Refining scenario

In Chapter one, we have introduced our view of the current refining scenario extrapolation from this may lead to a view of the future scenario. However, the oil refining scenario might be different if a holistic view of the fuel manufacturing business is considered. 

The refining scenario we described in Chapter 1 considers fossil-derived fuel in a market where supplied oil is becoming heavier and environmental specifications are becoming increasingly stringent. This scenario resulted in the oil-derived fuels and the biofuels... 

Refining conventional feedstocks presumes that the distillation is the first pretreatment process applied to a feedstock. Application of distillation as a separation to heavy feedstocks is a moot point, often being considered economically unnecessary and of little benefit to the refining scenario. Processes that receive consideration to separate the residuum include deasphalting as well as thermal treatment. These options have not been accepted for wide use because of increased cost or because they recover low-value portions of the feedstock that must be used or disposed of at some stage of the refining operation. Nevertheless, some consideration is worthy of note here because of the potential for such concepts in the future. 

Using the techniques referenced in Section 5.2, a detailed list of potential accident scenarios can be prepared. This list can then be refined to give the minimum number of scenarios that need to be assessed to adequately reflect the spectrum of possible incidents and to satisfy the requirements of the study. The steps involved may include ... 

It is advisable, then, in a tiered approach to concentrate first on crops and activities (scenarios) that are considered to be relevant with respect to the expected level of exposure and to exclude those not relevant. Second, whether or not the toxicological properties of the product may lead to general restrictions on re-entry should be investigated. If both the likelihood of reentry and the hazard due to the toxicity of the compound cannot generally be neglected, a risk assessment over several steps should be carried out. The assessment may be based on surrogate data and "worst-case" assumptions at first and then refined, if necessary. One possible approach to a tiered evaluation procedure is presented in Figure 1. 

As it has been shown in this chapter knowing the concentrations of chemicals in the environment is a key aspect in order to carry out meaningful hazard and risk assessment studies. Predicting concentrations of chemicals can serve as a quick and robust way to produce an acceptable screening level assessment however if further precision is desired, the complexity of real environmental scenarios can make it a cumbersome and unaffordable task. Models improvement requires not only refining their computation algorithms but also and more important, implementing new inputs and processes in order to better describe real scenarios. 

The time taken for biotechnological developments in oil refining has been, so far, very long. However, it should be noted that the MB and GE advances have only been recent and the magnitude of involvement and efforts by the oil industry itself has not been substantial. Assuming a more proactive involvement of the oil industry, the incorporation of modern tools and the building of the much needed multidisciplinary team, the developmental time should decrease. Nevertheless, any current development has to be oriented to address the issues that will come up in stated future scenarios, such as the integrated bio-oil-refineries of the future. 

In the action sequence diagram in Figure 4.15, each main vertical bar is an object. (It is not a type If there are several objects of the same type in a scenario, that means several bars.) Each horizontal bar is an action. Actions may possibly be refined to a more-detailed series of actions—perhaps differently for different subtypes or in different implementations. The elliptical bubbles mark the participants in each action there may be several. If there is a definite initiator, it is marked with a shaded bubble. 

An abstract action, together with a refinement, is called a use case. The story accompanying the event chart is called a scenario. Some tools can show the breakdown of the video store into its internal parts directly in the event chart others make you show it in a separate diagram. 

The next thing my code reviewer notices is that nowhere is there a function setSum(C ell, C elJ jl explain that I have decided to refine this action to a finer-grained series of interactions between the user and the spreadsheet (see Figure 6.19 earlier). To set a cell to be the sum of two others as per requirement, the user performs this scenario ... 

You can model the system context, and corresponding scenarios, system type model, and action specs, at any consistent level of granularity. The actions should be refined to the level where completion of the action accomplishes an atomic transaction with the system, and must be completed in its entirety by the actor to be meaningfully handled by the system. 

The Ph.D. thesis of D. Beringer [Beringer97] generalizes the concept of scenarios in that context, it has a good discussion of refinement (action and object refinement), good ideas about the systematic depiction of scenario types, and a brief, insightful, discussion of the need for more-effective state abstraction. 

Several recovery scenarios were considered for remediation. Initially, construction of a narrow, permeable trench parallel to the canal appeared to be an appropriate interception system. The construction technique considered was use of a specially designed deep trenching unit. This type of trench would have included a tile drain leading to a single two-pump recovery well. However, a review of the subsurface site plans and interviews with long-term employees determined that an unknown number of buried pipes traverse the area intended for the trench construction. Disruption of refining operations and safety considerations resulted in rejection of this option. 

The appropriate level of personal protection necessary to safely perform the site characterization activities will depend on the assessment of site hazards that might pose a risk to the site characterization team. The hazard assessment may be further refined during the approach to the site, based on the results of the field safety screening and initial observations of site conditions. Two general scenarios are considered, one in which there are no obvious signs of immediate hazards, and one in which there are indicators of site hazards. 

A collection of scenarios is generated that best captures the trend of raw material prices of the different types of crude oil and the sales prices of the saleable refining products for a representative period of time based on available historical data. A probability ps, with index s denoting the sth scenario, is assigned to each scenario to reflect the likelihood of each scenario being realized with ps = 1. 

Finally, if the registrant can prove that all risks are under control and the substance can be safely manufactured and used, the corresponding initial exposure scenario is defined as the final exposure scenario. In the end, the final exposure scenario is communicated within the framework of extended safety data sheets in order to ensure the safe use of the substance down the supply chain (Caveat The legal text of REACH usually refers to the term exposure scenario while in reality speaking of the final exposure scenario.) By contrast, if the registrant fails to lower the risk characterization ratio below 1, despite the aforementioned refinements and modifications, he must prevent the use of the substance under circumstances where the risks are not controlled. 

The development of exposure scenarios is an iterative process if, using the initial assumptions, the estimated exposure is greater than the no-effect level, the exposure scenario should be amended by altering the conditions in which the chemical is to be used. The hazard assessment may also be refined, for example by generation of more data on the hazards (Regulation (EC) 1907/2006, Annex I, paragraph 5.1.1). The aim of the CSA is not to decide whether there is a risk or not, but to describe, in the exposure scenario, how the chemical can be used so that risks are adequately controlled. 

The production of domestic sulfur values (elemental recovered sulfur and the sulfur content of acid) will total about 18 million long tons per year by the year 2000. By region (Petroleum Administration for Defense districts), except for the east coast (PAD I), there will be no deficit areas in the U. S. Major contributors are sour natural gas and the refining of heavier, sour, crude oil. Proximate, scenario dependent sources, are electric utilities and coal-based synfuels. Shale oil, domestic tar sands and heavy oil, and unconventional sources of natural gas will be small suppliers. 

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