Installing suitable pressure instruments and accessories for ammonia applications is crucial for the safety and success of your process. The pressure gauges and accessories you choose must be tough enough to withstand the corrosive and damaging environment of ammonia plants, or you risk equipment damage, operator injury, or costly downtime.
This article will discuss some factors you should consider when selecting pressure instrumentation for ammonia applications to ensure you make the best choice for your process. From pressure gauges and accessories to system design, we’ll cover the essential elements you need to consider to ensure safe and reliable operation.
Considerations when Selecting Pressure Instruments
When finding the right instruments for pressure measurements in ammonia applications, there are a few essential factors to keep in mind. From choosing a device suitable for the environment and process parameters to selecting one that can provide accurate results, it is necessary to ensure that you are selecting the best instruments for the job. To make sure you choose the suitable instruments for your application, consider these key considerations:
Instrumentation components must be able to withstand the corrosive effects of ammonia. Zinc, copper, and brass should not be brought into contact with ammonia-containing water, as corrosion can quickly occur. In addition, it is essential to be aware of materials affected by the Haber-Bosch process, which combines hydrogen and nitrogen to make ammonia. Glycerin is not compatible with nitrogen, so avoid any instruments containing glycerin.
Choose components made from 316 Stainless steel, carbon steel, or silicone for optimal protection. Additionally, solid-front gauges are an important safety measure as they can help protect operators from the potential danger of a burst gauge.
Liquid ammonia has an average temperature of -32 °F, so it is vital to ensure that any pressure instrument used is rated for that temperature. In addition, a capillary line should be used between the process and the instrument to offset the low-temperature conditions.
In ammonia production processes, steam is often utilized. Therefore, heat dissipation components like coil or pigtail siphons must be installed between the instrument and process to protect the instrumentation from the effects of steam. It is important to remember that, like any steam application, siphons must be primed during installation (water added to the lower half of the coil) to form a barrier between the direct steam and the wetted instrument parts. This will help prevent any damage caused by the steam.
Pulsation, Vibration, and Pressure Spike Effects
Vibration can cause the gauge needle to jump, making it hard to take accurate readings. Additionally, the effects of vibration can cause premature wear, reducing the gauge’s lifespan. A liquid-filled gauge can be used to minimize these issues, or the gauge can be relocated away from the vibration source. This will help to make readings more accurate and extend the life of the pressure gauge.
Adding liquid fill, such as glycerin or silicone oil, to a pressure gauge can enhance its performance and extend its service life. This liquid fill acts as a lubricant, dampening pointer motion and changing the resonant frequency of the gauge. With this liquid fill, the gauge will operate more smoothly and last longer.
In extreme conditions, mounting a gauge remotely and connecting it to the process with a flexible capillary line is a great way to keep it isolated from vibration sources. The capillary tube also functions as a flow restrictor, reducing the severity of pulsation. As a result, this setup offers a reliable and robust solution for measuring pressure in the most demanding conditions.
This innovative movement technology utilizes a thixotropic liquid that adheres to the pinion. As gauge pressure increases or decreases, the resulting shear load causes EDM molecules to scatter and the EDM material to thin at the layer being sheared. This action allows for a steady, flutter-free pointer, even in environments where vibration is present. The result is an accurate, accurate, and reliable gauge pointer.
When using a pressure gauge in an ammonia application, be aware of the potential for overpressure. Overpressure can deform the bourdon tube, causing a shift in the gauge’s calibration and creating excessive stress on the bourdon tube. This can lead to metal fatigue, the eventual failure of the bourdon tube, and the potential for loss of process containment.
To avoid these risks, selecting a pressure gauge with an operating pressure of 50% of its full-scale pressure is recommended by ASME B40.100. In addition, typical operating pressures for a gauge should be confined to 25-75% of its full scale. Taking these precautions can help you ensure the safety of your pressure gauge and minimize the risk of overpressure.
BCST Pressure Gauge
BCST has 21 years of experience manufacturing pressure gauges, offering unmatched quality control from raw materials to the finished product. With a wide range of configurations available, BCST pressure gauges are perfect for nearly every industry, assuring you that you have the right product for your specific process. In addition, our fast delivery and abundant raw material stock ensure you always get your product when you need it. Plus, when you choose BCST, you get the added benefit of OEM design services. All this makes BCST the ideal one-stop solution for reliable and quality pressure gauges.