Water Use in Paint and Coatings Processing
The paint and coatings industry has a major dependency on water use. However, water is a finite resource, and in many areas it’s also scarce.
Paint and coatings manufacturers use massive quantities of water as a major ingredient in the production of water-based paint products (solvent-based paints will not use water). In addition, when processing equipment and production lines are cleaned between batches, this typically results in large amounts of wastewater and excessive water consumption.
Unnecessary water use not only adds to the quantity of effluent and the cost of treating it, but also increases the wastage of heat, power and/or product in the effluent. In this way, paint and coatings processing and production can be extremely costly as well as have huge environmental impacts.
Solvent Use in Paint and Coatings Manufacture
As well as using excessive amounts of water, many paint and coatings manufacturers also use solvents in production and cleaning processes.
In solvent-based paint manufacture in particular, solvents are used for cleaning the transfer lines and equipment instead of water. The resulting waste consists of a mixture of solvent and paint.
Solvents can be extremely detrimental to health and the environment. Plus, they are extremely expensive to store, handle and dispose of. So, that’s why it’s important that paint and coatings manufacturers use the minimum amount of solvent necessary. However, in many cases, the operators like to be absolutely certain they have cleaned the line properly but, as a result, ‘overclean’ and then use much more solvent than is actually required for the cleaning process.
Reducing Water Usage and Meeting Sustainability Goals
Due to the problems associated with the disposal of paint wastewater and excessive water and solvent consumption, many manufacturers have focused their efforts on improving the sustainability of their production operations. Therefore, a key area that many companies are focusing on is water and solvent use.
One of the technologies increasingly being used by paint and coatings companies to reduce water consumption and solvent usage is liquid product recovery (“pigging”) technology.
Pigging systems recover residual liquid product from process pipes using a specialist projectile (called the ‘pig’). They deliver an extensive range of tangible benefits, provide significant cost savings and a high return on investment (ROI).
Where Can Pigging Systems be Implemented in Production Lines?
Typical examples of where pigging systems can be implemented in pipelines are:
- Transfer lines between process, holding, and dilution tanks
- Filling lines
- Where major raw materials such as solvents, resins and so on are transferred from storage vessels to process tanks
- Where raw materials are transferred to the weighing hopper.
In general, the longer the pipework and the larger the diameter, the more there is for paint manufacturers to gain from pigging regarding product recovery and water and solvent savings.
How do Pigging Systems Save Water in Water-Based Paint and Coatings Production?
Pigging technology can help companies that manufacture water-based paint and coatings reduce their water consumption and lower their environmental impacts by:
- Reducing the requirement for long, continuous water flushes when processing equipment and lines are cleaned between batches
- Preventing over flushing
Because pigging reduces the requirement for long and continuous water flushes, it saves considerable amounts of water. This is due to the HPS pig removing nearly all the residual product from the pipeline. HPS pigging systems have extremely high recovery rates and in most circumstances recover up to 99.5% of product from full pipelines.
Depending on the process or product, the high recovery rates of the HPS pig is sometimes enough to eliminate the need for water flushing completely. Even if water is still required for cleaning the pipe, the amount needed will be far less with a pigging process in place.
Pigging systems also prevent companies from ‘over flushing’ their pipelines. Because most pigging systems tend to be controlled automatically and their operations optimized, the chance of over flushing is significantly less.
Reduce Solvent-Use by Pigging
As well as helping paint manufacturers reduce water usage, pigging systems can also help to reduce solvent use during production processes.
Because the pig reclaims so much product from the line, the cleaning and changeover process is much faster (here’s a video of an HPS pigging system recovering product from a pipe).
So, as most of the product has been removed by pigging, it reduces the volume of solvent needed. In this way, the cost savings and environmental benefits from pigging are considerable.
The Dual-Pig System for Paint and Coatings
There are many different types of pipeline pigging systems. However, one of the most common pigging systems used by paint and coatings manufacturers is the dual-pig pigging system.
Not to be confused with the double-pig system, the dual-pig system was specially designed and engineered by HPS for paint and coatings applications. So, how do dual pig systems work?
The dual-pig system uses two separate pigs. The two pigs are introduced into the pipe with a smaller “slug” of either solvent or water between the two pigs.
The “product-pig-cleaning solution-pig” combination is propelled to the destination, recovering the product, and flushing the line with the water/solvent product that is between the two pigs.
How Do Dual Pig Systems Save Water?
Instead of long and continuous line flushing, a smaller slug of water or solvent between the pig is sent down the line.
By using two separate pigs, the dual-pig system offers dual cleaning capability while optimising the volume of solvent required to achieve pipe cleanliness. It also eliminates the need to use high volumes of water to evacuate the product residue from the pipeline and clean the pipe after each transfer.
So, because the use of water and solvent is more measurable, it can be controlled more precisely than standard flushing.
Other Benefits of Pigging for Paint and Coatings
As well as reducing water and solvent use, pigging systems for paints and coatings deliver a wide range of additional benefits. This includes reduced product cross-contamination risks, higher yields, faster cleaning and changeover times, and improved efficiency.
In addition, because HPS pigging systems have a high recovery efficiency, pigging inhibits the growth of harmful bacteria, ensures hygienic production, and reduces the risks of product spoilage.
With a pigging process in place, the same transfer pipeline can be used for different types and configurations of paint, instead of having dedicated lines for each product. The results in significant space savings, while increasing the flexibility and capacity of operations.
Importantly, by reducing waste, water use, cleaning chemicals, energy and other resources, pigging minimizes environmental risk in paint and coatings manufacturing plants.
Find Out More
From PPG, Akzo Nobel and Kelly-Moore Paints, to Ronseal, Benjamin Moore, and Sherwin-Williams, HPS pigging technology is trusted throughout the world.
If you are interested in a solution, then make sure you look at our savings calculator – It’s a quick and easy tool to estimate your pigging system cost savings.
Alternatively, to discuss reducing your water and solvent usage with our dual pig pigging systems, then please contact our process system experts today: