The First Operational Experience of World’s Largest Biofuel Fired CFB

Author(s):  
Ari Kokko ◽  
Stig Nickull

Oy Alholmens Kraft Ab, with its unique combination of owners, was founded for the purpose of building a power station at Pietarsaari on the west coast of Finland. The power utility companies initiated the co-operation with the saw-, pulp and paper mill owners with the goal of finding a solution which maximized biomass utilization through co-firing with other fuels, to produce steam and heat in a utility sized power plant. Concept development resulted in a 240 MWe circulating fluidized bed unit with a flexible and demanding combination of fuels. The Alholmens Kraft power plant supplies process steam to the nearby UPM-Kymmene paper mill, and for district heating in Pietarsaari. The plant produces electricity for the power company owners in Finland and in Sweden. The CFB boiler steam capacity is 550 MWth (1875 MMBtu/hr), giving a maximum electric power of 240 MWe. When commissioned in autumn 2001 the boiler was one of the largest CFB boilers in the world, and the largest biofuel-burning CFB. The Alholmens Kraft CFB boiler is a multi-fuel boiler, whose main fuels are bark, wood residue and peat, with coal as a back-up fuel. Due to its location at the pulp and paper mill, high reliability and low emissions were the most important design criteria for the boiler. Steam production for the mill must be ensured all year-round, apart from during the mill’s short annual service shutdowns. Another important design consideration was the controllability of the boiler due to Nord Pool electricity production requirements. Typical regular load variation is between day and night but sometimes the load change speed requirement is quite high. This paper presents the Alholmens Kraft power plant application, and its very smooth start-up and operational experience during the first year with different fuels and fuel combinations at various load levels. The paper also describes how well the large boiler has performed with regard to the strict emission limits. The selection of design fuel contributes well towards the target for net CO2 reduction, but it also places huge requirements in terms of fuel purchasing and logistics. The volumetric fuel consumption by the boiler at full load is 1000 m3/h (35 000 ft3) of biofuel. More coal, the support and reserve fuel, is used in spring as weather conditions may cause availability problems with peat, before the new peat can be harvested and dried at the peat bogs. Coal is always available at the site. This paper presents the first year’s operational experience of the fuel logistics chain. The successful Alholmens Kraft CFB boiler project is an excellent example of the very wide fuel flexibility that is possible in a CFB unit.

2008 ◽  
Vol 43 (2-3) ◽  
pp. 161-171 ◽  
Author(s):  
Pierre Martel ◽  
Tibor Kovacs ◽  
Virginie Bérubé

Abstract Pulp and paper mill effluents have been reported to cause changes in reproductive indicators of fish in laboratory and field studies. These changes include reduced egg production and gonad size, and altered hormone levels and expression of secondary sex characteristics. We examined the performance of biotreatment plants for their potential in abating effects of pulp and paper mill effluents on fish reproduction under laboratory conditions. A bleached kraft mill effluent (BKME) treated in an aerated lagoon and a thermomechanical pulp mill effluent (TMPE) treated by aerobic sludge in a sequential batch reactor were selected for study. Mature fathead minnows (Pimephales promelas) were exposed to effluents before and after biotreatment under continuous renewal conditions for 21 days. Egg production was monitored daily, while morphometric parameters (length, weight, gonad size), secondary sexual characteristics, and steroid hormone and vitellogenin levels were measured at the end of the effluent exposure. The effluent from both mills before biotreatment impaired the reproductive capacity of minnows (egg production) at concentrations of 10 and 20% vol/vol, but not at 2% vol/vol. Exposure to biotreated effluents from both mills at concentrations of 2, 10, 20, and 40% vol/vol caused no significant differences in overall reproductive capacity of minnows as compared with controls. These results indicate that biotreatment can significantly improve the quality of a BKME and an effluent from a TMP mill with respect to the reproductive capacity of fish as determined in laboratory tests.


1992 ◽  
Vol 25 (2) ◽  
pp. 57-64
Author(s):  
C. G. Jardine

As part of the Remedial Action Plan (RAP) programs for the St. Lawrence and Spanish Rivers in Ontario, Canada, tainting evaluations were conducted using members of the Public Advisory Committees (PACs) and the RAP teams. Triangle test sensory evaluations were conducted on caged rainbow trout (Salmo gairdneri) exposed insitu upstream and downstream of the pulp and paper mill diffuser outfalls In the St. Lawrence River only, evaluations were conducted on indigenous yellow perch (Perca flavescens) caught upstream and downstream of the mill discharge . In both locations, the odour of the flesh from the caged trout exposed above the diffuser outfall was not judged significantly different from caged trout exposed downstream of the discharge. However, the indigenous perch caught downstream of the mill in the St. Lawrence River were judged by the panelists to have a significantly more objectionable odour than those caught upstream of the discharge. While the effluent tainting potential appears to have been eliminated in the Spanish River, further studies are required to determine the source and magnitude of tainting concerns in the St. Lawrence River. The sensory test and results reported here provide useful tools for evaluating the tainting potential of pulp mill discharges and for assessing perceived consumer quality of the fish exposed to these effluents.


1985 ◽  
Vol 17 (1) ◽  
pp. 223-230 ◽  
Author(s):  
P K Latola

A wastewater from an integrated paper mill with a COD of 1200 mg/dm3 was anaerobically treated in a multi-stage reactor. The BOD7 removal efficiencies of 60-75 % were achieved at maximal loading rates of 5-6 kg COD/m3d and HRT of 4-6 hours due to the granular sludge. Industrial sulphite evaporator condensates from Ca- and Na-processes were treated in anaerobic filters containing light gravel, plastic foam and power plant slag as filter media. The BOD7 removals of 78 % on average were achieved at loading rates of 1.8-3.3 kg COD/m3d with Ca-process evaporator condensates and 80 % BOD7 removals were achieved with Na-process condensates at loading rates of 3.5-4.1 kg COD/m3d.


1988 ◽  
Vol 20 (2) ◽  
pp. 143-152 ◽  
Author(s):  
A. Langi ◽  
M. Priha

The mutagenic properties of pulp and paper mill effluents were studied in three mills: bleached kraft mill with aerated lagoon treatment (Mill 1), bleached kraft mill with activated sludge treatment (Mill 2) and mechanical pulp/paper mill (Mill 3). Both treated and untreated effluents, process streams and molecular fractions were tested for mutagenicity (Ames test. Salmonella typhimurium TA100 and SCE sister chromatid exchange test, Chinese hamster ovary cells). To verify the potential environmental effects the mutagenic activity of concentrated recipient lake water (Mill 2) was also studied. The Ames mutagenicity of the bleached kraft mill effluent (BKME) originated from the first chlorination filtrate, SCE mutagenicity also occurred in the alkali extraction stage filtrate (Mill 1). No Ames mutagenicity was detected in the paper mill effluent, but it was SCE mutagenic. Activated sludge treatment of BKME removed both Ames and SCE mutagenicity, but the aerated lagoon treated BKME was still SCE mutagenic. No mutagenic activity was detected in the recipient water concentrates.


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