大庆某低渗轻质油藏注空气低温氧化反应动力学研究

轻质油藏注空气提高采收率的机理之一是在油藏中发生低温氧化反应,低温氧化反应进行的程度将对油藏注空气开发的可行性产生决定性的影响。通过在RUSKA2370-601PVT筒中进行的大庆某低渗油田原油与空气恒温恒压氧化反应实验数据,获得轻质油藏注空气低温氧化反应动力学参数为:原油氧化反应为零级反应;21 MPa,87℃时氧化反应的速度常数KO2为1.2255×10-4mol/(mL.h),21 MPa,127℃时氧化反应的速度常数KO2为7.0101×10-4mol/(mL.h),原油样品的阿仑尼乌斯活化能Ea为52.1 kJ/mol。     

火烧油层实验中空气流动率和压力的影响

在火烧油层实验中,我们用到的燃烧管长度是1 m,内径是0.0381 m。这次研究的目的是来研究压力和空气流动率对温度,油藏,前缘速率,氧气利用率和产气量的影响。我们可以发现,随着压力的增高。(1)当压力小于6 384.5 kPa时,燃烧前缘平均温度和速度都增加。(2)采收率降低(3)氧气利用率减小,但是,当压力高于6 384.5 kPa,燃烧前缘平均温度和速度都减小。另一方面,当空气流动率从5.73×10-5m3/s增加到7.6×10-5m3/s时候,所有参数都增加。     

沈161区块注空气开发可行性实验研究

针对沈161区块储层物性差,非均质性强等特点,在长期高压注水条件下未能取得很好的驱油效果,而注空气成本便宜,且低渗油藏空气驱有很多成功案例。采用室内物理模拟实验研究空气驱可行性。通过水、空气驱油实验,气驱采收率为65.56%,比水驱高13.5个百分点;细长管空气驱低温氧化实验研究和燃烧管高温氧化实验研究,确定空气驱安全时间是注入1.2 PV,实现高温氧化的点火温度应该在400℃以上,且越高越好。     

In-situ combustion laboratory studies of Turkish heavy oil reservoirs

The purpose of this research was to perform dry and wet forward combustion experiments for Turkish heavy oil reservoirs (Raman, Adıyaman and Çamurlu and Batı Kozluca) under different experimental conditions. In the experiments, a vertical tube was packed with crushed limestone and saturated with crude oil and water. It was observed that peak temperatures were higher when stabilized combustion was achieved and decreased as the combustion front approached the outlet end of the tube. In wet combustion experiments, the rate of combustion reaction and therefore rate of heat generation were reduced with the resultant drop in peak temperatures. In dry and wet combustion experiments, excess carbon-dioxide productions were observed due to the decomposition of carbonate minerals. Atomic H/C ratio of the fuel consumed decreased as the average peak temperature increased. Fuel consumption rate was higher for dry combustion experiments as the °API gravity of the crude oils increased. A decrease is also observed in fuel consumption rate after the water–air ratio value is reached to optimum value. For high water–air ratio in wet combustion experiments, a general decrease was observed as the °API gravity of the crude oils increased.     

Coal combustion characteristics in a fluidized bed combustor with a draft tube

The effects of gas velocity to draft tube (3–6 U_m), bed temperature (800–900°C) and excess air ratio (0–30%) on the total entrainment rate, overall combustion efficiency and heat transfer coefficient have been determined in an internally circulating fluidized bed combustor with a draft tube. The total entrainment rate increases with an increase in gas velocity to draft tube, but decreases with increasing bed temperature and excess air ratio. The overall combustion efficiency increases with increasing excess air ratio, but decreases with increasing gas velocity to draft tube. The overall combustion efficiency obtained in internally circulating fluidized beds was found to be somewhat higher than that in a bubbling fluidized bed combustor.     

Enthalpies of pyrolysis and oxidation of Athabasca oil sands

Thermal degradation of Athabasca oil sands, bitumen, and its fractions have been investigated in N₂and in air, at 25–600 °C and at pressures up to 6.9 MPa, using thermogravimetry (TG) and high pressure differential scanning calorimetry (PDSC). These conditions are likely to occur during in-situ recovery of bitumen by underground combustion processes. Two regions of weight loss are detected using both gases. The endothermic low temperature volatilization reactions (150–400 °C) absorbed +26 mJ mg^?1 for oil sand to +2319 mJ mg^?1 for medium oil. The heats of reaction for high-temperature cracking and volatilization reactions (400–550 °C) were similar. The heats of reaction for the low-temperature oxidation reactions (150–375 °C) were ?405 mJ mg^?1 for oil sand to ?30200mJ mg^?1 for medium oil. Values for the high-temperature oxidation reactions (400–550 °C) were slightly higher. Increasing the pressure of nitrogen and air caused an increase in the endothermicity and exothermicity of the respective reactions.     

Aging of polypropylene using high oxygen pressure: Influence of sample thickness and stabilization

Thin films (0.05–0.08 mm thick) of stabilized and unstabilized polypropylene were aged under 4.24 MPa (614 psi) of oxygen at 90°C. The oxidation of these films was monitored using transmission infrared spectroscopy. Previously it was shown that embrittlement for the thin unstabilized polypropylene films occurred 3.6 times faster in 4.24 MPa of oxygen than in air at atmospheric pressure. For thick stabilized polypropylene (3.18 mm thick), the oxidative induction time at 120°C and 4.24 MPa of oxygen was drastically reduced compared with conventional air aging at this temperature. Specifically, sample embrittlement occured in 1 week during the high oxygen pressure aging in stark contrast to 70 weeks for conventional air aging. Consequently, due to the shortening of time to age samples at high oxygen pressures, aging can be conducted at this lower temperature (nearer the service temperature) rather than at this commonly used aging temperature of 150°C.     

Regeneration of spent activated carbon by wet air oxidation

The regeneration of activated carbon was studied using the wet air oxidation process in the temperature range of 150–240°C and oxygen partial pressure range of 0.2 to 1.0 MPa. Phenol was used as substrate. The overall mechanism of regeneration has been analysed and the different steps taking place during the regeneration process were individually investigated. Kinetics of oxidation of phenol and oxygen mass transfer coefficients have been estimated in the ranges of temperature and pressure studied. Oxidative degeneration characteristics of activated carbon were also studied. The conditions of temperature and pressure have been found at which the extent of regeneration is favourable.     

Thermogravimetric and differential thermal analysis of cellulose,hemicellulose, and lignin

The thermal degradation of samples of cellulose, hemicellulose, and lignin have been investigated using the techniques of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) between room temperature and 600°C. The results calculated from static and dynamic TGA indicated that the activation energy E for thermal degradation for different cellulosic, hemicellulose, and lignin samples is in the range 36–60, 15–26, and 13–19 kcal/mole, respectively. DTA of all the wood components studied showed an endothermic tendency around 100°C in an atmosphere of flowing nitrogen and stationary air. However, in the presence of flowing oxygen this endothermic effect was absent. In the active pyrolysis temperature range in flowing nitrogen and stationary air atmospheres, thermal degradation of Avicel cellulose occurred via a sharp endothermic and a sharp exothermic process, the endothermic nadir and exothermic peak being at 320° and 360°C, respectively. In the presence of oxygen, combustion of Avicel cellulose occurred via two sharp exothermic processes. DTA studies of different cellulose samples in the presence of air showed that the shape of the curve depends on the sources from which the samples were prepared as well as on the presence of noncellulosic impurities. Potassium xylan recorded a sharp exothermic peak at 290°C in a nitrogen atmosphere, and in a stationary air atmosphere it yielded an additional peak at 410°C, while in the presence of oxygen the curve showed two sharp exothermic peaks. DTA traces of periodate lignin in flowing nitrogen and air were the same and showed two exothermic peaks at 320° and 410°C, while in the presence of oxygen there were two exothermic peaks in the temperature range 200°–500°C.     

Pyrolysis with partial combustion of oil shale fines in a spouted bed

Pyrolysis with partial combustion of oil shale fines from the Irati Formation in Brazil has been investigated in a 30 cm diameter spouted bed reactor. Experiments were carried out at atmospheric pressure and temperatures between 450 and 600°C. The oi] shale particle size was less than 6.35 mm. Spouting gas temperatures ranged from 20 to 565°C. Three inlet gas pipe diameters and two spouted bed heights were studied. Operation of the process was found to be stable over a wide range of test conditions. Results are presented for oil and gas quality, efficiency of retorting and overall performance of the plant.     

Low NOx heavy fuel oil combustion with high temperature air

For an industrial-scale test furnace, the development and investigation of a heavy-oil-fired burner in a highly preheated air combustion system are discussed. The 1200 °C highly preheated combustion air was achieved by burners equipped with regenerators in high-cycle reciprocal firing. It was observed that the high-cycle reciprocal firing enhanced convective heat transfer to the furnace wall. Reduction of nitric oxide emissions was achieved by fuel directly injected into furnace (F2 mode) and mixed with combustion products. In previous studies of natural gas combustion in reciprocal firing, two injectors located at the burner quarl have been utilized to achieve low nitric oxide combustion. In this study, reduction of nitric oxide was investigated using single or paired atomizers located in the upper and lower position of burner quarl. It was found that buoyant forces were important for the mixing of fuel oil with high temperature air and for the resultant nitric oxide emission. Nitric oxide emission was found to be low with the paired atomizers in the F2 firing mode. Nitric oxide emission can be further reduced by use of a single atomizer rather than using paired atomizers.     

Surface energy of liquid copper and single-crystal sapphire and the wetting behavior of copper on sapphire

The wetting behavior of liquid copper on sapphire is affected by the crystallographic orientation of the sapphire surface, the oxygen partial pressure, and the temperature. The influences of each of these conditions have been studied by the sessile drop technique over the oxygen partial pressure range 10^-2-10^-20 atm at temperatures of 1100 and 1250°C. The effect of oxygen partial pressure on the liquid copper surface energy follows the Gibbs-Langmuir law. The contact angle varies with the crystallographic orientation of the sapphire surface. This variation is more significant at higher oxygen partial pressures, but is eliminated at higher temperatures. The liquid copper surface energy was determined to be γ_lv = 1.757-3.3 x 10^-4T(°C) J/m². The solid surface energy of sapphire was estimated as γ_sv = 1.961-4.7x 10^-4T(°C) J/m², which applies only to the temperature range 927-2077°C.     

Effect of organic substances in clay rocks on formation of a black core in ceramics

When clay rocks are heated, decomposition of organic substances is accompanied by liberation of H₂, CO, and CO₂, which creates the reducing character of the gas medium. Combustion of residual carbon takes place in the 250–500°C temperature region and is extremal in character due to diffusion of oxygen into the internal layers of the heat-treated material. To exclude a black core, holding in the 700–800°C region is recommended for completing combustion of oxygen and forming hollow articles with the minimum acceptable thickness of the external and internal walls.     

Influence of Polydimethylsiloxane on the Oxygen Concentration of Oils at Various Temperatures

The effect of temperature on the oil oxygen concentration, tested in both soybean and olive oils with no added polydimethylsiloxane (PDMS), showed that the oxygen concentration increased with temperature to approximately 100 °C. Above 100 °C, the oxygen concentration abruptly decreased. This change was attributed to the balance between the rates of oxygen uptake and consumption by oil oxidation, which favored oxygen consumption over uptake at temperatures above 100 °C. The addition of 100 ppb PDMS to soybean oil, enough to form a continuous layer over the surface of the oil, reduced the oxygen concentration when compared to a soybean oil control containing no added PDMS at temperatures ranging from 93 to 180 °C; thus suggesting an oxygen barrier effect of PDMS. The accumulation of PDMS at the air–oil interface in soybean oil held at 180 °C was determined by comparing the oil’s internal temperature and the apparent surface temperature. A decrease in the apparent surface temperature while the oil was held at a constant internal temperature was attributed to a change in the emissivity of the surface as a consequence of the accumulation of PDMS in the air–oil interface. The presence of PDMS at the air–oil interface was confirmed for 100 ppm of PDMS, a concentration greater than the concentration necessary to form a monolayer of PDMS on the oil surface.     

Oxidation behavior of ZrB2-SiC-ZrC at 1700 °C

The oxidation behaviors of four compositions of ZrB₂-SiC-ZrC and one composition of ZrB₂-SiC were studied at 1700 °C in air and under low oxygen partial pressure. Volatility diagrams for ZrB₂-SiC-ZrC and ZrB₂-SiC were used to thermodynamically elucidate the oxidation mechanisms. SiO₂ and ZrO₂ layers formed on the surfaces of ZrB₂-SiC-ZrC and ZrB₂-SiC oxidized at 1700 °C. A SiC-depleted layer only formed on the surface of the ZrB₂-SiC oxidized under low oxygen partial pressure. The oxide layer thickened with increasing ZrC volume content during oxidation in air and under low oxygen partial pressure. The ZrB₂-SiC-ZrC oxide surface exploded in air when the ZrC volume content was more than 50%. Under low oxygen partial pressure, the oxide surfaces of all the ZrB₂-SiC-ZrC specimens bubbled.     

Combustion behaviour of bituminous and anthracite coal char between 425 and 900 °C

The combustion behaviour of bituminous and anthracite coal char has been studied for temperatures ranging from 425 to 900 °C. The combustion reaction was carried out in a thermogravimetric analyser at 1 atm. A wide range of oxygen partial pressures, from 5×10^?4 to 10^?1 MPa was used. For bituminous char, below 600 °C the intrinsic reaction order and activation energy are 0.75 and 29.0 kcal gmol^?1, respectively, while above 650 °C, the intrinsic reaction order and activation energy are 0.3 and 45.2 kcal gmol^?1. For anthracite char, below 600 °C the intrinsic reaction order and activation energy are 0.9 and 32.8 kcal gmol^?1, while above 650 °C, the intrinsic reaction order and activation energy are 0.3 and 43.6 kcal gmol^?1. The changes in the reaction order and activation energy in the temperature ranges above and below 600 °C imply that the dominant reaction mechanism is different for these two temperature ranges.     

Use of oxygen for burning fuel in rotary kilns

Conclusions Preheating mazut oil up to 100°C and using hot producer gas with a temperature of 300°C, and also preheating air to 250°C may provide an increase in the furnace temperature of approximately 10%. Enriching the air used for combustion with oxygen is an effective method of boosting the combustion temperature in rotary furnaces.With an increase in the oxygen content in the oxidizing agent of from 21 to 30% in practice the combustion temperature of natural gas, using cold air, rises from 1570 to 2000°C. This temperature will be adequate for the thorough sintering of raw pure magnesite.Translated from Ogneupory, No. 8, pp. 9–14, August, 1968.     

Oxidative Rancidity in Refined Sunflower Oil with Respect to Storage Variation

Refined sunflower oil was stored in brown and colorless glass bottles at ambient temperature (18–32°C) and 37°C to assess the effect of light, heat and air on the stability fo the oil and to record the progress of oxidative rancidity especially the secondary stages with respect to storage variation and time. Oil sample stored in brown color bottle was found to be superior (FFA 0.15 to 0.53; PV 0.5 to 80; HV 3 to 12; oxirane oxygen 0.2 to 2.3) over oil stored in colorless bottle (FFA 0.15 to 0.60; PV 0.5 to 91; HV 3 to 8; oxirane oxygen 0.1 to 2.8) at ambient temperature. Samples stored at 37°C deteriorated very fast. Silver nitrate test, oxidised fatty acid formation, urea adduct formation, picric acid-TLC test, Kreis test, DNP-TLC test, DNP-precipitation test have been devised to detect and follow oxidative rancidity. These tests worked well even at the lower levels of oxycompounds. No conjugation was detected in any of the oil.     

Coal char combustion under a CO2-rich atmosphere: Implications for pulverized coal injection in a blast furnace

Pulverized coal injection (PCI) is employed in blast furnace tuyeres attempting to maximize the injection rate without increasing the amount of unburned char inside the stack of the blast furnace. When coal is injected with air through the injection lance, the resolidified char will burn in an atmosphere with a progressively lower oxygen content and higher CO₂ concentration. In this study an experimental approach was followed to separate the combustion process into two distinct devolatilization and combustion steps. Initially coal was injected into a drop tube furnace (DTF) operating at 1300 °C in an atmosphere with a low oxygen concentration to ensure the combustion of volatiles and prevent the formation of soot. Then the char was refired into the DTF at the same temperature under two different atmospheres O₂/N₂ (typical combustion) and O₂/CO₂ (oxy-combustion) with the same oxygen concentration. Coal injection was also performed under a higher oxygen concentration in atmospheres typical for both combustion and oxy-combustion. The fuels tested comprised a petroleum coke and coals currently used for PCI injection ranging from high volatile to low volatile bituminous rank. Thermogravimetric analyses and microscopy techniques were used to establish the reactivity and appearance of the chars.     

The rapid determination of nitrogen in Primary and Secondary Explosives using the Merz Method

The rapid determination of nitrogen in explosives is basically possible using the Heraeus automatic Mikrorapid N as developed by Merz. The combustion of the substance takes place in pure oxygen and the nitrogen is determined volumetrically. However, when sodium and lead azides are analyzed in this way the residues of sodium and lead strongly attack the quartz of the combustion tube. In order to achieve the longest possible service life of the combustion tubes a joint investigation with BASF AG was undertaken to test other tube materials (e. g. steels, nickel, Alsint, Phythagoras) in addition to quartz. Pythagoras proved to be the most suitable material for the combustion of all explosives at 950° C in the same tube. For the determination of sodium azide a quartz finger (according to Merz) can be inserted in the tube which, at 500° C, collects the sodium residues.