Feedstock hydrocarbon

This section is based on natural gas feedstock. With natural gas, all technologies are technically viable. However, if the feedstock is a heavy hydrocarbon (such as fuel oil or vacuum bottoms), the POX is the only viable technology. This is because the other technologies cannot process feedstocks heavier than naphtha (to avoid carbon deposition on the catalyst). 

The importance of the product H2/CO ratio has already been discussed extensively. As previously stated, the technology that offers a natural ratio that spans the required product ratio is considered to have an inherent advantage and must be seriously considered. 

---

Hydrocarbon cracking Hydrocarbon feedstocks Hydrocarbon oils Hydrocarbon oxidation Hydrocarbon polymers... 

Olefins are produced primarily by thermal cracking of a hydrocarbon feedstock which takes place at low residence time in the presence of steam in the tubes of a furnace. In the United States, natural gas Hquids derived from natural gas processing, primarily ethane [74-84-0] and propane [74-98-6] have been the dominant feedstock for olefins plants, accounting for about 50 to 70% of ethylene production. Most of the remainder has been based on cracking naphtha or gas oil hydrocarbon streams which are derived from cmde oil. Naphtha is a hydrocarbon fraction boiling between 40 and 170°C, whereas the gas oil fraction bods between about 310 and 490°C. These feedstocks, which have been used primarily by producers with refinery affiliations, account for most of the remainder of olefins production. In addition a substantial amount of propylene and a small amount of ethylene ate recovered from waste gases produced in petroleum refineries. 

The two primary types of plastics, thermosets and thermoplastics, are made almost exclusively from hydrocarbon feedstocks. Thermosetting materials are those that harden during processing (usually during heating, as the name implies) such that in their final state they are substantially infusible and insoluble. Thermoplastics may be softened repeatedly by heat, and hardened again by cooling. 

Taking into account the purification losses, the following operating requirements are necessary in order to obtain 100 kg of purified acetylene 200 kg hydrocarbons (feedstock plus quench), 1030 kWh electric energy for the arc, 250 kWh electric energy for the separation unit, and 150 kg steam. 

The total number of reactions depends on the number of constituents present in the hydrocarbon feedstock. As many as 2000 reactions can occur simultaneously. 

Steam Reforming Processes. In the steam reforming process, light hydrocarbon feedstocks (qv), such as natural gas, Hquefied petroleum gas, and naphtha, or in some cases heavier distillate oils are purified of sulfur compounds (see Sulfurremoval and recovery). These then react with steam in the presence of a nickel-containing catalyst to produce a mixture of hydrogen, methane, and carbon oxides. Essentially total decomposition of compounds containing more than one carbon atom per molecule is obtained (see Ammonia Hydrogen Petroleum). 

Table 8. Best-Suited Developing Technology for Various Low Hydrocarbon Feedstocks...

Carbon Blacks. Carbon blacks are occasionally used as components in mixes to make various types of carbon products. Carbon blacks are generally prepared by deposition from the vapor phase using petroleum distillate or gaseous hydrocarbon feedstocks (see Carbon, carbon black). 

Chlorination of various hydrocarbon feedstocks produces many usehil chlorinated solvents, intermediates, and chemical products. The chlorinated derivatives provide a primary method of upgrading the value of industrial chlorine. The principal chlorinated hydrocarbons produced industrially include chloromethane (methyl chloride), dichloromethane (methylene chloride), trichloromethane (chloroform), tetrachloromethane (carbon tetrachloride), chloroethene (vinyl chloride monomer, VCM), 1,1-dichloroethene (vinylidene chloride), 1,1,2-trichloroethene (trichloroethylene), 1,1,2,2-tetrachloroethene (perchloroethylene), mono- and dichloroben2enes, 1,1,1-trichloroethane (methyl chloroform), 1,1,2-trichloroethane, and 1,2-dichloroethane (ethylene dichloride [540-59-0], EDC). 

The hydrocarbon feedstock contains 35—95% ethylene the remaining gases are methane and ethane. Certain unsaturated hydrocarbons are undesirable as their presence leads to the formation of secondary alcohols. 

Adiabatic Cracking Reactor. This principle is based on the injection of hydrocarbon feedstock into the flue gas at elevated temperatures. 

The need for highly cost-efficient oxygen transfer in fermentations such as those with hydrocarbon feedstocks has led to air-hft fermenters as shown in Fig. 24-4. The worlds largest industrial fermenter was... 

Ammonia (NHj) is produced from atmospheric nitrogen and hydrogen from a hydrocarbon source. Natural gas is the most commonly used hydrocarbon feedstock for new plants other feedstocks that have been used include naphtha, oil, and gasified coal. Natural gas is favored over the other feedstocks from an environmental perspective. 

Figure 8.3.1 is a typical process diagram for tlie production of ammonia by steam reforming. Tlie first step in tlie preparation of tlie synthesis gas is desulfurization of the hydrocarbon feed. Tliis is necessary because sulfur poisons tlie nickel catalyst (albeit reversibly) in tlie reformers, even at very low concentrations. Steam reforming of hydrocarbon feedstock is carried out in tlie priiiiiiry and secondary reformers. 

Ionic liquid-catalyzed polymerization of butene is not limited to the use of pure alkene feedstocks, which can be relatively expensive. More usefully, the technology can be applied to mixtures of butenes, such as the low-value hydrocarbon feedstocks raffinate I and raffinate II. The raffinate feedstocks are principally C4 hydrocarbon mixtures rich in butenes. When these feedstocks are polymerized in the presence of acidic chloroaluminate(III) ionic liquids, polymeric/oligomeric products with... 

Since plastics are generally made from hydrocarbon feedstocks they should be recycled to conserve energy. The most effectives energy conservation is to refabricate plastic items, though this is not always technically feasible. Under circumstances where recycling is not a feasible option the use of plastics in waste-derived fuels may be an acceptable conservation measure. 

By cooling the gas is condensed and then available as hydrocarbon feedstock for other processes (some 85% of the MPW input). The light hydrocarbon gas (15% of the MPW input) that remains after cooling is compressed, reheated and returned to the reactor as fluidising gas. It can also be used as a fuel for the cracking process, though other recovery options are being studied as well. 

Steam reforming was developed in Germany at the beginning of the 20th century, to produce hydrogen for ammonia synthesis, and was further introduced in the 1930s when natural gas and other hydrocarbon feedstocks such as naphtha became available on a large scale. 

Carbon blacks are manufactured from hydrocarbon feedstocks by partial combustion or thermal decomposition in the gas phase at high temperatures. World production is today dominated by a continuous furnace black process, which involves the treatment of viscous residual oil hydrocarbons that contain a high proportion of aromatics with a restricted amount of air at temperatures of 1400-1600 °C. 

Kaufman, E. N. Harkins, J. B., and Borole, A. P., Comparison of Batch-Stirred and Electro-Spray Reactors for Biodesulfurization of Dibenzothiophene in Crude Oil and Hydrocarbon Feedstocks. Applied Biochemistry and Biotechnology, 1998. 73(2-3) pp. 127-144. 

ER E, the S T organization of the World largest oil company, ExxonMobil, was not very prolific in R D activities related to biocatalytic refining, but was focused on addressing a few key problems identified in BDS. They began in early 1990, with works on gas treatment however, the developments took an oil twist towards the end of the decade when they became involved with heavier hydrocarbon feedstocks. This company possesses inventions, which are protected with six patents ... 

The production of synthesis gas based on heterogeneous catalytic reactions using 02 (air) as an oxidant is referred to as catalytic POx (CPO). Although the process is potentially able to process a wide range of hydrocarbon feedstocks, including heavy hydrocarbons, most of the information in the literature relates to the CPO of methane (or NG). The CPO of methane can be presented by the following equation ... 

Figure 2.10 provides a thermodynamic equilibrium molar fraction of the products of CPO of methane as a function of temperature. It is evident that at temperatures above 800°C, hydrogen and CO (in molar ratio of 2 1) are two major products of the reaction. The oxidant (oxygen or air) and the hydrocarbon feedstock (e.g., methane) are premixed in a mixer... 

---