In many oil and gas fields, the flowmeter motor used in production and manufacturing is not effective in selection, and some are installed incorrectly, resulting in too large a measurement deviation. In addition, the flowmeter is a common dashboard of oil mining companies.Many kinds of flowmeters can measure crude oil, but the selection only depends on work experience and simplicity considering the purchase cost to carry out motor selection, will lose the opportunity to select the appropriate dashboard.It is not difficult to see that the proper selection and application of flowmeters is not easy.To properly and reasonably select an oil flowmeter, it is important to consider the following five elements: performance requirements, physical properties of the oil, installation requirements, natural environment standards, and cost.
Electromagnetic flowmeter selection
Flowmeter performance specification
The selection of flow meters in the performance of the provisions to consider the content: instantaneous velocity flow, total flow, ** degree, repeatability, linearity, flow scope and scope, working pressure damage, output data signal characteristics and response speed.Different precise measuring objects have different selection on the performance level of the flowmeter.For example, the measurement of foreign trade in crude oil is higher than that in other countries.Continuous and accurate measurement process management generally provides for good credibility and repeatability, and sometimes for broad scope, which should be prioritized for accurate measurement;The flowmeter does not have high precision, but it has good adaptability to the physical properties and load of crude oil.
Repeatability in process management is the key index in use, by the flow meter's basic principle and manufacturing quality decisions, but, in the concrete application of the flowmeter repeatability by many factors, such as crude oil viscosity, relative density, dry scratching influence factors such as the surrounding magnetic field, thus repeatability good sites, do not choose the natural environment, material and load damage flowmeter is more sensitive.
Capacity flowmeter is usually output by mechanical equipment or monopulse frequency to obtain the total flow immediately, with a high degree of **, suitable for measuring the total output, if need to output instantaneous velocity flow need to be equipped with the relative sending equipment.Electromagnetic induction flowmeter, ultrasonic flowmeter, etc. in the basic principle to accurately measure the material water flow to calculate the flow, not fast response, suitable for process management (such as leakage alarm), according to the cumulative calculation can also get the total flow.When the meter motor selection should consider the precise measurement of the production process by * * degrees, production flow and category of on the spot, in which within the scope of testing to ensure that the * * degrees, manufacture or management methods of flowmeter calibration cycle time, whether to free online solid liquid metrological verification on the spot, work pressure level meter, explosion-proof grade, etc.
The nominal diameter of the selected flowmeter shall be selected according to the range of flow applied to the pipeline under test and the limited flow and low flow of the selected flowmeter.General design line fluid dynamics ** water flow is defined by economic development water flow.Because the water flow is selected too low, the investment of the project is large;Water flow is too high and transportation output power is large, raising operating costs.Most flowmeters limit the flow of water flow close to or slightly higher than the economic development of the pipeline water flow, so the flow meter nominal diameter and pipe by the same probability is very large, the installation is more convenient, if not the same also can not be too big difference, generally adjacent to the first gear specification model, the choice of variable diameter pipe connection.
The category number of flowmeter is the ratio of limited flow to low flow, and the larger the value, the wider the category.Linear instrument panel has a large scope, 0.5 level capacity flowmeter is generally 10¡Ã1;The 0.2 stage capacity flowmeter is usually 5¡Ã1;The instrument panel of the discrete system is smaller, generally only 3:1, the higher the precision of the flowmeter, the smaller the category value, otherwise the category degree is large.The relationship between the two should be taken into account when adopting.
Installation level considerations
Different basic flowmeters have quite different installation requirements.For example, differential pressure flowmeters, pressurized flowmeters must be long upstream and downstream connection, some flowmeters are not specified or lower.Some flowmeters must consider the location of installation and material flow, maintenance of indoor space, installation location, etc.Flowmeter measurement performance by the installation of the harm is very big, flowmeter deviation is very big, there is a part of the improper installation caused.The factors considered in the installation level are: installation position of the flow meter, direction of oil flow, upper, middle and downstream connection, gate valve position, vibration, interference signal and maintenance of indoor space.
Horizontal installation and vertical installation of some flowmeters are different in metering performance. For example, the vertical downward flow of crude oil causes additional forces on rotating components of the flowmeter, which can significantly impair performance, linear or repeatability.The majority of flowmeter installation azimuth manufacturing manufacturers make requirements should be followed.The location of the installation also depends on the physical properties of the crude oil.Some flowmeters can be damaged if they are improperly installed in the opposite direction only when operating in a certain flow direction.The application of this flowmeter should also be aware that under the operating error criteria there will be adverse flow, if there will be a product must be installed to maintain the flowmeter.There will also be some differences in the performance of the flowmeter, which can work in both directions.The need to maintain interior space is often overlooked.Generally speaking, it should also be into the periphery of the flowmeter, easy to maintain, can be removed for the whole equipment.
Some flowmeters (such as coriolis quality flowmeters) are susceptible to vibration and torsion, and reliable support points should be considered.There is always a pressure regulating valve in the pipeline of the flowmeter.The pressure regulating valve shall be installed in the middle and downstream of the flowmeter to prevent the gate valve from spreading all the water flow over the oscillations and cavitation, thereby jeopardizing the precision of accurate measurement.
Some flowmeters will have to be fitted with additional safety guards to ensure that everything on the dashboard is working properly.For example, volume-based and pressurized flowmeters are generally installed in the upstream and downstream of the appropriate filter device, deaerator.
Physical properties of crude oil and oil pipeline load level considerations
The operation of the crude oil flowmeter is affected by the temperature of the crude oil, the working pressure of the pipeline, the relative density of the crude oil, the viscosity of the crude oil, the flow size and other factors.The chemical properties of crude oil change with temperature and working pressure.When crude oil is measured in a flowmeter, changes in temperature, operating pressure, viscosity and other factors can harm the volume of crude oil.Among them, temperature is one of the main parameters of harm in the measurement of flowmeter.A change in temperature results in a change in a number of key parameters, which changes the volume, relative density, viscosity of the crude oil and the gap between the casing and the internals of the flowmeter, thus resulting in a change in the leakage flow.
If the temperature decreases, the paraffin and coke in the crude oil adhere to the inner chamber of the shell and the member, which changes the volume of the metering chamber of the flowmeter, immediately jeopardizing the metering accuracy of the flowmeter.In the measurement of crude oil, the volumetric flowmeter is often used, the basic principle of its measurement, that is, there is a ** metering chamber in the casing of the meter, the flow meter according to the record of the frequency of filling the metering chamber to measure the volume of crude oil transported.Because meter motor rotor and measuring room wall there is a certain gap, and motor rotor and optimally suited production processing deviation, will cause leakage of the material being tested, but generally design allowable scope, thus causing additional key by flow deviation meter, viscosity, temperature, pressure and time elements such as lead to operate.
Elements of economic development
The economic development level only considers the instrument panel purchase cost is not omni-directional, but also should consider other expenses, such as note purchase cost, labor cost, maintenance and meter measurement verification cost, operating cost and accessories cost.Foreign trade transaction measurement should also be relatively measurement deviation caused by property losses.
Flowmeter operation cost is the key work if calorie consumption, including dynamic dashboard internal electrical equipment of power engineering cost, and promote fluid mechanics in the whole process to accurately measure the dashboard the amount of kinetic energy, get rid of the flowmeter due to precisely measure the working stress damage of underwater concrete can consume.Some flowmeters are powered by dry batteries, and rechargeable batteries are expensive.The underwater concrete cost is a hidden cost that is often overlooked.For example, pressure difference caused by gas pressure equipment of differential pressure instrument panel has very large frictional resistance.Electromagnetic induction flowmeters and ultrasonic flowmeters are ignored.
Flowmeters are supposed to carry out cycle time metrological verification, and the cycle time of metrological verification should be specified according to the specific application frequency of the instrument panel, but not beyond the requirements of the technical specification of metrological verification.Metrological verification costs account for a large proportion of flowmeter operating costs.Maintenance fee is the cost of maintaining all normal work of the inspection system after the instrument panel installation and delivery, including the cost of maintenance service company and spare parts.Dashboards with fitness components generally must be more maintenance work, such as replacement on time
Shanghai porcelain city instrument co., LTD. Is the world's leading instrument manufacturer, because of the excellent quality, with a good reputation quickly occupied the market, in the hearts of many customers, porcelain city is the synonym for the flow meter.Our goal is to provide high quality flow meters and excellent solutions for your engineering applications.