沼氣提純設(shè)備在液化器中所能產(chǎn)生的液空量不到原來的10%,也就是說只有少量的冷量又通過液化器轉(zhuǎn)移給塔內(nèi),余下的大部分冷量將轉(zhuǎn)移給切換式換熱器,從而造成切換式換熱器過冷,中部溫度下降,熱端溫差擴(kuò)大。污氮復(fù)熱不足,若增加1℃,將使空分設(shè)備能耗增加2%左右。降低進(jìn)塔空氣溫度,不僅能提高空分設(shè)備的經(jīng)濟(jì)性,而且降低了空氣中的飽和水分含量。例如,當(dāng)空氣的絕對(duì)壓力為0.6MPa,空氣溫度由40℃降至30℃時(shí),每1kg空氣中的飽和水分含量將會(huì)減少約40%。
The amount of liquid air generated by the biogas purification equipment in the liquefier is less than 10%, that is, only a small amount of cooling capacity is transferred to the tower through the liquefier, and most of the remaining cooling capacity will be transferred to the switching heat exchanger, resulting in supercooling of the switching heat exchanger, decreasing the temperature in the middle and expanding the temperature difference at the hot end. The regeneration of waste nitrogen is insufficient. If the temperature is increased by 1 ℃, the energy consumption of air separation equipment will increase by about 2%. Reducing the air temperature into the tower can not only improve the economy of the air separation plant, but also reduce the saturated moisture content in the air. For example, when the absolute pressure of air is 0.6MPa and the air temperature is reduced from 40 ℃ to 30 ℃, the saturated moisture content in every 1kg of air will be reduced by about 40%.
因旁通空氣的溫度為進(jìn)塔空氣壓力下的飽和溫度,基本不變,所以當(dāng)膨脹量增加時(shí),膨脹機(jī)前溫度下降,膨脹后過熱度減小。如果膨脹量在上塔精餾潛力允許的范圍內(nèi),仍可全部送入上塔,則會(huì)使氧的提取率降低。反之,膨脹量減少則膨脹機(jī)前的溫度提高。沼氣提純?cè)O(shè)備貯氧球罐每隔兩年至少應(yīng)進(jìn)行一次內(nèi)部檢查,每隔5年測(cè)定一次壁厚。對(duì)腐蝕嚴(yán)重者,應(yīng)縮短上述檢查年限,并采取防腐措施。在罐的內(nèi)壁可涂以長(zhǎng)期耐腐蝕的無機(jī)富鋅涂料(由鋅粉和水玻璃為主配制而成)。設(shè)置在北方地區(qū)的球罐,在冬季停產(chǎn)時(shí)應(yīng)降壓或卸壓,以降低罐壁的工作應(yīng)力。
Because the temperature of bypass air is the saturation temperature under the air pressure into the tower, which is basically unchanged, when the expansion amount increases, the temperature in front of the expander decreases and the superheat after expansion decreases. If the expansion is within the allowable range of the distillation potential of the upper tower, it can still be sent to the upper tower, which will reduce the extraction rate of oxygen. On the contrary, if the expansion amount decreases, the temperature in front of the expander increases. The oxygen storage spherical tank of biogas purification equipment shall be internally inspected at least once every two years, and the wall thickness shall be measured every five years. For those with serious corrosion, the above inspection years shall be shortened and anti-corrosion measures shall be taken. The inner wall of the tank can be coated with long-term corrosion-resistant inorganic zinc rich coating (mainly prepared from zinc powder and water glass). For spherical tanks set in the north, the pressure shall be reduced or relieved when they are shut down in winter, so as to reduce the working stress of the tank wall.
沼氣提純設(shè)備傳熱量與傳熱面積成正比,而保冷箱的表面積并不與裝置的容量成正比,所以,隨著裝置容量的增大,相對(duì)于每立方米加工空氣的跑冷損失(單位冷損)是減小的。對(duì)一些采用管式蓄冷器的舊型空分裝置,相同容量的制氧機(jī)在保冷箱內(nèi)的設(shè)備多,相對(duì)來說表面積要大,跑冷損失也會(huì)大一些。沼氣提純?cè)O(shè)備調(diào)節(jié)中部溫度的方法主要是調(diào)整正、返流氣量的比例關(guān)系。常用的有:改變中抽氣量或環(huán)流量;改變蓄冷器(或切換式換熱器)各組間空氣進(jìn)氣量的分配,或產(chǎn)品氧、氮?dú)饬康姆峙涞取@纾胁繙囟绕撸申P(guān)小空氣進(jìn)口閥,減少空氣進(jìn)氣量或增加環(huán)流量(或中抽量)。
The heat transfer of biogas purification equipment is directly proportional to the heat transfer area, while the surface area of the cold box is not directly proportional to the capacity of the device. Therefore, with the increase of the capacity of the device, the cooling loss per cubic meter of processing air (unit cooling loss) is reduced. For some old air separation units with tubular cold accumulators, oxygen generators with the same capacity have more equipment in the cold insulation box. Relatively speaking, the surface area is larger and the cooling loss will be larger. The method of adjusting the central temperature of biogas purification equipment is mainly to adjust the proportional relationship between positive and backflow gas. Commonly used are: changing the medium extraction volume or ring flow; Change the distribution of air intake between groups of cold accumulator (or switching heat exchanger), or the distribution of product oxygen and nitrogen. For example, if the temperature in the middle is too high, turn down the air inlet valve to reduce the air intake or increase the ring flow (or intermediate extraction).