Application Guide- Spray Drying
Spray Drying Application Guide Increase Output in Spray Drying Applications Improve Production and Product Quality All
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Spray Drying Application Guide
Increase Output in Spray Drying Applications Improve Production and Product Quality All Year Round
Munters is the world leader in dehumidification Munters is the largest manufacturer of dehumidifiers in the world. Since developing the first desiccant dehumidifier in the late 1930’s, Munters has continued to innovate in the fields of dehumidification and energy recovery. Our long history and extensive expertise in dehumidification makes us the premier choice for your dehumidification needs.
T
he technology of spray drying systems and spray dryers are widely used in food, pharmaceutical and industrial applications converting liquid solutions to powder or granules. Companies utilizing spray drying technology, prefer the dry winter climate to the humid summer climate for increased production and quality. In the winter time, water content in the air is low which creates optimal operating conditions. In the summer climate, humid conditions have a greater impact on production quality, dry time and overall production efficiency. Additionally, the constantly changing moisture level of outside air during production can have a negative impact on consistent quality output. It is necessary during the spray drying process to stabilize all parameters of the operation to optimize production and improve efficiency. Using desiccant dehumidification can make this possible.
TYPICAL SPRAY DRYING APPLICATIONS Food Milk powder, coffee, tea, eggs, cereal, spices, flavorings Pharmaceutical Antibiotics, medical ingredients, additives Industrial Paint pigments, ceramic materials, catalyst supports
Minimum 20% of the production is lost each year
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Figure 1: Typical spray dryer
In spray drying applications, it is critical that moisture is controlled
0 -5
80
-10
70
Humidity Gr/Lb
-20 50 -25 40 -30 30 -35 20
-40
10
-45
0
-50 January
February
March
April
May
June
July
August
September
October
November December
SPRAY TOWER PROBLEMS Production rate varies by season
Production stops
Drying time too long
Lack of flexibility
Inconsistent quality of the powder
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Spray Drying Application Guide
Product scrap
% lost of production
-15 60
By dehumidifying the incoming air, maintaining the same low moisture content throughout the year is easy. This allows for stable inlet conditions, enabling consistent quality and increased performance from the spray drying process. Munters has developed a range of special high performance dehumidifiers which enable this to happen. Munters dehumidifiers control precise moisture content of the incoming air, which provides the following advantages to the spray drying process: •
• •
Consistent production all year. Production is no longer affected by outside conditions. No more production stops in the summer due to weather conditions, also eliminating the need for frequent parameter adjustments. Consistent quality all year. Having stable dry inlet conditions means consistent quality. Less cleaning time. Less product sticking to the wall of the spray tower.
Fan
Bag Filter
OUTLET DUCT
FEED
FINES
Feed Screw Reactivation Air
FRESH AIR
Wet Air
Air Filter
Fan
Air Heater
DRY/COOLED PRODUCT
Dry Air
Pre-Cooled Outside Air
FRESH AIR
Air Filter
Cool / Demist Reheat
Fan
Figure 2: Munters supplies multiple products for spray drying processes, including indirect gas-fired heaters, heat exchangers, desiccant air dryers. All of these systems can be used to control the temperature and humidity of the process air.
Summary
Munters dehumidification can improve the performance of the spray drying application by providing a low moisture level to the spray dryer all year round. The moisture in the incoming air to the desiccant is absorbed by the desiccant rotor. The air coming off the dehumidifier system can be controlled to the desired moisture content. As the process is exothermic, the temperature difference is dependent on the amount of moisture removed, but can be up to 120°F. This means the spray dryer has less work to do to achieve its temperature of the entering air into the chamber. With summer conditions, outdoor air introduces a huge quantity of water in the spray tower. For example an outdoor air condition of 77°F at 61% RH (85 gr/lb) and an airflow of 50,000 CFM, then 2600 lbs. of water are introduced per hour into the spray tower. The Munters GTR rotor makes the system much more efficient. An outdoor air condition of 77°F at 61% RH (85 gr/lb) passes through the Munters system and provides process air of 50,000 CFM at 147°F and 14 gr/lb. This means only 450 lbs. of water are introduced per hour to the spray tower — a savings of almost 2200 lbs. of water per hour. In addition over 4,000,000 BTUH is saved because of the higher air temperature due to the dehumidification process. With 2200 lbs. of water less per hour introduced into the tower and a 55% slurry, a production increase equal to 29 tons of extra powder (product) can be produced in one summer day. Munters equipment has been successfully used in many spray drying situations worldwide.
GTR Desiccant Rotor
Munters GTR Desiccant Rotor was designed with the spray drying application in mind. The GTR Rotor provides greater grain depression (lower process air moisture content) than standard desiccant wheels when exposed to outside air. This allows for the elimination of pre-cooling. Another advantage of the GTR Desiccant Rotor is the higher outlet temperature (because of the larger amount of moisture removed), which can reduce the energy required for process heating to the high temperatures that spray dryers require. With Munters GTR technology, applications such as spray drying benefit with a reduction of moisture content while increasing the process air temperature resulting in production increases from 15–20%. Installations include:
Nestle Lesaffre Sofivo Aromes de Bretagne Lactalis Solaipa
Spray Drying Application Guide
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Munters is a global leader in energy efficient air treatment solutions. Munters manufactures engineered products that can economically control humidity and temperature, provide energy recovery, and/or utilize direct or indirect evaporative cooling for comfort, process and environmental protection. With permanent or temporary solutions, Munters offers a wide variety of options to meet specific climate, application and budget requirements. Munters has net sales approaching $1 billion USD with more than 20 manufacturing facilities across the globe and sales offices in over 30 countries. Munters employs approximately 4,300 people worldwide. For more information see www.munters.us
Munters Corporation Tel: (800) 843-5360 E-mail: [email protected] www.munters.us AG0024-00
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