CIP Cleanable Tangencial Bag Filter
Two basic parameters in the design of spray dryers are process performance and environmental impact. Retaining and recovering the fines produced during spray drying allows increasing production yield, given that those fines would be lost through the chimney, accounting as a direct loss of final product.
Also, growing environmental demands place very strict limits to the amount of fines allowed to escape the drying plant.
This is way the use of filters to retain fines suspended in the exhaust air is highly recommendable. SEI Contreras Engineering provides CIP cleanable cyclonic bag filters that combine both filtering and cyclonic separation operations in one equipment, reducing the required investment in installations, ducts and civil works in the spray drying plant while ensuring optimal product retention. It is no longer necessary to install one or two primary cyclons and then a conventional bag filter. Instead, only one cyclonic bag filter can be used.
Besides, including a CIP cleaning system and choosing adequately the bags material, these equipments can be cleaned without opening, a common problem for conventional bag filters.
Also, bag filters can be incorporated without problems to existing installations that only have cyclons as a separation method. This is the very common case of milk powder spray drying plants that started drying cheese whey. While milk powder is adequately separated in cyclons, whey powder usually passes through the cyclons and out through the chimney due to its low granule size. This whey powder loss can be detected as a white powder column above the chimney, and it is dispersed by wind to the plant and its surroundings which is a serious environmental infraction, but also a hygienic threat to the drying plant, because the powder is an excellent feed for insects and bacteria. This attracts flies and also generates bad odors in the plant, both very negative issues while being audited for certification or by a customer.