车用压缩天然气脱水

DEHYDRATION OF COMPRESSED NATURAL GAS USED AS VEHICLE FUEL

车用压缩天然气（ＣＮＧ）能否达到汽车使用要求，在天然气硫含量、热值等符合商品天然气规定指标的前提下，关键在于脱水。ＣＮＧ的含水量达不到要求，ＣＮＧ加气站和ＣＮＧ汽车就无法正常运行，甚至可能导致危害极大的事故发生。因此，通过什么脱水方式将ＣＮＧ 中的水含量脱到合格是至关重要的。鉴于我国地域辽阔，油气分布广，全国性管网未形成，加之各油气田处理方式各异等原因，致使我国当前送往燃料市场的商品天然气的含水量随地区不同和季节变化而不相同。因此，在设计ＣＮＧ加气站时，必须根据具体情况正确、合理地设计ＣＮＧ脱水系统。介绍了ＣＮＧ脱水的必要性，脱水深度的确定，低压、中压、高压脱水方法说明，工艺流程、主要设备特点，以及最佳脱水方案选择等。最后指出，ＣＮＧ脱水系统成败的关键在于设计，只有正确的设计才能保证ＣＮＧ 脱水系统的安全、正常运行，从而保证ＣＮＧ 加气站和ＣＮＧ汽的安全、正常运行。

The key that whether the compressed natural gas (CNG) used as vehicle fuel could meet the requirements of a vehicle in use is dehydration on the promise that sulfur content and heating value of the natural gas accord with the set indexes of commercial natural gas.If the water content in CNG is not up to the standard,the CNG filling station and CNG vehicle are disable to run,even extremely dangerous accidents will be caused.Thus,how dehydration way will be adopted to enable the water content to be up to the standard is extremely important.Owing to the reasons that the territory of China is vast,the oil and gas distribution is wide,the country wide pipe network is not formed and the processing ways are different in different oil and gas fields,etc., the water content in the commercial natural gas supplied to fuel market is different with the difference of regions and the variation of seasons.For this reason,in designing a CNG filling station,the dehydration system for CNG must be correctly and rationally designed in the light of the concrete conditions.The necessity for dehydration of CNG,the determination of dehydration degree,the directions of the low,medium and high pressure dehydration methods,the technological process,the characteristics of the main equipments and the selection of optimum dehydration plan,etc.are introduced in this paper.Finally,it is pointed out that the key to success or failure for CNG dehydration system depends on the design,because only a correct design can guarantee the CNG dehydration system to run safely and normally,and so do the CNG filling station and CNG vehicle.