Can loss in weight feeder or loss in weight feeding machine feed maleic anhydride, what specific conditions?
A loss-in-weight feeder (loss-in-weight feeding machine) can be used for feeding maleic anhydride, but the following specific conditions need to be met:
Characteristics and Challenges of Maleic Anhydride
1. **Physical State and Temperature Requirements**
- Maleic anhydride is a solid at room temperature (with a melting point of approximately 52-54°C) and needs to be heated to a liquid state (usually 60-80°C) for stable conveying.
- A **heating and heat preservation system** (such as an electrically traced pipeline or a jacket heating system) should be equipped to prevent solidification and blockage.
2. **Strong Corrosiveness**
- Maleic anhydride has strong corrosiveness to metals (especially ordinary stainless steel), so **corrosion-resistant materials** need to be selected:
- Materials for parts in contact with the material: **PTFE (polytetrafluoroethylene) lining, Hastelloy C276**.
- Sealing elements: **fluororubber (FKM) or perfluoroelastomer (FFKM)**.
3. **Safety Protection**
- Liquid maleic anhydride is prone to volatilizing irritating gases, so a **fully enclosed design** is required, and an **exhaust gas treatment system** (such as condensation recovery or activated carbon adsorption) should be configured.
- The equipment needs to meet the **explosion-proof certification** (such as ATEX) to avoid risks caused by high temperature or static electricity.
Equipment Selection and Modification Suggestions
1. **Configuration of Suitable Machine Types**
- **Heating type loss-in-weight feeder**: The hopper and conveying pipeline are integrated with an electric heating/circulating heat medium jacket to maintain the temperature above 60°C.
- **Corrosion-resistant structure**: Sensors, valves, and pumps in contact with the material need to be made of PTFE or Hastelloy materials.
- **Anti-crystallization design**: Screw pumps or vibration-assisted discharging are used to avoid local cooling and crystallization of the melt.
2. **Optimization of Operating Parameters**
- **Temperature control accuracy**: Within ±2°C to avoid excessive thermal decomposition (maleic anhydride may generate maleic anhydride gas at high temperatures).
- **Feeding accuracy**: It is recommended to select a **high-resolution weighing sensor** (≤0.1% F.S.) to ensure the accuracy of minor addition.
3. **Supporting Systems**
- **Nitrogen protection**: Fill the hopper with nitrogen to isolate oxygen and prevent oxidation side reactions.
- **Emergency cooling**: Start the cooling program in case of abnormal shutdown to prevent the residual material from carbonizing.
Precautions
- **Direct contact with water is prohibited**: Maleic anhydride hydrolyzes violently when it comes into contact with water, so strict moisture prevention is required (blow dry air inside the equipment).
- **Maintenance and cleaning**: Thoroughly remove the residual material after shutdown to avoid solid blockage (the pipeline can be purged with hot nitrogen).
- **Safe operation**: Personnel need to wear gas masks and acid-resistant gloves, and emergency flushing facilities should be provided on-site.
**Summary**
Maleic anhydride can achieve precise feeding through a **customized loss-in-weight feeder**. The key lies in:
- **Corrosion-resistant materials + precise temperature control + fully enclosed explosion-proof design**.
See our loss in weight feeding machine for MAH feeding.
It is recommended to communicate in detail with the equipment supplier about the process parameters (temperature, flow rate, environmental requirements, etc.) and conduct small-scale tests to verify the stability of the system.
Nanjing PEGE can surely provide reliable liquid loss in weight feeder to feed Maleic Anhydride for clients all over the world.