What's in a name?
The many different descriptions of Solex’s heat exchange technology
Author: Jamie Zachary
Today’s heat exchange technology for bulk materials comes in many different shapes, sizes and solutions.
From fluid and packed beds to screws and plates to rotary drums, the methods of transferring heat to or from a granular solid is incredibly diverse. The choice of which technology to use depends on any number of factors, whether that’s moisture removal, material characteristics, process specifications, carbon footprint or even its physical footprint within the plant.
Applications focused on indirect heat exchange by thermal conduction using steel plates are similarly diverse – or, to be more specific, what we call them. Here, we’ll dive into the many different names that Solex Thermal Science has come across to describe this technology.
Moving bed heat exchangers
Moving bed heat exchangers, or MBHEs, is a term commonly used today to describe technology that allows a “bed” of granular solids to flow by gravity down past solid surfaces that act as the interface for thermal energy transfer to or from a working fluid such as water or air.
The separation of the moving bed of solids from the heat transfer working fluid can be provided by vertically oriented plates (e.g., pillow plates, dimple plates, plate-coils, etc.), vertically oriented tubes or horizontally oriented round or oval-shaped tubes.
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MBHEs are found in a wide variety of applications where the primary function is to heat or cool free-flowing granular solids for the next step, whether that’s additional processing or, commonly, packaging, storage and/or transport.
Bulkflow heaters and coolers
The term “Bulkflow” pays homage to Solex’s roots. In 1989, a small team of engineers formed a division within what was then known as Cominco in Calgary, Alberta, Canada. The team focused on commercializing plate-based indirect heat exchangers for bulk solids following an initial installation at a fertilizer plant in nearby Carseland, Alberta (Interesting note #1: This unit is still running today!)
Over the next 10 years, the division expanded operations across North America and, later, Europe. In 1998, the division was purchased by the Calgary team of engineers and, in 1999, Bulkflow Technologies was formed with less than 12 employees. The newly formed company expanded the application of its signature “Bulkflow” coolers – and later heaters – to industries such as sugar, oilseeds and minerals.
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In 2008, the company was rebranded to what is known today as Solex Thermal Science, with more than 70 employees worldwide and 1,300 installations in 50-plus countries. (Interesting note #2: The Solex name is a combination of “solids” (Sol) and heat exchange (ex).)
Bulk solid cooler/heater
A bulk solid cooler or heater can refer to several different types of heat exchange technologies. That includes the vertical plate-based solutions that Solex provides – which, interestingly, traces its lineage to traditional plate heat exchangers (PHE) – as well as other alternatives such as horizontally orientated fluidized beds and rotary drums.
The key difference between the two is how the heat exchange takes place. In heat exchangers that use plates, the heat transfer takes place indirectly – that is, the solids do not come into contact with the working fluids when passing, uniformly, downward through the unit. With fluidized beds and rotary drums, for example, the air or gases pass directly through the solids as they are conveyed horizontally.
While commonly synonymous with plate heat exchangers, plate coil heat exchangers differ in that they are primarily employed for heating and cooling tanks containing chemicals and other fluids. This is particularly applicable when direct contact between the heating or cooling fluid and the process fluid is unfeasible.
Plate coils are often connected to Solex through Chemequip Industries Ltd., which operates www.plate-coil.com. The company, based in Shanghai, has worked in collaboration with Solex for almost two decades to develop the heat exchange market for bulk materials within the People’s Republic of China.
Also referred to as a bulk heating (or cooling) silo, this term is used to describe cases where a bulk material requires a long residence time.
Heat silos are commonly used to describe thermal treatment technologies that are based around a gravity-fed design, which is why it’s often used interchangeably with the plate-based units that Solex provides. However, it will often take the form of a tubular unit where both direct and indirect processes are possible.
The silo configuration is also commonly used in drying applications. As described by Greg Mehos and Eric Maynard in an article titled Efficient Drying of Bulk Solids in Silos, “gravity-driven flow in silos can provide the extended residence time needed to dry many bulk materials. To allow removal of a volatile component, usually water, a silo is equipped with heat exchangers or modified to permit injection of a gas. Such vessels have an assortment of names, including gravity dryers, purge or conditioning columns, and silo or hopper dryers.”
Last, but not least, is what’s simply known as The Solex. Given our company’s rich history over the past years in sectors such as fertilizer, oilseeds and sugar, our technology is commonly found in many plants around the world – more than 900 installations in 50-plus countries and counting.
And given the long operating lifecycle of “The Solex” (e.g., see the Carseland example above), these units are often the last ones standing!
Want to learn more about our heat exchange solutions? Let’s talk! Our team is available to discuss your process. Contact us today.
This entry was last updated on 2023-11-10
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