Conventional production techniques

Since the late 1960s, the ultimate amount of cmde petroleum in the world that is producible through conventional production techniques has been estimated to be about 350 x 10 (2.2 x 10 bbl) (9,11—13). By the end of 1991, cumulative world production was... 

Tar sand, also variously called oil sand (in Canada) or bituminous sand, is the term commonly used to describe a sandstone reservoir that is impregnated with a heavy, viscous black extra heavy cmde oil, referred to as bitumen (or, incorrectly, as native asphalt). Tar sand is a mixture of sand, water, and bitumen, but many of the tar sand deposits in the United States lack the water layer that is beHeved to cover the Athabasca sand in Alberta, Canada, thereby faciHtating the hot-water recovery process from the latter deposit. The heavy asphaltic organic material has a high viscosity under reservoir conditions and caimot be retrieved through a weU by conventional production techniques. 

Tar sands is an expression commonly used in the petroleum industry to describe sandstone reservoirs impregnated with a very heavy viscous crude oil which cannot be produced through a well by conventional production techniques. Two other terms, bituminous sands and oil sands, are gaining favor. The heavy viscous petroleum substances impregnating the tar sands are called asphaltic oils. See also Tar Sands. 

Bituminous sand a formation in which the bituminous material (see Bitumen) is found as a filling in veins and fissures in fractured rocks or impregnating relatively shallow sand, sandstone, and limestone strata a sandstone reservoir that is impregnated with a heavy, viscous black petroleum-like material that cannot be retrieved through a well by conventional production techniques. 

Besides some satisfactory results, the research has shown many difficulties related either to the costs or to the prices faced by organic farms. The costs are mainly due to the wide gap between organic and conventional production techniques. Prices are typical of the building up of a new niche market. For now, these difficulties seem to prevent a rapid expansion of domestic supply of organic meat in Veneto, although specific research programs could overcome some of them. 

Controllability is an important aspect of a delivery system. Preferably, a system should be controlled in such a way that the release of drugs is possible within a certain range, so that with any given system different release patterns should be feasible to respond to an individual patient s specific need. Material costs are also important. Commercially, there is no use in developing a drug delivery system in which the benefits are canceled out by the costs. To reduce costs, conventional production techniques are often beneficial in comparison to specially developed new techniques. 

Nonferrous Metal Production. Nonferrous metal production, which includes the leaching of copper and uranium ores with sulfuric acid, accounts for about 6% of U.S. sulfur consumption and probably about the same in other developed countries. In the case of copper, sulfuric acid is used for the extraction of the metal from deposits, mine dumps, and wastes, in which the copper contents are too low to justify concentration by conventional flotation techniques or the recovery of copper from ores containing copper carbonate and siUcate minerals that caimot be readily treated by flotation (qv) processes. The sulfuric acid required for copper leaching is usually the by-product acid produced by copper smelters (see Metallurgy, extractive Minerals RECOVERY AND PROCESSING). 

The solid-liquid separation of shinies containing particles below 10 pm is difficult by conventional filtration techniques. A conventional approach would be to use a slurry thickener in which the formation of a filter cake is restricted and the product is discharged continuously as concentrated slurry. Such filters use filter cloths as the filtration medium and are limited to concentrating particles above 5 xm in size. Dead end membrane microfiltration, in which the particle-containing fluid is pumped directly through a polymeric membrane, is used for the industrial clarification and sterilisation of liquids. Such process allows the removal of particles down to 0.1 xm or less, but is only suitable for feeds containing very low concentrations of particles as otherwise the membrane becomes too rapidly clogged.2,4,8... 

Certain transition metal salts can be used as radical traps (Scheme 3.89, Scheme 3.90).486 These include various cupric (e.g. Cu(OAc)2, CuCl , Cu(SCN)i),l8 1<,8 J< 3 432 487 ferric (e.g. FeCli),316 488 and titanotis salts (eg. TiCL,).379 These traps react with radicals by ligand- or electron-transfer to give products which can be determined by conventional analytical techniques. 

Metallic electrodes may dissolve as a result of electrolysis and may introduce corrosion products into the solid mass. However, if the electrodes are made of carbon or graphite, no residue will be introduced in the treated soil mass as a result of the process. The energy expenditure for Pb removal has been estimated to in the range 30 to 60 kWh/m1 2 3 4 of soil. The EO method also provides an advantage over conventional pumping techniques for in situ treatment of contaminated finegrained soils. 

The problem, from the point of view of the investigation of the mechanism, is that since the first electron transfer step is rate limiting, conventional kinetic techniques for studying the reaction are useless as a means of elucidating the overall mechanism and conventional spectroscopic techniques have also proved to be of little help. Gressin and colleagues (1979) were therefore driven to the careful study of the nature of the products as a function of reaction conditions. This work is seminal in the study of the direct reduction of C02 since the authors were able to produce a general scheme for the reaction of CO 2 that is now widely accepted. 

An alternative method to that of using a spreading machine or a calender for the initial preparation of fabrics for application of rubber (for composite product assembly) can be by the use of dip coaters. Application of rubber compound by this method ensures a better penetration of the fabric interstices than can be achieved by conventional frictioning techniques using calenders. More delicate fabrics which would not be strong enough for calender application can also be treated with rubber by this technique. 

The production of tight gas is technically very demanding. The major differences from conventional production arise because of the poor permeability of tight reservoirs, where the natural gas cannot flow as quickly to the well or in sufficient volumes to be economic, and where production rates are usually quite low. The principal prerequisite for economically producing tight gas is, therefore, to improve reservoir permeability, e.g., by artificial stimulation techniques, such as hydraulic fracturing (i.e., the generation of artificial fracture systems). 

The solids-liquid separation of slurries containing particles below 10 xm is difficult by conventional filtration techniques. A conventional approach would be to use a slurry thickener in which the formation of a filter cake is restricted and the product is discharged continuously as a concentrated slurry. Such filters use filter cloths as the filtration medium... 

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