Causes Of Spray Dryer Explosion And How to Prevent It?
In the food, pharmaceutical, and chemical industries, spray drying, as one of the main modern drying technologies, is widely used in products of different properties. Spray dryer safety thus be paid much attention to. As we all know, spray dryer can turn solid materials into dust. And dust explosion is not an unusual thing in most industrial production. In the spray drying process, due to the low moisture content, the too-fine particle size of the dust, and high-temperature inlet air, it is easy to cause a spray dryer explosion. This has happened in past examples, especially in dairy factories and fructose factories.
Therefore, it is necessary to ensure spray dryer safety by preventing such an explosion from happening. Before we propose feasible precautions, first we should know all the possible causes of the spray dryer explosion.
Causes of spray dryer explosion:
1. Spontaneous combustion of some dry powder;
2. Hot solid particles enter the drying room with dry air;
3. Sparks occur from friction between surfaces of metals or hard dry powders;
4. Electricity failure causes power generation;
5. Static power generation;
6. Negligence of the fluctuation of spray drying parameters.
7. Improper operation or other artificial reasons.
It may be very difficult to completely prevent a spray dryer explosion in the drying process. But if we can give high attention to the above points and strengthen management, such explosion accidents could be minimized. Spray dryer safety could be improved through the following measures in the process of installation and production:
Precautions of spray dryer explosion
(1) Select the correct type of drying machine;
(2) Install fire extinguishing equipment during the design and manufacture of the spray dryer;
(3) Smooth material shall be used on the surface of equipment in contact with materials to prevent material deposition;
(4) Install an air filter to prevent dusty waste gas from being sucked into the gas heater in the drying chamber;
(5) Clean the air filters regularly, including flushing the filters;
(6) Check regularly for areas that are prone to deposit during operation;
(7) For centrifugal industrial spray dryer, rotating parts must operate freely and be inspected frequently;
(8) Check electrical and mechanical parts regularly;
(9) Install an electrostatic grounding device;
(10) Keep each dryer part clean.
(11) Thicken wall in the design of the drying chamber.
(12) Most spray drying production is continuous production, that is, 24 hours of non-stop production, dust burning or even explosions often occur at night, people do not track production parameters in time. Spray drying parameters in the production process should be strictly monitored in real time. When the parameters fluctuate, especially when the moisture content of the dust is low, it should be adjusted in time.
(13) In addition, to prevent the spray dryer explosion, we can install an explosion vent valve on the top of the drying chamber; and install a number of valves that can be automatically open when the pressure rises to a certain point.
In any case, safety is the first element of production. Only under this premise, the economic interests and development of enterprises can be fully guaranteed. All manufacturers of spray dryers should take a long-term view on safety production, and all operators should strictly abide by the safety requirements.