Properties of Liquid Product

The need for various grades of the product oils separated in the distillation tower is evident. In order to keep the various grades on a uniform basis, the authorities in each country have standardized on a few grades by the properties of the oil produced. 

It is necessary to compare reliable properties of the oil produced, as a comparison with those of commercial gasoline, kerosene and diesel. It is essential to determine the physical measurements such as those listed for a variety of the oils, as shown in Table 5.5. Based on these values, the oil produced in the process plant is tested, to determine whether it can be put on the market. 

As the density of the oil produced is decreased, the heat value per volume decreases, but the heat value per mass will increase. If the oil is usually purchased and sold on a volume basis, heavy oil is more efficient. Also, if it is necessary to choose the most important specific of the oil produced, viscosity will be selected. Viscosity can aid combustion and can also be the cause of the greatest trouble. For proper and efficient combustion an oil should have a reasonable viscosity at the burner. In the case of too high viscosity, difficulty in pumping in the process and trouble at the burner are encountered and also carbon residue is high due to poor combustion. However, in case of too light oil, incomplete combustion occurs and there will be a loss of economy. 

Further sources of trouble with the oil produced is water and sediment present in the oil, when it is used as a fuel oil. Water causes sparking, spitting and flashback of the flame, which result in loss of heat as a result of improper combustion. Sediments such as sand and carbon, etc. cause the erosion of burner tips, pump parts and sensitive control valves, etc. Also, some chemical compounds present in an oil will absorb oxygen from air or water, to form new compounds. Unfortunately, some of these chemical compounds are insoluble in the oil, with the result that they will either remain suspended in the oil or will drop to the bottom of the tank. They must not reach the suction lines in a storage tank. 

When discussing the oil produced, the subject of carbon becomes an issue. Carbon is formed during cracking of hydrocarbons at high temperature and pressure. This carbon is present in heavy oil and will be suspended within the oil. However, oil containing a small amount of carbon is easily combustible without any trouble. The carbon content is 

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The module OUTPUT generates a report (Tables XIV-XVII) summarizing input data, reactor operating conditions, product yields, properties of liquid products, recycle gas composition, and hydrogen production. Also, temperature and composition profiles are generated. 

Table 18.7 Product yields and properties of liquid product from PVC mixed PP/PE/PS plastic degradation using Ca-C (6 consecutive runs) and thermal degradation. (Reproduced with permission from the American Chemical Society)...

Table 18.9 Product yields and properties of liquid products from PP/PE/PS/PVC/HIPS-Br degradation at 430°C in the absence and presence of Ca-C sorbent (weight ratio PP PE PS PVC HIPS-Br = 3 3 2 1 1). (Reproduced with permission from The Royal Society of Chemistry)...

Table 18.10 Products yield and properties of liquid product from 3P/PVC, 3P/PVC/PET and MWP (20 g) thermal degradation at 430°C. (Reproduced with permission from Elsevier)...

The physical properties of spray-dried materials are subject to considerable variation, depending on the direction of flow of the inlet gas and its temperature, the degree and uniformity of atomization, the solids content of the feed, the temperature of the feed, and the degree of aeration of the feed. The properties of the product usually of greatest interest are (1) particle size, (2) bulk density, and (3) dustiness. The particle size is a function of atomizer-operating conditions and also of the solids content, liquid viscosity, liquid density, and feed rate. In general, particle size increases with solids content, viscosity, density, and feed rate. 

A useful property of liquids is their ability to dissolve gases, other liquids and solids. The solutions produced may be end-products, e.g. carbonated drinks, paints, disinfectants or the process itself may serve a useful function, e.g. pickling of metals, removal of pollutant gas from air by absorption (Chapter 17), leaching of a constituent from bulk solid. Clearly a solution s properties can differ significantly from the individual constituents. Solvents are covalent compounds in which molecules are much closer together than in a gas and the intermolecular forces are therefore relatively strong. When the molecules of a covalent solute are physically and chemically similar to those of a liquid solvent the intermolecular forces of each are the same and the solute and solvent will usually mix readily with each other. The quantity of solute in solvent is often expressed as a concentration, e.g. in grams/litre. 

Iron (II) oxide and especially that made by reducing the other oxides, combusts spontaneously if it is heated to 200°C. It also strongly catalyses the combustion of carbon in air. This behaviour can explain the spontaneous inflammable property of the products of burning iron oxalate, which contain this oxide and carbon. When they are placed on the hand and thrown into the air, they form very spectacular showers of sparks. It combusts in contact with liquid oxygen in the presence of carbon. 

The predominant methods of measuring the properties of petroleum products are covered by approximately seven test methods used in the determination of bnlk qnantities of liquid petroleum and its products (ASTM D96, D287, D1085, D1086, D1087, D1250, D1298). 

A wide variety of liquid products are produced from petroleum, that varying from high-volatile naphtha to low-volatile lubricating oil (Guthrie, 1967 Speight, 1999). The liquid products are often characterized by a variety of techniques including measurement of physical properties and fractionation into group types (Chapter 7). 

The impact of the release of liquid products on the environment can, in part, be predicted from knowledge of the properties of the released liquid. Each part of an ocular liquid product from petroleum has its own set of unique analytical characteristics (Speight, 1999, 2002). Since these are well documented, there is no need for repetition here. The decision is to include the properties of the lowest-boiling liquid product (naphtha) and a high-boiling liquid product (fuel oil). For the properties of each product (as determined by analysis) a reasonable estimate can be made of other liquid products, but the relationship may not be linear and is subject to the type of crude oil and the distillation range of the product. 

Density (the mass of liquid per unit volume at 15°C) and the related terms specific gravity (the ratio of the mass of a given volume of liquid at 15°C to the mass of an equal volume of pure water at the same temperature) and relative density (same as specific gravity) are important properties of petroleum products as they are a part of product sales specifications, although playing only a minor role in studies of product composition. Usually, a hydrometer, pycnometer, or digital density meter is used for determination in all these standards. 

The catalytic cracking of four major classes of hydrocarbons is surveyed in terms of gas composition to provide a basic pattern of mode of decomposition. This pattern is correlated with the acid-catalyzed low temperature reverse reactions of olefin polymerization and aromatic alkylation. The Whitmore carbonium ion mechanism is introduced and supported by thermochemical data, and is then applied to provide a common basis for the primary and secondary reactions encountered in catalytic cracking and for acid-catalyzed polymerization and alkylation reactions. Experimental work on the acidity of the cracking catalyst and the nature of carbonium ions is cited. The formation of liquid products in catalytic cracking is reviewed briefly and the properties of the gasoline are correlated with the over-all reaction mechanics. 

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