Combustion characteristics of solid waste biomass,oil shale,and coal

In this study, a developed two-dimensional mathematical model was used to represent the physical model of the combustion process of olive cake and date seed, and solve the governing equations using finite-volume method. The simulation was performed using ANSYS/Fluent software in order to estimate maximum temperature, heating values and pollutants concentrations. The obtained results were compared with experimental results, and corresponding values of oil shale and coal. The experimental work of direct burning of olive cake and date seeds was performed using an existing circulated fluidized bed (CFB) unit.

It was found that the adiabatic flame temperatures were 1380 K and 839 K for olive cake and date seed, and 2260 K and 1080 K for coal and oil shale, respectively. The experimental results showed that the maximum temperatures were 1126 K and 723 K for olive cake and date seed, respectively. The lower heating values were 19,500 kJ/kg and 16,400 kJ/kg for olive cake and date seed, and 29,000 kJ/kg and 7000 kJ/kg for coal and oil shale, respectively.

Thus, biomass such as date seed and olive cake may be used as an alternative fuel in electrical power plants in olive- or date-producing countries, which may save 40% of fuel cost.     

A process for producing carbonaceous matter from tar sand,oil shale and olive cake

Many countries which do not produce oil are rich with other sources of energy that are not fully utilized, such as tar sand, oil shale and olive cake. Limited previous work was done on producing carbonaceous matter and separating volatile matter from combinations of tar sand, oil shale and olive cake. In this study, a process is designed and tested to produce carbonaceous matter from combinations of the three materials mentioned above. Results indicate that the process is successful in producing carbonaceous matter. The minimum temperature to achieve complete carbonization was found to be 500°C for a minimum heating time of 1.5 h. Carbonized materials were tested for their calorific values, which indicated a successful carbonization process. The proposed process can be scaled up and automated, and is expected to be economically feasible. Moreover, the process allows for control of unwanted exiting polluting gases and volatile matter and therefore is environmentally safe.     

An experimental study for a combined system of tar sand, oil shale, and olive cake as a potential energy source in Jordan

Jordan is an example of a third world country that is non-oil producing but contains huge reserves of other energy sources such as tar sand, oil shale, and olive cake. Some limited research is available about how to utilize these energy sources in pure form. However, available research does not deal with combinations of these energy sources. This experimental study investigates combinations of these energy forms as potential energy sources in Jordan. The experimental procedure involves characterization of samples by proximate analysis, calorific value determination of different combinations, and a compacting process of the different particles. The best combination, with respect to calorific value, is found to be 20% tar sand, 20% olive cake, and 60% oil shale. Compacting materials either with starch or with heated tar sand up to 110°C for 1 h indicates a feasible process for handling, packaging, and transporting.     

Bitumen recovery from Jordanian oil sand by froth flotation using petroleum cycles oil cuts

Jordan has huge reserves of energy sources such as oil sand, oil shale, and olive cake. This work presents a part of an ongoing project to develop an appropriate low cost beneficiation technology for Jordanian oil sand. This study presents the utilization of a modified fluidized froth flotation process for beneficiation and bitumen recovery from Jordanian oil sand. This modification includes fluidization technology to replace the agitation process found in a typical flotation technology. Results of this research show that the recovery of bitumen from Jordanian oil sand reaches its maximum of 86% during the addition of 0.35 wt% of a special cut of light cycle oil as a collector. The results show that the amount of hydrocarbon content (H.C) in oil sand has a minimal impact on floatability of oil sand. In addition, the results show that increasing the temperature enhances the bitumen recovery from Jordanian oil sand. The addition of NaOH is found to have a similar effect of increasing bitumen recovery. The results show that a special cut of cycle oil increases the bitumen recovery more than the normal cut of cycle oil.     

Flash pyrolysis of jatropha oil cake in electrically heated fluidized bed reactor

Fluidized bed flash pyrolysis experiments have been conducted on a sample of jatropha oil cake to determine particularly the effects of particle size, pyrolysis temperature and nitrogen gas flow rate on the pyrolysis yields. The particle size, nitrogen gas flow rate and temperature of jatropha oil cake were varied from 0.3 to 1.18 mm, 1.25 to 2.4 m³/h and 350 to 550 °C. The maximum oil yield of 64.25 wt% was obtained at a nitrogen gas flow rate of 1.75 m³/h, particle size of 0.7–1.0 mm and pyrolysis temperature of 500 °C. The calorific value of pyrolysis oil was found to be 19.66 MJ/kg. The pyrolysis gas can be used as a gaseous fuel.     

Producing Bio-oil from Olive Cake by Fast Pyrolysis

Abstract

This article reports on physico-chemical properties of olive cakes to evaluate them as a raw material in energy production through thermo-chemical pyrolysis conversion process. The present study focuses on the actions related to the possibilities to utilize in particularly olive cake as an agricultural residue. Olive cake is a very promising material for the production of bio-oil. Liquid, solid, and gaseous products were obtained from olive cake by pyrolysis. If the purpose were to maximize the yield of liquid products resulting from biomass pyrolysis, a low temperature, high heating rate, and short gas residence time process would be required. Flash pyrolysis gives high oil yields. The heating was carried out from 298 K to 1,050 K in the absence of oxygen. The yields of liquid products were obtained from the olive cake by pyrolysis for the runs of different heating rates: 10 K/s, 20 K/s, and 40 K/s. The highest bio-oil yields from the olive cakes were 31.0% at 700 K, 36.0% at 700 K, and 41.0% at 700 K obtained from 10 K/s, 20 K/s, and 40 K/s heating rate runs, respectively. The highest bio-oil yields olive stone shells were 27.0% at 700 K, 31.0% at 700 K, and 34.5% at 750 K obtained from 10 K/s, 20 K/s, and 40 K/s heating rate runs, respectively.     

Studies of the effect of retorting factors on the yield of shale oil for a new comprehensive utilization technology of oil shale

The comprehensive utilization of oil shale is a new promising technology achieving high utilization-factors for both oil shale’s chemical and energy potentials, and avoiding serious environmental impacts. For this technology, it is an urgent issue how to obtain shale oil with a high yield and as well as treat shale char efficiently and economically. In this present work, retorting experiments of three type I oil shales were performed using an aluminum retort, and the effect of retorting temperature, residence time, particle size and heating rate on the yield of shale oil was studied at low retorting temperatures ranging from 400 °C to 520 °C, respectively, at which shale char obtained has good combustion properties. The experimental data show that an increase in the retorting temperature, the residence time and the heating time has positive significant effect on improving the yield of shale oil, and a middle particle size is helpful for increasing the oil yield as well. The grey system method was applied to evaluate the effect of retorting factors on the yield of shale oil, showing that the retorting temperature is the most marked factor influencing the yield of shale oil.     

Thermal cracking combined with supercritical fluid extraction of Jordanian oil shale

In this work, supercritical extraction of Jordanian oil shale was investigated experimentally using a batch autoclave device. Operating conditions such as solvent type, mixing time, temperature, pressure, and particle size effects on oil recovery from oil shale have been studied. The results indicated that oil yield increases with the increase of pressure and temperature. The maximum extract yields of 15 and 16 wt% were obtained at 42 bars and 318°C with toluene for El-Lajjun and Sultani shales, respectively. Supercritical fluid extraction (SFE) has shown to be an efficient technique since the extracted yield was 55% more than the yield obtained using the classical Fischer Assay retorting process.     

Evaluation of oil yield from Jordanian oil shales

In this paper, the influences of particle size, grade and pyrolysis temperature on the oil yield have been evaluated in a laboratory scale reactor. Five categories of particle sizes from two different oil shale samples were pyrolyzed by employing a fixed bed retorting system. The reactor and the oil shale sample were heated at a constant rate and nitrogen gas was used to purge the sample, continuously, in order to remove the pyrolysis products from the reactor as well as to reduce secondary reactions. The liquid products were condensed and collected in a series of cold glass-traps and the off-gases analysed for their hydrocarbon and non-hydrocarbon species. Subsequent experiments were carried out, employing a thermogravimetric analyser, using only the four smallest particle sizes under similar conditions as applied to the fixed bed retort. The activation energy was determined by using the integral method. The pyrolysis of the investigated shales was found to comply with first-order kinetics within the limits of experimental error. Increasing the particle size resulted in a small rise in the liquid oil yield, but simultaneously the total gaseous production was decreased.     

Flame propagation behaviors and influential factors of TiH2 dust explosions at a constant pressure

The flame propagation through TiH₂ dust cloud at near constant pressure condition is studied in a series of experiments using an apparatus with transparent latex balloons. The influential factors for the combustion performance of TiH₂ dust cloud, including dust concentration, particle size, scale of isobaric space and oxygen content are investigated. Results show that the burning velocity increases with dust concentration in the fuel-lean mixtures, and then plateaus after crossing the stoichiometric condition, while the trend of flame speed changing with dust concentration varies for different mean particle sizes (D₅₀) of 48 and 106 μm. The flame propagation speed of dust cloud is positively correlated to the isobaric space scale and oxygen content. The burning mechanism of TiH₂ dust is thought to be mainly controlled by diffusion regime, the appearance of hydrogen gas accelerates the combustion rate of TiH₂ particles and also makes the TiH₂ dust changed from a discrete media to a continuum, which may account for the phenomenon that the flame speed in dust cloud of TiH₂ is larger than that of Ti at the same concentration no matter in air or oxygen atmosphere.     

Olive Cake as a Biomass Fuel for Energy Production

Olive cake (OC) is a by-product of olive oil production and is a solid material consisting of seed particles and the fleshy parts of olive. The Mediterranean region represents 98% of the world's olive tree population, and Turkey is among the top five main olive oil producer countries around the world. The main objective of the present study is to investigate the potential and utilization of olive cake (OC) in the country. It is estimated that over 360,000 tons of OC, corresponding to an average of 150,000 tons of oil equivalent (toe), were produced in the season of 2000–2001 in Turkey. From the combustion experiments performed in the conventional OC-fired boilers in the country, the values for CO-emissions were found to vary from 1,800 to 10,000 mg/m ³ . Suitable combustion systems, such as fluidized bed systems, stoker fed from the bottom with secondary air supply, etc., should be used for efficient energy production from the OC. Determination of values of the flue gas can be used in calculating for heating surfaces.     

Sulfur distribution in the oil fractions obtained by thermal cracking of Jordanian El-Lajjun oil Shale

The extracted shale oil by the thermal cracking process of the El-Lujjan oil shale showed that the yield of oil was around 12 wt%. The amount of sulfur in this shale oil was found to increase (from 7 to 9.5 wt%) with the increase of the boiling point for different distillate fractions. Sulfur in Jordanian oil shale was found to be mainly organic sulfur with negligible amounts of inorganic sulfur. Sulfur was found to be in the aromatic form in these fractions. Different forms of thiophenes were found in all fractions of the shale oil extracts without a distinct change in the concentration of any specific compounds with these extracts. Alkylthiophenes were the dominant phases in these fractions.     

Combined Process of Solvent Extraction and Gamma-Ray Radiation for the Extraction of Oil from Oil Shale

Abstract

Jordanian oil shale kerogen was studied by using several solvents under the gamma radiation condition to extract oil from shale. According to the result obtained, the possibility to extract oil at room temperature and using solvent was successfully obtained. The solvent used in this research study was water, benzene, acetone and kerosene. Experiments was conducted by using a mixture of solvents such acetone water, benzene-acetone, benzene-kerosene, and benzene, kerosene, water alone without mixing. The percentage of yield was found to be with in the range of 13–67. The result showed that acetone-water solvent mixture with 50% of each (vol%) gives the best results. In this study, the particle size was fixed at 1mm size since there was no effect size on extraction yield percentage.     

用直接数值模拟对移动颗粒层除尘的研究

利用气固两相流数值模拟计算模型 ,分别采用了不同粒径的移动颗粒层过滤除尘器 ,对不同粒径粉尘颗粒的碰撞次数进行统计 ,对移动床除尘中过滤介质尺寸与粉尘粒径尺寸之间的相互选择性进行了初步研究。模拟计算了在同一风速下碰撞次数与粉尘粒径以及移动层颗粒粒径之间的关系。计算统计的结果与实验结果对比发现 ,二者存在定性上的一致。研究结果表明在移动床过滤除尘器中不同粒径的过滤层对不同粒径尘粒具有明显的选择性。     

The chemistry of minerals obtained from the combustion of Jordanian oil shale

A characterization study was performed on the spent oil shale (oil shale ash) obtained from the combustion of Jordanian oil shale. This characterization utilized different analytical techniques. These include scanning electron microscope with energy dispersive spectrum analysis, X-ray fluorescence, X-ray diffraction and Qemscan. During the combustion process, minimal fragmentation was encountered since Jordanian oil shale contains large proportions of ash which maintain the original structure of the oil shale particle. Different analytical techniques confirmed that the dominant phase of minerals in the oil shale is calcite, which transforms, in parts, into anhydrite during combustion. Sulphur was found to be mainly of an organic source. This sulphur is combusted to produce SO₂ and then SO₃, which controls the sulphation reaction of the calcite. The dominant phase in the ash was the anhydrite in addition to the calcite, clays and calcium phosphate.     

A comparison of ignition characteristics of slurry fuels prepared using coal processing waste and finely divided coal

The scientific novelty of the research is that for the first time differences in the conditions and characteristics of the ignition and burning of droplets of slurries prepared on the basis of coals and waste from their enrichment have been established. The practical significance of the research results is that they illustrate the prospects of utilization of the numerous coal enrichment wastes by combustion in the composition of aqueous slurries with the generation of a rather large amount of energy and a relatively small negative environmental impact. The most significant characteristics were compared: the limiting (minimum) temperature; the ignition delay times; the maximum combustion temperature; the concentration of the main gas anthropogenic emissions. It has been found that fuel mixtures prepared from wet waste of coal flotation are characterized by higher inertia and ignition temperatures compared to slurries with high-quality coal dust. However, the established differences considering the availability and low cost of filter cakes illustrate the prospects of waste derived fuel combustion. The combustion heat of the investigated slurries based on coal and filter cake with addition of petroleum products differs by no more than 5–30%. The average difference between the duration of ignition for fuel droplets based on dust and filter cake of coking and low-caking coals is about 20%. At that the addition of waste turbine oil (10% wt.) into the filter cake reduces the duration of ignition by 12–25% and the ignition temperature – by 10–15 °C without a significant increase in anthropogenic gas emissions. The difference between the minimum ignition temperatures of coal and waste coal based slurries was from 10 °C to 80 °C. On environmental and economic indicators, coal waste is more attractive than coal.     

油页岩干馏残渣和生物质混烧污染物释放特性研究

基于自行搭建的流化床试验台,对桦甸油页岩干馏残渣和生物质混合燃料进行了不同掺混比例、不同床温、不同粒径下的燃烧试验,得到了混合物燃烧后污染物气体释放的体积分数,并分析了其产生机理.结果表明:各燃料中SO2的释放体积分数与其中的含硫量成正相关性;NOx气体的产生机理复杂,其主要取决于氮元素的转化率;油页岩干馏残渣和燃料灰烬均对SO2和NOx具有吸附作用;混合燃料颗粒粒径过小会阻碍反应的继续进行,导致燃烧不彻底.     

桦甸油页岩燃烧性能的热分析研究

利用热重分析仪在非等温条件下对桦甸油页岩进行了燃烧试验。考察了粒径、升温速率、样品种类等因素对油页岩燃烧特性的影响。采用积分法（C-R法）获得了油页岩的燃烧动力学参数。结果表明，油页岩的燃烧性能随着其挥发分含量的增大而变好，且在燃烧过程中油页岩的表现活化能变化很大，对于不同的燃烧温度范围可用不同的反应级数来描述，在燃烧前期反应级数为1级，而燃烧后期反应级数为3．5级。     

AN OPTICAL SYSTEM FOR THE QUANTITATIVE STUDY OF PARTICULATE CONTAMINATION ON SOLAR COLLECTOR SURFACES

We describe a computerized microscope system that has been developed for studying the physics of dust particles which adhere to various kinds of surfaces such as those of solar collectors. The device enables investigators: (1) to obtain the particle size distribution of dust on a surface; (2) to calculate the fraction of surface area covered by dust; (3) to calculate the reduction of optical efficiency (of the solar collector under study) as a function of particle size; (4) to investigate the effect of various kinds of applied force field on the adhesion of dust particles to the surface. Some examples are given for the use of such a measuring system for the study of photovoltaic and solar-thermal collector surfaces.     

Development of a new model of olives de-stoner machine: Evaluation of electric consumption and kernel characterization

In this scientific paper, the quantitative and qualitative performances of three different de-stoner machines involved in an industrial olive oil plant were evaluated. The bioenergy production potential for olive stone in Italy was also estimated. The results confirmed that the best performance was obtained using the innovative partial de-stoner machine called “Moliden” because it does not lead to losses in oil extraction efficiency (as opposed to the total de-stoner machine) and it also extracts an amount of olive stone (approximately 65% of the total stone contained in the olives) that is greater than that obtained using the husk de-stoner machine (58%). In addition, the olive stone obtained by using a partial de-stoner machine contains lower oil, fine particle sizes and nitrogen compared to the olive stone obtained by using a husk de-stoner machine. This leads to advantages regarding combustion efficiency and the environment. Considering the olive production in Italy and in the Mediterranean basin, olive stone might be an attractive renewable source for energy production.