我国在60年代才开始发展热再生式干燥机，但是在吸附剂再生过程中需要复杂的加热设备及蒸气锅炉等，且耗能设备费用高。70年代末，由大庆油田研究设计院和沈阳气体压缩机研究所联合研制了第一套无热再生式吸附干燥机，在国内第一次采用了无热再生流程。80年代初，长春气动元件厂生产出第一台冷干机，8个月后，无锡气源净化设备厂也研制成功。冷冻式干燥机开始迅速发展，相对于吸附式干燥机来说，其能耗相对较小，维护简单，而且对配置的空压机没有特殊的要求，对除油过滤器的要求也较低。90年代中期以来，一些企业推出了由冷冻式干燥机和变压变温吸附式干燥机有机组合而成的“组合式低露点”干燥器，并在这方面做了大胆探索。

 

In the 1960s, China began to develop hot regenerative dryer, but in the process of adsorbent regeneration, complex heating equipment and steam boilers are needed, and the cost of energy-consuming equipment is high. In the late 1970s, the first set of non-thermal regenerative adsorption dryer was developed by Daqing Oilfield Research and Design Institute and Shenyang Gas Compressor Research Institute, and the first non-thermal regeneration process was adopted in China. In the early 1980s, Changchun Pneumatic Component Factory produced the first cold-dryer. Eight months later, Wuxi Gas Source Purification Equipment Factory also developed successfully. Refrigeration dryer began to develop rapidly. Compared with adsorption dryer, its energy consumption is relatively small, maintenance is simple, and there is no special requirement for the configuration of air compressor, and the requirement for oil removal filter is also low. Since the mid-1990s, some enterprises have introduced the "combined low dew point" dryer, which is an organic combination of freeze dryer and pressure-swing temperature-swing adsorption dryer, and have made bold explorations in this regard.

 

 

 

近十几年来，随着国产冷冻式干燥机不断的改进和提高，在配置的选购上更注重部件的品质，使设备可靠性大大提高。目前，冷冻式和吸附式干燥机已成为我国工业中应用比较广的压缩空气干燥机。与此同时，蓄冷式冷干机也得到了很大的发展。蓄冷式冷干机采用充满大量蓄冷溶液的蓄冷式换热器，制冷系统产生的冷量通过蓄冷溶液来冷却压缩空气。在气量、气体状态与环境条件变化时，能稳定的提供负荷标准露点的压缩空气，无论是在部分负荷还是空负荷下运行，蓄冷式冷干机都可以在效率比较佳，工况比较安全的情况下运转，总能耗低，节能效果显著。

 

Over the past decade, with the continuous improvement and improvement of domestic freeze dryer, more attention has been paid to the quality of components in the selection and purchase of configuration, which greatly improves the reliability of equipment. At present, freezing and adsorption dryers have become the most widely used compressed air dryers in China's industry. At the same time, the cold storage dryer has also been greatly developed. The regenerative cold dryer uses a regenerative heat exchanger filled with a large number of cold storage solutions. The refrigeration system generates cooling capacity through the cold storage solution to cool compressed air. When the air volume, gas state and environmental conditions change, the compressed air which can provide the standard dew point of load can be stable. Whether it is operated under partial load or no load, the cold storage chiller can operate under the best efficiency and the safest working condition. The total energy consumption is low and the energy saving effect is remarkable.

 

 

压缩空气气水分离装置的种类及性能比较干燥机的种类很多，按工作原理可分为吸附式干燥机、冷冻式干燥机、潮解式干燥机、渗膜式干燥机以及组合式干燥机等。

 

Compressed air-water separator has many kinds and performances. According to its working principle, it can be divided into adsorption dryer, freezing dryer, deliquescence dryer, infiltration dryer and combined dryer.

 

冷冻式干燥机

 

Freeze dryer

 

 

 

冷冻式干燥机的工作原理，是利用全封闭式压缩机制冷系统，对经空压机排出的压缩气体冷却降温，使压缩空气温度降至露点温度以下，从而使得其中所含的大量水蒸气凝结成液滴析出，再由自动排水阀排出，得到干燥纯净的压缩空气。进口处的潮湿空气先进入热交换器，利用经蒸发器冷却后的压缩空气的冷量对其进行预冷，从而减轻了制冷系统的热负荷，达到节约能源的目的。另一方面，低温压缩空气经热交换器温度得到回升，使排气管道外壁不至于因温度过低而出现结露现象。冷干机在运行时，对环境温度较为敏感，大容量冷干机需要消耗较多的冷却水，这给高寒地区、干旱地区的应用带来了限制。而且，由于冷冻式干燥机使用的是制冷技术，饱和空气中含有的水分在低于冰点时，容易产生冰堵。所以，冷冻式干燥机的压力露点通常情况下无法达到0℃以下。在一些应用优先域中，用冷干机还达不到需要的干燥度，如气动仪表、电子工厂等。

 

The working principle of the freeze dryer is to cool the compressed gas discharged by the air compressor by using the refrigeration system of the fully enclosed compressor, so that the temperature of compressed air can be lowered below the dew point temperature, so that a large amount of water vapor contained in the freeze dryer can condense into droplets, and then be discharged by the automatic drainage valve to obtain a dry and pure one. Compressed air. The humid air at the inlet enters the heat exchanger first, and uses the cooling capacity of the compressed air cooled by the evaporator to pre-cool it, thus reducing the heat load of the refrigeration system and achieving the purpose of saving energy. On the other hand, the temperature of low-temperature compressed air is raised by the heat exchanger, so that the outer wall of the exhaust pipe does not dew because of the low temperature. When the chiller is running, it is sensitive to the environment temperature, and the large capacity chiller needs to consume more cooling water, which restricts the application of the chiller in the alpine and arid areas. Moreover, because the freeze dryer uses refrigeration technology, when the moisture content in saturated air is below freezing point, it is easy to produce ice jam. Therefore, the pressure dew point of freeze dryer usually can not reach below 0 C. In some application fields, the drying degree needed by the cold dryer can not be reached, such as pneumatic instruments, electronic factories and so on.

 

吸附式干燥机

 

Adsorption type dryer

 

 

 

吸附式干燥机属于固体除湿法，采用的吸附剂主要有硅胶、铝胶和分子筛。这些吸附材料都有很大的比表面、适宜的孔结构和表面结构，当吸附材料表面水蒸气压力小于空气中的水蒸气表面分压力时，压缩空气中的水分就被吸附。因此，吸附式干燥机可以达到较低的干燥度，压力露点可达-20℃～-100℃。当吸附剂吸附饱和后必须进行脱附再生，才能重复使用。所以一般采用两个吸附塔交替工作，使机组连续运行。其工艺一般为无油空压机—后冷却器—储气罐—油水分离器—过滤器—再生干燥—用户。此外，吸附剂对空气中的含油量比较敏感，含油量大时，吸附剂失去作用。所以，吸附干燥机需要与无油空压机配套使用。

 

Adsorption dryer belongs to solid dehumidification method. The adsorbents used are mainly silica gel, aluminium gel and molecular sieve. These adsorbents have large specific surface area, suitable pore structure and surface structure. When the surface vapor pressure of the adsorbent is less than the surface partial pressure of the vapor in the air, the water in the compressed air is adsorbed. Therefore, the adsorptive dryer can achieve a lower drying degree, and the pressure dew point can reach - 20 C to - 100 C. When the adsorbent is saturated, it must be desorbed and regenerated before it can be reused. Therefore, two adsorption towers are generally used to work alternately, so that the unit can run continuously. Its process is generally oil-free air compressor-aftercooler-gas storage tank-oil-water separator-filter-regenerative drying-user. In addition, the adsorbent is sensitive to the oil content in the air. When the oil content is high, the adsorbent loses its function. Therefore, the adsorption dryer needs to be matched with the oil-free air compressor.

 

 

 

吸附剂再生的方法有变压吸附和变温吸附两种。变温吸附是在较高的温度下将被吸附的气体从吸附剂中脱附出来，由于常用的吸附剂比热容较大而热导率较小，所以脱附时间长，还需配备相应的加热和冷却设备，能耗和投资相对较高。目前，属于变温吸附的有热再生吸附干燥机实际使用已越来越少。变压吸附是在较低的分压力下，甚至真空状态，使被吸附气体进行脱附的过程。吸附循环周期只需短短几分钟，吸附热不需散失完全即可供脱附使用，吸附床温度变化小，这些优点使得属于变压吸附的无热再生干燥机得到了广泛的应用。

 

There are two methods for regeneration of adsorbents: pressure swing adsorption and temperature swing adsorption. Variable temperature adsorption is the desorption of adsorbed gases from adsorbents at higher temperatures. Because of the large specific heat capacity and low thermal conductivity of commonly used adsorbents, the desorption time is long, and the corresponding heating and cooling equipment is needed. The energy consumption and investment are relatively high. At present, there are fewer and fewer heat regeneration adsorption dryers which belong to variable temperature adsorption. Pressure swing adsorption (PSA) is a process of desorption of adsorbed gases under low partial pressure, even in vacuum. The adsorption cycle takes only a few minutes, and the heat of adsorption can be used for desorption without losing completely. The temperature of the adsorbent bed changes little. These advantages make the non-thermal regenerative dryer which belongs to pressure swing adsorption widely used.

 

 

 

虽然吸附式干燥机运行稳定可靠，但是由于要对吸附饱和的空气进行再生，因此能耗较大，消耗空气量较大，所列为几种吸附式干燥机的主要技术参数。采用节能技术措施降低吸附式干燥器能耗，降低企业的生产成本，提升企业竞争力有着明显的现实意义。目前，利用空压机余热为吸附剂再生能源的技术得到广泛的使用和发展。

 

Despite the stable and reliable operation of the adsorption dryer, due to the regeneration of saturated adsorbed air, energy consumption and air consumption are large, which are listed as the main technical parameters of several adsorption dryers. It has obvious practical significance to adopt energy-saving technical measures to reduce energy consumption of adsorption dryer, reduce production costs of enterprises and enhance competitiveness of enterprises. At present, the technology of using waste heat of air compressor as adsorbent renewable energy has been widely used and developed.

 

潮解式干燥机

 

Deliquescent dryer潮解式干燥机也是利用吸附剂对水分的吸附性能进行空气干燥，只不过潮解式吸附剂在吸附水分后变成液态排出，因此叫做“潮解”。经过再生，潮解后的液态又恢复为固态。常用的吸附剂有氯化钙、五氧化二磷、苛性钠和苛性钾等，这些材料表面水蒸气分压力低于周围空气的水蒸气分压力，因而具有很强的亲水性。采用这种装置可以达到-38℃左右的露点，但再生时处理的耗能相当大，对于价值低廉的吸附剂来说费用太高，因此只做一次性使用。潮解后的水溶液对环境污染较大，所以这种干燥机应用较少。在吸附式干燥器和冷冻式干燥器崛起后，这类干燥方法已被逐渐淘汰。