Module 1. Dairy Development in India
Module 2. Engineering, thermal and chemical proper...
Module 3. Unit operation of various dairy and food...
Module 4. Working principles of equipment for rece...
Module 5. Dairy plant design and layout, compositi...
Module 6. Deterioration in products and their cont...
Module 7. Physical, chemical and biological method...
Module 8. Changes undergone by the food components...
Module 9. Plant utilities requirement.
Lesson 15. Dairy plant design and layout-I
In the dairy plants, there are number of unit operations being carried out to convert raw milk into value added finished products. They employ all sorts of resources like raw materials, plant utilities (water, air, electricity, refrigeration, steam and waste treatment etc.), plant-machinery and human resource. All these resources are accommodated in one or more buildings located in campus in order to boost the economy of interactions between these housings and various resources. Thus, a good planning is required to help smooth flow of resources for effective operations that provide hygienic atmosphere during production in one hand and economy of operations and value addition on the other.
In India, the organized dairy sector processes less than 15% of total milk production whereas the rest is either consumed at home or used in unorganized sectors like sweet makers. Especially during lean period the capacity utilization of the plant goes down hence milk remains underutilized. Operation of unnecessary large size plants and equipment becomes uneconomical due to more operational expenses along with other overhead expenses. Thus, illogically designed dairy plants fetch higher investment and working capital. Hence, various factors that are relevant to design and layout of dairy plant must be looked into.
15.1 Classification of dairy plant
Looking to the unit operations and product profile, dairy plants could be categorized as liquid milk processing plants, products manufacturing plants or combination of these two (i.e. Composite Dairy Plants).
15.1.1 Liquid milk Processing Plant:
In such plant raw milk is received at the dock, chilled, processed (pasteurized) and packed for sale. These plants directly procure milk from recognized milk sheds or other sources. Such plants have little value addition but with high liquidity of money, as the payment for raw milk is done after 7 or 10 days, whereas realization is either in advance or on the same day. Furthermore, the realization money is circulated on daily basis creating an advantage for low requirement of working capital.
15.1.2 Product Manufacturing Dairy Plants:
Raw milk is converted into value added milk and milk products by engaging suitable technologies and using proper equipment. Manufacture of these products improves the viability of the overall milk business. Other benefit lies in the conversion of perishable milk into products with long shelf life, which are suitable for distant marketing.
15.1.3 Composite Dairy Plant:
Most of the dairy plants do have facilities for processing and packaging of milk and milk products. This benefits the dairy plant in terms of high liquidity of cash together with the advantage of better shelf life and value added products. Such milk plants are more viable and sustainable.
15.2 Planning considerations for dairy plant
Planning for dairy plant should consider following aspects:
a) Projecting of milk business with respect to milk procurement and marketing;
b) Market research for product demand;
c) Accessibility & requirement of land, topography to suit disposal of waste and communication;
d) Investigation of water requirement and availability; and
e) Permissions from municipal, pollution and aviation authorities.
Based upon above factors, taking into full consideration the selection of plant location, design and layout, dairy plant of desired capacity could be designed.
15.3 Site location
The main criterion of functional importance is the minimum cost for procurement, production and distribution. Other vital factors which should favour, the location include topography, shape and size of site, availability of water, power/ fuel and climatic conditions. Yet, due to increased pollution and industrialization, all sites are not permitted for industrial work. Some incentives are being provided by some states or central government for development of certain industries on specified locations, that also requires to be looked into. These are some of the points that need to be analyzed thoughtfully for finding out the best location.
15.4 Estimation of capacity
Selection of facilities and equipment for optimum handling of the various resources involved in the manufacturing of products are the key factors for successful design. Hence, the first step would be the estimation of the capacity of a dairy and earmark production of various products with capacity. Other requirements like equipment, utilities, structure and manpower can be estimated accordingly. Generally following main factors are taken into consideration:
a) Milk shed area and its potentiality,
b) Future probability of expansion,
c) Nearby dairy plant, its distance and expansion possibilities,
d) Connectivity of villages, possibilities for milk procurement and expected development,
e) Productivity of animals and future aspects affecting milk production,
f) Allied occupation of farmers and extent of their sustainability,
g) Social tendencies for milk business,
h) Government policies for boosting milk production,
i) Change in life style, purchasing power of consumers and nutritional awareness among people.
15.5 Selection of plant equipment
Some of the important points for deciding equipment are detailed below:
a) Select the production technology,
b) Calculate the number of equipment required, with their capacities,
c) Finalize the production line according to the multiple uses of processes and requirement of products having provision to get maximum benefits. Some plants have process sequence, whereas others are specific to products.
d) Study the cleaning and sanitary provision to allow maintenance, cleaning, disinfection, monitoring and inspection.
e) The construction material should be non-reactive, non-toxic, non-corrosive and of food grade quality especially that coming in direct contact with the milk. It should be able to withstand processes like heating and cooling. Materials for heat exchanger should be good heat conductors.
f) Wherever necessary, equipment should have provision for controlling and monitoring of temperatures, humidity, airflow and other parameters which else would be considered as harmful to food safety.
g) Space requirement for equipment should be calculated.
h) Utility requirements associated with the product and equipment.
i) Spacing between adjacent equipment and service pipelines to facilitate maintenance.
j) Develop flow diagram for identification of operation sequence and material flow.
k) Consider the housing requirement for each product and equipment. Some products need to be manufactured in controlled atmosphere and need proper building, whereas others manufactured within the equipment kept in open. Similarly some of the equipment requires proper housing and others need open air for their efficient operation.
In dairy industry there are lots of examples to witness the above situations. For examples, ammonia condenser used in the refrigeration plant needs to be kept in open for maximum dissipation of heat, whereas milk vats need to be placed in the sanitary place with complete enclosure. While visiting a dairy plant one can have notice of such aspects.
a) Find out economy of material handling by using natural or gravity flow.
b) Find out operation economy by proper location of section or equipment. In other words, we should not place openings of low temperature or cold room directly facing to west if frequent openings are to be in the second half of the day. Similarly, openings or doors of high hygiene production area should not open towards the unhygienic area, without safety measure like air curtain or anti-room.
After giving full considerations to above aspects, next planning step would be to design establishment for production and other facilities, which is detailed in the next lecture.