Methane saving

A methane gas stream taken off the demethanizer process, and still at 350 psig, is compressed via byproduct energy from the turboexpanders and raised to 410 psig. The gas is then introduced into a 15,000 hp compressor and raised to 850 psig for delivery back to the El Paso Natural Gas Company. The 60 psig boost by each turboexpander represents a 15% reduction in required horsepower. This amounts to considerable energy saved and is yet another reason why the turboexpander is useful in a cryogenic process of this type. 

The methane warms to 10°C. It then passes through the booster compressors on the expansion turbine shaft, increasing in pressure from 325 psi to 375 psi before being introduced into other gas compressors tliat boost the pressure back up to 600 psi. This is the pressure needed for reintroduction of the natural gas back into the TransCanada pipeline. This 50 psi boost, which makes use of available energy from the expansion turbines, provides a significant savings in electrical power. 

Kreye C, Dittert K, Zheng X, Zhang X, Lin S, Tao H, Sattelmacher B. Fluxes of methane and nitrous oxide in water-saving rice production in north China. Nutr. Cycl. Agroecosyst. 2007 77 293-304. 

Reduction of carbon dioxide takes place at various metal electrodes. The main products are formic acid in aqueous solutions and oxalate, CO, and formic acid in nonaqueous solutions. An indium electrode is the most potential saving for C02 reduction. Due to the difference in optimum conditions between those for C02 reduction to formic acid and those for formic acid reduction to further reduced products, direct reduction of C02 in aqueous solutions without a catalyst to highly reduced products seems to be difficult at metal electrodes. However, catalytic effects of metal electrodes themselves have recently become more clear for example, on Cu, methane was detected, while on Ag and Au, CO was produced effectively in aqueous solutions. Furthermore, at a Mo electrode, methanol was obtained. The power efficiency is, however, still low at any electrode. 

Fig. 9.4. Pa (e) and (e) as a function of the binding energy. The simulations treated 216 water molecules, utilizing the SPC/E water model, and the Lennard-Jones parameters for methane were from [63]. The number density for both the systems is fixed at 0.03333 A 3, and T = 298 K established by velocity rescaling. These calculations used the NAMD program (www.ks.uiuc.edu/namd). After equilibration, the production run comprised 200 ps in the case of the pure water simulation and 500 ps in the case of the methane-water system. Configurations were saved every 0.5 ps for analysis...

A VaporSep system was installed at a polyethylene plant to recover 290 lb of ethylene per hour (Ib/hr) from a gas stream consisting of 18% hydrogen, 22% nitrogen, 30% methane, and 30% ethylene. The capital costs for the system were 200,000. Based on an ethylene value of 300 per ton, the plant would save 370,000 per year using the VaporSep system to purify and recycle the ethylene (D205549, p. 5). 

It is of interest to assess the process potential of methanol production by a direct partial oxidation of methane. This way the steam reformer and the shift reactor can be saved, and the catalytic methanol reactor can be replaced by a noncatalytic partial oxidation reactor. It is estimated that direct partial oxidation is competitive if a conversion of methane of at least 5.5% can be obtained with a methanol selectivity of at least 80%. 

Experiments, both in the field and laboratory, are very expensive. Models of methane production from hydrate can save substantial expense of time, effort, and capital. This section of Chapter 7 gives guidelines from the models for hydrate dissociation. 

Progressing from each of the above levels to the next saves 2-3 orders of magnitude in financial and time expense. So, for example, if one wished to perform a sensitivity study of methane production rate response to reservoir permeability or hydrate saturation, it is many orders of magnitude easier to do so via a model, than via a field test. 

The metallurgy industry requires about 12 reactors for direct iron recovery on the basis of MHR-T with steam methane reforming. Therefore, not less than 150 MHR-T shall be deployed in Russian energy-consuming industries in a medium-term perspective, till 2040-2050 whereby saving over 80 bln.m3 of natural gas. MHR-T-based complexes will increase competitiveness of energy-consuming industries on the world market despite the decision on transition to world prices of natural gas supply to the Russian consumers since 2011. 

Steam-methane reforming is considered an efficient way to get hydrogen from a hydrogen compound. This process has been used by the oil refinery and chemical industries for many years. Currently, there is a plentiful supply of natural gas in the United States and Canada (although that may not be true in the future). This also means a plentiful supply of methane. The pipelines needed to deliver the natural gas to processing plants are already in place. This saves time and money because many new delivery structures do not have to be built. 

Key features are the high reforming pressure (up to 41 bar) to save compression energy, use of Uhde s proprietary reformer design [1084] with rigid connection of the reformer tubes to the outlet header, also well proven in many installations for hydrogen and methanol service. Steam to carbon ratio is around 3 and methane slip from the secondary reformer is about 0.6 mol % (dry basis). The temperature of the mixed feed was raised to 580 °C and that of the process air to 600 °C. Shift conversion and methanation have a standard configuration, and for C02 removal BASF s aMDEA process is preferred, with the possibility of other process options, too. Synthesis is performed at about 180 bar in Uhde s proprietary converter concept with two catalyst beds in the first pressure vessel and the third catalyst bed in the second vessel. 

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