Ralli Oy (Ltd.)
Evaporator (Falling Film / Rising Film)
Product Description
FALLING FILM EVAPORATORS:
Removal of excess water and thereby concentrating useful solids available in any liquid product is a necessity in many process industries such as Dairy, Fruit Juices, Starch, Malt, Sugar, Chemicals, Paper and Pulp and other similar industries.
OPERATION
In falling film evaporators the product to be concentrated is introduced into the top part of the evaporator. A distribution plate distributes the product evenly on the surface of heated tubes, creating a down flowing thin film. As the product flows downwards at boiling temperature, evaporation takes place thus removing liquid and concentrating the product.
The solution boils at low temperatures because of the vacuum inside the evaporator. Due to the low boiling temperatures, ranging from as low as 40 deg. C to 70 deg. C, and short product contact times, these properties make falling film evaporationtechnology suitable for handling of heat-sensitive products. The falling film evaporators are the most used ones in the food industry.
OPERATION
In falling film evaporators the product to be concentrated is introduced into the top part of the evaporator. A distribution plate distributes the product evenly on the surface of heated tubes, creating a down flowing thin film. As the product flows downwards at boiling temperature, evaporation takes place thus removing liquid and concentrating the product.
The solution boils at low temperatures because of the vacuum inside the evaporator. Due to the low boiling temperatures, ranging from as low as 40 deg. C to 70 deg. C, and short product contact times, these properties make falling film evaporationtechnology suitable for handling of heat-sensitive products. The falling film evaporators are the most used ones in the food industry.
MULTI-EFFECT
Two of more effects can be combined in order to create a multi stage evaporator, ormultiple-effect evaporator. The vapors from the preceding stage are used as the heating media of the next stage, thus improving the overall efficiency. Each stage operates at a lower pressure and temperature than the preceding stage, in order to maintain the temperature difference. The energy of the vapor can be added by thermal vapor recompression or mechanical vapor recompression.
Because multi-stage falling film evaporators extract water from the products at extremely low energy consumption, this and the above mentioned properties make this technology suitable in commercial applications. Ralli Oy (Ltd.) specializes in the design, fabrication, supply and commissioning of multi-stage falling film evaporators. A team of experts make thorough studies in close association with the clients, resulting in an optimum design in terms of capacity and layout.
Because multi-stage falling film evaporators extract water from the products at extremely low energy consumption, this and the above mentioned properties make this technology suitable in commercial applications. Ralli Oy (Ltd.) specializes in the design, fabrication, supply and commissioning of multi-stage falling film evaporators. A team of experts make thorough studies in close association with the clients, resulting in an optimum design in terms of capacity and layout.
THERMAL VAPOUR RECOMPRESSION (TVR)
TVR system is mostly adopted either for high boiling point elevation products or in countries with high electricity costs. TVR is used to give better efficiency by means of steam ejector. In steam ejector motive steam speed is increased around 1000m/s thus making vacuum and picking up vapor from separator. The vapor extracted from one stage is used, if necessary after recompression, as the heating medium for the next state at a lower temperature and pressure to improve evaporator efficiency. Number of stages is limited by overall temperature difference of system or investments costs against running costs. Temperatures are mainly determined by the heat sensitivity and viscosity of the product.
MECHANICAL VAPOR RECOMPRESSION (MVR)
TVR system is mostly adopted either for high boiling point elevation products or in countries with high electricity costs. TVR is used to give better efficiency by means of steam ejector. In steam ejector motive steam speed is increased around 1000m/s thus making vacuum and picking up vapor from separator. The vapor extracted from one stage is used, if necessary after recompression, as the heating medium for the next state at a lower temperature and pressure to improve evaporator efficiency. Number of stages is limited by overall temperature difference of system or investments costs against running costs. Temperatures are mainly determined by the heat sensitivity and viscosity of the product.
MECHANICAL VAPOR RECOMPRESSION (MVR)
MVR is superior both in running economy and gentle handling of the product. Minimum energy consumption with maximum concentration is the base for MVR technology. Very low single boiling temperature and low temperature difference can be achieved and therefore the heat load to product is absolutely minimum. MVR compressor or high pressure fan run by motor, compresses vapor sucked from separator to higher pressure, thus increasing vapor temperature and enthalpy. This vapor is fed outside of tubes and is used as heating medium for evaporation in the next stage.
We at RALLI OY (Ltd.) are experts of several kinds of evaporation technologies, including multi-staged falling film evaporators, using thermal vapor recompression (TVR) or mechanical vapor recompression (MVR). We have more than 20 years of expertise in designing, commissioning and refurbishing evaporation systems. If you have a need for a new or used evaporator or want to increase the capacity of your existing evaporation solution, contact us. Our team of experts will find the best suitable solution for you.
RISING FILM EVAPORATORS:
OPERATION
In rising film evaporators the product is introduced into the evaporator from the bottom. As the product enters the bottom of the heating tubes, it begins to boil, creating vapor. The pressure of the vapor causes the product to start rising as a thin film, pressing it against the heating tubes. As the product rises at boiling point, more evaporation takes place. The product may be recycled in order to achieve the desired concentration.
The highly turbulent flow of the rising product is beneficial in the evaporation of highly viscous products or products that have a fouling tendency.
In order for the vapor flow to have enough energy to start rising the product, the temperature difference between the heating side and the boiling needs to be high. Otherwise the rising film is not created.
We at RALLI OY (Ltd.) are experts of several kinds of evaporation technologies, including multi-staged rising film evaporators, using thermal vapor recompression (TVR) or mechanical vapor recompression (MVR). We have more than 20 years of expertise in designing, commissioning and refurbishing evaporation systems. If you have a need for a new or used evaporator or want to increase the capacity of your existing evaporation solution, contact us. Our team of experts will find the best suitable solution for you.
Company Profile:
RALLI OY (Ltd.) was founded by Mr. Seppo Ralli, a Mechanical Engineer, in the year 1985. The company was established as Consultancy Company for the Designing of Evaporation and Drying systems for Dairy / Food / Starch and Biotechnology related Industries. In order to strengthen the operations in Asia, especially in India, RALLI OY (Ltd.) started to cooperate with an Indian based company FOOD & BIOTECH ENGINEERS, a company specialized into fabrication and design of Food and Biotechnology related processes and equipment.
Within a short span the company had Designed, Manufactured and Commissioned more than 100 projects in various fields of Dairy, Starch, Food and Biotechnology to the entire satisfaction of our customers worldwide.
The Company is headed by Mr. Seppo Ralli who is a Mechanical Engineer specialized into Food, Dairy and Biotechnology related processes and equipment. In India technical aspects are being looked after, under Mr. Seppo Ralli’s guidance, by Mr. R.P. Singh, B.Sc (Dairy Technology), M.Sc (Dairy Engineering) and Mr. D.K. Dhawan, a Management Graduate. The technical team of RALLI OY (Ltd.) consists of expert engineers from respective fields of Dairy, Starch, Food and Biotechnology industries.
RALLI OY & its associate company FOOD & BIOTECH, specializes in:
-Designing and manufacturing of Evaporation and Drying Plants.
-Installing and Commissioning of Plants.
-Formulation in Processing / Production for Various Starch Derivatives, Milk, Food & Fruit Juices.
-Economization in energy consumption by selecting efficient Evaporators/Drying Technology.
-Assistance in Modernization to optimize process parameters resulting in process cost reduction
-Serving the Dairy, Starch, Food Processing, and Biotech & Chemical industries with capabilities providing design services, equipment supply, modular process skids, fabricated components and system integration.
RALLI OY offers a full range of manufacturing of Process Plants / Vessels / Heat Exchangers / Evaporators / Dryers / Mixers etc. depending upon the customer’s requirements. RALLI OY, serving the needs of clients worldwide, has very competitive pricing in combination with high quality.
