AN INDUSTRIAL TRAINING REPORT
ON

GODAVARI BIOREFINERIES LTD.
SAKARWADI

UNDER GUIDANCE OF
MR. SACHIN SASKAR

IN PARTIAL FULFILLMENT OF
BE CHEMICAL
DEGREE OF UNIVERSITY OF PUNE

DEPARTMENT OF CHEMICAL ENGINEERING
AISSMS COLLEGE OF ENGINEERING, PUNE -1
2012 – 13

SUBMITED BY

|SR.NO |NAME OF STUDENTS |
|1. |BADJATE ANIKET |
|2. |BORKAR SWAPNIL |
|3. |BHAVE VAIBHAV |
|4. |KAMBLE ROHIT |
|5. |JADHAV ABHISHEK |
|6. |DATIR SANJAY |
|7. |CHOUDHARI JIGAR |
|8. |PAWALE SATISH |

DEPARTMENT OF CHEMICAL ENGINEERING
AISSMS COLLEGE OF ENGINEERING, PUNE -1
2012 – 13

ACKNOWLEDGEMENT

We are thankful to Mr.KAJARIA SIR(Director),Mr.VASAN SIR(GMO) Mr.PALVE(AGM) and Mr.KARALE for coperating and helping us for Inplant

Industrial Training

Also We are thankful to our instructor Mr.SACHIN SASKAR for providing us their valuable guidance and encouragement in bringing out this project training successfully.

We would like to thank the previous capstone for providing required information.

We are thankful to Mr.MORE ,Mr.TEKE &Mr.WADANGALE for providing us with the resources required for our project.

We would like to thank our parents for their support.

We would finally like to thank the head of the chemical department Pr.P.N.DANGE for his guidance.

We would also like to thank all the people who helped us in this project and whom we might not have mentioned here.

INDEX

|SR.NO |TITLE |PAGE NO. |
|1. |ABSTRACT |5 |
|2. |INTRODUCTION TO ETHYL ACETATE |7 |
|3. |PROCESS |8 |
|4. |INTRODUCTON TO ACETALDEHYDE PLANT |12 |
|5. |Equipment used in Plants |18 |
|6. |Biogas Production Plant |43 |
|7. |conclusion and refrences |50 |

ABSTRACT

The Godavari Sugar Mills Ltd., incorporated in 1939, has been demerged to Godavari Biorefineries Ltd. as per High Court order dated
20.03.2009. Godavari Biorefineries Ltd. promoted by Late Shri.
Karamshibhai Jethabhai Somaiya (Padmabhushan) and his son, Dr.
Shantilal Karamshibhai Somaiya, were incorporated in 1939 & have been contributing to the industrial development of India for more than six decades. Under the dynamic leadership of the Executive Director, Shri
Samir Somaiya& his professional team, the Company with three Sugar mills is fully integrated and is among the top ten Sugar complexes out of around 500 sugar manufacturers in India. The Company is one of the largest producers of Alcohol & a pioneer in manufacture of Alcohol based Chemicals in India.
It has plants located in the states of Karnataka and Maharashtra in
India & has diverse interests in Sugar, Power, Industrial Alcohol,
Heavy Organic Chemicals, Specialty Chemicals, Bio-fertilizers &
Agricultural Research. It manufacturers more than twenty products from renewable resources, thereby forming an entire Value Chain right from
Sugar Cane to Sugar to other value added products like Power, Ethanol,
Bio-fertilizers.
The company has achieved tremendous growth acceleration in the last 10 years & has aggressive plans for the near future, as depicted below.
Godavari Biorefineries Ltd. Manufactures More than 20 Products from
Renewable.
The Company is one of the few sugar companies entirely using ERP
(SAP). It has employed modern technology in its operations, processes
& systems. The company has been internationally recognized in the past for its sugarcane yields, which were the highest in the world. The quality of its sugar is also comparable to the best and therefore fetches premium in the market. The Company has an approved
Agricultural Research Institute K. J. Somaiya Institute of Applied
Agricultural Research (KIAAR) at Sameerwadi, which works closely with other sugarcane research institutes & the farming community in developing better and newer varieties of cane. The company has two
Council of Scientific & Industrial Research (CSIR) recognized Research centers working on areas of Process technology, Product improvement,
New product development, Recovery improvement & Cost reduction.

INTRODUCTION TO ETHYL ACETATE

Ethyl acetate (systematically, ethyl ethanoate, commonly abbreviated
EtOAc or EA) is the organic compound with the formula CH3COOCH2CH3.
This colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, and cigarettes. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent.

Production
Ethyl acetate is synthesized in industry mainly via the classic
Fischer esterification reaction of ethanol and acetic acid. This mixture converts to the ester in about 65% yield at room temperature.

CH3CH2OH + CH3COOH ( CH3COOCH2CH3 + H2O

The reaction can be accelerated by PTSA (Para Toluene Sulphonic Acid) catalysis and the equilibrium can be shifted to the right by removal of water.

IUPAC Name Ethyl acetate
Systematic Name Ethyl Ethanoate
Other names Ethyl ester, acetic ester, Ester of ethanol

PROCESS

Ethyl Acetate is Prepared in Large Scale in Industry. The raw feed materials required for the preparation are Acetic Acid and Ethanol.
The Process takes place in presence of PTSA catalyst.
The main method to manufacture ethyl acetate involves the esterification of ethanol with acetic acid, although some is produced by catalytic condensation of acetaldehyde with alkoxides. The solution obtains propyl acetate as the byproduct, in the production of ethyl acetate.

In the kettle mixture of acetic acid and alcohol, reacts to form ester and a mixture of ester and water. The circulating pump is provided to the kettle, alongwith the re-boiler. The kettle is attached with vertical packed column.

The vapors of ester are passed through the packed column, which is raised vertically above the kettle.

In the condenser these vapors are cooled and are liquefied, due to which these vapors are passed to the sub-cooler for relatively more cooling.

From sub-cooler the liquefied mixture is passed to the decanter.
In decanter the separation takes place by the principle of GRAVITY SETTLING. Two layers are formed based on the difference in densities of the two liquids. The liquid of lower density, which is ester, is processed to the reflux tank. The liquid of higher density is water with a small proportion of ester.

The mixture of un-reacted alcohol and water is passed to the wash tank. In the wash tank, the water is supplied to the hot water tank and unreacted alcohol (C3 alcohol recovery) is passed to the reflux tank.

In the reflux tank, the ester is passed to the rotameter. The rotameter provides two outlets, of which one is reflux while the other is draw.

The product from the draw is passed to the wash column. In the wash column the DM water and the liquid from the rotameter is passed through the top and bottom of the wash column respectively. The two liquids (ester and water) are separated by gravity settling on the basis of density differences. From the wash column the ester is charged in C2 column while the water which contains some traces of ester, is again fed to the wash column for further separation of water.

The column C2 has three regions of which one is low boil, ethyl acetate and high boil. The ester is charged to the low boil region. There is same process as that of C1 and the main product of ethyl acetate is passed to condenser and is collected by tapping process which is stored in the storage tank. The high boils at the bottom region contains propyl acetate which is collected in C4 column which is the byproduct of the esterification process.

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Fig. Process Flow Diagram

Where the numbers indicate

1. Kettle 2.Circulatory Pump 3.Reboiler 4.Condenser

5. Sub cooler 6.Decanter 7.Washtank 8.Hotwater Tank

9. Reflux tank 10.WashColumn

a. Liquid of low density b. Liquid of High Density

C1.Reaction Column C2.Purification Column

C3.Alcohol Recovery C4.Propyl Acetate Column

Properties of ethyl acetate

1) The Molar mass of ethyl acetate is about 88.11 g mol−1

2) Ethyl acetate occurs in the form of a Colorless liquid

3) The Density of Ethyl acetate is 0.897 g/cm³

4) Melting point of ethyl acetate is −83.6 °C, 190 K

5) The Boiling point of ethyl acetate is 77.1 °C, 350 K,

6) Solubility in water is 8.3 g/100 mL (20 °C)

7) Refractive index (nD) of ethyl acetate is 1.3720

8) The Viscosity of ethyl acetate is 0.426 cP at 25 °C

Uses of ethyl acetate

1) Ethyl acetate is used primarily as a solvent and diluents, being favored because of its low cost, low toxicity, and agreeable odour.

2) Coffee beans and tea leaves are decaffeinated with this solvent

3) It is also used in paints as an activator or hardener

4) Ethyl acetate is present in confectionery, perfumes, and fruits. In perfumes, it evaporates quickly, leaving only the scent of the perfume on the skin.

5) It is used in glues, nail polish removers, and cigarettes.

INTRODUCTON TO ACETALDEHYDE PLANT

Manufacture & process

Acetaldehyde is produced by the dehydrogenation and partial oxidation of ethyl alcohol.The most used is the dehydrogenation of the alcohol. The direct oxidation being second important.The dehydrogenation process has been in commercial use since 1930. The process is particularly attractive when it is combined with other operations requiring supply’s of hydrogen because relatively pure hydrogen is formed as a byproduct of the dehydrogenation.Ethyl alcohol oxidation process is usually carried out by passing the alcohol with air or oxygen over catalyst usually metallic copper or silver compounds containing them at 300deg C to 500deg C. The water formed in the reaction may be in condensed separately.

REACTION:-

C2H5OH + ½ O2 → CH3CHO + H2O C2H5OH → CH3CHO + H2

The by-products are formed according to following reactions:

C2H5OH + O2 → CH3COOH + H2O

C2H5OH + ½ O2 → CH4 + CO + H2O

C2H5OH + 2 O2 → 2 CO2 + 3 H2O

The overall reaction is exothermic and the temperature in the reactor is 550 °C. The products are cooled instantly and the heat of reaction is used to produce steam. Further cooling is done before the products enter the absorber. The bottom stream is sent to the distillation column where acetaldehyde is removed in the top. The bottom from the distillation column is sent to an ethanol column to recover unconverted ethanol.

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The proposed process, see figure , will be using a silver catalyst and partial oxidation of ethanol. First ethanol and air is sent to a saturator and the gases leaving are saturated with ethanol. The reaction is carried out in a fixed bed reactor over a bed of silver catalyst.The stream from the reactor is sent to an absorption column where water is used to absorb acetaldehyde and the unconverted ethanol. Then a two stage distillation is performed. In the first column pure acetaldehyde is retrieved in the top and the bottoms containing ethanol, water, and acetic acid is divided. One part is sent to the mixing condenser to improve the absorption and the rest is sent to the second column where the unconverted ethanol is removed in the top and sent back to the process. The saturator acts as condenser for the ethanol column.

Occurance:

Acetaldehyde is normal intermediate product in respiration of higher plants. It occurs in traces in ripe apple and in all other ripe fruits that have fact taste before ripening. It also occurs in the gases exhaled by a ripe apples and pears. Acetaldehyde is an intermediate product of alcoholic fermentation. It is reduced to ethyl alcohol almost immediately unless the reaction is arrested as by the presence of a bisulphite. Acetaldehyde may occur in wine and other alcoholic beverages after exposure to the air imparting an unpleasant taste .ordinarily the aldehyde reacts to form acetyl ðyl acetate both of pleasant order .the ethyl acetate is acts to form acetyl ðyl acetate .the ethyl acetate is formed by way of acetic acid acetaldehyde is also intermediate product in the decomposition of sugars .in the body and therefore occurs in tresses in normal blood.

Properties of Aldehyde:
Name- Acetaldehyde
Lable- Flammable liquid class 3
Chemical Formula- CH3CHO
Boiling Point- 20.4 C
Appearance- Colourless watery
Odour- Intense pungent
Vapour density- 1.5
Specific Gravity- 0.78
Flammability- Highly flammable & explosive material
Explosive limit- LEL= 4% UEF = 57%
Flash point- OC = -50 CC = -37.7
Auto ignition temperature- 175 C
Fire extinguisher- water & CO2

Economic aspects & future prospectus:-

Since 1917 the production of acetaldehyde has been linked with the demand for cellulose acetate & since 1925 also with vinyl resin, which have been growing in importance .a number of facts to a moderate expansion of acetaldehyde production in the future. This include the importance of acetic ester &butyl alcohol as solvent ,the growing market for crotonic acid &other derivatives new research on resin with phenol &urea .the continued demand for polyvinyl acetate &polyvinyl acetyl &new applications of modifications &copolymers .

Specifications, containers &labels

Grade: -Technical

Typical specifications:-Acetaldehyde minimum 99%,colour, water-white acidity,0.5% maximum acetic acid, specific gravity 0.770 to 0.790 at 40C.

Containers:-Steel drums &tank cars

Rail road shipping regulations:-Red label.

Uses: -

Traditionally, acetaldehyde was mainly used as a precursor to acetic acid. This application has declined because acetic acid is made more efficiently from methanol by the Monsanto and Cativa processes. In terms of condensation reactions, acetaldehyde is an important precursor to pyridine derivatives, pentaerythritol, and crotonaldehyde. Urea and acetaldehyde combine to give a useful resin. Acetic anhydride reacts with acetaldehyde to give ethylidene diacetate, a precursor to vinyl acetate, which is used to produce polyvinyl acetate.

Safety Measures:-

Acetaldehyde is toxic when applied externally for prolonged periods, an irritant, and a probable carcinogen. It is an air pollutant resulting from combustion, such as automotive exhaust and tobacco smoke. It is also created by thermal degradation of polymers in the plastics processing industry. Acetaldehyde naturally breaks down in the human body but has been shown to excrete in urine of rats.

Acetaldehyde is an irritant of the skin, eyes, mucous membranes, throat and respiratory tract. Symptoms of exposure to this compound include nausea, vomiting, headache. These symptoms may not happen immediately. It has a general narcotic action and large doses can even cause death by respiratory paralysis. It may also cause drowsiness, delirium, hallucinations and loss of intelligence. Exposure may also cause severe damage to the mouth, throat and stomach; accumulation of fluid in the lungs, chronic respiratory disease, kidney and liver damage, throat irritation, dizziness, reddening and swelling of the skin.

Equipment used in Plant

Kettle reboilers

Image depicts a typical steam-heated kettle reboiler. Kettle reboilers are very simple and reliable. They may require pumping of the column bottoms liquid into the kettle, or there may be sufficient liquid to deliver the liquid into the reboiler. In this reboiler type, steam flows through the tube bundle and exits as condensate. The liquid from the bottom of the tower, commonly called the bottoms, flows through the shell side. There is a retaining wall or overflow weir separating the tube bundle from the reboiler section where the residual reboiled liquid (called the bottoms product) is withdrawn, so that the tube bundle is kept covered with liquid.

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Column

In chemical processing, a packed bed is a hollow tube, pipe, or other vessel that is filled with a packing material. The packing can be randomly filled with small objects like Raschig rings or else it can be specifically designed structured packing. Packed beds may also contain catalyst particles or adsorbents such as zeolite pellets, granular activated carbon, etc.

The purpose of a packed bed is typically to improve contact between two phases in a chemical or similar process. Packed beds can be used in a chemical reactor, a distillation process, or as scrubber, but packed beds have also been used to store heat in chemical plants. In this case, hot gases are allowed to escape through a vessel that is packed with a refractory material until the packing is hot. Air or other cool gas is then fed back to the plant through the hot bed, thereby pre-heating the air or gas feed.

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Condenser

Condenser, device for reducing a gas or vapour to a liquid. Condensers are employed in power plants to condense exhaust steam from turbines and in refrigeration plants to condense refrigerant vapours, such as ammonia and fluorinated hydrocarbons. The petroleum and chemical industries employ condensers for the condensation of hydrocarbons and other chemical vapours. In distilling operations, the device in which the vapour is transformed to a liquid state is called a condenser.

All condensers operate by removing heat from the gas or vapour; once sufficient heat is eliminated, liquefaction occurs. For some applications, all that is necessary is to pass the gas through a long tube (usually arranged in a coil or other compact shape) to permit heat to escape into the surrounding air. A heat-conductive metal, such as copper, is commonly used to transport the vapour. A condenser’s efficiency is often enhanced by attaching fins (i.e., flat sheets of conductive metal) to the tubing to accelerate heat removal. Commonly, such condensers employ fans to force air through the fins and carry the heat away. In many cases, large condensers for industrial applications use water or some other liquid in place of air to achieve heat removal.

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SubCooler

Subcooling is the process by which a saturated liquid refrigerant is cooled below the saturation temperature, forcing it to change its phase completely. The resulting fluid is called a subcooled liquid and is the convenient state in which refrigerants may undergo the remaining stages of a refrigeration cycle. Normally, a refrigeration system has a subcooling stage, allowing technicians to be certain that the quality, in which the refrigerant reaches the next step on the cycle, is the desired one. Subcooling may take place in heat exchangers and outside them. Being both similar and inverse processes, subcooling and superheating are important to determine stability and well-functioning of a refrigeration system.

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Decanter

Decantation is a process for the separation of mixtures. Usually a small amount of solution must be left in the container, and care must be taken to prevent a small amount of precipitate from flowing with the solution out of the container. It is generally used to separate a liquid from an insoluble liquid (e.g. in red wine, where the wine is decanted from the potassium bitartrate crystals). For example, to obtain a sample of clear water from muddy water, muddy water is left in a container until the mud settles, and then the clear water is poured into another container.

A mixture of two immiscible liquids can also be separated by decantation. For example, the oil and water extracted from fishes may be decanted to obtain the oil. A mixture of kerosene and water can also be separated through decantation.

A centrifuge may be useful in successfully decanting a solution. The centrifuge causes the precipitate to be forced to the bottom of the container; if the force is high enough, the precipitate may form a compact solid. Then the liquid can be more easily poured away, as the precipitate will likely remain in its compressed form. A mixture of an insoluble solid in liquid is allowed to stand. The solid being insoluble settles at the bottom if kept undisturbed for some time, this process is called sedimentation. The clear liquid is then poured off carefully, this process is called decantation.

Another example of decantation is the regeneration of used chiral stationary phase (CSP). The CSP to be decanted is gently mixed in a container with a compatible solvent to form a suspension. The suspension is allowed to rest for a period of time, after which the supernatant is carefully poured off. The supernatant contains the undesirable constituents of the former suspension, while the leftover sediment in the container is clean, reusable CSP.

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Reflux Tank

Reflux Tank that is manufactured using high grade material. These tanks are provided by us in several shapes and sizes, which is appropriate for storing liquid items properly. It is widely used in several industries for storing liquid materials; they are manufactured using supreme quality of stainless steel.
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Pump
A pump is a device used to move fluids (liquids or gases) or sometimes slurries by mechanical action. Pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps.

Pumps must have a mechanism, which operates them, and consume energy to perform mechanical work by moving the fluid. The activating mechanism is often reciprocating or rotary. Pumps may be operated in many ways, including manual operation, electricity, an engine of some type, or wind action.

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Valves

A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically pipe fit

ings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure.

The simplest, and very ancient, valve is simply a freely hinged flap which drops to obstruct fluid (gas or liquid) flow in one direction, but is pushed open by flow in the opposite direction.

Valves are majorly used in water controlling for Irrigation as well as industrial, military, commercial, residential, and transport setctors. Such as drip irrigation and sprinkler irrigation, oil and gas, power generation, mining, water reticulation, sewage and chemical manufacturing.

In daily life, most noticeable are plumbing valves, such as taps for tap water.

Valves play a vital role in industrial applications ranging from transportation of drinking water to control of ignition in a rocket engine.

Valves may be operated manually, either by a handle, lever or pedal. Valves may also be automatic, driven by changes in pressure, temperature, or flow. These changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers.

More complex control systems using valves requiring automatic control based on an external input (i.e., regulating flow through a pipe to a changing set point) require an actuator. An actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements.

[pic][pic]

fig.Butterfly Valve ig. Niddle Valve

[pic][pic]

fig.Ball Valve fig. Globe Valve

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fig. Gate Valve

Rotameter

A rotameter is a device that measures the flow rate of liquid or gas in a closed tube.

It belongs to a class of meters called variable area meters, which measure flow rate by allowing the cross-sectional area the fluid travels through to vary, causing some measurable effect.

A rotameter consists of a tapered tube, typically made of glass with a 'float', actually a shaped weight, inside that is pushed up by the drag force of the flow and pulled down by gravity.

A higher volumetric flow rate through a given area increases flow speed and drag force, so the float will be pushed upwards. However, as the inside of the rotameter is cone shaped (widens), the area around the float through which the medium flows increases, the flow speed and drag force decrease until there is mechanical equilibrium with the float's weight.

Floats are made in many different shapes, with spheres and ellipsoids being the most common. The float may be diagonally grooved and partially colored so that it rotates axially as the fluid passes. This shows if the float is stuck since it will only rotate if it is free. Readings are usually taken at the top of the widest part of the float; the center for an ellipsoid, or the top for a cylinder. Some manufacturers use a different standard.

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Pressure Gauge
Pressure gauges are used for a variety of industrial and application-specific pressure monitoring applications. Pressure gauges can be used for visual monitoring of air and gas pressure for compressors, vacuum equipment, process lines and specialty tank applications such as medical gas cylinders and fire extinguishers. In addition to visual indication, some pressure gauges are configured to provide electrical output of indicated pressure and monitoring of other variables such as temperature.
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Heat Exchanger
A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. A solid wall may separate the media, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, conditioning, power, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air.
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Boiler

A boiler or steam generator is a device used to create steam by applying heat energy to water. Although the definitions are somewhat flexible, it can be said that older steam generators were commonly termed boilers and worked at low to medium pressure (1–300 psi/0.069–20.684 bar; 6.895–2,068.427 kPa) but, at pressures above this, it is more usual to speak of a steam generator.

A boiler or steam generator is used wherever a source of steam is required. The form and size depends on the application: mobile steam engines such as steam locomotives, engines and vehicles typically use a smaller boiler that forms an integral part of the vehicle; stationary steam engines, industrial installations and power stations will usually have a larger separate steam generating facility connected to the point-of-use by piping. A notable exception is the steam-powered fireless locomotive, where separately-generated steam is transferred to a receiver (tank) on the locomotive.

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Cooling Tower

Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature.

Common applications include cooling the circulating water used in oil refineries, petrochemical and other chemical plants, thermal power stations and HVAC systems for cooling buildings.

Cooling towers vary in size from small roof-top units to very large hyperboloid structures (as in the adjacent image) that can be up to 200 meters tall and 100 meters in diameter, or rectangular structures (as in Image 3) that can be over 40 meters tall and 80 meters long. The hyperboloid cooling towers are often associated with nuclear power plants, although they are also used to some extent in some large chemical and other industrial plants. Although these large towers are very prominent, the vast majority of cooling towers are much smaller, including many units installed on or near buildings to discharge heat from air conditioning..

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Hot water Tank

Water heating is a thermodynamic process using an energy source to heat water above its initial temperature. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating. In industry, both hot water and water heated to steam have many uses.

Domestically, water is traditionally heated in vessels known as water heaters, kettles, cauldrons, pots, or coppers. These metal vessels heat a batch of water, but do not produce a continual supply of heated water at a preset temperature. Rarely, hot water will be naturally occurring, usually from natural hot springs. The temperature will vary based on the consumption rate of hot water; the water becomes cooler as flow is increased.

Appliances for providing a more-or-less constant supply of hot water are variously known as water heaters, hot water heaters, hot water tanks, boilers, heat exchangers, calorifiers, or geysers depending on whether they are heating potable or non-potable water, in domestic or industrial use, their energy source, and in which part of the world they are found. In domestic installations, potable water heated for uses other than space heating is also called domestic hot water (DHW).

In many countries the most common energy sources for heating water are fossil fuels: natural gas, liquefied petroleum gas, oil, or solid fuels. These fuels may be consumed directly or by the use of electricity (which may derive from any of the above fuels or from nuclear or renewable sources). Alternative energy such as solar energy, heat pumps, hot water heat recycling, and geothermal heating, may also be used as available, usually in combination with backup systems supplied by gas, oil or electricity.

In some countries district heating is a major source of water heating in densely populated urban areas. This is especially the case in Scandinavia. District heating systems make it possible to supply all of the energy for water heating as well as space heating from waste heat from industries, power plants, incinerators, geothermal heating, and central solar heating. The actual heating of the tap water is performed in heat exchangers at the consumers' premises. Generally the consumer has no in-building backup system, due to the very high-expected availability of district heating systems.

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Demineralised Water

Demineralised water is water completely free (or almost) of dissolved minerals as a result of one of the following processes: • Distillation • deionization • Membrane filtration (reverse osmosis or Nano filtration) • electrodyalisis • Or other technologies.
The amount of dissolved solids in water that has followed one of these processes could be as low as 1 mg/l and is in any case always less than 10 mg/l. The electrical conductivity is generally less than 2 mS/m and may be even lower (< 0,1mS/cm).
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Sand Bed Filter
A sand bed filter is a kind of depth filter. Broadly, there are two types of filter for separating particulate solids from fluids:

▪ Surface filters, where particulates are captured on a permeable surface ▪ Depth filters, where particulates are captured within a porous body of material.
In addition, there are passive and active devices for causing solid-liquid separation such as settling tanks, self-cleaning screen filters, hydro cyclones and centrifuges.

There are several kinds of depth filter, some employing fibrous material and others employing granular materials. Sand bed filters are an example of a granular loose media depth filter. They are usually used to separate small amounts (