A method of detecting an open arc in a DC plasma arc furnace which is based on detecting a linear decrease in the log of the magnitude of the frequency spectrum of the voltage between the anode and cathode.

A device for preheating rod-like, metal workpieces, in particular aluminium rods, by means of a fluid flow heated by residual heat or waste heat of a combustion process occurring in a heating device for heating the workpieces. The device has a preheating chamber for receiving at least one workpiece, wherein, in order to transfer the heat from the fluid flow to a heat transfer medium flow in a fluid flow line between a fluid flow connection and the preheating chamber, a heat-exchanger unit is provided in such a way that the workpiece is preheated indirectly via the heat transfer medium flow heated in the heat-exchanger unit by the fluid flow.

A method for using waste heat from a cement producing plant, wherein heat of a process gas is used through a heat exchanger, which comprises a sequence of cyclones, for heating raw mix. A cement producing plant having at least one calcinator and at least one heat exchanger, which comprises a series of cyclones for heating raw mix. The process gas is removed at the outlet of the calcinator and/or at the gas-side outlet of the first cyclone in the heat exchanger in the direction of gas flow and, once the heat has been removed in a steam vessel, the cooled process gas is fed back into the second cyclone or third cyclone in the heat exchanger in the direction of gas flow. The heat taken from the process can be used for the further heating of unrecovered heat which can thereby be more efficiently converted into electrical energy.

The present invention provides a fluidized calciner which can perform sufficient calcination by reducing a rate of unburned fuel at an outlet of the fluidized calciner while preventing occlusion in a preheater. In the present invention, plural pulverized coal blowing lines (3), raw material chute (4) of cement raw material, and first to fourth air introduction pipes (5a to 5d) are connected to a bottom side wall of a tubular furnace body (2) whose upper end portion is closed by a top plate (2b); a fluidizing air blowing port (2a) adapted to blow in fluidizing air is disposed at a bottom of the furnace body (2); an exhaust gas duct (6) is connected to a top side wall of the furnace body located above the first and/or second air introduction pipes (5a, 5b) by being spaced away from the top plate (2b); and blowing ports (3a) of the pulverized coal blowing lines are disposed below suction ports of respective air introduction pipes (5a to 5d) but above the fluidizing air blowing port (2a), and at least one of the blowing ports (3a) is placed below the third or fourth air introduction pipe (5c or 5d).

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

A heat recovery device and an alignment film curing system. The heat recovery device can be provided outside a heating device, and it includes a first recovery unit including a first chamber and a first communicating pipe that is provided in the first chamber. The first chamber has a first gas inlet and first gas outlet, a first waste gas inlet and a first waste gas outlet, and the first communicating pipe is arranged in a winding way and connected between the first gas inlet and the first gas outlet in an enclosed way. The first gas inlet is connected to a gas supply pipe of the heating device, the first gas outlet is connected to an intake pipe of the heating device, the first waste gas inlet is connected to an exhaust pipe of the heating device, and the first waste gas outlet is configured to discharge waste gas.

A raw gas collection system for collecting raw gas from a plurality of aluminium smelting pots is equipped with a plurality of branch ducts, each of which is arranged to channel a respective branch flow of raw gas from an aluminium smelting pot to a collection duct, which is common to and shared by the branch ducts. Each of said branch ducts is, near an outlet thereof, equipped with a curved section for aligning the branch flow with a flow direction of raw gas already present in the common collection duct, and a constriction for accelerating the branch flow through the branch duct outlet into the common collection duct. Furthermore, each of said branch ducts is equipped with a heat exchanger for removing heat from the respective branch flow of raw gas. The combined flow resistance of the constriction and the heat exchanger reduces the need for adjusting the respective branch flows using dampers, thereby reducing the power required to transport the raw gas.

A kiln system is provided, including a drying section, a preheating section, a firing section, a soaking section, a cooling section, and a decarburization section arranged between the drying section and the preheating section. The decarburization section includes an ignition zone, a hot air combustion/pyrolysis zone, and a waste heat recovery pipeline. A heat source is introduced into the ignition zone so that the temperature of the ceramsite of the raw materials with heating values in the zone is 400° C. to 900° C. The hot air combustion/pyrolysis zone is configured for combusting or pyrolyzing carbon-containing materials and organic components in the raw materials with heating values in the ceramsite. The waste heat recovery pipeline is configured for discharging decarburization exhaust gas and recovering heat released after the raw materials with heating values in the ceramsite are combusted or pyrolyzed in the decarburization exhaust gas.

A heat energy recovery installation installed on a beam reheating furnace equipped with burners includes a turbine that generates electricity by implementing a Rankine cycle on an organic fluid coming from calories derived partly from the fluid used for cooling the tubular beams via a first intermediate circuit, and in part from flue gases from the burners by way of a second intermediate circuit.

An industrial kiln employs a tunnel kiln design. An upper portion of a central high-temperature firing region of a kiln body (1) has an arch structure, and is divided into a rising portion (4), a middle portion (5), and a descending portion (6). The rising portion (4), the middle portion (5), and the descending portion (6) are connected by means of curved surfaces with smooth transitions. A transporting mechanism (2) at a lower portion of the kiln body (1) is parallel to the upper portion. The present invention enables collection of excessive heat in a pre-heating portion and a cooling portion to transfer the same to a high-temperature firing portion, thus reducing a firing time and burning fuels of a high-temperature firing region, lowering a production cost, and protecting the environment by preventing exhaustion of a large amount of hot air.