What pumps are commonly used to transport MDI?

MDI (diphenylmethane diisocyanate) requires special pumps and valves for transportation and control in industrial applications, as it has high viscosity and is somewhat corrosive to materials. Here are some common types of pumps and valves: ### Pump selection 1. **Gear pump** – Gear pumps are often used to transport viscous liquids such as MDI, as they can provide a continuous and steady flow. They can withstand high pressures and are suitable for MDI transportation needs. 2. **Diaphragm pump** – Diaphragm pumps can handle liquids containing solid particles, making them a good choice for transporting MDI that may contain impurities. Furthermore, diaphragm pumps have good sealing properties, which can prevent MDI leakage. 3. **Screw pump** - Screw pumps are also suitable for transporting high-viscosity liquids, operate smoothly, and require relatively simple maintenance. ### Selection of valves 1. **Ball valves** – Ball valves are often used to control the flow of viscous liquids due to their excellent sealing properties and low fluid resistance. 2. **Butterfly valve** – Butterfly valves are suitable for regulating large flow rates; they have a simple structure and are easy to operate, making them ideal for rapid shut-off and flow regulation in MDI systems. 3. **Diaphragm valve** - Diaphragm valves can provide excellent sealing performance, especially when handling corrosive or viscous media. Their sealing materials can be selected based on the properties of MDI to improve corrosion resistance and durability. ### Automatic control: For automatic control, electric or pneumatic actuators connected to PLCs (Programmable Logic Controllers) are typically used to operate these pumps and valves. This enables remote control and automated operations, improving production efficiency and safety. When selecting pumps and valves, it is also necessary to consider the temperature, pressure, and chemical properties of MDI, as well as the overall design of the system. It is recommended to work with equipment suppliers or professional engineers to ensure that the most suitable equipment for your application requirements is selected. .

The main issue I’m facing here is that after opening and closing the ball valve multiple times, MDI starts to leak

What if we change the ball valve to a V-ball valve?

I haven’t tried it. The main issue is that MDI tends to solidify; frequent opening and closing can cause wear on the seals, and its liquid form is sticky, making it difficult to work with

The previous supplier was a foreign-owned chemical company that specialized in MDI; gear pumps were used to transport MDI, with electric heating provided for the pipelines

There are many grades of MDI, and viscosity is an essential parameter for selection. Generally, a shielded pump is used for large quantities of MDI. Small-scale unloading and transfer in barrels is accomplished by gear pumps.

MDI-100 is being used

MDI100 has a short shelf life and decomposes when heated. The cartridge valve is either dimerized or has formed bubbles due to moisture. For small-scale unloading and extraction in barrels, hot-air rollers are generally used; once the appropriate temperature is reached, the liquid is transported. After transportation, the remaining material must be cleaned with a solvent, and the pipelines should be protected with dry nitrogen. Gear pump + ball valve; residues remaining in the gear pump’s gaps are difficult to remove. Shielded pump + ball valve; residues also remain on the stator of the shielded pump, making it difficult to clean. A diaphragm pump + ball valve is more suitable.

In the production and transportation of MDI (diphenylmethane diisocyanate), the commonly used pump and valve types are as follows: Pump selection Diaphragm pump: Features: Good sealing performance, suitable for transporting high-viscosity, corrosive, or flammable and explosive media. Applications: Commonly used for transporting chemicals such as MDI. Gear pump: Features: simple structure, suitable for transporting high-viscosity liquids, and stable flow rate. Applications: Suitable for transporting viscous liquids such as MDI. Screw pump: Features: Suitable for transporting high-viscosity, particle-containing media, with stable flow and low pulsation. Application: Used for transporting viscous liquids such as MDI. Valve selection: Ball valve: Features: Good sealing performance, simple operation, and corrosion resistance. Applications: Suitable for the automatic control of chemical media such as MDI. Butterfly valve: Features: Simple structure, rapid opening and closing, suitable for large-flow control. Application: Used for flow regulation in media such as MDI. Diaphragm valve: Features: Good sealing performance, suitable for corrosive media. Applications: Suitable for the automatic control of chemicals such as MDI. Control valve: Features: Enables precise control of flow and pressure, with a high degree of automation. Application: Used for precise flow and pressure control in media such as MDI. Automatic control system: PLC control system – used for the automated control of pumps and valves to achieve precise regulation of flow rate and pressure. Sensors and instruments: such as flow meters, pressure sensors, etc., used for real-time monitoring and feedback control. In summary, diaphragm pumps, gear pumps, or screw pumps are commonly used for transporting MDI, while ball valves, butterfly valves, diaphragm valves, or control valves are frequently selected as valves. Automatic control systems achieve precise control through PLCs and sensors, ensuring safe and efficient operation.