Water processing

Utilities (fuel, steam, electricity, cooling water, process water, compressed air, inert gases, etc.)... 

Total 1991 world production of sulfur in all forms was 55.6 x 10 t. The largest proportion of this production (41.7%) was obtained by removal of sulfur compounds from petroleum and natural gas (see Sulfurremoval and recovery). Deep mining of elemental sulfur deposits by the Frasch hot water process accounted for 16.9% of world production mining of elemental deposits by other methods accounted for 5.0%. Sulfur was also produced by roasting iron pyrites (17.6%) and as a by-product of the smelting of nonferrous ores (14.0%). The remaining 4.8% was produced from unspecified sources. 

Metal—Water Processes. The steam-iron process, one of the oldest methods to produce hydrogen, iavolves the reaction of steam and spongy iron at 870°C. Hydrogen and iron oxide are formed. These then react further with water gas to recover iron. Water gas is produced by reaction of coal with steam and air. 

Newer technology involves aqueous-processible photopolymer plates. Many plate-makers and printers are eager to switch to water processing in order to eliminate volatile organic solvents. The chemistry and process of use are similar to that of the solvent-processible plate except that in the aqueous plate, the elastomer has pendent carboxyl, hydroxyl, or other water-soluble groups to allow aqueous processing. 

Checking Against Optimum Design. This attempts to answer the question whether a balance needs to be as it is. The first thing to compare against is the best current practice. Information is available ia the Hterature (13) for large-volume chemicals such as NH, CH OH, urea, and ethylene. The second step is to look for obvious violations of good practice on iadividual pieces of equipment. Examples of violations are stack temperatures > 150° C process streams > 120° C, cooled by air or water process streams > 65° C, heated by steam t/ urbine 65% reflux ratio > 1.15 times minimum and excess air > 10% on clean fuels. 

Hot-Water Process. The hot-water process is the only successflil commercial process to be appHed to bitumen recovery from mined tar sands in North America as of 1997 (2). The process utilizes linear and nonlinear variations of bitumen density and water density, respectively, with temperature so that the bitumen that is heavier than water at room temperature becomes lighter than water at 80°C. Surface-active materials in tar sand also contribute to the process (2). The essentials of the hot-water process involve conditioning, separation, and scavenging (Fig. 9). 

Froth from the hot-water process may be mixed with a hydrocarbon diluent, eg, coker naphtha, and centrifuged. The Suncor process employs a two-stage centrifuging operation, and each stage consists of multiple centrifuges of conventional design installed in parallel. The bitumen product contains 1—2 wt % mineral (dry bitumen basis) and 5—15 wt % water (wet diluted basis). Syncmde also utilizes a centrifuge system with naphtha diluent. 

An attempt has been made to develop the hot-water process for the Utah sands (Fig. 10) (20). With od-wet Utah sands, this process differs significantly from that used for the water-wet Canadian sands, necessitating disengagement by hot-water digestion in a high shear force field under appropriate conditions of pulp density and alkalinity. The dispersed bitumen droplets can also be recovered by aeration and froth flotation (21). 

One problem resulting from the hot-water process is disposal and control of the tailings. Each ton of oil sand in place has a volume of ca 0.45 m, which generates ca 0.6 m of tailings and gives a substantial volume gain. If the mine produces 200,000 t/d of oil sand, volume expansion represents a considerable soflds disposal problem. 

H.-G. Heitman, Saline Water Processing, VCH PubHcations Inc., Weioheim, Germany, and New York, 1990. 

Fig. 1. Simplified flow diagrams for H2S/H2O heavy water processes, (a) Dual-temperature system where the pressure is 1.90 MPa (b) siagle-temperature...

It is shown that metrological characteristics of the suggested methods are commensurable. Dissolved gas is pushed away by front of crystallization, takes the air and does not influence on the obtained results during the analysis of the water. Process is carried out at the lower temperature (-15°C), expelling chemical transformations of ingredients. The procedure was tested on different samples of natural and drinking water of the Kharkov region. 

Relatively large volumes of water are used by the petroleum refining industry. Four types of wastewater are produced surface water runoff, cooling water, process water, and sanitary wastewater. Surface water runoff is intermittent and... 

Economic distribution of services (water, process steam, power, and gas)... 

H, Frasch developed commercial recovery of S by superheated water process. 

Membrane processes are not yet used widely for industrial water processing, but will become more important in future. At present, they are generally more expensive than the older processes which they promise to replace, but costs are falling. Their main advantage lies in the fact that they add little or no chemicals to the aqueous environment but return to it only the material taken from the raw water. 

Brigham, R. J. andTozer,E. W., Temperatureas a Pitting Criterion , Corrosion, 29,33(1973) Bruce, S., Specialist Steels Combat Corrosion by Chloride-containing Cooling Water , Process Eng., 88 (1973) C.A., 80, 6176k... 

Traditionally, the mix of pretreatment equipment required to meet a specific FW volume and quality specification is provided as a permanent installation under a capital project, although today there is a growing global market in outsourced water services. Typically, vendors such as Ecolochem, Inc., a world leader in this type of service, provide trailer-mounted, mobile water-processing equipment that can be... 

To hinder the complex reaction induced by the very unstable peroxysulfonic acid in the so-called light-water process, excess sulfur dioxide in the presence of water is used to reduce the peracid as follows ... 

The continuous light-water process developed by Hoechst [4] comprises five steps sulfoxidation, extract treatment, neutralization, distillation, and final treatment. Typically, the sulfoxidation proceeds in a trough-like reactor (1 in Fig. 2) of 55-m3 volume. The reactor has 40 UV lamps which are energized between 18 and 28 kW. 

Kinunerer WJ (2004) Open water processes of the San Francisco Estuary from physical forcing to biological responses. San Francisco Estuary Watershed Sci 2(1) Article 1. http // repositories.cdlib.org/Jmie/sfews... 

This has been a very useful area of metrics exploration. In general terms, one can simply divide mass into key types, such as mass of solvent, water, process chemicals (i.e., not reactants) and reactants, and sum the amoimt of each. This may seem to be a bit simplistic, but simplicity does have the advantage of allowing one to discover what the key contributions to energy or waste are from a materials perspective, and this can in turn drive one to consider less impactful alternatives. 

This difference originates from the different heat capacities of the reaction mixtures. The large difference between the process heats could not be attributed to dilution of the aromatic compound in the nitric acid/water mixture. The difference increased by adding a larger amount of nitric acid.The heat of the solvent process, that was run in such a way that the heat flux was kept constant, only increased slightly due to the aromatic dilution by the acid added to the reaction mixture. In contrast, extra acid addition resulted in a significant rise of the thermal effect of the water process (to 209 kJ/kg), indicating that formation of a di-nitro compound proceeds. 

A DSC instrument was used to assess the possible consequences of a potential thermal runaway using post-nitration mixtures for evaluations (see Fig. 5.4-65). For the solvent process two minor peaks between 150 and 220 °C appeared, which correspond to thermal effects of -15 kJ/kg and -9 kJ/kg. In contrast, a large thermal effect (-730 kJ/kg) was observed for the reaction mixture from the water process, located between 90 and 160 °C. Based on these data the risk of a thermal runaway for both processes was assessed. 

Fig. 5.4-66 outlines the probability and consequences of a thermal runaway in case of a plant incident. For the solvent process, failure results in a temperature rise from 27 °C to 119 °C. This is far from the onset temperature of secondary processes, which only start at 150 °C or higher. Consequently, the solvent process can be considered safe. A failure of the water process can cause a temperature rise from 50 to 95 C, i.e. higher than the onset temperature (90 °C) of the secondary decomposition of the di-nitro compound. The decomposition would start before the reaction mixture started boiling. Hence, the water process cannot be considered inherently safe. 

Figure 5.4-66. Comparison of the solvent and the water process (adapted from Hoppe and Grob, 1990).

Mains water (process water) Natural gas Electricity Fuel oil... 

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