As a universal filtration and separation equipment, centrifuges are widely used in industries such as chemical, pharmaceutical, petroleum, and pesticide. Due to the wide variety of materials processed by centrifuges, most of which are flammable and explosive, and the high rotation speed of centrifuges, static electricity accumulation is easily generated during rotation. Encountering combustible materials and suitable environmental conditions can easily lead to combustion and explosion accidents.

Specific elements and measures

Below, based on the potential fire and explosion hazards of centrifuges in separating solutions containing flammable and explosive materials;

1. This article analyzes the causes of combustion and explosion accidents and proposes the basic principles of explosion prevention;

2. Propose corresponding safety measures to address potential safety hazards during the centrifugal separation of solutions containing flammable and explosive materials.

　　1. The three elements that cause an explosion

The three elements that cause an explosion are:

A certain concentration of combustible gas,

A certain amount of oxygen,

And enough heat to ignite their ignition source.

The coexistence of the three basic conditions for preventing chemical explosions is the fundamental theory for preventing chemical explosions of flammable substances.

　　2. Explosion proof measures for centrifuges

　　Explosion proof measures for centrifuges

The centrifuge is designed with sufficient safety for all moving parts,

Running without collision or friction, using non-contact braking

The transmission belt adopts anti-static belt and the machine is equipped with electrostatic grounding device

In order to reduce the oxygen concentration inside the centrifuge, the common method is to fill the centrifuge with nitrogen gas to lower the oxygen concentration inside the machine, so that the oxygen concentration inside the machine is below the explosive limit of combustible gases.

It should be noted here that it is simplenitrogen filling deviceOnly fill the centrifuge with nitrogen without checking the reliability of nitrogen filling. When there is an abnormality in nitrogen, it cannot be detected in real time. The centrifuge in operation cannot stop running immediately, which can easily lead to danger!

Therefore, to ensure reliable nitrogen protection, a nitrogen detection device needs to be installed. Common detection methods include nitrogen pressure detection, nitrogen flow detection, and oxygen concentration detection.

1、 Requirements for nitrogen gas source

The purity of nitrogen must meet explosion-proof requirements (purity ≥ 99%);

The nitrogen pressure reaches the required pressure for pressure filtration (if the centrifuge requires pressure filtration);

Nitrogen must undergo dehumidification and dust removal treatment; Require nitrogen to be free of moisture, impurities, and dust. If the moisture content is high, it will affect the corrosion of the centrifuge bearing seat, bearings, and electrical components; If it contains impurities and dust, it will affect the transmission effect and the service life of electrical components, and also affect the impurity content of centrifuge production products. Moisture content requirement: The dew point of nitrogen should reach -20 ℃; Nitrogen impurity requirements: Nitrogen needs to pass through a filter with a precision of 1 micron;

Nitrogen temperature: room temperature (special circumstances require heating or cooling);

Nitrogen: does not contain oil or gas. If it contains oil or gas, it will affect the normal operation of electrical components;

Nitrogen does not contain harmful gases such as H2S and SO2, otherwise the oxygen analyzer sensor will be damaged, affecting the detection of oxygen content.

2、 Basic process of nitrogen protection

Nitrogen first passes through a nitrogen filter and a pressure reducing valve before entering the centrifuge; Thus, the air is displaced from each chamber of the centrifuge; 3. Detect oxygen concentration through an oxygen content analyzer; If the oxygen concentration meets the explosion-proof requirements, the centrifuge can be started for operation. Continue nitrogen replenishment of the centrifuge after normal operation.note

So, as mentioned above

Oxygen content determination and nitrogen supplementation operation

What does it specifically refer to?

Next, the editor will take you to understand

The specific content of these two points!

　　The process of oxygen content detection

Ensure that the nitrogen gas source meets the specified requirements and that all valves in the nitrogen system are closed

(1) Firstly, add water to the water absorption device, observe the water level through a liquid level indicator, and control the water level height by adjusting it. The water level height ensures that nitrogen can enter the oxygen content meter through the water absorption device when the pressure is low;

(2) Calibrate the oxygen content analyzer. The compressed air first passes through a water absorption device to remove toxic and harmful gases and impurity particles from the compressed air. Then, it is further removed of moisture, oil and gas, and impurity particles through a nitrogen filter. The purified compressed air is passed into the oxygen content analyzer and vented for calibration;

(3) Nitrogen is used to empty the air in the discharge chamber and filtrate chamber of the centrifuge. After a few minutes, nitrogen is almost completely replacing the air inside the centrifuge.

(4) By using an oxygen content measuring device, the gas inside the centrifuge is sucked out for oxygen concentration analysis.

(5) Ensure that the oxygen content analyzer can detect the concentration of oxygen. Maintain the nitrogen pressure within the system between the upper and lower limits of pressure.

For example, the upper limit of oxygen concentration is 4%. When the system oxygen concentration is below 4% or above 4%, the machine will sound an alarm or shut down.

(6) When the oxygen concentration in the system meets the required concentration (detected and displayed by the oxygen analyzer), the centrifuge can be prepared to start.

　　Nitrogen supplementation requirements

Nitrogen passes through the nitrogen filter to the pressure reducing valve; Adjust the pressure of the pressure reducing valve to achieve the required output pressure; After adjustment, do not adjust the pressure reducing valve arbitrarily.

　　Airtight sealing requirements

All parts of the centrifuge that require gas sealing are filled with low-pressure nitrogen to ensure that external corrosive gases do not interfere with the sealing of the shaft seat, so as not to affect bearing lubrication and prevent damage.

From this, we can summarize the following three key points in dealing with flammable and explosive measures when separating materials in centrifuges, as well as precautions when filling nitrogen gas!

1、 The coexistence of the three basic conditions for preventing chemical explosions is the fundamental theory for preventing chemical explosions of flammable substances.

2、 Inject nitrogen into the centrifuge to reduce the oxygen concentration inside the machine and lower it below the explosive limit of combustible gases.

3、 To ensure reliable nitrogen protection, a nitrogen detection device is required. Common detection methods include nitrogen pressure detection, nitrogen flow detection, and oxygen concentration detection devices.