In an oxyfuel combustion boiler system, nitrogen gas separated by an air separation unit (ASU) is supplied as carrier gas to a pulverizer for drying and pulverization of fuel. A fluid mixture of the nitrogen gas from the pulverizer with pulverized fuel is supplied to a powder separation device where the pulverized fuel is separated. The separated pulverized fuel is mixed with the primary recirculated flue gas and supplied to a burner.

A method to determine a reduction rate of a recovery boiler using optical information from a chemical smelt sample. A processor is used to read a digital frame at least part of which represents the chemical smelt sample of the recovery boiler. An area of interest is determined from the digital frame read comprising at least part of the area in the digital frame representing the chemical smelt sample. Of the pixel values of the area of interest, one or more spectral characteristic values correlating with the change of reduction rate are determined. The reduction rate of the recovery boiler is determined using a reduction rate function of one or more of the determined spectral characteristic values weighted at predetermined weights.

In a suction fan type combustion apparatus, when an air supply/exhaust path of a combustion and heating unit is clogged, a combustion fan has a degraded fan current for the same fan rotation speed. Furthermore, the suction fan type configuration has the combustion and heating unit's internal pressure reduced as the combustion fan rotates faster. A combustion burner supplies fuel gas with a pressure applied thereto, which is regulated by a gas proportional valve. A degree of opening of the gas proportional valve is corrected in a direction allowing the pressure to be reduced, in accordance with a rate of degradation of a fan current relative to a reference current following a reference current characteristic. This control for correction is done with the fan current degradation rate smoothed (or low-pass filtered) in a time base direction.

Method for operating a gas burner appliance (10), by providing during an actual burner-on-phase of the gas burner appliance (10) in request to an actual nominal heat demand a flow of a gas/air mixture (M) to a burner chamber (11), the gas/air mixture (M) having a defined mixing ratio of gas (G) and air (A), wherein said gas/air mixture (M) is provided by a mixing device (25) mixing an air flow with a gas flow, wherein the air flow or the flow of the gas/air mixture is provided by a fan (14) in such a way that a fan speed of the fan (14) depends on the actual nominal heat demand, wherein the fan speed range of the fan (14) defines a modulation range of the gas burner appliance (10), wherein said defined mixing ratio of gas (G) and air (A) of the gas/air mixture (M) is controlled by a controller (26) using as input a signal provided by a sensor (13) and providing as output a control variable for an electric or electronic gas flow modulator (18) in order to keep the mixing ratio of gas (G) and air (A) at the defined mixing ratio over the modulation range of the gas burner appliance (10). If the actual nominal heat demand of the gas burner appliance (10) is no longer present the following steps are automatically executed in order to set-up the gas burner appliance (10) for an upcoming burner start: Decrease during the actual burner-on-phase the fan speed of the fan (14) to a defined fan speed while keeping the mixing ratio of gas (G) and air (A) of the gas/air mixture (M) at the de-fined mixing ratio thereby decreasing the opening position of the gas flow modulator (18). Keep the gas flow modulator (18) at said decreased opening position and terminate the actual burner-on-phase of the gas burner appliance (10).

An example includes a combustion device comprising: a burner; a feed duct; an actuator adjusting a feed of fluid through the feed duct; and a control apparatus programmed to adjust the actuator. The actuator, upon receipt a request signal, checks for a stored rate of change in an associated memory and, if the stored rate of change is present, sends a response signal to the control apparatus. The control apparatus determines a rate of change from the response signal, and generates a first automation signal as a function of the stored rate of change. The first automation signal causes the actuator to change a mechanical variable of the actuator so the mechanical variable changes no faster than the stored rate of change.

A modulating gas valve assembly includes a modulating gas valve to variably control a flow of gas through the gas valve assembly and a control circuit. The control circuit includes a valve memory storing a calibration table for the modulating gas valve, and a controller communicatively coupled to the peripheral component. The calibration table includes a plurality of control settings for the modulating gas valve, each control setting being associated with a different gas flow rate. The controller is programmed to receive a command to open the gas valve, and to control the gas valve to a target control setting in the calibration table adjusted in accordance with a valve offset.

A premixing device which includes a premixing flow path including a first flow path and a second flow path, and a first fuel gas outlet and a second fuel gas outlet includes: a first blade section which is provided in the first flow path, and with which the first fuel gas outlet is provided; a protruding wall section which is provided on the first blade section; and a flapper which oscillates at a position downstream in the air flow direction than the first blade portion of the first flow path. When the flapper is in an open state below a specified opening degree, the flow of air from the first flow path to the first fuel gas outlet is capable of being suppressed by the protruding wall section.

A premixing device which includes a premixing flow path including a first flow path and a second flow path, and a first fuel gas outlet and a second fuel gas outlet includes: a first blade section which is provided in the first flow path, and with which the first fuel gas outlet is provided; a protruding wall section which is provided on the first blade section; and a flapper which oscillates at a position downstream in the air flow direction than the first blade portion of the first flow path. When the flapper is in an open state below a specified opening degree, the flow of air from the first flow path to the first fuel gas outlet is capable of being suppressed by the protruding wall section.

Described herein are two-stage catalytic heating systems and methods of operating thereof. A system comprises a first-stage catalytic reactor and a second-stage catalytic reactor, configured to operate in sequence and at different operating conditions, For example, the first-stage catalytic reactor is supplied with fuel and oxidant at fuel-rich conditions. The first-stage catalytic reactor generates syngas. The syngas is flown into the second-stage catalytic reactor together with some additional oxidant. The second-stage catalytic reactor operates at fuel-lean conditions and generates exhaust. Splitting the overall fuel oxidation process between the two catalytic reactors allows operating these reactors away from the stoichiometric fuel-oxidant ratio and avoiding excessive temperatures in these reactors. As a result, fewer pollutants are generated during the operation of two-stage catalytic heating systems. For example, the temperatures are maintained below 1.000 C. at all oxidation stages.

The invention relates to a method for the thermal disposal of pollutants in industrial gases, wherein, in order to generate a flame for burning the pollutants, a fuel gas and oxygen are fed into a combustion chamber (19) of a burner (1), where they are then ignited, wherein a diluent gas is fed in in order to reduce the calorific value of the gas mixture relative to the fuel gas, while the throughput of the diluent gas is regulated as a function of the composition of the industrial gas in order to adapt the gas mixture consisting of diluent gas and fuel gas. The invention also relates to a burner (1) for generating a flame (2) in a combustion chamber (19) for burning pollutants in an industrial gas, and to a waste-gas treatment device having at least one burner (1) arranged in a combustion chamber (19).