Discussion on the Causes of Rotor Scaling of Natural Gas Compressor

An oilfield company’s compressor station ammonia compression refrigeration device mainly caused the reduction of natural gas processing capacity and increased power consumption; severe fouling would cause

The equipment is two D10RgB centrifugal compressors imported from the United States. The compressor surges, causing the compressor vibration to exceed the standard, causing shutdowns.

The machine was put into operation in October 1998. A production accident took place in January 2002. In view of the needs of production and safety,

Overhaul, the defective parts are labyrinth seal, floating ring, radial bearing pad

In cooperation with the competent department of the station, the cause mechanism of this type of compressor rotor fouling

The thrust bearing was inspected for unit disassembly and the compressor rotor

Carry out research, give the cause analysis of centrifugal compressor rotor fouling and

Dynamic balance detection, etc. 2 "XH January to May compressor drive end

In this way, suggestions for protective treatment are proposed.

Vibration of VT-oly increases gradually, alarms are frequent for super-high, and the machine stops when super-high

Second, it was renovated in May 2 "X). Install and start the machine after renovation,

1 Cause analysis of compressor rotor fouling

After starting the machine, the vibration of VT-02X and VT-02Y is extremely high and it stops.

machine. According to the main reason for compressor vibration in the past Ren’,:]: One is the rotation

1.1 Test conditions

Sub-unbalance, the other is the increase in tile gap. Re-dismantle the machine accordingly

Gas samples and solid matter scale samples were taken from an oilfield company

Group, check compressor rotor, bearing and probe, check oil and oil system

The fifth brigade of the gas station.

Wait, after everything is normal, start the machine again and run for a certain period of time due to vibration

Gas sample analysis adopts HP-850 gas phase produced by Hewlett-Packard Company Super high shuts down again.

Chromatographic analyzer, equipped with thermal conductivity detector, the detector temperature is

The expert group argued that the cause of the accident may be

200℃, the column is a hydrogen column, the column temperature is 50℃, and it is equipped with a gas sampler;

The raw material gas of the compressor station has a high impurity content, and the compressor is running

The test conditions are: Cu is anode, 40 kV/40n1A, RS-

The solid impurities on the rotor produce fouling speed, which destroys the rotor smoothness 0.15mm.

The compressor is shut down for many times and the number of inspections increases.

The solid sample adopts Rigaku Electric D/max-rB automatic X

After the compressor rotor fouls, it is more harmful. Slight scaling will

X-ray diffractometer performs diffraction pattern analysis.

1.2 Test analysis

2(X) Received on November 5, 2007

Introduction to the first author: Lin Yujuan (1 speaker, 1 speaker), female, professor. Research direction: process equipment

In view of the actual problems, find out the

Strength analysis and structural reliability.

Physical matter, for this reason, the Daqing area at different points and different times Wanfang Data

Issue 4 Lin Yujuan, et al.: Discussion on the cause of fouling on the rotor of natural gas compressor 1029

Table 1 Natural gas composition of compressor station

The actual natural gas and raw material flow through different locations in the zone

The solid samples were analyzed, see Table 1 and Table 2 for details. From Table 1 Sample Name It can be seen from the data that the main component of the natural gas composition of the compressor station is A, gas composition, raw gas population, first-stage outlet, second-stage outlet

(Volume Fraction/%) (Volume Fraction/%) (Volume Fraction/%)

And the results of the three sampling points are close, which shows that the gas is compressing 0, 0.35 0.66 0.17

The composition changes little during transmission. And the sulfur content is basically the same Where L 1 1

1.Print 0.81

As a result, the total sulfur content is slightly reduced. Due to the continuous gas transmission, the

Low 8 6. 2 8

85.67 86. Stare

Don't be too big. However, it can be seen from Table 2 that the content of inorganic sulfur is in c o z 2.%

3.14 2.97

l.

The formation of Feo5 during moisture transmission provides the possibility. Deposited material c

Z 8 6

1.76 1.84 There is a certain amount of heavy-component organic matter, which improves the gas carrying capacity.

3.35 3.13 3. 38

i C 4

The main reason for high. 0.70 0.65 0.71

heart

2.18

2.3 Test report 1.98 2.23

i C 5

0.45 0.48 0. Diao 6

In the testing center of Harbin Institute of Technology, the first three-phase

n C S

0.77 0.89 0.82

Separator, interstage separator, separator population, solids on the filter screen None-3 l l 5

119 1 E Qiao

Can Xi (叱

Diao

The machine samples were analyzed by a series of X-ray diffraction and infrared spectroscopy, 2 6

6 240 234

Total sulfur/(叱

One of the X-ray diffraction test results is shown in Figure 1.

Table 2 Analysis of liquid and solid mixed samples in each section

Incoming gas separator One-stage three-phase separator Inter-stage separator Filter

(Mass score/%) (mass score/%) (mass score/%) (mass score/%)

Stubborn

35.7

Water 26.5 18.7 <0.2

Alkanes 53.37 Alkanes 45.92 Alkanes 45.92

Have

Aromatics 21.54 Aromatics 6.39 Aromatics 18.97

Machine 16.5 0.55 5.2 7.7

Gum 12.39 Gum 2.85 Gum 8.15

Thing

12.39

Asphaltene Asphaltene 44.84 Asphaltene 26.96

Na 0.20 Na 0.18 Na 0.14 Na

no

K 0.05 K 0.06 K 0.01 K

machine

Ca 0.30 Ca 0.30 ca 0.04 Ca

Thing

0.17 0.29

Solid tons Mg Mg rise

Fe 49 4 Fe 41.75 Fe 43 .53 Fe 52 59

body

47.8 72.9 76.1 92.1

Medium Proposed 3.5 Al 5.19 Al 2.26 Al 25 Main si 5.16 Si 11.6 S 0.75 si 1.98

want

S plus .4 S 19.6 S 17.6 S 3.52

yuan

1.34 0.11 0.13 0.48

so’ 2- so’ 2- 504 2- 5042-

Vegetarian

Acid-insoluble matter 3. is Acid-insoluble matter 1.70 Acid-insoluble matter 3.66 Acid-insoluble matter 5.29

Signal strength (au)

According to the analysis of the X-ray diffraction pattern, the compressor rotor sinks 2000

15(X) The composition of iron in solid matter is more complex, mainly including

10(X)

Feso., FeZO, and Fe3o4. The intermediate separator also includes

5oo

Feo(OH), and a very small amount of iron and silicon form complex iron-aluminosilicate

0

20 40 6()

salt. The main mineral is aluminosilicate, which is written as a visual representation

2 pit 0)

Figure I X-ray diffraction test results FeSO., Fe203, a-510: etc.

Wanfang Data

1030

Science, Technology and Engineering 8 volumes

1.4 Analysis of the cause of formation of Fe oxide units at all levels, including more iron oxides. recognize

During the transmission of raw gas containing a small amount of water, a small mineral particle may be associated with gas in the oil field (because it contains a small amount of water). Part of the HZS and the rust on the inner wall of the pipeline have generated a small amount of certain heavy hydrocarbon components, with a relatively large specific gravity and a certain degree of turning).

Iron sulfide, the rest still flows through with the gas. The formed small amount of iron sulfide is carried to various parts of the natural gas compression system, forming a product on the rotor. A part of it constitutes one of the important components of the deposit on the rotor. It is one of the main components of the sediment.

Determine the composition and structure of the deposit on the rotor, combined with the process flow, through the analysis of the solids in the incoming gas separator

Understand and investigate on-site conditions, and the gas composition and the sediments of each flow section account for about 20.5%, and the rest contains a small amount of acid-insoluble substances.

The analysis of the solid samples obtained on the previous analysis showed that the rotor is mainly carbon, which may be due to the fact that inorganic carbon oxides under certain conditions

There are two main types of deposited solid substances: one is caused by the combination of inorganic sulfide and reducing substances, which needs further study.

Iron oxides; one is minerals-"dust".

2 Suggestions to solve the problem

1.4.1 Fens in sediments. And Fe, 0, formation

The cause of compressor vibration is more complicated, and different types of compression

The reaction mechanism [3]:

The anti-vibration measures of the machine are also different [4 games]. Through the centrifugal type D10RgB

(1) Electrochemical corrosion

Analysis of the mechanism of compressor rotor fouling, it is believed that the feed gas should enter

At the cathode: 0:+2H20+4e one by one called OH-

Install a desulfurization and dust removal unit at a certain position before the primary compression

Fe3 ten+e one FeZ+

The performance indicators of the equipment must meet the following requirements:

At the anode: re-Fe, ++Ze

1) HZS removal rate meets more than 70%;

In the rust: ZFeZ++3HZo+(1 Ninja) 02

2) The removal rate of particulate matter and heavy organic components reaches 90%; One ZFe OOH+4H+

3) The equipment is resistant to gas and liquid corrosion such as wet hydrogen sulfide, and acid resistant

reZ ten+HZs one FeS+ZH ten

Alkali, good sealing, and decontamination function at any time.

Zre3++3HZs one FeZS3+6H ten

(2) Chemical corrosion 3 Conclusion

Chronic oxidation of pipe steel:

1) The main cause of fouling on the rotor of D10RgB centrifugal compressor

Fe+02一 FeO+Fe203+Fe304

The main reason is that iron oxide (Fe 2 0,) and sulfide (Fe. 5.)

1.4.2 Origin of dust in sediments

Exist, the secondary reason is that HZS corrosion equipment generates a small amount of sulfur

(1) Rusty substance on the inner wall of the conveying pipeline: Feo/

Iron.

FeZO3/Fe3o4

2) In order to avoid such problems, it is recommended to install desulfurization and dust removal.

Through the "incoming gas separator", "interstage separator" and "first stage

An integrated device that meets the corresponding performance indicators.

Solid-liquid mixed samples removed from the "three-phase separator" and "filter"

references

Analysis, iron oxides in solid sediments in the incoming gas separator

(rexo,) accounted for 19.57% (excluding moisture content); sulfide

Lin Qinge. Diagnosis of rotor fouling and bearing wear of large units. Heilongjiang Petrochemical,

(Fe. 5.) accounted for 56.1%; these two items totaled 75.7%. one of them

2(XX);11(3):44

Qi Aiqin. Several measures to prevent centrifugal compressor rotor fouling and shaft vibration value increase.

Iron oxides (Fe:0,) are not all corrosion products, mostly from

Chemical Engineering Design Communications, 2(X)5;31(2):44 Yiju

For minerals, the substance usually formed on the pipe wall has a good hardness

Yang Dejun. Metal Corrosion Science. Beijing: Chemical Industry Press, 1999: 42 Talk about Tang

Fastness, only the small parts that are not well combined can be carried out.

Liu Changhai, Xue Changquan. 4RDS reciprocating compressor piping system vibration analysis and vibration reduction measures

(2) Minerals carried by incoming air: K, Na, Mg, Ca, Fe, etc.

Shi. ​​Compressor Technology, 2005; (3): 10-12

A mixture of aluminosilicate (boelite mineral) and a small amount of sulfate.

Zhao Yuhuan, Zhou Feng, Li Debin, et al. Anti-scaling measures for cracked gas compressor rotors. B

The main boolean minerals include illite, nontronite and iron saponite, and alloene industry, 1999; (3): 43-A6

Stone, etc., which contain both K, Na, Mg, Ca oxides and