ULCORED Process Mar18

ULCORED Process

ULCORED Process ULCORED is a direct reduction (DR) process, which produces DRI (direct reduced iron) in a shaft furnace, either from natural gas (NG) or from reducing gas obtained by gasification of coal. Off-gas from the shaft is recycled into the process after carbon di-oxide (CO2) has been captured, which leaves the DR plant in a concentrated stream and goes to storage. The DRI step produces a solid product which is then melted using an electric arc furnace (EAF). The process was designed mainly in 2006 by a team led by LKAB, Voest-alpine and MEFOS. The objective of the ULCORED process was to reduce the NG consumption needed to produce DRI. It was achieved by replacing traditional reforming technology with partial oxidation (POx) of NG. Combined with CCS device, ULCORED can reduce 70 % CO2 emission compared with the average in the BF route. The concept of the ULCORED process involves separating CO2 out of the process gas. It is characterized by an effort to adopt gas based DR process to a minimized emission of green- house gases (GHG), using CO2 capture and storage (CCS) technology and at the same time to a minimized use of energy. The process is designed in a way which allows for the extraction and storage of CO2. The process is therefore also dependent on CCS with a similar in-process capture. The process is based on the utilization of a shifter to convert the carbon monoxide (CO) gas from the shaft to hydrogen (H2) together with a CO2 removal unit. This opens up a new innovative evolution of the process concept. The main features of the ULCORED DR process include (i) use of oxygen (O2) instead of air resulting into an off gas of nearly 100 % CO2 which...

Top Gas Recycling Blast Furnace Process Mar09

Top Gas Recycling Blast Furnace Process...

Top Gas Recycling Blast Furnace Process In the area of production of hot metal (HM) by blast furnace (BF), the most promising technology to significantly reduce the CO2 (carbon di-oxide) emission is recycling of CO (carbon mono oxide) and H2 (hydrogen) from the gas leaving the BF top. CO and H2 content of the top BF gas has a potential to act as reducing gas elements, and hence their recirculation to the BF is considered as an effective alternative to improve the BF performance, enhance the utilization of C (carbon) and H2, and reduce the emission of CO2. This ‘top gas recycling’ (TGR) technology is mainly based on lowering the usage of fossil C (coke and coal) with the re-usage of the reducing agents (CO and H2), after the removal of the CO2 from the top BF gas. This leads to lower the energy requirements. Because of the advantages of high productivity, high PCI (pulverized coal injection) rate, low fuel rate, and low CO2 emission etc., the TGR-BF process is considered to be one of the promising ironmaking processes in future. In TGR-BF, oxygen (O2) is blown into the BF instead of hot air to eliminate nitrogen (N2) in the top BF gas. Part of the top BF gas containing CO and H2 is utilized again as the reducing agent in the BF. CO2 from the BF top gas is captured and then stored. Several recycling processes have been suggested, evaluated or practically applied for different objectives. These processes are distinguished by (i) with or without CO2 removal, (ii) with or without preheating, and (iii) the position of injection. The concept of the TGR-BF (Fig 1) involves many technologies which include (i) injection of reducing top BF gas components CO and H2 in the...

Non Cryogenic processes of Air Separation Jul25

Non Cryogenic processes of Air Separation...

Non Cryogenic processes of Air Separation   Dry air contains by volume 78.08 % of nitrogen, 20.95 % of oxygen, and 0.93 % of argon along with traces of a number of other gases (Fig 1). Atmospheric air can contain varying amount of water vapor (depending upon humidity) and other gases produced by natural processes and human activities. Fig 1 Composition of air Non cryogenic air separation processes are near ambient temperature separation processes and are used for the production of nitrogen or oxygen as gases. These processes are cost effective choices when demand of gases are relatively small and when very high purity of the gases is not required. Non cryogenic plants are compact and produce gaseous nitrogen which is typically 95.5 % to 99.5 % oxygen free or gaseous oxygen which is 90 % to 95.5 % pure. Non cryogenic plants are less energy efficient than cryogenic plants (for comparable product purity) but at the same time cost less to build. The physical size of the plant can be reduced as required purity is reduced, and the power required to operate the unit is reduced as well.  Non cryogenic plants are relatively quick and easy to start up and can be brought on line in less than half an hour. This is useful when product is not needed full time. Like cryogenic plants, non cryogenic air separation processes also start with compression of air. Unlike cryogenic plants which use the difference between the boiling points of nitrogen and oxygen to separate and purify these products, non cryogenic air separation plants use physical property differences such as molecular structure, size and mass to produce nitrogen and oxygen. Non cryogenic processes are based on either selective adsorption or permutation through membranes. The most common technologies...