In-situ remediation technology has been studied for the oil-contaminated soil caused by the Gulf War in Kuwait. The developed treatment process combines solvent washing and water washing of oil-contaminated soil. After laboratory experiments, bench scale experiments, and fabrication and operation of the pilot scale plant to treat three ton per day of oil-contaminated soil, field scale experiment (thirty tons per day) was conducted. Through operation of the field scale plant, a total of 2, 500tons of oil-contaminated soil was treated. Oil and salt contamination levels in the treated soil were both reduced below 2.5wt%. Salt content in the recovered oil from the soil washing process could be reduced to less than 3, 500ppm, and API was increased to 30°, when additional heat, solvent, water and emulsion breaker were used in an ancillary process.
Bitumen in oil sands is extra heavy crude oil. Bitumen's API gravity is between 8 and 12 and its viscosity is from 100, 000mPa·s to 8, 000, 000mPa·s. Bitumen has no mobility at the original reservoir temperature (10°C). In order to reduce its viscosity, thermal method should be applied to recover the bitumen. Bitumen-in-place in Alberta of Canada is estimated to be about 1 .7 trillion barrel and bitumen is expected to be an important energy source in the near future. Steam Assisted Gravity Drainage (SAGD) method is new promising technology for bitumen recovery. Twin horizontal wells are drilled to apply the SAGD method.
In this review, it is described that new information can be obtained by applying new ESR methods to the radicals contained in coals. High frequency ESR measurements enable us to observe the highly resolved ESR signals. Thus, the mechanism of linewidth broadening of the ESR signals for coal radicals can be discussed in terms of the spin exchange, the hyperfine interaction and the anisotropy of g-value. By pulsed ESR measurements, various kinds of spectra such as nutation spectra and HYSCORE (hyperfine sublevel correlation spectroscopy) spectra are obtained. The nutation method confirms the spin multiplicity of coal radicals. The 1H-and 13C-hyperfine signals are separately observed in HYSCORE spectra. In comparison with the model compounds, main coal radicals are attributed to the radicals with highly symmetrically condensed aromatic hydrocarbons.
Pressurized Fluidized Bed Combustion (PFBC) combined cycle system which has high plant efficiency due to installed steam turbine and gas turbine, and high performance for environment, becomes a subject of world attention. Two configurations of cyclones and ceramic tube filter (CTF) were examined for gas purification in 71MWe PFBC plant at Wakamatsu, Electric Power Development CO., LTD. where whole cyclones removed all coarse ashes not sent to CTF in one configuration and the cyclones were partially bypassed in order to send a part of the coarse ash to CTF in another configuration. The first configuration suffered a larger pressure drop across the CTF, which reached 40 to 45KPa (4, 000mmAq to 4, 500mmAq), and several times of ash plugging, leading to filter breakage during a couple of weeks operation . Increased pressure drop required frequent back pulse cleaning to remove accumulated ash on CTF . Partial bypass of the cyclones reduced very much the pressure drop even if more ash was introduced to CTF, and hence frequency of back pulse cleaning was decreased by the configuration with bypass. No filter breakage was experienced at all, since the cyclone bypass system has been introduced. Thus around 800 hours continuos operation was achieved by the configuration, increasing the efficiency of power generation by 0.5% due to saved auxiliary power for back pulse cleaninig. The roles of coarse ash sent to CTF with cyclone bypassed are discussed in the pressure drop due to the accumulated ash on the CTF.
The method of low NOx Combustion by Mixing Water was developed in order to reduce NOx emission and smoke in incinerators and oil-fired boilers with oil-pressure atomizing burners. This technique brought a simpler, smaller, more economical and more practical system than known emulsion-fuel combustion method. The principle of this technique is based on making combustion immediately after mixing liquid fuel with water at the tip of the nozzle by utilizing the swirling power of high pressure atomization. The application of this technique for oil-fired boilers is expected to be popularized in near future, as a way of environmental protection in big cities.