Major causes of failure of chemistry in power plant

The major reason for chemistry failure in boiler is technical failure of DM plant/water chemistry in the power plant. Improper de-mineralization is the major issue for smooth operation of boiler.

 

Next we will discuss the technicalities of running a DM plant and details about the water chemistry of DM plants and power plants. But we are only talking about non technical problems which mainly affect water chemistry failure.

 

Sometimes technical errors or mistakes may occur by DM plant operators. But mostly it was found that all these mistakes are hidden even from the chemists. Chemists are responsible for testing all in-process DM plants, powering out water and delivering water to the DM transfer pump.

 

    One thing I cannot understand is that apart from the technical fault of DM plant and water chemistry, why the Operational VP or station authority was not analyzed as to why chemistry failure occurs again and again. Or deliberately don't want to look for it.

 

   Whatever I understand or feel during my working time, I am not mentioning here without any pressure or taking anyone's side, but directly telling the main reason like this.

 

1) Not owning proper DM plant and providing proper staff like managers and officers, operators. All the work of DM plant is done by external agencies and external sources. Sometimes only DM plant water chemistry, coal testing is done by out sourcing

 

3)Most DM plant incharges do not have the authority or cannot decide how many employees they require. He will be the one to decide whether the operator will appoint separately or not. In most of the places I have seen that more operators are recruited than chemists. Both the posts have different job profiles.

 

2) Nowadays most operational persons monitor online analyzers on a desk or monitor. (Since all analyzers are based on chemical dosage. SWAS also requires chemical dosage. All these chemicals require proper preparation and storage otherwise it shows another reading. Sometimes tubes with chemical dosage solution These things should also be checked offline by a chemist.

 

3) Most of the CCP operations are affected by interference of individuals in chemist testing and manipulation of results as per their wish (whatever they want). Because most of the individuals work under contractors or out sourcing and suffer from pressure to save jobs.

 

4) The next thing I am telling is very important from psychology point of view that their salary structure also affects their working style. It is very sad to mention in this material that the salary of DM Plant Head is less than that of Boiler Attendant (what do you mean by attendant, it is poin) it is very ridiculous. What will be its psychological impact on the mentality of a highly educated person?

 

5) All the employees and their salaries are decided by the operational (mechanical side) person. Which test to do, how to do it? What results to pay, how is their shift schedule, all these things are going on on the operational (mechanical side).

 

6) In most of the CPP plants only and only hourly coal testing of each vehicle is done.

 

7)To be honest, mostly they do not want to be in charge of DM plant as per their salary or qualification. According to the analysis report, they feel inferior in following whatever recommendations are made by the DM Plant. How dare we make recommendations?

 

8)  I am sad to say that sometimes the interference of operational persons is so much that they ask unbelievable questions of the chemist. Doesn't believe in the work of the chemist, told him to do the test in front of me, how to do the test, tell me the procedure, found this type of harassment most of the private power plants are running. Asking other people here and there whether this is right or not.

 

 

Hello my friends and colleagues, I am sorry to point out all these discriminations, but this fact affects the work of the team. Most individuals who are trying to resonate cannot survive in this political and discriminatory environment.

 

 

Labels: chemical, chemist, coal, DM plant, mechanical, outsource, power water, water

 

 विद्युत संयंत्र में रसायन विज्ञान की विफलता के प्रमुख कारण

बॉयलर में रसायन विज्ञान की विफलता का प्रमुख कारण बिजली संयंत्र में डीएम प्लांट/जल रसायन विज्ञान की तकनीकी विफलता है। बॉयलर के सुचारू संचालन के लिए अनुचित डी-मिनरलाइजेशन प्रमुख मुद्दा है।

आगे हम डीएम प्लांट चलाने की तकनीकी और डीएम प्लांट तथा पावर प्लांट के जल रसायन के बारे में विवरण पर चर्चा करेंगे। लेकिन हम केवल गैर तकनीकी समस्याओं के बारे में बता रहे हैं जो मुख्य रूप से जल रसायन की विफलता को प्रभावित करती हैं।

कभी-कभी डीएम प्लांट संचालकों द्वारा तकनीकी त्रुटियाँ या गलतियाँ हो सकती हैं। लेकिन ज्यादातर पाया गया कि इन सभी गलतियों को केमिस्टों से भी छुपाया जाता है। केमिस्ट सभी प्रक्रियाधीन डीएम प्लांट के परीक्षण, बिजली पानी खत्म करने और डीएम ट्रांसफर पंप तक पानी पहुंचाने के लिए जिम्मेदार होते हैं।

   एक बात मेरी समझ में नहीं आ रही कि डीएम प्लांट और वॉटर केमिस्ट्री की तकनीकी गलती के अलावा ऑपरेशनल वीपी या स्टेशन अथॉरिटी से इसका विश्लेषण क्यों नहीं कराया गया कि बार-बार केमिस्ट्री फेलियर क्यों होता है। या जानबूझकर इसकी तलाश नहीं करना चाहता.

  अपने कामकाजी समय के दौरान मैं जो कुछ भी समझता हूं या महसूस करता हूं उसका जिक्र मैं यहां बिना किसी दबाव या किसी का पक्ष लिए नहीं कर रहा हूं बल्कि सीधे तौर पर मुख्य कारण इस प्रकार बता रहा हूं।

1) उचित डीएम संयंत्र का स्वामित्व और प्रबंधकों और अधिकारियों, ऑपरेटर जैसे उचित कर्मचारी उपलब्ध नहीं कराना। डीएम संयंत्र का सारा काम बाहरी एजेंसियों और बाहरी स्रोतों द्वारा किया जाता है। कभी-कभी केवल डीएम संयंत्र जल रसायन, कोयला परीक्षण आउट सोर्सिंग द्वारा किया जाता है

3)ज्यादातर डीएम प्लांट प्रभारी के पास अधिकार नहीं है या वह यह तय नहीं कर सकते हैं कि उन्हें कितने कर्मचारियों की आवश्यकता है। ऑपरेटर अलग से नियुक्त करेगा या नहीं, यह निर्णय लेने वाला व्यक्ति होगा। ज्यादातर जगहों पर मैंने देखा है कि केमिस्ट कम ऑपरेटर की भर्ती होती है। दोनों पदों पर अलग-अलग जॉब प्रोफाइल हैं।

2) आजकल अधिकांश ऑपरेशनल व्यक्ति डेस्क या मॉनिटर पर ऑनलाइन एनालाइज़र की निगरानी करते हैं। (चूंकि सभी एनालाइज़र रासायनिक खुराक के आधार पर होते हैं। एसडब्ल्यूएएस को रासायनिक खुराक की भी आवश्यकता होती है। इन सभी रसायनों को उचित तैयारी और भंडारण की आवश्यकता होती है अन्यथा यह एक और रीडिंग दिखाता है। कभी-कभी रासायनिक खुराक सॉल्यूशन से नलिकाएं अवरुद्ध हो जाती हैं। इन चीजों की भी केमिस्ट से ऑफलाइन जांच करानी चाहिए।

3) अधिकांश सीसीपी परिचालन में व्यक्तियों के हस्तक्षेप से केमिस्ट परीक्षण और उनकी इच्छा के अनुसार परिणाम में हेरफेर भी प्रभावित होता है (जो वे चाहते हैं)। क्योंकि अधिकांश व्यक्ति ठेकेदार या आउट सोर्सिंग के तहत काम करते हैं और नौकरी बचाने के दबाव से पीड़ित होते हैं।

4) अगली बात जो मैं बता रहा हूं वह मनोविज्ञान की दृष्टि से बहुत महत्वपूर्ण है कि उनकी वेतन संरचना का भी उनकी कार्यशैली पर प्रभाव पड़ता है। इस सामग्री में यह बताना बहुत दुखद है कि डीएम प्लांट हेड का वेतन बॉयलर अटेंडेंट से भी कम है (अटेंडेंट से आपका क्या मतलब है, यह पोइन है) यह बहुत हास्यास्पद है। उच्च शिक्षित व्यक्ति की मानसिकता पर इसका मनोवैज्ञानिक प्रभाव क्या होगा।

5) सभी कर्मचारी और उनका वेतन परिचालन (मैकेनिकल पक्ष) व्यक्ति द्वारा तय किया जाता है। कौन सा टेस्ट करना है, कैसे करना है? किस परिणाम का भुगतान करना है, उनका शिफ्ट शेड्यूल कैसा है, ये सभी चीजें परिचालन (मैकेनिकल पक्ष) पर चल रही हैं।

6) अधिकांश सीपीपी प्लांट में केवल और केवल प्रत्येक वाहन के प्रत्येक घंटे का कोयला परीक्षण किया जाता है।

7)सच कहूँ तो ज्यादातर वे अपने वेतन या योग्यता के बराबर डीएम प्लांट का प्रभारी नहीं बनना चाहते हैं। विश्लेषण रिपोर्ट के अनुसार डीएम प्लांट की ओर से जो भी सिफारिश की जाती है, वे उसका पालन करने में खुद को हीन महसूस करते हैं। हमें सिफ़ारिश करने की हिम्मत कैसे हुई?

8)

     मुझे यह कहते हुए दुख हो रहा है कि कभी-कभी ऑपरेशनल व्यक्तियों का हस्तक्षेप इतना अधिक होता है कि वे केमिस्ट से अविश्वसनीय प्रश्न पूछते हैं। केमिस्ट के काम पर विश्वास नहीं करता, उससे कहा कि मेरे सामने परीक्षण करो, कैसे परीक्षण करो, मुझे प्रक्रिया बताओ, इस प्रकार का उत्पीड़न पाया गया अधिकांश निजी बिजली संयंत्र चल रहे हैं। यहां-वहां दूसरे लोगों से पूछ रहे हैं कि यह सही है या नहीं।

नमस्ते मेरे मित्र और सहकर्मी, मुझे इन सभी भेदभावों की ओर ध्यान दिलाने के लिए खेद है, लेकिन यह तथ्य टीम के काम को प्रभावित करता है। अधिकांश व्यक्ति जो प्रतिध्वनि करने का प्रयास कर रहे हैं वे इस राजनीतिक और भेदभावपूर्ण माहौल में टिक नहीं सकते हैं।

Chemical treatment for  internal problems in boilers 

 

In the boiler operation  it is very importance of protection of internal system must be smooth for smooth operation .During operation process there is happened various changes because of pressure  and temperature  ,heat ,air, dry air ,wet air ,oil and dissolved water flowing with high velocity ,having also presence of TDS and suspended matter and also other total dissolved solids .

During continuous operation metal erosion , corrosion ,scale formation by total dissolved solids takes place. These problems create abstraction in continues operation and can effect on boiler efficiency.

Internal treatment consists of adding chemicals directly to the water in boiler for removing dangerous scale forming salts which were not completely removed in the external treatment for water soften. This is mainly used as a corrective treatment to remove the slight residual hardness and also sometimes to remove the corrosive tendencies in water. This treatment is not usually applied to raw waters , except for small boiler, but it is usually practiced in large power station. In modern heavy-duty high pressure boilers, water of zero hardness is required, since even an egg shell thickness of scale may be extremely detrimental.

v  CARBONATE CONDITIONING:

 

For a salt to be precipitate sufficient amount of the ions forming the salt must be present so that the product of their concentration exceed a limiting value known as the solubility product. Thus, for a salt like CaCO3 to be precipitated, the product of the concentration of Ca+ and CO3 must exceed the solubility product of CaCO3.

When sodium carbonate solution added to the boiler water the co3 increases and when it becomes greater than KX (SO4). Only CaCO3 gets precipitate and CaSO4 remain in solution. Thus the deposition of scale forming CaSO4 is prevented.

Na2CO3+CaSO4 --------------CaCO3+Na2SO4

Carbonated conditioning is used only for low pressure boilers. In high pressure boiler the excess Na2CO3 might be converted into NaOH  due to hydrolysis as follows:

Na2CO3+H2O----------------------------2NaOH+H2CO3

H2CO3-------------H2O+CO2

NaOH Causes caustic embrittlement in high pressure boilers.

v  PHOSPHATE CONDITIONING

In this, an excess of a soluble phosphate is added to the boiler water to the precipitate the residual calcium ions in the form of a non-adherent precipitate of calcium phosphate and thus the prevent of scale formation.

The three sodium orthophosphates are using for phosphate conditioning are (Na3PO4, Na2HPO4and NaH2PO4 ) and also sodium pyrophosphate (Na4P2O2)  and sodium metaphosphate (NaPO3).the typical reaction of the various phosphates with the hardness represented as CaCO3 are given below

2Na3PO4+3CaCO3---------------------------Ca(PO4)2+3Na2CO3

2Na2HPO4+CaCO3----------------------------Ca3(PO4)2+2Na2CO3+CO2+H2o

2NaH2PO4+3caco3----------------------------------ca3(PO4)2+Na2CO3+2CO2+2H2O

2Napo4+3Caco3------------------------------------------Ca3(Po4)2+Na2CO3+2CO2

The quality of the feed water dictates the choices of the particular phosphate to be used. For instant, if the feed water tends to produce an acidic condition in the boilers, the alkaline trisodium phosphate   should be choosen. This treatment could be supplemented with NaOH if the required alkalinity could not be maintained with Na3PO4 alone.

If the feed water produce almost the right alkalinity desired in the boiler, it is preferable to use Na2HPO4 which is practically neutral.

If the boiler water becomes too alkaline, the acidic NaH2PO4 would be selected.

Both sodium pyrophosphate and metaphosphate are rapidly hydrolyzed under boiler water temperature to orthophosphates.

 

NaPO3+H2O---------------------------------NaH2PO4

Na4p2O7+H2O-------------------------- 2Na2HPO4

Thus, their behavior within the boiler is identical with that of orthophosphate mentioned above.

However NaPO3 solution are practically neutral, whereas NaH2PO4 solutions are acidic.

Hence the former could be preferred if the use of NaH2PO4 causes feedline corrosion.

The use of internal treatment combined with suitable blow-down to remove sludge has contributed largely to the operation of the modern high pressure steam boilers without the formation of hard scales.

However precautions should be taken to inspect them at least once in a six months and remove the scale and sludge accumulations.

 

v  COLLOIDAL CONDATIONING

Scale formation can be minimized by introducing into the boiler some colloidal conditioning agents such as glue, agar-agar, tannin , starches and sea-weed extract. This substances act as protective collides .They function by surrounding the minute particles of CaCo3 and CaSO4 and prevent their coalescence and coagulation thus the precipitate scale forming salts or maintained in lose suspended form which can easily be removed by blow-down operations . Thus the scale formation is prevented.

v Calogen conditioning :

Another approach for preventing scale formation is to convert the scale forming salts into highly soluble complexes which are not easily precipitated under the boiler conditions. In order to achieve this , sodium hexameta phosphate(NaPO3)6 or Na2 (Na4 P6 O18) (its trade name is calogen )is generally employed .This substance intract with the residue calcium ions forming highly soluble calcium hexameta phosphate. And thus prevents the precipitation of scale forming salts.

Na2(Na4P6O18 )     ---------------------------  2Na+ (Na4P6O18)

2Ca+(Na4P6O18 ) ------------------------------    4Na+(Ca2P6O18)

 

v Conditioning with EDTA:

Phosphate treatment fails to prevent the formation of iron oxide and cuprous deposition .sometimes, the phosphate chemicals  themselves become a sources of deposition formation. In distinction to phosphate treatment ,the conditioning of boiler water with complexing agents can secure scale free and sludge free operation of boiler units and sometimes ,also corrosion free operation under certain conditions. These reagents are known as complex ones or complexing agent such as ethylene diamine tetra acetic acid (EDTA )and its disodium salts (Na2EDTA) known as Trylon-B Or even its tetra sodium salts (Na4EDTA )

 

v  BOILER  COMPOUNDS :

Once ,during the early times of watt ‘s engine it is said that workman after cleaning the boiler and refilling with water hung a bag containing potatoes in the boiler to cook them .they forget about them and put the boiler into operation after closing it. then when the boiler was shut down again for manual removing of the scale it was found that the scale formation was much less, much of it  having come down in the form of loose sludge. The story seem to be true because for many years engineers used to through some potatoes in the boilers after every cleaning operation. Perhaps this is for runner of internal treatment of boiler salines to reduce the adherent scale formation by rendering it in the form of softer sludge which can be easily removed by blow down. slowly potatoes was replaced by starches and later by tannins and other organics and inorganic materials like soda ash and caustic soda, phosphates ,coagulant such as sodium aluminate and deoxidizer like sodium sulphate .Natural wood and plants extracts and several synthetic products have also been used.U.S.Navy was reported using a boiler compound consisting 47%  anhydrous disodium phosphate,44% soda ash and 9% starch. Castor oil compounds and various synthetics antifoam compound were also use in locomotive boilers to reduce foaming tendency. These boiler compounds do help in reducing scale formation when properly use under proper situation.