Overcoming four significant sealing challenges in chemical and petrochemical environments

Every process industry has specific challenges that are either unique to its line of business or shared by very few. Chemicals and petrochemicals are in that demographic.

Chemical and petrochemical plant operators work in unique environments, and their specialist work includes sealing hazardous fluids. As a result, maintaining safety and minimising emissions are mission-critical operational challenges.

The most common sealing challenges in petrochemical environments can be mitigated through the application of current technologies.

Challenge #1: Toxic and hazardous fluids

Chemical and petrochemical industry fluids can be characterised as either dangerous, toxic, carcinogenic, flammable, corrosive or any combination of these.

Common fluids in petrochemical processing include aromatics, benzene, toluene and xylene (BTX). Meanwhile, highly combustible Synthesis Gas (SynGas) is a hybrid of carbon monoxide and hydrogen, while olefins include ethylene, propylene, butadiene and butylene.

Consequently, mitigating the risk of emissions is crucial to plant operators, who require reliable and robust mechanical seals to ensure the risk to workers and the environment is minimised, if not eliminated altogether.

Dual O-ring pusher seals are used for fluids that are either low in temperature or specific gravity. They can operate reliably in flashing hydrocarbons. Typically, corrosive conditions demand robust materials of construction such as Alloy C-276 and Inconel.

Challenge #2: High pressures

The challenging environments within the chemical industry can stress sealing components, requiring exceptional resilience and precise design. Pumps with higher pressures, typically above 35 barg/500 psig, often require additional precautions, such as high-pressure sealing capability.

Similarly, applications with significant pressure and temperature fluctuations can impact mechanical seal performance. Examples of these high-pressure seals include the Type 8600, Type 48V and Type RREP.

Additionally, the spiral groove technology underpinning our Type 8628VL and Type 2800EX seals creates a gas film between the seal faces, supporting operation during pressure changes.

Challenge #3: HAPs and VOCs

Fluid processes within the chemical industry can involve emissions of hazardous air pollutants (HAPs) from industrial facilities.

Therefore, maximum achievable control technology (MACT) is often used to reduce fugitive emissions, such as when sealing volatile organic compounds (VOCs).

Dedicated John Crane products for sealing HAPs and VOCs

• A dual pressurised arrangement using John Crane Type 48 seals is an effective solution for reducing HAPs and VOCs.
• Our emission containment seal (ECS), Type 48SC or Type 48SCB serves as a backup to the primary seal by controlling emissions.
• This seal gas recovery system is a cost-effective solution for reducing VOC and other emissions, capturing and repurposing high-cost process gas.

Challenge #4: Temperatures (high and low)

Chemical processing is characterised by extreme pressures and temperatures. Our corrosion-resistant, edge-welded metal bellows seals, along with flexible carbon graphite secondary seals, such as our Type 609 (HTC) and 604 (HTC) double-ply seals, reliably seal applications at both extremes of temperatures.

How John Crane can help

Customers use our mechanical seals throughout the chemical and petrochemical industries on rotating equipment, including centrifugal and positive displacement pumps, as well as mixers and agitators.

By preventing the leakage of harmful liquids and fugitive emissions, they maintain efficient equipment operation and protect both individual operators and the wider environment. Our dual O-ring pusher seals are specified for a wide range of applications common to many petrochemical operators.

Supporting secondary containment

Our customers manage volatile materials in a risk-averse industry where primary seal leakage may need to be contained and controlled.

The John Crane range of dry gas non-contacting seals includes the Type 93FR separation seal. It can extend compressor life by inserting a nitrogen or air pressure barrier between the two segmented bushings.

Similarly, in a pump duty, if a primary seal fails, the patented, non-contacting, bi-directional seal face pattern on the Type 28SCB helps contain leakage.

Experts you can rely on

John Crane brings more than 100 years of engineering expertise to chemical industry applications. Our engineering experts can determine the most suitable seal for your specific application. Contact us and read more about our solutions for the chemical industry.