Refineries products, properties

In terms of chemicals legislation substances are elements or compounds in the natural state or obtained by any production process, including any additive necessary to preserve the stability of the products and any impurity from the process used. A substance (as determined by its CAS or EINECS number) may be a desired combination of products from a chemical reaction or a distillation fraction (in refinery products) and/or may contain urrdesired impurities. This means that the same substance may indeed exhibit differerrt properties. 

A comparison has been made of Platforming and of thermal reforming from the standpoint of yield-octane number relationships, product properties, hydrocarbon types, and with respect to the nature of chemical reactions responsible for improvement of octane number. Comparison is based on studies of thermal reforming in a commercial operation at a Pennsylvania refinery and in a pilot plant on a midcontinent naphtha and in pilot plants and laboratory Platforming on the same stocks. 

The database for these refinery LP models is a mixture of economic and technical inputs. Economic inputs include the availability and price of refinery raw materials, the variable cost of operating the individual process units, and the demand and price for refinery products. Technical inputs include refinery product specifications as well as the operating constraints, usage of equipment and utilities, product yields, and product properties for each process unit. 

To facilitate the maintenance and updating of plant performance inputs, we have developed and implemented an LP preprocessor. This preprocessor automatically generates and stores in the LP database the usage of equipment and utilities, the product yields, and the product properties for six process units at Sun Petroleum Products Company s Toledo Refinery. Linked to the preprocessor are three already existing process simulators a fluid catalytic cracker or FCC simulator, a hydrocracker simulator, and a catalytic reformer simulator. 

Gebauer et al. [38] suggest visbreaking of waste plastics with vacuum residue. This is a thermal process, applied in refineries in order to convert partially atmospheric vacuum residue and decrease viscosity and melting temperature. According to the authors, addition of 5% of waste plastics in laboratory tests does not influence noticeably the process parameters and final products properties. As in the case of LCO and VGO fractions the application of vacuum residue and mixture of waste plastics is applicable in refineries. 

The main improvement of the Ecofining technology compared to the conventional FAME biodiesel is that it allows refiners to obtain a synthetic fuel that has a similar chemical composition and similar chemical-physical properties to petroleum diesel. For this reason the product can all be easily blended with conventional refinery products. Moreover, the integrated production of the green diesel allows the refiner to... 

Continuity of properties of components. A large number of components leads to the fact that dependence of properties of components on their normal bubble temperature is continuous. Therefore, in practice, while designing one deals not with the true components but with pseudocomponents (i.e., with groups of components boiling away in a set interval of temperatures), and the quality of the products is characterized not by their purity but by their refinery inspection properties. 

In addition thermophysical properties required for modeling purposes, a complete model must also make predictions regarding several fuel properties routinely measured at the refinery. Typically these fuel or product properties include measurements such as flash point, freeze point, cloud point and paraffin-naphthene-aromatic (PNA) content. These properties not only serve as indicators of product quality and distribution, but may also be limited by government or internal refinery regulations. We can often justify the use of process modeling in the refinery by making sure that models also include predictions of these useful fuel properties. We will briefly discuss two approaches in this area and give concrete examples with flash point, freeze point and PNA content We choose these particular properties because they display characteristics common to many types of fuel property correlation methods. We refer the reader to API standards [35] and Riazi [4] for more detailed expositions on various types of correlations for fuel properties not discussed in this section. 

It is the heteroelements that can have substantial effects on the distribution of refinery products. Coupled with the changes brought about to the feedstock constituents by refinery operations, it is not surprising that refining the heavy feedstocks is a monumental task. Thus, initial inspection of the feedstock (conventional examination of the physical properties) is necessary. From this, it is possible to make deductions about the most logical means of refining. In fact, evaluation of crude oils from physical property data as to which refining sequences should be employed for any particular crude oil is a predominant part of the initial examination of any material that is destined for use as a refinery feedstock. 

Urea has the remarkable property of forming crystalline complexes or adducts with straight-chain organic compounds. These crystalline complexes consist of a hoUow channel, formed by the crystallized urea molecules, in which the hydrocarbon is completely occluded. Such compounds are known as clathrates. The type of hydrocarbon occluded, on the basis of its chain length, is determined by the temperature at which the clathrate is formed. This property of urea clathrates is widely used in the petroleum-refining industry for the production of jet aviation fuels (see Aviation and other gas-TURBINE fuels) and for dewaxing of lubricant oils (see also Petroleum, refinery processes). The clathrates are broken down by simply dissolving urea in water or in alcohol. 

Crude oil is a mixture of many different hydrocarbons and small amounts of impurities. The composition of crude oil can vary significantly depending on its source. Petroleum refineries are a complex system of multiple operations and the operations used at a given refinery depend upon the properties of the crude oil to be refined and the desired products. For these reasons, no two refineries are alike. Portions of the outputs from some processes are re-fed back into the same process, fed to new processes, fed back to a previous process, or blended with other outputs to form finished products. The major unit operations typically involved at petroleum refineries are described briefly below. In addition to those listed below, there are also many special purpose processes that cannot be... 

All refining operations may be classed as either conversion processes or separation processes. In the former, the feed undergoes a chemical reaction such as cracking, polymerization, or desulfurization. Separation processes take advantage of differences in physical properties to split the feed into two or more different products. Distillation, the most common of all refinery separation processes, uses differences in boiling points to separate hydrocarbon mixtures. 

The machinery employed in the early refineries was rather small in scale and operated iiiefficieutly. Generally, equipment consisted of a series of shell tubes or stills. These were placed in the horizontal position and were connected one to another from the top through the use of vapor pipes. These pipes directed the vapors from the stills into condensers which cooled the gases and so caused the products to separate out. These products were then collected in sequence, often at one point in the plant, as liquids of varying densities and properties. 

Natural gas and crude oils are the main sources for hydrocarbon intermediates or secondary raw materials for the production of petrochemicals. From natural gas, ethane and LPG are recovered for use as intermediates in the production of olefins and diolefms. Important chemicals such as methanol and ammonia are also based on methane via synthesis gas. On the other hand, refinery gases from different crude oil processing schemes are important sources for olefins and LPG. Crude oil distillates and residues are precursors for olefins and aromatics via cracking and reforming processes. This chapter reviews the properties of the different hydrocarbon intermediates—paraffins, olefins, diolefms, and aromatics. Petroleum fractions and residues as mixtures of different hydrocarbon classes and hydrocarbon derivatives are discussed separately at the end of the chapter. 

Trend the feedstock properties look for changes in the K factor, 1,050°F+ (565°C+), aniline point, refractive index, and °API gravity. The feed endpoint may have been increased to fill the unit. The conversion penalty may be a small price to pay for the increased capacity, but the penalty can be minimized. Verify that the refinery LP reflects current data on yields and product quality. 

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