tailieunhanh - Process Engineering Equipment Handbook P2

Wet sulfate deposits: eastern North America. (Source: Environment Canada SOE 96-2, Spring 1996.) LK P, P0 S r, Dr t = reactivity index = pressure, Pa = surface area of the test panel, m2 = distance, m = time, s Pa, Pb = pressure, Pa W, W0 = power, pW Acoustic Enclosures, Turbine A-13 FIG. A-7 Trends in lake sulfate levels (North America). (Source: Environment Canada SOE 96-2, Spring 1996.) u r = particle velocity, m/s = density, kg/m3 Gas turbines that are supplied to the oil and power industries are usually given extensive acoustic treatment to reduce the inherent high noise levels to acceptable limits. The cost of this. | A-12 Acoustic Enclosures Turbine EASTERN CANADA Area receiving 20 kg ha yr of wet sulphate 1980 1981 1982 1983 1984 1985 1988 1987 1988 1989 1990 1991 1992 1993 Wet sulphate deposition in eastern North America Area receiving average wet sulphate deposition 20kg ha yr between 1980 and 1993 1980 - 1983 average deposition of 20kg ha yr 1990 - 1993 average deposition of 20kg ha yr The area in eastern North America receiving 20kg ha yr was reduced by 42 between 1980 and 1993. -too 0 500 k Notes a Wet sulphate deposition represents the weight of sulphate in precipitation ano is an indicator of acid ram. The target value of 20 kg ha yr of wet sulphate was derived from limited data available m the early 1980s and was based mainly on sport fish loss which occurs at a pH level of 5 3 and below. More recent studies suggest that a pH of is needed to protect most aquatic organisms. b The NAtChem Data Base was used for the storage and analysis of acid precipitation data c National figures on dry sulphate deposition and ail nitrate deposition are not available. Source of data Measurements and Analysis Research Division Atmospheric Environment Service Environment Canada Downsview Ontario. Map produced by State of the Environment Directorate Environment Canada. FIG. A-6 Wet sulfate deposits eastern North America. Source Environment Canada SOE 96-2 Spring 1996. LK reactivity index P P0 pressure Pa Pa Pb pressure Pa S surface area of the test panel m2 W W0 power pW r Dr distance m t time s Acoustic Enclosures Turbine A-13 Trends in lake sulphate levels by Trends in lake acidity by region 1981-1994 V g 80 Ü 70 improving j Worse I Stable Percentage of I o 3 S S è S 8 Ontario Quebec Atlantic Region Notes a For acidity Increasing pH or alkalinity implies an improving condition decreasing pH or alkalinity implies a worse condition no trend means stable b For sulphate Decreasing trends imply improving increasing trends imply worse no trend means stable. c Number of lakes Atlantic .