本文選題：MVR　切入點：空心槳葉干燥機　出處：《浙江工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：干燥是固液分離過程常用的單元操作,但普遍存在熱效率低、能耗高的問題。隨著世界能源危機日益加重,提高能源利用率,設(shè)計開發(fā)新型低能耗的干燥系統(tǒng)迫在眉睫。MVR技術(shù)利用壓縮機向蒸發(fā)產(chǎn)生的二次蒸汽輸入一定量的功,將二次蒸汽壓縮到加熱蒸汽的熱力狀態(tài)再循環(huán)利用。系統(tǒng)僅需消耗少量電能,且工藝簡單、操作成本低、維護(hù)方便,在海水淡化、蒸發(fā)濃縮等工業(yè)領(lǐng)域已經(jīng)成熟運用,節(jié)能效果顯著。但MVR技術(shù)在干燥領(lǐng)域的應(yīng)用和研究較少。本文將MVR技術(shù)應(yīng)用于傳導(dǎo)型干燥機,做了以下工作:提出了基于空心槳葉干燥機的MVR熱泵干燥系統(tǒng)。對系統(tǒng)進(jìn)行了能量平衡和質(zhì)量平衡過程分析,并對MVR系統(tǒng)熱力過程進(jìn)行了初步理論分析和計算。模擬計算了干燥壓力為80 kPa,壓縮比為2的狀況,結(jié)果表明:系統(tǒng)壓縮單位工質(zhì)的耗功僅為311 k J/kg,但可回收利用的冷凝潛熱達(dá)到2346 kJ/kg,二次蒸汽溫度提高了19.9℃,回收利用的熱量與輸入功的熱功比達(dá)7.54,能源利用效率大幅提升;模擬計算了同一干燥壓力不同壓縮比,以及相同壓縮比不同干燥壓力下熱泵系統(tǒng)性能的變化規(guī)律,結(jié)果表明:同一干燥壓力下,隨著壓縮比的增加,MVR熱泵干燥系統(tǒng)的COP和SMER均隨著壓縮比的增加而減小,且隨著壓縮比的增加,下降趨勢變緩;在相同的壓縮比下,隨著干燥壓力的增加,熱泵的性能系數(shù)增加不明顯。設(shè)計并建立了處理量為50 kg污泥/h的MVR熱泵空心槳葉干燥系統(tǒng)。計算選用了JY-003型空心槳葉干燥機和羅茨壓縮機,設(shè)計了進(jìn)料機和絲網(wǎng)除沫器,對輔助裝置進(jìn)行了選型。并對MVR熱泵干燥系統(tǒng)進(jìn)行了安裝和調(diào)試。采用該實驗系統(tǒng)對污泥間歇干燥的恒速階段進(jìn)行了實驗研究。結(jié)果表明:在污泥初始濕含量75%,質(zhì)量為120 kg,熱軸轉(zhuǎn)速11.3 r/min的工況下,干燥壓力80 k Pa,壓縮比從1.5增加到1.9,COP從5.3降到3.9,SMER從6.9降到5.2 kg/(kW·h),參照目前的蒸汽電價比,在干燥的恒速段,使用MVR熱泵系統(tǒng)進(jìn)行干燥,具有很高的實際價值。在干燥污泥的恒速段,降低干燥壓力、適當(dāng)減小壓縮比、選擇合適的熱軸轉(zhuǎn)速均有利于提高系統(tǒng)的運行效率;提出了優(yōu)化MVR熱泵干燥系統(tǒng)主要有兩個方向:一是提高壓縮機的效率,二是增強干燥機的傳熱性能。研究結(jié)果對促進(jìn)MVR技術(shù)在干燥中的應(yīng)用有一定的理論意義和工程應(yīng)用價值。
[Abstract]:Drying is a common unit operation in solid-liquid separation process, but there are many problems such as low thermal efficiency and high energy consumption. It is urgent to design and develop a new low energy consumption drying system. MVR technology uses the compressor to input a certain amount of work into the secondary steam generated by evaporation. The secondary steam is compressed to the thermal state of heating steam for recirculation and utilization. The system only needs a small amount of electric energy, and the process is simple, the operation cost is low, the maintenance is convenient, and the system has been mature and applied in the industrial fields such as seawater desalination, evaporation and concentration, etc. The energy saving effect is remarkable, but the application and research of MVR technology in drying field are few. In this paper, MVR technology is applied to conductive dryer, The following works are done: a MVR heat pump drying system based on hollow blade dryer is proposed. The energy balance and mass balance process of the system are analyzed. A preliminary theoretical analysis and calculation of the thermodynamic process of the MVR system are carried out. The drying pressure is 80 KPA and the compression ratio is 2. The results show that the energy consumption per unit of the system is only 311 KJ / kg, but the recoverable latent condensate heat is 2346 KJ / kg, the secondary steam temperature is increased by 19.9 鈩，

本文編號：1586209