Jale Yanik

The slow and fast pyrolysis of cherry seed.

The slow and fast pyrolysis of cherry seeds (CWS) and cherry seeds shells (CSS) was studied in fixed-bed and fluidized bed reactors at different pyrolysis temperatures. The effects of reactor type and temperature on the yields and composition of products were investigated. In the case of fast pyrolysis, the maximum bio-oil yield was found to be about 44 wt% at pyrolysis temperature of 500 °C for both CWS and CSS, whereas the bio yields were of 21 and 15 wt% obtained at 500 °C from slow pyrolysis of CWS and CSS, respectively. Both temperature and reactor type affected the composition of bio-oils. The results showed that bio-oils obtained from slow pyrolysis of CWS and CSS can be used as a fuel for combustion systems in industry and the bio-oil produced from fast pyrolysis can be evaluated as a chemical feedstock.

Hydrothermal carbonization and torrefaction of grape pomace: A comparative evaluation

Grape pomace was treated by hydrothermal carbonization (sub-critical water, 175-275°C) and torrefaction (nitrogen atmosphere, 250 and 300°C), with mass yield of solid product (char) ranging between 47% and 78%, and energy densification ratio to 1.42-1.15 of the original feedstock. The chars were characterised with respect to their fuel properties, morphological and structural properties and combustion characteristics. The hydrothermal carbonization produced the char with greater energy density than torrefaction. The chars from torrefaction were found to be more aromatic in nature than that from hydrothermal carbonization. Hydrothermal carbonization process produced the char having high combustion reactivity. Most interesting was the finding that aqueous phase from hydrothermal carbonization had antioxidant activity. The results obtained in this study showed that HTC appears to be promising process for a winery waste having high moisture content.

The catalytic effect of Red Mud on the degradation of poly (vinyl chloride) containing polymer mixture into fuel oil

Thermal and catalytic degradation of poly (vinyl chloride) (PVC) containing polymer mixtures, PVC/PE, PVC/PP and PVC/PS, into fuel oil was investigated. In the catalytic degradations, Red Mud (a waste from alumina production) was tested as both cracking and dechlorination catalyst. For comparison, γ-Fe2O3 as a chlorine sorbent and SA-1 (silica alumina) as a solid acid catalyst were also used. The effect of degradation conditions, such as nitrogen gas flow, stepwise pyrolysis, catalyst contact mode, on the dechlorination was also investigated. The use of N2 gas flow suppressed partially the reaction between HCl gas from the degradation of PVC and polymer degradation products. By stepwise pyrolysis, over 90% chlorine in the feed plastic was recovered as HCl gas. SA1 catalyst accelerated the rate of polymer degradation and lowered the boiling point of liquid products, but the chlorine content of oil over SA1 was also the highest. Red Mud (RM) and iron oxides sorbents showed good effect on the fixation of evolved HCl. However, they had no effect on the cracking of polymers. The oils derived from PVC containing pure polymer mixtures by thermal degradation contained a lower amount of chlorine than the oils obtained using RM and other catalysts. From this result we conclude that the formation of some organic chlorine compounds may be promoted by the interaction of the HCl and the catalysts.

Pyrolysis of the tetra pak

This study deals with pyrolysis of tetra pak which is widely used as an aseptic beverage packaging material. Pyrolysis experiments were carried out under inert atmosphere in a batch reactor at different temperatures and by different pyrolysis modes (one- and two-step). The yields of char, liquid and gas were quantified. Pyrolysis liquids produced were collected as three separate phases; aqueous phase, tar and polyethylene wax. Characterization of wax and the determination of the total amount of phenols in aqueous phase were performed. Chemical compositions of gas and char products relevant to fuel applications were determined. Pure aluminum can be also recovered by pyrolysis.

Combustion behavior of different kinds of torrefied biomass and their blends with lignite.

In this study, the combustion behavior of different kinds of torrefied biomass (lignocellulosic and animal wastes) and their blends with lignite was investigated via non-isothermal thermogravimetric method under air atmosphere. For comparison, combustion characteristics of raw biomasses were also determined. Torrefaction process improved the reactivity of char combustion step of biomasses. Characteristic combustion parameters for blends showed non-additivity behavior. It was found that the mixture of torrefied biomasses and lignite at a ratio of 1:1 had a lower ignition and burnout temperature than the coal-only sample. Although no interactions were observed between the lignite and torrefied biomass at initial step of combustion, a certain degree of interaction between the components occurred at char combustion step. Kinetic parameters of combustion were calculated by using the Coats Redfern model. Overall, this study showed that poultry litters can be used as a substitute fuel in coal/biomass co-firing systems by blending with lignocellulosic biomass.

Characterization of products from hydrothermal carbonization of orange pomace including anaerobic digestibility of process liquor

In this study, the effect of the temperature and reaction time on hydrothermal carbonization (HTC) of orange pomace was investigated. In addition, a set of anaerobic batch tests were performed to determine the resulting biogas and methane potential of the spent liquor. Hydrochar yields followed a decreasing trend with the increasing temperature, whereas reaction time had no considerably effect on the yield. The evolution of the H/C and O/C atomic ratios from the raw material to the hydrochars suggested that dehydration reactions prevail during HTC. The hydrochars tended to become enriched in Ca, Mg and P minerals by increasing HTC temperature. The heavy metal contents in hydrochars were found below limits and no PAH compound was detected. Anaerobic digestion tests showed that the aqueous phase from HTC can be used as feedstocks for biogas production.

Hydrogen production from algal biomass via steam gasification

Algal biomasses were tested as feedstock for steam gasification in a dual-bed microreactor in a two-stage process. Gasification experiments were carried out in absence and presence of catalyst. The catalysts used were 10% Fe₂O₃-90% CeO₂ and red mud (activated and natural forms). Effects of catalysts on tar formation and gasification efficiencies were comparatively investigated. It was observed that the characteristic of algae gasification was dependent on its components and the catalysts used. The main role of the catalyst was reforming of the tar derived from algae pyrolysis, besides enhancing water gas shift reaction. The tar reduction levels were in the range of 80-100% for seaweeds and of 53-70% for microalgae. Fe₂O₃-CeO₂ was found to be the most effective catalyst. The maximum hydrogen yields obtained were 1036 cc/g algae for Fucus serratus, 937 cc/g algae for Laminaria digitata and 413 cc/g algae for Nannochloropsis oculata.

Activated carbon from leather shaving wastes and its application in removal of toxic materials.

In this study, utilization of a solid waste as raw material for activated carbon production was investigated. For this purpose, activated carbons were produced from chromium and vegetable tanned leather shaving wastes by physical and chemical activation methods. A detailed analysis of the surface properties of the activated carbons including acidity, total surface area, extent of microporosity and mesoporosity was presented. The activated carbon produced from vegetable tanned leather shaving waste produced has a higher surface area and micropore volume than the activated carbon produced from chromium tanned leather shaving waste. The potential application of activated carbons obtained from vegetable tanned shavings as adsorbent for removal of water pollutants have been checked for phenol, methylene blue, and Cr(VI). Adsorption capacities of activated carbons were found to be comparable to that of activated carbons derived from biomass.

Liquefaction of municipal waste plastics in VGO over acidic and non-acidic catalysts

Co-processing of municipal waste plastics (MWP) with vacuum gas oil (VGO) over HZSM-5, DHC-8 (commercial silica –alumina catalyst) and cobalt loaded active carbon catalyst has been comparatively studied. Co-processing experiments were carried out under hydrogen atmosphere at temperatures between 425 and 450 8C. The composition, sulphur and chlorine amount of liquid products were determined. The product distribution and the composition of liquids were changed depending upon the temperature and the catalyst type. As expected temperature led to increase in cracking activity of catalysts. DHC-8 and HZSM-5 showed substantially different activities in coprocessing due to the difference in their acidity. HZSM-5 gave highest gas yield at all temperatures and highest liquid yield (38.3) at low temperature. Although Co-AC was a neutral catalyst, it showed the cracking activity as well as HZSM-5 and more than DHC-8. No chlorine compound was observed in liquid products. The sulphur amount in liquid products varied with the catalyst type. Although HZSM-5 showed good cracking activity at low temperatures, it gave the liquid product containing highest sulphur amount. By considering both the quantity and quality of liquid fuel obtained from co-processing, it may be concluded that Co-AC gave the best result in the co-processing of the MWP/VGO blend. To observe the effect of metal type loaded on active carbon on catalyst activity, a series of co-processing experiments was also carried out. q 2002 Published by Elsevier Science Ltd.

Characterization of the oil fractions of shale oil obtained by pyrolysis and supercritical water extraction

Abstract Goynuk oil shale was subjected to slow pyrolysis and flash pyrolysis. It was also subjected to super and subcritical fluid extraction with water. Considerable differences were observed in the yields and compositions of the oils obtained under the four different conditions.