Disinfection of Drinking water - Evoporation Technologies

Evaporators Types and Design

Evaporation is an operation used to remove a liquid from a solution, suspension, or emulsion by boiling off some of the liquid. It is thus a thermal separation, or thermal concentration, process. The evaporation process is one that starts with a liquid product and ends up with a more concentrated, but still liquid and still pump-able concentrate as the main product from the process. During the design of evaporation plants Legal regulations, materials of construction and surface finishes,product's heat sensitivity, viscosity and flow properties, foaming tendency, fouling and precipitation, boiling behavior,costs for operation and maintenance,operating media,Site conditions etc., have to be considered.There are different evaporator types like Electrically heated, circulating hot water vapouriser.

ELECTRICALLY HEATED EVAPORATORS CAPACITIES UPTO 200 Kg/hr E-205

For Chlorine, also used for Sulfur Dioxide or Ammonia

GENERAL Electrically heated evaporators are used to convert liquid chlorine as specified into gaseous state. The unit has adequate controls and safety functions.

Chlorine is available in liquid form but is generally utilized as a gas. Chlorine gas is normally withdrawn directly from containers when withdrawal rates do not exceed the container vaporization rate. If a large quantity of chlorine gas is required, Chlorine evaporators are used.

OPERATING PRINCIPLE

Liquid chlorine is transferred from its source to the evaporator chamber by container pressure.

This chamber is immersed in a controlled heated water bath, which increases the temperature of the liquid, causing it to boil. Liquid enters the chamber and maintains the required liquid level necessary to meet the vaporization rate for the gas demand. A change in gas demand will cause the chlorine liquid level to adjust. The gas released, rises through baffles and superheated as it leaves the chamber. A superheated gas is required to prevent gas reliquefaction in process piping.

INSTALLATION

Location

The evaporator should be located close to the source if possible. The length of liquid and gas lines should be kept to a minimum. Container room with provisions for exhausting gas, if a leak develops, is ideal. A lifting device above the evaporator is recommended for servicing the chamber.

CATHODIC PROTECTION

The water wetted surfaces of the evaporator are protected against corrosion by two sacrificial anodes. The anodes being the most active metal in the evaporator will suffer corrosion and supply the electrical current needed to protect the structure.

SAFE & SELF ADJUSTABLE CAPACITY

Evaporator cannot fill with liquid to build excessive pressure because its liquid level is self-adjusting. An automatic shut-off and pressure reducing valve is included. A water temperature control thermostat and contacts for low water temperature alarm are also included. Other devices, as optional are high water temperature alarm switch; a gas temperature gauge on the instrument panel; and a low water alarm actuated by a level probe.

Because the evaporation rate is self-adjusting, the proper liquid level is always maintained in the gas chamber. The proper water bath level is maintained by a make-up-water flow meter with a manual control valve. Or, an automatic make-up-water level system is optional, Level probes in this resistance-type system open and close a solenoid valve to maintain the proper water-bath level.

RELIABLE OPERATION FULLY AUTOMATIC

This is a water immersed-tank heat exchanger specifically designed to evaporate liquid chlorine. Sulfur dioxide of ammonia. Heat from a hot water bath converts liquid to gas. immersion type electric heaters supply the heat.

The evaporator is designed for safety. It requires minimum maintenance. With several options, operation can be fully automatic.

Power Characteristics: 400-440 V. 3 phase, 50/60Hz

• Dimensions: Dimension drawing numbers same as model numbers with prefix "DM".

• Installation: Installation drawing numbers same as model numbers with prefix "IN".

Materials of construction

• Cabinet : Fiberglass reinforced

• Water chamber: Steel

• Vapourizing chamber: Steel

Accessories

Automatic water level control

Immersion heater contractor

Liquid lines

Gas lines

Gas pressure reducing and shut-off valve

Cathodic protection in water chamber

Electric control panel

Ordering information

Model number

Medium to be vapourized

Capacity (kg/h)

Accessories-required and optional

Installation and service

Specialized technicians are prepared to install and service this and associated equipment.

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