WTA technology for drying of lignite coal Jul27

WTA technology for drying of lignite coal...

WTA technology for drying of lignite coal WTA (Wirbelschicht Trocknung Anlage) technology for drying of lignite coal has been developed by German company RWE Power AG. WTA is the German abbreviation which stands for fluidized-bed drying with internal waste heat utilization. RWE Power AG holds a good number of patents on this technology. The first steam-fluidized bed dryer was developed by RWE as the WTA-1 demonstration plant at Frechen near Cologne, Germany,  with a throughput capacity of 53 tons per hour of raw lignite coal having a grain size of 0 mm to 6 mm and an evaporative capacity of 25 tons per hour. During the 20,000 hours of test operation from 1993 to 1999, the WTA-1 demonstration plant along with the vapour compression system for drier heating (employed for the first time worldwide in lignite coal applications) has proved to work extremely well and reliably. Further theoretical work and an evaluation of the test operation of the WTA-1 plant revealed further potential for the technical and economic process optimization. Several alternatives of development were considered and it was revealed that a reduction of the grain size held most potential for further improvement. In 1999, RWE built a test plant called WTA-2 for the fine grained WTA process directly next to the WTA-1 plant in Frechen. This new plant had a design capacity which was increased in several optimization steps from originally 16.4 tons per hour of raw lignite coal throughput and 8 tons per hour evaporation capacity to a raw coal throughput of 28.7 tons per hour and a water evaporation capacity of 13.1 tons per hour during the total of 8,200 hours of operation of the plant by 2011. Based on the extensive experience from the operation of the WTA-2 plant with...

Steel ingots and their Casting during Steelmaking...

Steel ingots and their Casting during Steelmaking Ingot casting is a conventional casting process for liquid steel. Production of crude steel through the ingot casting route constitutes a very small percentage of global crude steel production. However, the method of casting of the liquid steel in ingot moulds is still fundamental for specific low-alloy steel grades and for special forging applications, where products of large dimension, high quality or small lot size are needed. Typical application for conventional ingot casting includes the power engineering industry (e.g. shafts for power generation plants, turbine blades), the oil and gas industry (conveying equipment, seamless tubes), the aerospace industry (shafts, turbines, engine parts), ship building (shafts for engines and drives), tool making and mechanical engineering (heavy forgings, cold, hot and high-speed steels, bearing, drive gears) as well as automotive engineering (shafts, axes). As the demand of heavy ingot increases nowadays, especially from the power engineering industry and ship industry, there is a tendency of producing extreme large ingots over 600 t and continuous cast strands with thickness over 450 mm and rounds with diameter up to 800 mm, which are mainly applied for pressure retaining components such as reaction vessels for nuclear power plant and rotating components like drive shafts of gas turbines and generator rotors. The moulds used for casting of ingots are made of cast iron. Cast iron is used for the production of the mould since the thermal coefficient of cast iron is lower than that of steel. Because of this property of cast iron, liquid steel on solidification contracts more than cast iron which makes detachment of ingot easier from the mould. Inner walls of the mould are coated by either tar or fine carbon. The coated material decomposes during solidification and this prevents sticking...

Business plan for the organization...

Business plan for the organization Business plan for an organization is the document which determines the organizational objectives, strategies and projected actions in order to promote its survival and development within a given time frame. Business plan also focuses on two key aspects namely (i) dealing with risks, and (ii) making profits. Business planning process requires deep investigation, careful evaluation of all factors, which might have an impact on the result, and study of possible results of the actions of the organization. In addition business plan determines management actions for expansion process, designs new ways of for management action and includes revision of all the operations of the organization. Business plan enables organizational management to demonstrate to stakeholders, including founders and investors, that there is potential for considerable growth of the organization in a large market. It also illustrates that the organization is capable of achieving significant market power with a sustainable and differentiated product or service offering. Business plan consists of a comprehensive, written description of the business of the organization. It is a detailed document describing the products or services of the organization, production techniques, markets and customers, marketing strategy, human resources, organization of important activities, requirements in respect of infrastructure and supplies, financing requirements, and sources and uses of funds. Business plan describes the past and present status of the organizational business, but its main purpose is to present the future of the organization. It is normally updated frequently and looks ahead for a period of three to five years normally, depending on the type of business and the kind of the organization. It is a crucial document needed for getting funding support from financial institutions and hence it is required to be complete, sincere, factual, well-structured and reader-friendly document. There...

Drying Technologies of Lignite Coals Jul20

Drying Technologies of Lignite Coals...

Drying Technologies of Lignite Coals Coals are generally ranked as anthracite, bituminous, sub-bituminous, and lignite, with anthracite being the oldest and lignite the youngest in the age. As coal ages, its moisture content decreases and heating value increases. The lignite coal is often being referred to as brown coal. It is considered to have the lowest rank, lowest carbon (C) content and highest moisture content. Moisture content in lignite coals can be even 60 % or more. Lignite coals are usually shallow buried facilitating its easy open mining. These coals besides high moisture content also have high volatile content and low calorific value (CV) with easy spontaneous ignition. High moisture content is the main restraint for the application of lignite coals. Moisture content of coal causes many difficulties during processing, storage, transport, grinding, and combustion. The high moisture content considerably reduces the CV and combustion efficiency of the coal. It also results into higher heat loss in the exhaust gas. In the combustion of lignite coals, the important part of the energy is consumed to evaporate the moisture inside the coal. The combustion of the high moisture content coal creates several problems such as the additional energy consumption for the moisture evaporation, the insufficient combustion and the additional exhaust discharge etc. Moisture content of the lignite coals can be classified into the following three types. Surface moisture – It is also known as external moisture. The moisture adheres to the surface of coal particulates or in the bigger capillary cavities. It is the moisture, which can be removed by the coal drying in air at ambient temperature (around 25 deg C). It depends on water conditions in deposit. Inherent moisture – It is a naturally combined part of the coal deposit. It is also...

Ferro-Chrome

Ferro-Chrome Ferro-chrome (Fe-Cr) is an alloy comprised of iron (Fe) and chromium (Cr).  Besides Cr and Fe, it also contains varying amounts of carbon (C) and other elements such as silicon (Si), sulphur (S), and phosphorus (P). It is used primarily in the production of stainless steel. The ratio in which the two metals (Fe and Cr) are combined can vary, with the proportion of Cr ranging between 50 % and 70 %. Fe-Cr is frequently classified by the ratio of Cr to C it contains. The vast majority of Fe-Cr produced globally is the ‘charge chrome’. It has a lower Cr to C ratio and is most commonly produced for use in stainless steel production. The charge chrome grade was introduced to differentiate it from the conventional high carbon Fe-Cr (HC Fe-Cr). The second largest produced Fe-Cr ferro-alloy is the HC Fe-Cr which has a higher content of Cr than charge chrome and is being produced from higher grade of the chromite ore. Other grades of Fe-Cr are ‘medium carbon Fe-Cr’ (MC Fe-Cr) and ‘low carbon Fe-C’ (LC Fe-Cr). MC Fe-Cr is also known as intermediate carbon Fe-Cr and can contain upto 4 % of carbon. LC Fe-Cr typically has the Cr content of 60 % minimum with C content ranging from 0.03 % to 0.15 %.  However C content in LC Fe-Cr can be upto 1 %. In international trade, Fe-Cr is classified primarily according to its C content. The common categories of Fe-Cr used in international trade are as follows. Charge chrome with a base of 52 % Cr. HC Fe-Cr with C content ranging from 6 % to 8 %, base of 60 % Cr, and a maximum of 1.5 % Si. HC Fe-Cr with C content ranging from 6...