Introduction

Desalters play a crucial role in the oil refining process by removing inorganic salts, water, and sediment from crude oil. Their efficiency is vital for ensuring the downstream processes work smoothly. However, some desalters produce oily water that can disrupt the functioning of emulsion treaters. This issue can lead to operational inefficiencies and increased costs. In this blog, we explore the reasons behind this problem and potential solutions to mitigate it.

Understanding the Desalter Process

To comprehend why some desalters produce oily water, it's essential to understand their basic function. Desalters operate by combining crude oil with water to wash out impurities. The mixture is then subjected to an electric field, causing water droplets to coalesce and separate from the oil. Ideally, this process results in clean oil ready for further refining and wastewater that’s free of oil.

Challenges in the Desalting Process

Several factors can contribute to desalters producing oily water:

1. **Improper Emulsion Breaking**: The primary goal of desalting is to break emulsions effectively. Emulsions are mixtures where tiny water droplets are dispersed in oil or vice versa. If the emulsion is not broken properly, oil can remain in the water phase, causing problems for downstream processes.

2. **Inadequate Electrostatic Field Strength**: The electric field strength in desalters must be optimized to ensure effective separation. If the field is too weak, it may not adequately coalesce water droplets, resulting in insufficient separation and oily water.

3. **High Viscosity Crude Oil**: The viscosity of crude oil significantly affects the desalting process. High viscosity can hinder the movement and coalescence of water droplets, leading to poor separation and oily wastewater.

4. **Presence of Stabilizing Agents**: Certain chemicals, such as surfactants present in crude oil, can stabilize emulsions, making them harder to break. This can result in more oil remaining in the wastewater.

Impact on Emulsion Treaters

Emulsion treaters are designed to separate oil from water in wastewater. When desalters produce oily water, it places an additional burden on these treaters. The increased oil content can lead to several issues:

- **Reduced Efficiency**: Emulsion treaters may struggle to manage the higher oil load, leading to reduced efficiency in separating oil from water.

- **Increased Chemical Usage**: To cope with the oily water, more demulsifiers and other chemicals may be required, increasing operational costs.

- **Potential Equipment Damage**: Excessive oil can cause fouling and damage to the emulsion treater equipment, leading to increased maintenance and downtime.

Solutions and Best Practices

Addressing the problem of oily water production by desalters requires a combination of measures:

1. **Optimize Desalter Conditions**: Regularly monitor and adjust the operating conditions, including temperature, pressure, and electric field strength, to ensure optimal performance.

2. **Use of Effective Demulsifiers**: Select appropriate demulsifiers tailored to the specific characteristics of the crude being processed. This can enhance emulsion breaking and improve separation efficiency.

3. **Regular Maintenance and Inspection**: Routine maintenance and inspection of desalter equipment can help identify and rectify issues before they lead to oily water production.

4. **Advanced Monitoring Systems**: Implement advanced monitoring systems to provide real-time data on separation efficiency and quickly detect when conditions deviate from optimal performance.

Conclusion

While desalters are a critical component of the oil refining process, their efficiency can be compromised, leading to the production of oily water that challenges emulsion treaters. By understanding the factors that contribute to this issue and implementing best practices, refineries can enhance the performance of their desalters and minimize the impact on emulsion treaters. Solutions such as optimizing operating conditions, using effective demulsifiers, and employing advanced monitoring systems can play a significant role in achieving this goal.