Dense vs. Dilute Phase Pneumatic Conveyance: How to Choose the Right Option for your Application

It is the beginning of a planning session for a new plant expansion project. You know you want to pneumatically convey your material, but you do not know the best operational and cost effective solution to use. Do you choose a dilute or dense phase pneumatic conveyance system? Within each type of convey system there are different categories of conveyance: positive pressure, vacuum, and combination. This article will discuss positive pneumatic conveyance systems.

Let’s start by discussing some of the differences between the two types of conveyance. The chart below highlights some typical, basic operational differences between the two types of pneumatic conveyance systems.

Before you narrow down your system based solely on the process parameters, it is critical to understand the different types of equipment the dense and dilute phase systems need. Often, available footprint can govern which type of pneumatic conveyance system is chosen. Of course, depending on the complexity of the process, there may be additional equipment included. This list covers only the minimum equipment required for each type of conveyance system.

Now you have used the chart to narrow down the type of system you think you need, but are you confident that you made the right assumption? As with any expansion project in discussion these days, the return on investment or ROI is a critical requirement. For early phase projects, the entire project can be estimated based on factoring the estimated equipment costs. Top obtain the equipment costs, you must first size the equipment.

For early phase projects, equipment sizing can be acceptably estimated utilizing dual phase calculations; solid and gas. We, at D&Z, have developed proprietary in-house tools which allow us to estimate equipment sizes for early phase projects, FEL 1 and FEL 2. For this reason, it has become more common for our team to provide assistance to our clients during these early project planning phases. Our tools allow us to provide comparative pricing estimates for our clients between dense and dilute phase pneumatic conveyance systems or even with hybrid conveyance systems. We even offer assistance using these comparative pricing estimates for the ROI evaluations.

Utilizing the information outlined in this article, the type of pneumatic conveyance system has been chosen as the basis for the project design. As the project moves from the early phase, FEL 1 and 2, to a more concrete design, it is critical to use the expertise of a pneumatic conveyance system manufacturer. These experts will define whether and where booster nozzles or balancing valves are needed. Air leakage rates can be determined by evaluating specific leak points, so operational costs can be better estimated. The ultimate project goal being to provide a quality and cost effective pneumatic conveyance system that will successfully serve the plant for years.

ABOUT THE AUTHOR

Audrey Hooper is a lead mechanical engineer and material handling subject matter expert for Day & Zimmermann’s Process & Industrial Group. She holds Professional Engineer’s licenses in multiple states, and she is the qualifying agent for D&Z’s Construction Manager and Commercial General Contractor licenses in multiple states. Mrs. Hooper has 20 years of experience developing Material Handling and Process Equipment designs from initial concepts through the detail design and construction phases to successful field operation. She has experience in Power, Refining, Chemicals, Plastics, Fibers, Spinning, Aerospace, Nuclear, Metals, Bio-Pharma, and Alternative Fuels industries.