无所畏惧的流量控制
Flow control: from natural gas pipelines to LNG
执行器是石油和天然气行业中必不可少的设备项目。它们提供流量控制，这是工业应用中液体和气体的管理。在石油和天然气行业的所有三个领域都发现了流量控制设备：上游，中游和下游。本文将探讨传统管道围绕传统管道的挑战和机遇，以及在液化天然气（LNG）生产和运输中使用的管道的独特情况。
传统中游管道中的流量控制
Traditional pipelines are considered as part of midstream operations, moving oil and gas from one location to another. This can often be distances of thousands of miles. They are a vital link between the natural gas producing areas (including import and LNG terminals) and the population centres where most consumers are located. This can include natural gas that has been regasified from LNG. The necessary flow control involved maximises operational reliability and efficiency. The precision and control provided by actuators removes human error, increasing accuracy within an automated process. But the most important consideration for actuators on pipelines is arguably safety; critical safety duties are provided by actuators with fail-safe and Emergency Shutdown (ESD) functionality. Continued undesired flow of oil or gas can have environmental and human safety consequences but with effective shutdown options, impacts are lessened or negated.
控制石油和气体流动的阀可以是气动，液压或电动作用的。选择的执行器的类型取决于多个因素，例如电源，位置，所需的控制类型，正在控制哪种流体和操作频率。流体动力执行器通常是由于其故障安全性，高扭矩和推力能力以及由于其快速起作用而被选择用于大规模管道应用。经常使用适合高压气体供应的定制控制系统。流体动力执行器的类别包括气动执行器，高压气动执行器和电湿劳力执行器。弹簧回收气动执行器通常在气管和油管管道上使用，因为它们提供了实现故障安全动作的最简单，最可靠的方法。大型执行器（例如Rotork的GP范围，可以延伸到近6 m，操作阀最多为68英寸）具有板载控制面板，可用于关闭操作。这是安全功能，使它们非常适合在管道上使用。高压气动执行器用于管道上，在管道中，将管道中流动的高压气体用作执行器的电源。无需降压系统。 As well as ESD and safety functions, they can also provide other control functions such as low pressure close and line break. They are ideal for remote or hazardous environments. If necessary, they can be solar powered. Electro-hydraulic actuators are another option, combining simplicity of electrical operation with precision of hydraulic control, with the reliability of a spring to perform ESD and safety functions. Rotork’s Skilmatic actuator is a self-contained solution for remote locations and is designed for safety critical applications. It can close a valve in seconds if necessary and offers partial stroke and ESD capability as standard features. In 2018, Skilmatics were installed on a tank farm in India to fulfil an increase in demand of safety related duties as required local legislation. They operate 42" and 48" triple offset butterfly valves, providing tank overfill protection.
Large, industrial pipelines that transport natural gas run through many miles of remote, challenging terrain. Here, compressed air or even electricity can be unavailable. Gas from the pipeline can sometimes be the only available motive power for the actuator. Heavy-duty actuators of this kind provide routine and safety shutdown duties for the kind of large valves found on pipelines, especially within challenging environments such as saline, coastal locations (with high possibility of corrosion) and hot, arid, desert areas that see extreme fluctuations in temperature. For example, actuators have been installed at key points on a cryogenic LNG pipeline in northern Venezuela. The pipeline transports gas and LNG between different sites. The actuators provide control of ball valves along the pipeline and provide ESD options, supplying the high level of safety, reliability and security needed at all stages of LNG production. LNG presents its own unique challenges.
液化的天然气
为了专门针对液化天然气，天然气中游管道应用中的许多挑战也适用于液化天然气。液化天然气运输的主要方法是通过油轮/海船，但管道在终端，液化设施，储存和重新设备中也起着关键作用。安全必须始终是运营商的重要关注点。执行器提供的故障安全和ESD功能在安全可靠的操作中起着至关重要的作用，在紧急情况下关闭产品流程并防止进一步损坏。这尤其适用于通常危险和具有挑战性的环境。例如，通过安装旋转的流体动力执行器，可以增强西南智利的LNG管道。液化天然气综合体包括一个从油轮接收液化天然气的海端，以及通过管道重新宣传和分配到智利中部的工厂。重型，气动和液压执行器提供安全和关闭职责。裸露的海洋环境决定在包装控制系统和这些执行器提供的组件中使用耐腐蚀材料。位于澳大利亚昆士兰州的液化天然气遗址安装了CP和GP气动执行器，以操作蝴蝶阀； they are customised with control packages for bespoke operating duties. Large gas-over-oil actuators were installed on large mainline pipeline shutdown valves. The pipelines link natural gas production wells in the middle of Queensland to an LNG production plant at Curtis Island on the coast.
液化天然气的移动需要使用阀门和执行器，这些阀门和执行器可以承受涉及的极端寒冷温度。为了使气体转化为液体，需要-162°C。因此，带有液化天然气操作的阀门和设备必须能够在非常低的温度下运行，以在低温存储下提供所需的安全性和可靠性，对天然气进行重新认可以及在通常有害和具有挑战性的环境中运输中游阶段。通常需要低温阀。来自旋转船的GP和CP苏格兰轭执行器已在LNG终端使用，以在存储和重新化植物中操作球和蝴蝶低温阀。2020年，GP执行器安装在韩国液化天然气码头，该航站楼拥有四个LNG储罐和一个重新化厂。它们安装在终端的32英寸主管道上，并执行开放/关闭功能，以控制LNG和天然气的气态形式的流动。在紧急情况下，可以通过在任一方向上提供的故障安全功能立即切断流动。印度的天然气管道也使用了GP执行器。提供了80多种以操作埋藏的球阀，以满足ESD的要求，该要求沿着西南海岸的高容量液化天然气进口码头的879公里管道。
电动执行器在终端和相关地点的天然气和液化天然气的流动中也发挥作用。许多操作要求阀门在设定位置之间反复移动；电动执行器提供精确的操作，并具有分辨率和可重复性。IQ3电动执行器于2019年安装在马来西亚现场，该站点建造了重新设备，LNG储罐和泊位，用于装载和卸载LNG载体船。执行器现在控制从端子到载体的流动。CVQ电动执行器也已安装在澳大利亚苏拉特盆地的LNG站点上。他们在分离器上操作球阀。电动执行器由于其可靠性，安全性和效率而被珍视。许多人提供爆炸性认证，适合在危险和危险环境中使用。
Flow control for regasification
为了使LNG转变为天然气，需要进行称为重新化的过程。液化天然气的重新安装阶段通常发生在陆新元素已在陆上移动的进口码头。必须将其返回其气态状态，以通过传统管道向前运输，以用于燃料，发电和供暖。经常使用气动苏格兰轭执行器，为LNG和天然气控制执行开放/关闭功能。由于执行器内部的弹簧返回模块，可以在任一方向上提供故障安全功能。蒸发器是重新化过程的关键组成部分，其阀通常很小且紧凑。他们需要紧凑而快速的执行执行器才能操作它们。此阶段的其他应用包括控制气体插座阀，蒸气排放，油箱泵的排放和卸载阀。
结论
Both traditional large-scale pipelines (to transport natural gas across thousands of miles of land) and smaller scale pipelines for LNG production and processing require actuators. Actuators are key equipment for the control of liquids and gas, offering reliable, efficient and safe operation of the valves that sit on pipelines in a wide variety of applications across the midstream sector. Within LNG, valves are usually cryogenic and the actuators operating them must be sturdy, strong and capable of working successfully within demanding or even hazardous environments.