Cost-effective flexibilisation of an 80 MWe retrofitted biomass power plants : improved combustion control dynamics using virtual air flow sensors

As they deliver dispatchable renewable energy, biomass power plants are expected to play a key role in the stability of the future electricity grids dominated by intermittent renewables. Large-scale, biomass-fired power plants are often retrofitted from coal-fired plants. Such a fuel modi-fication combined with decreasing pollutant emission limits and higher requirements in terms load flexibility can lead to a decrease of the maximum power delivered by the unit. The limiting factors are partly related to the control systems of those plants. In this paper, we present the results of the upgrading of an 80 MWe, retrofitted biomass power plant that was achieved improving the dynamic control of the combustion process. Thanks to the addition of virtual air flow sensors in the control system and the re-design of the combustion control loops, the unde-sired effects of a recent 10% power increase on NOx emissions were more than compensated. The accurate control of the local NOx production in the furnace resulted in a decrease of these emissions by 15% with an increased stability. This study will help increasing the cost-effectiveness of such conversions, and facilitate the development of dispatchable, renewable power units able to contribute to the grid stability

Online adjustment of Furnace Exit Gas Temperature field using advanced infrared pyrometry: Case study of a 1500 MWthutility boiler

The Furnace Exit Gas Temperature (FEGT) is a key parameter of the combustion process in utility boilers that needs to be accurately monitored, especially in order to increase their load- and fuel-flexibility. However, neither the average FEGT nor its spatial distribution over the boiler cross section can be measured using standard equipment. Advanced pyrometry provides an accurate and efficient way to monitor the FEGT: by combining the signals from several pyrometers installed around the boiler, the FEGT 2D field can be reconstructed. In this paper, we show the results of a measurement campaign carried out on a 1500 MWth boiler using a system comprising 9 infrared pyrometers. Thanks to online adjustments of the combustion air distribution, the FEGT peak initially observed has been reduced by approximately 100oC, and the flame has been recentered.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effect of Therapeutic Exercise on Pain and Disability in the Management of Chronic Nonspecific Neck Pain: Systematic Review and Meta-Analysis of Randomized Trials.

Background. Given the prevalence of chronic nonspecific neck pain (CNSNP) internationally, attention has increasingly been paid in recent years to evaluating the efficacy of therapeutic exercise (TE) in the management of this condition. Purpose. The purpose of this study was to conduct a current review of randomized controlled trials concerning the effect of TE on pain and disability among people with CNSNP, perform a meta-analysis, and summarize current understanding. Data Sources. Data were obtained from MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Physiotherapy Evidence Database (PEDro), and Cochrane Central Register of Controlled Trials (CENTRAL) databases from their inception to August 2012. Reference lists of relevant literature reviews also were tracked. Study Selection. All published randomized trials without any restriction regarding time of publication or language were considered for inclusion. Study participants had to be symptomatic adults with only CNSNP. Data Extraction. Two reviewers independently selected the studies, conducted the quality assessment, and extracted the results. Data were pooled in a meta-analysis using a random-effects model. Data Synthesis. Seven studies met the inclusion criteria. Therapeutic exercise proved to have medium and significant short-term and intermediate-term effects on pain (g0.53, 95% confidence interval [CI]0.86 to 0.20, and g0.45, 95% CI0.82 to 0.07, respectively) and medium but not significant short-term and intermediate-term effects on disability (g0.39, 95% CI0.86 to 0.07, and g0.46, 95% CI1.00 to 0.08, respectively). Limitations. Only one study investigated the effect of TE on pain and disability at follow-up longer than 6 months after intervention. Conclusions. Consistent with other reviews, the results support the use of TE in the management of CNSNP. In particular, a significant overall effect size was found supporting TE for its effect on pain in both the short and intermediate terms