Experimental Parameter Study on Synthesis Gas Production by Steam-Oxygen Fluidized Bed Gasification of Sewage Sludge

2021 ◽  
Vol 11 (2) ◽  
pp. 579
Author(s):  
Max Schmid ◽  
Selina Hafner ◽  
Günter Scheffknecht

The conversion of biogenic residues to fuels and chemicals via gasification and synthesis processes is a promising pathway to replace fossil carbon. In this study, the focus is set on sewage sludge gasification for syngas production. Experiments were carried out in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agent. In-situ produced sewage sludge ash was used as bed material. The sensitivity of the key operation parameters gasifier temperature, oxygen ratio, steam to carbon ratio, and the space velocity on the syngas composition (H2, CO, CO2, CH4, CxHy, H2S, COS, NH3, and tars) was determined. The results show that the produced syngas has high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3 m−3, respectively, and is thus suitable for synthesis of fuels and chemicals. By adjusting the steam to carbon ratio, the syngas’ H2 to CO ratio can be purposely tailored by the water gas shift reaction for various synthesis products, e.g., synthetic natural gas (H2/CO = 3) or Fischer–Tropsch products (H2/CO = 2). Also, the composition and yields of fly ash and bed ash are presented. Through the gasification process, the cadmium and mercury contents of the bed ash were drastically reduced. The ash is suitable as secondary raw material for phosphorous or phosphate fertilizer production. Overall, a broad database was generated that can be used for process simulation and process design.

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 399
Author(s):  
Selina Hafner ◽  
Max Schmid ◽  
Günter Scheffknecht

Finding a way for mitigating climate change is one of the main challenges of our generation. Sorption-enhanced gasification (SEG) is a process by which syngas as an important intermediate for the synthesis of e.g., dimethyl ether (DME), bio-synthetic natural gas (SNG) and Fischer–Tropsch (FT) products or hydrogen can be produced by using biomass as feedstock. It can, therefore, contribute to a replacement for fossil fuels to reduce greenhouse gas (GHG) emissions. SEG is an indirect gasification process that is operated in a dual-fluidized bed (DFB) reactor. By the use of a CO2-active sorbent as bed material, CO2 that is produced during gasification is directly captured. The resulting enhancement of the water–gas shift reaction enables the production of a syngas with high hydrogen content and adjustable H2/CO/CO2-ratio. Tests were conducted in a 200 kW DFB pilot-scale facility under industrially relevant conditions to analyze the influence of gasification temperature, steam to carbon (S/C) ratio and weight hourly space velocity (WHSV) on the syngas production, using wood pellets as feedstock and limestone as bed material. Results revealed a strong dependency of the syngas composition on the gasification temperature in terms of permanent gases, light hydrocarbons and tars. Also, S/C ratio and WHSV are parameters that can contribute to adjusting the syngas properties in such a way that it is optimized for a specific downstream synthesis process.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Petutschnigg ◽  
Michael Stöckler ◽  
Florian Steinwendner ◽  
Julian Schnepps ◽  
Herwig Gütler ◽  
...  

Recently, the production of skis with wooden cores has increased due to changes in customer awareness concerning ecological issues and rising raw material costs for mineral oil resources. The preparation of ski surfaces is one of the main expense factors in the production of skis. Thus, one perspective of the AMER SPORTS CORPORATION is to treat wood surfaces with laser beams to develop new aesthetic possibilities in ski design. This study deals with different laser treatments for samples from various wood species: beech, ash, lime, and spruce. The parameters investigated are laser beam intensity and number of laser points on the surface. To evaluate the aesthetic changes, the CIELab color measurements were applied. Changes in the main wood components were observed by the Fourier transform infrared spectroscopy (FTIR) using an ATR (attenuated total reflectance) unit. The results show that the laser treatments on wood surfaces have an influence on wood color and the chemical composition. Especially the intensity of laser beams affects the color changes in different patterns for the parameters observed. These findings will be useful to develop innovative design possibilities of wood surfaces for ski cores as well as for further product design applications (e.g., mass customization).


2011 ◽  
Vol 6 (4) ◽  
Author(s):  
C. Peregrina ◽  
J. M. Audic ◽  
P. Dauthuille

Assimilate sludge to a fuel is not new. Sludge incineration and Combined Heat and Power (CHP) engines powered with sludge-derived anaerobic digestion gas (ADG) are operations widely used. However, they have a room of improvement to reach simultaneously a positive net power generation and a significant level of waste reduction and stabilization. Gasification has been used in other realms for the conversion of any negative-value carbon-based materials, that would otherwise be disposed as waste, to a gaseous product with a usable heating value for power generation . In fact, the produced gas, the so-called synthetic gas (or syngas), could be suitable for combined heat and power motors. Within this framework gasification could be seen as an optimum alternative for the sludge management that would allow the highest waste reduction yield (similar to incineration) with a high power generation. Although gasification remains a promising route for sewage sludge valorisation, campaigns of measurements show that is not a simple operation and there are still several technical issues to resolve before that gasification was considered to be fully applied in the sludge management. Fluidised bed was chosen by certain technology developers because it is an easy and well known process for solid combustion, and very suitable for non-conventional fuels. However, our tests showed a poor reliable process for gasification of sludge giving a low quality gas production with a significant amount of tars to be treated. The cleaning system that was proposed shows a very limited removal performance and difficulties to be operated. Within the sizes of more common WWTP, an alternative solution to the fluidised bed reactor would be the downdraft bed gasifier that was also audited. Most relevant data of this audit suggest that the technology is more adapted to the idea of sludge gasification presented in the beginning of this paper where a maximum waste reduction is achieved with a great electricity generation thanks to the use of a “good” quality syngas in a CHP engine. Audit show also that there is still some work to do in order to push sludge gasification to a more industrial stage. Regardless what solution would be preferred, the resulting gasification system would involve a more complex scenario compared to Anaerobic Digestion and Incineration, characterised by a thermal dryer and gasifier with a complete gas cleaning system. At the end, economics, reliability and mass and energy yields should be carefully analysed in order to set the place that gasification would play in the forthcoming processing of sewage sludge.


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 105
Author(s):  
Tae Young Kim ◽  
Seong Bin Jo ◽  
Jin Hyeok Woo ◽  
Jong Heon Lee ◽  
Ragupathy Dhanusuraman ◽  
...  

Co–Fe–Al catalysts prepared using coprecipitation at laboratory scale were investigated and extended to pilot scale for high-calorific synthetic natural gas. The Co–Fe–Al catalysts with different metal loadings were analyzed using BET, XRD, H2-TPR, and FT-IR. An increase in the metal loading of the Co–Fe–Al catalysts showed low spinel phase ratio, leading to an improvement in reducibility. Among the catalysts, 40CFAl catalyst prepared at laboratory scale afforded the highest C2–C4 hydrocarbon time yield, and this catalyst was successfully reproduced at the pilot scale. The pelletized catalyst prepared at pilot scale showed high CO conversion (87.6%), high light hydrocarbon selectivity (CH4 59.3% and C2–C4 18.8%), and low byproduct amounts (C5+: 4.1% and CO2: 17.8%) under optimum conditions (space velocity: 4000 mL/g/h, 350 °C, and 20 bar).


2021 ◽  
Vol 35 (6) ◽  
pp. 4997-5005
Author(s):  
Xiaoxia Yang ◽  
Shengshen Gu ◽  
Amanj Kheradmand ◽  
Yijiao Jiang

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3363
Author(s):  
Jolanta Latosińska ◽  
Maria Żygadło ◽  
Przemysław Czapik

Wastewater treatment processes produce sewage sludge (SS), which, in line with environmental sustainability principles, can be a valuable source of matter in the production of lightweight expanded clay aggregate (LECA). The literature on the influence of SS content and sintering temperature on the properties of LECA is scarce. This paper aims to statistically evaluate the effects of SS content and sintering temperature on LECA physical properties. Total porosity, pore volume, and apparent density were determined with the use of a density analyzer. A helium pycnometer was utilized to determine the specific density. Closed porosity was calculated. The test results demonstrated a statistically significant influence of the SS content on the specific density and water absorption of LECA. The sintering temperature had a significant effect on the specific density, apparent density, total porosity, closed porosity, total volume of pores, and water absorption. It was proved that a broad range of the SS content is admissible in the raw material mass for the production of LECA.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3106
Author(s):  
Tomasz Kalak ◽  
Kinga Marciszewicz ◽  
Joanna Piepiórka-Stepuk

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.


2019 ◽  
Vol 946 ◽  
pp. 169-173
Author(s):  
A.A. Biryukova ◽  
T.D. Dzhienalyev ◽  
A.V. Boronina

The purpose of the work is the obtaining of magnesium silicate ceramic proppants, based on ultrabasic overburden rocks of Kempirsai deposits of chromite ores (Kazakhstan). The chemical and mineralogical composition of ultrabasic overburden rock was studied by chemical, microscopic and X-ray diffraction analyzes. It is established that the main mineral of ultrabasic overburden rocks is serpentine, present in the form of fibrous chrysotile and lamellar antigorite. In the impurities are iron oxides and hydroxides, chrome spinel, carbonates, quartz. Assessment of the use of overburden rocks as a raw material for the production of ceramic proppants was carried out. The sintering interval of overburden rocks was determined at 1280-1300 °C. The sintering firing optimum temperature of ceramics, based on this type of raw material is 1300 °C. It is established that to harden the structure of magnesium silicate ceramic it is necessary to activate the raw material thermally at a temperature of 1000 °C. The influence of binder type on the properties of magnesium silicate proppants, based on the Kempirsai serpentinites was studied. Magnesium silicate proppants, based on ultrabasic overburden rocks, were obtained with the following properties: apparent density – 1.6 g/cm3, strength resistance (52 MPa) – 14%, sphericity and roundness – 0.8; chemical resistance (hydrochloric acid) – 98%, static strength of the fraction 16/20 - 72–118 N/granule. The field of application is oil and gas production, metallurgy and ceramic industries.


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