There is provided a catalyst that exhibits a high denitration efficiency at a relatively low temperature and does not cause oxidation of SO.sub.2 in a selective catalytic reduction reaction that uses ammonia as a reducing agent. A denitration catalyst contains 3.3 wt % or more of vanadium oxide in terms of vanadium pentoxide and has a BET specific surface area of 10 m.sup.2/g or more.

A combustion system for ships operated at low cost is provided. A combustion system 1 for ships includes an internal combustion engine 20 that burns fuel, an exhaust line L2 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the internal combustion engine 20, an exhaust heat recovery device 40 that is disposed in the exhaust line L2 and that recovers exhaust heat from the exhaust gas discharged from the internal combustion engine 20, and a denitration device 50 that is disposed in the exhaust line L2 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 50 is disposed downstream from the exhaust heat recovery device 40 in the exhaust line L2. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.

Herein disclosed is a new electrochemical approach to catalyst capture and recycling that overcomes conventional industrial recovery methods using functionalized redox-polymer electrodes. This technology provides a redox electro-separation system comprising polyvinylferrocene that was able to capture platinum group metal based catalysts directly from products and transfer to fresh reactants achieving 99.5% recovery without disturbing catalyst activity. Several reactions were tested along with various solvent-electrolyte matrices, showing >99% recovery efficiencies for platinum species as low as 1.6 ppm.

A process involves sequentially treating a plurality of lipid feedstocks comprising a set of lipid feedstocks each having a chloride content of at least about 2 ppm with a metal oxide catalyst on an oxide support under first treating conditions to produce respective treated streams of the set of lipid feedstocks having a chloride content less than 1 ppm until a given one of the respective treated streams has a chloride content greater than 1 ppm and the metal oxide catalyst is converted to a spent metal oxide catalyst, converting the spent metal oxide catalyst to a rejuvenated metal oxide catalyst, and treating one or more additional lipid feedstocks each having a chloride content of at least about 2 ppm with the rejuvenated metal oxide catalyst under second treating conditions to produce one or more respective treated streams each having a chloride content less than 1 ppm.

A used denitration catalyst is regenerated by means of a method comprising bringing the used denitration catalyst comprising titanium oxide as an essential ingredient into contact with a suspension of particles comprising manganese oxide, subjecting the resulting product to a liquid draining, and subjecting the liquid-drained product to a drying process, additionally, further comprising impregnating a solution comprising a compound containing at least one element selected from the group consisting of vanadium, molybdenum and tungsten into the denitration catalyst after the drying process, and subjecting the impregnated product to a drying treatment.

The invention refers to a process for rejuvenating a hydrotreating catalyst comprising a group VIB hydrogenation metal and/or a group VIII hydrogenation metal, which comprises the steps of: (a) regenerating the catalyst by contacting said catalyst with an oxygen containing gas at a temperature from about 300 C. to 550 C., (b) impregnating the regenerated carbon-reduced catalyst with an impregnation solution which comprises a mixture of water and a combination of MoO.sub.3 and H.sub.3PO.sub.4, (c) aging the impregnated catalyst and (d) drying the aged catalyst. The invention also refers to the rejuvenated catalyst obtained and its use for hydrotreating hydrocarbon feedstocks.

Articles comprising a catalyst film comprising VOx, MoO.sub.3 or WO.sub.3, and TiO.sub.2 deposited on a substrate are disclosed. The articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases. Methods for producing such articles deposit a catalyst film on the substrate to form a coated substrate, which is then calcined. When used in an SCR process, the coated articles have enhanced activity for NOx conversion, reduced activity for SOx conversion, or both. Light-weight, coated articles having high catalyst loads can be fabricated at the same or reduced dimensions when compared with laminated articles, and increased kNOx/kSOx ratios are available even from coated articles having relatively thin catalyst films. The articles should have particular value for power plant operations, where coal and high-sulfur fuels are commonly used and controlling sulfur trioxide generation is critical.

The following invention relates to methods for reprocessing SCR catalysts. In a first embodiment, the invention relates to a method for reprocessing SCR catalysts, wherein an oxygen-containing compound of titanium and tungsten or molybdenum is removed from the catalyst and is then reacted with a vanadium compound. In a second embodiment, the invention relates to a method for removing titanium oxide and vanadium, molybdenum, and tungsten compounds from SCR catalysts and to a method for reusing these compounds in such catalysts.

The invention refers to a process for rejuvenating a hydrotreating catalyst comprising a group VIB hydrogenation metal and/or a group VIII hydrogenation metal, which comprises the steps of: (a) regenerating the catalyst by contacting said catalyst with an oxygen containing gas at a temperature from about 300 C. to 550 C., (b) impregnating the regenerated carbon-reduced catalyst with an impregnation solution which comprises a mixture of water and a combination of MoO.sub.3 and H.sub.3PO.sub.4, (c) aging the impregnated catalyst and (d) drying the aged catalyst. The invention also refers to the rejuvenated catalyst obtained and its use for hydro-treating hydrocarbon feedstocks.

The following invention relates to methods for reprocessing SCR catalysts. In a first embodiment, the invention relates to a method for reprocessing SCR catalysts, wherein an oxygen-containing compound of titanium and tungsten or molybdenum is removed from the catalyst and is then reacted with a vanadium compound. In a second embodiment, the invention relates to a method for removing titanium oxide and vanadium, molybdenum, and tungsten compounds from SCR catalysts and to a method for reusing these compounds in such catalysts.