How state-of-the-art boiler and automation expertise have been utilized in a brand new energy plant that’s proper within the centre of a capital metropolis.
Known by locals because the ‘Wedding Cake’ resulting from its multi-tiered type on the Stockholm cityscape, the boiler home at VÃ¤rtaverket KVV8 biomass CHP plant has been shortlisted for 2 prestigious world architectural awards.
And contained in the terracotta-clad constructing in Sweden’s capital metropolis is likely one of the world’s largest biomass boilers.
The new plant is fuelled completely by biomass, which is available in chip type from throughout Sweden and additional across the Baltic area. The chips are fed into the boiler from a devoted railhead and harbor by way of a posh subterranean conveyor system all the way down to 40 metres under sea-level by way of tunnels lower into stable rock.
Mats StrÃ¶mberg, senior venture supervisor, says: “Not solely is that this one of many largest biofuel tasks on this planet, however now we have constructed it in a good area, proper within the coronary heart of the town, with a variety of the primary transferring elements and provide techniques located approach underground.”
All of the ash from the plant is transported again by way of the identical tunnels to silos on the harbor by way of a totally closed-loop conveying system.
What makes the environmental elements at VÃ¤rtaverket much more difficult is that the plant is correct subsequent to a residential space in addition to very near Ekoparken, the world’s first metropolis nationwide park.
StrÃ¶mberg says: “The goal on this metropolis is to do away with fossil fuels fully earlier than 2030. We will do that by constructing crops resembling KVV8, but in addition utilizing waste-to-heat crops for district heating and producing electrical energy in different areas. In truth, Stockholm Exergi has not too long ago introduced that coal crops within the metropolis shall be fully closed by 2022.”
The determination by Stockholm Exergi to go forward with the plan for a biomass plant to provide the town with district heating was made in February 2011.
Stockholm Exergi introduced in massive boiler suppliers proper from the start to debate technical options and logistics.
StrÃ¶mberg explains: In the case of the VÃ¤rtaverket website, we not solely had excessive calls for within the capability of the boiler, we additionally had main native metropolis planning restrictions when it got here to top and area. We wanted suppliers who understood the best way to work with this.
“To get the capability we wanted, we needed to set up a really massive boiler. That meant top in addition to width when it got here to capability.
There was no approach round it, says StrÃ¶mberg: “We needed to go underground. To do that, we needed to blast by way of stable rock, construct the boiler all the way down to 14 meters under floor and the tunnels all the way down to 40 meters under sea stage – we created a really large gap, all inside a stone’s throw of native residents. We additionally excavated the tunnels underground from the harbour to the plant for the biomass conveyors and in March 2014 we have been prepared.”
Austrian firm Andritz was awarded the contract for the boiler and all automation on the plant in December 2012. Bernhard Haimel, venture supervisor for Andritz, explains: “This was a singular venture in lots of elements, significantly the manufacture and set up of one of many world’s largest boilers, with a biofuel fed circulating fluidized mattress (CFB) and an output of 345 MW.
“What was significantly tough on this case was that we needed to match the boiler right into a restricted area similtaneously apply the easiest expertise for effectivity, together with the necessity for gas feeding by way of six spouts to make sure even distribution of the biofuels, one of many conditions for the bottom doable flue gasoline emissions.”
Andritz additionally delivered the flue gasoline cleansing system. Both SNCR and excessive mud SCR expertise is used to make sure lowest NOx and NH3 emissions. For main desulfurization of the flue gases, limestone is injected into the furnace. For dedusting, bag home filter expertise is used with the chance so as to add bicarbonate upstream the filter.
Another prime ingredient of the…