天然气脱水装置的工艺设计

摘要

刚从井里采出来的天然气里充满了饱和水蒸气。水蒸汽可能是天然气中最令人讨厌的杂质。天然气被压缩或冷却时，水蒸汽会转变成液态或固态。液态水会加速设备的腐蚀，降低输气效率；而固态的冰则会堵塞阀门、管件甚至输气管线。为幸免出现这些问题，在天然气进入输气管网之前，必须除掉其中的部份水蒸气。

天然气工业常用的脱水方法有膨胀冷却法、加压冷却法、固体吸附剂吸附法、溶剂汲取法等。目前世界上天然气脱水应用最多的方法是溶剂汲取法中的甘醇法, 此次设计采纳三甘醇脱水。

湿气通过入口分离器，除去液态烃和固态杂质后，进入汲取塔底部。在汲取塔内向上通过充满甘醇的填料段或一系列泡帽或阀盘和甘醇充分接触，被甘醇脱去水后，再通过汲取塔内顶部的捕露网将夹带的液体留下。最后脱水后的干气离开汲取塔，通过贫甘醇冷却器( 甘醇─干气热交换器)后进入销售输气管网。

贫甘醇沿沿不断地被泵入汲取塔顶部，在塔内经溢流管向下依次流过每一个塔盘，将在塔内向上流淌的天然气中的水蒸汽汲取。吸满了水的甘醇(富甘醇)从塔底排出，通过贫甘醇缓冲器中的大的预热盘管后，通过闪蒸罐过滤器后进入重沸器上的精馏柱顶部。

本次设计要紧是脱水要紧单体设备设计，包括汲取塔、闪蒸罐、过滤分离器、甘醇再生器等设备。设计包括各设备的尺寸、物料衡算、热量衡算及设备选材。通过此设计工艺后的天然气在设计条件下水露点≤-10℃。

关键词：天然气加工；三甘醇脱水；设备设计

Abstract

Filled with saturated water vapor in the gas collected from the well out. Water vapor may be the most unpleasant impurities in natural gas. When the gas is compressed or cooled, the water vapor into a liquid or solid form. Liquid water will accelerate corrosion of the equipment, reduce the transmission efficiency; solid ice is clogged valve, pipe or gas pipeline. To avoid these problems, and must get rid of part of the water vapor before the gas into the pipeline network.

Expansion cooling method commonly used in the dehydration method of the natural gas industry, pressurized cooling method, the solid sorbent assay, solvent absorption method. The world's largest natural gas dehydration applications in the solvent absorption method glycol method, the design uses a TEG dehydration.

Moisture through the inlet separator to remove liquid hydrocarbons and solid impurities into the absorber at the bottom of. Glycol filler segment or a series of bubble cap or valve plate and glycol in the absorber within the full access to, glycol take off the water after capture gel network of the absorber to the top of the entrained liquid to stay the next. Finally after dehydration, the dry gas leaving absorber, after cooler of the poor glycol (DEG ─ dry gas heat exchanger) into the sales pipeline network.

Poor glycol along along constantly being pumped into the absorber at the top of each tray in turn flow down the tower through the overflow pipe, the water vapor absorption in the tower upward flow of gas. Glycol (rich glycol) to suck in water discharged from the bottom into the reboiler on distillation capitals, after the preheat coil in poor glycol buffer through the flash tank filter department.

This design is mainly the dehydration of the main monomer equipment design, including the absorber, flash tank, filter separators, glycol regeneration and other equipment.The design includes the size of all equipment, material balance, heat balance and equipment selection.the water dew point of natural gas≤ -10℃ in this design process in the design conditions.

Keywords: natural gas processing; TEG dehydration; equipment design