Project - Soft traceable online moisture measurement in wood chips

Project start: October 2017. Expected project completion: January 2020.

Danish CHP plants and district heating plants have replaced fossil fuels with renewable energy sources such as wood chips and wood pellets.

This change has meant that Denmark receives many small and medium-sized deliveries of biomass. The many deliveries causes a greater variation in fuel quality. Consequently, it is difficult with a smaller sampling to assess the water content in wood chips purchased and fired. An accurate analysis requires that a large amount of samples are taken, which is costly.

Purpose of the project:

The purpose of the project is to develop a method for qualifying measurements of water content in wood chips for biomass-fired plants. The work includes improved equipment for online measurement and sampling. Today, it is not possible to make a representative calibration on wood chips with commercially available online analyzers due to the great inhomogeneity of the fuel. This means that the measurements are unreliable and cannot be used in the management of a boiler. In addition, the measurements can neither be used for quality control of the wood chips nor used as a basis for estimation of price to be paid for a given amount of wood chips.

The project wishes to improve the opportunities for taking samples in an economically sound manner and has the following objectives:

• Identification of a reference analysis method
• Exploring the importance of the fuel composition (wood, bark, branches, needles, impurities).
• Optimization of sampling process
• Development of a representative calibration method
• Establishment of measurement system
• On-site evaluation of the measurement system efficiency and accuracy

Expected results

The result of the project is a measurement system consisting of interconnection of various commercially available equipment as well as an automatic sampling system that utilizes the strengths of different equipment. The sampling equipment should ensure input for the management of boilers while ensuring that settlement in the future can be based on the actual energy content of the fuel by taking into account the actual water content.