The fertilizer industry calls for different chemical process to manufacture different products. These processes generate gases and particulate matter during the process. Many of these processes could release toxins into the atmosphere. Gas cleaning is a common practice to attempt to eliminate these pollutants. Some of the primary purposes of gas cleaning are to recover raw materials, products, and byproducts. Other reasons are to follow guidelines for pollution emission standards set by the local, state, and federal governments and other regulatory agencies.
There are different types of gas cleaning in the form of wet and dry scrubbing. The type of scrubber that is appropriate will depend on the type and size of the particles and components of the gas present. When considering the technologies used to clean the gasses, design, and operation considerations are noted, such as handling characteristics, toxicity, and flammability. All of these will affect the operation of the scrubber. When choosing a scrubber manufacturer, it is important to keep in mind the experience that they offer. The cost of the unit and the budget.
There are several types of wet scrubbers that are common in the fertilizer industry. They are further classified as low, medium, and high energy scrubbers. Choosing a scrubber largely depends on the criteria for the air pollution problem in the fertilizer industry. The following will be taken into consideration, process, type of contaminants, separation efficiency and weather there will be a single-stage or various stages. The following are also very important, the packing type, pressure drop, liquid to gas ratio, temperature, maintenance, costs of installation, and the operation and performance history.
There are also different mechanisms of collection. In a wet scrubber, inertial impaction and interception are the main mechanisms of capturing particulate size particles (> 1 µm in size). Brownian diffusion is used for smaller particles. Larger particles are collected by inertial methods, where droplets will travel powered by inertia and then impact onto the media of the filter. When traveling at a lower momentum, the droplets will be intercepted by the filter media, this is called interception. Brownian diffusion is when sub-micron particles that contain very little mass follow the airstream then they unite until they form larger droplets that will be impacted or intercepted.
Once the scrubber is designed, it must be fitted with packing. Sometimes the packing is random or dumped, and other times it is custom designed. Packing can also be referred to as mist eliminators. It should be noted that not all mist eliminators are designed the same. There are many considerations when choosing a mist eliminator, the size of the droplets, liquid handling, pressure drop, and the compatibility of materials of construction. A properly designed mist eliminator will add many benefits to the process, such as improving product purity, reducing pollution, and reducing carryover, and protecting equipment.
Source: https://www.kimre.com/scrubbers-in-the-fertilizer-industry/
