Reformer operation

Three different reactor systems have evolved since the process was first introduced in 1952  

Dehydrogenation Naphthenes to aromatics (e g., methylcyclohexane to toluene) Exfremely endothermic 

Isomerization Normal paraffins to branched paraffins Mildly exothermic 

Note From Mills, Heinemann, Milliken and Oblad, Ind. and Eng. Chemistry, 1953. 

Since the first catalytic reformers were used in the 1950s the hydrogen/ hy-drocaibon mole ratio and the reformer operating pressure have both been gradually decreased. These developments resulted from improvements in the alumina support, the use of bimetallic catalysts, and finally the introduction of the low-pressure, continuous catalyst regeneration processes. The trends in operation are shown in Table 6.18. 

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Naphtha desulfurization is conducted in the vapor phase as described for natural gas. Raw naphtha is preheated and vaporized in a separate furnace. If the sulfur content of the naphtha is very high, after Co—Mo hydrotreating, the naphtha is condensed, H2S is stripped out, and the residual H2S is adsorbed on ZnO. The primary reformer operates at conditions similar to those used with natural gas feed. The nickel catalyst, however, requires a promoter such as potassium in order to avoid carbon deposition at the practical levels of steam-to-carbon ratios of 3.5—5.0. Deposition of carbon from hydrocarbons cracking on the particles of the catalyst reduces the activity of the catalyst for the reforming and results in local uneven heating of the reformer tubes because the firing heat is not removed by the reforming reaction. 

Process condensate from reforming operations is commonly treated by steam stripping. More recentiy the stripper has been designed to operate at a... 

Primely and Secondary Reforming . The conversion of natural gas to synthesis gas in the reforming operation is represented by steam reforming ... 

Process condensate from reforming operations is commonly treated by steam stripping. The stripper is operated at a sufficiently high pressure to allow the overhead stripping steam to be used as part of the reformer steam requirement (71). Contaminants removed from the process condensate are reformed to extinction, so disposal to the environment is thereby avoided. This system not only reduces atmospheric emissions, but contributes to the overall efficiency of the process by recovering condensate suitable for boiler feedwater make-up because the process is a net water consumer. 

The octane number R + M jT) of such reformates is typically in the range of 88.9—94.5, depending on severity of the reforming operation. Toluene itself has a blending octane number of 103—106, which, as shown in Table 19, is exceeded only by oxygenated compounds such as methyl tert-huty ether, ethanol, and methanol. 

In another example Newby et al. [6] calculated a cycle with the reformer operating at comparable pressure and temperature but with a higher recycling rate of 1.7, leading to a conversion rate of a = 0.56 (this is closer to the conversion rate of Lloyd s steam/TCR cycle, a = 0.373, described in the last section). A thermal efficiency of 38.7% is claimed for this FG/TCR cycle, slightly greater than the simple CBT cycle efficiency of 35.7% but much less than the calculated efficiency for the steam/TCR cycle (48.7%) and a comparable STIG cycle (45.6%). 

Normally, catalytic reformers operate at approximately 500-525°C and 100-300 psig, and a liquid hourly space velocity range of 2-4 hr" Liquid hourly space velocity (LHSV) is an important operation parameter expressed as the volume of hydrocarbon feed per hour per unit volume of the catalyst. Operating at lower LHSV gives the feed more contact with the catalyst. 

Most of the benzene in the gasoline pool comes from the reformer unit (reformate). To reduce the reformate s benzene, one must modify the feedstock quality and/or operating conditions. Benzene s precursors in the reformer feed (C, and C ) can be prefractionated and sent to an isomerization unit. The reformer operating pressure can be reduced... 

The plasma reformer efficiency reached 12.3% and 26% in gasoline auto thermal and steam reforming regimes, respectively. The typical composition of the effluent gas from the reformer operating in steam reforming mode was (vol%) H2—28.7, CO—15, C02—3, and CH4—40. 

Hycar (1) A reforming process for making syngas from light hydrocarbons, differing from the standard process in using two reactors. The second reactor (a convective reformer), operated in parallel with the primary reformer, preheats the feedstock. Developed by Uhde. 

Continuous reforming operations, 25 166 Continuous salt mining, 22 806 Continuous saponification, 22 737—738, 741 in vinyl alcohol polymerization, 25 609-610... 

Cyclic peptides, self-assembly of, 24 59-60 Cyclic peroxides, 18 436, 447-448, 459 Cyclic poly(aliphatic disulfide)s, 23 712 Cyclic poly(disulfide)s, available information related to, 23 713 Cyclic polyethers, 12 658 chelating agents, 5 710 Cyclic reforming operations, 25 166 Cyclic sesquiterpenoids, biosynthetic routes to, 24 472 Cyclic siloxanes... 

Semi-gloss alkyd paint formulation, 18 6 It Semi-interpenetrating network (IPN) approaches, 10 436 Semi-IPN (interpenetrating polymer network) hydrogels, 13 733 Semikilled steels, 23 291 Semimoist pet foods, 10 849 Semipermanent cells, 14 228 Semiphorone, 14 583 Semiportable mri system, 23 860-861 Semiregenerative reforming operations, 25 166... 

In industry, large steam reformers generally produce between 20 000 and 100 000 Nm3/h of hydrogen. These reformers can be scaled down to 1000 Nm3/h. Their disadvantages are their large size and a high cost for materials, imposed by the conditions of pressure and temperature. Compact steam reformers have been developed for use with fuel cells. These reformers operate at a lower pressure and temperature (3 bar, 700 °C) the requirements for materials are thus less. For these units, energy conversion efficiency can reach 70%-80%. 

NOx reformer operating conditions —Condenser maximum temperature —Oxygen feed rate... 

Figure 1-14 shows a simplified layout for an SOFC-based APU. The air for reformer operation and cathode requirements is compressed in a single compressor and then split between the unit operations. The external water supply shown in figure 1-14 will most likely not be needed the anode recycle stream provides water. Unreacted anode tail gas is recuperated in a tail gas burner. Additional energy is available in a SOFC system from enthalpy recovery from tail gas effluent streams that are typically 400-600°C. Current thinking is that reformers for transportation fuel based SOFC APUs will be of the exothermic type (i.e. partial oxidation or autothermal reforming), as no viable steam reformers are available for such fuels. 

When the naphtha feed to a cat reformer has a naturally high content of these precursors, the yields of toluene are high. Other than this fortuitous circumstance, theres generally not too much attention paid to toluene in the reforming operation for several reasons ... 

Table 3. Vaporizer and Reformer Operating Conditions and Performance (Adapted from ref 88)...

The reformer was operated for over 554 h, which included 402 h of reforming operation and 152 h of hot standby. During hot standby, the catalyst was maintained in the reduced state by flowing 50 cm of hydrogen through the catalyst bed, which was kept at a minimum of 260 °C. The reactor was operated over a heater temperature range of 260—300 °C and up to 70 psia. A methanol and water mixture (S/C 1 1 molar) was fed at 1.5—3.5 mL/min. Table 5 summarizes the device performance. 

This endothermic reaction is driven by heating the reactor externally or by adding oxygen to the feed to provide the necessary energy by highly exothermic combustion reactions. A typical steam reformer operates at 15 to 30 atm and 850 to 900 C with a Ni/Al203 catalyst and a superficial contact time (based on the feed gases at STP,... 

Oil refineries (hydrogen produced in cracking and reforming operations ... 

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