ScanChip

The challenge

Analyzing wood chips online or in the laboratory to get fast and accurate information on chip quality for optimization of the pulping process.

The solution

The ANDRITZ optical ScanChip analyzer for online or laboratory chip quality analysis.

ScanChip analyzer

The ANDRITZ ScanChip analyzer uses image analysis technology to monitor chip quality in a fast and accurate way. The ScanChip system is designed for either online version integrated with the pulp mill’s control system or offline as a laboratory instrument.  It can also be equipped with an automatic chip sampling device to take regular, representative samples from the chip flow, whereby the ScanChip provides a safe online chip quality measurement system. The analyzer defines chip quality in accordance with testing or mill standards like the SCAN method. Depending on where one wants to utilize the analysis results, the analyzer can be installed in various positions, for example after the chipper or before the pulping process. The chips are monitored in a fast and accurate way so that the pulping process can be adjusted to match actual chip quality.

The ScanChip system is beneficial for:

• Obtaining accurate and frequent chip quality data so that the pulping process can be adjusted to match actual chip quality (e.g. chip size distribution information used to optimize cooking control)
• Optimizing the interval between chipper knife changes
• Documenting the quality of purchased chips to ensure proper payments
• Replacing labor-intensive chip sampling and laboratory tests
• Defining chip quality in accordance with testing or mill standards like the SCAN method

Optional measurement modules analyzing moisture or  brightness

Measurement modules can be added for monitoring chip moisture and chip brightness. The modules are fully integrated into the ScanChip system. By measuring the chip moisture in a ScanChip installed before the pulping process, the amount of water in the chips will be a known parameter. This will give important information to the digester control system. Measuring the chip brightness is mostly important for the thermomechanical TMP process. Darker chips needs more bleaching agents. Knowledge of this will be an important tool for optimization of the TMP bleaching process.

Automatic chip sampler

The automatic chip sampler is designed to collect representative samples from the chip flow and is mounted directly to the chip chute and it can be placed in optional positions in the mill. In ScanChip online version the analyzer is equipped  with an automatic chip sampler and one or more return conveyors for returning the samples to the main chip flow, whereby the ScanChip provides an online chip quality measurement system. By using an automatic chip sampler a safe handling when collecting chip samples in the process is ensured.

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