Improving the power-to-heat ratio in CHP plants by means of a biofuel multistage drying system

Spets, Jukka-Pekka; Ahtila, Pekka

doi:10.1016/s1359-4311(02)00045-5

Cited by 10 publications

(4 citation statements)

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“…Drying of raw biomass prior to combustion or gasification can increase power production efficiency between 3 and 5%, depending on the drying method and the initial moisture content of the biomass (McIlveen-Wright et al, 2001;Spets & Ahtila, 2002). That may justify heating raw wood fuels in order to obtain rapid active drying (Johansson et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Determining the effect of storage conditions on the natural drying of radiata pine logs for energy use

Visser

Berkett

Spinelli

2014

New Zealand J For Sci

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Section: Introductionmentioning

confidence: 99%

Determining the effect of storage conditions on the natural drying of radiata pine logs for energy use

Visser

Berkett

Spinelli

2014

New Zealand J For Sci

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“…No separate drying processes were involved in the studied CHP plant, which comprehensively handled energy production. However, modern energy plants have fuel pre-drying systems for improving the energy efficiency of burning biofuels (Spets and Ahtila 2002). One reason for the integration of pulp and paper mills can be explained with energy savings: the slurry from the pulp mill can be pumped directly to a paper mill, thus avoiding the costly drying.…”

Section: Cost and Profit Evaluationmentioning

confidence: 99%

Activity-based costing method in forest industry – modelling the production and costs of sawing, the pulp and paper industry, and energy production

Korpunen¹

2015

Diss. For.

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3 Korpunen, H. 2015. Activity-based costing method in forest industry -modelling the production and costs of sawing, the pulp and paper industry, and energy production. Dissertationes Forestales 203. 47 p. http://dx.doi.org/10.14214/df.203 ABSTRACTAnnual commercial roundwood removal in Finland has reached approximately 50 million m 3 , delivering almost 1.6 billion Euros of stumpage earnings to forest owners. The aim of this dissertation is to study and model the production costs of saw-, pulp and paper mills and the combined heat and power (CHP) plant, which are the branches of forest industry that create most of the industry's wood-paying capability. The modelling was performed by implementing the activity-based costing (ABC) method for virtual greenfield mills located in Finland.Firstly, according to the principles of ABC, mill productions were divided into processes. The sawmills consisted of eight processes, while the pulp and paper mills of ten each and the CHP plant consisted of four processes. Secondly, all required production resources of each process were defined and quantified. Thirdly, the costs of each process caused by using the wood processing or energy use resources were allocated to the products or raw materials with cost drivers.Results of the example calculations indicated that the cost structures of the studied mills shared some similarities: wood, pulp or paper drying was a relatively expensive process. The share of drying was 40%, 39% and 18% of the annual costs in the sawmill, pulp mill and paper mill, respectively. The fluidized bed boiler represented 47% of the total costs of the CHP plant. Taking into consideration the practical limitations of the test calculations, the profitability of the pulp and paper mills and CHP plant were on a healthy level. The sawmilling case was left out of the profit calculations due to lack of market price information. According to the results, ABC was well-suited to the demands of forest industry. The models provide useful tools for cost-based decision-making for both forestry specialists and the forest industry. The results indicate that the sawing pattern is a very important cost factor in sawmilling, while energy production was crucial for the pulp and paper industry and the utilization rate was in a key position for CHP. From the forest industry viewpoint the models directly aid in performance analyses; results of the calculations revealed that the relatively high share of drying costs in the industry signals that the most cost-effective improvements could be found from energy savings, which has been the tendency in past years. These results can be combined with the forest end of the supply chain, whereby forest engineers have access to better control over tree-bucking optimization and different parallel value chains of forestry can be compared and evaluated with high accuracy.

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“…[2] or [3]. There are some cases in which the impact of drying to the CHP process is studied [4,5], but they are rare. We study here if using only CHP heat for drying is feasible.…”

Section: Introductionmentioning

confidence: 99%

Wood chip drying in connection with combined heat and power or solar energy in Finland

Rinne

Holmberg

Myllymaa

et al. 2014

EPJ Web of Conferences

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Abstract. 20% of the Finnish district heating (DH) power plant fuels are wood-based and the share is increasing. The wood fuel demand probably exceeds the potential supply in the future. The wood fuel drying with waste heat is one profitable opportunity to gain more wood fuel. If the drying energy can be produced with lower primary energy use than combusting the fuel directly, the drying potentially improves the system efficiency. In this study, the drying feasibility in the connection of a combined heat and power (CHP) system, possibly with solar collectors, is calculated. The wood fuel heating can be increased profitably by 6%, using the heat from CHP for drying only when the marginal cost of the heat is low enough, i.e. the electricity price is high enough and there is free capacity after the DH demand. Although the drying is profitable, a larger heat storage can also increase the annual result similarly. The best investment choice depends on the plant properties. Here the optimal system enables 20% DH production cost savings. Solar heat may be profitable, when the solar heat has a 2-3% share of the annual heat demand. However, the dryer or larger storage tank are more profitable investments.

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Improving the power-to-heat ratio in CHP plants by means of a biofuel multistage drying system

Cited by 10 publications

References 0 publications

Determining the effect of storage conditions on the natural drying of radiata pine logs for energy use

Determining the effect of storage conditions on the natural drying of radiata pine logs for energy use

Activity-based costing method in forest industry – modelling the production and costs of sawing, the pulp and paper industry, and energy production

Wood chip drying in connection with combined heat and power or solar energy in Finland

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