Milk powder production

Production Process

On arrival at the center, the milk is tested for hygiene and adulteration using organoleptic and lactometer readings. Milk is weighed using graduated aluminum milk gauges and a volume-based payment is made to suppliers. Then the collected milk will be transported to the plant. This process is designed for both the reception of milk in cans as well as in road tankers. After reception, the milk is filtered and cooled. The production process involved with milk powder plant is discussed as follows. After reception of the milk, it is filtered and cooled down to 6 Celsius and stored in a raw milk storage tank. The milk, transported to the plant by means of road tankers is additionally pulled through a degasser to remove air from the milk. From the storage tank the milk is transferred to the first section of a pasteurizer, to give the product the required temperature for standardizing and clarifying.

The standardized milk is now returned to the pasteurizer for pasteurization and recoiling. The product cooled to 6 Celsius is then stored in storage silos. Some vitamins are added where sugar can be added to the silos on request. The silos are provided with high energy mixers to ensure that the sugar will be completely dissolved. By a transfer pump the standardized milk is then fed through pre heaters, a regeneration section and a pasteurizer to the first effect of a four-effect falling film evaporator. In this section the milk is concentrated to 47% total solid or, when sugar is added, to about 52.5% total solid. The concentrate is then filtered and by a high pressure pump transferred to the atomizer nozzles of the spray dryer. The concentrate is atomized into hot drying air. The hot air evaporates the water contained in the atomized concentrate. The milk powder leaves the spray dryer to a two stage fluid bed drying and cooling unit for the final drying. Between the two stages of the drying and cooling unit a lecithin dosing system is provided. The lecithin gives the milk powder the instant quality. From the dryer and cooler the milk powder is conveyed to a packaging section. The milk powder is then packed by a volumetric-type filling machine into cans.

The alternative technology is designed to reduce the loss of the output emanating from high heat treatment of the milk and the subsequent evaporation.

Maize starch production process flow chart

Maize is cleaned and transported in to steeping vats. The steeping water has a temperature of maximum 52⁰C which is maintained by circulation via a heat–exchanger. To facilitate the gluten separation about 0.2 to 0.3% sulfurous acid is added. This additive also bleaches the starch. The steeped maize is discharged by screw conveyors to the de-germinating mill. It breaks up the maize kernels and sets the germs free without damaging them. 

 Flow sheet of maize starch manufacturing process

The maize slurry drops into the germ separator where the fat-containing germs are separated from the slurry and flow into a container. They are pumped into a washing machine and a dewatering press. The germs are then dried and ready for storage. Having high value edible oil content of about 45%, the germs can be used for oil extraction. The maize slurry flows into the container and is pumped to the refiner mill. For coarse fiber washing, the slurry is delivered to an extraction section. The starch milk is collected in raw milk vessels equipped with stirrers. The crude starch milk is pumped to the extraction section for fine fiber washing. From the extractors the starch milk flows to the container. This is followed by a series of filtering and refining processes which results in high quality maize starch. By-products of the process include high quality animal feed. 

By using an alternative technology, maize starch can be made using a larger scale and capital intensive technology. As compared to the technology used to produce maize starch at a smaller scale, this technology is expensive but requires less labor per unit of output.

Laundry soap manufacturing

Production Process

Laundry soap production regarding to this project is batch system. Soap making or the saponification process is done by reacting fatty acids with a caustic alkali, the properties of the resulting soap depending on the mixture of fats used, the kind of caustic alkali and the actual process employed. Caustic soda is most often used but caustic potash, or a mixture of the two, are also suitable. Potash produces a finer product. Sophisticated items such as perfumed bath preparations require prior bleaching and deodorization of the fats to achieve the color, odor and performance features desired in the finished bar.

i) Oil slowly heated in an open pan; concentrated caustic soda solution added, slowly in small quantities at a time, boiling over a period of several hours. The mixture must be boiled under controlled conditions, to ensure completion of the saponification process without over-boiling.

ii) A moderate heat is maintained and each addition of caustic soda solution is allowed to react fully with the oils, before the next addition. Hasty addition of caustic soda solution will result in undesirable graining. If the mass shows signs of separating or graining, further water is added to bring the oil charge to a homogeneous state.

iii) After as much as 5 hours boiling, a fatty layer emerges on top of the mixture. This is mostly half-spent caustic, some of which should be added to the next batch in the pan to speed emulsification. Eventually the soap separates as a loose curd leaving more ½ spent caustic. The mass thickens, gets increasingly transparent and finally assumes a peculiar shiny translucent surface free from froth. If colors are to be added to the soap these should be incorporated before closing the boiling operation.

iv) On settling and cooling, which may take up to 4 days, the soap separates into 3 layers, pure neat soap uppermost, next an impure nigre soap and at the bottom a nigre lye. The pure soap is skimmed off for further processing the nigre soap goes to be re-worked and the lye gets returned to a next boiling batch. Perfumes, if any, may be added after the soap charge in the pan has become cooled a little.

v) Builders and fillers are added and thoroughly crunched in; the soap is then transferred to frames for subsequent cooling and cutting.

A valuable by-product of this process is glycerin, which is usually recovered by chemical treatment, followed by evaporation and refining. (Refined glycerin is an important industrial material used in foods, cosmetics, drugs and many other products.)

If the producer requires alternative technology one can employ Semi-Boiled or Cold processes which are economical and simple ways of making soft or potash soaps, requiring low-cost investment in equipment and no sophisticated skills. In addition to the above two alternatives, continuous processes with automated and compact equipment are widely employed to save installation space, consumption of steam and electric power and labor.

Insecticide Aerosol

Production Process

The production process to be employed in the envisaged plant involves the preparation of the insecticide spray and bottling (can filling).

The insecticide raw material is blended with synergist and other ingredients such as aromatic essence to a given formulation. The blend is then filtered to remove any impurities. Alternatively, ready blended aerosol concentrate can be bought in and diluted. The can should be inspected on receipt and later air blast cleaned before the filling operation.

The product filler and crimper/gaster and mounted on an operating bench which has an integral extraction system. At this level of production, the cans are fed manually into the enclosures of both machines. It is also possible to employ automatic enclosure systems, which produce 12-15 cans a minute. The insecticide solution is pumped from the storage tank to the filling machine where the cans are filled. They are then passed to the crimper/gaster where they are filled with the propellant and sealed tight by fitting an inner stopper and cap.

The propellant is filtered before being pumped into the filler machine fitted with gas detection equipment. Finally the caps are mounted on the cans which are then packed in carton boxes for dispatch after inspection.

Fruit based drinks

The fruit is fed into the brush washing machine. The remaining impurities are then removed by an air-injection washing machine. It then passes to the sorting line where damaged fruit is eliminated. The citrus fruit is transported to the fruit extraction device, which is connected to the oil separating device and the oil expeller device. Whole fruits are sorted according to size. After sorting according to size, the fruit passes in groups into the juice maker. From there the juice is delivered by pump to the clarification device where solid impurities are removed. Mixed with syrup, the purified fruit juice is pumped to the homogenizer. It passes through a preheated, an aerator and a condenser and is delivered to the homogenizer by screw pump. The homogenizer makes the micro-structure of the juice more homogeneous and improves its quality. 

 
The juice is then delivered to the pasteurizer and pumped in. It is sterilized by being kept for a period at the proper temperature. On leaving the pasteurizer, the juice passes either to the juice store or to the filling and bottling section. The filling machine fills the juice into bottles, jars or plastic containers.

Alternatively, fruit based drinks can be made using a cheaper production methods which require a high proportion of manual work. However, it is not advisable to prepare fruit based drinks by such method due to the problems that are related with quality control.

Essential oils production

Production Process

The most appropriate production process of essential oil production from the leaves of eucalyptus globulus plant is steam distillation.

Generally speaking steam distillation is the most common method of extracting essential oils. First, fresh or sometimes dried, botanical material is placed in the plant chamber of the still and pressurized steam is generated in a separate chamber and circulated through the plant material. The heat of the steam forces the tiny intercellular pockets that hold the essential oils to open and release them. The temperature of the steam must be high enough to open the pouches, yet not so high that it destroys the plants or burns the essential oils. As they are released, the tiny droplets of essential oil evaporate and, together with the steam molecules, travel through a tube into the still's condensation chamber. As the steam cools, it condenses into water. The essential oil forms a film on the surface of the water. To separate the essential oil from the water, the film is then decanted or skimmed off the top. The remaining water, a byproduct of distillation, is called floral water, distillate, or hydrosol.

There are alternative ways of producing essential oils. These are Cold Pressing or Cold Compression (which is mainly used to obtain citrus fruit oils), and Solvent Extraction (a method of extraction used on delicate plants). However, for the eucalyptus globulus, steam distillation is more appropriate. 

Production of Paper from straw

The basic process of making paper from straw involves two stages: The first stage is the breaking up of wheat straw in water to form a pulp (i.e. a suspension of fibers). In this stage the wheat straw is first cut and then cooked. This is followed by some form of treatment, such as beating and refining, to enhance the quality of the final product. Before paper making is conducted, stock and chemical preparation is made. The second stage represents the formation of sheet paper. This involves formation of sheet in the mould, pressing and drying often under pressure. Finally paper is cut into the required size by the cutter machine.

The alternative production technology makes use of a process that involves the use of manual labor in the washing, pulping and the formation of sheet in the mould. Although this approach requires lower investment, it is used in a less standard and low volume production and hence is not suitable for the quality product proposed by the envisaged plant.

Citric acid production process

Citric acid can be extracted from the juice of citrus fruits, by fermentation of glucose with the aid of the mold Aspergillus niger and synthetically from acetone or glycerol. 

 

Today, essentially all of the commercial citric acid is produced by fermentation. Processes employed are surface or submerged fermentation by mold (Aspergillus niger) and submerged fermentation by yeast

Carbondioxide production process

Coke is burned under specially designed boilers in carborundum lined furnace.  Combustion is controlled by drafts, so that flue gases contain 17-18% carbon dioxide.  At the same time steam is generated in the boilers to furnish power for the pumps and compressors and heat for the lye boiler.  The hot flue gases, containing oxygen, carbon monoxide, nitrogen, dust and some sulphur and organic compounds, in addition to 18% carbon dioxide are passed through a heat exchanger and economizer.  Here the temperature of the gases is reduced and the excess heat is taken up by the counter currently flowing strong lye.  The gases are scrubbed in limestone packed towers with water from the coolers to remove sulphur dioxide and dust and to reduce the temperature to about 38^oC.  The dilute carbon dioxide is then fed into the bottom of the coke filled absorption towers where it passes counter current to an aqueous solution of sodium carbonate called weak lye.  After absorbing the carbon dioxide, the solution of bicarbonate, known as strong lye, is pumped through heat exchangers, where the solution is heated before entry into the lye boiler.  The absorbers remove all but about 9% of the carbon dioxide in flue gas, which is then released to the atmosphere.

The preheated solution of sodium bicarbonate is heated with exhaust steam (from the compressors) in the lye boilers.  Here, at a temperature of about 118^oC, the bicarbonate is decomposed into sodium carbonate (weak lye), which is returned through heat exchanger to the absorbers for reuse.  The liberated gas, consisting of 99.8% carbon dioxide, escapes through the rectifying section of the lye boiler, where it warms the entering strong lye solution.  The gas pass through a water cooler, where the temperature is further lowered and the moisture in the saturated gas is condensed and returned to the weak lye.  The cooled gas is collected in a gas holder.  In place of sodium carbonate, other absorbents, such as aqueous potassium carbonate, mono ethanolamine (10 to 20%) and triethanolamine may be used.

Before or during liquefaction, the concentrated gas is purified by removal of organic impurities that would affect its taste and odour, and the gas is dried.  Various methods or so-called cycles of liquefaction are employed, such as pre-cooling, binary, ternary, bleeder, or flash cooling cycles.  These operate on the raw gas or on a combination of raw and revert gases using two or three stage compression and ammonia refrigeration, carbon dioxide flash cooling, or a combination of both.

In the ternary cycle, the carbon dioxide from the gas holder is cooled to 4^oC and raised to a pressure of 75 psi absolute in the first stage of the primary compressor.  The compressors, usually two sets, are driven by the live steam from the boiler and the exhaust steam from them is used in the lye boiler.

From the first stage, the gas is passed through a purification system consisting of an oil separator and a scrubber, containing potassium permanganate solution or potassium dichromate solution, which oxidizes organic impurities.  The gas from the scrubbers, raised in temperature to about 10^oC, enters the second compression stage and is discharged at a pressure of about 350 psi absolute.  The temperature is lowered by water coolers to 4^oC, at which point some of the water and vaporized lubricating oils (such as glycerin) are condensed.  The gas passes through a desiccant drying tower (calcium chloride), where sufficient water is removed to prevent freezing of the valves.  The gas is compressed to 970 psi absolute in the third stage, passed through a cooler, and liquefied in a condenser at 26.7^oC (critical temperature is 31.35^oC).  Non-condensable gas is purged, and the 99.9% liquid carbon dioxide, containing less than 0.1% moisture and free from organic impurities, is either fed to flash coolers or charged into cylinders.

All the materials to be used in the production of CO₂ are environmentally friendly and the combustion products are parts of the atmosphere and do not need any treatment before releasing.

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CALCIUM SILICATE

Process Description

           

 The main raw materials used for manufacturing calcium silicate are lime, hydrochloric acid and sodium silicate.
Burnt lime is treated with hydrochloric acid to produce calcium chloride.  The addition of acid should be so calculated and adjusted that almost a neutral solution is obtained.  The clear solution of calcium chloride is decanted from the top.  A portion of calcium chloride is taken in evaporators and crystallized in suitable crystallizers.  The remaining part of calcium chloride solution is then treated with a clear sodium silicate, when calcium silicate is precipitated out.  The precipitate is centrifuged, washed, dried and packed in suitable containers.

The washed out solution of Calcium silicate production can cause to contaminate surface and ground waters, and land.  To make the manufacturing process environment friendly it is necessary to have a waste disposal and treatment basin. 

Major equipments

Evaporator  

Crystallizers

Tray drier 

Pulverizer 

Furnace