Hydrogen consumption and

Lyondell and Sun Oil Co. are the main producers of benzene by disproportionation. Eiaa Oil Co. of Texas has developed the Eiaa T2BX process for toluene disproportionation usiag a proprietary catalyst. The new catalyst is claimed to reduce hydrogen consumption and is suitable for feeds containing small amounts of moisture (53). A commercial production unit was started up ia the fall of 1985. 

Consuming hydrogen is mainly a function of the number of benzene substituents. Dealkylation of polysubstituted benzene increases hydrogen consumption and gas production (methane). For example, dealkylating one mole xylene mixture produces two methane moles and one mole of benzene it consumes two moles of hydrogen. 

Table I compares the conditions and results of this operation to those for conventional SRC for Illinois 6 coal. At the short residence time, the coal conversion determined by pyridine solubility is 89% compared to 95% at conventional SRC conditions. The hydrogen consumption and production of light gases are reduced significantly at short residence time, while the SRC yield is increased.

The hydrogen consumption and enantioselectivities for the asymmetric hydrogenation of dimethyl itaconate with various substituted catalysts of the basic type [Rh(PROPRAPHOS)COD]BF4 are illustrated in Figure 10.13 [61]. The systems are especially suitable for kinetic measurements because of the rapid hydrogenation of COD in the precatalyst. There are, in practice, no disturbances due to the occurrence of induction periods. 

In an alternate version of the process ( 7), designated SRC-II, a portion of the coal solution is recycled as solvent in place of the distillate solvent of the SRC-I process. The filtration step is eliminated and, typically, the process operates at a higher pressure, higher temperature, and longer residence time than the SRC-I process. Hydrogen consumption and the conversion of dissolved coal is increased, and the primary product is a liquid rather than the solid product of the SRC-I process. The liquid product of the SRC-II process is the feedstock that is the subject of the work described in this chapter. 

This would result in an unreasonably high hydrogen consumption and operating cost. Therefore, a modification of the conventional SRC process is necessary to meet the proposed NSPS with minimum hydrogen requirements. 

The area under a TPR or TPO curve represents the total hydrogen consumption, and is commonly expressed in moles of H2 consumed per mole of metal atoms (H2/M). The ratios of almost 1.5 for rhodium in the right panel of Figure 2.4 indicate that rhodium was present as RI12O3. For iron, the H2/M ratios are significantly lower, indicating that this metal is only partially reduced. 

Hydrocarbonization processes are characterized by three primary independent variables - temperature, hydrogen pressure, and coal type - and five other, important independent variables -solid residence time, gas residence time, reactor configuration, coal pretreatment, and catalyst impregnation. Control of these variables permits control, over a wide range, of (1) the relative yields of liquid, gaseous, and solid products, (2) the quality of one or more of these products, (3) hydrogen consumption, and, ultimately (4) product cost. 

The available information leads one to believe that the maximum production of liquids with no net hydrogen consumption and the low-temperature catalytic hydrocarbonization/gasification are alternatives which appear to have great merit. The former of these, when applied to western coals, appears to be technically ready for commercial application and economically competitive with alternative coal liquefaction processes. Advantages of the flash hydropyrolysis processes over the Coalcon process are difficult to perceive. 

Alkynes are hydrogenated all the way to alkanes if the usual heterogeneous catalysts (Pd, Pt, Raney Ni) are used. If a suitable deactivated catalyst is used, however, it is possible to stop these reactions after monohydrogenation. The so-called Lindlar catalyst is a commonly used deactivated catalyst of this type (Figure 17.81). To prevent an overhydrogenation, it is still necessary to monitor the rate of hydrogen consumption and to interrupt the reaction after one equivalent of hydrogen gas has been absorbed even when the deactivated catalyst is used. The... 

Because we find that a linear relationship exists between temperature and hydrogen consumption on the one hand and between temperature and SRC conversion on the other, a linear relation should exist between hydrogen consumption and SRC conversion. Indeed, the plot of data in Figure 10 shows such a relationship. 

These caluclations of refinery hydrogen requirements are based on hydrogen consumption data summarized in Table 6 for the various processes that consume and produce hydrogen. These hydrogen consumption data allow for the theoretical hydrogen consumption and 20% excess above that required to maintain the desired hydrogen purity in the process. 

The advantages of simplicity and low cost more than outweigh the disadvantages of hydrogen consumption and production of additional inerts in the makeup gas to the synthesis loop. 

In addition, in order to prevent the deactivation of the catalyst caused by the deposited coke or coke precnrsor, the process needs to be operated at high hydrogen pressures and this leads to high hydrogen consumption and high constrnction cost of the reactor. 

These heavy gas oils were processed under conditions of 1300 psig, 3000 SCF Ha/bbl., 1 LHSV, and temperatures of 625°, 675°, and 725°F. In addition to sulfur and nitrogen removals, hydrogen consumption and aromatics saturation monitoring was attempted. 

The hydrogen for the hydrogen sulfide generator is supplied by a gas producer or reformer. The hydrogen sulfide generator provides the gas needed for the sulfur generation step (Reaction 3). In the overall Reaction 1, SO2 is removed from the power plant flue gas at the expense of hydrogen consumption and yields elemental sulfur as a useful by-product. 

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