The principle of operation is that air passes through the filter and heater, enters the air distributor at the top of the drying tower, and then enters the drying chamber in a spiral shape evenly. The liquid is pumped from the liquid tank to the centrifugal atomizer at the top of the drying tower through the filter, so that the liquid is sprayed into extremely small droplets, and the liquid is in parallel contact with the hot air, and the water evaporates rapidly. Drying into finished products in a short period of time. The finished product is discharged from the bottom of the drying tower and the cyclone, and the exhaust gas is discharged by the fan.
1 Features:
1.1 Drying speed is fast. After the liquid is sprayed by centrifugation, the surface area is greatly increased. In the high-temperature airflow, 95%-98% of the water can be evaporated instantaneously, and the drying time is only a few seconds.
1.2 Parallel spray drying method can make droplets flow in the same direction as hot air. Although the hot air temperature is higher, the hot air enters the drying chamber and immediately contacts the spray droplets. The indoor temperature drops sharply, and the wet bulb temperature of the material is basically It is unchanged, so it is also suitable for drying heat sensitive materials.
1.3 a wide range of uses. According to the characteristics of the material, it can be used for hot air drying, centrifugal granulation and cold air granulation. Most products with different characteristics can be produced by this machine.
1.4 Since the drying process is completed in an instant, the finished product particles can basically keep the droplets approximately spherical, and the product has good dispersibility, fluidity and solubility.
1.5 The production process is simplified and the operation and control are convenient. Spray drying is usually used for solutions with a solid content of less than 60%. After drying, no further pulverization and screening are required, which reduces the production process and simplifies the production process. For the particle size, bulk density and moisture of the product, within a certain range, the operating conditions can be changed and adjusted, and the control and management are very convenient.
1.6 In order to prevent the material from being polluted and prolong the life of the equipment, all parts in contact with the material are made of stainless steel.
After being sprayed, the liquid is atomized into dispersed particles, and the surface area is greatly increased. After contact with hot air, the drying process can be completed in a very short time. Under normal conditions, at 100 to 150 ° C, 95% to 98% of water can be evaporated within 1 to 3 seconds. Since the drying process is completed in an instant, the particles of the finished product can substantially maintain a spherical shape similar to that of the droplets, thereby having good dispersibility, excellent brewing property, and high solubility.
2 The problems that may occur in production and the causes and remedies are summarized as follows:
2.1 Sticky wall phenomenon is serious
The main performance is the adhesion of wet powder everywhere in the drying room. The reason is:
(1) The amount of feed is too large to evaporate sufficiently;
(2) insufficient heating of the drying chamber before the start of spraying;
(3) When the spray is started, the discharge flow rate is adjusted too large;
(4) The added feed liquid is unstable.
In view of the different reasons for the above problems, the following measures can be taken in sequence: appropriately reduce the amount of feed; appropriately increase the inlet and outlet temperatures of the hot air; when starting the spray, the flow rate should be small, gradually increase, and adjust to the appropriate time; Whether it is blocked, adjust the solid content of the material to ensure the fluidity of the liquid.
2.2 The product moisture content is too high
Exhaust air temperature is the main factor affecting the moisture content of the finished product, so the reason why the moisture content of the product is too high is generally that the exhaust air temperature is too low. The exhaust air temperature can be adjusted by the amount of feed. Therefore, the corresponding measure is to appropriately reduce the feed amount to increase the exhaust air temperature.
2.3 product purity is low, too much impurities
The possible reasons for this are as follows:
(1) The air filtration effect is not good;
(2) The powder is mixed into the finished product;
(3) The purity of the raw materials is not high;
(4) Equipment cleaning is not complete. The remedies available are: check whether the filter material in the air filter is evenly laid, whether the filter is used for too long, if it should be replaced immediately; check the coke powder at the hot air inlet to overcome the eddy current; filter the liquid before spraying ;Re-clean the device.
2.4 product powder is too fine
Too fine a product particle will affect its solubility and brewing performance. The reason is that the solid content is too low or the feed amount is too small. The remedy is to increase the solid content of the feed liquid, increase the feed amount, and increase the inlet air temperature.
2.5 running powder phenomenon is serious, product yield is low
Excessive loss of running powder greatly affects the yield of the finished product. The general reason is that the separation effect of the cyclone separator is poor. If this happens, check whether the cyclone is deformed due to knocking or collision; improve the airtightness of the inlet and outlet of the cyclone, and check whether the inner wall and the discharge port are blocked. Of course, the separation efficiency is also related to the specific gravity of the powder and the size of the particle size. Some materials can be added to the second stage dust removal as needed.
2.6 Centrifugal nozzle speed is too low
Mainly because the centrifugal nozzle parts have failed, so stop using the nozzles and check the internal parts of the nozzles.
2.7 evaporation is too low
The reasons may be: (1) the air volume of the whole system is reduced; (2) the inlet temperature of the hot air is low; (3) the equipment has air leakage, and cold air enters the drying room. The remedy measures are: (1) checking whether the speed of the centrifuge is normal; (2) checking whether the position of the centrifuge control valve is correct; (3) checking whether the air filter and the air heater pipe are blocked; (4) checking whether the grid voltage is normal. (5) Check that the electric heater is working properly; (6) Check whether the components of the equipment are connected or not.
2.8 There is noise or vibration when the centrifugal nozzle is running
Mainly due to the improper cleaning and maintenance of the nozzle, there is residual material in the nozzle or the main shaft is bent and deformed. It may also be that the centrifugal disc is not well balanced. Solution; check if there is any residual material in the spray disk, if it should be cleaned in time; if the spindle is abnormal, replace it; re-adjust or replace the dynamic balance of the centrifugal disk.