傳統空壓機供氣系統電能浪費分析
(1) 加載時(shi)的電(dian)能消耗
加載狀態是,在壓(ya)(ya)力達到最小值(zhi)(zhi)后,原(yuan)控制方(fang)式(shi)決定其(qi)壓(ya)(ya)力會繼(ji)續上升(sheng)直到最大(da)壓(ya)(ya)力值(zhi)(zhi)。在加壓(ya)(ya)過(guo)(guo)程(cheng)(cheng)中,一定要向外界釋(shi)放更多的熱(re)量,從而導致電能損(sun)失。另一方(fang)面,高于壓(ya)(ya)力最大(da)值(zhi)(zhi)的氣體在進(jin)入氣動元件前,其(qi)壓(ya)(ya)力需要經過(guo)(guo)減壓(ya)(ya)閥減壓(ya)(ya),這一過(guo)(guo)程(cheng)(cheng)同樣(yang)是一個耗能過(guo)(guo)程(cheng)(cheng)。
(2) 卸載(zai)時電能(neng)的消耗
空(kong)(kong)(kong)載(zai)(zai)(zai)狀(zhuang)態時(shi)(shi)(shi)(shi),當壓(ya)(ya)(ya)力達到壓(ya)(ya)(ya)力最大值時(shi)(shi)(shi)(shi),空(kong)(kong)(kong)壓(ya)(ya)(ya)機通過(guo)如(ru)下(xia)方法來降壓(ya)(ya)(ya)卸載(zai)(zai)(zai):關閉進氣閥使電機處于(yu)空(kong)(kong)(kong)轉狀(zhuang)態,同時(shi)(shi)(shi)(shi)將分離罐中(zhong)多余的(de)(de)壓(ya)(ya)(ya)縮空(kong)(kong)(kong)氣通過(guo)放空(kong)(kong)(kong)閥放空(kong)(kong)(kong)。這種調節方法要造成很(hen)大的(de)(de)能(neng)量浪費。據我們(men)測算,空(kong)(kong)(kong)壓(ya)(ya)(ya)機卸載(zai)(zai)(zai)時(shi)(shi)(shi)(shi)的(de)(de)能(neng)耗(hao)約占空(kong)(kong)(kong)壓(ya)(ya)(ya)機滿載(zai)(zai)(zai)運行時(shi)(shi)(shi)(shi)的(de)(de)10%~25%,這還(huan)是在(zai)(zai)卸載(zai)(zai)(zai)時(shi)(shi)(shi)(shi)間(jian)所占比例不大的(de)(de)情況下(xia)。換而(er)言之,該空(kong)(kong)(kong)壓(ya)(ya)(ya)機20%左右(you)的(de)(de)時(shi)(shi)(shi)(shi)間(jian)處于(yu)空(kong)(kong)(kong)載(zai)(zai)(zai)狀(zhuang)態,在(zai)(zai)作無用(yong)功。很(hen)明顯在(zai)(zai)加(jia)卸載(zai)(zai)(zai)供(gong)氣控制(zhi)方式下(xia),空(kong)(kong)(kong)壓(ya)(ya)(ya)機電機存在(zai)(zai)很(hen)大的(de)(de)節能(neng)空(kong)(kong)(kong)間(jian)。
傳統(tong)空(kong)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)供氣系(xi)統(tong)的(de)(de)(de)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)控制(zhi)(zhi)是(shi)(shi)上(shang)(shang)(shang)下(xia)限(xian)控制(zhi)(zhi),首先根據生產設(she)備的(de)(de)(de)最(zui)(zui)低壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)要求,設(she)定空(kong)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)輸出壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)(de)下(xia)限(xian),也(ye)就是(shi)(shi)空(kong)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)開(kai)始加載(zai)的(de)(de)(de)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li);再在(zai)最(zui)(zui)低壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)上(shang)(shang)(shang)加1帕(pa)左(zuo)右,作為空(kong)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)輸出壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)(de)上(shang)(shang)(shang)限(xian),即開(kai)始卸(xie)載(zai)的(de)(de)(de)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)。空(kong)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)的(de)(de)(de)輸出工作壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)將(jiang)(jiang)在(zai)上(shang)(shang)(shang)下(xia)限(xian)之間(jian)波動。空(kong)壓(ya)(ya)(ya)(ya)(ya)(ya)機(ji)(ji)的(de)(de)(de)功率(lv)消(xiao)耗(hao)和輸出壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)成正比。輸出的(de)(de)(de)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)越高消(xiao)耗(hao)的(de)(de)(de)功率(lv)也(ye)越大(da),從輸出壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)(de)下(xia)限(xian)到上(shang)(shang)(shang)限(xian)的(de)(de)(de)1帕(pa)的(de)(de)(de)壓(ya)(ya)(ya)(ya)(ya)(ya)差將(jiang)(jiang)多(duo)消(xiao)耗(hao)總功率(lv)的(de)(de)(de)7-10%。
在傳統供氣空(kong)壓機系統中(zhong),如果有多臺(tai)空(kong)壓機同時運行,每臺(tai)空(kong)壓機的輸出壓力都將隨著管網的壓力波(bo)動(dong)而在上下限之(zhi)間(jian)波(bo)動(dong),所(suo)以每臺(tai)機都多消(xiao)耗(hao)7-10%的額定功率。
  傳統(tong)空(kong)壓機供氣(qi)系統(tong)中運行參(can)數(shu)的設(she)定(ding)(ding)不同(tong)也會造(zao)成空(kong)壓機用電(dian)量的不同(tong),必(bi)須根據用氣(qi)工(gong)況進行設(she)定(ding)(ding),才能(neng)達(da)到(dao)最(zui)經(jing)濟的運行效果。
傳統空壓機(ji)供(gong)氣(qi)系統由于(yu)電(dian)機(ji)不允許頻(pin)繁啟動,導致在用氣(qi)量少的時候電(dian)機(ji)仍(reng)然要空載運行,浪(lang)費電(dian)能。經(jing)常卸載和加載導致整個(ge)氣(qi)網(wang)壓力經(jing)常變化,不能保持恒定的工作壓力。
空壓機的工作原理
(2)、利用變頻器(qi)的節能模式,可使電機在輕載時以最高效率運行(xing),減(jian)少不必要的電能損耗(hao);
(3)、根據嚴(yan)格的(de)EMS標(biao)準,高(gao)(gao)效的(de)PWM變頻器使(shi)用高(gao)(gao)速低耗的(de)IGBT,降低諧(xie)波(bo)失真(zhen)和電(dian)機的(de)電(dian)能損(sun)失。
(4)、可(ke)使電機起(qi)動、加載時的(de)電流平緩上升,沒有(you)任何(he)沖擊;可(ke)使電機實(shi)現軟停,避免(mian)反生電流造成的(de)危害,有(you)利于延長設備(bei)的(de)使用壽命;避免(mian)因(yin)電流峰值帶來(lai)的(de)電力公司(si)的(de)罰款;
(5)、采用變(bian)頻控制系(xi)統后,可(ke)以(yi)實時監測供氣管路中氣體的壓力,使供氣管路中的氣體的壓力保持恒定,提高生產(chan)效(xiao)率和(he)產(chan)品質量;
(6)、由于電機在高效率狀態下運行,功(gong)率因(yin)數較(jiao)高,降低(di)了無功(gong)損耗,節(jie)約了大量電能。
總之,采用(yong)恒壓(ya)(ya)供氣智能(neng)控制系統后(hou),不但可節(jie)約30~40%的電力費用(yong),延長壓(ya)(ya)縮機的使(shi)用(yong)壽命,并可實(shi)現恒壓(ya)(ya)供氣的目的,提高生產效率和(he)產品質量
變頻改造方案設計原則
某煉油廠聚丙(bing)烯供氣(qi)系統(tong)共有四臺37kW空(kong)壓機,如下圖二,是原聚丙(bing)烯空(kong)壓機供氣(qi)系統(tong)工(gong)作流(liu)程圖,采用(yong)三臺空(kong)壓機工(gong)頻供電運行,另一臺空(kong)壓機作備用(yong)。
存在問題是(shi)(shi)由于工(gong)作空壓機(ji)(ji)是(shi)(shi)用工(gong)頻供(gong)電運(yun)行(xing)(xing),始終處于滿負荷運(yun)行(xing)(xing),趕(gan)產量(liang)用氣(qi)(qi)(qi)高峰時(shi)有氣(qi)(qi)(qi)壓偏低現象(xiang);用氣(qi)(qi)(qi)低谷時(shi),特(te)別是(shi)(shi)節假(jia)日休息(xi)時(shi),供(gong)氣(qi)(qi)(qi)壓量(liang)特(te)別大(該煉油(you)廠聚丙烯(xi)供(gong)氣(qi)(qi)(qi)系統(tong)24小時(shi)運(yun)行(xing)(xing))。容(rong)易損(sun)壞(huai)排氣(qi)(qi)(qi)閥門或氣(qi)(qi)(qi)管爆裂,同(tong)時(shi)浪費了(le)電能,降(jiang)低了(le)設備使(shi)用壽命(ming)。希望恒壓供(gong)氣(qi)(qi)(qi),三臺聚丙烯(xi)空壓機(ji)(ji)均衡工(gong)作運(yun)行(xing)(xing)。