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 disclosure provides a collective exhaust system capable of safely detecting a closing failure of a check valve of the collective exhaust system. The collective exhaust system includes: multiple combustion devices including blowing parts and exhaust pipes; a collective exhaust duct to which the exhaust pipes of the multiple combustion devices are respectively connected; and check valves respectively provided between the exhaust pipes and the collective exhaust duct. The collective exhaust system is configured to detect a closing failure of the check valves by performing, in a state where one of the blowing parts of the multiple combustion devices is stopped and all the other blowing parts are driven with a predetermined blower capacity, a backflow determination from the collective exhaust duct to the combustion device with the stopped blowing part, and by performing the backflow determination for the multiple combustion devices.

A fuel control device includes a combustion temperature estimation value calculation unit that calculates a temperature estimation value when a mixture of fuel and inflow air is burned using an atmospheric condition, an opening degree command value of a valve that controls the amount of air that is mixed with the fuel and burned, and an output prediction value calculated on the basis of a fuel control signal command value used for calculation of a total fuel flow rate flowing through a plurality of fuel supply systems, a fuel distribution command value calculation unit that calculates a fuel distribution command value indicating a distribution of fuel output from the fuel supply systems based on the temperature estimation value, and outputs the fuel distribution command value, and a valve opening degree calculation unit that calculates each valve opening degree of a fuel flow rate control valve of the fuel supply systems.

A gas turbine engine includes: a combustor that combust the fuel and having an exit, a combustor exit temperature (T40) is the average temperature of flow and a combustor exit pressure (P40) is the total pressure there; a turbine including a rotor having a leading edge and a trailing edge, and wherein a turbine rotor entry temperature (T41) is an average temperature of flow at the leading edge and a turbine rotor entry pressure (P41) is the total pressure there; and a compressor having an exit, wherein a compressor exit temperature (T30) is the average temperature of flow at the exit from the compressor and a compressor exit pressure (P30) is the total pressure there (all at cruise conditions). A method of determining at least one fuel characteristic includes changing a fuel supplied to the engine; and determining a change in a relationship between T30 or P30, T40 and T41, or of P40 and P41, respectively.

A method for determining an estimate of the specific gravity of a fuel for a gas turbine engine is disclosed. The gas turbine engine includes a fuel control valve and one or more fuel injectors. The method includes determining a first estimate of the specific gravity based on an orifice flow model of the fuel control valve. The method also includes determining a second estimate of the specific gravity based on a combined orifice flow model of the one or more fuel injectors. The method further includes recursively filtering the first estimate and the second estimate to determine a third estimate of the specific gravity.

A module which measures the flow rate of fuel, having an inlet portion, an outlet portion and a primary conduit for transporting the fuel extending between said inlet and outlet portions for transporting a first flow of fuel; the module further has a secondary conduit for transporting fuel, adjacent to the primary conduit and extending between a first section and a second section of the primary conduit for transporting a second flow of fuel between the first and the second section; the module additionally has a measurement sensor of the flow rate of fuel introduced into the secondary conduit and a Venturi constriction device arranged in the primary conduit in proximity to or at the second section. Other aspects are described and claimed.

A hot water supply device includes: a combustion part including a first burner part for which a flame sensor is disposed and a second burner part having a different number of burners from the first burner part such that one or both of the burner parts perform combustion, the flame sensor being configured to detect combustion state information of a flame generated by burners; a combustion control part configured to monitor a combustion mode of the combustion part set in accordance with a hot water supply request and change a second combustion mode in which the first burner part does not perform combustion, to a first combustion mode in which at least the first burner part performs combustion, when the second combustion mode is continuing; and a combustion adjustment control part configured to execute a combustion adjustment process of the combustion part.

A fuel control device includes a combustion temperature estimation value calculation unit that calculates a temperature estimation value when a mixture of fuel and inflow air is burned using an atmospheric condition, an opening degree command value of a valve that controls the amount of air that is mixed with the fuel and burned, and an output prediction value calculated on the basis of a fuel control signal command value used for calculation of a total fuel flow rate flowing through a plurality of fuel supply systems, a fuel distribution command value calculation unit that calculates a fuel distribution command value indicating a distribution of fuel output from the fuel supply systems based on the temperature estimation value, and outputs the fuel distribution command value, and a valve opening degree calculation unit that calculates each valve opening degree of a fuel flow rate control valve of the fuel supply systems.

A combustor of a gas turbine engine includes a combustion chamber, pilot fuel supply unit configured to supply solely auxiliary fuel to a flame holding region in the combustion chamber, first auxiliary fuel amount adjustment unit configured to adjust an amount of the auxiliary fuel supplied from the pilot fuel supply unit, main fuel supply unit configured to supply unburned gas and the auxiliary fuel to an unburned gas combustion region in the combustion chamber continuous with the flame holding region, and second auxiliary fuel amount adjustment unit configured to adjust an amount of the auxiliary fuel, in which the first auxiliary fuel amount adjustment unit is configured to adjust the amount of the auxiliary fuel supplied from the pilot fuel supply unit to an amount for flame holding in the flame holding region throughout an operation of the gas turbine engine.

The objective of the present invention is to provide a combustion device capable of informing an amount of used gas, in which an air of gas temperature is reflected, to a user and a method of measuring the amount of used gas. To this end, the combustion device includes: a burner configured to burn gas; a blower configured to supply air for combustion to the burner; gas valves configured to supply gas for combustion to the burner; a gas temperature sensor configured to measure a temperature of gas supplied to the burner or the blower; and a control unit configured to control the number of revolutions of the blower, calculate a first amount of used gas for a present operating heat quantity burned according to a signal input by a user, and compensate the calculated first amount of used gas with a measured gas temperature measured by the gas temperature sensor to calculate a second amount of used gas.