Abstract:
A blast furnace where coke Is combusted with oxygen, Instead of air, and where a top gas comprising CO, CO 2 , H 2 , and without excess nitrogen is withdrawn from the upper part of the blast furnace, cleaned of dust, the H 2 /CO volume ratio adjusted to between 1.5 to 4.0 in a water shift reactor, water and CO 2 are removed (increasing its reduction potential), heated to a temperature above 850°C, and fed back to the blast furnace above where iron starts melting (thereby Increasing the amount of metallic iron reaching the dead-man zone and decreasing the amount of coke used for reduction). Also carbon deposit problems caused by heating the CO-containing recycled gas are minimized by on-line cleaning of the heater tubes with steam without significantly affecting the reduction potential of the recycled reducing gas.
Abstract:
A blast furnace installation comprises a blast furnace (10), a gas cleaning unit and lateral top gas extraction tubes connected between an upper topcone (14) of the blast furnace (10) and the gas cleaning unit. According to an aspect of the present invention, the blast furnace installation further comprises a central gas uptake conduit (22) with an uptake opening (26) arranged in the vicinity of a vertical axis of the blast furnace in an upper portion of the blast furnace (10) for extracting gas from an axial region of the blast furnace (10); and an auxiliary gas cleaning unit (24) connected to the central gas uptake conduit (22) for cleaning gas extracted via the central gas uptake conduit (22).
Abstract:
The present invention provides a method for decreasing the temperature of blast-furnace gas temperature peaks which is characterized in that the pressure of the blast-furnace gas is being measured continuously, and injection of water into the blast-furnace gas is triggered off when a threshold value for the pressure is exceeded. The injection of water is carried out in at least one member of the group consisting of the three members blast furnace's furnace throat, off-takes through which blast furnace gas is diverted from the blast furnace to a -first dedusting device, pipes through which the blast furnace gas is diverted from the first dedusting device to a second dedusting device or from the second dedusting device to a further dedusting device. It also provides a devices-system for performing the method comprising means for triggering off (7) the means for injection of water (4) based on a signal of the means for measuring the pressure (6).
Abstract:
The present invention describes a method for treating a Zn contaminated material in a blast furnace installation comprising a blast furnace charged with a traditional burden of iron ore and coke, a gas cleaning unit, and lateral top gas extraction uptakes connected between an upper top cone of said blast furnace and said gas cleaning unit, said method comprising the following steps: a. Providing Zn contaminated material, b. Charging said Zn contaminated material in a central area of a raw material feeding zone of a blast furnace in addition to the traditional burden of iron ore and coke, c. Reducing the Zn contaminated material in the blast furnace so as to obtain a Zn enriched gas, d. Extracting a Zn enriched gas from the blast furnace, e. Treating said extracted Zn enriched gas in the gas cleaning unit.
Abstract:
The invention concerns a cupola for producing melt iron, comprising a vessel (2) for heating the materials to be smelted by burning combustion products inside the vessel (2), means (21) for loading the vessel with materials to be smelted, means (21) for supplying agents of combustion, means (10) for collecting fuel gases, means (12) for extracting fuel gases, means (7) for supplying oxidizing gas into the vessel and means (3) for evacuating the melt iron. The invention is characterised in that the oxidant-supplying means are formed by at least a suction nozzle (7); the extraction means (12) are adapted to set up relative to atmospheric pressure and relative to the fuel gas collecting means, a sufficient vacuum inside the vessel (2) for sucking up the oxidizing gas through the nozzle (7).
Abstract:
A process for treating particulate material containing heavy metal generated during a manufacturing process is disclosed. The process includes providing particulate material containing heavy metal within an enclosed area and mixing an additive of calcium silicate forming material with the particulate material in the enclosed area to create an additive-particulate material. The additive-particulate material can be passed into a waste collection device located downstream of the enclosed area. The calcium silicate forming material can be provided as particles with a particle size of minus 50 to plus 325 mesh. An additional aspect of the invention is an additive for use in such a process for treating metallic oxide impregnated dust, which has a particle size of plus 325 mesh and consists essentially of calcium silicate forming material.
Abstract:
The essential operation of the process consists in closed circuit spraying (2) of water on the dry dusts in the gases. The dust cleared gases are conducted into a washing equipment (4) which removes the harmful gases. The washing liquid (7) is neutralised, eventually mixed with ashes and put back into circulation.