In one embodiment, an acid gas removing apparatus includes an absorber configured to bring a first gas including an acid gas and a lean solution into contact to discharge a rich solution that is the lean solution having absorbed the acid gas, a regenerator configured to separate the acid gas from the rich solution discharged by the absorber to discharge the lean solution that is the rich solution separated from the acid gas, and a measuring instrument configured to measure a temperature of the rich or lean solution in the regenerator. Furthermore, an acid gas removal control apparatus that controls the acid gas removing apparatus includes a receiver configured to receive the measured temperature, and a controller configured to control resupply of a resupplied solution to the rich or lean solution or removal of an acid component from the rich or lean solution, based on the received temperature.

A system may include a NO.sub.x sensor and a controller. The controller may be configured to interpret a value of a first parameter indicative of an amount of NO.sub.x measured by the NO.sub.x sensor and interpret a value of a second parameter for a NO.sub.x value from a look-up table. The controller may be further configured to determine a correction factor based on the value of the first parameter and the value of the second parameter and generate a dosing command based, at least in part, on the determined correction factor. In some implementations, the NO.sub.x value from the look-up table may be based on one or more operating conditions of an engine. In some implementations, the controller may be further configured to update a NO.sub.x value of the look-up table based on the determined correction factor.

Methods for the use of zinc ammonium carbonate as a scavenger of sulfur-containing species encountered in oilfield operations are provided. In one embodiment, the methods include introducing a sulfide scavenging additive including zinc ammonium carbonate into at least a portion of a conduit through which a potential sulfur-containing fluid is flowing.

An aftertreatment module is disclosed. The aftertreatment module may include a housing. The aftertreatment module may include a mounting plate within the housing that forms an inlet chamber and an outlet chamber. The aftertreatment module may include an inlet for exhaust gas from a combustion engine to flow into to the inlet chamber. The aftertreatment module may include an outlet through a top plate of the housing. The inlet and the outlet may be located on opposite sides of the housing and at opposite ends of the housing from each other. The aftertreatment module may include a set of catalysts mounted to the mounting plate. The aftertreatment module may include a diffuser plate within the inlet chamber that forms a lower portion of the inlet chamber and an upper portion of the inlet chamber. The diffuser plate may diffuse the exhaust gas through the lower portion.

The present invention describes a fluid which is suitable for the decontamination of heat engines which can carry out, at the same time, both the catalytic reduction of oxides of nitrogen (NOx) contained in exhaust gases and assist in the regeneration of the particulate filter (PF). The invention also describes several embodiments of said fluid consisting of producing an oil-in-water type emulsion.

A catalyst for treating an exhaust gas comprising SO.sub.2, NO.sub.x and elemental mercury in the presence of a nitrogenous reductant comprises a composition containing oxides of: (i) Molybdenum (Mo) and/or Tungsten (W); (ii) Vanadium (V); (iii) Titanium (Ti), and (iv) an MFI zeolite, wherein the composition comprises, based on the total weight of the composition: (i) 1 to 6 wt % of MoO.sub.3 and/or 1 to 10 wt % WO.sub.3; and (ii) 0.1 to 3 wt % V.sub.2O.sub.5, and (iii) 48.5 to 94.5 wt % TiO.sub.2; and (iv) 35 to 50 wt % MFI zeolite.

There is provided a method for recycling 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 method for recycling a denitration catalyst includes a step of spraying an aqueous solution with a pH of 7 or more onto a used denitration catalyst while the denitration catalyst is set in a denitration device to remove a surface of the denitration catalyst. 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. The denitration catalyst after recycling is used for denitration at 200 C. or lower.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

Methods for the use of zinc ammonium carbonate as a scavenger of sulfur-containing species encountered in oilfield operations are provided. In one embodiment, the methods include introducing a sulfide scavenging additive including zinc ammonium carbonate into at least a portion of a conduit through which a potential sulfur-containing fluid is flowing.

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 is obtained by coating a substrate with a catalyst component. The catalyst component contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more. The denitration catalyst is used for denitration at 200 C. or lower.