Double-Capillary Viscometer for Acid Natural Gas
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Solution Overview
Problem
Existing viscometers face challenges in accurately measuring the viscosity of natural gas, particularly when it contains corrosive gases like H2S, and struggle with precision and complexity in measuring low-viscosity fluids and corrosive environments.
Innovation Solution
A double-capillary viscometer design with Hastelloy components and a specific configuration for measuring acid natural gas viscosity, allowing for precise control of temperature and pressure, and using a method that involves helium gas reference measurements to calculate the viscosity of the acid gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional capillary viscometer is used to measure natural gas viscosity, then the measurement can be performed, but the measurement precision is insufficient especially for low-viscosity fluids and the device cannot handle corrosive gases
Solution Approach 1:
The patent employs Hastelloy alloy materials for the capillary tubes and connecting components, which are composite materials known for excellent corrosion resistance against H2S and CO2. This material selection resolves the contradiction by providing both the chemical stability needed for corrosive gas measurement and the dimensional precision required for accurate viscosity measurement.
Solution Approach 2:
The patent implements precise temperature control through a thermostat system and pressure control through adjustable pressure sources. By controlling temperature and pressure parameters, the measurement precision for low-viscosity natural gas is significantly improved while the controlled environment reduces corrosion effects on the measurement system.
2Measurement precision
If a falling body viscometer is used, then viscosity can be measured, but the structure is complicated and automated measurement is difficult to achieve
Solution Approach 1:
The patent replaces the complex mechanical falling body mechanism with a simple capillary flow system driven by controlled pressure differential. The viscosity measurement is achieved through flow rate measurement through the capillary tube, eliminating the need for falling bodies, guides, and complex mechanical structures while maintaining measurement capability.
Solution Approach 2:
The patent extracts only the essential measurement function from the falling body viscometer by using a capillary tube flow system. The complex mechanical components (falling bodies, guides, positioning mechanisms) are removed, retaining only the core viscosity measurement principle based on flow characteristics through a controlled restriction.
3Measurement precision
If a vibrating body viscometer is used, then viscosity can be obtained without density data, but the device is complex and suitable only for small amounts of fluid samples
Solution Approach 1:
The patent uses a long capillary tube with small diameter to create a controlled flow regime. By adjusting the pressure differential and measuring the flow rate through the capillary, the system can handle larger volumes of gas samples while maintaining measurement precision, resolving the contradiction between sample quantity requirements and measurement capability.
4Measurement precision
If molecular thermodynamic calculation methods are used, then viscosity of known composition natural gas can be calculated with high precision, but the composition must be known and corrosive gases cause measurement issues
Solution Approach 1:
The patent uses a standard gas with known viscosity properties as a reference intermediary. By comparing the flow characteristics of the unknown natural gas against the standard gas under identical conditions, the system can determine the viscosity of gases with unknown compositions without requiring compositional analysis, while the Hastelloy materials protect the system from corrosive effects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides high precision, ease of operation, and reduced uncertainty in viscosity measurements, suitable for practical engineering applications, with excellent corrosion resistance and adaptable to varying temperature and pressure conditions.
Implementation Method 1
The capillary viscometer is designed based on the Hagen-poiseuille law. The main feature of a capillary viscometer is a long tube of small diameter. The viscosity of fluid flowing within the tube can be calculated by measuring the volumetric flow rate and pressure drop through the capillary.
Implementation Method 2
The atomic potential energy of helium gas is calculated by ab initio calculation, and the thermophysical properties of helium gas, the second virial coefficient and the viscosity of pure helium gas are derived.
Implementation Method 3
The viscometer is based on a new quantum calculation method for helium gas properties. Based on the physical property parameters obtained by the helium gas quantum theory simulation, the physical properties of argon gas are relatively measured.
Data Source
AI summary
The present disclosure provides a device and method for measuring viscosity of acid natural gas with high precision and a wide temperature range. The device is based on the theoretical basis of gas measurement of double-capillary method. Ground conditions (low temperature and low pressure) or formation conditions (high temperature and high pressure) can be simulated by presetting different temperatures and pressures. The viscosity change of acid gas with changes in temperature and pressure is measured. The device has fewer measuring steps, is easy to operate and has high precision, and can provide valid reference data for actual projects or experiments.