Dryer image courtesy of Carrier Vibrating Equipment, Inc.
Drying has long played an important role in the history of the development of industry. In fact, far before the concept of industry was conceived of by anyone, ancient civilizations were drying goods and agricultural products for varying purposes and in varying ways. In that sense, the role of drying in our economies and in our lives has not changed. What has changed is the way that we dry things and the scales on which we do it. Since the advent of industrial drying equipment, drying became possible on scales never before imagined, and this made the production of certain products possible on larger scales than had ever been possible before.
In the context of food processing and production, industrial drying equipment such as flash dryers and conveyor dryers made the large-scale, rapid drying of food ingredients a possibility. Grain dryers, for example, are used to dry very large quantities of grains before they are sent to ethanol plants, food processing facilities and other destinations. Freeze dryers made the preservation of food possible in ways that had never been possible before. Without freeze drying, supplying astronauts with food that can be transported to space and eaten there would have been a challenge. Rotary heaters make the large scale drying of industrial chemicals possible, which makes the processes that involve the use of those chemicals possible on large scales.
This is what industrial drying technologies are all about: improving upon an age-old and comparatively basic activity that has been in practice for millennia. Industry has responded to the varied drying needs of industry and commerce with an extensive variety of different drying equipment, and unless humanity suddenly ceases to need to dry things, industrial dryers will continue to be among the most important industrial tools we use.
I agree. As an operation of prehistoric origin, drying is one of the oldest and most common functions of processing. It is normally not associated with innovation. It is interesting to note, however, that about 250 patents – the titles of which contain the words “dryer”, “drier,” or “drying” – are issued by the U.S. Patent Office every year.
Today, there are over 200 variants of industrial dryers found in practically all major industrial sectors and some 50,000 materials are estimated to require drying on varying scales. There is, however, no “silver bullet” in drying technology. Drying and dewatering is a combination of science, technology and art (or know-how based on extensive experimental observations and operating experience).
The significant R&D growth in drying and dewateringin the western world was triggered by the energy crunch of the early 1970s which increased the cost of drying several-fold within only a few years. Energy conservation still remains one of the main concerns in drying today.
The majority of novel drying technologies, which evolved through a process of evolutionary improvements, were built to offset some or all of the limitations faced in operating conventional dryers. Novelty per se is not adequate justification for embracing new technology; it must be technically superior and cost-effective compared to the current technology.
For drying technologies, one or more of the following attributes may call for an innovative replacement of existing products, operations, or processes:
• New product or process not made or invented heretofore.
• Higher capacities than current technology permits.
• Better quality and quality control than currently feasible.
• Reduced environmental impact.
• Safer operation.
• Better efficiency (resulting in lower cost).
• Lower cost (overall).
• Better control, more flexibility, ability to handle different products.
This is an excerpts from an article featured on Drying titled: Feedstock Drying: No “Silver Bullet” appearing in the the upcoming February edition of Biomass Products & Technology (BPT) http://www.gobiomass.com/