An internal combustion engine 1 is provided, in an exhaust passage thereof with an electrochemical reactor including: an ion conductive solid electrolyte layer; an anode layer arranged on a surface of the solid electrolyte layer; and a cathode layer arranged on a surface of the solid electrolyte layer and able to hold NO.sub.X. The engine includes a current control device for controlling the current supplied to the electrochemical reactor so as to flow from the anode layer through the solid electrolyte layer to the cathode layer. The current control device is configured so as to supply current to the electrochemical reactor at least temporarily while that internal combustion engine is stopped.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

A process for altering the composition of a feed gas containing H.sub.2S equivalents is disclosed. The process comprises (a) contacting the feed gas with a solid adsorbent at a temperature of 250-500 C., to obtain a loaded adsorbent, (b) purging the loaded adsorbent with a purge gas comprising steam, thus producing a product stream which typically contains substantially equal levels of CO.sub.2 and H.sub.2S. The process further comprises a step (c) of regenerating the purged adsorbent by removal of water. The adsorbent comprises alumina and one or more alkali metals, such as potassium oxides, hydroxide or the like.

Proposed is a pretreatment desulfurization method for marine fuel oil. The method includes a step of preparing a pretreatment desulfurization agent including (a) at least one oxide selected from the group consisting of SiO2, Al2O3, Fe2O3, TiO2, MgO, MnO, CaO, Na2O, K2O, and P2O3, (b) at least one metal selected from the group consisting of Li, Cr, Co, Ni, Cu, Zn, Ga, Sr, Cd, and Pb, and (c) at least one liquid composition selected from the group consisting of sodium tetraborate (Na2B4O7.10H2O), sodium hydroxide (NaOH), sodium silicate (Na2SiO3). and hydrogen peroxide (H2O2). The method also includes a step of feeding the pretreatment desulfurization agent to a fuel supply line through which marine fuel oil is supplied to a marine engine at a certain ratio so that a fluid mixture containing the marine fuel oil and the pretreatment desulfurization agent is supplied to the marine engine, thereby adsorbing and removing sulfur oxides during combustion of the fluid mixture.

The present invention describes the process of preparing ceramic materials for absorption of acidic gases, mainly carbon dioxide, in exhaust systems and/or present indoors. Ceramic materials are formed by a mixture of alkali carbonate with alkaline earth metal oxide/hydroxide associated with a binding component, but non-limiting. The alkali carbonate comprises sodium, potassium carbonate, or a mixture of both. The alkaline earth metal oxide/hydroxide may be formed from magnesium oxide or magnesium hydroxide as well as calcium oxide and/or calcium hydroxide.

There is disclosed a microporous crystalline material comprising a crystal structure having building units of double-6-rings (d6r) and pore opening of 8-rings, wherein the material comprises a first metal chosen from alkali-earth group, rare-earth group, alkali group or mixtures thereof, and a second metal chosen from copper, iron or mixtures thereof, wherein the material has molar silica to alumina ratio (SAR) from 3 to 12, and is further steamed to enhance stability. Methods of making the crystalline material are also disclosed. There is also disclosed a method of selective catalytic reduction of nitrogen oxides in exhaust gas, comprising at least partially contacting the exhaust gases with an article comprising the disclosed microporous crystalline material.

It is an object to provide an exhaust gas purification catalyst for a lean burn engine having sufficient NOx purification performance. The exhaust gas purification catalyst for a lean burn engine according to the present invention has a catalyst component including noble metal and ceria supported on a three-dimensional structure. In the whole catalyst, the supported amount of ceria per 1 L of catalyst is 140 to 300 g/L, and in the whole catalyst, is 50 to 98% by mass with respect to the whole coated amount. Furthermore, it is characterized that 50% by mass or more of ceria is included in the same catalyst layer in which noble metal is included, and the amount of noble metal included in the catalyst layer is 0.1% by mass or more with respect to the amount of ceria included in the catalyst layer.

An object of the present disclosure is to provide an exhaust gas purification catalyst demonstrating superior storage of NOx contained in exhaust gas. The exhaust gas purification catalyst of the present disclosure has a substrate, a first catalyst layer containing a catalytic metal for NOx reduction and a NOx storage material and formed on the substrate, and a second catalyst layer containing a catalytic metal for NOx oxidation and formed on the first catalyst layer. In the exhaust gas purification catalyst of the present disclosure, the value obtained by dividing the volume of all large pores having a pore volume of 1000 m.sup.3 or more by the total volume of all medium pores of having a pore volume of 10 m.sup.3 to 1000 m.sup.3 in the second catalyst layer is 2.44 or less.

Provided is a honeycomb fired body in which the pressure loss in the initial state where PM has not accumulated is sufficiently low, the strength is sufficiently high, and the heat capacity is not small. The honeycomb fired body of the present invention is a honeycomb fired body including a plurality of cells in each of which one end is plugged and which serve as channels of exhaust gas, and porous cell partition walls that define the cells, wherein the honeycomb fired body is formed of SiC, the plurality of cells include peripheral cells located at an outermost peripheral region of the honeycomb fired body and inner cells located more inward than the peripheral cells, all the inner cells have the same cross-sectional shape that is a rectangle in a plane perpendicular to the longitudinal direction thereof, each peripheral cell is defined by the cell partition walls and an outer wall forming a periphery of the honeycomb fired body, the cell partition walls in contact with the outer wall each have a thick wall region where the wall thickness gradually increases toward the outer wall, the cross-sectional shape of the peripheral cells in a plane perpendicular to the longitudinal direction thereof is a shape formed by reducing the rectangular cross-sectional shape of the inner cells to obtain a reduced rectangle and chamfering or rounding two corners of the reduced rectangle, the cross-sectional area of each peripheral cell in a plane perpendicular to the longitudinal direction thereof is 60 to 80% of the cross-sectional area of each inner cell in a plane perpendicular to the longitudinal direction thereof, the cell partition walls include inter-peripheral-cell cell partition walls each located between the peripheral cells and inter-inner-cell cell partition walls each located between the inner cells, and the minimum thickness of the inter-peripheral-cell cell partition walls is greater than the thickness of the inter-inner-cell cell partition walls.