当应用程序暴露在严酷的酸d chemicals, your instrumentation needs to stand up to the effects. Substances such as hydrofluoric acid can create dangerous conditions and corrode certain materials, which could result in hazardous leaks.
How can you ensure you’re choosing the safest instrumentation for your acid application?
This article will discuss harsh acid applications and what types of pressure instruments can best handle these severe conditions.
Safety Concerns
While dangerous acids have been safely used in industrial applications for many years, specifying proper pressure instrumentation for these locations requires unique expertise.
Hydrogen Fluoride (HF) is used as a catalyst in the alkylation process - taking short-chain olefins (propylene/butylene) and combining with isobutane (all gasses) into larger molecules suitable for motor fuels. This “Alkylate” is used as a blending stock for high-octane gasolines.
There are a number of safety concerns to consider in acid applications: elevated temperature, leak paths and/or material compatibility of diaphragm seals.
When released in the atmosphere, HF rapidly forms dense vapor clouds that can cause severe burns and injuries to the eyes, nose, throat and respiratory system. Therefore, process containment is vital. You need instrumentation and equipment that can keep dangerous materials from escaping.
Acid Leak Detection
If your process experiences a leak, there isn’t much time to contain the acid. A visual warning can help you identify a problem and alert you to shut down your process immediately before anyone is injured.
Ashcroft has anAcid Lead Detection (ALD)assembly for these instances. It uses a special yellow coating that changes to red once it is exposed to acids with a pH of ≤ 3.0, providing a visual indication of a leak of process media.
Leak point(s) visually detected when acid encounters the sensing coating:
- top to lower housing weld
- diaphragm weld
- gauge to seal weld
- bourdon tube system leak
ALD also features a dual containment for safety and is available with pressure ranges to 10,000 psi.
It has an optional orange or yellow gauge case for identification and is available with Halocarbon® fill for oxidizing acids and silicone-freePLUS!™Performance. Learn more aboutALD in our brochure.
For other hazardous conditions such as elevated temperature or excessive pulsation, consider additional devices to help protect your instrument. These can be used in conjunction with the ALD design.
Material Selection
The materials you select for your instruments in acid applications must be able to withstand the harsh acid effects. There are a number of materials that aren’t compatible with the acids used in many applications. The material is especially important in diaphragm seals. Diaphragm seals by design are very thin. They have to be able to flex in order to provide enough displacement to drive the instrument.
A thicker material would be less sensitive. Because the seal is thin, it is more vulnerable to any type of harsh condition – including corrosion and pitting. It requires a reliably resistant material to prevent it from fracturing or in some cases permeation.
Stainless steel would corrode in acid. And while Monel offers acceptable resistance to HF, the gauge alone provides only single containment of the process media. A welded assembly would help prevent leak paths. Like metals need to be used when welding instruments, or accessories such as temperature dissipaters or snubbers and isolators together.
Hastelloy and Tantalum are strong materials that hold up well in HF Alky applications. If you need to identify what materials are best for your application, Ashcroft has aMaterial SelectorandCorrosion Guidefor your reference.
You can also use Ashcroft’s产品配置器to find the right instrument to meet your application’s requirements.
We don’t like to pressure you, but we have more information.
Now that you know the factors to consider when choosing the right pressure and temperature measurement instruments, you can research the best solution for your acid application.
Keeping these factors in mind can help you avoid equipment damage or operator injury and keep your process running, even in harsh chemical conditions.
If you want to learn more, read some of our other blogs:
- Choosing Measurement Instruments for the Chemical Industry
- Best Pressure Gauges for Ammonia Plant Applications
- Fill Fluid Options for Pressure Instruments
- When to Use a Welded Instrument Assembly
Feel free to contact us today totalk to one of our industry expertsand get your questions answered.
