In continuation of our earlier post & video which was posted in May 2023 regarding heavy puffing oscillation & vibration in Buckstay and Front water wall of boiler......
When steam demand increases, Most of the companies think about capacity enhancement of existing Boilers OR Fuel conversion. OEM & Experts suggested a lot of proposals with high cost involvement for Boiler modification for only 10 to 15 % increment in boiler steam capacity against the rated boiler capacity.....
Selection of Boiler’s steam drum level set points for alarm and safe level trip interlock limit for failsafe operation of boiler to avoid pressure parts failure is primary responsibility of OEM & Design team for designing of adequate steam drum sizing at the time of low drum level & low-low drum level operation in boiler....
Fuel combustion in boiler i.e. Triple-T = TIME, TEMPERATURE & TURBULENCE. Normally major boiler efficiency game changer values during design calculations are predicted parameters like Unburnt Carbon Losses, Flue Gas Temperature at APH outlet, Excess Air requirement....
Any Boiler design starts with the calculation of circulation ratio based on the drum working / operating pressure. The circulation ratio is immensely important for providing safe cooling of the heated tubes. Any adjustment & efforts for cost cutting & value engineering will leave a huge impact on boiler maximum operating life....
Trouble starts with the start of a New Boiler and complete elimination is like a daydream. We need to accommodate and survive with best operational & efficiency parameters and minimum failure and downtime
Buckstay play a major role in water wall panel strengthening and control guiding of expansion movement of pressure parts in boiler. Any deficiency in buckstay design, erection & routine maintenance leave a huge impact on boiler life and cost.
Please review enclosed sheet for details commissioning inputs calculation. It will help to get the stock ready for boiler commissioning.
We have experienced a lot of basic engineering errors, their justification, then Rectification and Alteration, Later Replacement and finally Failure in the same pattern in the Coal & Biomass fired Boilers
Boiler is given guarantee of engineering/design for life span of around 25 years but trouble starts within a short time period due to engineering issues comes on surface
As a Commissioning professional, a lot of unexpected things are experienced during the Commissioning of Boiler, which are never recorded but leave behind a great impact in terms of performance, money and failures.
Minor changes in words, which are added purposefully, shall change the whole scenario in the project execution stage, when things go wrong. Later both SELLER & PURCHASER tries to save money on behalf of the terms in SIGNED CONTRACT
Failures of PRESSURE PARTS, CASING, DUCT, EQUIPMENTS due to Thermal Expansion is normally overlooked. It happened in newly commissioned boilers as well as in old established running boiler but reason is common in both the cases that is STRESS RELATED FAILURES due to “EXPANSION RESTRICTION” and “POOR FLEXIBILITY”
Bagasse GCV @50%- 2272 kcal/kg or 2300 kcal/kg a RARE Phenomena but Dominant for Bagasse Fired Boiler Design & Guaranteed Efficiency Calculation
HOW TO CHECK DESIGN IMPACT ON PERFORMANCE, (WRONG DESIGN PREDICTION lead to start JUSTIFICATION in BOILER)
We are presenting the checks for Mixed Fuel ratio Calculation & Lab analysis correction to obtain correct Boiler Performance results. Fuel Mixing Ratio (Weight Ratio OR Heat Ratio) Should be Same in Boiler Performance Test w.r.t. Design Mixing Ratio
As per my experience & knowledge, I am going to illustrate a hypothetical data on achievement of boiler performance result
Most of the time, Credit of all failures & limitations goes to faulty operation of Boiler, because We are neglecting the other important aspect. Due to non availability of technical details and concentrating only on easily identified facts to conclude the fault.
High Velocities of steam inside tubes causing less cooling of coils thus metal temperatures remain on higher side. Higher velocity of Steam, Higher pressure drop across superheater coils & Less Flow of Steam is the culprit.
Boiler’s Pressure parts along with related Machinery, Refractory, other Equipment should give effective performance individually & collectively to produce desired contractual obligations
ESP Design mainly depends on parameters like Inlet gas flow, Inlet dust concentration, Ash particle size, Ash chemical composition, Migration velocity, Electrical resistivity of fly ash & Specific Collection Area
In Tubular type APH, We rarely hear about a root cause of APH tube failure as Design Fault, while APH design is a major contributor. APH tube failures, Root Cause Analysis indicate failures only due to Dew Point Corrosion / Cold End Corrosion
Slop Fired Incineration Boiler is designed on Multi Fuel combination with individual fuel firing @100% within design boundaries. This combination of firing increase cost & design complication. Boiler should be designed on worst multi-fuel / Individual fuel condition
It is heard that Slop Fired Boiler is guaranteed to operate more than 99 days continuously without any Interruptions or Stoppage, Is it true?
Eddy current testing is a basic requirement in surface condenser & coolers as a preventive health check-up. We are submitting some technical facts to choose Eddy current testing over the routine Hydraulic testing to increase reliability and productivity of plant.
Cost effective operation of boiler with best efficiency is first priority of each & every company & it’s management and staff. Repeatability & Reproducibility are the key points for Performance Guarantee Test.
During project ordering & execution stage, most of the customers are not mentioning the specific checks & controls regarding the AFBC boiler fail safe & beneficial design. They are not exploring & recording the range of some essential velocities, temperatures & pressure drops etc, which are dominating the pressure parts and auxiliaries sizing during the design calculation of AFBC boiler
Aluminum Oxide & Silicon Carbide based Abrasive products like Grinding wheel, Mounted points of all shapes & sizes- shank type, Internal Grinding wheels, Cup Wheel - Taper & Straight, Oil Stick, Honing stick