CN1769851A

CN1769851A - Method for quickly detecting leakage of heat exchanger of water circulating system in oil refinery

Info

Publication number: CN1769851A
Application number: CN 200410067963
Authority: CN
Inventors: 马竞涛; 陆文琼; 李天金
Original assignee: Sinopec Zhenhai Refining and Chemical Co Ltd
Current assignee: Sinopec Zhenhai Refining and Chemical Co Ltd
Priority date: 2004-11-04
Filing date: 2004-11-04
Publication date: 2006-05-10
Anticipated expiration: 2024-11-04
Also published as: CN100489476C

Abstract

Disclosed is a rapid leak detection method with oil refining circulating water system which comprises steps of: establishing characteristic spectrogram corresponding to media in heat exchanger of oil refining circulating water system; detecting circulating water in the system, analyzing and obtaining the analysis result spectrogram of circulating water; comparing the characteristic spectrogram with analysis result spectrogram of circulating water, detecting the characteristics of each spectrograms and finding out leaking heat exchanger or excluding part of heat exchangers. The invention has the advantages of being rapid, of avoiding pollution and effects to water quality.

Description

A kind of method for quickly detecting leakage of heat exchanger of water circulating system in oil refinery

Technical field

The present invention relates to a kind of circulating cooling water system system quick leakage detection method and technology field.

Background technology

Water cooling heat exchanger in the refinery circulation, bearing the heat exchange cooling of all process units of refinery, refining because of device long-term operation and sour crude, heat interchanger leaks because of corrosion often, in case leak, can make the recirculated water eutrophication, the COD value increases, microbial reproduction reaches and grows foundry loam in a large number, gently then, rate of water make-up cause water resource to waste in a large number because of increasing, heavy then cause other water cooling equipment corrosion in the same system, influence the heat exchange effect, bring serious potential safety hazard to production.It is a ubiquitous problem that the oil plant of circulation leaks at home in the petrochemical industry, therefore needs leakage detection as early as possible leaking when taking place, find and leak the heat interchanger that takes place so as in time to switch, repairing.

The oil content analytical approach is a lot of in the water, mainly contains: infrared spectrophotometry, its ultimate principle are the oily substances of using earlier in the extractant extraction water, and the C-H vibration that utilizes oily substance is at wave number 2800～3030CM ^-1The characteristic absorption at place, the concentration of oil is directly proportional with its light absorption value in the water.This method has accuracy preferably, has been included into national standard; Ultraviolet photometry, its principle are that aromatic compounds contained in the oil product and the material with conjugated system have characteristic absorption at ultraviolet region, and its light absorption value is directly proportional with oil concentration; The fluorescent photometry, its principle is with water PetroChina Company Limited. class extracting substances, its extract produces fluorescence under the ultraviolet ray irradiation, when oil content in the water was low, fluorescence intensity was directly proportional with oleaginousness, and this method is highly sensitive, selectivity is good, but contained fluorescent material difference during difference oil is planted, so measure when the difference of same concentrations is oily plants possible measured value difference.Gravimetric method, its principle are to extract oils with extractant from the waste water after acidifying earlier, after the extractant evaporation, take by weighing its weight, thereby record the total amount of extract in the waste water.This method complicated operation, sensitivity is low; Turbidimetry, this method principle are in immiscible water and oil body system, add a certain amount of solable matter that can water-solublely can be dissolved in oil again, form more stable opaque system, and when oil content was low, the solution turbidity size was directly proportional with oil content.It is poor that this method repeatability and accuracy are all looked into; Some instrument company has also released in-line analyzer, but these methods can only be measured the concentration of oil in the water outlet, can not record the composition of oil product in the water, can't determine the leakage which kind of oil product causes, can't find and leak the heat interchanger that takes place, with regard to the circulation that a cover is furnished with up to a hundred water cooling heat exchangers, even measured the concentration of leaking oil in the recirculated water, also be difficult to find the source (heat interchanger of leakage takes place) of leakage, still can't resolve the problem that stops leakage; Simultaneously, when taking place to leak, oil concentration is often very low in the water, needs with a large amount of organic solvent extractions, enrichment, and single analyses is chronic, and this has not only wasted valuable switching, repairing time, and a large amount of organic solvents can cause environmental pollution

Summary of the invention

Technical matters to be solved by this invention provides a kind of method for quickly detecting leakage of heat exchanger of water circulating system in oil refinery, both fast and convenient, avoided environmental pollution, shortened analysis time again, and with leaking the heat interchanger that oily feature spectrogram judges that generation is leaked, to improve leakage detection speed, find and handle the leakage of water cooler early, avoid influence to total system water quality, thereby improve the heat-transfer effect of water cooler, the consumption of conserve water consumption and material.

The present invention solves the problems of the technologies described above the technical scheme that is adopted: a kind of method for quickly detecting leakage of heat exchanger of water circulating system in oil refinery is characterized in that steps in sequence is: the heat interchanger in the circulating cooling water system system is set up the characteristic of correspondence spectrogram according to the medium in this section heat interchanger; Recirculated water to the circulating cooling water system system detects then, analyzes the analysis result spectrogram that obtains recirculated water; The analysis result spectrogram of recirculated water and the feature spectrogram of heat interchanger are compared analysis, investigate, thereby can find the heat interchanger that the heat interchanger that leaks takes place or exclude a part, dwindle the leakage detection scope according to feature spectrogram separately.

Useful is, we can adopt the result of ultraviolet photometry acquisition or the result that infrared spectrophotometry obtains, but the spectrogram that preferred gas chromatographic analysis obtains, it to the leakage oil in the recirculated water sample extract with preenrichment after, direct heat desorb in the gas chromatography injector detects the desorb thing with vapor-phase chromatography, obtain the hydrocarbon distribution plan of oil product, judge with this heat exchanger media takes place to leak is which kind of oil product (vapour, coal, bavin), and quick and convenient, economy is laborsaving.

Useful is, above-mentioned recirculated water detects the employing extraction, the preferred solid-phase microextraction method of using is as adopting the PDMS-100 solid phase micro-extracting head, the macromolecule layer of glossing over by the quartz fibre head surface extracts and preenrichment the leakage oil in the recirculated water sample, quick and convenient, economical laborsaving, avoided environmental pollution, shortened analysis time.

Useful is, above-mentioned feature spectrogram compares the carbon number range of analyzing the chromatogram characteristic that adopts n-alkane and going out the peak and judges the heat interchanger that leakage takes place, for most of heat interchanger, the hydrocarbon distribution plan of various heat exchange device medium has bigger difference, by collecting the hydrocarbon distribution plan of various heat exchange device medium, relatively leak the n-alkane chromatogram feature of oil and each heat interchanger medium, the carbon number range that goes out the peak can be judged the heat interchanger that the heat interchanger that leaks takes place or exclude a part with comparalive ease, dwindles the leakage detection scope.

Compared with prior art, the invention has the advantages that: the analytical approach of being set up is easy, quick, accurate, has favorable linearity (related coefficient is 0.9171～0.9180); Lowest detectable limit reaches 5.6～33ug/l, satisfies the requirement that the recirculated water leakage detection detects fully, and the relative deviation of replication is less than 6%, and this method can be used for petrochemical system and judges the heat exchanger media that takes place to leak is which kind of oil product (vapour, coal, bavin); And the heat interchanger that most of feature spectrograms is had obvious difference, can be by relatively leaking the n-alkane chromatogram feature of oil and each heat interchanger medium, the carbon number range that goes out the peak is judged the heat interchanger that the heat interchanger that leaks takes place or exclude a part, dwindle the leakage detection scope, avoided environmental pollution, shortened analysis time, to improve leakage detection speed, find and handle the leakage of water cooler early, avoid influence to total system water quality, thereby improve the heat-transfer effect of water cooler, the consumption of conserve water consumption and material.

Description of drawings

Fig. 1 is three normal WC106 liquid-liquid extractions and solid-phase microextraction chromatogram contrast figure;

Fig. 2 is typical vapour, coal, the contrast of bavin medium chromatogram;

Diesel oil medium chromatogram contrast in Fig. 3 various heat exchange device;

Fig. 4 is an I cover circulating water leakage oil colours spectrogram on May 30;

Fig. 5 is September 3,4 days I cover circulating water leakage oil colours spectrogram comparison.

Embodiment

Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.

Fig. 1, XHS00102.D are the chromatogram outflow figure that liquid-liquid extraction back direct injected is obtained, and HS00028.D is the chromatogram outflow figure that obtains after the solid-phase microextraction among the figure; By above 2 spectrograms contrast, can think and adopt solid-phase microextraction to carry out leaking in the recirculated water detection of oil product, its result and liquid-liquid extraction basic symbols, so the PDMS-100 solid phase micro-extracting head that SUPELCO company produces can be used for detecting recirculated water, sample is extracted, and the phase of supplying gas then chromatogram is carried out desorption analysis.

Upper, middle and lower respectively are typical vapour, coal, diesel oil medium chromatogram outflow figure among Fig. 2, relatively find, the n-alkane chromatogram distribution plan of different oil products (vapour, coal, diesel oil) has obvious difference, therefore, can be according to leaking the petroleum hydrocarbon distribution range in the recirculated water that records, leak the oil kind (vapour, coal, diesel oil) of oil in the preliminary judgement recirculated water, thereby dwindle the seek scope of leaking heat interchanger.

Fig. 3 is that the chromatogram of diesel oil medium in the different water cooling heat exchangers flows out figure, finds that majority has obvious difference, is easy to difference, but experiment also finds have part diesel oil medium spectrogram approaching, especially few in the water cooling heat exchanger leakage rate, leak in the recirculated water under the low situation of oil concentration, be difficult to clearly distinguish.

Examples of implementation 1

On May 30th, 2004, the I cover recirculated water turbidity of refinery exceeds standard, and suspects material from leakage takes place, and after having notice, the experimenter goes to collection in worksite circulation water sample at once, uses liquid-liquid extraction and solid-phase microextraction to analyze leaking sample respectively, the results are shown in Figure 4.

XHS00228.D is for being the chromatogram outflow figure that liquid-liquid extraction back direct injected is obtained among Fig. 4, and PDMS0122.D is the chromatogram outflow figure that obtains after the solid-phase microextraction; Measure nC5～nC38 standard model under similarity condition, according to retention time as can be known: the hydrocarbon distribution range that liquid-the liquid extraction records is C16～C34, mainly is distributed in C19～C29; The hydrocarbon distribution range that is recorded by solid-phase microextraction is C17～C34, mainly be distributed in C19～C29, as seen liquid-liquid extraction conforms to substantially with the measurement result of solid-phase microextraction, can judge tentatively that by carbon number distribution this time leakage may be heavier oil products such as diesel oil, wax oil.The recirculated water field of having grasped and the relation of process units see Table 3:

Table 1 recirculated water field and process units graph of a relation

The recirculated water field	Process units
The recirculated water field	Process units	I overlaps recirculated water	I is normal, old catalysis, coking, sulphur recovery (III, IV, V cover), and II is normal, I weighs hydrogenation, I, II gas branch, alkylation, MTBE
II overlaps recirculated water	Hydrocracking, hydrogen manufacturing, II reformation hydrogenation, III cover sewage stripping, industry and trade subtract slag	I overlaps recirculated water
II overlaps recirculated water		III overlaps recirculated water	The PSA air-lift device, IV hydrogenation, III reform, the aromatic hydrocarbons extracting
IV overlaps recirculated water	IV, V cover hydrogenation, II catalysis, normal, the PX device of III	III overlaps recirculated water

According to last table, search and the relevant process units water cooling heat exchanger medium chromatogram in I cover recirculated water field, relatively leak the relevant water cooling heat exchanger medium of oil colours spectrogram chromatogram with each, find that the normal decompression of I cover E116-3 medium chromatogram originally conforms to the leakage oil base, therefore judge it is that this heat interchanger leaks, after excising this heat interchanger, oleaginousness no longer rises in the recirculated water, and beginning slowly descends.

Examples of implementation 2

Above method is adopted in the leakage that September 3, the circulation of I cover took place, and finds coking cold 105 and leaks, but after heat interchanger switched, oil content was still high in the recirculated water, and everybody suspected that other heat interchanger had leaked again at that time, September 4 was continued sampling analysis, saw Fig. 5.

XHS00105 is an I cover circulating water leakage oil colours spectrogram on September 3 among Fig. 5, XHS00106 is an I cover circulating water leakage oil colours spectrogram on September 4, it is in full accord to find that relatively September 3 and 4 days are leaked the oil colours spectrogram, belong to same oil product, got rid of the possibility that other heat interchanger generation is leaked, judge by analysis,, suspection may be because during cold 105 heat exchanger leakages of coking on the 3rd, tube wall is by severe contamination, caused in the recirculated water oil concentration high, therefore carry out tube wall and clean, after the cleaning at once, oil content obviously descends in the water, has striven for the time for dealing with problems.

Certainly, present embodiment also can adopt other analytical approachs to obtain spectrogram, its ultimate principle is exactly with the dielectric attribute peak spectrogram of heat interchanger " fingerprint " as its identity, detect recirculated water then, obtain its corresponding spectrogram, analyze contrast, again according to the production process route of refinery, at least can more effectively, quickly, scientifically exclude a part of heat interchanger, usually be to confirm soon that leaking appears in a certain section heat interchanger.

The only just best embodiment of embodiments of the invention has been done full and accurate explanation; can not be interpreted as the restriction of scope that the present invention is asked for protection; every further improvement or technological means of being equal to of employing on this basis replaced, and all is protection domains of request of the present invention.

Claims

1, a kind of method for quickly detecting leakage of heat exchanger of water circulating system in oil refinery is characterized in that steps in sequence is:

A) heat interchanger in the circulating cooling water system system is set up the characteristic of correspondence spectrogram according to the medium in this section heat exchange;

B) then the recirculated water of circulating cooling water system system is detected, analyze the analysis result spectrogram that obtains recirculated water;

C) the analysis result spectrogram of recirculated water and the feature spectrogram of heat interchanger are compared analysis, investigate, thereby will find the heat interchanger of leakage or exclude the heat interchanger of a part, dwindle the leakage detection scope according to the feature on the spectrogram separately.

2, leakage detection method according to claim 1 is characterized in that the spectrogram that described spectrogram can adopt gas chromatographic analysis to obtain.

3, leakage detection method according to claim 1 is characterized in that described recirculated water detects the employing extraction.

4, leakage detection method according to claim 3 is characterized in that described extraction adopts the solid-phase microextraction method.

5, leakage detection method according to claim 4 is characterized in that described solid-phase microextraction method adopts the PDMS-100 solid phase micro-extracting head.

6, leakage detection method according to claim 1 is characterized in that described feature spectrogram compares the carbon number range of analyzing the chromatogram characteristic that adopts n-alkane and going out the peak and judges the heat interchanger that leakage takes place.