A method of producing an oxide of manganese including reacting, in a first aqueous solution, a manganese salt and an alkali agent to form manganese hydroxide; separating the manganese hydroxide from the first solution; mixing the manganese hydroxide into an aqueous medium to form a manganese hydroxide suspension; mixing the manganese hydroxide suspension with alkali metal hydroxide to form a second aqueous solution; and oxidizing the manganese hydroxide in the second aqueous solution to form an oxide of manganese. The dried oxide of manganese includes birnessite, a maximum of 20% hausmannite, and a maximum of 10% feitknechtite, may further include a maximum of 400 ppm of anions, may have a specific surface area of at least 25 m.sup.2/g, and may have an average oxidation state of greater than 3.5.

A system used to recycle exhaust gas during olefin polymer production, comprising: a compression cooling mechanism (101); a hydrocarbon membrane separation mechanism (102) and a hydrogen membrane separation mechanism (103), both connected to a first outlet (202) of the compression cooling mechanism; and a deep cooling mechanism (104) connected to a first outlet (208) of the hydrogen membrane separation mechanism. A method used to recycle exhaust gas during olefin polymer production, comprising a compression cooling step, a hydrocarbon membrane separation step, a hydrogen membrane separation step and a deep cooling step.

A slope ?.sup.t1.sub.HC in a linear area of sensor output characteristics for a mixed atmosphere of CO and THC and a slope ?.sup.t1.sub.NH in the linear area of the sensor output characteristics for NH.sub.3 are specified in advance at a time when a time t1 has elapsed since a start of use of an engine. In performing calibration of an NH.sub.3 sensor when a time t2 (greater than the time t1) has elapsed, a slope ?.sup.t2.sub.HC in the linear area of the sensor output characteristics for the mixed atmosphere is specified, a value ?.sup.t2.sub.NH is calculated from an equation ?.sup.t2.sub.NH=?.sup.t2.sub.HC/(?.sup.t1.sub.HC/?.sup.t1.sub.NH), and the calculated value ?.sup.t2.sub.NH is determined as a new slope in the linear area of the sensor output characteristics for an NH.sub.3 gas.

An apparatus/system for generating a high-purity nitrogen gas using a fuel cell includes; a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen, and a fuel gas; a dehumidification mechanism that reduces moisture or water vapor content in an exhaust gas that is extracted from the fuel cell and has a lower oxygen concentration than air; and a filtering mechanism which includes a filter using fibers having different degrees of permeation for nitrogen and oxygen and converts the exhaust gas having a reduced moisture or water vapor content into a gas having an increased nitrogen concentration. The filter recovery ratio is higher when an oxygen concentration of a gas to be filtered is lower. The dehumidification mechanism is a pump unit including a water seal pump to provide an adiabatic expansion chamber in which the exhaust gas extracted from the fuel cell expands adiabatically.

An apparatus/system for generating a high-purity nitrogen gas using a fuel cell includes; a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen, and a fuel gas; a dehumidification mechanism that reduces moisture or water vapor content in an exhaust gas that is extracted from the fuel cell and has a lower oxygen concentration than air; and a filtering mechanism which includes a filter using fibers having different degrees of permeation for nitrogen and oxygen and converts the exhaust gas having a reduced moisture or water vapor content into a gas having an increased nitrogen concentration. The filter recovery ratio is higher when an oxygen concentration of a gas to be filtered is lower. The dehumidification mechanism is a pump unit including a water seal pump to provide an adiabatic expansion chamber in which the exhaust gas extracted from the fuel cell expands adiabatically.

Provided is an apparatus/system for generating a nitrogen-enriched gas reliably and stably using a fuel cell. The nitrogen gas generation apparatus/system comprises: a fuel cell configured to operate by taking in air or a gas containing nitrogen and oxygen, and a fuel gas; and a catalyst combustion mechanism configured to cause an exhaust gas that is extracted from the fuel cell and has a lower oxygen concentration than air to react with the fuel gas on a combustion catalyst, and convert the exhaust gas having a lower oxygen concentration than air into a nitrogen-enriched gas having an increased nitrogen concentration.

Methods are provided for the production of nitrogen, hydrogen, and carbon dioxide from an exhaust gas. Exhaust gas from combustion in a fuel rich (or reducing) atmosphere is primarily composed of CO.sub.2, CO, N.sub.2, H.sub.2O, and H.sub.2. CO may be converted to CO.sub.2 and H.sub.2 via the water gas shift reaction. Carbon dioxide may then be effectively separated from nitrogen and hydrogen to produce a carbon dioxide stream and a nitrogen/hydrogen stream. The nitrogen/hydrogen stream may then be effectively separated to produce a high purity nitrogen stream and a high purity hydrogen stream. The process may be done in any order, such as separating the nitrogen first or the carbon dioxide first.

Disclosed herein a technique for producing a gas mixture for controlling an oxygen concentration in the interior of a container while reducing the overall weight of the apparatus. For this purpose, a gas mixture supply device is provided for a container refrigeration apparatus. The gas mixture supply device is provided with adsorption columns. If one of the first and second adsorption columns is supplied with air, the adsorption columns are pressurized, and nitrogen in the air is adsorbed onto an adsorbent. If air is sucked from the other of the first and second adsorption columns, the adsorption columns are depressurized, and nitrogen adsorbed onto the adsorbent is desorbed. A gas mixture including the nitrogen desorbed from the adsorbent is supplied to the interior of a container.

Disclosed herein are new processes for adsorbing oxygen using adsorbent compositions comprising RHO zeolites kinetically selective for oxygen. The RHO zeolites can be used in pressure swing adsorption processes for separating oxygen from oxygen containing streams, such as for, but not limited to, purifying a crude argon feed stream or separating oxygen from an air feed stream.

Described herein is a method for detecting steady state ammonia slip for a motor vehicle having an internal combustion engine and an emissions control system. The emissions control system includes a selective catalytic reduction (SCR) device, a NOx sensor, and a controller. The controller executes a method for ammonia slip detection that includes determining if the SCR device is at steady state, comparing a NOx measurement from the NOx sensor with a predicted NOx value. If the NOx measurement exceeds the predicted NOx value by a threshold, perturbing a reductant injection, the perturbation having a selected magnitude and a selected duration. The method also includes measuring a NOx value resulting from the perturbation and computing a gradient thereof relative to the measured NOx, and ascertaining if a gradient of the NOx resulting from the perturbation exceeds a threshold and identifying a reductant slip condition if so.