Fundamental Concepts Of Food Industry Drying Process Custom Standard

Fundamental Concepts of Food Industry Drying Process

Various processing methods are there for preservation of food processing units like Freezing, canning, preserving in syrup, food irradiation, salting, vacuum packaging, dehydration or drying.

Drying means removal of a liquid from a liquid/ semi-solid/ solid to produce solid product by thermal energy input causing phase change. Sometimes converts solid moisture into vapor by sublimation process. For example freeze drying with application of heat.

The process of drying needed for the purposes of storage and preservation, reduction in cost of transportation etc.

Drying is a complex Thermal process. Drying occurs by supplying heat to the wet feedstock in the form of effecting vaporization of the liquid.

Energy input may be supplied by the following

Conduction (contact or indirect dryers)

Convection (direct dryers)

Radiation (Placing the wet material in radio frequency electromagnetic field or in a microwave)

Microwave and Radio Frequency Fields

Combination of above methods

Moisture output comes out by the following ways

Vapor diffusion.

Liquid diffusion

Surface diffusion

Capillary flow (Permeability)

Poiseuille flow

Combination of above

Most of the dryers are of the convection type with direct combustion gases or hot air as the drying medium because water is the most common solvent removed in dryers

Direct Dryers (Convective): Drying medium directly contacts material to be dried and carries evaporated moisture.

Indirect dryers (Contact or conduction)

Initial period

In this first phase sensible heat is transferred to the product and the contained moisture. During this period mostly free moisture being removed with the rate of evaporation increases dramatically .

Constant rate period

In this second phase when the free moisture continue to exist on the surfaces and the rate of evaporation alters very little as the moisture content reduces. During this period, evaporation proceeds at a constant rate.

Falling rate period

In the third phase migration of moisture from the inner interstices of each particle to the outer surface becomes the limiting factor that reduces the drying rate. The film of moisture becomes exhausted and evaporation slows due to reduced surface area.

Hengyang Industry is an Chinese Company based in Zhengzhou city that manufactures, on proprietary technology, plants and equipment for waste recycling and recovery with energy production, material recovery or production of finished goods.

Innovation, R&D, passionate and skilled team along with the customer satisfaction have always been the success of Hengyang and they still are the peculiarities of our Company. Besides the historical Hengyang equipment, like single and double shafts shredders, Crushing machine, briquetting machines, separators, squeezers and centrifuges, the Company offers a wide range of turn-key plants, among which:

• briquetting and pelletizing plants
• shredding plants
• Waste Sorting Plants
• Bio-fuel Plants
• Waste to Power Recycling Plants
• Mining Plants
• OEM Equipments
……..
Hengyang is able to develop customized solutions too.
Designed, constructed and assembled by the same Hengyang

The Company policy focuses on product quality: robustness and functionality of the machines that maintain their value over time.
The ability to challenge ideas and concepts and to interact with partners worldwide has allowed and still allows Hengyang to stay highly competitive and to be an ideal partner for the world market.