Diesel conversion

Figure 1 System boundary of diesel conversion process (dotted line indicates system boimdary)...

Data of biodiesel production from Ecoinvent database is used for a typical production process. Rapeseed oil harvest is included covering biomass growth, application of fertilization, pesticides, agricultural machineries, harvest and transportation to a diesel production plant within 200km. Diesel conversion process covers the conversion process and its irtiUties as well as the life cycle of the plantation facilities. 

In ReCiPe assessment methods, three types of ecotoxicity are considered including terrestrial, freshwater and marine ecotoxicity. Terrestrial ecotoxicity is dominated by pesticide emissions to agriculture soil as well as the use of both sulphuric acid and steam during the conversion process. Marine ecotoxicity is fully dominated by emissions of heavy metals and sulphuric acid, largely to air. In the case of the GTE diesel conversion process presented in this paper, the characterization results shows... 

S/C = 3 and O/C = 1. While diesel conversion was stable over the catalyst, a certain deactivation became obvious, owing to the decreasing content of hydrogen and the increasing content of carbon monoxide present in the reformate. 

All modern refineries have conversion units, designed to transform black effluent streams into lighter products gas, gasoline, diesel fuel. Among these conversion units, coking processes take place by pyrolysis and push the cracking reaction so far that the residue from the operation is very heavy it is called coke . 

In a single stage with liquid recycle, total conversion to products lighter than the feedstock is possible. The yield of kerosene plus diesel is between 70 and 73 weight %. 

The flowscheme of the typical refinery during the period 1950-1970 was essentially focused on the production of gasoline, diesel oil, domestic heating oil and industrial fuel-oil. Except for heavy naphtha, the product streams underwent no deep conversion. 

Heavy residue conversion is linked to the demand for high quality diesel motor fuel (aromatics content 10%, cetane number 55) as well as to the demand for production of light fuel-oil having very low sulfur, nitrogen and metal contents. 

The products could be classified as a function of various criteria physical properties (in particular, volatility), the way they are created (primary distillation or conversion). Nevertheless, the classification most relevant to this discussion is linked to the end product use LPG, premium gasoline, kerosene and diesel oil, medium and heavy fuels, specialty products like solvents, lubricants, and asphalts. Indeed, the product specifications are generally related to the end use. Traditionally, they have to do with specific properties octane number for premium gasoline, cetane number for diesel oil as well as overall physical properties such as density, distillation curves and viscosity. 

We cite isomerization of Cs-Ce paraffinic cuts, aliphatic alkylation making isoparaffinic gasoline from C3-C5 olefins and isobutane, and etherification of C4-C5 olefins with the C1-C2 alcohols. This type of refinery can need more hydrogen than is available from naphtha reforming. Flexibility is greatly improved over the simple conventional refinery. Nonetheless some products are not eliminated, for example, the heavy fuel of marginal quality, and the conversion product qualities may not be adequate, even after severe treatment, to meet certain specifications such as the gasoline octane number, diesel cetane number, and allowable levels of certain components. 

In shape-selective catalysis, the pore size of the zeoHte is important. For example, the ZSM-5 framework contains 10-membered rings with 0.6-nm pore size. This material is used in xylene isomerization, ethylbenzene synthesis, dewaxing of lubricatius oils and light fuel oil, ie, diesel and jet fuel, and the conversion of methanol to Hquid hydrocarbon fuels (21). 

The sources of particulate matter in the atmosphere can be primary, directly injected into the atmosphere, or secondary, formed in the atmosphere by gas-to-particle conversion processes (13). The primary sources of fine particles are combustion processes, e.g., power plants and diesel... 

As an alternate to LNG, natural gas can be chemically converted to methanol, chemical feedstocks (such as ethylene), gasoline, or diesel fuel. Most processes start with the conversion of methane to synthesis gas, a mixture of carbon monoxide and hydrogen. This can be done partial oxidation, an exothermic reaction ... 

Power unit manufacture also produce diesel engines that can be converted to operate on a dual fuel carburation of about 10% diesel and natural gas. Such conversions are more difficult than converting spark-ignition engines to various gas fuels. 

The thermal power plant uses a fired boiler for conversion of fuel to heat. It can be said that there is a design of fired boiler to suit almost all types of fuels, including wastes and vegetable and industrial byproducts. Generally, for oils and gases these can be more readily converted to power in diesels or gas turbines and would not be considered for thermal power plant, unless the station was of significant size. 

The preceding section reviewed the application of popular prime movers for the generation of electrical power only. In the conversion of fuel energy to electricity it is shown that heat is rejected, either in the exhaust of a diesel or gas turbine or, alternatively, in the condenser of a thermal power plant. It can be seen that by applying these machines to provide both heat and electricity the total energy recovery can be much greater and efficiency thereby improved. Combined heat and power (CHP) schemes of this nature are well-established methods of producing both heat and power efficiently and economically. 

The high efficiency of conversion of the diesel generator immediately restricts its potential improvement compared with gas turbines. With the simple addition of a boiler, the gas turbine can give a heat/power ratio of 2 1 compared with the diesel s 0.6 1. (The diesel heat/power... 

For the criterion of fuel to electrical energy conversion efficiency, the diesel and gas turbine are natural choices for prime fuels such as oil and gas. 

The main pollutants in Diesel exhausts are NOx and particulate matter (PM), mostly soot, with lesser amounts of CO and light hydrocarbons (CH). Table 12.1 shows the corresponding emission standards in Europe and in the USA. These standards are becoming progressively stricter and Table 12.2 shows the needed conversion efficiency of the electrochemically promoted unit in order to meet the EUR04 2005 standards. 

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