| 1. |
- Anukam, Anthony, et al.
(författare)
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A Review of the Chemistry of Anaerobic Digestion : Methods of Accelerating and Optimizing Process Efficiency
- 2019
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Ingår i: Processes. - Basel : MDPI. - 2227-9717. ; 7:8, s. 1-19
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Forskningsöversikt (refereegranskat)abstract
- The anaerobic digestion technology has been in existence for centuries and its underlying theory established for decades. It is considered a useful technology for the generation of renewable energy, and provides means to alleviate problems associated with low access to energy. However, a great deal of current research is targeted towards the optimization of this technology under diverse digestion process conditions. This review presents an in-depth analysis of the chemistry of anaerobic digestion and discusses how process chemistry can be used to optimize system performance through identification of methods that can accelerate syntrophic interactions of different microorganisms for improved methanogenic reactions. Recent advances in addition to old research are discussed in order to offer a general but comprehensive synopsis of accumulated knowledge in the theory of anaerobic digestion, as well as an overview of previous research and future directions and opportunities of the AD technology. Achieving a sustainable energy system requires comprehensive reforms in not just economic, social and policy aspects, but also in all technical aspects, which represents one of the most crucial future investments for anaerobic digestion systems.
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| 2. |
- Berghel, Jonas, 1966-, et al.
(författare)
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From sawdust to pellets. Still a challenge...
- 2012
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Ingår i: Public Service Review European Union. - : European union. ; :33, s. 398-399
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
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| 4. |
- Berghel, Jonas, 1966-, et al.
(författare)
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Lösningarna finns! Är pelletsproducenterna medvetna om problemen?
- 2011
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Ingår i: Bioenergi. - Gävle : Region Gävleborg. - 9789163391262 ; , s. 25-29
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Sverige är inte längre världsledande som pelletsproducent. USA producerar allra mest pellets i världen. Kanada och Ryssland producerar också allt mer pellets. Ingen av dessa länder har någon omfattande inhemsk konsumtion. I stort sett all pellets exporteras och det sker huvudsakligen till Europa. Sannolikt kommer det att leda till att priset på pellets i Europa sjunker, med följd att lönsamheten för svenska pelletsproducenter minskar.
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| 5. |
- Berghel, Jonas, 1966-, et al.
(författare)
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The effects of kraft lignin additives on wood fuel pellet quality, energy use and shelf life
- 2013
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 112:0, s. 64-69
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Tidskriftsartikel (refereegranskat)abstract
- In 2011, the total consumption of pellets in Sweden amounted to 1.9 million tons, which represents an energy value of 9 TWh. The pellets are used in large-scale as well as in small-scale applications, and increased demands on pellet quality are likely to force pellet producers to improve on the pellet properties. One way of increasing pellet quality is by using additives. The purpose of this article, therefore, is to examine kraft lignin as an additive. Pelletswere produced in a small industrial pellet press located at KarlstadUniversity, Karlstad, Sweden, and 1–4% of kraft lignin was added to the pellets. The results indicate that the addition of an increased amount of kraft lignin to the pellets increases their mechanical durability and their lengths. The results also indicate that dry kraft lignin yields pellets with higher durability as compared to wet kraft lignin. The energy demand was unaffected by the increased use of kraft lignin. The general results presented in this paper are useful for producers of lignin, pellet producers and end-users of pellets, who are interested in developing their products and/or improving the production processes.
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| 7. |
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| 8. |
- Eskandari, Samieh, et al.
(författare)
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Hydrochar-Amended Substrates for Production of Containerized Pine Tree Seedlings under Different Fertilization Regimes
- 2019
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Ingår i: Agronomy. - : MDPI. - 2073-4395. ; 9:7, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing body of research that recognizes the potentials of biochar application in agricultural production systems. However, little is known about the effects of biochar, especially hydrochar, on production of containerized seedlings under nursery conditions. This study aimed to test the effects of hydrochar application on growth, quality, nutrient and heavy metal contents, and mycorrhizal association of containerized pine seedlings. The hydrochar used in this study was produced through hydrothermal carbonization of paper mill biosludge at 200 °C. Two forms of hydrochar (powder and pellet) were mixed with peat at ratios of 10% and 20% (v/v) under three levels of applied commercial fertilizer (nil, half and full rates). Application of hydrochar had positive or neutral effects on shoot biomass and stem diameter compared with control seedlings (without hydrochar) under tested fertilizer levels. Analysis of the natural logarithmic response ratios (LnRR) of quality index and nutrient and heavy metal uptake revealed that application of 20% (v/v) hydrochar powder or pellet with 50% fertilizer resulted in same quality pine seedlings with similar heavy metal (Cu, Ni, Pb, Zn and Cr) and nutrient (P, K, Ca and Mg) contents as untreated seedlings supplied with 100% fertilizer. Colonization percentage by ectomycorrhizae significantly increased when either forms of hydrochar were applied at a rate of 20% under unfertilized condition. The results of this study implied that application of proper rates of hydrochar from biosludge with adjusted levels of liquid fertilizer may reduce fertilizer requirements in pine nurseries.
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| 9. |
- Frodeson, Stefan, Universitetsadjunkt, 1968-, et al.
(författare)
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The Potential for a Pellet Plant to Become a Biorefinery
- 2019
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Ingår i: Processes. - Basel : MDPI. - 2227-9717. ; 7:4, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- The use of bioenergy has increased globally in recent years, as has the utilization of biomaterials for various new product solutions through various biorefinery concepts. In this study, we introduce the concept of using a mechanical dewatering press in combination with thermal drying in a pellet plant. The purpose of the study is to increase the understanding of the effects a mechanical dewatering press has in a pellet production chain and investigate whether a pellet plant could thus become a biorefinery. The evaluations in this study are based on industrial data and initial tests at the university. The results show that the concept of using the mechanical dewatering press together with a packed moving bed dryer reduces energy use by 50%, compared to using only a packed moving bed dryer. The press water could be used as a raw material for biogas, bioplastics, and biohydrogen. Hence, this study points out the possibilities of a pellet plant increasing the efficiency of the drying step, while moving towards becoming a biorefinery.
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| 10. |
- From-Aldaron, M., et al.
(författare)
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Low Dosage Chemical Treatment for Improved Oxygenation of Pulp Mill Effluents
- 2018
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Ingår i: Journal of environmental engineering. - : American Society of Civil Engineers (ASCE). - 0733-9372 .- 1943-7870. ; 144:3
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Tidskriftsartikel (refereegranskat)abstract
- Most pulp and paper mills use aerobic biological treatment for their effluents. Aeration is the single most energy intensive process of a treatment plant. Surfactants, commonly occurring in pulping wastewaters, have been shown to decrease the oxygen transfer rate. The aim of this study was to decrease the surface activity of surfactants and thereby increase the oxygen transfer rate in pulp mill effluents by the use of chemical pretreatment in very low doses. Trials using 5 g/m(3) ferric iron showed statistically significant improvement on both k(L)a(@20) and surface tension. No sludge was precipitated owing to the very low ferric iron dosage. The novel use of chemical pretreatment, in very low doses, aiming specifically at improving oxygen transfer rate, is a promising concept for reducing the need for aeration in wastewater treatment and thus lower the electricity requirement of the wastewater treatment plant. (c) 2017 American Society of Civil Engineers.
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