Abstract This paper presents a model for design optimization of pulp mill steam utility systems subject to variations in energy prices and steam demands. A Scandinavian Kraft pulp mill is used as case study to investigate investment opportunities in lignin extraction and new turbines. The model enables solutions to be identified that are more flexible than the solutions that would have been identified with a corresponding model using, for example, annual average values for key input data. The results from the case study show that lignin extraction has a potential to contribute to flexibility in pulp mill electric power production under certain conditions provided that the mill invests in both lignin extraction and condensing turbine capacity. However, the potential electric power production flexibility will vary over time. In the studied mill, with a capacity increased to around 1.3 million tonnes/a of pulp, it is estimated to vary between 15 and 30 MW. Furthermore, investment in new condensing turbine capacity only seems to be attractive if electricity prices that are considerably higher than the spot prices of recent years are assumed. Such prices may occur if there is a clear value of tradable electricity certificates or if future electricity prices rise significantly.

中文翻译：

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评估多元化副产品组合的价值，以提高纸浆厂的生产灵活性

摘要 本文提出了一种在能源价格和蒸汽需求变化的情况下优化纸浆厂蒸汽公用事业系统设计的模型。斯堪的纳维亚牛皮纸浆厂被用作案例研究，以调查木质素提取和新涡轮机的投资机会。该模型能够识别出比使用相应模型识别出的解决方案更灵活的解决方案，例如，使用关键输入数据的年平均值。案例研究的结果表明，如果纸浆厂对木质素提取和冷凝涡轮机容量进行投资，则在某些条件下，木质素提取有可能有助于提高纸浆厂电力生产的灵活性。然而，潜在的电力生产灵活性将随时间变化。在所研究的磨坊中，随着纸浆产能增加到约 130 万吨/年，估计在 15 到 30 兆瓦之间变化。此外，只有假设电价远高于近年来的现货价格，对新的冷凝式涡轮机容量的投资似乎才具有吸引力。如果可交易的电力证书有明确的价值，或者如果未来的电价大幅上涨，则可能会出现此类价格。