Inter-section scale inhibition method for centrifugal natural gas compressor set

Abstract

An inter-section scale inhibition method for a centrifugal natural gas compressor set includes a method a, a method b or a method c. A heat exchanger is additionally arranged at the position between an inter-section separator outlet to a next section first stage impeller inlet, an outlet pipeline at the back of a scaling section of the centrifugal natural gas compressor set is connected with an inlet of the additionally arranged heat exchanger, an outlet of the additionally arranged heat exchanger is connected with an inlet of a cooler through a pipeline, an outlet of the cooler is connected with an inlet of a separator, an outlet of the separator is connected with an inlet of a heat exchange coil pipe arranged in the heat exchanger, and an outlet of the heat exchange coil pipe is connected with an inlet of a scaling section first stage impeller. High-temperature natural gases at an outlet behind the scaling section and low-temperature natural gases emitted from the separator are exchanged, and temperature at the separator outlet after heat exchange compensates external temperature loss and is higher than the critical temperature for generating the water dew point and the hydrocarbon dew point.

Description

technical field [0001] The invention belongs to the field of oilfield natural gas external transportation systems, in particular to a scale inhibition method between centrifugal natural gas compressor units. Background technique [0002] The natural gas compression and transportation machines used in the oilfield natural gas processing and transportation stations are basically centrifugal natural gas compressors. This machine is a four-stage compression, each with four impellers, and the first and second stages are low pressure. The third and fourth sections are high pressure areas. Each segment is connected in series, and the fourth segment is exported. In the process of natural gas compression and pressurization, the natural gas of each stage comes out from the last impeller, is cooled by a cooler and a separator, and then enters the first impeller of the next stage, and is cooled and separated from the last impeller of the fourth stage and then exported. All kinds of co...

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Problems solved by technology

In the process of natural gas compression and supercharging, the natural gas in each stage comes out of the last impeller, is cooled by the cooler and separator, and then enters the first impeller of the next stage, and comes out of the last impeller of the fourth stage after being cooled and separated, and then exported. These compressor units are all imported from abroad, the design operating pressure is 4Mpa, and the price is more than 100 million RMB. As the natural gas in the oil field decreases year by year, the working efficiency of this unit gradually decreases. The performance attenuation rate is somewhat suitable, and in principle, it does not affect the export of natural gas. However, due to the qualitative process installation process of this centrifugal natural gas compressor export unit, the frequent shutdown of the unit for maintenance is always accompanied by its working process. The reason for the overhaul is that the pressure in the third stage exceeds the anti-surge value, which causes automatic protection shutdown. If the pressure is reduced and the external output, the cooling temperature of the expander is only -60°C, which seriously restricts the production of light hydrocarbons. The price of this unit is too high and only one unit is installed. It takes dozens of hours for each inspection, and the export and production of light hydrocarbons must be stopped during the inspection. The number of shutdowns and inspections is dozens of times a year, especially in winter. The number of inspections accounts for the majority, which seriously affects the sales of natural gas. And the production of light hydrocarbons will suffer an economic loss of 40,000 yuan per year, and receive strong protests from customers and tens of millions of yuan in economic compensation

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