The use of mechanical separation equipment is critical in many of the operations of the food and beverage production sector: partly to assure the required quality in a liquid product, whether this be a thick mayonnaise or a crystal clear drink; partly to keep harmful contaminants out of the materials in process, and especially out of the sector’s products; and increasingly in the recycling of wastes.
There is a very wide range of manufacturing steps involving liquids in the food and beverage sector, some with quite high intrinsic values, offering scope for a wide range of filtration processes. There is less opportunity for the use of gas filtration in the processing stages, although considerable need for the use of gas treatment in its protective functions. Almost all the main processing tasks for filtration in this sector involve the treatment of liquid suspensions, with the important requirement of sanitary operation, including clean-in-place and steam sterilisation capability.
As a component of the global market for filtration and other separation equipment, the food and beverage sector is one of the larger, but more particularly, it is also one of the most varied in terms of types of equipment utilised in order to meet its markets’ demands. At the retail level the number of products is huge, with that number multiplied by the need to provide equivalent products to satisfy different religious and ethnic groupings in the same geographical areas – all of which must be supplied by the bulk processing sector. It is estimated that the market in 2014 for all kinds of such equipment, including sales of spares, throughout this sector, will be close to $3.7 billion, which represents about 7.5% of the total world market for all filtration and sedimentation equipment.
In the more traditional of its production processes, which still play an important part in food and beverage processing, this is quite a mature sector, with steady growth close to historical changes in GDP values, but there are some exciting developments as well. New and replacement production lines are regularly being installed in all regions of the world, with strong growth in Asia, especially as the large economies of India and China, and increasingly Indonesia, move quite rapidly towards higher standards of living, with very different dietary requirements.
The need to supply food and beverages for expanding populations, desirous of eating at increasingly higher standards, provides the prime driver for the food and beverage market globally, in turn driving the demand for food and beverage processing equipment, at a rate at least keeping up with the general economic growth of the world, and probably mostly exceeding it.
The search for better quality is a natural part of increasingly higher eating standards, which can be produced by delivering a more attractive product. One of the factors leading to higher added-value is the flavor of the product, which should obviously be retained (if not heightened) during the processing activities. Foodstuffs, whether raw materials or final products, are easily denatured during processing, so that a filtration process is advantageous because it usually occurs at little higher than room temperature.
Higher purity at all stages of food and beverage production is another factor in product quality, which offers further scope for the application of filtration and related equipment. The rise in popularity of organic farming and food production has been promoted by concerns over safety of ‘processed foods’ (although not without some doubts as to the actual reality of benefits with organic products).
Food and beverage industries:
The full range of processing activities included in the food and beverage sector is:
- processing of meat, fish and their solid products (excluding animal oils and fats);
- processing of fruit and vegetables and their solid products (excluding fruit and vegetable oils, fats, and juices);
- processing of oils and fats from animal and vegetable sources;
- production of milk and other dairy products (cheese, yoghurt, etc);
- milling of grain and corn, and manufacture of cereal and starch products;
- production of animal feedstuffs (ie, food for husbanded animals, and domestic pets);
- production of bread, sugar, cocoa and confectionery;
- processing of tea and coffee;
- production of beverages (alcoholic and non-alcoholic), including fruit and vegetable juices, and other soft drinks;
- processing of mineral water.
Of these ten sub-sectors, the process use of filtration and sedimentation is found in all of them, and is very important to some of them. Almost all kinds of separation equipment can be found in use in this sector. (The distinction is made here between process filters, those that are an essential part of the production process, and which are the intended subject of this article, and utility filters, which are involved in services provided to most production processes, such as pneumatic or hydraulic systems, and which are not intentionally covered, because they are very largely the same in whichever industry they are found.) The process filters and centrifuges are used in the preparation of ingredients, in the production process itself, in the purification of products, and in the recycling or treatment of waste streams.
The industry has a number of large companies, with a host of smaller ones. Nestlé is by far the largest of the food producers, the next largest being Unilever, closely followed by Cargill, the largest private company in the USA. This comparison of size is complicated by the other facets of business, as in the case of Unilever, which is also large in the household products business. The leading soft drink companies are Pepsico and Coca Cola, in which the corporate boundaries are further blurred by their being food manufacturers of considerable size. The leading brewer, after much merging activity, is ABInBev, while the merger of Constellation Brands (of the USA) with Hardy (of Australia) has formed the world’s largest wine company.
The simple definition of the whole food sector is that food processing takes clean, freshly harvested crops or freshly butchered animals, and uses them to produce attractive, marketable food products, with an adequate shelf-life. Similarly beverage processing takes clean fresh water and, with appropriate admixture of fruit and vegetable components, uses it to make a wide range of drinks products with global appeal.
Separation equipment has two primary functions within these tasks: to keep the processes, food or beverage, as free as possible from harmful micro-organisms, and to prepare the raw ingredients in their best state to produce the right formulation for inclusion in a final product or for subsequent processing. The hygiene task requires similar kinds of equipment to that employed in the pharmaceutical sector, or in medical and health processing: the major problem being to prevent entrance of micro-organisms into the processing zones or packaging areas. The separation equipment used for this purpose will mostly be very fine cartridge filters in HEPA or ULPA grades, or membrane filters.
It follows that one of the most important characteristics of the separation equipment used in the food and beverage industries is the need for it to be able to operate in a state of scrupulous cleanliness. Contact surfaces will normally be of polished stainless steel, and the whole equipment should be easily cleaned, preferably by some kind of clean-in-place process.
The cleaning processes must allow sufficient residence time for the solutions to do their job. Square corners, dead ends and threaded joints should be avoided in contact with process materials, and surfaces should be sloped so that liquids may drain from them. Care must be exercised for process materials that involve salt solutions, as these can attack stainless steel, so glass-lined equipment may be preferred.
To offset this need for high quality materials in food and beverage processing, it is mostly true that equipment for this sector does not have to withstand the severe processing conditions found in some chemical or pharmaceutical operations. Indeed the most severe operating parameters may well be those involved in steam sterilization or an aggressive clean-in-place solution.
High specification filter media:
The protective function just described employs relatively simple filters, which rely on high-specification filter media for their performance. By contrast, it is probably true that every possible type of filter, centrifuge or sedimentation system is in use somewhere in the world on some process within the food and beverage sector.
Some characteristic food and beverage applications include:
- the use of basket centrifuges in the production of table salt;
- the separation of cream from milk in a disc centrifuge – for which this type of centrifuge was invented;
- the further purification of water by membranes to serve as a food or beverage ingredient;
- the use of a rotary vacuum drum filter in the separation of sugar juice from settled-out mud, followed later by a ‘sugar centrifugal’ to recover the pure crystallized product;
- the purification of starch in batteries of hydro-cyclones, which provides one of the key uses of the hydro-cyclone;
- the refining of vegetable seed oils, after washing with water, in an array of tubular or disc centrifuges, followed, usually, by winterizing (de-waxing) in vacuum filters;
- among many separation activities in a brewery or a distillery, the de-watering of separated grains in a filter press or decanter centrifuge, and the clarification of the product in a sheet filter.
And, of course, the need in most food and beverage factories for the treatment of often very concentrated liquid wastes, requiring the full gamut of treatment stages, from oil and grease separation (in a lamellar separator), followed by primary settlement (in large sedimentation tanks), then secondary activated treatment (in aerated tanks) with separation of the surplus sludge in a filter or another settlement tank. The process will then finish with tertiary treatment, possibly a biological one, or, increasingly commonly, a membrane micro- or ultra-filtration stage, to deliver recycled water of a similar standard to the fresh ingredient water. The secondary stage is increasingly being undertaken in a membrane bio-reactor.