The document discusses the complexities of material handling in industrial biotechnology, emphasizing the need for rigorous testing of biosolids feedstocks to ensure effective technology selection. It provides guidelines on defining feedstock parameters, considering the differences between lab-scale and commercial-scale operations, and highlights the importance of plant layout design for maintenance accessibility and operational efficiency. Key considerations include moisture control, equipment redundancy, and future expansion possibilities.

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© Copyright 2017 Merrick & Company
By Chris Johnson, Matt Miller and Pam Buzzetta
Conceptual Design of
Material Handling Processes
Material handling is a complex part of any industrial biotechnology process. Biosolids feedstocks present unique
challenges at commercial scales due to the variability of their characteristics. Ensuring rigorous testing of representative
samples of the feedstock will de-risk the material handling technology selected in the long run. However, at the
conceptual stages, the following guidelines can help identify the right pathway for technology selection:
FEEDSTOCK PARAMETERS AND HANDLING CONSIDERATIONS
Carefully define the parameters of the feedstock and methods of handling with the following steps:
ƒƒ Ensure calculations use consistent units of measurement throughout (e.g. bone dry tons per hour, pounds per cubic
foot, etc.).
ƒƒ Testing should be performed on a representative sample. For example, if the feedstock will arrive at the processing
site as 6 inch strips of switchgrass that is 40% water weight, don’t expect that testing on 1 inch strips of switchgrass
that have been dried to 20% water weight will be a good approximation of the process in the field.
ƒƒ Consider that the conditions of the commercial scale plant may be very different than the lab scale. Lab scale
operations can easily dry the samples, have sharp blades on equipment for cutting the samples, and take time
processing samples. Lab processing is also typically batched and uses more human interaction, in general, than at
larger scale operations. The reality of the commercial operation may be 24/7 processing with equipment reaching the
end of its service life. Careful consideration for capacity, redundancy, maintainability, and durability can bridge the
gap between the lab and commercial scale operation.
UNIT OPERATIONS CONSIDERATIONS
Also, consider the unit operations that will be required to manage moisture and vapor removal/control. Many biosolids
have large water content that will be removed from the final biofuel or biochemical, which means it’s exiting the process
at some point. These vapors will likely need to be condensed and waste water treated before being discharged from the
process. If the feedstock is a waste stream from another process, the vapors during the initial material handling may also
need to be controlled to meet permit requirements.

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PLANT LAYOUT CONSIDERATIONS
The next consideration for material handling equipment is a well-designed plant layout.
ƒƒ Consider the accessibility of the equipment for normal operation as well as maintenance activities. For example, heat
exchanger bundles and pump motors will need to be pulled out of equipment for repairs, cleaning, and any future
modifications.
ƒƒ Understand the availability of equipment to perform these maintenance activities. A 150-ton crane may be the only
equipment that can be rented to move certain process equipment, so ensure the plant layout can accommodate the
crane accessing the equipment.
ƒƒ The placement of process units may also be crucial to a successful layout. For example, cooling towers should be
located at the edge of units, downwind of other units to avoid drift or splashing onto operating equipment, which could
accelerate external corrosion over time.
ƒƒ Redundancy of equipment and plot space for future expansion may also impact the total required area for the plant
and needs to be considered at early stages of the technology.