Bulk solids heat transfer and waste heat recovery

In many industrial processes, bulk granular solids undergo thermal treatment to meet or provide final product specifications. Yet, many of these processes also leave waste heat on the table.

In the July 2021 issue of Process Heating magazine, Solex Thermal Science Global Director of Industrials Gerald Martinisch discusses the concept of useful energy going to waste and why it has become less acceptable in our modern global community.

0721 Process Heating cover imageHe further explains how bulk solids heat exchangers, also referred to as moving-bed heat exchangers (MBHE), are increasingly being looked upon to recover thermal energy from granular solids and make it available for reuse in multiple ways, such as:

  • The heat from bulk solids is exchanged to other working fluids such as water, steam, thermal oil, air or even supercritical carbon dioxide (sCO2). This exchange allows the thermal energy to be used in other processes in the plant.
  • In cases where the recovered waste heat cannot be used in the production or manufacturing process, the energy recovered above temperatures of 752°F (400°C) is used to generate electricity in steam or gas turbines, organic Rankine cycles (ORC) and sCO2 cycles.
  • Low-grade heat left over from electricity generation can be used to heat other areas of the plant or operate absorption chillers that generate cold (chilled) water.
  • In some scenarios, the low grade heat can be supplied to a plant- or district-heating network.

Learn more about how the technology works, including the potential savings around primary energy costs. Read the full story in Process Heating magazine's all-new e-magazine format. Or download a pdf version.

This entry was last updated on 2022-5-2

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