A carbon fiber production method includes a carbon fiber production step including an oxidation step and a carbonization step; and an exhaust gas processing step including a heat exchange step; an external air mixing step; and a mixed external air supplying step in which the mixed external air is supplied to at least one step that uses heated gas in the steps in the carbon fiber production step; and among the exhaust gases, a high heating value exhaust gas having a heating value of 250 kcal/Nm.sup.3 or higher is supplied to an inlet side of an exhaust gas combustion apparatus and a low heating value exhaust gas having a heating value lower than 150 kcal/Nm.sup.3 is supplied to an outlet side of the exhaust gas combustion apparatus, respectively.

Disclosed is an induced-draft gas-fired furnace that includes: an electronic furnace controller, a burner assembly, a gas valve, and an inducer motor, wherein the controller: accelerates the inducer motor at a first pre-ignition rate to a first pre-ignition speed; controls the gas valve to supply gas to the burner assembly to obtain a first pre-ignition ratio of fuel to air, operates an igniter to attempt to ignite the first fuel mixture, determines whether fuel has ignited in the burner assembly, wherein when fuel having the first pre-ignition ratio of fuel to air remains unignited after a plurality of ignition attempts, the controller: decelerates the inducer motor to a second pre-ignition rate to obtain a second pre-ignition speed and a second fuel mixture comprising a second pre-ignition ratio of fuel to air, and determines whether the second fuel mixture has ignited in the burner assembly.

Systems and methods for reducing NO.sub.x and CO emissions in a natural draft heater are disclosed. For example, the disclosure provides embodiments of systems and methods for controlling a draft value within a heater shell to deliver an amount of excess air to a burner to thereby maintain at least one of NOx emissions not exceeding 0.025 lb/MMBtu (HHV) and CO emissions not exceeding 0.01 lb/MMBtu (HHV) in a natural draft heater.

A method is provided for thermally converting non-radioactive combustible wastes to a substantially non-hazardous, non-leachable, sintered particulate carbon-less ash by-product in a kiln having a plurality of reaction zones. The kiln including first and second ends and a body provided between the first and second ends that defines a cavity having a refractory lining that provides resistance to heat conduction. A processor and flow rate controllers are provided that control a flow rate through the body of waste that enters at the first end of the kiln and the flow rate of oxidant gas that enters at the second end of the kiln, the second end being opposite to the first end. The body may be positioned substantially horizontal and may include a length-to-diameter ratio and a resistance to heat conduction that provides a temperature gradient within the cavity to forms separate reaction zones during operation.

Device for controlling combustion process in power station furnace system, having burners (1) in combustion chamber. The combustion air is supplied via annular gap (3) surrounding burners which may influence quantity of combustion air flowing through the annular gap (3). Quantity of fuel supplied to burner (1) is recorded, and quantity of combustion air flowing through annular gap (3) is determined, for which two formed sensor rods (11, 12), arranged in the annular gap (3.1), successively and in parallel, preferably transversely to the longitudinal axis (4) of the annular gap and in the flow direction (7) of the combustion air flow, the sensor rods (11, 12) allow part of the combustion air to flow past the first sensor rod (12) in the flow direction (7) of the combustion air flow and also flows past the second sensor rod (11) in the flow direction (7) of the combustion air flow.

A horticultural smudging system and method for improving the growth and/or production of plants. Combustible material is burnt within a thermal container, and the resulting flue gas containing negative ions and carbon dioxide is propelled onto one or more plants. The smudging system and method may use one or more sensors to detect oxygen, air pressure, and flue gas levels within the thermal container to adjust air intake and the release of flue gas.

A small heating system is provided for the combustion of solid fuels, having: a gasification zone for generating combustion gas and a combustion zone for combusting combustion gas; a first blower for supplying primary air into the gasification zone; and a second blower for supplying secondary air into the combustion zone , wherein the first blower can be regulated depending on the desired output of the small heating system and/or the second blower can be regulated depending on a desired oxygen content in the exhaust air from the combustion zone.

Boiler systems and associated control systems, methods for operating same, are described herein. In one example embodiment, a boiler system includes a furnace, an exhaust passage, an air passage, a FGR passage, a flue gas valve that is adjustable by way of a first actuator, a NO.sub.X gas sensor, an oxygen gas sensor, and an additional valve that is adjustable by way of a second actuator. Further, the boiler system includes at least one processing device coupled to the NO.sub.X gas sensor, the oxygen gas sensor, the first actuator and the second actuator. The at least one processing device is configured to generate control signals that are provided to the first actuator and second actuator, and also configured to generate correction factors by way of a calibration process and to utilize one or more of the correction factors in determining one or more of the control signals.

A blocking prevention device for a gasification melting system combusts and melts an object to be treated into a slag in a melting furnace after the object to be treated is converted into pyrolysis gas in a gasification furnace, the blocking prevention device including: a slag adhesion prevention device having a slag adhesion prevention capability for preventing adhesion of the slag at an opening part that may be blocked due to the adhesion of the slag; an imaging device that images the opening part; and a control device including a calculation unit that calculates a change rate of an opening area of the opening part using a plurality of images with different capturing times or a video, captured by the imaging device, and a prevention device control unit that changes the slag adhesion prevention capabilities of a plurality of the slag adhesion prevention devices in accordance with the change rate.

Various embodiments include a combustion apparatus. An example apparatus includes: a burner; a side duct; and a feed duct. The side duct comprises an inlet, an outlet, and a mass flow sensor between the inlet and the outlet of the side duct. The mass flow sensor is configured to detect a signal corresponding to an amount of flow of a fluid through the side duct. The side duct comprises a first portion and a second portion. The first portion of the side duct comprises the mass flow sensor. The first portion of the side duct is arranged within the feed duct.