Hydrocracking gases from

This reaction is endothermic and is favored by low pressure. In practice, however, the process is conducted at a pressure of 1-3 MPa (because of a concurrent hydrocracking reaction) and a temperature of 300-450°C using Pt-based catalysts [7]. The feedstock for the reforming process must be carefully purified from S- and N-compounds (below 1 ppm), which may use up a significant portion of hydrogen produced. The typical composition of the off-gas from the catalytic reforming of naphtha is as follows (vol%) H2—82, CH4—7, C2—5, C3—4, and C4—2 [7]. 

Refineries and petrochemical industry Paraffins, olefins, acetylenes, reformer gas, hydrocracking gas, solvents Sweetening of liquid petrol gas and aromatics, removal of CO2 from olefin containing gases, purification of synthesis gas Normal and branched-chain alkanes... 

TABLE II. - Analysis of gas from hydrocracking in situ crude... 

The fractionation equipment in a hydrocracker is generally carbon steel however, not all the sulfur has been removed. If the temperature will exceed 500° F (260° C), the sulfur content should be checked to determine whether SS is required. Severe corrosion of carbon steel has occurred in hydrocarbon fractionator furnace tubes and transfer lines as a result of the introduction of residual hydrogen sulfide in recycle gas from an amine unit. 

The aromatization of propane on supported (Si02/Al203)Ga, Zn or Pt catalysts is limited due to hydrocracking, dealkylation and hydrogen transfer reactions which lead to the formation of methane and ethane as the major products, and ethene and propene. However, the use of a Pd membrane reactor increases the yield of aromatics (e.g. benzene, toluene, Cg-Ci2 aromatics) dramatically by effective separation of the produced hydrogen gas from the reaction mixture by utilizing the H2 permeability of Pd thin films. 

The quality of the hydrogen-rich gas from the hydrogen plant is an important variable to the performance of Hydrocrackers since it can affect the hydrogen partial pressure and recycle gas/feed ratio and thereby influence the catalyst stability (deactivation rate). The following guidelines should be used in operating the hydrogen plant to produce acceptable feed gas to a Hydrocracker. 

More severe hydrotreating, such as mild hydrocracking at an H2 partial pressure of >6.9 MPa (1000 psig) and temperature of >400° C, can stiU further reduce sulfur content in the FCC feed. Mild hydrocracking of a 25° API VGO reduced the sulfur content of the FCC feed 98%, from 1.7 wt % to 0.03 wt % (40). This reduction can be expected to lower the SO content in the FCCU regenerator flue gas by about 90%. 

Shell Gas B.V. has constructed a 1987 mVd (12,500 bbhd) Fischer-Tropsch plant in Malaysia, start-up occurring in 1994. The Shell Middle Distillate Synthesis (SMDS) process, as it is called, uses natural gas as the feedstock to fixed-bed reactors containing cobalt-based cat- yst. The heavy hydrocarbons from the Fischer-Tropsch reactors are converted to distillate fuels by hydrocracking and hydroisomerization. The quality of the products is very high, the diesel fuel having a cetane number in excess of 75. 

Product separation for main fractionators is also often called black oil separation. Main fractionators are typically used for such operations as preflash separation, atmospheric crude, gas oil crude, vacuum preflash crude, vacuum crude, visbreaking, coking, and fluid catalytic cracking. In all these services the object is to recover clean, boiling range components from a black multicomponent mixture. But main fractionators are also used in hydrocracker downstream processing. This operation has a clean feed. Nevertheless, whenever you hear the term black oil, understand that what is really meant is main fractionator processing. 

Gas oil is a heavier petroleum fraction than kerosine. It can be obtained from the atmospheric distillation of crude oils (atmospheric gas oil, AGO), from vacuum distillation of topped crudes (vacuum gas oil, VGO), or from cracking and hydrocracking units. 

A major use of gas oil is as a fuel for diesel engines. Another important use is as a feedstock to cracking and hydrocracking units. Gases produced from these units are suitable sources for light olefins and LPG. Liquefied petroleum gas LPG may be used as a fuel, as a feedstock to... 

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