Document pmvv7vL4742xpVxQ8ogXY03Ga

348, ah 5 0*0 SO3 Qas k W d wd w d . ao .oo CHAPTER 14 H CO CO >-< O'O 0O3 core-t coCoOuj Ci 03 03 03 o0>3 ouo5 ^ o--1 00 OUJ H 03 1-H ,-( 03 03 CO CO ,t-Ot iOt^OOpCl ^^Oh-OlNO)>HOtO os io -- r-- o i~ *** eo * OiC3COC3C r^i'-eo^ -hi C ^HCT3r-03coo3coeoco Tttooco^^oooo-ocpco . ddoooo.Hoooo 1956 Guide . -oo _s a- ; . o W W-5 a 6 o^'-g. 03 00 03 03 CO 03 CO . I> 03 rt ; oo t- 00 03 03 03 03. -: CO'-'OQCO . to 03 CO --i f- eo co.o 03 co CO 03 CO 03 CO <0 eo I CO 03 03 03 00 00'- 06cOrJH^WTf*~H03O30dr^ '. rf -- -h CO CO 03 --< CO' 03 03 O- 03 CO CO . CO t> o t>* 00 '--* Tt* 03 - ^' Y-r-f*I 00 03 03 03 Q**3* 0>0i r-j ' ________ *--iC3-**,^l'-C'3. 03 r-> -H ` CO 03 03 CO eo 1--< tP 03 ' H03C3OOWWW5 ,1s- 03 CO 03 ^ -H id CO T able 6. T ypical Gas A nalyses Constituents of Gas--Percent by Volume 'Go "col Go 'oG ^ ba* ftsmfl su*- ts- 3.S S S H>OoOoQoOo g *> g oj 0fl) c `I *- G G C G G 3 a, fi, G G G gP'2l,P2*C*Q3PQ3PQS -- 03 CO ^ G 3 u & <v G Ofc) Gt. O 3 jG cT 3 > O *15 * SgS <5 3 . -o C J3 5 G O'? 6*1 *- G .51 j_ G . g Q.t. CS . 5 T*3OG>poHOoC>Qvf~fl' G ii '^f'a 'Z g ^ g e . 3 rt'gfS o'g oj 3 CQ W W ^ o Q 3 &.S CQ 00 GG t bfi bi u* a> a> c3 G && G rG m>g 1 'G<D't0J) ff.i rG > a> : ~ 2W 3d ?3: "bO3g J3-0W ^"a5,sls-|1S }? O O t. es C50 (2p2oOOOhPQPPOOS o- 00 r~* 03 co t- r-< W *-* i-t HHH s-4 o oG ____ s fc-H SS 00` r-i i-- |<sv. S3 -- as. u - Ea OJ CO H. 03 Fuels and Combustion 349 reaction, or by combinations of these processes. Liquefied petroleum gases (propane and butane) are higher hydrocarbon gases normally obtained as a by-product of oil refineries or by stripping natural gas. These two com pounds are generally gaseous under usual atmospheric conditions although they can be liquefied by the application of moderate pressures at normal temperatures. The demand for gaseous fuels has increased so tremendously during the past 25 years that few cities now can be said to depend solely on one source of supply. During peak load periods, heating demands on natural gas distribution systems may necessitate augmenting the base supply with supplemental fuels such as high Btu oil gas or liquefied petroleum gasair mixtures. The supply of manufactured gases may be similarly increased by adding natural gas, reformed refinery gases, or relatively low heating value mixtures of liquefied petroleum gas and air. In American gas practice the heating value of a gas and appliance effi ciencies are based on the gross heating value. This value is the number of Btu liberated by complete combustion, at constant pressure, of one cubic foot of gas saturated with water vapor and measured at 60 F and 30 in. of mercury, with air at the same temperature and pressure. Products of combustion are cooled to the initial temperature of the gas and air and the water formed by combustion of free and combined hydrogen is condensed to the liquid state. Classification of Gases Representative properties of gaseous fuels commonly employed for do mestic heating processes are shown in Table 6.15> 16 17 18 Natural gas contains from- 55 to 98 percent methane with various per centages of higher hydrocarbons, chiefly ethane. In addition to these components, small quantities of non-combustible gases such as carbon dioxide, nitrogen, and helium are sometimes present. Percentages of the . different components vary with the area from which natural gas is with drawn. They may even vary slightly from any given well during its lifetime but these variations are inconsequential insofar as the utilization of the gas is concerned. Heating values of natural gases vary from 900 to 1400 Btu per cu ft but the usual range for use is from 1000 to 1050 Btu (gross) per cu ft. A typical analysis is given in Table 6. Manufactured gases commonly produced are listed in Table 6. Gross, or higher, calorific values of typical send-out gases made from these, manu factured gases generally range from 500 to 600 Btu per cu ft. Due largely to the greatly increased demand for city gases the tendency during recent years has been to increase rather than to decrease heat content of manu factured gases, thus making it possible to serve more customers through the existing distribution system. Mixed gases are a result of increased distribution of natural gas, through transcontinental transmission lines, into areas having existing manufac tured gas facilities^ In such instances some gas companies supply a 600 to 800 Btu mixture (See Table 6). In some territories these mixtures are distributed as an intermediate step in changing oyer from manufactured gas to natural gas. Although the burden of adjusting installed heating and air conditioning equipment and supplying new orifices and burner equipment is generally assumed by the gas companies when the gas is changed, it is .advisable to consult the local gas company to insure that equipment is provided with proper orifices and burners when installed. Most states enforce legislation through their public service commissions