Project

• Characteristics:
Generates steam using "flue gas" or "process gas". Unlike other heat exchangers, waste heat boilers have the following characteristics:
1. Operate at high pressure and high temperature.
2. Require adjustment of outlet gas temperature and prevention of dew point corrosion.
3. Structure and materials must withstand high temperature, high pressure, erosion, and corrosion.
4. Consider scaling and blockage.

• Pros and Cons:
1. Energy-saving!
2. Compared to other heat recovery equipment, it has high energy conversion efficiency and rapid response.
3. The disadvantage is the need for boiler water quality control.

• Design Features:
1. Special attention is needed to prevent dry burning issues.
2. The higher the evaporation pressure, the better the heat transfer efficiency.
3. The gas inlet temperature should be as close as possible to the steam saturation temperature to avoid thermal stress.
4. Optimal design steam velocity: 10 to 20 m/s; too fast can cause erosion and pressure drop; too slow can lead to unstable flow.
5. Hot point: around 30°C.
6. Pinch Point: approximately 5°C to 15°C. The lower the Pinch Point temperature difference, the higher the equipment cost.
7. Approach Point: approximately 5°C to 12°C. Keeping the Economizer outlet temperature slightly below saturation temperature aims to avoid evaporation.

• Taiwan Heat Transfer specializes in designing various demisters/liquid-gas separators, which are primarily designed using the following three methods:
1. Gravity separation.
2. Impingement force separation.
3. Centrifugal force separation.
These methods can be used individually or in combination interchangeably. Their design features are as follows:
1. Gravity separation:
   • Suitable for droplet sizes approximately > 100 μm.
   • The principle of separation is that when the airflow flows upward in the container, droplets separate downward when their gravity exceeds the drag force of the airflow.
   • To improve separation efficiency, it is advisable to avoid installing valves, feeding, or unnecessary redirection directly in front of the gravity separator.

2. Impingement force separation:
   • The working principle of this type of demister is to aggregate small liquid droplets by blocking wet steam.
   • Types of designs include: 1. Wire-Mesh Type, 2. Chevron Type, 3. Fiber Bed. The material can be chosen based on the fluid type, and our developed pressure drop demisting efficiency calculation method can assist customers in dealing with unknown demisting efficiency designs.

3. Centrifugal force separation:
   • Utilizes high-speed rotating airflow to subject liquid droplets (or particles) in the airflow to significant centrifugal force, thereby separating them.
   • Centrifugal cyclone separators have a simple structure, low cost, and easy operation and maintenance. They can also be used in high-temperature and high-pressure environments. However, their drawback is the inability to separate droplets or particles with diameters that are too small.

• We can assist in measuring steam dryness.

• Taiwan Heat Transfer possesses welding manufacturing capabilities for various metal equipment. For detailed requirements, inquiries can be directed to our sales department.