ABSTRACT

Swedish legislation stipulates the precision required for estimates of parameters used to determine the value of various forest fuels. The net energy value of fuel, as it is received, is often used to set the trade price. The estimate of energy content is based on the moisture content of samples taken from each truckload and the weight of the biomass; the ash content and net calorific value are measured a few times each year. Hence, it is necessary to know the variation in moisture content to ensure that a sufficient number of samples are taken, a number based on the allowed variation and precision of estimates, as defined in the legalization. In this study, the variation in moisture content was measured by taking samples from 18 truckloads of comminuted forest fuels during the winter. The results showed that the current sampling regime, i.e., manually taking four samples from each truckload, is sufficient for deliveries with 10 truckloads for logging residue chips and 4 for stem wood chips. The number of samples should be increased to 12–43, 8–21, and, 17–82 depending on assortment for what the measuring act defines as large deliveries (>=50 tonnes; >=3 truckloads), medium-sized deliveries (<50 – >25 tonnes; 2 truckloads) and single truck deliveries (<= 25 tonnes; 1 truckload), respectively. Current research into fast online sampling and analysis methods could resolve this issue for small deliveries.

摘要

瑞典法律规定了用于确定各种森林燃料价值的参数估计所需的精度。接收到的燃料的净能量值通常用于确定交易价格。能量含量的估算是基于从每个卡车上采集的样品的水分含量和生物质的重量；灰分和净热值每年测量几次。因此，有必要知道水分含量的变化，以确保获取足够数量的样品，该数量基于合法化中定义的允许变化和估计精度。在这项研究中，水分含量的变化是通过在冬季从18卡车装的粉碎过的森林燃料中取样来测量的。结果表明，当前的抽样制度，即 手动从每个卡车上取四个样品，足以交付10卡车来记录残留木片和4个用于干木片。样品的数量应增加到12–43、8–21和17–82，具体取决于测量行为定义为大批量（> = 50吨；> = 3卡车），中型（ <50 –> 25吨； 2卡车装载）和单卡车交付（<= 25吨； 1卡车装载）。当前对快速在线采样和分析方法的研究可以解决小批量交货的问题。17-82，具体取决于测量行为所定义的类别，包括大型交付（> = 50吨；> = 3卡车），中型交付（<50 –> 25吨； 2卡车）和单卡车交付（<= 25吨； 1卡车）。当前对快速在线采样和分析方法的研究可以解决小批量交货的问题。17-82，具体取决于测量行为所定义的类别，包括大型交付（> = 50吨；> = 3卡车），中型交付（<50 –> 25吨； 2卡车）和单卡车交付（<= 25吨； 1卡车）。当前对快速在线采样和分析方法的研究可以解决小批量交货的问题。