The reactor is a type of stainless steel container equipment

### Reactor Wall Sticking: Causes and Solutions

#### **Reaction Process Factors**

1. **Reaction Temperature and Time:**

- Low reaction temperatures (<80°C) with ammonium chloride as a catalyst can lead to uncontrolled reactions and sticking.

- Prolonged reaction times and high viscosity also increase the risk of adhesion.

- **Solution:** Maintain reaction temperatures below 95°C and control reaction time to prevent excessive condensation.

2. **Reactor Wall Temperature Difference:**

- Sudden or excessive cooling creates a significant temperature difference between the reactor wall and the material, causing sticking.

- **Solution:** Operate within reasonable temperature ranges:

- Steam temperature: <180°C

- Thermal shock: <120°C

- Cooling shock: <90°C

- Gradually adjust inlet and outlet cooling medium temperatures for balanced operation.

3. **Reaction Material Factors:**

- Urea with high sulfate content can cause rapid resin crosslinking, leading to solidification.

- **Solution:** Use industrial-grade urea with sulfate content below 0.01% to prevent premature solidification.

#### **Reactor Equipment Factors**

1. **Flow Characteristics:**

- Poor material flow increases sticking risks.

- **Solution:** Use radial flow turbine agitation to improve material movement and reduce wall adhesion.

2. **Dead Corners:**

- Dead spaces in the reactor structure increase sticking risks.

- **Solution:** Design reactors with minimal dead corners and improved heat exchange areas.

3. **Feeding Pipe Placement:**

- Feeding pipes often create dead zones where material accumulates.

- **Solution:** Position feeding pipes at an angle to prevent liquid splashing onto reactor walls and ensure even distribution through constant stirring.

#### **Treatment Methods for Reactor Wall Sticking**

- **Inner Wall Treatment:**

- Polish reactor interiors, heat exchangers, and welds to improve surface finish.

- Reduce the number of welds to minimize sticking risks.

- **High-Pressure Cleaning:**

- Use high-pressure water jets to clean stuck material from reactor walls.

#### **Pressure Considerations for Stainless Steel Reactors**

- **Standard Pressure Ratings:**

- Conventional reactors: 10 MPa (100 atmospheres).

- Customizable high-pressure reactors: 20 MPa or 30 MPa.

- **Pressure Selection:**

- Choose based on experimental requirements; higher pressure ratings are not always necessary.

- Thicker walls for high-pressure reactors increase weight and reduce pressure gauge accuracy.

- For precise readings, use digital pressure gauges, though they are costlier and less aesthetically appealing.

By addressing reaction parameters, equipment design, and operational practices, reactor wall sticking can be minimized, ensuring efficient and high-quality production.