| 1. |
- Teghammar, Anna, 1981, et al.
(författare)
-
Enhanced biogas production from rice straw, triticale straw and softwood spruce by NMMO pretreatment
- 2012
-
Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 36, s. 116-120
-
Tidskriftsartikel (refereegranskat)abstract
- Softwood spruce (chips and milled), rice straw and triticale (a hybrid of rye and wheat) straw, were pretreated with N-methylmorpholine-N-oxide (NMMO or NMO) prior to anaerobic digestion to produce biogas. The pretreatments were performed at 130 degrees C for 1-15 h, and the digestions continued for six weeks. The digestions of untreated chips (10 mm) and milled (
|
|
| 2. |
- Teghammar, Anna, 1981, et al.
(författare)
-
Improved Anaerobic Digestion by the Addition of Paper Tube Residuals: Pretreatment, Stabilizing, and Synergetic Effects
- 2013
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 27:1, s. 277-284
-
Tidskriftsartikel (refereegranskat)abstract
- This study deals with the addition of paper tube residuals to a nitrogen-rich mixture of organic waste obtained from industrial and municipal activities. This nitrogen-rich mixture, called buffer tank substrate (BTS) in the following text, is used in a large-scale biogas plant. The effects were investigated in semi-continuous co-digestion processes, and variations in operational conditions were studied. The addition of paper tubes had stabilizing effects, prevented the failure of the process, and made it possible to decrease the hydraulic retention time from 25 to 20 days. Furthermore, synergetic effects were found, with 15-34% higher methane yields, when paper tubes were co-digested with BTS. Moreover, steam explosion pretreatment of the paper tube waste with the addition of 0-2% NaOH was evaluated by batch digestion experiments. Increasing the NaOH concentrations used in the pretreatment resulted in increasing methane yields, with the highest of 403 N mL of CH4 g(-1) of volatile solids (VS) corresponding to an increase by 50% compared to that when untreated paper was digested (268 N mL of CH4 g(-1) of VS). The long-term effects of this best pretreatment were further investigated by continuous co-digestion experiments, leading to a higher methane yield when pretreated paper tubes were used in the co-digestion process compared to untreated.
|
|
| 3. |
- Teghammar, Anna, 1981, et al.
(författare)
-
Pretreatment of paper tube residuals for improved biogas production
- 2010
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 101:4, s. 1206-1212
-
Tidskriftsartikel (refereegranskat)abstract
- Paper tube residuals, which are lignocellulosic wastes, have been studied as substrate for biogas (methane) production. Steam explosion and nonexplosive hydrothermal pretreatment, in combination with sodium hydroxide and/or hydrogen peroxide, have been used to improve the biogas production. The treatment conditions of temperature, time and addition of NaOH and H2O2 were statistically evaluated for methane production. Explosive pretreatment was more successful than the nonexplosive method, and gave the best results at 220 degrees C, 10 min, with addition of both 2% NaOH and 2% H2O2. Digestion of the pretreated materials at these conditions yielded 493 N ml/g VS methane which was 107% more than the untreated materials. In addition, the initial digestion rate was improved by 132% compared to the untreated samples. The addition of NaOH was, besides the explosion effect, the most important factor to improve the biogas production.
|
|
| 4. |
- Teghammar, Anna, 1981, et al.
(författare)
-
Substrate Characteristic Analysis for Anaerobic Digestion: A Study on Rice and Triticale Straw
- 2012
-
Ingår i: BioResources. - : North Carolina State University: College of Natural Resources. - 1930-2126 .- 1930-2126. ; 7:3, s. 3921-3934
-
Tidskriftsartikel (refereegranskat)abstract
- Different substrate characteristic analyses have been studied on rice and triticale straw pretreated with NMMO (N-methylmorpholine-N-oxide) prior to biogas production. Simons' stain, water retention value (WRV), and enzymatic adsorption were used to measure the change in the accessible surface area of the lignocellulosic substrates. FTIR was used to measure the change in cellulosic crystallinity and Time-of-Flight-Secondary-Ion-Spectroscopy (ToF-SIMS) to measure the ratio of cellulose to lignin on the sample surface. All methods showed increased accessible surface area and a decrease in crystallinity after the pretreatments. These qualities were linked to improved biogas production. In the future, the tested methods could replace the time-consuming methane potential analysis to predict the methane production of lignocellulosic materials. Simons' stain, enzymatic adsorption, and crystallinity measurement by FTIR can be regarded as the recommended methods for the prediction of the improved biogas production as a result of the pretreatment.
|
|
