Char

The present work aims to evaluate the potential of producing bio-oils and chars from biomass residues through fast pyrolysis. Pinewood and agro-biomasses – olive bagasse, wheat straw and rice husk – were pyrolysed in a bench scale screw reactor at 580 ºC using a carrier gas flow rate of 526 mL/min in order to maximize the resultant bio-oil fraction. The yields of bio-oil, bio-char and gas obtained were
quantified. Bio-liquid yields varied between 51 wt.% for pinewood and 31 wt.% for olive bagasse and the bio-char yields between 38 wt.% for wheat straw and 24 wt.% for pinewood. Subsequently, the bio-oils and chars obtained were analyzed in terms of moisture content, elemental analysis, ash content and heating value. The main conclusions are as follows:
1) pinewood showed the highest potential to pyrolyse; the resultant bio-oil and char have potential to be used as fuels without further treatments.
2) The substantial ash content in the feedstock of the agro-biomasses decreased drastically their bio-oil quality and yield. Furthermore, the low conversion yields related to such biomasses observed in the present work may not justify their valorisation through pyrolysis.
3) The non-homogeneity of the bio-oils from agro-biomasses is a higher challenge to their use as fuel, however, is an opportunity for recovering added-valued by-products. 4) The chars obtained from agrobiomasses with higher ash content and lower energy densities may have potential to be used in the preparation of active carbon when its pore structure and surface are appropriate.

Wood wastes are one of the leading contributors of greenhouse gases cum climate change. While the burning of wood wastes results in CO2 emission, decomposition generates methane. In place of these emissions, wood wastes can be converted into biochars which have a lot of novel applications. However, low biochar yield was the common limitation of wood wastes, essentially, due to a mixture of different classifications of trees that pyrolyse at different conditions. In this study, biochar yield from sorted wood wastes was optimised by varying pyrolysis temperature and time. Power consumption, cost, and carbon footprint of the optimised biochar and ash were compared for both hydropower grid and diesel generator scenarios. Optimal pyrolysis yields were 33.6 % (400 °C), 29.4 % (350 °C) and 18.5 % (400 °C) respectively for hardwood sawdust char (HSC), softwood sawdust char (SSC), and mixed sawdust char (MSC) at 2 hours duration for all materials. The CO2 emissions from ash were 2.49 kg and ...

Mismanagement of Medical wastes can lead to human health and environmental risks. Currently, new pyrolysis technologies are being used to treat medical waste that can reduce the amount of landfilled waste, make it safe, and eventually convert it to a hydrocarbon fuel. Polycyclic aromatic hydrocarbons (PAHs) are pyrolysis by-products and major environmental pollutants. In this study, hazardous medical wastes were pyrolyzed using a semi-industrial pilot scale fast pyrolysis reactor with the purpose of improving the quality of the char for its recovery or use as fuel. The generation of total 4-6 rings PAHs was studied in char product from hazardous medical waste fast pyrolysis under different pyrolysis conditions variables including a vast temperature range (300-700°C), different residence times (100-190 s) and various waste particle sizes (1-3 cm). GC analyzer coupled with a FID detector was used to detect and measure the PAH compounds in char residues. The results demonstrated that the PAHs are present in significant concentrations in char product (54-1184 mg kg-1). Generation of total 4-6 rings PAHs varied by temperature, residence time and waste size. Significant interaction was observed between residence time and temperature that influenced the PAHs generation. By optimizing the pyrolysis operating conditions it is possible to minimize the amount of PAHs generation in the char.

In this study, tire tread (TT) and side wall (SW) of waste tire were separately used as feedstocks for pyrolysis treatment, and the resulting chars were thoroughly characterized to exploit the potential applications. Analytic results show that the SW contained higher fixed carbon (27.55%) and carbon content (82.30%) than those of TT (15.21% and 56.56% respectively). TGA results indicated that 400–600 °C is the main decomposition tem- perature range for both feeds. The char yields showed a declining trend and stabilized at 500 °C, and higher char yield of TT was achieved than that of SW. Meanwhile, the chars from TT showed a high surface area (121.47 m2/ g) than that ofSW (44.72 m2/g), which could be a good adsorbent or an activated carbon precursor. FT-IR results showed that leading surface functional group of TT-500 was C-O/C-O-C from alcohols, ketones or ether, whereas SW-500 from phenols, alcohols and carboxylic acids. When compared with commercial products, SW-500 showed better properties than those of a carbon black (N660, 10 μm) in terms of carbon quality and ash content. This study suggested that by pyrolyzing the distinct sections of the waste tire is a promising approach to produce chars for more specific applications.

Pirolysis is thermochemical decomposition process of biomass into useful product. One kind of method that can be used is a Rotary Kiln pirolyzer which is consist a heating cylinder that rotates with a certain rotation speed. This research is aimed to get the effect of temperature due to Char product quantity of switenia macrophylla Rotary Kiln pirolysis.The research has done by pirolysis experiment with 200 gram of switenia macrophylla in dust form. Temperature was varied 250 C, 350 C, 450 C, 500 C, and 600 C. The heating temperature was provided by eletric heater with control system. Temperatur was measured with K type thermocouple. The heating process has taken for 180 minutes using stopwatch. The measurement has done for biomass and Char volume using measuring cup. Mass was measured by using mass scale. Low heating value was measured by using bomb calorimeter. The result show that the temperature has effect due to Char product of switenia macrophylla Rotary Kiln pirolysis. The loss of Char mass is tend to increase due to temperature increases. Low heating value and Char porosity is tend to increase due to mass loss percentage increases. Shrinking factor and percentage of yield energy is tend to decrease due to mass loss percentage increasing.

Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. We tested the chemical convergence hypothesis i.e. materials with different initial chemistry converge towards a common profile, with similar biological effects, as the oxidative process advances, for burning and decomposition. We compared the molecular composition, assessed by 13 C NMR, of 7 plant litter types either fresh, decomposed for 30, 90, 180 days in a microcosms incubation experiment, or heated at 100, 200, 300, 400, 500 °C for thirty minutes. We used litter water extracts (5% dw) as treatments in bioassays on plant (Lepidium sativum) and fungal (Aspergillus niger) growth, and a washed quartz sand amended with litter (0.5% dw) to assess heterotrophic respiration by flux chamber (i.e. μg of CO2 released per g of added litter per day). We...

Soil stabilization for use in pavement sublayers has been established in Geotechnical En-gineering as an option for pavement construction. In this context, certain alternative materials stand out, such as coal and biochar, which are able to fulfill this function when added to the soil, being the object of study in the present research. These products originated from char-coal furnaces and biomass carbonization under low oxygen atmosphere. In the present study we evaluated the natural soil and compositions according to the four-point bending test, for simulating vehicle tire-loads on the pavement. For this purpose, we molded prismatic speci-mens with natural soil (NS) typical of the Amazon region, with natural soil-10% charcoal (SCH) and soil-10% biochar (SBC). It was verified that the soil-biochar mixture (SBC) pre-sented better results, culminating in higher values of complex modulus when compared to the natural soil (NS) and soil-charcoal mixtures (SCH). Regarding the phase angle ...

Abstract The products obtained by carbonization of a mixture of hydrothermally dewatered acid washed Victorian brown coal and coking coal tar pitch, which had been briquetted at 150 or 230 °C and air cured were shown to approach blast furnace (BF) coke in many of their properties. The samples had higher strength than BF coke and showed surface areas and reactivities much closer to those of a typical BF coke than products from non-hydrothermally dewatered Victorian brown coal prepared under similar conditions. The reactivity showed a good correlation with the relative amount of graphitic structure determined by Raman spectroscopy.

Abstract. Gasification of biomass and different types of waste now is considered as one of most perspective ways for production of heat and electricity. It is necessary to clean the synthesis gas from tar and soot particles in order to use it in turbines and micro turbines, internal combustion engines for electricity production, chemical reactors for syn-thetic fuel or chemicals production. The main objective of this work is investigation of catalytic tar destruction in order to evaluate two selected catalysts, namely dolomite, available in Lithuanian as natural resource, and char derived from pyrolysis of used tires. The effi-ciency of these catalysts were investigated as an ability to decompose tar hydrocarbons at high temperatures and op-timal process conditions were determined, which are base starting point for developing new functional material and technological solutions. Results of catalytic steam reforming of two main tar compounds from biomass gasification – benzene and nap...