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Large spray dryer common faults and solutions

Technical Knowledge 2019-02-22 15:06:14
Large-scale spray dryers are highly regarded by many companies because of their fast drying speed, good drying effect and continuous production process. However, as the use time increases and the relevant parameters are set incorrectly, the spray dryer will cause some problems in the production process. After more than ten years of experience in the company, we have listed some common problems and solutions:

1. 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 amount of feed to increase the exhaust air temperature.

2. Low purity and excessive 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) The spray dryer equipment is not thoroughly cleaned. 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.

3. The product powder is too fine, the running phenomenon is serious, and the product yield is low.

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. Excessive loss of running powder greatly affects the yield of finished products. The general reason is that the separation effect of the cyclone separator is poor. If this happens, check whether the cyclone is deformed by knocking or collision; improve the airtightness of the inlet and outlet of the cyclone, and check whether the inner wall of the spray dryer 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.

4. Sticky wall phenomenon is serious

The main performance is that the spray dryer has a sticky wet powder everywhere in the drying chamber. The reason is that the feed amount is too large to be fully evaporated; the drying chamber is insufficiently heated before the spray dryer starts to spray; when the spray is started, the discharge flow rate is adjusted too much; the added feed liquid is unstable.

For the different reasons mentioned above, the following measures can be taken in sequence:

Appropriately reduce the feed amount; 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 until appropriate; check the pipeline for blockage, adjust the solid content of the material, and ensure the flow of the feed liquid. Sex.

5. Centrifugal spray dryer nozzle speed is too low, evaporation is too low

Mainly because the centrifugal spray dryer nozzle parts have failed, so stop using the nozzles and check the internal parts of the nozzles.

The reason may be: the air volume of the whole system is reduced; the inlet temperature of the hot air is low; the equipment has air leakage, and cold air enters the drying room. The remedy is: check whether the speed of the centrifugal spray dryer is normal; check whether the position of the centrifuge control valve is correct; check whether the air filter and air heater pipe are blocked; check whether the grid voltage is normal; check whether the electric heater works normally; Whether the components of the equipment are connected or not.

6. There are noise or vibration when the centrifugal nozzle is running.

Mainly due to the improper cleaning and maintenance of the spray dryer nozzle, there is residual material in the spray disc 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 dryer disk. If it should be cleaned in time; if the spray dryer spindle is abnormal, replace it and re-adjust or replace the balance of the centrifugal disk.

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