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1、BRITISH STANDARD BS 1756-2: 1971 Methods for The sampling and analysis of flue gases Part 2: Analysis by the Orsat apparatus Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 This British Standard, having been approved by the So
2、lid Fuel Industry Standards Committee, was published under the authority of the Executive Board on 27 October 1971 BSI 02-2000 First published March 1952 First revision January 1963 Second revision October 1971 The following BSI references relate to the work on this standard: Committee references SF
3、E/17 and SFE/17/1 Draft for approval 70/38595 ISBN 0 580 06546 4 Co-operating organizations The Solid Fuel Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial org
4、anizations: Association of Consulting Engineers British Cast Iron Research Association British Coke Research Association* British Ironfounders Association British Mechanical Engineering Confederation British Steel Industry* Chamber of Coal Traders Chemical Industries Association* Coal Utilisation Co
5、uncil Coke Oven Managers Association Combustion Engineering Association Council of Ironfoundry Associations Department of the Environment* Department of Trade and Industry* Domestic Solid Fuel Appliances Approval Scheme Electricity Council, the Central Electricity Generating Board and Area Boards in
6、 England and Wales* Gas Council* Heating and Ventilating Contractors Association Institute of British Foundrymen Institute of Fuel* Institution of Gas Engineers* Institution of Heating and Ventilating Engineers Institution of Mechanical Engineers Low Temperature Coal Distillers Association of Great
7、Britain, Ltd. National Coal Board* Society of British Gas Industries* Water-tube Boilermakers Association* Womens Advisory Council on Solid Fuel The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directl
8、y represented on the committee entrusted with the preparation of this standard: British Ceramic Research Association British Laboratory Ware Association Cement Makers Federation Institute of Petroleum Institute of Water Pollution Control Institution of Chemical Engineers Institution of Civil Enginee
9、rs Institution of Electrical Engineers Iron and Steel Institute Scientific Instrument Manufacturers Association Society of Chemical Industry Society of Glass Technology Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00
10、2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 BSI 02-2000i Contents Page Co-operating organizationsInside front cover Forewordii 1Scope1 2General1 3Components of apparatus1 4Transport of apparatus4 5Reagents4 6Preparation of apparatus8 7Method of operation8 8Calculation of results9 Figure 1 Orsat
11、apparatus2 Figure 2 Orsat burette3 Figure 3 Stopcock manifold5 Figure 4 Absorption vessel6 Figure 5 Filling tube for absorption vessel7 Figure 6 Alternative design of lower part of absorption vessel7 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (
12、c) BSI BS 1756-2:1971 ii BSI 02-2000 Foreword This standard makes reference to the following British Standards: BS 1751, General purpose glass stopcocks. BS 2775, Rubber stoppers and tubing of flexible materials for laboratory use. BS 3447, Glossary of terms used in the glass industry. This British
13、Standard was first issued in 1952 as a guide to the selection of suitable procedures for the sampling and analysis of flue gases. For the purpose of this standard, “flue gas” is defined broadly as the gaseous product arising from the combustion of fuel or from the combustion of any carbonaceous matt
14、er in materials being processed. The subsequent revision was extended to cover not only flue gases from domestic and industrial fuel-burning installations but also those from various industrial processes. The present edition is virtually unaltered except for the introduction of SI units, where neces
15、sary. The sampling and analysis of a flue gas is most often required for one or more of the following purposes: 1) checking and controlling the efficiency of combustion, 2) calculating heat balances, 3) detecting air or gas inleakage, 4) determining compositions and hence calculating volumes of wast
16、e gases, 5) determining moisture contents, 6) assessing the effect of the gas on other parts of the plant, e.g. corrosion or tube blockage, 7) determining substances likely to cause pollution of the atmosphere, 8) determining toxic gases. For the control of combustion efficiency, calculation of heat
17、 balances and detecting air inleakage, the determination of carbon dioxide, carbon monoxide and oxygen covers most practical requirements. For more precise work sulphur dioxide, hydrogen and methane must be taken into account and a separate method used for low concentrations of carbon monoxide. In a
18、ssessing the effect of flue gases on other parts of a plant and in guarding against pollution of the atmosphere, determinations of dew-point, sulphur dioxide, sulphur trioxide and nitrogen oxides may be necessary. The revised standard has been divided into the following parts: Part 1: Methods of sam
19、pling; Part 2: Analysis by the Orsat apparatus; Part 3: Analysis by the Haldane apparatus; Part 4: Miscellaneous determinations; Part 5: Semi-routine analyses. The standard deals with the following determinations: Carbon dioxide Oxygen Carbon monoxide Hydrogen Methane Moisture Dew-point Sulphur diox
20、ide Sulphur trioxide Nitrogen oxides Total oxides of sulphur Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 BSI 02-2000iii Except in Part 5, no reference has been made to modern procedures for gas analysis by chromatographic,
21、 infra-red or other physical methods, some of which form the basis of other British Standards. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does
22、not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 9 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in t
23、he amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 BSI 02-20001 1 S
24、cope This Part of this British Standard deals with the analysis of flue gases by means of the Orsat apparatus. NOTEThe titles of the British Standards referred to in this standard are listed on the page ii. 2 General The Orsat apparatus (see Figure 1) is the most common type of constant pressure gas
25、 analysis apparatus. The principle involved is the measurement of the reduction in volume which occurs when individual constituents of a gas are removed separately by absorption in liquid reagents. All measurements during an analysis are made at constant (atmospheric) temperature and pressure (Note
26、1). The simplicity of both the design of the apparatus and the technique employed enables the successive determinations to be made rapidly. The apparatus described permits replicate determinations having a standard deviation of about 0.2 %. Where greater accuracy is required the Haldane apparatus sh
27、ould be used (see BS 1756-3). 3 Components of apparatus 3.1 General. All glassware shall be constructed of clear glass, shall be as free as possible from striae and other visible defects and shall be well annealed. For field work the burette may be constructed from schellbach tubing (see BS 3447). A
28、ll capillary tubing shall be not less than 7 mm nor more than 8 mm outside diameter and not less than 1.5 mm nor more than 2.0 mm bore. All open ends of tubes shall be cut off square and flame polished. All stopcocks shall be of the best quality (see BS 1751). The bores of the plugs shall be 2 0.2 m
29、m. 3.2 Measuring burette. The measuring burette (Figure 2) shall have a capacity of 100 ml, and shall be graduated at 0.2 ml intervals over the range 0 30 ml. 3.2.1 Dimensions. The burette shall be constructed to conform to the dimensions given in Figure 2. 3.2.2 Definition of capacity. The capacity
30、 corresponding to any graduation line is defined as the volume of water at 20 C, expressed in millilitres, delivered by the burette at 20 C when emptied from that graduation line to the zero graduation line, the burette being in a vertical position and the lowest point of the water meniscus being se
31、t on the graduation line. No time is allowed for drainage. For this purpose the burette shall be operated with a restriction on outflow such that the time taken for the meniscus to move from the 30 ml line to the zero line shall be 35 10 s1). 3.2.3 Tolerances on capacity. The maximum error at any po
32、int shall be 0.1 ml and the difference between the errors at any two points on the graduated scale shall not exceed 0.1 ml. 3.2.4 Graduation lines. The graduation lines shall be fine, cleanly-etched lines of uniform thickness and shall be in planes perpendicular to the axis of the burette. There sha
33、ll be no evident irregularities in the spacing of the scale graduation lines. 3.2.5 Range and subdivision of scale. The 100 ml graduation line shall be marked on the vertical tube above the bulb. The scale shall have a range 0 30 ml, and shall be divided into intervals of 0.2 ml. The 30 ml line shal
34、l be at least 1 cm below the base of the bulb. 3.2.6 Numbering and length of graduation lines. The graduation lines indicating zero and multiples of 1 ml on the scale shall be numbered upwards. On burettes made of clear glass, these lines shall be carried completely round the tube and the number sha
35、ll be placed on the right above the line to which it refers; the intermediate lines shall be carried half-way round and aligned, as shown in Figure 2a. On burettes made of schellbach tubing, the graduation lines shall be symmetrical and confined to the front of the burette, numbered and suitably var
36、ied in length so as to emphasize zero and multiples of 1 ml, for example, as shown in Figure 2b; the number shall be placed above or centrally on the right of the relevant graduation line. The scale shall be diametrically opposed to the stripe. 1) The time of outflow is given above for the purpose o
37、f definition; the natural speed of gas intake will be much quicker than this and it is not normally necessary in use to restrict it to the same extent as indicated above. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 2 BSI 0
38、2-2000 Figure 1 Orsat apparatus Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 BSI 02-20003 Dimensions in millimetres Figure 2a Clear glass Figure 2b Schellbach Figure 2 Orsat burette (100 ml graduated 030 ml) Licensed Copy:
39、sheffieldun sheffieldun, na, Fri Nov 24 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1756-2:1971 4 BSI 02-2000 All graduation markings shall be filled with a black enamel which will not be displaced when the burette is immersed in water. 3.2.7 Inscriptions. The following inscriptions shall
40、 be permanently and legibly marked on each burette: the abbreviation “100 ml” to indicate the nominal capacity and the unit in terms of which the burette is graduated; the abbreviation “Ex.” to indicate that the burette capacity is defined by the volume of water delivered; the abbreviation “20 C” to
41、 indicate the reference temperature for calibration; an identification number; the makers or vendors name or mark; the number of this British Standard, i.e. BS 1756, followed by the letter A2). 3.3 Water jacket. The water jacket shall consist of a glass tube of the following dimensions: The burette
42、shall be held in this water jacket by means of suitably bored watertight bungs. 3.4 Levelling bottle. The levelling bottle A (see Figure 1) for the burette shall be of 125 ml nominal capacity fitted with a bottom tubulure riffled for rubber tube connection. 3.5 Stopcock manifold. The stopcock manifo
43、ld H connecting the burette with the absorption bulbs shall be constructed to conform to the dimensions given in Figure 3. 3.6 Absorption vessels. The absorption vessels G1 G4 (see Figure 1 and Figure 4) shall be constructed to conform to the dimensions shown, to give a net capacity of 110 5 ml. Eac
44、h vessel shall be packed with glass tubing, the pieces of tubing being vertical and approximating in length to that of the central cylindrical portion of the vessel. In addition, the tubing in the vessels G3 and G4, used for the cuprous chloride reagent, shall contain spirals of copper wire to keep
45、the reagent in the reduced state (see Figure 5). A perforated dome is incorporated in each vessel at the bottom of the absorption limb, to prevent obstruction of the exit by the glass tubes. The open end of each absorption vessel shall be closed by a rubber bung containing a piece of capillary tubin
46、g. An alternative design for the lower part of the vessel containing the glass tubes, similar to that shown in Figure 6, is permissible, provided that the metal gauze is not attacked by the reagents employed and that suitable precautions are taken against accidental dislodgement of the means of clos
47、ure adopted. 4 Transport of apparatus The apparatus detailed may be contained in a case of minimum internal dimensions 330 mm by 470 mm by 115 mm, fitted with removable front and back panels, and with a handle for carrying purposes. The design of the case is not mandatory. 5 Reagents The following s
48、pecial reagents are required. 1) For carbon dioxide vessel G1. Potassium hydroxide solution. A 400 g/l aqueous solution of potassium hydroxide (Note 2). The absorbing power is about 40 ml of carbon dioxide per millilitre of solution3). 2) For oxygen vessel G2 a. Alkaline pyrogallol solution. Three v
49、olumes of a 400 g/l aqueous solution of pyrogallol with five volumes of a 360 g/l aqueous solution of potassium hydroxide. The absorbing power is about 14 ml of oxygen per millilitre of solution. b. Acid chromous chloride solution. Wash 8 g of zinc granules (1.7 2.8 mm) with hydrochloric acid (2N approx.). Add 250 g of pure mercury, cover with 5 ml of hydrochloric acid (2N approx.) and heat for 1 h on a water bath in an efficient fume cupboard. Allow to cool, wash the amalgam with sulphuric acid (2N approx.) and