device for measuring in real time the conductivity of the pure steam, provided with an alarm and stop control to halt the production of pure steam in the event of sub-standard conductivity values.
- Electropolishing of all internal parts.
- Cabinet in satin finished AISI 304 stainless steel.
- System to produce pure steam. Multistage technology also allows SMEF equipment to be utlised as a pure steam generator, for the traditional sterilisation activities in a pharmaceutical factory sterilisation of storage tanks, of solution tanks, distribution loops and more.
- A feed water booster pump set (ensuring a constant supply of feed water).
- A distillate pump set.
- A distillate cooler.
- Automatic sterilising process after prolonged shutdown.
- A computer system with printer and Windows software for plant management and statistical data recording.
