外文翻譯--比較美國煤礦礦井通風系統(tǒng)的效率

1、<p><b>　　中文2730字</b></p><p>　　比較美國煤礦礦井通風系統(tǒng)的效率</p><p>　　Craig R. Hairfield, Marshall Miller & Associates Inc, Richmond, VA</p><p>　　J. Daniel Stinnette, Mine Ven

2、tilation Services Inc, Fresno, CA</p><p><b>　　摘 要</b></p><p>　　隨著能源消耗的加劇，提高煤礦通風系統(tǒng)的效率成為了一個日益重要的課題。因為通風機的耗能占了煤礦能耗的一大部分，因此建立一個高效的通風系統(tǒng)是煤礦主動降低生產(chǎn)成本的重要途徑。通常，衡量礦井通風系統(tǒng)效率的方法是計算其容積效率，簡記作用于礦井生

3、產(chǎn)的有效風量占礦井總風量的比例。這個衡量標準的目的是用數(shù)據(jù)來對美國的礦井通風系統(tǒng)做一次全國性的比較。這項研究的成果旨在揭示當今煤礦通風系統(tǒng)的效率以及哪些因素可能導致礦井通風系統(tǒng)效率的或高或低。</p><p><b>　　容積效率的定義</b></p><p>　　礦井通風系統(tǒng)的容積效率定義為礦井的有效風量與礦井總風量的比值。大家對“有效風量”的組成還是眾說紛紜。Mc

4、Pherson把有效風量定義為：“到達工作面的風和那些用于稀釋例如：機電硐室、水泵房和充電站等硐室內(nèi)空氣的風的總和”。然而，Hartman則認為有效風量包括總回風石門風量和帶區(qū)內(nèi)風量的總和。</p><p>　　本次研究中，我們認為礦井空氣中的有效風量包括用于稀釋工作面空氣的風，還有用于主要生產(chǎn)設備（例如機電硐室、泵房以及充電站等）用風點的風量之和。在確定礦井主要風機總風量和礦井有效風量總和之后，下列公式可以用來

5、計算礦井通風系統(tǒng)效率。</p><p><b>　　（1）</b></p><p>　　通風系統(tǒng)效率值會在一個很大的范圍內(nèi)波動。McPherson的陳述中透露通風效率值可以從75%降至10%。本次研究中，礦井通風系統(tǒng)的效率值在14.5%到71.6%的范圍內(nèi)。當?shù)V井通風系統(tǒng)的效率值在一個較低的水平時，意味著主要通風機鼓出的大量的風沒有起到作用，導致了大量潛在的能源浪費。

6、</p><p>　　導致通風系統(tǒng)效率降低的因素</p><p>　　造成容積效率低下最主要的兩個因素包括漏風和流經(jīng)廢棄工作面、采空區(qū)而損失的風。</p><p>　　由于石門和填充物而產(chǎn)生的漏風可以通過改善礦井的建設以及加強維護來實現(xiàn)最小化。然而，無論礦井建設的質量有多么棒，在那些使用了大量填充物的礦井中想要避免漏風是不可能的。另外，隨著通風機風壓上升，漏風也自然

7、而然的就會增多，因此，在高風壓風機的礦井中更易于產(chǎn)生漏風。在礦井中減少漏風的一個可靠的方法是盡量避免入口處風流流向正相反的方向。這可以通過設置中立的一個甚至多個入口來分流、重建風路或者借助于防水煤柱來分流和重建風路來實現(xiàn)。當然，這需要在礦井的規(guī)劃階段就結合礦井通風系統(tǒng)來進行設計，但是這樣的規(guī)劃會在將來的礦井生產(chǎn)中節(jié)省大量通風機的運行費用。</p><p>　　新建礦井往往比進行了長時間生產(chǎn)的礦井在計算通風效率值上

8、更有優(yōu)勢。在那些老礦井中，不僅密封條件老化而產(chǎn)生大量漏洞，而且其本身就存在大量煤礦采空區(qū)。當處理這些先前為房柱式采煤法或長壁式采煤法的采空區(qū)時，從法定規(guī)程上講，必須要先用水沖洗礦井巷道，然后將其封住。由于分流到廢棄工作面和被封區(qū)的風不計入有效風量。因此，擁有大量舊巷道和密封區(qū)的煤礦往往會得到一個相對較低的通風效率值。</p><p><b>　　數(shù)據(jù)分析</b></p><

9、;p>　　通風系統(tǒng)的數(shù)據(jù)從遍布全國范圍內(nèi)各地區(qū)的23個煤礦搜集而來，這些地區(qū)主要包括：阿巴拉契亞中部和北部、西肯塔基、伊利諾斯盆地、西山地區(qū)和圣胡安盆地。在這23個煤礦中，有11個煤礦采用的是長壁采煤法，另外12個煤礦采用的是房、柱式采煤法。這23個煤礦不僅在分布地區(qū)上大相徑庭，而且在規(guī)模上也有很大差異，小到總風量為139700立方英尺每分鐘的房、柱式煤礦，大到總風量為1150000立方英尺每分鐘的長壁式煤礦。這些數(shù)據(jù)制成圖表1，

10、如下：</p><p>　　表一、不同型號礦井的總風量</p><p>　　下面是從所有煤礦搜集的信息，包括所有計算通風系統(tǒng)效率必需的數(shù)據(jù)。</p><p><b>　　● 礦井類型</b></p><p><b>　　● 主要通風機風量</b></p><p>　　● 最后

11、回風石門和回風井的風量</p><p>　　● 充電站、機電硐室及泵房的風量總和</p><p>　　長壁式煤礦通風系統(tǒng)的效率和房、柱式煤礦通風系統(tǒng)的效率有著顯而易見的差異。統(tǒng)計數(shù)據(jù)顯示，房、柱式采煤法的礦井通風系統(tǒng)效率有著較高的平均值。房、柱式采煤法礦井平均利用風量占總風量的44.4%，相反，長壁式采煤法的礦井的利用率只有33.9%。這個結果由圖表2顯示如下：</p>&l

12、t;p>　　表二、不同類型礦井的容積效率</p><p>　　下面的圖表顯示了在不同效率范圍的礦井分布情況。例如，圖表顯示，在20%-30%范圍內(nèi)的礦井數(shù)最多，為8個。</p><p>　　數(shù)據(jù)一：不同效率值的礦井數(shù)量分布圖</p><p>　　根據(jù)所有煤礦通風系統(tǒng)的效率平均值，長壁式采煤法礦井和房、柱式采煤法礦井都可以用一下圖來表示其風量利用分布。正如我們所

13、預想的一樣，絕大多數(shù)有效風量都用來為工作面服務，而只有非常少的一部分通風用于礦井設備。</p><p>　　下面就是收集到的用于礦井工作設備的風量的清單：</p><p>　　● 長壁工作面數(shù)量和連續(xù)工作的礦工組數(shù)</p><p><b>　　● 縫隙的平均高度</b></p><p>　　● 主要通風機的工作風壓<

14、;/p><p><b>　　● 進入煤壁的風</b></p><p>　　● 礦井密封處的大體數(shù)目</p><p>　　用于調查研究的所有收集到的相關數(shù)據(jù)都支持容積效率和礦井有關參數(shù)有關系。最明顯的是全風壓時期的容積效率，一個可以想到的事實是高風壓將會產(chǎn)生更多的漏風進而降低礦井容積效率。下面的圖表闡述了通風機作用和容積效率的這種關系。</p&

15、gt;<p>　　然而，我們必須對造成通風系統(tǒng)效率低下的因素的復雜性有清楚的認識。如前所述，眾所周知的是高風機風壓可以催生更多的漏洞和低通風效率。但是，也必須記得的是大型礦井往往擁有最高的風壓這一假定，也不得不假設大型礦井一般會有更多的密封處（用來封住那些潛在的漏洞）和大量可能的煤礦采空區(qū)。這些密封處和采空區(qū)仍然需要通風和密封。因此，諸多這些因素也在影響風機風壓和容積效率的關系上扮演重要的角色。</p>&l

16、t;p>　　我們發(fā)現(xiàn)容積效率和縫隙高度、連續(xù)工作礦工組數(shù)、煤礦產(chǎn)量以及煤礦密封數(shù)并沒有任何必然的聯(lián)系。因此影響通風系統(tǒng)效率、漏洞和采空區(qū)漏風的主要因素和當前所述的參數(shù)并沒有密切的關系就不足為奇了。</p><p><b>　　總結</b></p><p>　　本次研究闡述了美國煤礦通風系統(tǒng)的平均效率，大致能夠達到38%，但是仍然有相當大的提升空間，通風效率有望超

17、過70%。房柱式采煤法的煤礦通風系統(tǒng)效率稍高，大約為44%，而采用長壁式采煤法的煤礦這一效率則平均為34%。較低的通風效率一般是由于主要通風機風壓過高所致，這也意味著大型煤礦在提高礦井通風系統(tǒng)效率方面面臨更大的挑戰(zhàn)。</p><p>　　由于安全是構建一個高效的礦井通風系統(tǒng)所要考慮的首要問題，所以一個良好的通風系統(tǒng)和合理的通風設計在高效生產(chǎn)中是必須重點考慮的課題。此外，提高通風系統(tǒng)效率對降低煤礦生產(chǎn)成本也意義非凡

18、。因此，促進一個良好的通風系統(tǒng)也能使采礦作業(yè)和活動大大受益。</p><p>　　可以左右通風系統(tǒng)效率高低的因素不僅數(shù)量繁多而且關系復雜。從以上研究所得的數(shù)據(jù)來看，影響通風系統(tǒng)效率的因素很明顯不是單方面的。最普通也最常見的因素主要有：礦井漏洞的年久失修、填塞物老化、高風機風壓引起的漏風、大量采空區(qū)以及密封區(qū)所需的風。影響每一個煤礦通風系統(tǒng)效率高低的因素都是上述方面的綜合，因此，如果一個礦井有提高礦井通風系統(tǒng)效率的

19、打算，通風系統(tǒng)的設計者需要在識別、期望以及避免這些可能導致通風系統(tǒng)效率低下的因素上耗費大量的心血。</p><p><b>　　參考文獻</b></p><p>　　1. McPherson, M.J. (1993). Subsurface Ventilation and Environmental Engineering. New York, New York: C

20、hapman & Hall.</p><p>　　2. Hartman, H.L., Mutmansky, J.M., Ramani, R.J.,Wang, Y.J. (1997). Mine Ventilation and Air Conditioning. New York, New York: John Wiley and Son</p><p>　　COAL MINE VE

21、NTILATION EFFICIENCY: A COMPARISON OF US COAL</p><p>　　MINE VENTILATION SYSTEMS</p><p>　　Craig R. Hairfield, Marshall Miller & Associates Inc, Richmond, VA</p><p>　　J. Daniel St

22、innette, Mine Ventilation Services Inc, Fresno, CA</p><p><b>　　Abstract</b></p><p>　　With ever rising energy costs, it is increasingly important for mines to operate with energy effi

23、ciency. As a large portion of a mine’s energy consumption is often attributed to the operation of mine ventilation fans,maintaining an efficient ventilation system is a critical pro-active way for mining companies to red

24、uce power costs. A common way to measure a mine’s ventilation system efficiency is to calculate the volumetric efficiency,which is simply a calculation of the percentage of total mine</p><p>　　Definition of

25、Volumetric Efficiency</p><p>　　Mine ventilation volumetric efficiency is defined as the percentage of total mine air that is “usefully employed” for production. There can be room for discrepancies when consi

26、dering what constitutes being“usefully employed” for air in a mine. McPherson defines air that is usefully employed as “the sum of airflows reaching the working faces and those used to ventilate equipment such as electri

27、cal gear, pumps or</p><p>　　battery charging stations” (McPherson, 1993). Hartman considers usefully employed ventilation air to be the sum of air at the last open crosscut and belt air (Hartman,1997).For th

28、is study, mine air that is considered to be usefully employed consists of air that is used for ventilating working faces as well as air that is used for</p><p>　　equipment that is critical to production (suc

29、h as electrical gear, pumps, battery charging stations). After determining the total mine air quantity at the main fans and calculating the summation all air that is usefully employed in a mine, the following equation ca

30、n be used for calculating ventilation volumetric efficiency:</p><p>　　Equation 1. Volumetric Efficiency</p><p>　　Values for ventilation volumetric efficiency fall in a wide range. McPherson stat

31、es values may range from 75% down to 10% (McPherson, 1993). In this study, mines had efficiency values which fell within the range of 14.5% to 71.6% (shown below in Table 2). Mines with efficiency values in the lower par

32、t of this range indicate that large volumes of air are not being employed effectively, creating a potentially large and wasteful energy expense</p><p>　　Factors Affecting Efficiency Loss</p><p>

33、　　The two most significant factors that can cause lower volumetric efficiency include losses from leakage as well as the use of ventilation air to ventilate old workings,pillared/gob areas, or seals.</p><p>

34、　　Leakage through stoppings and doors can be minimized through good construction and maintenance. However,leakage is certainly inevitable when large numbers of stoppings are present in a mine, no matter how well-construc

35、ted. Additionally, the potential for leakage naturally increases with fan pressure, so mines with high operating pressure are more prone to leakage. A reliable method for avoiding leakage in a mine is to minimize connect

36、ions between entries having flows in opposite directions. This</p><p>　　Young mines often have a volumetric efficiency advantage over mines that have been in operation for a longer period of time. In older m

37、ines, not only do stoppings deteriorate over time, creating leakage, but more mined-out areas inherently exist. When dealing with previously pillared or longwalled areas, legally speaking, a mine must either ventilate th

38、ese areas with bleeder entries or seal them. Since air dedicated to ventilating old workings and seals does not count as usefully employed air; m</p><p>　　Data Analysis</p><p>　　Ventilation data

39、 was gathered from 23 mines from all regions of the country: Central and Northern Appalachia, Western Kentucky, Illinois Basin, Western Mountains and the San Juan Basin. Of the 23 mines, 11 are longwall operations and 12

40、 are Room and Pillar operations. Not only are the studied mines diverse in location, but also in size, as the total mine airflow values range from 139,700 cfm for a small room and pillar mine to 1,150,000 cfm for a large

41、 longwall operation. These data are tabulate</p><p>　　Table 1. Total Mine Intake Air Statistical Data by Mine</p><p>　　The following information was gathered from all mines; including the necess

42、ary data for calculating ventilation efficiency:</p><p>　　? mine type</p><p>　　? main mine fan airflows</p><p>　　? airflows at last open crosscuts or headgates</p><p>　

43、　? airflows at battery charging stations, electrical equipment and pump stations, etc.</p><p>　　Noticeable differences were discovered between ventilation efficiency values for longwall mines versus room and

44、 pillar mines. The data analysis shows that, on average, room and pillar mining operations tend to have higher ventilation efficiencies. The average room and pillar operation usefully employs 44.4% of its total air, as o

45、pposed to 33.9% for longwall operations. These results are shown below in Table 2.</p><p>　　Table 2. Volumetric Efficiency Statistical Data by Mine</p><p>　　The following graph (Figure 1) repres

46、ents the distribution of mines in the various ranges of volumetric efficiency. For example, the chart shows that there are a large number (8) of mining operations between the range of 20% and 30%.</p><p>　　F

47、igure 1.Statistical Distribution of Number of Mines in Each Volumetric Efficienc Value Range</p><p>　　Based on average values for all mines, both longwall and room and pillar, the following chart (Figure 2)

48、was created to illustrate the distribution of ventilation air in</p><p>　　mines. As one would expect, the majority of usefully employed air is used to ventilate the working areas, while ventilating supportin

49、g equipment is notably less.</p><p>　　The following is a list of supporting mine data that was gathered:</p><p>　　? number of longwall and continuous miner production units</p><p>　

50、　? average seam height</p><p>　　? main mine fan operating pressures</p><p>　　? airflows sweeping mine seals (intake to seal to return configuration)</p><p>　　? approximate number of

51、 seals in mine</p><p>　　All additional supporting data was gathered with the intention of investigating any possible correlations between volumetric efficiency and other mine performance parameters. The most

52、 obvious correlation occurs when plotting volumetric efficiency versus total fan pressure. One would expect that higher fan pressure would create higher volumes of leakage throughout the mine, and reducing volumetric eff

53、iciency. The following graph in Figure 3 illustrates this correlation with a power function trend</p><p>　　Figure 3. Volumetric Efficiency vs. Fan Pressure</p><p>　　However, one must keep in min

54、d the complexity of the factors behind a low ventilation efficiency value. As just stated, it is well known that higher fan pressure facilitates more leakage and lower ventilation efficiency.But keep in mind the assumpti

55、on could be made that the mines having the highest fan pressures are most likely the largest mines. It could also be assumed that the largest mines have the largest number of stoppings (creating potential leakage) as wel

56、l as a potentially high amount </p><p>　　Conclusions</p><p>　　This study illustrates that the average coal mine ventilation system in the United States is operating with reasonable volumetric ef

57、ficiency, at approximately 38%, but</p><p>　　has room for improvement as one mine shows that it is possible to reach over 70% efficiency. Room and pillar mines are operating with slightly higher efficiencies

58、 of</p><p>　　approximately 44% while longwall mines are operating with an average efficiency of 34%. The lower efficiency value for longwall operations, in combination with the correlation of high main mine

59、fan pressure to lower efficiency, illustrates that larger mines have the greatest challenges to increase their ventilation efficiency.</p><p>　　While safety is the primary concern behind maintaining an effic

60、ient ventilation system, it is also important to keep in mind that a good ventilation system and proper ventilation planning is essential to efficient production. Additionally,increasing the efficiency of a ventilation s

61、ystem can often significantly reduce power cost. It is therefore beneficial to a mining operation to keep in mind the factors and practices which can foster an efficient ventilation system.</p><p>　　The fact

62、ors behind what helps and hinders the efficiency of a ventilation system are numerous and complicated. Upon examination of the data acquired for this study, it was apparent that it is not possible to single out any singl

63、e factor that solely affects ventilation efficiency.The most common factors include: leakage caused by unmaintained or deteriorating stoppings; increased leakage due to high fan pressures; amount/area of mined-out/gob ar

64、eas requiring ventilation; and the number of seals</p><p>　　requiring ventilation. Ventilation system inefficiencies at every mine are influenced by some combination of the above factors. Therefore, if a min

65、ing operation has intentions of increasing volumetric efficiency, it is critical for its ventilation planners to be diligent in recognizing,anticipating and avoiding these complex factors which cause inefficiency in mine

66、 ventilation systems.</p><p>　　References</p><p>　　1. McPherson, M.J. (1993). Subsurface Ventilation and Environmental Engineering. New York, New York: Chapman & Hall.</p><p>