At the end of this module, you will be able to:
- Identify safety hazards and their related guidelines for white water systems
- Identify the three main objectives of a white water system
- Define "rich white water," "lean white water," "short circulation loop," and "long circulation loop"
- Describe the criteria used to size white water storage chests
- Identify major components of the short and long white water circulation loops
- Identify the purpose or function of each major white water system component
- Identify and describe the primary process flows of each major white water system
The following key questions are answered in this module:
What is the difference between rich and lean white water?
The white water removed from the sheet early on the former tends to contain more solids (fibers, fines, and fillers), and so it is often called "rich" white water. Water removed later on the former is often referred to as "lean white water" because it contains fewer solids.
Where is rich white water collected?
Rich white water is typically collected in a wire pit, or a wire tray and flume, and directed to a silo.
Where is lean white water collected?
Lean white water that is removed from the sheet by suction boxes in the forming section and press section is often piped to a separator on the back side of the machine.
What is clarified white water used for?
Clarified white water is used for shower water and dilution water.
What are the objectives of the white water system?
The white water system should provide adequate quantities and qualities of white water to all points in the process, maximize reuse of white water in order to reduce fiber and energy losses and minimize effluent loads, and minimize fresh water makeup, as fresh water must be heated up to process temperatures and may require pH adjustment.
Below is a transcript of the video sample provided for this module:
White water is the drainage water from stock or furnish on a paper or board machine that contains valuable fibers, fines, residual chemicals, and heat. White water is not always white as it takes on the color of the fibers and fines it contains. The purpose of a white water system is to collect and reuse as much white water as possible in order to recover valuable resources while minimizing fresh water usage and effluent flows.
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