On-line early warning device and method for natural gas hydrate formation in pipeline transportation

Abstract

The invention discloses a pipeline natural gas hydrate formation online early-warning device and a method. The online early-warning device comprises an online data acquisition module which is directly arranged at a position of a gathering pipeline, required to be monitored, for tracking and monitoring parameters relevant to the hydrate formation condition on the whole pipeline and realizing online early warning for the hydrate formation and optimization of the injection volume of different types of natural gas hydrate inhibitors finally. According to an online early-warning method, the electrical conductivity and the temperature of the liquid phase as well as the propagation speed of ultrasonic waves in the water phase are monitored to calculate the concentration of the hydrate inhibitor and the saline concentration in the water phase of the monitored point, and the acquired parameters such as gaseous phase pressure, gaseous phase components and temperature are also considered to realize online early warning and the optimization of the injection volume of the inhibitor.

Description

technical field [0001] The invention belongs to the technical field of natural gas and relates to on-line monitoring of natural gas hydrate, in particular to an on-line early warning device and method for the formation of natural gas hydrate in pipeline transportation. Background technique [0002] Natural gas hydrate is a kind of clathrate compound formed by certain components in natural gas and liquid water under certain temperature and pressure conditions, which looks like ice but has a different crystal structure from ice. There are two main conditions for the formation of hydrates: [0003] 1. Natural gas must be under proper temperature and pressure; [0004] 2. Liquid phase water must exist. [0005] The formation of natural gas hydrate will cause blockage of pipelines, valves and equipment, which will bring great harm to the natural gas gathering and transportation system, resulting in economic losses. There are many methods to prevent hydrate formation, among whi...

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Problems solved by technology

[0003] 1. Natural gas must be under proper temperature and pressure;

[0004] 2. There must be a liquid phase of water

When designing the injection amount of natural gas hydrate inhibitor, because the calculation is too conservative, the injection amount of inhibitor is too much, resulting in economic waste and environmental pollution. In addition, with the change of seasons, the required amount of inhibitor will also change Therefore, it is necessary to use some methods to control the injection amount of the inhibitor in the upstream of the natural gas gathering and transportation pipeline. On the premise of not forming hydrate, use as little inhibitor as possible. In the existing technology, these can be achieved Functional equipment is very limited, and even less can be monitored online. The currently published similar equipment or methods mainly include: the scheme proposed by Tohidi et al. to determine the safety zone without hydrate formation by measuring the freezing point drop of water samples in natural gas gathering and transportation pipelines; A scheme proposed by Saied Mazloum et al. to determine the concentration of inhibitors in the water phase by measuring the concentration of moisture in the gas phase of natural gas gathering and transportation pipelines

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