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Deposit detectors in spray drying processing lines Disclosure Number: IPCOM000234611D
Publication Date: 2014-Jan-22
Document File: 4 page(s) / 48K

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Deposit detectors in spray drying processing lines

Monitoring of possible powder deposits and build-up is an increasing demand in the spray drying business.

The time between each clean-in-place (CIP) of spray drying lines is often based on pure experience, leading to unnecessary process shutdowns as well as unforeseen deposit problems. There is a wish to maximize the time between each CIP and to ensure that the proper action is taken if deposits develop during operation.

Impact hammers are today used to minimize the amount of deposits on the chamber walls, ducts, and transport systems and so on. It has been suggested to investigate whether the state of the chamber during operation can be monitored by comparing the chamber's response characteristics to a hammer impact with that of a clean chamber [Li]. Both size and location of deposits are interesting, also for future chamber designs.

This overview will summarize some of the most important means of detecting powder deposits and build-ups in spray drying processing lines used for example for products within dairy, food, chemical, agro-chemical, energy, biotechnology, pharmaceutical, healthcare and many more, and are not limited in application to the examples given but are wide open for all such products.

Spray drying processing lines

Spray drying processing lines consist of a row of technologies for preparing feeds, for atomization/droplet generation, for drying liquid feeds, pastes and solids, for post- treatment and handling of the final dry product.

Spray drying is the most widely used industrial process involving particle formation and drying [Masters]. It is highly suited for the continuous production of dry solids in either powder, granulate or agglomerate form from liquid feedstocks as solutions, emulsions and pumpable suspensions. Therefore, spray drying is an ideal process where the end-product must comply with precise quality standards regarding particle size distribution, residual moisture content, bulk density, and particle shape.

Spray drying involves the atomization of a liquid feedstock into a spray of droplets and contacting the droplets with hot air in a drying chamber. The sprays are produced by either rotary (wheel) or nozzle atomizers. Evaporation of moisture from the droplets and formation of dry particles proceed under controlled temperature and airflow conditions. Powder is discharged continuously from the drying chamber. Operating conditions and dryer design are selected according to the drying characteristics of the product and powder specification.

Every spray drying system consists of feed pump, atomizer, air heater, air disperser, drying chamber, powder recovery means such as cyclones and bag filters / systems for exhaust air cleaning are combined into a system that meets individual operational safety and environmental protection. All systems can be provided with pre- and post-

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treatment equipment, as for example fluid bed dryer/cooler, agg...