Smethurst P.J.,CSIRO |
Almeida A.C.,CSIRO |
Loos R.A.,Fibria Technology Center
Journal of Hydrology: Regional Studies | Year: 2015
Study region: Tropical Atlantic Forest region, Brazil. Study focus: The temporal and spatial dynamics of soil water, water table depth and stream flow in relation to precipitation and the harvesting and regrowth cycle of a Eucalyptus grandis hybrid plantation in a headwater catchment. This landscape contains a mosaic of eucalypt plantation grown for pulpwood on plateau tops and native forest reserves in gullies. Instead of harvesting the native forest to test this effect, we conducted a virtual experiment using a soil and hydrological model (HYDRUS). New hydrological insights: Plantation harvest had little effect on steam flow, despite a 6-11. m rise in water table level under the plantation area. This result suggests that the native forest reserve intercepted groundwater moving laterally between the plantation and the stream. Measured and simulated runoff coefficients were similarly low (5% and 3%, respectively), but simulated removal of the native forest led to an increase to 38%. Therefore, plantation management in this type of landscape is likely to have little impact on stream flows where there is an intact native rainforest reserve beside the stream. © 2014.
Fillat U.,Polytechnic University of Catalonia |
Roncero M.B.,Polytechnic University of Catalonia |
Bassa A.,Fibria Technology Center |
Sacon V.M.,Brazil Technology Center
Tappi Journal | Year: 2012
In this study, we examined the effect of treating eucalyptus pulp with various commercial xylanases to identify the most effective enzyme for use under the industrial bleaching conditions used at the Jacarel mill of the Brazilian firm Fibria, which include a high pH and temperature. Based on the results, the use of two of the nine enzymes studied reduced the kappa number by 1.5 units, increased brightness by 2.5% ISO, and decreased hexenuronic acids (HexA) content by more than 10 pmol/g relative to a control treatment in the absence of enzyme. The most marked changes in brightness were observed on application of an oxidative D stage to enzyme-treated pulp samples. Finally, the chemical oxygen demand (COD), total organic carbon (TOC), color, and turbidity of the effluents obtained at the end of the processes involving the enzymes were all higher than in the control process.
Guimaraes M.A.,Fibria Technology Center |
Tran H.,University of Toronto |
Cardoso M.,Federal University of Minas Gerais
Tappi Journal | Year: 2014
In kraft recovery boiler operation,fly ash or dust generated from black liquor combustion is mixed with the virgin black liquor in a mix tank and returned to the boiler with the as-fired black liquor. This internal recycled dust stream varies widely from boiler to boiler and from time to time and can have a great impact on the asfired black liquor flow and properties and,ultimately,on the boiler thermal performance. A new method has been developed to quickly and accurately determine the amount of internal recycled dust in r,ecovery boilers. The method is based on the difference between the total organic carbon content of the virgin black liquor and that of the as-fired black liquor. Tests using the method were performed on recovery boilers at three of Fibria's mills in Brazil. The results show that while the specific virgin black liquor solids produced at these mills were about the same,the internal recycled dust load varied widely,from as low as 4 wt% of as-fired black liquor solids fired in the boiler at one mill to as high as 15 wt% at another mill. Instead of total organic carbon values,heating values may also be used,but the result is not as accurate.