Recovery efficiency design

Raw material usages per ton of carbon disulfide are approximately 310 m of methane, or equivalent volume of other hydrocarbon gas, and 0.86—0.92 ton of sulfur (87,88), which includes typical Claus sulfur recovery efficiency. Fuel usage, as natural gas, is about 180 m /ton carbon disulfide excluding the fuel gas assist for the incinerator or flare. The process is a net generator of steam the amount depends on process design considerations. 

Gas-Fired water heaters are also made more efficient by a variety of designs that increase the recov-ei y efficiency. These can be better flue baffles multiple, smaller-diameter flues submerged combustion chambers and improved combustion chamber geometry. All of these methods increase the heat transfer from the flame and flue gases to the water in the tank. Because natural draft systems rely on the buoyancy of combustion products, there is a limit to the recovery efficiency. If too much heat is removed from the flue gases, the water heater won t vent properly. Another problem, if the flue gases are too cool, is that the water vapor in the combustion products will condense in the venting system. This will lead to corrosion in the chimney and possible safety problems. 

For special applications the design of a mist eliminator unit may actually be an assembly in one casing of wire mesh and fiber packs/pads or in combination with Chevron style mist elements (see Figure 4-17A and 17B and — 17C.) This can result in greater recovery efficiencies for small particles and for higher flow rates through the combined unit. Refer to the manufacturers for application of these designs. 

Spacing of the plates and their angles is a part of the design using the manufacturers data. Muldple pass designs can result in higher recovery efficiencies. The units can be designed/installed for vertical or horizontal flow. 

Designing products so that disposal of end of life is easy and energy efficient. Designing products so that the embodied energy can be recovered at end of life. For example, producing plastics that can be burned for energy recovery without producing... 

Syncrude s Sulphur Recovery Units are two parallel trains of the conventional Claus plant consisting of thermal conversion and three catalytic reactors in series. Air is supplied to the furnace to oxidize sufficient H2S to SO2 such that an H2S S02 ratio of 2.1 1 is effected (1). The sulphur recovery efficiency is designed for approximately 95% (2) however, experience to date, at near design capacity, has indicated 98% H2S conversions and 97% sulphur recoveries (1). 

The methods and apparatus used in this investigation must be improved in order to increase the recovery efficiency and to automate the process. Design modification of the cathode and anodes is one obvious approach to enhancing the recovery capability of the process. 

The dry-based capacity of the equipment is 1.78 kg s-1, while the recovery efficiency of the particles is 98-99%. It is reported that the conditions of fluid dynamics are very stable and that the equipment can be operated with a very high concentration of dense phase. It is clear that at least one of the researchers major intentions in the design of the dryer is to lengthen the residence time of the particles. 

The CEA decomposition loop operates at low pressures, near 5 bar. This is because the decomposition reaction is favoured at lower pressures. However, the GA flow sheet is conducted at 70 bar, near the expected operating pressure of the secondary helium loop. This is to minimise mechanical and thermal stress induced by a large pressure gradient between the helium and the chemical process at high temperatures. The GA design of the decomposition loop allows for more heat recovery, but does so with a more complex configuration. In practice, trade-offs between complexity and cost will be necessary to develop the most cost-efficient design. 

The pyrolysis furnace effluent is processed for heat and product recovery in an efficient, low-cost recovery section. The recovery section design can be optimized for specific applications and/or selected based on operating company preferences. Flow schemes based on demethanizer first, deethanizer first and depropanizer first configurations are available for particular applications. Shown above is the depropanizer first scheme, which is primarily applicable to liquid crackers. 

The cooled reactor effluent can be processed in a nearby, existing ethylene plant recovery section to minimize capital investment. Alternatively, the effluent can be processed in a partial recovery unit to recover recycle streams and concentrate olefin-rich streams for farther processing in a nearby ethylene plant. If desired, KBR can provide an efficient design for a dedicated unit to process the whole stream for recovery of a full range of products, including polymer-grade propylene and ethylene. 

Improved Flue-Gas Heat Recovery. The majority of the heat losses in cracking furnaces is contained in the flue gas which leaves the furnace. Today s cracking furnaces with integrated waste heat recovery are designed for thermal efficiencies between 90 and 93%, which correspond to flue-gas outlet temperatures of about 130° to 180°C. A further decrease of the flue-gas outlet temperature usually is not economic, as the heat-transfer surface of the upper bundles becomes too large because of the small mean logarithmic temperature difference. 

As 30 per cent of the particles are below 10 /xm the high-efficiency design will be required to give the specified recovery. 

The semicontinuous design allows a more efficient heat recovery than a batch system. Heat recovery is perfomed by means of indirect economizers (Figure 12). Steam produced in the bottom deodorized oil-cooling section is sent in a closed thermosiphon loop to the top bleached oil-heating section to heat the incoming oil. A single thermosiphon system has a recovery efficiency of 50%. With a double system, coupled with a low-pressure steam-production device, up to 75% of heat can be recovered. 

Potential hydrocarbon losses from the overpressuring of operating vessels are controlled first by staged computer alerts and/or manual alarms to provide for correction of the condition. If the overpressure exceeds a second set point, pressure relief valves vent the vessel contents to a flare release system. The flare system provides a means of controlled burning of hydrocarbon vapors at a nonhazardous point to avoid fire or explosion risks. Smoke problems from flares are avoided by more efficient designs that use multiple nozzles and low pressure operation to promote clean combustion [57]. Greenhouse gas concerns should more frequently stimulate an interest in energy recovery options from flared hydrocarbons. 

The design of a stirred tank fermenter for the production of an industrial enzyme at an annual rate of 800 5% mt/yr is illustrated below. Product recovery efficiency is 80% and the expected yield (product concentration) is 75kg/m. Maximum oxygen uptake demand is 185 mmol 02/L/hr. Operational parameters and media physical properties are listed as follows. 

Skimmers are mechanical devices designed to remove oil from the water surface. They vary greatly in size, application, and capacity, as well as in recovery efficiency. Skimmers are classified according to the area where they are used, for example, inshore, offshore, in shallow water, or in rivers, and by the viscosity of the oil they are intended to recover, that is heavy or light oil. 

In opt mazing any separation process it becomes necessary lo compute the product recovery efficiency of the operation as a fuuciion of design variables. For crystallization operations the ihsoretical maximum product recovery or yield from (he crystallizer is defiand by [ha following general relationship ... 

In addition to all of the problems that determine whether the injected mixture of C02 and surfactant solution can perform and survive as a foam in the reservoir rock, the operator of the oil field must design the procedures for injection and other operations in an advantageous way, so that profitability and oil recovery will be maximized. In this pairing of objectives, the oil field s leaseholders and owners are naturally more interested in the best return on their investment than, for instance, in the eventual total recovery. The latter objective, concerned with the overall recovery efficiency, should be the first consideration of the regulating authority. These operational problems entail new factors that transcend those encountered in the laboratory. From the point of view of the operator, the most important considerations are cost and availability of the additional supplies and materials needed, and whether the expected increase in oil production will be more than enough to pay for them. 

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