Yield Of Liquefaction Products Research Articles

Bio-oil recovery from olive mill wastewater in sub-/supercritical alcohol-water system

Olive mill wastewater was converted into bio-oil via thermochemical liquefaction with alcohol/water mixtures in an autoclave (998 ml). The influence of operating conditions on the yield of liquefaction products was investigated. Liquefaction experiments were performed at various reaction temperatures in the range of 240–320 °C. Experimental results indicated that alcohol (methanol or ethanol)/water mixtures had synergistic effects on olive mill wastewater direct liquefaction. The ratio 50% (w/w) co-solvent of either ethanol-water or methanol-water and a reaction temperature of 280 °C were found to be the most effective. Under these conditions and for a reaction time of 30 min, the bio-oil yield was 92.31 wt% for ethanol-water and 77.97 wt% for methanol-water. The bio-oil produced with methanol-water mixture has higher energy content (43.20 MJ/kg) compared to the one obtained with ethanol-water mixture (39.21 MJ/kg). In addition, Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry analyses showed high esters concentrations and low free fatty acid content in the obtained bio-oils.

Alkaline hydrothermal liquefaction of swine carcasses to bio-oil

It is imperative that swine carcasses are disposed of safely, practically and economically. Alkaline hydrothermal liquefaction of swine carcasses to bio-oil was performed. Firstly, the effects of temperature, reaction time and pH value on the yield of each liquefaction product were determined. Secondly, liquefaction products, including bio-oil and solid residue, were characterized. Finally, the energy recovery ratio (ERR), which was defined as the energy of the resultant products compared to the energy input of the material, was investigated. Our experiment shows that reaction time had certain influence on the yield of liquefaction products, but temperature and pH value had bigger influence on the yield of liquefaction products. Yields of 62.2wt% bio-oil, having a high heating value of 32.35MJ/kg and a viscosity of 305cp, and 22wt% solid residue were realized at a liquefaction temperature of 250°C, a reaction time of 60min and a pH value of 9.0. The bio-oil contained up to hundreds of different chemical components that may be classified according to functional groups. Typical compound classes in the bio-oil were hydrocarbons, organic acids, esters, ketones and heterocyclics. The energy recovery ratio (ERR) reached 93.63%. The bio-oil is expected to contribute to fossil fuel replacement in stationary applications, including boilers and furnaces, and upgrading processes for the bio-oil may be used to obtain liquid transport fuels.

The effects of cornstalk addition on the product distribution and yields and reaction kinetics of lignite liquefaction

The cornstalk-assisted direct lignite liquefaction was conducted by using a resonance agitation micro-autoclave heated by a salt bath. The effects of reaction temperature (360°C, 390°C, and 420°C) and time (5min, 15min, 30min, and 60min) on the distribution and yields of liquefaction products (asphaltene, preasphaltene, oil, and gas) were investigated. The results show that the reaction temperature has significant effect on the distribution and yields of products in the cornstalk-assisted direct coal liquefaction. At 360°C, the reaction from preasphaltene to asphaltene is the rate-limiting step of the overall co-liquefaction process, while at 420°C the reaction from asphaltene to oil becomes the rate-limiting step. A kinetic model is proposed and the kinetics analysis shows that the activation energy for the reaction from raw material to preasphaltene and asphaltene is 41.9kJ/mol, while that for the reaction from preasphaltene and asphaltene to oil and gas is 61.4kJ/mol. The addition of cornstalk can considerably improve the reaction kinetics of the co-liquefaction of Shengli coal and cornstalk.

Thermochemical liquefaction of rice husk for bio-oil production with sub- and supercritical ethanol as solvent

Rice husk was converted into bio-oil via thermochemical liquefaction with ethanol as solvent in an autoclave (500mL). The influences of reaction parameters on the yields of liquefaction products were investigated. Liquefaction experiments were performed at various reaction temperatures (T, 513–633K), solid–liquid ratios (R1, 5–15%), and solvent filling ratios (R2, 10–30%) with or without catalyst. Two types of catalysts were involved, including iron-based catalysts (FeSO4 and FeS) and alkali metal compounds (NaCO3 and NaOH). The dosage of catalyst (R3) was also optimized. Without catalyst, the bio-oil yields ranged from 11.8% to 24.2%, depending on T, R1 and R2. And the bio-oil yields increased firstly and then decreased with increasing T and R2, while the bio-oil yields continuously declined with increasing R1. NaOH was certified to be an ideal catalyst for rice husk liquefaction and the optimal dosage was approximately 10%. The obtained bio-oils had much higher caloric values of 20.9–24.8MJ/kg compared to 14.9MJ/kg for the crude rice husk sample. Without catalyst, the main components of bio-oil were phenolic compounds. In the case of NaOH as catalyst, long-chain alkanes were the major compositions of bio-oil.

Hydrothermal Liquefaction of Macroalgae Enteromorpha prolifera to Bio-oil

Marine macroalgae Enteromorpha prolifera, one of the main algae genera for green tide, was converted to bio-oil by hydrothermal liquefaction in a batch reactor at temperatures of 220−320 °C. The liquefaction products were separated into a dichloromethane-soluble fraction (bio-oil), water-soluble fraction, solid residue, and gaseous fraction. Effects of the temperature, reaction time, and Na2CO3 catalyst on the yields of liquefaction products were investigated. A moderate temperature of 300 °C with 5 wt % Na2CO3 and reaction time of 30 min led to the highest bio-oil yield of 23.0 wt %. The raw algae and liquefaction products were analyzed using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, gas chromatography−mass spectrometry (GC−MS), and 1H nuclear magnetic resonance (NMR). The higher heating values (HHVs) of bio-oils obtained at 300 °C were around 28−30 MJ/kg. The bio-oil was a complex mixture of ketones, aldehydes, phenols, alkenes, fatty acids, esters, aromatics, and nitrogen-containing heterocyclic compounds. Acetic acid was the main component of the water-soluble products. The results might be helpful to find a possible strategy for use of byproducts of green tide as feedstock for bio-oil production, which should be beneficial for environmental protection and renewable energy development.

Liquefaction reactivity and 13C-NMR of coals rich in barkinite and semifusinite

Coals rich in barkinite and semifusinite were selected to study their liquefaction behavior and chemical structure and to find correlations between the liquefaction product yield and chemical structural parameters. The liquefaction tests were carried out using tubing-bomb reactors in a preheated sand bath. The samples were characterized by ultimate analysis, proximate analysis, petrographic analysis, and 13C-NMR analysis. The results show that barkinite-rich samples contain high hydrogen and volatile matter contents and have high H/C atomic ratios. The chemical structures of the samples used are rich in aromatic carbon. WEST coal had the highest aromaticity. The content of methylene carbons is higher than content of methyl carbon of Leping (LP), Changguang (CG), and Dahebian (DHB) coals and also higher than that in the other three coal samples (YJL, P858, and WEST). The LP, CG, and DHB coals have higher liquefaction conversions and higher yields of oil. Definite correlations between the yield of oil and the content of methylene carbons and between liquefaction conversion and aromaticity have been observed, which indicates that the yield of liquefaction products can be predicted based on the solid-state 13C-NMR spectral data of coal.

Liquefaction of corn distillers dried grains with solubles (DDGS) in hot-compressed phenol

The present work aims to liquefy corn Distillers Dried Grains with Solubles (DDGS), a by-product in corn ethanol production, to produce liquid products as a potential substitute for petroleum-derived phenol or an additive in the manufacturing of phenolic resins. Efficient liquefaction of DDGS has been realized with hot-compressed phenol at 200-450°C. Effects of liquefaction temperature, initial phenol/DDGS ratio (wt/wt), residence time, and catalysts on yields of liquefaction products, as well as characterizations of typical liquid and solid products, have been investigated. The yield of liquid products increased with temperature, while it peaked at around 300°C, due to condensation/cracking reactions of the liquid intermediates/products to form solid products (i.e., coke/char) at temperatures higher than 300°C. The liquid yield increased monotonically with the initial phenol/DDGS ratio for a specified treatment time and temperature. An increased residence time generally produced a lower yield of liquid products, and a higher yield of solid residue, which was likely due to the increased coke/char formation from liquid products for a prolonged residence time. The yield of liquid products reached a maximum of 97 wt% at 300°C for 5 min-operation with Phenol/DDGS of 2/1. K2CO3, Rb2CO3, and NaOH were found very effective catalysts for enhancing the liquid yields. The use of these catalysts resulted in a 25% relative increase in the liquid yields for 5 minute operation with Phenol/DDGS of 1/1 at 300°C.

A comparative experimental study on the liquefaction of wood

Aqueous liquefaction of Cunninghamia lanceolata, Fraxinus mandshurica, Pinus massoniana Lamb. and Populus tomentosa Carr. was carried out in an autoclave in the reaction temperature range of 553.15–633.15 K, where both non-catalytic and catalytic liquefaction were performed. The experimental results show that the lignin content has a large effect on the yield of liquefaction products in the non-catalytic liquefaction. The addition of K 2CO 3 as a catalyst can significantly reduce the residue yield for all the woods tested, while its effect on the heavy oil yield becomes weaker with decreasing amounts of lignin. The present study shows that a heavy oil yield of 30% coupled with a residue yield of less than 10% can be obtained for all the wood samples tested in the catalytic liquefaction.

Prediction of coal liquefaction reactivity by solid state 13C NMR spectral data

A method for the deconvolution of 13C NMR spectra of coals has been developed by using coal-like model compounds and various lithotypes separated from Yallourn brown coal which is rich in various types of oxygen-functional groups. The spectrum of coal was resolved into 24 peaks which were classified into nine types of carbon-functional group. This analytical method can be applied to all ranks of coal from lignite to anthracite. In addition, the liquefaction data of seven kinds of coal collected from five different countries were obtained by the operation of 1 t/d process support unit and 150 t/d pilot plant NEDOL process liquefaction plants. A good correlation was obtained for every reaction product between structural data derived from solid state 13C NMR spectra and liquefaction data of coals. This means that the yields of liquefaction products could be predicted from 13C NMR spectral data of coal.

Catalysis of coal conversion at mild temperatures

Many materials have been used or tested as catalysts for the direct conversion of coal to liquids. However, the factors which determine whether a particular substance will be an excellent, fair or poor catalyst, or an inhibitor, are still not understood. Most of the catalyst studies have been of empirical nature and neither the specific catalytic mechanisms nor the exact forms responsible for the catalytic effects observed have been elucidated. In studies on the catalytic action of Lewis acids for the liquefaction of coal, many properties of these materials were correlated. After testing more than eighty catalysts, only one property was found to directly correlate with the yield of liquefaction products in coal conversion experiments. This property was found to be the electronic softness of the Lewis acids studied. Results from mild liquefaction experiments on bituminous coal have been obtained and give insight into the reactions taking place and the moieties involved in most of the liquefaction reactions.