Operating conditions

Most processes are catalyzed where catalysts for the reaction are known. The strategy will be to choose the catalyst, if one is to be used, and the ideal characteristics and operating conditions needed for the reaction system. Decisions must be made in terms of reactor  [c.15]

Before we can proceed with the choice of reactor and operating conditions, some general classifications must be made regarding the types of reaction systems likely to be encountered. We can classify reaction systems into five broad types  [c.18]

Having discussed the choice of reactor type and operating conditions at length, let us try two examples.  [c.49]

Reactor conversion. In Chap. 2 an initial choice was made of reactor type, operating conditions, and conversion. Only in extreme cases would the reactor be operated close to complete conversion. The initial setting for the conversion varies according to whether there are single reactions or multiple reactions producing byproducts and whether reactions are reversible.  [c.95]

Reaction rates often may be improved by using more extreme operating conditions. More extreme conditions may reduce inventory appreciably. However, more extreme conditions bring their own problems, as we shall discuss later. A very small reactor operating at a high temperature and pressure may be inherently safer than one operating at less extreme conditions because it contains a much lower inventory. A large reactor operating close to atmospheric temperature and pressure may be safe for different reasons. Leaks are less likely, and if they do happen, the leak will be small because of the low pressure. Also, little vapor is produced from the leaking liquid because of the low temperature. A compromise solution employing moderate pressure and temperature and medium inventory may combine the worst features of the extremes. The compromise solution may be such that the inventory is large enough for a serious explosion or serious toxic release if a leak occurs, the pressure will ensure that the leak is large, and the high temperature results in the evaporation of a large proportion of the leaking liquid.  [c.263]

Low pressure. Low pressures are not in general as hazardous as the other extreme operating conditions. However, one particular hazard that does exist in low-pressure plants handling flammable materials is the possible ingress of air with the consequent formation of a flammable mixture.  [c.267]

Under normal operating conditions, waste is produced in reactors in six ways  [c.275]

Choice of reactor. The first and usually most important decisions to be made are those for the reactor type and its operating conditions. In choosing the reactor, the overriding consideration is usually raw materials efficiency (bearing in mind materials of construction, safety, etc.). Raw materials costs are usually the most important costs in the whole process. Also, any inefficiency in raw materials use is likely to create waste streams that become an environmental problem.  [c.400]

The generalized use of computers makes seemingly complex calculations quite easy to perform however, curves and tables are still invaluable when one needs to obtain approximate values or to take into account the sensitivity of a property to operating conditions or to a mixture s characteristics.  [c.85]

In order to adapt an engine to a given fuel of a given octane number, the automobile manufacturer must consider the design and control parameters in order to prevent knocking in all possible operating conditions the variables at hand are essentially the compression ratio and ignition advance which in turn determine the motor performance (thermal efficiency and specific horsepower). Horsepower can always be maintained by technological devices such as cylinder displacement and transmission ratios but the thermal efficiency always remains closely tied to the octane number. This is illustrated by the following example a 6-point increase in octane number (RON or MON) —corresponding to an average difference between a premium gasoline and a regular gasoline— enables a one-point gain in compression ratio (from 9 to 10, for example), which results in an efficiency improvement of 6%. An average 1% efficiency gain per point of octane number increase is thereby obtained. This approach has led to the concept of Car Efficiency Parameter (CEP). For an engine with a compression ratio exactly adapted to the fuel used, the CEP represents the weight per cent change in consumption resulting from a one-point change in octane number. In the preceding example, the CEP equals 1. That is the value most often used in economic evaluation of the technology. Now if the manufacturer changes the system acting on not the compression ratio but the ignition advance, the preceding tendency still applies but with a lower CEP, between 0.5 and 1. As a  [c.198]

To promote auto-ignition, especially under marginal operating conditions — cold starting, for example— a high compression ratio is necessary, generally between 15 and 22 according to the type of technology, e.g., direct or prechamber. This distinction along with other purely thermodynamic considerations such as average specific heat of the gases present in the cylinder, explain the generally high efficiency of the diesel engine.  [c.212]

L - Table 5.16 Gas oils fmm FCC (LCO). Effect of operating conditions on hydrotreated gas oil characteristics.  [c.225]

The implementation of very effective devices on vehicles such as catalytic converters makes extremely low exhaust emissions possible as long as the temperatures are sufficient to initiate and carry out the catalytic reactions however, there are numerous operating conditions such as cold starting and  [c.258]

Coking units are operated to optimize the light products produced, coke being considered as a by-product. Its quality is not too important. Generally speaking, the quality of coke produced varies widely according to the feed, the operating conditions, and the process.  [c.292]

Influence of operating conditions This concerns the temperature, the pressure and the residence time. The more severe the conditions are, the harder is the coke produced.  [c.292]

A detailed study of the properties of the potential products is of prime technical and economic importance, because it allows the refiner to have a choice in selecting feedstocks for his different units for separation, transformation and conversion, to set their operating conditions, in order to satisfy the needs of the marketplace in the best ways possible.  [c.315]

The graph gives the yields that the refiner would obtain at the outlet of the atmospheric distillation unit allowing him to set the unit s operating conditions in accordance with the desired production objectives.  [c.334]

The comparison between the qualities and quantities obtained and those for marketable products, the refiner can estimate the capacities and the operating conditions of the various treatment units  [c.335]

From these data, it is possible either to size a desulfurization unit, or to set the operating conditions for an existing unit.  [c.343]

One of the problems generally associated with the utilization of additives is the continuous action under the engine s operating conditions. That is particularly important for polymers that are sensitive to mechanical deterioration due to shear effects.  [c.355]

Drilling equipment and drilling activities have to be carried out in complex and often hostile environments. Surface and subsurface conditions may force the drilling rig and crew to operate close to their limits. Sometimes non-routine or unexpected operating conditions will exceed the rating of equipment and normal drilling practices may not be adequate for a given situation. Thus, drilling problems can and do occur.  [c.56]

The practising engineer has an excellent opportunity to influence the safety of operations by applying techniques such as hazard and operability studies (HAZOP) to the design of plant layout and equipment. This technique involves determining the potential hazard of an operation under normal and abnormal operating conditions, and considering the probability and consequences of an accident. This type of study is now commonly applied to new platform design and to the evaluation of refurbishment on existing platforms. Some examples of innovations in platform design which has resulted from this type of study are  [c.66]

Consideration of alternatives seeks to ensure that the proposer has considered other feasible options including location, scales, processes, layouts, operating conditions and the no action option.  [c.72]

Operating conditions all gas lift valves apart from the bottom orifice valve are closed. The energy to the system is delivered by a compressor. The performance of the system is monitored by observing flowrates and the casing and tubing pressures.  [c.232]

Gas turbine driven centrifugal compressors are very efficient under the right operating conditions but require careful selection and demand higher levels of maintenance than reciprocating compressors. Compression facilities are generally the most expensive item in an upstream gas process facility.  [c.253]

Crude oil and gas from offshore platforms are evacuated by pipeline or alternatively, in the case of oil, by tanker. Pipeline transport is the most common means of evacuating hydrocarbons, particularly where large volumes are concerned. Although a pipeline may seem a fairly basic piece of equipment, failure to design a line for the appropriate capacity, or to withstand operating conditions over the field life time, can prove very costly in terms of deferred oil production.  [c.272]

Artificial lift techniques are discussed in Section 9.6. During production, the operating conditions of any artificial lift technique will be optimised with the objective of maximising production. For example, the optimum gas-liquid ratio will be applied for gas lifting, possibly using computer assisted operations (CAO) as discussed in Section 11.2. Artificial lift may not be installed from the beginning of a development, but at the point where the natural drive energy of the reservoir has reduced. The implementation of artificial lift will be justified, like any other incremental project, on the basis of a positive net present value (see Section 13.4).  [c.339]

During the design phase, facilities (the hardware items of equipment) are designed for operating conditions which are anticipated based upon the information gathered during field appraisal, and upon the outcome of studies such as the reservoir simulation. The design parameters will typically be based upon assessments of  [c.341]

During the production period of the field, managing the surface facilities involves optimising the performance of existing production systems. The operating range of any one item of equipment will depend upon the item type (e.g. liquid-gas separator) and its selection at the design stage, but there will be maximum and minimum operating conditions, such as throughput. The minimum throughput may be described by the turndown ratio-.  [c.341]

Often a more common concern is the maximum capacity of the item of equipment, since optimising performance usually means maximising possible production. For an individual equipment item such as a separator, increases in the maximum capacity may be achieved by monitoring the operating conditions (e.g. temperature, pressure, weir height) and fine-tuning these conditions to optimise the throughput. This fine-tuning of specific items of equipment is ongoing, since the properties of the feed change over time, and is performed by the process engineer and the operator. Records of the operating conditions of the equipment items are kept to help to determine optimum conditions, and to indicate when the equipment is performing abnormally.  [c.341]

Acoustic Emission (AE) has been used as NDT method in a number of different applications covering a broad industrial range such as petrochemical industries, process monitoring, aerospace, welding, transformers and bearing testing " 1 Besides being a real time NDT method, the global nature of AE allows the inspection of large structures with a few sensors without scanning and without requiring access to the inside of the structure. The reduction of maintenance cost and the fact that AE succeeded in cases where other traditional NDT methods failed, made the AE widely accepted, specially in the petrochemical industries ". The application of AE succeeded in drastically decreasing the catastrophic failures of FRP pressure vessels and storage tanks and led major regulatory organisations to adopt AE in their codes and standards " . However most of the existing standards, adopt the philosophy of safe life design according to which the structure should not sustain any damage under normal operating conditions and the respective evaluation criteria give a pass/fail indication and not an assessment of structural integrity in terms of ranking defects criticality as required by the damage tolerance design philosophy .  [c.37]

Finally, preliminary diagnostic evaluation criteria, based on preventive identification of critical areas of interest on the monitored item, spatial concentration of localized AE events as compared with average AE event density and evolution of local event concentration vs time and/or plant parameters, have been worked out and submitted to extensive testing under real operation conditions. Work on this very critical issue is still to be consohdated.  [c.78]

Different plant operating conditions (steady load, load variations, startups / shutdowns) have been encountered during the monitoring period. Electrical load, steam pressure and steam temperature values vs time have been acquired and stored during the entire period. At the same time, the RMS values of the acoustical background noise were have been continuously checked and stored, thus providing a quick check of proper instrumentation condition and a correlation between variations of plant parameters and the acoustical behaviour of the components.  [c.78]

Examination of the cumulated histogram of localized AE sources for all monitoring intervals, in different operating conditions, suggests the conclusion that no structurally significant sources have been active in the monitored area of the SH header.  [c.78]

Of course, under the same operating conditions, the higher the thickness the lower the stress level. Further tests were carried out to map the surface thickness distribution using an ultrasonic precision thickness gauge. It was so verified a deviation of the thickness up to 10% of the nominal value.  [c.411]

Studying modem approaches for such schemes, one can see that knowledge of operational conditions and potential degradation mechanisms play a prominent role. Surprisingly, the role of NDT is often limited to tlie use of conventional methods such as ultrasonic wall thickness measurements, ultrasonic inspection, radiography, and last but not least visual inspection.  [c.949]

For NDT of new construction this implies that, the more one knows about the material properties and operational conditions, the better the acceptance criteria for weld defects can be based on the required weld integrity and fine-tuned to a specific application. In pipeline industry, this is already going to happen.  [c.951]

Different complete flowsheets can be evaluated by simulation and costing. On this basis, the flowsheet in Fig. 1.36 might be more promising than the flowsheets in Figs. 1.3a, 1.5a, and 1.56. However, we cannot be sure that we have the best flowsheet without first optimizing the operating conditions for each. The flowsheet in Fig. 1.56 might have greater scope for improvement than that in Fig. 1.36.  [c.4]

Catalytic incinerators. Cataljdic incinerators allow oxidation of wastes at lower temperatures than conventional thermal incinerators. Operating temperatures are less than 550" C. Their advantages are lower fuel consumption if auxiliary fuel is required and less severe operating conditions for materials of construction. However, catalytic incinerators cannot handle solid waste, and catalyst fouling and aging are a problem. Catalysts are usually noble metals (such as platinum or rhodium) finely divided on a support such as alumina. Both fixed and fluidized beds are used. The most common applications for catalytic incinerators are dedicated devices to treat gaseous process vents, particularly purges.  [c.300]

The major product is gasoline but gases and light and heavy gas oils are produced in proportions depending on feedstocks and operating conditions. The gasoline obtained is usually of a fairly high octane number due to the high proportion of unsaluraled hydrocarbons. See cracked gasoline.  [c.85]

A study is at present being carried out to check and validate the feasability of acoustic emission monitoring of the pneumatic testing of tanks. This study is being carried out in the context of the CIAPES program. This article gives only a brief summary of the results obtained on various materials, and different types of vessels, under different operating conditions.  [c.54]

The results of over 1 year of continuous, on-line acoustic emission (AE) structural surveillance of high temperature / high pressure steam headers, gained on 2 M-scale 600MW supercritical multifuel ENEL power units in normal operation, are presented in the paper. The influence of background noise, the correlation between plant operating conditions (steady load, load variations, startup / shutdown transients) and AE activity and the diagnostic evaluation of recorded AE events are also discussed.  [c.75]

See pages that mention the term Operating conditions : [c.3]    [c.5]    [c.9]    [c.78]    [c.114]    [c.230]    [c.79]    [c.1098]    [c.1099]   
See chapters in:

Chiral separation techniques  -> Operating conditions

Chiral separation techniques (2001) -- [ c.0 ]