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中国农机化学报

中国农机化学报 ›› 2023, Vol. 44 ›› Issue (4): 104-112.DOI: 10.13733/j.jcam.issn.2095-5553.2023.04.015

• 农产品加工工程 • 上一篇    下一篇

基于液气射流的负压蒸汽加热系统设计与试验

孙奉辰1,蔡红珍1, 2,祁志强1,高锋2,刘玉凤2,刘德营2   

  1. 1. 山东理工大学农业工程与食品科学学院,山东淄博,255000; 2. 淄博能源研究院,山东淄博,255399
  • 出版日期:2023-04-15 发布日期:2023-04-25
  • 基金资助:
    淄博市重点研发计划(市外校城融合)

Design and experiment of negative pressure steam heating system based on liquidair jet

Sun Fengchen1, Cai Hongzhen1, 2, Qi Zhiqiang1, Gao Feng2, Liu Yufeng2, Liu Deying2   

  • Online:2023-04-15 Published:2023-04-25

摘要: 针对当前100 ℃以下的低温加热工艺在农业、化工、食品加工业中存在加热效率低、温度难以精确维持、自动化程度低、设备成本高等问题,集成射流泵抽空技术、PLC控制技术、控温调压技术,设计开发一种基于液气射流的负压蒸汽加热系统。该系统由智能控制系统、液气射流真空循环系统、降温调压系统和循环水调节系统组成,通过液气射流泵抽空提供蒸汽负压环境,结合减温减压装置和PLC智能控制系统对负压蒸汽进行控制,实现负压蒸汽对物料的精准自动化加热。详细阐述负压蒸汽加热系统的工作原理,确定关键部件射流泵设计结构和相关参数,并对其进行流体数值模拟的相关验证,模拟结果与实际误差在10%以内,表明射流泵设计合理可靠性高。对系统的加热性能进行试验,结果表明:基于液气射流的负压蒸汽加热系统可以精确控制蒸汽温度进行加热,同时加热温度曲线平缓,快速升温阶段真空度上下浮动0.003 MPa,平衡阶段真空度上下浮动0.002 MPa,加热温度浮动也在±1 ℃,更好地适应不同物料的加热温度,在加热效率方面优于水浴加热约2倍。该研究可解决传统水浴加热显热加热不均匀、控制精度差、加热过程缓慢、生产能力较低等问题,为农产品、化工产品深加工的加热方式、系统及装置提供新的思路与参考。


关键词: 低温加热, 负压蒸汽, 精准控温, 数值模拟, 液气射流泵

Abstract: Aiming at the current problems of low heating efficiency, difficult to maintain accurate temperature, low automation and high equipment cost in agriculture, chemical and food processing industries for low temperature heating process below 100 ℃, a negative pressure steam heating system based on liquidair jet is designed and developed by integrating jet pump evacuation technology, PLC control technology and temperature control and pressure regulation technology. The system consists of intelligent control system, liquidair jet vacuum circulation system, temperature reduction and pressure regulation system and circulating water regulation system, which provides negative pressure environment of steam through liquidair jet pump evacuation, combined with temperature and pressure reduction device and PLC intelligent control system to control the negative pressure steam and realize the precise automatic heating of materials by negative pressure steam. The working principle of the negativepressure steam heating system is elaborated, the design structure and relevant parameters of the key component jet pump are determined, and the relevant verification of the fluid numerical simulation is carried out, and the simulation results are within 10% error from the actual one, which shows that the jet pump design is reasonable and reliable. The heating performance of the system is tested, and the results show that the negative pressure steam heating system based on liquidair jet can precisely control the steam temperature for heating, while the heating temperature curve is gentle, with the vacuum level fluctuating up and down by 0.003 MPa in the rapid heating stage and 0.002 MPa in the equilibrium stage, and the heating temperature fluctuation is also within ±1 ℃, which can better adapt to the heating temperature of different materials. The heating efficiency is about 2 times better than that of water bath heating. This study can solve the problems of uneven heating, poor control accuracy, slow heating process and low production capacity of traditional water bath heating, and provide new ideas and references for heating methods, systems and devices for deep processing of agricultural and chemical products.

Key words: low temperature heating, negative pressure steam, accurate temperature control, numerical simulation, liquidair jet pump

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