Feedstock using various

Since the early 1980s olefin plants in the United States were designed to have substantial flexibiHty to consume a wide range of feedstocks. Most of the flexibiHty to use various feedstocks is found in plants with associated refineries, where integrated olefins plants can optimize feedstocks using either gas Hquids or heavier refinery streams. Companies whose primary business is the production of ethylene derivatives, such as thermoplastics, tend to use ethane and propane feedstocks which minimize by-product streams and maximize ethylene production for their derivative plants. 

The feedstocks used ia the production of petroleum resias are obtaiaed mainly from the low pressure vapor-phase cracking (steam cracking) and subsequent fractionation of petroleum distillates ranging from light naphthas to gas oil fractions, which typically boil ia the 20—450°C range (16). Obtaiaed from this process are feedstreams composed of atiphatic, aromatic, and cycloatiphatic olefins and diolefins, which are subsequently polymerized to yield resias of various compositioas and physical properties. Typically, feedstocks are divided iato atiphatic, cycloatiphatic, and aromatic streams. Table 2 illustrates the predominant olefinic hydrocarbons obtained from steam cracking processes for petroleum resia synthesis (18). 

Other Markets. The use of methanol in the production of formaldehyde, MTBE, and acetic acid [64-19-7] accounts for approximately two-thirds of the worldwide demand for methanol. Methanol is used as feedstock for various other chemicals, such as dimethyl terephthalate (DMT)... 

Methanol and ethanol are alcohol fuels that can be produced from various renewable sources. Alcohol fuels are converted from biomass or other feedstocks using one or several conversion techniques. Both government and private research programs are finding more effective, less costly methods of converting biomass to alcohol fuels. Methanol was originally a by-product of charcoal production, but today it is primarily produced from natural gas and can also be made from biomass and coal. 

Toluene is a primary feedstock used to produce various organic compounds. It is used to produce diisocyanates. Isocyanates contain the functional group —N = C = O, and diisocyanates contain two of these. The two main diisocyanates are toluene 2,4-diisocyanate and toluene 2,6-diisocyanate. The production of diisocyanates in North America is close to a billion pounds annually. More than 90% of toluene diisocyanate production is used for making polyurethanes foams. The latter are used as flexible fill in furniture, bedding, and cushions. In rigid form it is used for insulation, hard shell coatings, building materials, auto parts, and roller skate wheels. 

The high temperature necessary for pyrolysis is obtained by burning fuel in excess air in a combustion chamber. Natural gas is still the fuel of choice, but other gases, e.g., coke oven gases or vaporized liquid gas, are occasionally used. Various oils including the feedstock are occasionally be used as fuel for economic reasons. Special burners, depending on the type of fuel, are used to obtain fast and complete combustion. 

In spite of all of the work, the kinetics and mechanism of alkyl-substituted dibenzothiophene, where the sulfur atom may be sterically hindered, are not well understood and these compounds are in general very refractory to hydrodesulfurization. Other factors that influence the desulfurization process such as catalyst inhibition or deactivation by hydrogen sulfide, the effect of nitrogen compounds, and the effect of various solvents need to be studied in order to obtain a comprehensive model that is independent of the type of model compound or feedstock used. 

Fermentation Results for Various Fibrous Feedstocks Using Ethanologenic Strain FBR5 ... 

Figure 1. Various feedstocks used for the production of maleic anhydride. Right, feedstock and left, product.

Characterization of Feedstock and Catalysts. The elemental analysis and physical properties of various feedstocks used in this study are given in Table I. The data show that the virgin bitumen contains... 

Filler coke is formed by the same general mechanism as that already described for binder coke. However, the feedstocks used are various petroleum residual fractions, instead of coal tar. Temperatures of 400-500°C convert these resids into green coke within a day. A complex series of endothermic pyrolysis reactions produce liquid-crystal mesophase which is transformed to a carbon polymer of generally graphitic structure. However, there are varying amounts of... 

Should MTBE be banned, what would be the logical replacement(s) There are several options available. Several refiners opted to build MTBE capacity and avoid purchasing the ether on the open market. MTBE units were an option to use the facility s isobutylenes. Several licensed processes can be used to convert existing MTBE units. Kvaerner and Lyondell Chemical Co. offer technologies to convert an MTBE unit to produce iso-octane, as shown in Fig. 18.27.12 Snamprogetti SpA and CDTECH also have an iso-octene/iso-octane process. These processes can use various feedstocks such as pure iso-butane, steam-cracked C4 raffinate, 50/50 iso-butane/iso-butene feeds, and FCC butane-butane streams. The process selectively dimerizes C4 olefins to iso-octene and then hydrogenates the iso-octene (di-iso-butene) into iso-octane. The processes were developed to provide an alternative to MTBE. The dimerization reactor uses a catalyst similar to that for MTBE processes thus, the MTBE reactor can easily be converted to... 

These benzaldehydes could then be directly used as a feedstock for various polymeric products or reduced to form phenolic benzylic alcohol derivatives (i.e., p-methylol groups). The p-methylol groups would thus be active sites, whereas in unmodified lignins, the C-l site is blocked and unreactive. In addition, the oxidative-cleavage step will hydrolyze a portion of the lignin interunit ether bonds, and thus increase the total fraction of free phenolic units to further enhance the reactivity. Other possible benefits are that the lignin would be extensively depolymerized and would form a more uniform feedstock material both conditions would give a product that is easier to handle. 

American Society of Mechanical Engineers Figure 10. Pyrolysis products comparison using various feedstocks (12)... 

Hydroprocessing is the conversion of various feedstocks using the physical aspects of temperature, residence time, and the presence of hydrogen under pressure. Hydroprocessing is more conveniently subdivided into hydrotreating and hydrocracking. 

Table 3.10 Comparision of Various Feedstocks Used in Ammonia Production [5]...

Direct Contact. There are several processes at various stages of development for conversion of heavy feedstocks to ethylene. These use various heat carriers and thereby avoid the problem of coke deposition in tubes which can be associated with thermally cracking residues by the more conventional route. This type of process is characterized by the use of moving beds, fluid beds, or gaseous heat carriers. Typical of these processes are the developments of Hoechst, Lurgi, BASF, Unde, etc. (4, 6). 

The advantages of using a liquid-phase process include low heating cost, the feasibility of using various catalysts, and easy separation of oil products from the aqueous phase. The drawback is that the biomass feedstocks need to be purified. A comprehensive description of reactions that occur in liquid phase processing can be found in others reviews. ... 

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