Plate heat exchangers regeneration step-by-step

During this time of the year we usually receive many service and maintenance requests for the complete regeneration and revamping of plate heat exchangers. In this case, inspectable type heat exchangers offer the possibility to be opened to proceed with washing and cleaning operations and the inspection of all the parts, in addition to the possibility of an upgrade of the thermal performances.

Let’s then see step-by-step all of the operations we usually do during a heat exchanger regeneration servicing, aimed to restore the efficiency of the exchanger as if it was new.

Very often heat exchangers that come for a revamping are in quite disastrous conditions, after years of functioning. First of all, we open the exchanger in order to inspect the wear status of tie-rods, port linings and gaskets. While doing a complete regeneration of exchangers, we usually suggest customers a complete replacement of the gaskets with a full kit of brand new ones, even if the operation is expensive and invasive, but it is suitable while doing the washing of the plates.

Another operation we usually do, once the plates have been washed and cleaned, is to undergo plates at 100% with an integrity testing using penetrating liquids. It allows to ensure that plates have no micro-holes or hairlines cracks. These could be caused by corrosion, revealing a serious problem of incompatibility of the fluids with the construction material of the plates, or even due to erosion or engendered by a wrong tightening made by the end user. Once the exchanger is reassembled it is indeed complicated to search for possible leaks or mixing.

 

And so, washing of plates, penetrating liquids test and potential discharge of damaged plates. These operations allow to understand if there is any issue of compatibility between the fluids circulating within the exchanger and the material of the plates, alerting the customer.

The exchanger is then re-gasketed, using brand new gaskets, and also potentially damaged port lining – in case of flanged exchangers – and threaded connection ports are replaced. The exchanger is then reassembled, with the attention of replacing the tie-rods, or at least to clean the existing ones. The exchanger gets tightened with the right level, and undergoes a pressure test, aimed to ensure that the two circuits are correctly sealed with no leaks within the exchanger.

Once the pressure test is completed, the plate heat exchanger is ready to be dispatched to the customer. A new label is placed, reporting the date of the revision and complete with all the codes that identify the provided operations.

At last, a further operation we usually offer is to ask the customer if he needs to upgrade the performances of the exchanger in order to meet new requirements of his plant. Is it possible indeed to expand the exchanger, or to make some variations to the design of the plates, giving in fact a brand new life to the plate heat exchanger.

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Revamping in temperature regulation of life science reactors

Happy New Year and a good start 2021 to everyone!
During this past Christmas holidays pause, in Tempco we’ve fulfilled a revamping intervention on the interfacing heat exchanger employed for the temperature regulation of reactors in the production plant of a customer in the life science and pharma sector.

Tempco revamping scambiatori pharma

The customer contacted us after more than 15 years of non-stop operations of the plate heat exchanger, contributing to the correct temperature regulation in the production of APIs. The intervention involved the complete regeneration as new of the plates in the heat exchanger.

piastre scambiatori di calore revamping

In addition, in order to fit the new production needs of the customer, we’ve also ensured an increase of the thermal exchange surface of the heat exchanger, which in this kind of thermal machine is possible by simply adding further plates to the exchanger.

Tempco revamping scambiatore pharma

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Happy Holidays and a Happy 2021 from Tempco

This 2020 is turning to an end, and every year during this period we are committed to find a special phrase for an emotional email, to be sent to a list of people who collaborated and collaborate with us.

This year I wanted to do something different. I thought about making a video, similar to the ones we are currently using to maintain our social relations.

While preparing this video, I asked myself what this New 2021 will bring to us. And I’m sure there will be a huge increase in artificial intelligence applications, employed for control and monitoring of industrial plants. Everyone speaks about Industry 4.0, but in the utilities sector, in which Tempco operates, this is something that still struggles taking off.

Well, I believe that in 2021 we will see an increase in these applications, for the control and monitoring of performances of industrial plants, with a fundamental goal, the smart management of energy. I do believe there will be a growth in smart monitoring systems that allow to use energy only when it is necessary, and only in the right amount that is needed.

I believe this could be our mission for the New Year.
I wish you all then a Happy Holidays Season and a Happy 2021!

Grosjean crash, when temperature control makes the safety

The accident occurred to Grosjean in a recent Formula 1 Grand Prix prompted me for an interesting more in-depth reading. Eventually also related to the relevance of the control of temperatures required for the manufacturing of today’s safety fiber carbon structures.

Looking at the pictures of the fiber carbon car body after the accident, I suddenly remembered some older accidents that involved in the past other drivers such as Ronnie Peterson in Monza, or also Ayrton Senna and Alex Zanardi. Sadly deployed in really much more serious consequences compared to Grosjean, who will be probably able yet to participate at the next Grand Prix.

A very huge step forward in the safety within F1 is of course due to the driver crash-protection system (Halo) employed in today’s cars, which offers an extreme toughness. So I stumbled upon a very interesting interview to the AD of Dallara, the company that has the exclusive for the manufacturing of carbon fiber chassis of Formula Indy. In the video the AD explains how each and every single carbon fiber ensures the dissipation of energy generated by a possible accident, that otherwise would be discharged directly on the driver, causing fractures and damages to internal organs too.

Then I’ve realized that, with our small contribution, in Tempco we also do our part because we supplied a cooling and fine temperature regulation of furnaces employed for the processing of carbon fiber structures. The application required the thermoregulation and cooling of the furnace, in order to avoid temperatures to exceed upper limit levels.

This is a kind of cooling toward the bottom, then similar to another application we deployed for the cooling and fine thermoregulation of furnaces employed for the production of carbon ceramic brakes, also employed in high-performance cars and airplanes. A crucial step in the production of these special brakes, both for preparing them to further mechanical processing and to guarantee the high mechanical characteristics that define their perfect functionality.

Near-cryogenic cooling in pharma production

Delivery of a second refrigeration unit for extremely low temperatures for a Swiss customer operating in the pharma sector. The application involves the cooling of pharma reactors employed for the production of APIs, requiring cooling at near-cryogenic temperatures, -25° C. The new plant has been supplied following the success of a first installation made a couple of years ago at the same customer’s facility.

Tempco chiller cryogenic cooling

 

The customer increased indeed by 50% the production capacity of the pilot line, and thus asked us to increase its overall capacity with an additional similar solution, offering half the cooling capacity.

This is therefore a solution employing air condensed chillers, able to achieve cooling at temperatures of -30° C. Full stainless steel execution with special insulation suitable for extremely low temperatures. Automatic condensate regulation in order ensure maximum efficiency and availability through the whole year, avoiding the risk of unwanted downtimes.

Tempco raffreddamento pharma

 

We’ve accepted the challenge and fulfilled the request, even though respecting the limitations imposed by the current regulations on refrigerant gases.

Tempco chiller pharma

tempco cryogenic cooling pharma

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How to control electric heaters in thermoregulating units?

Which are the possible solutions to control and manage electric heaters employed in thermoregulating units? There are in fact three possible options, offering a more and more fine and accurate control of temperatures.

The first option for the control of electric heaters in thermoregulation is to use an electronic thermoregulator, that ensure the fine regulation of the temperature set-point by commanding a contactor, hence electric resistors, with a certain frequency. Clearly, if the resistors have a high frequency of intervention, especially in case of high power resistors, the service life of the contactor will be limited.

Contacts in a contactor are indeed designed to ensure a certain operating life, with a number of cycles, and beyond it the contacts get damaged. It happens that contacts get welded together inside the contactor, so that they don’t respond anymore to the thermoregulator, pushing the thermoregulating unit up to excessive high temperatures.

There are obviously some safety systems, such as safety thermostats, that provide the interruption of power and then halting the system. In this first option, thermoregulation has then some physical limitations, due to the maximum number of intervention allowed by the electro-mechanical contactor.

 

 

A second option is to employ a static relay, which is electronically managed avoiding electro-mechanical contacts. This solutions also enables to operate micro-openings and micro-closings, achieving a more fine and sophisticated temperature regulation.
Anyway, even a static relay can get damaged and thus remaining in a closed status, pushing the thermoregulating unit over the maximum safety temperature. Also in this case, the safety thermostat will operate, and usually in our Tempco thermoregulating units we implement a line contactor managed by the safety thermostat, providing the safety halting of the system when maximum temperatures allowed are exceeded.

At last, a third option is to employ a SCR (silicon controlled rectifier) static relay, with power adjustment. These device allows an even more fine and precise control of the temperatures. Instead of working with on-off activation of the thermoregulator, an SCR allows indeed a modulation of power supply, from a minimum value up to a maximum temperature value. Exactly as if it was an inverter, but applied to electric heaters.

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Thermal energy management guide Tempco is online

The strong and consolidated expertise of Tempco in the field of thermal energy management led a few years ago to the making of a book called ‘Thermal energy and industrial processes’, which is now being released also in English and made it available in a dedicated section of the Tempco website.

We have indeed decided to make these resources available online, in order to help operators and companies navigate through all the thermal machines available on the market, as well as getting more familiar with some essential concepts such as the evaluation of the thermal duty, a fundamental step for the correct engineering of temperature regulation, heating and cooling systems.

The main section of the technical manual is focused on the definition of the several types of thermal machines existing, and how to select the right one based on one’s individual production requirements. From classical heat exchangers, evaporative towers and chillers through thermoregulating units equipped with the most advanced IoT condition monitoring solutions, and up to smart systems aimed to further increase energy saving leveraging free cooler and dry cooler.

The manual finally includes a section offering a wide range of industrial applications realized by Tempco over the years, within a great variety of industrial sectors such as pharma, chemical and food & beverage, oil & gas, steel mill and machine tools, automotive industry, cogeneration and power generation, and also the latest innovative solutions for immersion cooling in data center cooling.

Contents will be published weekly, starting with November and going on for the following three months. So enjoy the reading, I hope it will prompt to further questions and more in depth insights to deploy and explore together!

Thermal energy and industrial processes

Tempco Energia termica

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Characteristics and applications of double wall heat exchangers

Prompted by a great and interesting video published by Kaori, our long partner for brazed plate exchangers, on its Youtube channel, let’s go talk about double wall heat exchangers.

Double wall heat exchangers are security type exchangers, having a peculiar construction with a double plate, hence their name ‘double wall’. This ensures that even in case of breaking or cracking of a plate, due to corrosion or other causes, the mixing between the primary and secondary fluid is avoided.

This is a kind of construction that can be applied both with brazed plate exchangers and gasketed plate exchangers, but also in shell and tube exchangers. This is employed wherever the mixing between the fluids is absolutely to be prevented. That’s the case of food industry for example, where products that have to be cooled before bottling, such as mineral water, beverages, milk or wine, don’t have to mix with cooling water, maybe not even potable.

Further applications are with hydraulic oil and diathermic oil, where the presence of water within the oil could lead to damages or also be extremely dangerous. The cooling of oil in power converters is another application field, where the mixing of oil and water can cause very expensive damages.

 

In gasketed heat exchangers the breakage of a gasket doesn’t lead to fluids’ mixing, because leakages go outside of the exchanger. Fluids can mix only in case of a crack in a plate. With double wall heat exchangers, even in case of cracking of a plate the leakage flows outside of the exchanger, making it immediately visible. In case of double wall shell and tube exchangers the leakage is not so immediately visible. In this case, there is a collecting chamber where leakages flow, and it can be equipped with special sensors alerting the maintenance team or the plant manager that a leakage happened, and thus that there is a cracked tube.

Clearly, double wall exchangers involve much higher costs, because at least the construction materials are doubled. In addition, the air space between the two walls decrease the thermal exchange coefficient, thus requiring an increase of the thermal transfer surface. This is even more impacting on shell and tube exchangers, yet usually offering lower thermal transfer rates, which further decrease with the addition of a tube in tube and an additional air space.

Anyway, double wall exchangers are a mandatory choice in all of those applications where it is necessary to avoid the mixing between the fluids.

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Cooling towers in high power converter testing

Pictured here is a cooling system we deployed for a testing chamber for power converters we’ve just supplied to a customer. The company is a manufacturer of IGBT, thyristors and diode type high power converters, that employ advanced electronics and digital regulation solutions.

Torre evaporativa test convertitori

The dissipation system dedicated to the testing of power converters we have supplied is a prefabricated skid package solution, that includes:

Evaporative tower
– Pumping group
Plate heat exchanger
Water softening and dosing system
– Electrical control cabinet with inverter on tower fans

In particular, in inverter allows to adjust the speed of fans based on external ambient air temperatures, ensuring the maximum cooling efficiency with the lowest power consumption possible.

Scambiatore test power converters

Tempco scambiatori test convertitori

The cooling in test operations for power equipments is a very well consolidated field of application for Tempco, thanks to the expertise and know-how built in several projects developed. Not too long ago, we’ve indeed already talked about a quite identical application for heat dissipation in the testing of inverters, made with a dry-cooler for lower power capacities.

 

Tempco test convertitori

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Advantages and characteristics of monofluid thermoregulation

Monofluid thermoregulation is a solution that offers important benefits, especially in application within pharma and chemical industry. These industries need to control temperatures in a bunch of production equipments, such as reactors, pressure filters, blenders and mixers. All of these machines require to maintain some rising or descending temperature ramps, involving a thermal range for the processed products that vary from low to high temperatures and viceversa.

An example is a reactor employed for the production of an active pharmaceutical ingredient. Starting from ambient temperature, the product has to be heated, and then maintained at a certain temperature. Then it has to be cooled, and then maybe again heated and so on.

Usually jacketed reactors are employed, with half-pipe coil or with thermal transfer jackets. Based on the temperature level required for the product inside the reactor, a hot or cold fluid is inserted within the jacket.

In the past, but still employed very much today, to achieve heating a hot fluid was inserted inside the jacket, vapor of diathermic oil for example. When the process needed a cooling phase, then vapor and condensate got completely discharged, and the jacket was then loaded with refrigerated water or glycol water. The ensemble of these discharging and loading operations clearly take some time, and thus can slow down the productivity. In addition, this kind of solution only offers a relatively precise control of temperature levels.

Hence, monofluid technology developed along the years. This technology employs in fact the same fluid as utilities – vapor, diathermic oil, hot water, refrigerated water, glycol water -, but they all flow within an array of heat exchangers. A unique fluid then flows inside the exchangers, which is able to withstand the temperature range required by the overall thermoregulation process.

This fluid flows then within the reactor’s jacket. There are clear advantages: downtimes are eliminated, related to discharge and loading operations of the different fluids. But most of all, the risk of mixing of the fluids is avoided. Which means there is no more risk of having antifreeze water flowing inside the boiler, or condensate ending up in the chiller, diluting the glycol water increasing the freezing risk.

Advantages are then significant, and clearly there are on the other hand some disadvantages. There is a slight loss in thermal exchange, indeed, due to the fact that the temperatures of utilities are a little bit higher and lower than the temperature of the fluid that flows within the jacket. But from an operative point of view, benefits are huge making it a largely implemented solution. Finally, there is no comparison in terms of temperature control that can be achieved: it is possible to operate using a switching valve, or bypass valves and regulating valves systems, that allow to obtain an extremely fine and accurate temperature regulation.

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