Hydrogen sulfide reformate

Sulfur hexafluoride Ethylene dichloride Hydrogen sulfide Reformer hydrogen... 

The reaction for hydrogen production via the hydrogen sulfide reforming of methane is as follows [21] ... 

Depending on the H2S/CH4 ratio, hydrogen sulfide reforming occurs at a temperature higher than 850°C. At these temperatures, the elemental sulfur produced is in the vapor phase and cannot cause deactivation of metal sulfide-based catalysts. However, the formation of solid carbon can be harmful for the catalysts. To avoid coking effect, the molar ratio of H2S/CH4 must be greater than 4. As indicated by thermodynamic analyses [21], a higher H2S/CH4 ratio can reduce carbon formation to zero at lower temperatures. 

The conversion products, other than gas and hydrogen sulfide (H2S), are essentially a gasoline fraction that, after pretreatment, will be converted by catalytic reforming an average quality distillate fraction to be sent to the gas oil pool and an atmospheric residue or vacuum distillate and vacuum residue whose properties and impurity levels (S, N, Conr. 

The first step in the production of synthesis gas is to treat natural gas to remove hydrogen sulfide. The purified gas is then mixed with steam and introduced to the first reactor (primary reformer). The reactor is constructed from vertical stainless steel tubes lined in a refractory furnace. The steam to natural gas ratio varies from 4-5 depending on natural gas composition (natural gas may contain ethane and heavier hydrocarbons) and the pressure used. 

Surprisingly, Britain s hard-fought reforms cost factory owners little. The summer after an industrialist spent 300 to install the towers required by the Alkali Act, nearby fruit trees that had not blossomed in years bloomed and roses grew. Unfortunately, reformers could not convince the government to ban the release of hydrogen sulfide too new technology could control the release of hydrochloric acid gas, but not hydrogen sulfide gas. 

In a continuous reformer, some particulate and dust matter can be generated as the catalyst moves from reactor to reactor and is subject to attrition. However, due to catalyst design little attrition occurs, and the only outlet to the atmosphere is the regeneration vent, which is most often scrubbed with a caustic to prevent emission of hydrochloric acid (this also removes particulate matter). Emissions of carbon monoxide and hydrogen sulfide may occur during regeneration of catalyst. 

The hydrogen sulfide and ammonia can be removed by amine extraction and acid washes respectively. Hydrotreating also removes metals from the feed that would otherwise poison the reforming and cracking catalysts. 

Hydrogen sulfide and mercaptans Sour crudes formed by decomposition of sulfur compounds during distillation, cracking, reforming, and hydroprocessing... 

In most reported studies, model sulfur compounds are added to the liquid fuel to study their effect on deactivation. Sulfur in the fuel usually reacts to form hydrogen sulfide in the reformer, which is then removed downstream. In one such study, Palm et al. describe the ATR of mixtures of n-Ci3-Ci9... 

Similar results were achieved over a Rh/alumina monolith catalyst " using catalytic POX for the reforming of a simulated JP-8 military feed containing 500 ppm of sulfur (as benzothiophene or dibenzothiophene). Stable performance for over 500 h with complete conversion of the hydrocarbons to syngas at 1,050°C, 0.5 s contact time, and LHSV of about 0.5 h was reported. At this high temperature, carbon formation was not reported and the sulfur exited as hydrogen sulfide. 

Water Acetylene, Air, Argon, Carbon Dioxide, Chlorine, Cracked Gas, Ethylene, Helium, Hydrogen, Hydrogen Chloride, Hydrogen Sulfide, Natural Gas, Nitrogen, Oxygen, Reformer Hydrogen, Sulfur Hexafluoride... 

In the steam-reforming process (Fig. 1), the hydrocarbon feedstock is first desulfurized by heating to 370°C in the presence of a metallic oxide catalyst that converts the organosulfur compounds to hydrogen sulfide. Elemental sulfur can also be removed with activated carbon absorption. A caustic soda scrubber removes the hydrogen sulfide by salt formation in the basic aqueous solution. 

The presence of sulfur in the feed is also a problem for conventional steam reforming. If the catalyst is not sulfur tolerant, the sulfur will deactivate it (Rostrup-Nielsen, 1984). If the catalyst is "sulfur tolerant", i.e., able to tolerate small amounts of feed sulfur, the sulfur leaves the process as hydrogen sulfide and is likely to cause unacceptable problems downstream. Furthermore many major natural gas resources are "sour," i.e., contain a large percentage of hydrogen sulfide. 

Bench scale experiments using diesel fuel have shown that for typical fuel sulfur concentrations there is no detectable sulfur in the reformate to at least the sub-ppm level. In the bench scale experiments, when sulfur was added to diesel fuel at a concentration of 2000 ppm by weight only 5 ppm hydrogen sulfide was detected in the reformate. In pilot scale experiments using diesel fuel, the sulfur concentration in the reformate stream was around 15 ppm. If the sulfur was not captured by the pilot-scale reactor, the sulfur concentration in the reformate stream would have been 37 ppm. 

At the same time a decrease of the thiophene conversion can be related with blockage of some active species by hydrogen sulfide released during reaction and thiophene adsorbed too. The activity restoration when adsorbed components of reaction mixture are flowed by H2 or Ar is related to the reformation of the active species (Figure 2). The H2 S desorbtion (revealed in desorbed products along with butenes) leads to increase of the HDS activity and intensity of the Mos signals. The same result was also observed on the preliminarily reduced sample. 

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