Effect Of Feedstock Composition Research Articles

Cracking of F-T refined wax for producing linear α-olefin

The steam cracking of Fischer-Tropsch refined wax from the coal-to-oil process for producing linear α-olefin (LAO) was carried out on a fixed bed reactor. The effects of feedstock composition, cracking temperature, contact time, water-to-wax ratio and cyclic process on the feed conversion and products distribution were investigated and optimized. The factors such as cracking temperature and contact time have significant influence on conversion and LAO yield, and cyclic process can further improve the LAO yield. However, excess high cracking temperature and longer contact time result in the second reactions, which are unfavorable for the LAO production. Under the suitable process conditions 53% of LAO yield are obtained.

Few-walled carbon nanotubes derived from shoe waste plastics: Effect of feedstock composition on synthesis, properties and application as CO2 reduction electrodes

This work investigates the chemical recycling of shoe waste plastics, i.e. polyurethane (PU) and ethylene-vinyl acetate (EVA) using a pyrolysis-chemical vapor deposition process over Fe/MgO catalyst. Results suggested PU facilitated highly selective production of few-walled CNTs with small diameters and narrow size distribution while EVA tended to yield multi-walled CNTs. The synergistic interactions between pyrolysis gases components from PU and EVA allowed facile tailoring of CNT size distribution by using either sorted PU and EVA or mixture (EVA/PU) in appropriate ratios. CNTs derived from pure PU or EVA/PU were more suitable in designing effective electrocatalysts for CO2 reduction with Faradaic efficiency of 85–95% and CO current density of >9 mA cm−2. This was because the presence of few-walled CNTs could enhance electrical conductivity and specific surface area without compromising the loading of active materials.

Empirical modeling of normal/cyclo-alkanes pyrolysis to produce light olefins

Due to the complexity of feedstock, it is challenging to build a general model for light olefins production. This work was intended to simulate the formation of ethylene, propene and 1,3-butadiene in alkanes pyrolysis by referring the effects of normal/cyclo-structures. First, the pyrolysis of n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, cyclohexane, methylcyclohexane, n-hexane and cyclohexane mixtures, and n-heptane and methylcyclohexane mixtures were carried out at 650–800 °C, and a particular attention was paid to the measurement of ethylene, propene and 1,3-butadiene. Then, pseudo-first order kinetics was taken to characterize the pyrolysis process, and the effects of feedstock composition were studied. It was found that chain length and cyclo-alkane content can be qualitatively and quantitively represented by carbon atom number and pseudo-cyclohexane content, which made a significant difference on light olefins formation. Furthermore, the inverse proportional/quadratic function, linear function and exponential function were proposed to simulate the effects of chain length, cycloalkane content and reaction temperature on light olefins formation, respectively. Although the obtained empirical model well reproduced feedstock conversion, ethylene yield and propene yield in normal/cyclo-alkanes pyrolysis, it exhibited limitations in simulating 1,3-butadiene formation. Finally, the accuracy and flexibility of the present model was validated by predicting light olefins formation in the pyrolysis of multiple hydrocarbon mixtures. The prediction data well agreed with the experiment data for feedstock conversion, ethylene yield and propene yield, and overall characterized the changing trend of 1,3-butadiene yield along with reaction temperature, indicating that the present model could basically reflect light olefins production in the pyrolysis process even for complex feedstock.

Sensitivity of additively manufactured AA7075 to variation in feedstock composition and print parameters

We developed a combined finite element and CALPHAD based model of the Laser Powder Bed Fusion (LPBF) process for AA7075 alloy that considers the effect of feedstock composition and print parameters. A single-pass of a laser on a layer of AA7075 alloy powder has been considered. Sensitivity of temperature evolution and melt pool geometry to variation in the stoichiometry of the feedstock powder and laser source characteristics have been studied. Our results indicate that deviation (up to 10%) of the feedstock composition from the AA7075 raises the maximum temperature and increases melt pool size. Excess Cu content shows the largest melt pool width and depth among all the cases. The peak temperature is higher than the standard feedstock composition in all cases, except when the Cu concentration is reduced. Increasing the scan power also results in a higher peak temperature and a larger melt pool size. Furthermore, the temperature's rise time increases by lowering the scan speed.

Leachate after aerobic stabilization of municipal solid waste supplemented by waste glycerine from saponification to improve biogas production during co-digestion

Co-digestion of leachate from aerobic stabilization of OFMSW (leachateOFMSW) with waste glycerine (WG) from saponification is a promising approach for municipal waste and wastewater treatment. The effect of feedstock composition on co-digestion efficiency was examined. Two feedstocks with different contents of WG (6%, 13%) were used, which affected the COD:TKN ratios in those feedstocks (60, 100). LeachateOFMSW provided nitrogen and the micro- and macroelements. In both feedstocks, the N–NH4:TKN ratio was low (0.08), indicating that the dominant form of nitrogen was organic nitrogen (Norg). Co-digestion was carried out in upflow anaerobic-sludge blanket reactors (37 ± 2 °C; OLR, 4 kg COD m−3 d−1).This process ensured highly effective COD removal (over 97%). At a feedstock COD:TKN ratio of 60, specific biogas production (SBP) was ca. 0.22 m3 kg−1 COD, and methane content, 61.6%. Increasing the COD:TKN ratio to 100 significantly increased SBP to ca. 0.36 m3 kg−1 COD, but reduced biogas quality (54.2% CH4). Although Norg had to be ammonified to ammonium because of the low N–NH4:TKN ratio in the feedstocks, the ammonium concentration in the post-processing wastewater remained low. Moreover, the low ammonium concentrations meant that the pH (8.8) did not have a toxic effect on anaerobic co-digestion (free ammonia concentrations were merely ca. 28 and 5.5 mg L−1, respectively). However, at higher feedstock COD:TKN ratios than those tested, ammonium could be exhausted, which would impede methane production. These results indicate that WG is an effective co-substrate for leachateOFMSW if an appropriate amount of WG is added to the feedstock.

Crude to Olefins: Effect of Feedstock Composition on Coke Formation in a Bench-Scale Steam Cracking Furnace

A novel experimental unit has been designed, allowing the examination of the fouling tendency in all relevant sections of a steam cracking furnace, that is, dry feed preheater (DFP), dilute feed pr...

Hydrothermal liquefaction of low-lipid algae Nannochloropsis sp. and Sargassum sp.: Effect of feedstock composition and temperature

Low-lipid content algae have demonstrated potential in the bio-crude production because of their high yield and robust ability to adapt to hostile cultivation environment in mass cultivation. Hydrothermal liquefaction (HTL) technology is an effective method to convert wet algae to bio-crudes directly. In this study, the HTL processes of two low-lipid content algae, Nannochloropsis sp. and Sargassum sp., were investigated under various reaction temperatures (260–320 °C). Results showed that the bio-crudes yield of Nannochloropsis sp. (39.05 wt% to 54.11 wt%) was significantly higher than that of Sargassum sp. (3.11 wt% to 9.49 wt%). The higher heating value of Nannochloropsis sp. (35.92 MJ/kg to 37.88 MJ/kg) were also slightly higher than that of Sargassum sp., (33.63 MJ/kg to 35.23 MJ/kg). GC–MS analyses showed that Nannochloropsis sp. bio-crude mainly contained amides and N-heterocyclic compounds while Sargassum sp. bio-crude mainly contained N-heterocyclic compounds and ketones. Alcohols were the major aqueous phase compounds for both algae. For Nannochloropsis sp., glycerin accounted for the largest proportion in alcohols, while dianhydromannitol and 1,5-anhydro-d-mannitol were the major alcohols component for Sargassum sp. Based on the compositions of the HTL products and the feedstock, a reaction pathway network of the HTL process of low-lipid algae was proposed in this study. Amino acids related interactions like acylation and Maillard reaction were prominent in HTL process of these two algae, which effectively converted protein and carbohydrate compounds into bio-crudes.

The effect of feedstock composition on fast pyrolysis and upgrading to transportation fuels: Techno-economic analysis and greenhouse gas life cycle analysis

Process economics and greenhouse gas (GHG) emissions are evaluated for the conversion of eleven (11) biomass feedstocks to produce transportation fuels via fast pyrolysis and then pyrolysis oil upgrading via hydrodeoxygenation. The biomass consists of six (6) pure feeds (pine, tulip poplar, hybrid poplar, switchgrass, corn stover, oriented strand board) and five (5) blends. Feedstock blends combine pine, tulip poplar, hybrid poplar, switchgrass, and oriented strand board in various ratios. The assumptions used in this analysis are based on a unique experimental data set. They are “field to wheel” data generated from a multistep experiment that started from biomass preparation and was followed by biomass feedstock conversion to pyrolysis oil, and then finished by pyrolysis oil upgrading to produce hydrocarbon liquid fuel. Process economic results are reported in US dollars per gasoline gallon equivalent (gge) at the minimum fuel selling price (MFSP). For all eleven feedstocks, the largest cost contribution to MFSP is capital-related costs, which is approximately 30%–40% of the MFSP and includes capital depreciation, income tax, and return on investment. Feedstock cost (approximately 30% of MFSP), hydrotreating catalyst cost (13%–18% of MFSP) and labor cost (12%–15% of MFSP) also contribute significant cost to MFSP. Final fuel product yield is one of the most significant parameters affecting the process economics. The highest product yield is from pine feedstock, while switchgrass feedstock gives the lowest yield. Using blends (woody mixed with herbaceous), with which the product yield is still reasonable, may further improve process economics compared to pure feedstocks because of the lower feedstock price for blends. Blend feedstocks cost less than pure feedstock because of greater diversity in feedstock choices, lower risk, and lower transportation costs. GHG reduction does not necessarily align with favorable economics. Process parameters that most significantly affect the life cycle GHG emissions (from feedstock production to vehicle operation) are (1) natural gas used for hydrogen production and electricity usage in fast pyrolysis and pyrolysis oil upgrading, (2) energy usage in the feedstock harvesting, transport, and preprocessing operations, and (3) nitrogen fertilizer usage for growing biomass.

Characterization and ecotoxicological investigation of biochar produced via slow pyrolysis: Effect of feedstock composition and pyrolysis conditions

This study systematically investigated the biochar toxicity from the in vitro tests involving the use of human liver and lung cell lines, as well as in vivo tests using Drosophila melanogaster (fruit fly). Biochars used in this study were produced from vegetable waste, pine cone and their mixture (1:1 by weight) at two representative temperatures (200 and 500 °C). Two common toxicant groups in biochar, heavy metals (HM) and polycyclic aromatic hydrocarbons (PAHs) contents, were detected for clarification of the relationship between their toxicity behaviors and biochar bulk characteristics. The results showed that (1) no HMs can be found in the biochar if HMs are absence in their feedstock (2) PAHs were formed during the pyrolysis no matter what type of biomss used, but the concentration is low that can be acceptable for soil legislative criteria (3) biochars had limited impact to the viability of flies, but inhibited the growth of the cells (4) the low leaching potential of HMs and PAHs (total 16 USEPA) in the studied biochars may not be the major reason which put the harm to the cell, more effort on the identification need to be done. This work can provide a new picture to the biochar researchers for better understanding of the two faces of biochar.

Process modeling of hydrodeoxygenation to produce renewable jet fuel and other hydrocarbon fuels

The focus of this work is to model the hydrodeoxygenation process to produce renewable jet fuel and co-products from low-input oilseeds, specifically camelina, carinata (non-edible oil) and used cooking oil (UCO), taking into account the fatty acid compositions by incorporating the stoichiometric hydrodeoxygenation reactions. This methodology provides insight into the effect of feedstock composition and hydrodeoxygenation reactions upon product yields, product distribution, hydrogen consumption and process utilities. The resulting product slates, hydrogen gas and utility demands are specific to each of the camelina, carinata and UCO feedstocks.The yield of kerosene-range alkanes ranged from 53 to 54% of the incoming oil, with 13–14% diesel range alkanes, 13–15% naphtha, and 7–9% liquefied petroleum gas, depending upon the fatty acid composition. The hydrogen consumption rate ranged from 26 to 30kg per tonne of incoming oil, depending upon the degree of bond unsaturation. Thermal energy demand is 2.8GJ/tonne oil when processing used cooking oil, versus 5.2 and 5.7GJ/tonne of oil for carinata and camelina, respectively, owing to the additional energy required for oil extraction. Electricity demand was 73kWh/tonne oil for UCO, versus 170 and 227kWh/tonne oil for carinata and camelina.

Pyrolysis Oil Multiphase Behavior and Phase Stability: A Review

This paper reviews the literature related to the complex chemical composition and multiphase nature of bio-oils and their practical implications. Over time, bio-oil forms separated phases due to purely physical phenomena (phase stability) or chemical composition changes in storage (aging reactions). Bio-oil multiphase behavior and the formation of separated phases are controlled by the complex chemical composition of these oils. Fast pyrolysis oils from woody biomass are typically observed in a single phase. However, feedstocks with high extractives content and/or high ash content commonly produce oils with more than one phase (an aqueous phase, an upper layer, and a decanted heavy oily phase). The first part of this Review focuses on the effects of feedstock composition, particle size, type of pyrolysis reactor, and condensation systems on bio-oil chemical composition and their impact on stable oils production. The second section reviews our current understanding of fresh bio-oil multiphase behavior and the effect of aging reactions. The use of phase diagrams as a tool to predict bio-oil phase stability is discussed. The third section focuses on bio-oil upgrading strategies based on the use of solvents and the production of emulsions. In this section we discuss the factors affecting phase equilibrium. This review highlights the importance of developing systematic studies to better understand bio-oil liquid–liquid phase equilibrium and the advantages of using phase diagrams. This understanding could have significant impact on the development of new bio-oil separation processes, on the development of new tools to produce stable bio-oils, as well as on the production of bio-oil-derived fuels. Understanding the complex nature of bio-oil multiphase behavior has been progressing over the years; however, more work is still needed to control these phenomena.

Supercritical water gasification of Eucalyptus grandis and related pyrolysis char: Effect of feedstock composition

Eucalyptus grandis (E. grandis) wood and char products derived from pyrolysis of E. grandis wood, were gasified in supercritical water at 450°C – with and without the use of a homogeneous (K2CO3) and heterogeneous (Ni/Al2O3-SiO2) catalyst. Gas yields and gasification efficiencies were measured experimentally and compared to calculated thermodynamic equilibrium values, specifically considering the effects of the O/C ratio and volatile matter content of the feed material. Thermodynamically, feed material with lower O/C ratios (0.22) typically resulted in higher CH4 yields (30mol/kgfeed,dry) and gasification efficiencies (188%). However, experimentally, feed material with lower O/C ratios and lower volatile matter resulted in the lowest CH4 yields and gasification efficiencies. Furthermore, a linear relationship between the carbon efficiency (CE) and both the volatile matter content and O/C ratio of the feed material was found to hold true in both catalytic and non-catalytic experiments.

The effect of feedstock composition and taxonomy on the products distribution from pyrolysis of nine herbaceous plants

The effect of feedstock composition and taxonomy on the products distribution from pyrolysis of nine herbaceous plants was evaluated. Specifically, eight members of the Poaceae family and one member of the Fabaceae family were pyrolyzed in a fixed bed reactor to a final temperature of 700°C. All samples resulted in a medium-energy CO2-rich gas and a phenol-rich liquid. The type of lignin rather than the overall lignin content was found to influence the phenols yield. All samples produced char with a suitable C/N ratio; eight plants produced char with high polarity; and only one sample (i.e., mountain brome) resulted in char with a sufficient aromaticity to be applied to soil. Low carbonization was associated with a high content of inorganic elements that were most likely deposited on the char's surface and blocked vaporization. The product distributions were dependent on (i) chemical and biochemical composition of feedstock, (ii) secondary reactions of liquid and char, and (iii) the samples' taxonomy. Red clover from the Fabaceae family was found to be the most distinct, followed by mountain brome from the Triticodae group (Poaceae family), and the remaining members of the Poodae group (Poaceae family). The least divergence was found between the hybrid samples.

Hydrothermal liquefaction of macro algae: Effect of feedstock composition

Due to the increasing thrust on third generation biofuels, algal research has gained a lot of importance in the recent years. Effective utilization of algal biomass in a single step is necessary as it can produce fungible hydrocarbons in addition to a variety of valuable products.Hydrothermal liquefaction does not require the energy intensive drying steps and is an attractive approach for the conversion of algae which has high moisture content. The objective of this study is to understand the effect of compositional changes of macro algae samples Ulva fasciata (MA’UF), Enteromorpha sp. (MA’E) and Sargassum tenerrimum (MA’ST) on product distribution and nature of products. Various macro algae samples were converted to bio-oil by hydrothermal liquefaction in a batch reactor at 280°C for 15min with biomass:water ratio of 1:6. The liquefaction products were separated into ether soluble fraction (bio-oil1), water-soluble fraction, solid residue and gaseous fraction. Maximum conversion of 81% was observed with macro algae (MA) UF. The effect of varying feedstock compositions were reflected in the bio-oil and bio-residue yields. The maximum conversion and bio-oil yield was observed with MA’UF due to the presence of higher carbohydrate content than other feeds. FTIR and NMR spectra showed high percentage of aliphatic functional groups for all bio-oils.

Performance Prediction of the Catalyst PR-81 at the Production Unit Using Mathematical Modeling Method

The performance analysis of the reforming catalyst PR-9 and its replacement prediction on the catalyst PR-81for production reforming unit L-35-11/450K have been carried out using a mathematical model. The effect of feedstock composition on product yield has been studied. It is shown that the feedstock composition decisively influences the yield and octane number. The model study have shown that the replacement for the PR-81 catalyst will increase the yield of 2.5-3.5% wt.

Pyrolysis of North-American grass species: Effect of feedstock composition and taxonomy on pyrolysis products

In the Midwest of the U.S., several members of the Poaceae family can be grown as bioenergy crops. Besides Miscanthus and switchgrass, which have been extensively studied, native Midwestern grasses such as big bluestem, coastal panicgrass, deertongue, indiangrass, sandreed and sideoats grama can be grown in monoculture or polyculture plantations. In addition to climate, soil fertility and water availability, the selection of bioenergy crops depends on the choice of conversion technology. One such technology, fast pyrolysis, is a thermochemical approach for converting biomass into a liquid product known as bio-oil, a hydrocarbon fuel intermediate. In this research, the eight aforementioned grass varieties were characterized by fiber and metal analyses as well as calorimetry and thermal gravimetry. Conversion by analytical pyrolysis showed that although variability exists, all eight grasses produced a similar spectrum of chemical compounds. Principal component analysis of pyrolysis-GC/MS data detected statistically significant differences amongst the grass varieties on the basis of six key chemical markers: glycolaldehyde, acetic acid, acetol, methyl glyoxal, 4-vinylphenol and levoglucosan. Though taxonomic classification was not found to affect product composition, correlation analysis verified that biomass composition and thermal properties might be responsible for the differences in pyrolysis products.

Effect of feedstock composition and organic loading rate during the mesophilic co-digestion of olive mill wastewater and swine manure

In the present study, the optimisation of the mesophilic anaerobic co-digestion process of olive mill wastewaters (OMW) together with swine manure (SM) was investigated. Batch and continuous mode experiments were performed in order to define the most efficient mixing ratio and to determine the performance of the reactors under different organic loading rates (OLR). In batch experiment, the most efficient mixing ratio consisted of 40% OMW and 60% SM, since it presented the highest methane production equal to 277 mL CH4/g COD, which corresponded to 79% of the theoretical yield. It was found that the effectiveness of this mixing ratio was not affected in the continuous operation of the reactors. The stepwise increase of the OLR did not affect negatively biomethanation, although the concentration of the inhibitory compounds of the OMW was higher. Under OLR of 4.4 g volatile solids/(L-feed·day) the methane yield of the reactors fed with 40% OMW reached 373 mL CH4/gVS (78% of the theoretical yield). The findings of the present study proved that the co-digestion of OMW together with SM is a sustainable solution, capable to efficiently treat simultaneously these residual residues.

EFFECT OF FEEDSTOCK, ORGANIC MATTER CONTENT AND PH ON CD, ZN AND MN AVAILABILITY IN FARM COMPOST BASED ON BARK AND WOOD CHIPS

We aimed to determine the effect of feedstock composition on Cd, Zn and Mn concentrations and availability during the composting process for small-scale composting. The effect of using wood chips instead of tree bark on compost properties was determined in a compost trial with leek residues and hay of grass included in the feedstock. Supplementary experiments included sequential extraction for determining the easily exchangeable, reducible, oxidizable and residual fractions for Cd, Mn, and Zn in composts. We determined the effect of decreasing the pH or the organic matter content and adding easily available Zn and Mn on the fractionation and availability of Cd, Mn and Zn in composts. Use of bark or wood chips resulted in elevated Cd, Zn or Mn concentrations in the compost. Cd concentrations in the compost may exceed legal criteria, mainly due to the use of wood chips or bark of tree species with high Cd uptake. Based on sequential extractions, we measured that Cd and Zn were mainly bound in the reducible fraction, while Mn was found in the easily available fraction. Even at higher total Cd and Zn concentrations in the composts, the results of the sequential extractions showed a small fraction which is present in the exchangeable fraction, which indicates a low environmental risk when applying these composts. Higher Cd concentrations in compost due to the use of bark or wood chips were not found to result in higher risk for Cd leaching. The results of pH-stat experiments illustrated that only a strong pH decline in the compost resulted in higher availability of Cd, Zn and Mn. The amount of soil in the feedstock material or unintentionally added during the composting process affected total and available concentrations for Mn.

DESIGNER COMPOST: FACTS OR FANTASY? A CASE STUDY ON COMPOST RICH IN LIGNIN AND LOW IN PHOSPHORUS

Application of compost as a source of stabilized organic matter is one strategy for increasing the organic carbon content of arable land. To meet environmental standards on nutrient leaching, especially the total P content of the composts limits the application rate. A functional compost with high lignin content and low P concentration would be a valuable tool for maintaining soil fertility. We aimed to determine the effect of feedstock composition on P and lignin content in compost. The research is based on three farm compost experiments with three treatments each, and three compost experiments in nature conservation areas. Besides general characteristics, lignin and ergosterol content and total P and N concentrations were measured in the composts. A 12-week incubation experiment was set up to measure N mineralization and P release by the composts when applied to the soil. In general, compost characteristics varied due to differences in feedstock and composting process characteristics. The produced farm composts had higher organic matter contents than the other composts; by feedstock selection farm composts with a total P content lower than 3 g P/kg dry matter were produced. The lignin content for the organic part of the compost was relatively constant for different compost types. The incubation experiments indicated that the effect on P availability in soil was strongly related to changes in soil pH after compost addition. Our results indicate that total P concentration of the feedstock materials should always be assessed in combination with mass reduction of the feedstock mixture during the composting process.

Effect of feedstock composition on product yields and energy recovery rates of fast pyrolysis products from different straw types

The conversion of different types of straw by fast pyrolysis has been investigated in this study. The mass and energy balance for corn stover, wheat straw and also rape and sunflower stalks are reported. A process development unit with a twin screw mixer reactor has been utilised for the experiments with a feeding rate of 10kg/h at fixed operation conditions of reactor temperature, cooling temperature, vapour residence time, biomass particle size and heat carrier material. The results in product yields and energy recovery rates are compiled and compared. It can be observed that different types of straw produce different char, condensate and gas mass yields due to their varying ash content and differing lignocellulosic composition. On a dry and ash-free basis elemental formulas for feedstock, char, organic condensate and gas could be defined independent of the feedstock due to similar elemental compositions. Gas flow rate and composition measurements provide additional information on mass yields: a CO/CO2-ratio of 1 (i.e. wood) corresponds to an organic condensate yield of about 50wt.%, whereas a ratio of 0.3–0.7 (straw) corresponds to about 18–32wt.%.