Choosing the right material

Choosing the correct type of scrubber construction material for the vessel and its components is the key to achieving a high service life of the equipment. At MACH Engineering, we can custom fabricate internals to meet the demands of your process. Learn more about how to choose a suitable material for your organization’s needs here.

The Importance of Choosing the Right Materials

20181018_115017_burnedSuitable materials can help avoid the extra time and costs associated with vent scrubber maintenance downtime. Improper selection of materials can lead to corrosion, deterioration, maintenance, downtime, regulatory noncompliance and fines. The right materials ensure your equipment lasts longer and works more efficiently for your operations.

Consider maintenance MACH conducted on a scrubber to illustrate this point. During the maintenance period of one of the vent scrubbers, MACH proposed to replace Monel Internals with the TEFLON™/PTFE Internals based on the process conditions.

Monel 400 is an amalgamation of nickel, copper and alloy. It is resistant to corrosion caused by acid, alkalis and seawater. Thus, it is widely used in the construction of environmental plants, where vessels and their components encounter acids such as sulfuric acid and hydrofluoric acid. However, its ability to withstand corrosion becomes limited in the realm of nitrous acid, nitric oxide, sulfur dioxide and hypochlorite. After scrutinizing the conditions of the MONEL internals, it became clear that MONEL did not serve well in the conditions present inside the tower.

20181018_115544Like Monel, PTFE also offers high chemical resistance but has fewer limitations. Moreover, PTFE offers greater thermal and mechanical resistance, and its properties maintain usefulness over a wide temperature range of -100 F to 400 F, which results in a high service life and low maintenance cost.

Along with internals, 12’’ MONTZ Structured Packing, previously installed in this scrubber, was replaced with 1’’ Tri-Packs in PFA. The latter is a type of random packing commonly used in mass transfer applications. 1’’ Tri-Packs is less expensive and offers similar low-pressure drop, compared to structured packing and a reasonable percent flooding based on the process data.


Tower Packing Media Selection

The right tower packing material will reduce the risk of leaks, structural damage and environmental risks. You’ll find various materials that can meet the specific needs of your organization’s vessel and ensure long-term operational reliability.

Common materials for scrubber construction and components include:


20181018_121522_burnedPolypropylene media can enhance the efficiency of the water treatment process. MACH polypropylene Hi-Rings are used in chemical, oil and gas, alkali chloride and environmental applications. They offer low specific gravity, high mechanical strength and large void space.

However, polypropylene might not withstand extreme temperatures or mechanical stress, making it crucial to get the proper construction material for your specific industrial process.


Ceramic is a thicker media than plastic, offering improved absorbing efficiency. The packing material can help reduce pressure drops when handling high liquid and gas flows. Ceramic saddles offer a wide surface area, improving mass transfer and efficiency at a lower price point.

Often, pre-fired ceramic bricks cover the organic linings in venturi throats. However, they can be brittle and shatter under mechanical stress, leading to unexpected downtime and safety concerns if not used correctly. Overall, ceramic materials are ideal in specialized applications for their resistance to high temperatures and certain aggressive chemicals.

Stainless Steel

Stainless steel components like trays, plates, fasteners and supports have been used in many absorbers due to their corrosion resistance and excellent performance in high-temperature applications. High chlorides can cause corrosion, and abrasion from the scrubber slurries can lead to wear failures. You’ll want to choose the right type of steel alloy, as the wrong one can result in corrosion or brittleness, leading to frequent maintenance and downtime.

Tower Internals Selection

Tower internals can provide uniform distribution to the packed bed while accounting for process considerations like fouling and foaming. MACH offers tower internals in various styles and materials, including:

  • Exotic alloys ceramic
  • Graphite
  • Plastics
  • Stainless steel

Using the right tower internals for your business’s specific application can help optimize performance in new or existing towers.

Structural Material Selection

Structured packing materials offer more efficiency and lower pressure drop than random packings or trays. MACH uses the following materials to construct wet scrubber systems:

  • Stainless steel
  • Titanium
  • Polypropylene/polyethylene
  • Fiberglass reinforced plastics


Contact MACH Engineering to Learn More About Designing Wet Scrubbers for Your Business Needs

While designing new systems or revamping less efficient separation units, it is imperative to carefully analyze your business’s process data and other requirements. A proper understanding of these specifications helps you pick the right equipment and the right material of construction to make high-performance units overall.

At MACH Engineering, we can design the products that best fit your operational needs. That way, your business can avoid downtime and its associated extra time, energy and costs.

To learn more about designing wet scrubbers for your facility, contact us today.