31 research outputs found
Direct Catalytic Reduction of SO2 by CH4 over Fe-Mn Catalysts Prepared by Granulation of Ferromanganese Nodules
The chemical, textural, structural and strength properties of ferromanganese nodules and granulated Fe-Mn catalysts containing such nodules were studied. It was found that the granulated catalysts have a developed pore structure, which is close to that of the starting material, and surpass the starting material in strength parameters. The catalysts were tested in desulfurization by methane at a stoichiometric ratio SO2/CH4 = 2. The testing showed that Fe-Mn catalysts with the oxide or sulfide form of active components are active in desulfurization by methane and can selectively reduce SO2 with a conversion above 80%
Development of Catalytic Technologies for Purification of Gases from Hydrogen Sulfide Based on Direct Selective Catalytic Oxidation of H2S to Elemental Sulfur
In the Boreskov Institute of Catalysis in cooperation with specialists of All-Russian Institute of Hydrocarbons Raw Materials novel methods of purification of fossil fuels based on oxidation of hydrogen sulfide to elemental sulfur have been developed. In this paper the results of laboratory and pilot plant testing of the technologies are presented
Investigation of the Sorption Properties of Ore Materials for the Removal of Sulfur Dioxide from Exhaust Flue Gases of Power Plants
The prospects of using a natural material – ferromanganese nodules (FMN) from the Gulf of Finland – as the SO2 adsorbent are discussed. The starting material was studied as pellets and powder using X-ray fluorescence spectroscopy, XRD, BET, and mechanical strength analysis; dependences of physicochemical parameters of the material on heat treatment at 100-1000 ºC were found. FMN samples were tested in the process of SO2 sorption. The sorptive capacity of FMN samples for SO2 was found to increase with humidity of adsorbents; FMN samples with a humidity above 40% were shown to be promising for the removal of sulfur dioxide from gase
New Gas-Phase Catalytic Oxidative Processes for Desulfurization of Diesel Fuel
An effective gas-phase oxidative desulfurization (ODS) process was proposed. The process was studied in a laboratory reactor with a proprietary catalyst at 300-400 ºС and ambient pressure with model fuels represented by thiophene, dibenzothiophene(DBT) and 4,6-dimethyldibenzothiophene (DMDBT) dissolved in octane, isooctane or toluene. The reactivity of different sulfur containing molecules in ODS was shown to increase in the sequence: thiophene<DBT<DMDBT. The main sulfur containing product of oxidation of these compounds was SO2. During the gas-phase ODS both processes of sulfur species oxidation and processes of their adsorption were observed and studied. Based on the conducted studies, different ODS process designs comprising its integration with adsorption and regeneration processes and with conventional hydrodesulfurization (HDS) process were proposed. One scheme is based on alternating regimes of ODS and catalyst regeneration in two reactors: sulfur is removed from organic feedstock by oxidation and adsorption in one reactor while simultaneous regeneration of the catalyst that has accumulated sulfur compounds takes place in another reactor. Two other schemes are based on joint use of ODS and HDS. The conventional HDS process is most effective for removal of low-boiling sulfur containing compounds reactive with respect to hydrogen, while removal of refractory sulfur compounds, such as DMDBT is more easily achieved by gas phase ODS. Thus the combination of these processes is expected to be most efficient for deep desulfurization of diesel fuel
Determination of the density of Pb-Sn melts and segregation phenomena on their crystallization
Catalytic Synthesis of Thiophene from Dialkyl Disulfides and n -Butane
A modern industrial process for hydrocarbon feedstock cleaning of mercaptans is their oxidation to dialkyl disulfides with molecular oxygen in an alkaline medium in the presence of phthalocyanine catalysts [1 − 4]. The following main reactions relevant to this treatment for the removal of mercaptans occur in the material: 2 RSNa + 0.5 O 2 + H 2 O RSSR + 2 NaOH . As follows from this scheme, a byproduct of the process is a mixture of organic dialkyl disulfides RSSR, the so-called disulfide oil (DSO), a waste whose disposal from demercaptanization units is still an unresolved problem. To date, the disulfide oil has not found qualified application and is practically undisposable; meanwhile, its storage creates a safety hazard. Thus, the stock of DSO produced all over the world continuously grows. Therefore, the problem of the utilization of the disulfide oil via its processing into chemicals that are in demand is of great importance. One of the possible ways of coping with the problem is the conversion of DSO into thiophene, a compound used for the synthesis of a range of valuable drugs for human and veterinary medicine, as well as chemicals for agriculture (herbicides and pesticides) At present, according to In this work, we studied the feasibility of thiophene synthesis from organic dialkyl disulfides (disulfide oil) and n -butane using a modified magnesia-chromia-alumina catalyst. EXPERIMENTAL Feedstock components used in laboratory studies of thiophene synthesis were dimethyl disulfide containing a 99.57 wt % base substance; a mixture of organic dialkyl disulfides (disulfide oil) from the propanebutane demercaptanization unit (Orenburg gas processing plant) with dimethyl disulfide, methyl ethyl disulfide, and diethyl disulfide contents of 69.69, 24.54, and 3.15 wt %, respectively; and a grade B n -butane cut (TU (Technical Specifications) 0272-026-00151638-99) which contained 88.0 wt % n -butane (OAO Nizhnekamskneftekhim). A special catalytic system containing chromium and magnesium oxides as an active component and potassium and/or lanthanum oxides as a promoter of the general formula , where t lies in the range 5 wt %; x , y , and z are at most 3.2, 2, and 10 wt %, respectively; and the value of n ranges within 0-1, was designed for the thiophene Abstract -A promising new method for thiophene synthesis on the basis of dialkyl disulfides (byproduct of demercaptanization of hydrocarbon feedstocks) catalyzed by a modified magnesia-chromia-alumina catalyst was developed