Gas Cleaning Plants are used for cleaning the outlet gases of Mini Blast Furnace in the steel industries. These gases are hazardous in nature and contain high calorific value, hence cannot be let out in the atmosphere.
Liquid iron production process in the blast furnace (BF) generates gas at the furnace top which is an important by-product of the BF process. It contains certain calorific value. The top gas of the Blast Furnace is at the certain temperature and pressure exiting at the Blast Furnace top and usually contaminated with dust and water particles. This gas is also known as raw Blast Furnace gas or contaminated Blast Furnace gas. The composition and quantity of this top gas depends on the nature of the technological process in the blast furnace and the type and quality of the raw materials used for iron production in the blast furnace. In order to further use the contaminated Blast Furnace gas, it is necessary to clean it by using certain cleaning process systems which reduces outlet dust content of the solid particles and reduces the top pressure for further use in downstream process. Our Gas Cleaning Plant provides both the performance parameters i.e. reducing the dust content to less than 5 mg/Nm3 and killing the top pressure suitable for downstream process. The top gas contains carbon monoxide (CO) and is known as blast furnace gas after its cleaning. It is used as fuel gas for heating blast air in the hot blast stoves as well as supplemental fuel in the steel plant. For the BF gas to be used as fuel gas, it is necessary that the raw BF gas is cleaned with Gas Cleaning Plant and cooled to reduce gas volumes with reduction in moisture content.
Use of Gas cleaning plants for cleaning Blast Furnace gases results in substantial savings in delivery costs throughout the extensive distribution system of the steel plant.
The dust-laden blast furnace gases after dust catcher are cleaned in the Gas cleaning plant. The unit is of latest design consisting of two-stage High Energy ventury Scrubbing system. The first stage ventury provides pre-cleaning of BF gases. The second stage ventury provides final cleaning of the BF gases. The system is highly efficient, and yields cleaned BF Gas. Coarse dust particles are removed in the scrubber removing 90 – 95% of the dust from the gases. Water is supplied to the scrubber through recirculation (clean) water pumps from Clarifier plant. Dust laden water is discharged through water sealing system to the launder for treatment and recycling.
The precleaned gases leaving after first stage ventury passes into the second stage of gas cleaning plant comprising of a high energy ventury scrubber of adjustable flaps. In the venturi throat, the gas moves against the water spray for separation of fine dust particles. The venturi throat is equipped with mechanism to adjust the throat area, which allows optimum adaptation to the gas volume generated in the blast furnace. Differential pressure across the GCP controls second stage venturi throat opening automatically. The gas leaving the second stage venturi enters the Centrifugal separator where the finest water droplets are flung against the scrubber shell and run down into the sump, and gas gets free from water particles leaving the gas cleaning plant for distribution through pipeline network to various downstream applications. In the separator, we provide highly efficient mist eliminator specially designed to reduce the outlet moisture content to less than 5%.