Bulk Solid Heat Exchangers

Bulk Solid Heat Exchangers

Pillow plates bulk solid heat exchangers. Design and calculation 10 – 250 TPH.

Complete dimensioning and 3D tower drawings.

A BSHE (bulk solid heat exchanger, also called moving-bed heat exchanger) cools, heats, dries or conditions free-flowing granules, crystals, pellets or powder as they flow by gravity between vertical pillow plates. The product slides in mass flow through the gaps. Water, glycol, thermal oil, steam, refrigerant or — for high-temperature duties — air or gas runs inside the pillows.

Heat transfer is indirect conduction. The process air mass is not the cooling or heating medium. A small purge or sweep-air stream, if used, only keeps the dew point off the plate or carries evaporated moisture.

Typical products: sugar, urea, NPK, CAN, DAP, MAP, ammonium sulphate, potash, plastic pellets, salt, seeds, oilseeds, grains, sand, foundry sand and minerals.

Keppels Laser Welding designs the plates, calculates the heat transfer with own BSHE software and can supply complete ready-to-install pillow plates. The same IPG fiber laser machines that weld tank jackets and falling-film plates weld these banks.

Examples from recent work:

• BSHE for sugar cooling 100 TPH
• BSHE for NPK 30–200 TPH
• BSHE for special application (NDA, no public information)

Cooling, heating, drying and conditioning

The same plate-bank geometry covers four duties. Packaged-tower brands sell complete casings and feeders; Keppels supplies the pillow plates, the calculation and — if required — the 3D bank design so amanufacturer can complete the tower.

• Cooling — product leaves a dryer, granulator or reactor and must be brought to storage or bagging temperature. Water or glycol inside the plates. High inlet temperatures are a project design (alloy, expansion, plate thickness), not a copied jacket pattern.
• Heating — hot water, thermal oil or steam inside the plates. Waste warm water or low-pressure steam can drive the duty when the real temperatures are known.
• Drying / conditioning — plates supply the heat; a defined sweep-air stream carries the moisture. Temperature and moisture can be set independently, unlike a fluid bed where the same air does both jobs.
• Conditioning of oilseeds and grains — heat and moisture to a prescribed window before extraction or storage.

Why a pillow-plate BSHE instead of a fluid bed or rotary drum

• Indirect liquid or steam inside the plates replaces a large process-air mass. Energy use is typically far lower than a fluid bed or rotary drum on the same temperature duty. Do not treat a single percentage as a universal figure; the saving depends on the boundary.
• Near-zero process emissions and little dust carry-over, because the solid is not fluidized.
• Compact vertical footprint. Capacity is raised by adding plate width or stacking modules, not by a larger hall floor.
• Low product inventory on the medium side. Waste heat from elsewhere in the plant can be used as hot water or low-pressure steam.
• No moving parts in the plate bank. Individual plates can be designed for hose connections so one plate can be isolated, removed or replaced.

A BSHE is first a temperature machine. It is a poor first choice for sticky filter cake, solids that sinter on the wall, products that will not mass-flow in a vertical gap, or duties that need high-shear mixing or a large drying-air mass.

How the tower works

• Solids enter a hopper and move downward between vertical double-embossed pillow plates.
• A mass-flow discharge feeder at the bottom sets the velocity and draws across the full section. Funnel flow (fast centre, stagnant walls) gives uneven product temperature and can cake on the plates.
• Heat-transfer fluid runs inside the plates, usually counter-current to the solids. Co-current and multi-bank arrangements are possible.
• Residence time in fertilizer and sugar projects is often several minutes (commonly about 5–15 minutes). That is experience, not a standard.
• Clear gap between plates is project-specific. For free-flowing granules such as urea, sugar and plastic pellets a gap of about 20–40 mm is common. Closer plates: shorter conduction path, more area, higher bridging risk.
• Banks can be staggered so particles that sat near a wall in one bank sit in the centre of the next gap.

Standard BSHE plate specifications

What Keppels can supply

• Heat-transfer calculation and dimensioning (own BSHE differential model on the moving bed).
• 3D drawings of the plate bank / tower.
• Laser-welded pillow plates, flat or inflated, ready to install.
• Tower, pattern, thickness and gap matched to product, mass flow and target temperatures.
• In-house granulate conductivity measurement when material conductivity specification is unknown.
• Install and commissioning of the BSHE tower.

Keppels is an independent supplier of BSHE engineering, pillow-plate technology and laser welding machines. Keppels can guide the BSHE customer to the right manufacturer of the BSHE tower.

The BSHE plates are laser-welded on a Keppels K1500 or K2000 pillow plate laser welding machine.

Enquiry data

Drawings and prices on request. Send (if information available):

• Product and grade, Specific heat, Conductivity value, particle size, bulk density, moisture.
• Mass flow (TPH or kg/h).
• Inlet and target outlet temperature Solid.
• Allowed plate gap and available height / footprint.
• Medium type and temperatures (water, glycol, oil, steam, refrigerant).
• Required design reserve.
• Heat recovery possibilities.

Specials on request with drawing or custom specification.

FAQ Bulk solid heat exchangers

Production partner in BSHE