Causes and solutions for reactor wall sticking

### Causes and Solutions for Reactor Wall Sticking

#### **Reaction Process Factors**

1. **Reaction Temperature and Time**:

- Low reaction temperatures (<80°C) with ammonium chloride catalysts can hinder pH readings and accelerate reactions, leading to excessive polycondensation and sticking.

- High temperatures and prolonged reactions increase molecular weight and viscosity, exacerbating sticking. Maintain reaction temperatures below 95°C and control heating/cooling rates to prevent sudden temperature changes.

2. **Reactor Wall Temperature Difference**:

- Large temperature differences between the reactor wall and material can cause liquid adhesion.

- Ensure gradual temperature changes:

- Steam temperature <180°C.

- Thermal shock <120°C.

- Cooling shock <90°C.

- Maintain balanced inlet and outlet temperatures for the cooling medium.

3. **Reaction Material Factors**:

- High sulfate content in urea can cause rapid resin cross-linking and sticking. Use industrial-grade urea with sulfate content below 0.01% to prevent this.

#### **Reactor Equipment Factors**

1. **Flow Characteristics**:

- Poor material flow increases sticking. Use radial flow designs and improved agitation methods to reduce sticking.

2. **Dead Corners**:

- Eliminate reactor dead corners through better structural design and increased heat exchange areas.

3. **Feeding Pipe Position**:

- Place feeding pipes to avoid high-concentration liquid accumulation. Use angled nozzles to distribute material evenly and prevent splashing on walls.

#### **Treatment Methods for Sticking**

1. **Inner Wall Treatment**:

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

- Reduce welds to minimize sticking risks.

2. **Dead Corner Elimination**:

- Optimize reactor design to reduce dead spaces and improve material flow.

3. **Cleaning**:

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

By addressing these factors and implementing the suggested solutions, reactor wall sticking can be minimized, ensuring efficient production and maintaining product quality.