A. N. Zagoruiko

The process for catalytic incineration of waste gas on IC-12-S102 platinum glass fiber catalyst

The process for catalytic afterburning of volatile organic compounds (VOCs) in waste industrial gases was developed on the basis of a new platinum glass fiber catalyst (GFC) IC-12-S102 with low platinum content (∼0.02 wt %). The catalyst was shown to be more effective than the known industrial afterburning catalysts. The way of glass fiber catalyst loading to a reactor in the form of vertical spiral cartridges, structured with wire mesh of bulk weaving is described. The successful application of the IC-12-S102 catalyst was confirmed by its operation at OAO Nizhnekamskneftekhim in the process of waste gases afterburning in an industrial reactor with cleaned gases capacity up to 15000 m3/h. During the reactor operation in harsh conditions (low oxygen content, high content of water vapor), the degree of gas cleaning was 99.5–99.9% and the residual VOC content in the purified gases was no higher than 10–15 mg/m3. For more than 15 months of catalyst operation, the degree of gas purification was not reduced; thus, overall lifetime of the IC-12-S102 catalyst may be substantially longer than the life of well-known industrial afterburning catalysts.

Catalytic processes and catalysts for production of elemental sulfur from sulfur-containing gases

The modern technologies for production of elemental sulfur are considered. It is demonstrated that along with the further wide application of the conventional Claus process with conventional alumina catalyst in the observable future some new trends which may significantly influence the technological picture of recovered sulfur manufacturing may be formulated: active development of Claus tail gas cleanup processes with the stress on replacement of subdewpoint Sulfreen-type processes by processes of hydrogen sulfide selective oxidation by oxygen; development of novel highly-efficient technologies for hydrogen sulfide decomposition to sulfur and hydrogen; application of new catalysts forms, first of all — at microfiber supports for Claus and H2S oxidation processes; wider application of titania and vanadia catalysts at the newly constructed Claus units; development of technologies and catalysts for direct purification of H2S-containing gases and for catalytic reduction of SO2 for sulfur recovery from smelter gases. All these prospective routes are actively developed by Russian science and some of them are completely based on domestic developments in this area.

Vanadium oxide catalysts on structured microfiber supports for the selective oxidation of hydrogen sulfide

Vanadium(V) oxide catalysts for the selective oxidation of hydrogen sulfide to sulfur on a nonporous glass-fiber support with a surface layer of a porous secondary support (SiO2) are studied. The catalysts are obtained by means of pulsed surface thermosynthesis. Such catalysts are shown to have high activity and acceptable selectivity in the industrially important region of temperatures below 200°C. A glass-fiber catalyst containing vanadium oxide (10.3 wt % of vanadium) in particular ensures the complete conversion of H2S at a temperature of 175°C and a reaction mixture hourly space velocity (RMHSV) of 1 cm3/(gcat s) with a sulfur yield of 67%; this is at least 1.35 times higher than for the traditional iron oxide catalyst. Using a structured glass-fiber woven support effectively minimizes diffusion resistance and greatly simplifies the scaleup of processes based on such catalysts. Such catalysts can be used for the cleansing of tail gases from Claus units and in other processes based on the selective oxidation of H2S.

Structured woven glass-fiber IC-12-S111 catalyst for the deep oxidation of organic compounds

A platinum woven fiberglass supported IC-12-S111 catalyst whose preparation is based on pulsed surface thermosynthesis is developed. The IC-12-S111 catalyst contains small amounts of platinum (0.05–0.10 wt %), and cheap and commercially available types of fiberglass cloths are used in its production. The production technology is characterized by a small number of process stages and no wastes or platinum losses. The developed catalyst is superior to known platinum and oxide catalysts in its activity in the deep oxidation reactions of hydrocarbons, and exhibits high thermal and operational stability. IC-12-S111 based catalytic cartridges with regularly structured channels are characterized by low hydraulic resistance and minimize deposits of solid particles in a catalyst bed during operation in contaminated flows. The cartridges can be used to create beds of any size and configuration. The developed catalyst can be used for the afterburning of hydrocarbons and organic compounds in flue gases, the flameless oxidation of flare gases, and the catalytic combustion of hydrocarbon fuels in local power supply systems.

Characterization of vanadia catalysts on structured micro-fibrous glass supports for selective oxidation of hydrogen sulfide

Abstract This work is focused on the characterization of a novel vanadium pentoxide catalysts on a glass-fiber support. The catalyst support consists of a non-porous glass-fiber fabric covered with an additional external surface layer of porous secondary support of SiO2. The vanadia active component is synthesized from vanadyl oxalate precursor by means of an impulse surface thermo-synthesis method. Such catalysts demonstrate high activity and appropriate selectivity in the reaction of H2S oxidation by oxygen into sulfur in the practically important temperature range below 200°C. According to the characterization data, the freshly prepared vanadia catalyst partially consists of mostly the amorphous and badly ordered vanadia with some part of the wellcrystallized V2O5 phase. Under the reaction conditions the main part of vanadia in the catalyst remains in the amorphous V2O5 form, while the less part becomes reduces into of VO2 and other vanadium oxides (such as VO, V2O3 V3O7 and V4O9). Most probably, the crystallized V2O5 in course of reaction is responsible for the deep oxidation of hydrogen sulphide into SO2, while the lower vanadium oxides promote the selective H2S oxidation into elemental sulfur.

Modeling of a multidispersed adsorption-catalytic system for removal of organics from exhaust gas

A new approach to enhancing the efficiency of adsorption-catalytic removal of volatile organic compounds from exhaust gas is considered. This approach employs a structured fixed bed consisting of large pellets of a catalytic adsorbent and a microfibrous catalyst. Numerical modeling has demonstrated that, during the high-temperature oxidative regeneration of the catalytic adsorbent, the microfibrous catalyst is heated much more rapidly than the large pellets of the catalytic adsorbent owing to its substantially larger outer specific surface area. This makes it possible to efficiently oxidize the unoxidized volatile organic compounds that desorb from the surface of the catalytic adsorbent, thereby minimizing the desorption loss and markedly increasing the gas cleaning efficiency.

Glass fiber supports modified by layers of silica and carbon nanofibers

Abstract The new multi-layered composite was manufactured by deposition of the carbon nanofibers (CNF) at the surface of the glass-fiber fabric, which is pre-modified by application of additional external layers of NiO and porous silica. Carbonization of synthesized catalytic template was performed at 450 °C in propanebutane media at ambient pressure. CNF was deposited in amount of ~130% of initial template mass or 65 g per g of nickel, the specific surface area of the material is ~100 m2/g. The synthesized material has high mechanical strength, high hydrophobicity and strong bonding between CNF and glass-fiber support. The synthesis method is technologically simple, inexpensive and easily scalable. It is possible to manufacture such material in various solid shapes, using the flexibility of the primary glass-fiber support; in particular, it may be used for production of the mechanically self-sustainable catalytic cartridges with required shape and internal geometry using no additional structuring elements.

A microfiber catalyst with lemniscate structural elements

A new type of catalyst based on microfiber supports with microfibers twined into looped threads (lemniscate) that in turn form a structured flexible stable and geometrically regular bulk bed permeable to a reaction flow and not requiring any additional structurial elements is described. Deep toluene oxidation experiments show that the proposed platinum lemniscate glass-fiber catalyst (LGFC) considerably surpasses (by 8–10 times and more) familiar geometric types of catalysts, microfiber and otherwise, in both the specific observed activity per unit active component mass and the ratio between the observed activity and the specific hydraulic resistance. The reason for its superiority is a uniquely high efficiency of mass transfer in the external diffusion region of reactions. Among the promising fields of application for the proposed systems are fast gasphase catalytic reactions, liquid-phase catalytic reactions, and complicated reaction processes, in which the selectivity and the yield of target products are sensitive to diffusion inhibition.