一、羅茨鼓風(fēng)機(jī)是污水處理工程中常用的充氧設(shè)備,在污水廠風(fēng)機(jī)選型時(shí),風(fēng)機(jī)廠家產(chǎn)品樣本上給出的均是標(biāo)準(zhǔn)進(jìn)氣狀態(tài)下的性能參數(shù),我國(guó)規(guī)定的風(fēng)機(jī)標(biāo)準(zhǔn)進(jìn)氣狀態(tài): 壓力p0 =101. 3 kPa ,溫度T0 = 20 ℃,相對(duì)濕度φ= 50 % ,空氣密度ρ= 1. 2 kg/ m3 。
1、 Roots blower is a commonly used oxygenation equipment in sewage treatment engineering. When selecting the type of fan for sewage treatment plant, the performance parameters given on the fan manufacturer's product samples are under the standard air inlet state. The standard air inlet state of the fan specified in China is: pressure p0=101.3 kPa, temperature T0=20 ℃, and relative humidity φ= 50%, air density ρ= 1. 2 kg/ m3 。
然而風(fēng)機(jī)在實(shí)際使用中并非標(biāo)準(zhǔn)狀態(tài),當(dāng)鼓風(fēng)機(jī)的環(huán)境工況如溫度、大氣壓力以及海拔高度等不同時(shí),風(fēng)機(jī)的性能也將發(fā)生變化,設(shè)計(jì)選型時(shí)就不能直接使用產(chǎn)品樣本上的性能參數(shù),而需要根據(jù)實(shí)際使用狀態(tài)將風(fēng)機(jī)的性能要求,換算成標(biāo)準(zhǔn)進(jìn)氣狀態(tài)下的風(fēng)機(jī)參數(shù)來選型。
However, the fan is not in the standard state in actual use. When the environmental conditions of the fan, such as temperature, atmospheric pressure and altitude, are different, the performance of the fan will also change. The performance parameters on the product samples cannot be directly used in the design and selection of the fan. Instead, the performance requirements of the fan need to be converted into the fan parameters under the standard intake state according to the actual use state to select the fan.
二、羅茨風(fēng)機(jī)選型中應(yīng)關(guān)注鼓風(fēng)機(jī)出口壓力影響因素的分析容積式鼓風(fēng)機(jī)排氣壓力的高低并不取決于風(fēng)機(jī)本身,而是氣體由鼓風(fēng)機(jī)排出后裝置的情況,即所謂“背壓”決定的,曝氣鼓風(fēng)機(jī)具有強(qiáng)制輸氣的特點(diǎn)。
2、 In the selection of Roots blower, attention should be paid to the analysis of factors affecting the blower outlet pressure. The exhaust pressure of the volumetric blower does not depend on the blower itself, but on the device after the gas is discharged by the blower, which is determined by the so-called "back pressure". The aeration blower has the characteristics of forced gas transmission.
鼓風(fēng)機(jī)銘牌上標(biāo)出的排氣壓力是風(fēng)機(jī)的額定排氣壓力。實(shí)際上,鼓風(fēng)機(jī)可以在低于額定排氣壓力的任意壓力下工作,而且只要強(qiáng)度和排氣溫度允許,也可以超過額定排氣壓力工作。對(duì)于污水處理廠而言,排氣系統(tǒng)所產(chǎn)生的壓力(背壓) 為管路系統(tǒng)的壓力損失值、曝氣池水深和環(huán)境大氣壓力之和,若由于某種原因,如曝氣頭或管路堵塞,使管路系統(tǒng)的壓力損失增加,“背壓”也會(huì)升高,于是鼓風(fēng)機(jī)的壓力也就相應(yīng)升高;又若曝氣頭破裂或管路泄漏等原因,管路系統(tǒng)的壓力損失則會(huì)減少“, 背壓”便不斷降低,鼓風(fēng)機(jī)的壓力也隨之降低。
The exhaust pressure marked on the nameplate of the blower is the rated exhaust pressure of the blower. In fact, the blower can work at any pressure lower than the rated exhaust pressure, and can also work beyond the rated exhaust pressure as long as the strength and exhaust temperature allow. For the sewage treatment plant, the pressure (back pressure) generated by the exhaust system is the sum of the pressure loss value of the pipeline system, the water depth of the aeration tank and the ambient atmospheric pressure. If the pressure loss of the pipeline system increases due to some reason, such as the blockage of the aeration head or pipeline, the "back pressure" will also increase, so the pressure of the blower will increase accordingly; In addition, if the aerator breaks or the pipeline leaks, the pressure loss of the pipeline system will be reduced, and the "back pressure" will be continuously reduced, so will the pressure of the blower.
綜上所述,確定曝氣鼓風(fēng)機(jī)壓力時(shí),只需要鼓風(fēng)機(jī)在標(biāo)準(zhǔn)狀態(tài)下所能達(dá)到的壓力等于使用狀態(tài)下的大氣壓力、曝氣池水深和管路損失之和。
To sum up, when determining the pressure of the aeration blower, it is only required that the pressure that the blower can reach under the standard state is equal to the sum of the atmospheric pressure under the service state, the depth of the aeration tank and the pipeline loss.
三、羅茨風(fēng)機(jī)選型時(shí)應(yīng)關(guān)注鼓風(fēng)機(jī)空氣流量因素在計(jì)算污水處理的需氧量時(shí),其結(jié)果為標(biāo)準(zhǔn)狀態(tài)下所需氧的質(zhì)量流量qm (kg/ min) ,再將其換算成標(biāo)準(zhǔn)狀態(tài)下所需空氣的容積流量qv1(m3/ min) ,如果鼓風(fēng)機(jī)的使用狀態(tài)不是標(biāo)準(zhǔn)狀態(tài),例如在高原地區(qū)使用,則空氣密度、含濕量會(huì)發(fā)生變化,鼓風(fēng)機(jī)所供應(yīng)的空氣容積流量與標(biāo)準(zhǔn)狀態(tài)是相同的,而所供空氣的質(zhì)量流量將減少,有可能導(dǎo)致供氧量不足。
3、 Pay attention to the air flow factor of the blower when selecting Roots blower. When calculating the oxygen demand for sewage treatment, the result is the mass flow qm (kg/min) of the oxygen required under the standard state, and then convert it into the volume flow qv1 (m3/min) of the air required under the standard state. If the use state of the blower is not the standard state, such as in the plateau area, the air density and moisture content will change, The air volume flow supplied by the blower is the same as the standard state, but the mass flow of the air supplied will be reduced, which may lead to insufficient oxygen supply.
因此,需要計(jì)算出能供應(yīng)相同質(zhì)量流量的容積流量,即換算流量。在高原地區(qū)使用時(shí),環(huán)境大氣壓力也會(huì)發(fā)生變化,壓力比相應(yīng)升高,那么,鼓風(fēng)機(jī)的泄漏流量則會(huì)加大,這將導(dǎo)致鼓風(fēng)機(jī)所供應(yīng)的空氣容積流量減少,也可能造成供氧量不足。
Therefore, it is necessary to calculate the volume flow that can supply the same mass flow, that is, the converted flow. When it is used in the plateau area, the ambient atmospheric pressure will also change, and the pressure ratio will increase accordingly, so the leakage flow of the blower will increase, which will reduce the volume flow of air supplied by the blower, and may also cause insufficient oxygen supply.
因此,設(shè)計(jì)時(shí)需要考慮使用條件發(fā)生變化時(shí)各種因素的影響,以保證風(fēng)機(jī)所供應(yīng)的實(shí)際空氣流量能夠滿足使用要求,并需計(jì)算出換算流量和泄漏流量。
Therefore, the design needs to consider the influence of various factors when the service conditions change to ensure that the actual air flow supplied by the fan can meet the service requirements, and the conversion flow and leakage flow need to be calculated.
The above is a detailed introduction of Roots blower for Zhejiang sewage treatment. I hope it will be helpful to you. If you have any questions, please contact us. We will provide you with professional services http://lzdbgs.com.cn/