Fouling is the deposition and accumulation of undesirable materials such as scale, algae, suspended solids and insoluble salts on the internal or external surfaces of processing equipment, such as heat exchangers. Heat Exchangers are process equipment in which heat is continuously transferred from a hot to a cold fluid directly through a heat transfer surface that separates the two fluids, such as a plate or tube.
Selecting the correct gasket material is vital to the effective operation of the plate heat exchanger. The majority of PHE gaskets are manufactured from rubber polymers, requiring replacement when the gasket loses its ability to seal due to hardening, loss of compression set and deterioration.
The welded (BLOC) plate heat exchangers contain more robust plates with greater thickness and do not have standard PHE rubber gaskets. This different design allows higher temperature and pressure ranges. Compact in design, they still pack a punch with outstanding heat transfer coefficients, even under the most stringent applications. Heat Exchangers WA provide servicing of welded (BLOC) plate heat exchangers, having serviced several COMPA-BLOC from mineral processing plants.
HEWA’s purpose built 4000 m2 workshop offers drive-in and out delivery with 32 & 10 tonne gantry cranes to allow easy lifting and improved service efficiency. Our trained technicians provide a range of tooling competency to remove the welded plate (BLOC) heat exchanger nuts and side panels.
After assessment of blockages, the welded core is lifted for cleaning in the 17,000 L chemical static baths and high pressure wash bay. Simultaneously, the port liners on the side panels are integrity tested via red dye and structurally repaired if required.
Following cleaning and port liner repair, the welded core is assessed before reassembling the BLOC and hydro testing. Upon completion of the service, the welded (BLOC) plate heat exchanger is dispatched and the client provided with a comprehensive report detailing the extent of the service. Heat Exchangers WA have been continuously working toward improving the efficiency with which we service BLOC’s, having reduced the required man hours by over 50%.
The Pilbara region is a beautiful part of North West Australia, where red earth and deep rocky canyons contrast the dazzling white beaches and untouched coral gardens. The Pilbara is commonly referred to as the ‘engine room’ of Australia, home to a massive mining and processing industry of crude oil, natural gas, iron ore and salt. The climate can be harsh and the heat scorching, with an annual average high temperature of 32 °C. Due to the high ambient temperature year round, it is crucial that the cooling tower equipment operates at peak efficiency to sustain the throughput and revenue of processing plants.
Heat Exchangers WA just completed the delivery and installation of an Evapco induced draft ESWA Closed Circuit Cooler at the largest liquid nitrogen, oxygen and argon production facility in the Pilbara. The nine less efficient existing adiabatic coolers with a spatial footprint of 141.75 m2 were replaced with a single water cooled Evapco ESWA cooler with a spatial footprint of 30.75 m2. Effectively, the water cooled Evapco ESWA cooler requires just over a fifth of the space to achieve the same required 3700 kW total heat rejection.
The Evapco ESWA design combines low sound and low energy consuming axial fans with high performance counter flow heat exchange. The total power consumption of the single Evapco unit is 45 kW, compared with the 207 kW of the nine existing adiabatic coolers, saving the client nearly $100 000 in annual power consumption costs, based on the processing plants operational data.
Furthermore, the water cooled Evapco ESWA cooler reduces the outlet water temperature from the original 35 °C to a new decreased 32 °C. Colder temperatures help the gas compressors to run for longer periods without overheating, effectively augmenting the plant’s production by roughly 2-3 tonnes per year. An additional benefit of the colder cooling water is the extension in lifetime of processing equipment.
Does your current cooling tower equipment have outdated power consumption? Are your plants operational and maintenance costs excessive? Upgrading your cooling tower equipment can save you substantial annual electricity consumption costs, improve process efficiency and increase production output. Here at Heat Exchangers WA we pride ourselves on exceptional service and commitment to the client, our cooling tower division designs each product to meet your required specifications the most effective and efficient way possible.
Welcoming in the beginning of 2017 is the completion of Heat Exchangers WA’s annual customer satisfaction survey. Heat Exchangers WA received feedback from fifty of our 2016 customers in order to achieve an increased understanding of the market response to our service, quality and price. The customer satisfaction survey is a tool we use for continuous improvement, with the feedback providing valuable information on how we can continue to be the best in the industry.
Heat Exchangers WA were thrilled to receive a score of 8.64 for service, aligning closely with the company mission statement “Service is Our Passion”. Additionally, attaining a score of 8.48 for quality portrays the high standard we hold ourselves and suppliers to, such as Evapco and Kelvion. Finally, achieving a score of 7.80 for price shows we are well placed against competitors, providing excellent service and quality at a competitive price.
An overall value score of 8.31 out of 10 solidifies our position as a market leader in the field of heat transfer equipment supply and service.
Not only did we receive great scores across all three categories, but also gathered an overwhelming response in extra feedback, with testimonials such as:
“Perfect. We call up and anything we want is handled with great, efficient timing. The team goes above and beyond to deliver the best results” – Project Manager, Aromatic Oil Company
“Excellent across the board, with a large quantity of essential parts on hand, and a product that lasts a good amount of time” – Warehouse Supervisor, Public Transport Company
“Incredibly happy with the level of service and quality of product offered at a competitive price, we will continue to utilise you for future business” – Maintenance Engineer, Chemical and Mineral Processing Company
“HEWA have always been able to deliver as required with prompt and professional service. From experience, HEWA are known to be price competitive.” – Process Engineer, Minerals Processing Company
An enormous thank you to all clients who participated in our customer satisfaction survey. We value all business from our clients and with their feedback we hope to continuously advance our service, quality and price.
Written by Chris Haslego – Virginia Heat Transfer
Plate heat exchangers are extremely efficient and can be workhorses in many different types of environments. But, knowing what to watch for when inspecting and maintaining your plate heat exchanger is critical. We’ll explore five common questions and answers to help you take better care of your plate heat exchanger.
1. How can I tell if my gaskets are glued or utilise a glue-less style attachment method?
There are two (2) main types of attachment methods for gaskets on plate heat exchangers. Viewing the plate pack from the side during operation can give you insight into the attachment method used. First, let’s explore the glued type of gaskets. The glue used for the gaskets comes in two (2) main types: rubber based and epoxy adhesives. Rubber type adhesives are designed to essentially hold the gaskets in place while the units are tightened. In lower temperature duties, this glue may be able to hold a firm bond over time. In higher temperature environments, this style adhesive will likely require repair when the unit is opened. Epoxy style glue is meant to perform as a far more permanent bond for duties where the heat exchanger may need to be opened frequently for cleaning. Rubber based adhesives can be field removed for a gasket change out (although it isn’t generally recommended for an entire plate pack) while gaskets applied with epoxy adhesives usually have to be frozen off with liquid nitrogen in order to change the gaskets. So, if you’ve determined that your heat exchanger has glued gaskets, it’s important to determine which type of adhesive was used. Glueless systems utilize a physical attachment method to hold the gaskets onto the plates. There are three (3) types of common glueless attachment systems: clip-on, snap-in, and “push” on. Viewing the the side of the plate pack, a clip on style gaskets will present like this:
Notice the clips that “grab” onto the edge of the plates. These are easy to spot. These type of gaskets are favored on newer model plate heat exchangers. The snap-in style gasket looks a little different:
Notice how the plate has small holes punched near the edge and the gasket has a small nipple that passes through the hole for attachment. This method was utilized more on older plate heat exchangers. In a photo presented below in Question #2, you can see a side view of this type of gasket. There is a third variety that we refer to as “push” on. Push on gaskets have various crimped area around the gasket groove and the gaskets are “pushed” into the crimps to hold the gasket in place. This type of gasket attachment is difficult to work with and isn’t as widely used as the others. Also, these gaskets will present just like glued gaskets from a side view of the plate pack.
2. Why are my plates crooked when I hang them in the heat exchanger?
Remember, it’s the thin plates inside your heat plate exchanger that make it work so well. Typically, these plates range in thickness from 0.40 mm to 0.60 mm (although they can be thicker). Some manufacturers will reinforce the areas of the plates where they contact the upper and lower bars in the heat exchanger. If these areas are NOT reinforced, the plates can bend in these areas and cause serious misalignment issues. Here is a view of the hanger areas of some plates that have been seriously compromised:
Without proper alignment at the top and bottom, the plates are able to move from side to side and up and down during the tightening process. This results in gaskets misalignment and often times leaks:
If you notice any of your hanger areas are bent, try to straighten them as best you can before reinstalling your plates back into your unit. To avoid bending your hanger area, it’s always a good idea to use a lubricate compatible with your process on the top and bottom bars when removing or inserting plates into your heat exchanger.
3. How can I tell if my plates have holes in them?
This is a common question that we receive. While some folks have constant process measurements that would immediately notify them of a cross contamination, in other applications, the engineer may not be aware that the hot and cold fluids are mixing. If you suspect that your plate heat exchanger may be leaking hot fluid into the cold circuit or vice versa, there is a relatively simply way to find out. Isolate and drain either the hot or cold circuit on the plate heat exchanger. After this circuit is drained, if the drain is nearby the bottom piping leaving the heat exchanger, simply leave the drain open. If the drain is far away from the heat exchanger or if you have a spool installed on the bottom of the drained circuit, you could just remove the spool for visual access. Now pressurize the opposite side and watch the drain or look into the open port at the bottom of the heat exchanger. If you see process fluid, you’ll know that at least some of your plates have holes in them and it’s likely that all of your plates have reached the end of their useful service life.
4. What is the difference between fouling and scaling?
This is a common point of confusion for plate heat exchanger owners. Fouling is a term typically used to refer to physical build up on the plates that can be easily hydroblasted or brushed off the plate surface. The most common source of fouling is biological growth from a cooling tower. Scaling is the term typically used to refer to a hard mineral build up on the surface of the plates that usually has to be removed via chemical cleaning of the plates. The most common culprits are calcium-based salts at elevated temperature.
5. What should I do to monitor the overall health of my plate heat exchanger?
First, it’s important to have a baseline performance from when your unit is either brand new or freshly cleaned. Don’t rely on the design data sheet from the factory. Variances in flows and temperature from design to operation are a virtual certainty. If you don’t have temperature and pressure gauges on the inlets and outlets of your plate heat exchanger, install them during the next outage. Record these reading when your plate heat exchanger is at a known clean stage and you’re operating at a point where you expect to run most of the time.
Now, you can monitor your plate heat exchanger for variances from these baseline readings. Any increase in pressure drop or loss of heat transfer can indicate that your heat exchanger may need cleaned.
Also, at least once a year, inspect the side of the plate pack and look under the unit for any leaks. Inspecting the sides of the gaskets can help you catch cracks that are developing due to oxidation before they become a problem.
These gaskets are very near the end of their lifetime. A quick inspection shows us this and we can plan for it during the next outage.
For more information on maintaining your heat exchanger read our other article, ‘Maintain Your Heat Exchanger to Maintain Your Bottom Line‘. Alternatively, feel free to contact us directly at Heat Exchangers WA on (08) 9350 8500.
Are you experiencing reduced heat transfer efficiency that is costing you through reduced output or increased energy cost? A range of problems can lead to poor performance or failure of your plate heat exchangers. The four most common plate heat exchanger problems that occur are:
- Fouling- leads to reduced heat transfer and potentially higher energy costs
- Blockage- leads to reduced heat transfer and potentially higher energy costs, increased fluid velocity leading to potential erosion problems
- External leakage- leads to wasted product and potentially dangerous spills
- Internal Leakage- leads to cross contamination of the fluids
Typically, plate heat exchanger performance issues can be remedied by servicing the heat exchanger to bring it back to its original design capacity. An analysis of the plate heat exchanger should be conducted in order to assess the problem and determine its solution as quickly as possible. This is important as problems can escalate if left unattended.
Fouling deposition comes in many forms such as settlement of particulates, biological deposits, decomposition and crystallisation. Fouling is heavily dependent upon the process fluid, operating conditions and overall design of the heat exchanger. Fouling reduces the heat transfer between fluids, impedes fluid flow, increases pressure drop and impacts upon the overall efficiency of the heat exchanger and attached systems. It is crucial to determine the type of fouling and its mechanism to provide adequate mitigation strategies. Biological fouling and settlement of particulates can typically be reduced by improving filtration upstream. Other forms of fouling can be reduced at times by altering fluid velocities or upgrading the process heat exchangers to one with optimised designs and superior temperature control.
Partial blockages result in non-uniform flow over the heat exchanger plate affecting heat transfer and increasing velocities, which can result in increased erosion rates. Leakage can occur through port liners allowing fluid to come in contact with the frame plate. In this situation the frame plate can corrode resulting in a more expensive repair.
The cross-contamination of fluids occurs due to the perforation of a plate within the heat exchanger. This worst case scenario is uncommon, however, it can occur due to an aggressive chemical or long periods of operation at high temperatures/pressures. The cross-contamination of fluids will be difficult to detect as the heat exchanger will not leak externally. It is therefore important to be aware of the condition of the process fluids to detect an internal leak. Internal leakage can be minimised by the selection of the most appropriate plate material for the conditions in the heat exchanger. Perforated plates are detected during servicing or by hydrostatic or gas testing.
Heat Exchanger inefficiency or failure can be overcome by the implementation of an appropriate maintenance strategy. The cost of failure or inefficiency can be many times the cost of servicing when additional energy costs and lost productivity, particularly in the event of an unplanned shutdown of your plant are considered.
[caption id="attachment_1633" align="aligncenter" width="624"] Completed Service of Plate Heat Exchanger[/caption]
Optimisation is a crucial aspect of the role of an engineer whereby design constraints and criteria are assessed via a systematic process in order to provide the maximum achievable value. An aromatic oil processing company approached Heat Exchangers WA a short time ago with cooling tower inefficiency and heat exchanger fouling problems. Since then our cooling tower and plate heat exchanger divisions have been working in a team closely with the client to not only provide the required heat transfer but additionally assist in optimising the design and processing functionality of the plant. Additionally, our engineers designed the entire plant heat rejection system, which involved a network of cooling towers and plate heat exchangers to cooling and condense process steam before cooling water to a final workable temperature. Your calls for help are what drive us, service is our passion. We just happen to sell great heat exchangers.
A total of twelve gasketed plate heat exchangers have been supplied to the client with a further two currently being assembled to allow for the client to increase their production capacity. The heat exchangers are designed with stainless steel (316 L) plates and Viton gaskets (Gaskets that are phthalate free in order to prevent it from being absorbed into the oil). Furthermore, three MTT Evapco cooling towers replaced less efficient towers in order to meet the required cooling whilst providing ultimate corrosion protection due to its fibreglass construction material. The production of aromatic oils can unfortunately produce severe scaling with a potential for blockage, therefore Heat Exchangers WA provide regular servicing as an effective preventative measure to various operating aromatic oil production plants throughout Western Australia.
Heat Exchangers WA in conjunction with the Triple M Group have supplied the air-conditioning process equipment at the expansive Capital Square development in Perth City for Woodside Energy. The Capital Square development was a monumental contract for Heat Exchangers WA in terms of the package size containing both Plate Heat Exchangers and Cooling Towers that were delivered to the client. Furthermore, the equipment was fitted in a mid-level plant room increasing design and installation complexity, requiring Heat Exchangers WA to not only provide the required heating and cooling capacity but also adhere to the architecturally aesthetic preferences.
Within multi-storey buildings the number of floors relates to the lettable space available and as a result the overall profit of the landlord. Cooling towers are of immense height, therefore, reducing the number of floors that can be constructed. A low profile forced draft Evapco cooling tower was selected, effectively decreasing the height of the tower from 4.5m to 2.7m and thereby its impact upon the number of floors that can be constructed. Our sales engineers ensure that the client is delivered the most effective and efficient cooling solution required in order to increase the rate of return.
A total of eight Evapco LPT forced draft cooling towers were delivered to the Capital square development. Additionally, eight sizeable Gasketed Plate Heat Exchangers were provided in order to deliver a total of 9000 kW at 1°C LMTD thereby allowing maximum heat transfer area. Gasketed Plate Heat Exchangers were utilised to enable heat transfer whilst preventing cross-contamination by separating the water from the chiller and cooling towers. This separation is crucially important due to the exposure of water running through to the cooling towers to the ambient, which can cause fouling and scaling to occur within the chiller process equipment.
It is a beautiful sunny winter’s day here in WA! Heat Exchangers WA just replaced another older forced draft condenser with a sparkling brand new Evapco CATC induced draft Evaporative Condenser. This included all the bells and whistles, such as Thermal-Pak II Coil, superior efficiency drift eliminators and the patented motor swing out arm plus davit providing unprecedented maintenance access and inherently better operation. Additionally, the Evapco condensers arrive pre-built allowing the minimisation of your on-site assembly costs.
Are you aware that by installing a newer model condenser you can save significantly on electricity costs and reduce environmental impact?
One of our food processing clients saved the equivalent of 5 household’s annual electricity consumption! By replacing their older, less efficient condenser with a new 11 kW Evapco CATC induced draft Evaporative Condenser they were able to achieve the same required output at a far cheaper cost, saving both their money and our environment.
Is your current heating and cooling equipment getting a little tired and as a result has an out-dated power consumption? Is it costing you unwanted operational and maintenance costs? It could be time for an upgrade. Here at Heat Exchangers WA we pride ourselves on exceptional service and commitment to the client, our cooling tower division designs each product to meet your required specifications the most effective and efficient way possible. Just ask our food processing client, they loved their first Evapco condenser so much they wanted two more, hopefully we can connect four!