Emissions are a big deal, challenging companies as they strive to adhere to ever-increasing regulations. Add in profit expectations, aging equipment and public perception, and this is a perfect storm that plant maintenance managers must address.
While this might sound all doom and gloom, the good news is that technological advances have brought very real solutions to fighting the emissions battle.
Let’s first look at what a proactive approach to valve and flange emissions can offer. Plants not only have a moral obligation to prevent unnecessary emissions, but a failure to do so puts them at a major financial disadvantage compared to others.
Striving for successful management has the potential to:
- Increase plant reliability
- Increase worker safety
- Benefit the environment
- Limit gas wastage
- Prevent gas leakage
- Lower running costs/reduced ownership costs
However, achieving these aims can only be reached if we first understand the reasons for excessive leaks in the first place. Valves are one of the greatest culprits, responsible for around 50%-60% of fugitive leaks. The reason for this is simple—the seals lack integrity.
While valve packing and gland follower bolts have a finite lifespan, the key to reducing emissions doesn’t lie within increasing the seals’ force (although this has some bearing) or investing in upgrading them. Instead, it lies in using advanced packing materials and the correct lubrication and gland force.
Low E valves, in particular, are often seen as the problem child within the gas pipe system. Unless packing is cut correctly, the rings are optimally installed within the stuffing box, and the bolts are lubricated and then tightened correctly, leaks will continue to occur. While small leaking valves are often replaced when they fail, larger valves need more cost-effective maintenance solutions.
Enter the optimal 4-point plan for effectively reducing gas pipeline emissions.
1: Identify the Issues
In older valves and pipelines, leaks are usually down to a combination of reasons. These include:
- Deep stuffing boxes that cause excessive friction. They’re so commonplace because it used to be (incorrectly) thought that they provided a better seal. Unfortunately, we now know this is problematic, creating an
environment that causes excessive packing relaxation and high stem friction.
- Poor gland force on the packing set from the gland bolts or studs
- The improper lubrication. Poorly or wrongly greased bolts, studs and nuts are major reasons behind excessive leaks.
- Loss of gland force is usually caused by packing relaxation, thermal cycling, wear, pressure surging, extrusion, poor packing installation or a combination of these.
- Poor packing composition prevents the valves from sealing correctly. This often occurs when a galvanic reaction occurs between the valve stem and the packing itself, causing pitting corrosion.
2: Select Advanced Packing Products
Today’s technology brings solutions that address many of these issues. From valve type-specific packing through to control valve kits, bushing, K-factor co-efficient lubrication and Live Loading Disc Springs, we can dramatically reduce emissions and increase the effectiveness of packing over a longer term.
3: Commit to Best Practice Maintenance
Quality valve maintenance has become easier to address over the past decade. This is largely due to the increase in enforced legislation that’s meant strategic research and investment have had to be channelled into advancing technology.
Despite this, there’s still a legacy of acceptance that gas leaks from valves are inevitable and that definitive work to correct this is expensive and ongoing. This is now far from the truth. Reliable, value-for-money packing kits are readily available, meaning that maintenance teams can easily overcome many of the historical issues of correcting leaking valves.
Best maintenance practices include:
- Correctly cut packing rings. This means either having the know-how to correctly cut them yourself or purchasing Low E Valve packing pre-cut to size.
- Correct installation of packing into the stuffing box. Getting this right is essential to reducing emissions.
- Tightening bolds and lubrication. The right lubrication must be used, and the correct gland load must be applied to ensure a good seal.
- Consolidate the packing. This crucial final step is the most overlooked, and a failure to carry this out will likely lead to poor sealing and further leaks.
4: Follow a Proactive Maintenance Approach
Failing to reduce leaks and emissions leads to potential fines and higher running costs and harms the environment. Today’s technology means companies are no longer required to make major investments to or exceed emissions legislation.
Products such as the Chesterton 5150 Live Loading Disc Springs allow maintenance engineers to easily address valve leaks caused by pressure surges, thermal cycling, packing relaxation, extrusion or wear on various valves. Such technology provides more stored gland load and lifespan.
Proactively using technology such as this, rather than waiting until valves and packing corrode to failure, provides cost-effective and simplistic ways of meeting obligatory maintenance requirements.
The 5150 Live Loading Disc Springs is only one example of the advances made to help control unnecessary emissions.
5: Download our Tech Tips to Seal Low E Valves
Discover more by downloading the Chesterton eBook “Tech Tips to Seal Low E Valves“. You will learn:
- How to cut packing correctly
- How to install packing rings into the stuffing box
- Best practices for bolt tightening and lubrication
- How to tighten and consolidate valve packing
…and take the next step to plant emission correction today.
This article was featured in Utility Magazine