Lünen Power Plant.

Transcription

1 Lünen Power Plant

2 Power and heat for the future Energy for the railways and residents As fifth biggest electricity producer in Germany, with ultramodern power plants in and outside Germany and a variety of services, STEAG GmbH safeguards the energy supply of the future reliably, efficiently, and with low environmental impact. STEAG blazes the trail for the energy sources biomass, biogas, mine gas, geothermics, wind and solar thermics. The engineers of STEAG Energy Services GmbH develop, build and operate power plants all over the world and are experts for the modernization of existing plants and for made-tomeasure energy supply which goes easy on the climate and at the same time is economical. Power plants at home and abroad STEAG operates eleven power plants at ten locations in Germany with an installed capacity of about 7,00 MW; nine of these plants use hard coal as primary energy source. At two sites, each of which integrates an industrial power plant, refinery by-products also are used to produce steam, compressed air and electricity. Most of the electricity from hard coal is supplied to industrial and public utilities. The customers include RWE, EnBW and Deutsche Bahn, the German Railways. Where there is a demand for it, cogeneration the simultaneous production of power and useful heat is practiced. This heat either is used for heating purposes or is purchased by industrial enterprises in the form of process heat for their production processes. Outside Germany, too, the company contributes to public power supply with three hard-coal-fired power plants, capacity about 1,700 MW, in Turkey, Colombia and the Philippines. The efficient power plants of STEAG make an active contribution to a secure and sustainable supply of energy. With a gross capacity of 07 megawatts (MW) the Lünen power plant with its two units generates around 1.6 billion kilowatt-hours (kwh) of electricity annually. This is enough to supply the electricity needs of a city with around 400,000 single-family households. Currently, 1 MW of so-called traction current go to Deutsche Bahn, the German Railways. To drive their electric trains they require 16 2/ hertz (Hz) current. Households, on the other hand, use 0 Hz current. Simultaneously, based on the principle of cogeneration the plant generates about 1 million kwh th of heat. The parallel production of heat and electricity improves the degree of utilization of the input hard coal, i.e., the energy contained in the coal can be better exploited. Combined heat and power production consequently makes the cogeneration plant more efficient and thus more environment-friendly. STEAG supplies the heat to the Lünen municipal utilities network in the form of district heating. Optimal location The location of the power plant affords optimal conditions for a plant site: coal for its operations is supplied by Deutsche Bahn, which delivers as much as 7,00 tons a day. In addition, the nearby Lippe River ensures the supply of water to the plant.

3 The power plant process Up to 00 tons of hard coal per hour can be transferred from storage to the coal bunker of the Lünen power plant. From there, in the same period of time as much as 60 tons go to the coal mills. The mills pulverize the fuel, which is dried with hot air and then burned in the furnace at temperatures in excess of 1,200 C. In unit 7 of the plant, dried sewage sludge additionally is used as fuel. During combustion, hot flue gas is formed. As it passes over kilometers of tubes in the steam generator, the flue gas heats water to make steam. The steam, which reaches a temperature of about 0 C and is under high pressure, is conducted into a turbine where it impacts the turbine blades and causes the turbine shaft to rotate. Like a dynamo a connected generator produces electricity from this motion. Transformers bring the electricity up to the necessary voltage and feed it into the grid. When the steam has finished its work in the turbine it is conducted into a condenser. This is a large heat exchanger with many tubes in which cooling water circulates. The steam comes in contact with the tubes and forms droplets (condensation), much like humid air on a cold window pane. The condensed water droplets are collected and pumped back into the boiler to complete the cycle. In the process the cooling water from the condenser heats up from about 20 C to 0 C. It is piped into cooling towers where it cascades down and cools off again. A small portion evaporates and is replaced by water from the Lippe River. Only pure water vapor escapes from the cooling towers. Combined heat and power from Lünen In addition to electricity, heat is produced in Lünen. At several points in the turbines, steam is extracted to heat water under pressure to a temperature as high as 10 C for district heating purposes. Protecting the environment When coal is fired, flue gases form which contain mainly particles of ash, dust, nitrogen oxides and sulfur dioxide. For many years STEAG has been using highly effective methods to reduce the emissions of these substances. When a power plant is built today, a third of the expenditure goes into environmental protection, most of it into air pollution control. STEAG will make substantial investments in environmental protection in future too. The emissions of the power plant are continuously measured. The company s environmental protection officers monitor and evaluate the measurements. In addition they have independent bodies like the German inspecting authority TÜV make measurements. Valuable by-products The STEAG subsidiary STEAG Power Minerals GmbH is responsible for recycling the by-products of all STEAG hard-coalfired power plants in Germany. Power plant by-products which originate in the firing process are valuable and are marketed. The by-products include fly ash, boiler sand, slag tap granulate and FGD gypsum. These power plant by-products are environmentally sound and can be used in almost all applications as construction materials without impairing the soil or groundwater. Treatment is only necessary in special cases. In contrast to the natural resources which are becoming increasingly scarce, power plant byproducts will be available in the longer term, conserving natural raw materials. Site plan Zufahrt 1 Coal conveyor belts 2 Boilerhouse (steam generator) with electrostatic preci pitator Turbine house 4 DeNO x plant Ammonia storage facility 6 Granulate storage area 7 Gypsum silo 8 Fly ash silo 9 Flue gas desulfurization (FGD) plant Stack 11 Cooling tower 12 Coal yard 11 Moltkestraße Schematic illustration of the power plant process From the viewpoint of physics, energy is not produced, but merely transformed. The energy is fixed to the coal in chemical form. The coal is burned in the boiler; the released heat heats up water. This gives rise to hot steam (thermal energy) which drives a turbine (mechanical energy). A connected generator then transforms this mechanical energy into electricity (electrical energy). 1 7

4 Data and facts * Installed capacity Steam rating Steam pressure Unit 6: 17 MW Unit 7: 0 MW Total: 07 MW (incl. 1 MW traction current) Unit 6: 60 t / h Unit 7: 1,060 t / h Total: 1,620 t / h Unit 6: 206 bar Unit 7: 216 bar Steam temperature about 0 C Useful electricity output District heating (heating supplied) Annual coal consumption Steam generator Turbine unit Cooling tower Water vapor escaping from cooling tower Dust removal Flue gas desulfurization (FGD) NO x removal (DeNO x ) By-products about 1.8 billion KWh / a about 1 million kwh th / a about 700,000 t / 80,000 tce Unit 6: pulverized coal (PC) fired Benson boiler with dry ash removal and simple reheat Unit : PC-fired Benson boiler, two-pass design, with wet ash removal and simple reheat Unit 6: 17 MW three-phase condensing turbine 1 MW traction current condensing turbine Unit 7: 0 MW three-phase condensing turbine with non-regulated extraction for district heating Unit 6: open-circuit cooling with discharge cooling tower, height 22 meters Unit 7: natural-draft cooling tower, height 9 meters 00 m / h Electrostatic precipitator Lime slurry scrubbing, gypsum as final product Unit 6 / 7: low-dust DeNO x downstream of FGD Fly ash, granulate, boiler sand, gypsum A site with a tradition The history of the Lünen power plant site and its connection with STEAG goes back a long way, to the year 198, when the first plants were built to supply electricity to the aluminum plant of Vereinigte Aluminium-Werke (VAW). In 19 a 0 MW unit then was put into operation, followed in 1962 by a 10 MW unit (Boiler ) with an electrostatic precipitator. In 1966 the Gemeinschaftskraftwerk Ost GbR was formed. The objective of the involved parties Eschweiler Bergwerks-Verein, Harpen-Hoesch, Rheinstahl Energie and Steinkohlen-Elektrizität AG (STEAG) was to erect a jointly owned power plant with a capacity of 0 kw at the Lünen site. The management was entrusted to STEAG. In 1968 the new power plant entered uncharted territory: the first flue gas desulfurization pilot plant based on the activated coke process was put into operation there. In 1971 the STEAG- Bischoff sulfur dioxide scrubbing plant took up service. The 0 MW unit had already gone on-line in In 197 a new 170 MW unit followed. This was the first power plant unit to use pressure coal gasification and an integrated combined gas and steam turbine process. One year later the first flue gas desulfurizing pilot plant based on the lime slurry scrubbing process was put into service. Since 200 the power plant also supplies district heating to Lünen households. Construction and initial start-up Operator Owner : range-type power plant, 8 boilers + 4 x 4 MW turbine generators 194: 0 MW unit 1962: 10 MW unit (Unit 6) 1970: 0 MW unit (Unit 7) 197: 170 MW combined-cycle plant (pressure coal gasification) 1984: 1 MW traction current turbine generator added to 10 MW unit STEAG GmbH STEAG GmbH STEAG refers to the gross maximum capacity under nominal conditions as installed capacity. This is the continuous output that can be attained under normal conditions. It is limited by the weakest part of the plant (bottleneck), is determined by measurement and converted to normal conditions; stated in MW, calculated as MW electric and equivalent (thermal output). The standard coal equivalent or ton of coal equivalent (tce) is a commonly used unit of measure in Central Europe, though not a statutory unit of measure, to compare the energy content of primary energy sources. 1 ton coal equivalent = gigajoules (GJ) = thermal megawatt-hours (MWh th ). * as at December 1, 2011

5 STEAG GmbH Rüttenscheider Strasse Essen Germany Phone Fax info@steag.com Kraftwerk Lünen Moltkestrasse Lünen Germany Phone Fax kraftwerk.luenen@steag.com V-UK, as at June 2012