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In comparison with domestic large-size vertical drying equipments, our horizontal dryer based on foreign advanced technologies is more compact in structure, smaller in floor area and easier for operation and maintenance. With advantages in energy saving, product quality and automation, it is an ideal upgrade of vertical drying equipments.
For horizontal dryer, powders are centrally discharged, namely only one powder outlet is design to solve the problem of material accumulation in the pipeline, ensure the consistency of granularity and moisture content of powders and quality of product, improve the product condition, reduce the retention time of powders in the pipeline after drying and effectively protect the active ingredients of product. For vertical dryer, however, there are various powder outlets, and only the finest powder can reach the final bag type dust collector; therefore, the moisture content and granularity of product vary with powder outlets, materials may accumulate in the pipeline, the retention time after drying is long, both internal and external conditions of product are poor, and active ingredients are lost seriously.
The horizontal dryer of compact structure and reasonablelayout can enable the processes of atomization of material, dewatering and drying with hot air, collection and delivery of powders, venting, dedusting and discharge of powders in the same cabinet, thus it has a small floor area and it is easy for operation and maintenance. For example, a 1300kg/h horizontal dryer is (L) 15m× (W) 8m× (H) 10m in size, while a vertical dryer of the same water evaporation, that adopts the design of vertical spraying downward to form droplets and uses air flow for delivery of powders as well as the separated cyclone separator and bag type dust connector, has a higher tower body and larger floor area. |
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Horizontal dryer is easy for operation. It is highly automatedand has low failure rate and no dead angle. Only a high-pressure washer is required for internal cleaning and maintenance, and workers can stand and work easily,without any potential safety hazard. In the case of vertical dryer that is dozens of meters high above the floor, however, it is hard to clean thoroughly, there are dead corners, and operators need to work at heights during maintenance. It is obviously unsafe and difficult for operation.
Advantages of Horizontal Pressure Spray Dryer:
Horizontal pressure spray dryer is significantly superior to vertical dryer in use and energy consumption:
For vertical dryer that adopts the design of vertical spraying downward to form droplets and uses air flow for delivery of powders, the tower body is high, and the separated cyclone separator and bag type dust collector must be used; therefore, the floor area is large, and it requires for a high plant with large area; additionally, the moisture content and granularity of powders vary as there are multiple powder outlets and only the finest power can reach the final bag type dust collector!
For horizontal dryer that enables the processes of atomization of material, dewatering and drying, delivery of powders with low-speed circulating scraper, venting, dedusting with bag type dust collector and discharge of powders in the same compact drying cabinet, the floor area is small and the tower height is low. For example, the highest point of 1900kg/h horizontal dryer is 12m only. Additionally, it is safe and easy for internal cleaning.
Heat loss: As the processes of material atomization, dewatering, drying, powder delivery and dedusting are continuously completed in the same compact cabinet and the cabinet body, and even exhaust duct, is covered with a complete insulating layer (100mm thick), heat loss of horizontal dryer is reduced to the lowest. You will not feel hot when you touch the surface of the drying equipment by hand during operation!
Energy consumption: Horizontal dryer is designed with an exhaust gas heat recovery system, which can reduce energy consumption and improve the comprehensive heat utilization ratio of the drying equipment. According to our practical experiences over the years, for a vertical dryer without heat recovery system and subject to heavy radiation loss, the energy consumption is about 1300kcal per 1kg water evaporation. For a 1000kg/h drying equipment, the vertical dryer will consume 430,000kcal more heat per hour! This means 88kg more 5000kcal standard coal or 50.6m3 natural gas (calorific value 8500kcal/m3) is consumed in an hour.
This series of spray dryer is applied in foodstuff industries like animal blood product and other fields. Generally it has its own unique advantages in some certain aspects. Please refer to the aspects for your kind attetnion below:
The space available at the user's site, especially the height.
Liquid name and property: solid contents(or water contents),viscosity,surface tension and PH value;
Dry powder density residual water contents allowed,particle size,and maximum temperature allowed. Dry powder density residual water contents allowed,particle size,and maximum temperature allowed.
Output: shift time daily;
Energy that can be available at user's site: steam pressure, electricity properly,fuel of coal,oil and natural gas;
Control requirement: whether or not the inlet and outlet temperatures should be controlled. Whether the whole control system should be fully automatic or semi-automatic;
Powder collection requirement: whether it's necessary to use cloth bag filter and the requirement of the environment of the exhausted gas.
Other special requirements;
Typical application of animal blood products processing in the WZ Series horizontal spray dryer.
One. General description: This series of spray dryer is applied in foodstuff industries like animal blood product and other fields. Generally it has its own unique advantages in some certain aspects.
Two. Animal blood products processing process briefly:
(1)The blood collection system is installed at the slaughter house. The collected pig's blood is pumped into the device equipped with a freezing storage device and heat-insulation. Meanwhile a certain amount of Anticoagulants (such as citric acid salts) matching with the blood amount in weight and concentration is added in.
(2)By the special stainless steel tank truck for blood, the collected fresh pig blood shall be transported to freezing storage tank with heat-insulation at processing factory, where the blood can be kept fresh for 5~7 days.
(3)By a tubular blood separator, the blood is separated into blood plasma solution (about 58% of the total original blood) and the cell solution (approximately 42% of the total original blood).
(4)In order to save energy, the plasma fluid can be concentrated and sterilized ( To the spray drying of the cell solution, usually it do not need the concentration process). Otherwise spray drying may also be directly done on the plasma solution without through being concentrated.
(5) The spray drying is done respectively done on the plasma fluid and the cell solution, and dry products of the plasma protein powder and blood cells protein powder are obtained. Then they enter the inspection, packaging, storage process.
(6) Description: All blood products should be dried at relatively low temperatures, in order to ensure product quality and prevent thermal coagulation. Three.
Spray drying principle:
The working principle of this machine are:
After fully heat-exchange through the heat exchanger (steam + electric heating), the filtered air becomes clean high-temperature hot air (drying medium), and enters the hot air distributor (functioning for air Homogenizer) mounted at the top of the spray dryer's tower, and the high-temperature hot air is conveyed evenly into the drying chamber in a spiral state; at the same time, the raw material liquid is pumped by the screw pump to the atomizer at the top of the spray dryer tower, and the material liquid is dispersed into a fine mist of droplets immediately by high-speed rotating atomizer.
These mist droplets have a great surface area, there is a significant "gradient" on the temperature and humidity to the drying medium (high-temperature hot air), which strengthens the mass- heat transfer process between the gas-liquid phases; the moisture is quickly vaporized after the droplets contact with the drying medium, thus in a short time these mist droplets are dried into a powder product.
Most of the products are collected at the bottom of the cyclone separator, and together with the tail gas (at the moment, after heat exchange, the high-temperature hot air has become the LHV high humidity wasted vapor), a small amount of fine powder was conveyed into the high efficiency bag filter by the draft fan. In the bag filter, the gas and solid is separated, and discharged from the bag filter at the bottom of the rotary valve, and after thorough dust-removal, the tail gas reaches standards of air-emission and is exhausted to outdoor. In the entire drying process, there is the design for over-temperature safety and emergency measures in bag filter.
When it comes blockage by foreign material in the slurry system or feeding is influenced by other factors, drying tower outlet air temperature may exceed 150 ° C, at which time the system will automatically open the emergency air bypass safety valve, and a large amount of cold air rushes into the bag filter as to effectively protect the bag. Four. Features:
4-1 Adopting new M-type atomizer, which is characterized as follows:
4-1-1 capable of producing spherical powders in fine fluidity.
4-1-2 can produce a uniform particle size distribution.
4-1-3 product powder adhesion amount along flight line is reduced.
4-1-4 can adjust the average product particle size.
4-1-5 no blockage trouble
4-2 The hot air distributor body is designed through logarithmic spiral rules, as to ensure uniform distribution of hot air into the drying chamber, and thus it is easy obtain a high and excellent heat- mass transfer efficiency.
4-3 To avoid the product powder from sticking on the drying chamber wall in the long run, the compressed air-driven pneumatic powerful air hammer is applied. Through periodic effective strikes to the inner walls in drying chamber, there is no product powder adhesion on the walls.
4-4 We adopt Niro's latest structural design of dust collector in Europe - high efficiency cyclone separator, which has a large ventilation volume, and raises the separation ratio between gas and solid, which can obtain a recovery ratio higher than 90%to the fine powder product during one time process. 4-5 The dust collector is specially made in DuPont NOMEX film-coated filtration material. This filter bag has such features as: large filtration area, anti-static effect as well as the characteristics of high temperature resistance, thus this type dust collector obtains an effective recovery ratio of up to 99.5%. 4-6 In order to guarantee the stable quality of product, the system adopts PLC automatic program control pattern, completed with digital display system in touch screen, and there is flow chart for working points; fine industrial control configurations can ensure high reliability for the plant's operation, and guarantee that the parameters for proper operation will not be influenced by artificial and natural factors. It industrial control principle is as followings:
4-6-1.The critical control points are composed by imported elements, and they are set interlocking ring upon ring to prevent artificial operation misses;
4-6-2. Inlet air temperature display, control and alarming(TICA), and acoustical-optic alarming for temperature-exceeding;
4-6-3.Outlet air temperature display, control and alarming(TICA), and acoustical-optic alarming for temperature-exceeding;
4-6-4.SSR (SOLID STATE RELARY) realizes precision temperature control, accuracy up to ±2ºC.
4-6-5. The revolution of the atomizer is controlled through frequency-converter; the same with the feeding pump and the exhaust fan. The electronic contact point display for the oil circuit of atomizer can guarantee the reliability of the operation of the equipments;
4-6-6. The feed rate can be controlled through fuzzy technology by adopting an intelligent temperature controller. Model 4 ~ 20mA intelligent temperature controller is adopted to track the inlet air temperature and outlet air temperature automatically; according to the fluctuating outlet temperature, the feed rate matches automatically;
4-6-7. There is the pressure measurement in drying chamber, the indications for differential pressure in cloth-bag filter and cyclone separator and etc.
4-6-8.Locking and interlocking: between atomizer and cooling oil pump; between the atomizer and feed pump; between pressure in the dryer tower and that of the exhaust fan.
