NH3 Scrubbers: From Design to Operation – Materials, Costs, and Key Requirements

Author: Anna Frank, Equipment Selection Expert

One can never underestimate the impact of a livable, green environment as nothing can be put above the public health. Thus, factory premises and operations in the U.S. are regulated by the Environmental Protection Agency under the clean air act. One of the byproducts of modern industrialization to look out for is ammonium gases floating in the air. These do not fall into a hopper as easily as dust particles. Instead, what we need to do is strike them with a liquid so that they both bond together so that the ammonium can be disposed of and the cleaning agent can be reused again.

When it comes to the variety of scrubbers out there, there are a few main types of systems under which the liquid is introduced to the toxic gases requiring treatment. These are:

• foam scrubbers
• hollow scrubbers
• packed back scrubbers

The ideal choice when it comes to using a scrubber in the production of ammonia in particular is packed bed scrubbers. So that’s what we’ll be talking about. Because ammonium is a basic compound with a low pH, it needs to be neutralized. Water does a good job at this. Primarily, however, the agent used is different acids, such as:

• sulfuric acid
• hydrochloric acid
• phosphoric
• nitric
• acetic
• citric
• formic

Here’s why a packed bed scrubber is the way to go:

• High removal efficiency: owing to the large surface area for the gas and liquid to repeatedly contact on, the ammonia is absorbed. Assuming proper maintenance and design, 99% of ammonia is captured.
• A wide selection of scrubbing liquids to choose from based on the specific compounds produced on the premises. These acids react with ammonia to form stable ammonium salts which are easy to collect and sometimes even repurpose.
• Customizable design: this NH3 scrubber NAOH can be tailored to meet specific operational needs. They can be modified or set up with different packing materials, bed heights, and flow rates for best performance.
• Durability: ammonia scrubber manufacturers produce them from fiberglass-reinforced plastic or high-grade stainless steel, designed to withstand the corrosive ammonia environment.
• Compact: these do not take up a lot of space and since space is often limited in precious this is a godsend for a lot of factories.

Of course, not all environments are so simple that they simply release one single type of gas or debris into the environment. It may be that both acids and alkalis are produced. If that is the case, what we recommend is locating one NH3 wet scrubber behind the other.

In a packed bed scrubber produced by an ammonia scrubber factory, gas is directed inside the device and led into contact with acidic cleaning agents. These are in the form of packings, which are located in support distribution grids. The more that the gases collide with the packings, the more they bond with the reagent. Since the reagent is denser, the impurities are taken to the other end of the NH3 water scrubber and into a droplet eliminator. As a result, the newly cleaned air floats out the other end into the factory again or outside and the cleaning agent reenters circulation for further use.

There are different kinds of packings that scrubbers use.

In this case, stationary packings are used like activated carbon or structured ceramic media. The trajectory takes the case though them and doesn’t cause much wear and tear.

Torch-Air fixed bed scrubbers:

Materials are used that course throughout the section containing the cleaning agent. The aim in the case is to promote transfer of mass and minimize the risk of clogging. This movement generates turbulence and increases the number of surfaces that gas molecules can collide with. This requires the system to hold up throughout this boisterous process though.

Our floating packed bed devices, all vertical:

In this case, a variety of different shapes of light-weight materials are used for the packings. They are assembled in a chaotic way. Materials used include Pall rings and Raschig rings.

Our machines featuring random packing are:

Let’s take a look at one of the main determinants in acquiring a system – the ammonia scrubber price. First and foremost, let’s look at the construction materials that NH3 scrubber factory uses:

• Fiberglass-reinforced plastic: lightweight, corrosion-resistant, and cost-effective.
• If the temperature is low, polypropylene and PVC do well as they’re affordable.
• For high-temperature environments: grade 316L or duplex stainless steel or similar are the best choice.
• Exotic alloys: materials like hastelloy or titanium are used in extreme environments and come with a correspondingly higher cost from the NH3 scrubber supplier.

Other factors include the following:

1. System size and capacity: Larger systems designed to handle higher gas flow rates require bigger ammonia sample scrubber shells, more extensive packing material, and more robust recirculation systems, which increase costs.
2. Type and quantity of packing media: High-performance or custom packing materials for the most part costs more but provides better efficiency and longevity.
3. Automation and monitoring: Manual systems are less expensive but require higher labor costs for operation and maintenance. Automation, including real-time pH control, flow rate monitoring, and remote operation capabilities, increases the initial ammonia scrubber cost but reduces long-term operational costs and improves reliability.
4. Energy consumption: Systems designed to minimize pressure drops in the scrubber require less fan power, reducing energy costs. However, optimizing for low-pressure drops may increase initial NH3 scrubber design complexity and cost. Recirculation pumps must be appropriately sized to balance energy efficiency and operational effectiveness.
5. Installation: NH3 gas scrubbers requiring custom designs to fit specific site constraints or meet unique regulatory requirements can drive up costs.

A very important aspect of an NH3 scrubber is what it’s composed of as this will greatly impact how well it manages to consistently perform and how long it holds up. Some of the crucial factors to keep in mind in that respect are:

• The specific types of ammonia present on the site: different types will feature different hazards and more rigorous cleaning.
• Whether there is dust and additional acids to cleanse on the premises: these will require additional filters be installed in line with the ammonia gas scrubber.
• How much gas volume is actually being emitted.
• Corrosion resistance.

To ensure leak-proof operation, chemical-resistant sealants and gaskets are used, typically made from fluoropolymers like PTFE.

Additional NH3 scrubber media like rubber linings or epoxy coatings may be applied to enhance resistance to specific chemicals or abrasives.