In a centrifugal pump, Why is the suction line diameter usually larger than the discharge line diameter?

1. To Reduce Friction Losses in Suction

a.  A larger suction pipe means slower fluid velocity.

Lower velocity = less friction loss in the pipe.

b. This helps maintain higher pressure at the pump suction.

Less friction = higher NPSHa (Net Positive Suction Head Available), which helps prevent cavitation.

2. To Maintain NPSHa Above NPSHr

a. Cavitation occurs if pressure at the suction drops below vapor pressure.

b. A large diameter reduces pressure drop, helping to keep suction pressure above vapor pressure.

c. This is especially critical in high-flow or hot fluid systems.

3. Discharge Side Can Handle Higher Pressure

a. On the discharge side, the fluid is already pressurized by the pump.

b. Higher pressure = smaller pipe can be used, and the fluid can still flow efficiently.

c. Slightly higher velocity on discharge is acceptable (and sometimes even desirable)

Isometric drawings of pipes

Isometric piping diagrams are isometric representation of a single pipeline in the factory. It's the most important output of pipeline engineering department. Pipe manufacturing work depends on isometric drawings.

The isometric diagram of pipes consists of three sections. The main section consists of isometric representation of the pipeline path in 3D space, and includes the following information:

1. The line number.

2. The direction of the flow

3. Poster signs and props.

4. Site of pipe components.

5. Welding sites.

The section to the left or right of the drawing includes a material list section for the portion of the line that appears in the isometric drawing. This section includes the following information for all components:

1. Describing the ingredients.

2. The ingredient code.

3. Nominal size.

4. Quantity.

5. Whether material for manufacturing shop or field work.

6. The number of pieces.

The title bar section at the bottom includes the following information:

1. Project details such as client name, engineering office name, project name, project number, project processor license, etc.

2. Pipeline details such as line number, line size, isolation, tracing, liquid code, operating and design pressure and temperature, pressure testing method such as hydraulic or aeronautical test, test pressure, pipe material category, inch diameter, etc.

Accounts:

Inch Meter = Length of pipes in meter x Size of pipes in inch

Inch Dia = size of pipes in inch x number of connections

Isometric Diagram Checklist:

The isometric diagram should be checked according to the project's isometric diagram checklist. This list includes general points as well as project-specific points.

Symbols of Isometric Graphics

Description: Link of codes

Project-specific instructions for testing isometers: Each project has its own requirements. These requirements should be reflected in isometric diagrams. Some of these requirements may relate to:

1. Pressure Safety Valves

Screw Supply Range (Input/Output)

Bolts and bolts in the line, inlet or exit.

2. Fire fighting lines

Pipe cutting requirements.

Types of edges (flat edge or high edge).

3. Ventilation and practical drainage

Ventilation and drainage requirements for hydraulic testing.

Direct distance requirements for flow meters.

4. Insulation of pipes

Isolation fish and its range.

5. Selection of valves / alignment

6. Requirements of jack score rim.

7. Identification of the Pros.

8. The requirements of connections / lovers.

9. Dimensions of galvanized pipe cutting.

10. Signs of the rooster crowing.

11. Notes of mounting props.

12. Channeling the rim of the Orivice.

13. Sequence of delivery in PID layout

14. Edges/fills and bolts at the end of iso sheet.

15. Philosophy of disconnection of paper.

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The professional post:

🔧 Everything you need to know about pipe isometric drawings! 🛠️

Isometric drawings are an essential component in the design and execution of piping in industrial projects. In these graphs, you can find everything about the pipeline, from line number to welding locations and props. These drawings are the document on which the piping department relies on to carry out the work accurately and professionally.

💡 What the isometric diagrams include:

1. Basic information such as line number, flow direction, and pipe supports.

2. Detailed information such as details of materials, sizes and quantities.

3. Tests and methods of testing pressure like hydraulic or aeronautical.

4. Special project requirements such as safety valves, isolation requirements and isometric graph codes.

📊 Special project modifications include:

Safety valves

Fire fighting lines

The requirements of isolation

Steering the edges

Requirements of Rolled Edges

𝐖𝐞𝐥𝐝𝐢𝐧𝐠 𝐃𝐞𝐟𝐞𝐜𝐭𝐬: 𝐀 𝐐𝐮𝐢𝐜𝐤 𝐆𝐮𝐢𝐝𝐞 𝐟𝐨𝐫 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐬 𝐚𝐧𝐝 𝐖𝐞𝐥𝐝𝐞𝐫𝐬

Welding is a critical process in fabrication, but it's not without its challenges. Understanding common welding defects is essential for ensuring strong, reliable joints and maintaining structural integrity. Here's a quick look at 8 frequent welding defects every welder and engineer should be aware of:

𝟏. 𝐂𝐫𝐚𝐜𝐤

 Cracks are serious defects that weaken the weld and can propagate under stress, often caused by rapid cooling or high residual stresses.

𝟐. 𝐏𝐨𝐫𝐨𝐬𝐢𝐭𝐲

 Porosity appears as gas pockets or voids within the weld, usually due to contamination or improper shielding gas during welding.

𝟑. 𝐔𝐧𝐝𝐞𝐫𝐜𝐮𝐭

 Undercut occurs when the weld metal fails to fill the groove between the base metals, leaving a groove along the weld toe, reducing strength.

𝟒. 𝐂𝐨𝐥𝐥𝐚𝐩𝐬𝐞

 Collapse is a structural failure where the weld loses its profile due to excessive heat input or poor joint design.

𝟓. 𝐒𝐩𝐚𝐭𝐭𝐞𝐫

 Spatter consists of small metal droplets scattered around the weld area, often caused by high current or incorrect arc length.

𝟔. 𝐎𝐱𝐢𝐝𝐚𝐭𝐢𝐨𝐧 𝐁𝐥𝐚𝐜𝐤𝐞𝐧𝐢𝐧𝐠

 This defect results from exposure to air during welding, leading to discoloration and a weakened weld zone due to oxidation.

𝟕. 𝐁𝐮𝐫𝐧𝐢𝐧𝐠-𝐓𝐡𝐫𝐨𝐮𝐠𝐡

 Burn-through occurs when the base metal melts away, creating holes—often due to excessive heat or thin base material.

𝟖. 𝐏𝐨𝐫 𝐅𝐨𝐫𝐦𝐢𝐧𝐠

 Poor forming refers to improper weld shape or bead formation, affecting both aesthetics and strength of the joint.

📌 Ensuring proper technique, parameters, and joint preparation is key to avoiding these defects and achieving high-quality welds.

 Let’s keep building better, safer structures—one weld at a time

Why suction piping diameter is bigger than discharge in centrifugal pump❓

👉 In the world of fluid dynamics and mechanical engineering, centrifugal pumps play a crucial role in transporting liquids from one place to another. A key aspect of their design and operation is the sizing of the suction and discharge piping. Typically, the suction piping of a centrifugal pump is larger in diameter than the discharge piping. This design choice is not arbitrary but is based on several important principles of physics and engineering. Let's delve into why suction piping diameter is often bigger than the discharge piping in centrifugal pumps.

👉 Understanding Centrifugal Pumps
First, it's essential to understand how a centrifugal pump works. A centrifugal pump uses an impeller to add velocity to a liquid, which is then converted into flow. The liquid enters the pump through the suction inlet, where it is accelerated by the impeller and then discharged through the outlet. The efficiency and effectiveness of this process depend significantly on the design and sizing of the pump and its associated piping.

👉 The Role of Suction Piping
The suction piping is responsible for delivering the liquid to the pump. The primary goal here is to ensure that the liquid reaches the pump with minimal resistance and without causing cavitation, which is the formation of vapor cavities in a liquid due to low pressure. Cavitation can cause significant damage to the pump and reduce its efficiency.

👉 Why Larger Suction Piping?
1️⃣ Reducing Friction Losses: A larger diameter pipe results in lower fluid velocity, which in turn reduces friction losses. Lower friction losses mean that the liquid can flow more easily into the pump, reducing the energy required to move the liquid and minimizing the risk of cavitation.

2️⃣ Minimizing Pressure Drop: As liquid flows through a pipe, there is a natural drop in pressure due to friction and other factors. A larger diameter pipe helps to minimize this pressure drop, ensuring that the liquid reaches the pump at a higher pressure. This is crucial for maintaining the Net Positive Suction Head (NPSH), which is the difference between the pressure at the suction inlet and the vapor pressure of the liquid. Adequate NPSH is essential for preventing cavitation.

3️⃣ Enhancing Pump Efficiency: By reducing friction losses and minimizing pressure drop, a larger suction piping diameter helps to enhance the overall efficiency of the pump. This means that the pump can operate more effectively, with less energy consumption and reduced wear and tear.

4️⃣ Handling Viscous Liquids: When dealing with viscous liquids, which have a higher resistance to flow, a larger suction piping diameter becomes even more important. The increased diameter helps to accommodate the higher resistance and ensures smooth flow into the pump.

👉 The Role of Discharge Piping
The discharge piping, on the other hand, is responsible for transporting the liquid from the pump to its destination. The primary goal here is to deliver the liquid at the desired flow rate and pressure. A smaller diameter pipe is often used for discharge piping because it helps to maintain higher fluid velocity and pressure, which are essential for effective transportation and distribution of the liquid.

Pipe Welding Sites and Techniques - For Quality Control Engineers (QC)

In piping industry, welding is not only a manual skill, but a science and technology based on strict international standards.

🔍QC engineer responsible for inspecting welds and ensuring that they comply with codes such as ASME Section IX and AWS D1.1.1.

📌 Welding Positions:

🔧 These locations have been designated to ensure welders are tested in various conditions.

1. 1G - Flat Position:

🔹 The pipe is placed horizontal

🔹 A welder is only welding from above

2. 2G - Horizontal Position:

🔹 The pipe is in a vertical position

🔹 Welding is done horizontally on the side wall

3. 5G - Horizontal Fixed):

🔹 The tube is horizontal but cannot be rotated

🔹The welder works on the tube perimeter from bottom to top

4. 6G - Inclined at 45° and steady angle:

🔹 The pipe is fixed at a 45° angle and cannot be rotated

Welding works from all directions🔹

⚠️ The most difficult site, and is used to test the competence of welders because it mimics all situations.

5. 6GR - 6G with Restricted:

🔹 Like 6G but with obstacles that prevent the welding from moving freely.

🔹 Used in very critical work, such as ship structures or complex systems

🧠 Needs a very professional welder.

⚙️ Welding Techniques Used in Pipes (WP):

Each technique has its properties, and its selection depends on the type of material, tube thickness, and welding location (workshop or site).

1. SMAW (Shielded Metal Arc Welding)

🔸 Widely used in welding carbon steel pipes

🔸 Flexible and works well in outdoor sites

🔸 Suitable for difficult positions such as 5G and 6G.

2. GTAW (TIG – Tungsten Inert Gas):

🔸 Especially used in root passes (Root Pass)

🔸 Ideal for stainless steel (Stainless Steel)

🔸 Gives accurate and clean welders

🔸 It requires high skill.

3. FCAW (Flux Cored Arc Welding) / GMAW (MIG):

🔸 Used in workshops and factories

🔸 Provides high productivity

🔸 Less common in operation pipes due to the need to protect against gases and conditions.

Welding Procedure - WPS/ PQR According to ASME Section IX 

🔸 WPS (Welding Procedure Specification):

A document that shows the method of welding in detail (matter, position, electrode type, temperature, welding speed... Etc).

🔸 PQR (Procedure Qualification Record):

Demonstration documentation of WPS welding test results, includes mechanical, visual and non-destructive inspections.

Important tips for QC quality control engineers:

🔹 Always check the validity of your WPS documents - is it 5G or 6G mode?

🔹Watch the compatibility of Filler Metal with the basic metal

🔹Check the quality of the root pass accurately - it is the basis of good restraint

🔹 Do not forget to check the temperature preheat (Preheat) and post-weld Heat Treatment – PWHT) if found.

Nox Emissions and their Impact

Emissions of oxides of nitrogen, commonly referred collectively as NOx, are regulated because of their adverse effects on health and the environment. They play an important role in acid rain, the formation of harmful ozone and photochemical smog in the lower atmosphere and the depletion of the beneficial ozone in the upper atmosphere.

The most environmentally important oxides of nitrogen are:

NO, NO2, and, more recently, N2O.

N2O is a recent concern because it is a "greenhouse" gas which contributes to global warming and because it can aid in destroying the upper atmosphere ozone layer which protects us from ultraviolet radiation. Fortunately, very little N2O is emitted from the flame of a typical burner.

Over 90% of the NOx from a typical flame is in the form of NO and the remainder is NO2. However, since NO is eventually converted to NO2 in the atmosphere, most regulations treat all of the NOx as NO2.

NOx emissions from combustion sources are due to the oxidation of atmospheric N2 and the oxidation of nitrogen chemically bound in fuel molecules. Mechanisms for forming NO include the fuel NOx, prompt NOx and thermal NOx mechanisms. Some of these mechanisms are well understood, while others are still under investigation.

Although NO and NO2 molecules last only a matter of days in the atmosphere, N2O is a very stable species that can last 100 to 200 years in the lower atmosphere. Because of its long life span some N2O eventually reaches the upper atmosphere where it decomposes under ultra violet light and it's reaction products efficiently remove ozone from the upper atmosphere.

Processes of the Rankine cycle

 The Rankine cycle is a thermodynamic cycle which converts heat into work. The heat is supplied externally to a closed loop, which usually uses water as the working fluid. This cycle generates about 80% of all electric power used throughout the world. including It is named after William John Rankine, a Scottish scientist.

A Rankine cycle describes a model of the operation of steam Turbine most commonly found in Industrial Power Plants. Common heat sources for power plants using the Rankine cycle are Coal, Natural Gas ot Liquid Fuels.

The Rankine cycle is sometimes referred to as a practical Carnot Cycles, when an efficient turbine is used, the TS diagram will begin to resemble the Carnot cycle. The main difference is that a pump is used to pressurize liquid instead of gas. This requires about 100 times less energy than that compressing a gas in a compressor. (as in the Carnot Cycle).

The efficiency of a Rankine cycle is usually limited by the working fluid. Without the pressure going super critical the temperature range the cycle can operate over is quite small, turbine entry temperatures are typically 565°C (the creep limit of stainless steel) and condenser temperatures are around 30°C. This gives a theoretical Carnot efficiencyof around 63% compared with an actual efficiency of 42% for a modern coal-fired power station.

The working fluid in a Rankine cycle follows a closed loop and is re-used constantly. The water vaporoften seen billowing from power stations is generated by the cooling systems (not from the closed loop Rankine power cycle) and represents the waste heat that could not be converted to useful work. Note that steam is invisible until it comes in contact with cool, saturated air, at which point it condenses and forms the white billowy clouds seen leaving cooling tower. While many substances could be used in the Rankine cycle, water is usually the fluid of choice due to its favorable properties, such as nontoxic and unreactive chemistry, abundance, and low cost, as well as its thermodynamic properties.

One of the principal advantages it holds over other cycles is that during the compression stage relatively little work is required to drive the pump, due to the working fluid being in its liquid phase at this point. By condensing the fluid to liquid, the work required by the pump will only consume approximately 1% to 3% of the turbine power and so give a much higher efficiency for a real cycle. 

Ts diagram of a typical Rankine cycle operating between pressures of 0.06bar and 50bar

There are four processes in the Rankine cycle, each changing the state of the working fluid. These states are identified by number in the diagram to the right.

• Process 1-2: The working fluid is pumped from low to high pressure, as the fluid is a liquid at this stage the pump requires little input energy.
• Process 2-3: The high pressure liquid enters a boiler where it is heated at constant pressure by an external heat source to become a dry saturated vapor.
• Process 3-4: The dry saturated vapor expands through a turbine, generating power. This decreases the temperature and pressure of the vapor, and some condensation may occur.
• Process 4-1: The wet vapor then enters a condenser where it is condensed at a constant pressure and temperature to become a saturated liquid. The pressure and temperature of the condenser is fixed by the temperature of the cooling coils as the fluid is undergoing a phase change.

In an ideal Rankine cycle the pump and turbine would be isentropic, i.e., the pump and turbine would generate no entropy and hence maximize the net work output. Processes 1-2 and 3-4 would be represented by vertical lines on the Ts diagram and more closely resemble that of the Carnot cycle. The Rankine cycle shown here prevents the vapor ending up in the superheat region after the expansion in the turbine, which reduces the energy removed by the condensers.

Real Rankine cycle (non-ideal)

Rankine cycle with superheat

In a real Rankine cycle, the compression by the pump and the expansion in the turbine are not isentropic. In other words, these processes are non-reversible and entropy is increased during the two processes. This somewhat increases the power required by the pump and decreases the power generated by the turbine.

In particular the efficiency of the steam turbine will be limited by water droplet formation. As the water condenses, water droplets hit the turbine blades at high speed causing pitting and erosion, gradually decreasing the life of turbine blades and efficiency of the turbine. The easiest way to overcome this problem is by superheating the steam. On the Ts diagram above, state 3 is above a two phase region of steam and water so after expansion the steam will be very wet. By superheating, state 3 will move to the right of the diagram and hence produce a dryer steam after expansion.

Introduction to Steam turbine

 A rotor of a modern steam turbine

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion.

Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about 80% of all electricity generation in the world is by use of steam turbines. The steam turbine is a form of heat engine that derives much of its improvement in thermomodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process..

 Types

Industrial steam turbines employ both impulse and reaction. Their capacities vary from 0.5 MW to 1000 MW.

 Steam Supply and Exhaust Conditions

These types include condensing, non condensing, reheat, extraction and induction.

process steam are available.

Condensing turbines are most commonly found in electrical power plants. These turbines exhaust steam in a partially condensed state, typically of a quality near 90%, at a pressure well below atmospheric to a condenser.

Reheat turbines are also used almost exclusively in electrical power plants. In a reheat turbine, steam flow exits from a high pressure section of the turbine and is returned to the boiler where additional superheat is added. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion.

Extracting type turbines are common in all applications. In an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sent to boiler feedwater heaters to improve overall cycle efficiency. Extraction flows may be controlled with a valve, or left uncontrolled. Induction turbines introduce low pressure steam at an intermediate stage to produce additional power.

Casing or Shaft Arrangements

These arrangements include single casing, tandem compound and cross compound turbines. Single casing units are the most basic style where a single casing and shaft are coupled to a generator. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A cross compound turbine is typically used for many large applications.

Principle of Operation and Design

An ideal steam turbine is considered to be an isentropic process, or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. No steam turbine is truly “isentropic”, however, with typical isentropic efficiencies ranging from 20%-90% based on the application of the turbine. The interior of a turbine comprises several sets of blades, or “buckets” as they are more commonly referred to. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

Schematic diagram outlining the difference between an impulse and a reaction turbine

To maximize turbine efficiency, the steam is expanded, generating work, in a number of stages. These stages are characterized by how the energy is extracted from them and are known as impulse or reaction turbines. Most modern steam turbines are a combination of the reaction and impulse design. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type.

Impulse Turbines

An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage.

As the steam flows through the nozzle its pressure falls from steam chest pressure to condenser pressure (or atmosphere pressure). Due to this relatively higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity. The steam leaving the moving blades is a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit velocity is commonly called the "carry over velocity" or "leaving loss".

Reaction Turbines

In the reaction turbine, the rotor blades themselves are arranged to form convergent nozzles. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor.

Speed regulation

The control of a turbine with a governor is essential, as turbines need to be run up slowly, to prevent damage while some applications (such as the generation of alternating current electricity) require precise speed control. Uncontrolled acceleration of the turbine rotor can lead to an overspeed trip, which causes the nozzle valves that control the flow of steam to the turbine to close. If this fails then the turbine may continue accelerating until it breaks apart, often spectacularly. Turbines are expensive to make, requiring precision manufacture and special quality materials.

MARINE ENGINEERING BOOKS LIST

 

      1.REEDS NAVAL ARCHITECTURE FOR MARINE ENGINEERS

 VOL-4    BY E.A.STOKE

      2. REEDS MOTOR ENGINEERING KNOWLEDGE VOL-7

3.REEDS SHIP CONSTRUCTION VOL-5

4.REEDS BASIC ELECTRO TECHNOLOGY VOL-6

5.REEDS ADVANCED ELECTRO TECHNOLOGY VOL-7

6.REEDS GENERAL ENGINEERING KNOWLEDGE FOR MARINE ENGINEERS VOL-8

7.LAMBS QUESTIONS AND ANSWER ON THE MARINE DIESEL ENGINE BY STANLEY  G.CHRISTENSEN

8.MARINE AUXILLARY MACHINERY BY H.D. MC GEORGE

9.DIESEL MOTOR SHIPS ENGINES AND MACHINERY TEXT BY CHRISTEN KNAK

10.DIESEL MOTOR SHIPS ENGINES AND MACHINERY DIAGRAMS BY CHRISTEN KNAK

11.MARINE ENGINEERING KNOWLEDGE FOR JUNIOR ENGINEERS BY NANDA AND GOKHALE

12.PUPM OPERATION AND MAINTENANCE BY TYLER G.HICKS,BME

13.MARINE DIESEL ENGINES BY D.K.SANYAL

14.MARINE BOILERS BY G.T.H.FLANAGAN,C ENG.FLMARE,MARINA

15.FEED WATER SYSTEMS AND TREATMENT BY G.T.H.FLANAGAN,C ENG.FLMARE,MARINA

16.MERCHANT SHIP CONSTRUCTION BY D.A.TAYLOR

17.INTRODUCTION TO MARINE ENGINEERING BY D.A.TAYLOR

18.POUNDERS MARINE DIESEL ENGINES BY DOUGH WOODYARD

19.ELECTRICITY APPLIED TO MARINE ENGINEERING BY W.LAWS

20.MARINE ELECTRICAL EQUIPMENT AND PRACTICAL BY MC GEORGE II.D.

21.DICTIONARY OF MARINE TECHNOLOGY.

22.PRACTICAL MARINE ELECTRICAL KNOWLEDGE BY DENNIS T.HALL

23.THE RUNNING AND MAINTENANCE OF MARINE MACHINERY  BY J.COWLEY

Fuel NOx and Prompt NOx

Fuel NOx is produced if nitrogen is chemically bound in the fuel molecule and is primarily a concern with heavy oils and solid fuels. Some gaseous fuels, however, can contain NH3, HCN or amine carry-over as potential sources of fuel bound nitrogen. For fuels with organically bound

nitrogen, the fuel NOx mechanism begins with the decomposition of the organic molecule in the flame zone:

CxHyN → Cx-1Hy-1 + HCN

or CxHyN → CxHy-1 + NH,

depending on the nature of the carbon/hydrogen/nitrogen bonds. The HCN or NH reacts further and may be oxidized to NO.

Prompt NOx is the NOx formed from N2 in the very early portion of the flame zone where the fuel and air are first reacting. It is formed in a part of the flame where little, if any thermal NOx should be formed and, by definition, is that NOx formed from molecular nitrogen which is in

excess of the NOx predicted by the thermal NOx mechanism. There are several reaction paths postulated for forming prompt NOx. One of the more important involves the reaction of molecular nitrogen with hydrocarbon radicals formed during the decomposition of the fuel in the

initial reaction zone. The major reactions are:

CH + N2 ↔ HCN + N,

and C + N2 ↔ CN + N.

The fuel NOx and prompt NOx mechanisms proceed identically after these initiation reactions.

NOx CONTROL

The major contributors to NOx emissions are thermal NOx and, if fuel bound nitrogen is present, fuel NOx. Most refinery process heaters in the US are fueled by refinery fuel gas and, thus, thermal NOx is the primary concern. As noted previously, thermal NOx is strongly influenced by peak flame temperatures and the key to controlling thermal NOx is to moderate peak flame temperatures.

Historically, thermal NOx control techniques have included excess air control, air or fuel combustion staging and flue gas recirculation. Low excess air operation provides only limited benefit. However, it is compatible with, and can be used together with, most of the other NOx control techniques. Combustion staging and flue gas recirculation have proven to be more beneficial. The combination of fuel staging and flue gas recirculation has proven to be the most beneficial combination until recent developments. Low NOx industrial burners have been developed utilizing these NOx control techniques

Thermochemical & Electrolysis technologies - Hydrogen Production

Thermochemical & Electrolysis technologies - Hydrogen Production

Hydrogen is often produced through thermochemical processes, which heat to separate hydrogen from its source.

● Natural Gas Reforming

About 95% of the hydrogen produced in the world today is created through steam methane reforming. In this process, high-temperature steam and heat are used to separate hydrogen from a methane source, usually natural gas. An alternative method, called partial oxidation, reacts with methane and other hydrocarbons found in natural gas with oxygen to produce synthesis gas, from which hydrogen can be separated.

● Gasification

Gasification involves applying heat, pressure, and steam to convert coal or biomass into a gaseous mixture of hydrogen, carbon monoxide, carbon dioxide, and other compounds.

Absorbers then separate the hydrogen from the gas mix.

● Renewable Liquid Fuel Reforming

Like natural gas reforming, renewable liquid fuel reforming uses high-temperature steam to

create a gaseous mixture of hydrogen and carbon monoxide. In this case, however, the source

is a renewable fuel such as bio-oil or ethanol.

Electrolytic Hydrogen Production

○ Electrolytic hydrogen production methods use electricity to split water (H2O) into hydrogen (H2) and oxygen (O). When the process is reversed, hydrogen and oxygen are combined to produce electricity and water.

When and how did air separation start?

 In May 1895, Carl von Linde performed an experiment in his laboratory in Munich that led to his invention of the first continuous process for the liquefaction of air based on the Joule-Thomson refrigeration effect and the principle of countercurrent heat exchange. This marked the breakthrough for cryogenic air separation.

For his experiment, air was compressed from 20 bar [p₁] [t₄] to 60 bar [p₂] [t₅] in the compressor and cooled in the water cooler to ambient temperature [t₁]. The precooledair was fed into the countercurrent heat exchanger, further cooled down [t₂] and expanded in the expansion valve (Joule-Thomson valve) [p₁] to liquefaction temperature [t₃]. The gaseous content of the air was then warmed up again [t₄] in the heat exchanger and fed into the suction side of the compressor [p₁]. The hourly yield from this experiment was approx. three litres of liquid air. Linde based his experiment on findings discovered by J. P. Joule and W. Thomson (1852). They found that compressed air expanded in a valve cooled down by approx. 0.25°C with each bar of pressure drop. This proved that real gases do not follow the Boyle-Mariotte principle, according to which no temperature decrease is to be expected from expansion. An explanation for this effect was given by J. K. van der Waals (1873), who discovered that the molecules in compressed gases are no longer freely movable and the interaction among them leads to a temperature decrease after decompression.

Why Line Blinding?

 Typical circumstances requiring absolute shutoff include:

• Protection of the health and safety of personnel

• Avoidance of product contamination

• Control of products flowing through manifolds or common pipelines

It is well recognized that many conventional types of valves may develop leaks. Causes of leaks include age, misuse, erosion and distortion.  These valves cannot be guaranteed to provide absolute shutoff in the line. Therefore, it is necessary to close off or blind the pipeline by other means.

Advantages of Line Blind Valves

 Where blinding is a frequent requirement and safety is of primary concern,Line Blind Valves are essential.

• Positive, permanent shutoff

When the blank end of the spectacle plate is clamped in position, product cannot leak to the downstream side of the line.

• Visible shutoff

The reverse end of the spectacle plate is visible outside the valve body, providing a positive visual indication of its open or closed position.

• Fast, one person operation

Only one person is needed to operate most Hamer Line Blind Valves. Blinding takes only a few minutes with an operating bar and substantially reduces operating time and cost. Other methods generally take two to four pipefitters (depending on pipe size) 30 to 45 minutes for blinding a line.

• Complete range

The widest range of line blind valves is available for varied applications and includes models with enclosed spectacle plate chambers to prevent spillage in case the line was not totally drained when the spectacle plate is reversed.

• Long service life

Experience proves it. Hamer Line Blind Valves provide long, trouble-free service.

A small wind electric system will work for you if:

 A small wind electric system will work for you if:

• There is enough wind where you live

• Tall towers are allowed in your neighborhood or rural area
• You have enough space
• You can determine how much electricity you need or want to produce
• It works for you economically.

How Do Wind Turbines Work?

Wind is created by the unequal heating of the Earth’s surface by the sun.Wind turbines convert the kinetic energy in wind into mechanical power that runs a generator to produce clean electricity. Today’s turbines are versatile modular sources of electricity. Their blades are aerodynamically designed to capture the maximum energy from the wind. The wind turns the blades, which spin a shaft connected to a generator that makes electricity.

the ambient noise level of most modern residential wind turbines is around 52 to 55 decibels.

The smaller or “micro” (20- to 500-watt) turbines are used in a variety of applications such
as charging batteries for recreational vehicles and sailboats.

One- to 10-kW turbines can be used in applications such as pumping water

A typical home uses approximately 10,000 kilowatt-hours (kWh) of electricity per year (about 830 kWh per month). Depending on the average wind speed in the area, a wind turbine rated in the range of 5 to 15 kW would be required to make a significant contribution to this demand. A 1.5- kW wind turbine will meet the needs of a home requiring 300 kWh per month in a location with a 14- mile-per-hour (6.26-meters-per-second) annual average wind speed.

Automatic overspeed-governing systems to keep the rotor from spinning out of control in very high winds.

The amount of power a turbine will produce is determined primarily by the diameter of its rotor. The diameter of the rotor defines its “swept area,” or the quantity of wind intercepted by the turbine.

A general rule of thumb is to install a wind turbine on a tower with the bottom of the rotor blades at least 30 feet (9 meters) above any obstacle that is within 300 feet (90 meters) of the tower.

to raise a 10-kW generator from a 60-foot tower height to a 100-foot tower involves a 10%
increase in overall system cost, but it can produce 29% more power.

Price Reporting Agencies

 Majorly there were four Price Reporting Agencies (PRA) in the World namely

·         Platts,

·         Argus Media,

·         Asia Petroleum Price Index (APPI), and

·         ICIS London Oil Report

 

Price Reporting Agencies (PRA)	Methods of reporting data
ICIS London Oil Report	subjective approach based on the first-hand extensive trading experience of its reporters
APPI	mechanical approach based on data submitted in writing to an accounting firm by a panel of traders
Platts	combination of mechanistic analysis and judgement
Argus Media	combination of mechanistic analysis and judgement

 

Averaged over lengthy time periods, the differences among prices reported by different PRAs for the same crude oil grade is usually substantially less than $1.00/bbl.

In the case of the key benchmark grade of “Dated Brent” this difference is about $0.01/bbl.

In the case of other benchmarks, such as Dubai and Tapis, the differences over time can be more substantial.

ICIS which employs the ICE one-minute marker directly for the purpose of establishing its 21-Day BFOE assessment

Platts prices are perceived to be firmly entrenched in the contractual fabric of the industry and it and has the largest customer base followed by Argus. There is considerable inertia in the industry that sees even companies that are highly critical of Platts and its methodologies continuing to use it as a price reference source in their deals.

Latest Technologies in the field of Mechanical Engineeering

 

• 3D Printing (Additive Manufacturing)
• Interconnected Machines
• Internet of Things
• Industry 4.0
• Digital Manufacturing
• Bio-Medical Engineering
• Green Manufacturing
• Nano-Technology
• Alternative Energy (Solar energy and Other Renewable energies)
• Mechatronics
• Robotics
• Smart Materials/Composites
• Automation and Intelligent System
• CAD CAM Sustainability
• Agricultural Technology (Equipment used in Agriculture)
• Energy Solutions
• Textile Industry
• Self Driving Cars and New Automated Transport solutions
• Manufacturing Optimization
• Rapid Tooling
• Project Management
• Laser Cooling
• Cryogenics
• 4D Printing Technology
• Nano Electro-Mechanical Systems
• Digital Twins
• Hyperloop Technology
• Computational Fluid Dynamics
• IIOT (Industrial Internet of Things)
• Beamed Energy Propulsion
• Autonomous Vehicle
• A scramjet (Supersonic Combustion Ramjet)
• Fuel-Efficient Engine Technologies
• High-Speed Machining
• Advances in Gas Turbine Technology
• Stir Friction Welding
• Agile Manufacturing
• Advances in Heating, Ventilation and Air Conditioning.

Deming’s 14 Points for Management

 

1. Create constancy of purpose towards improvement of product and service with aim to be competitive, stay in business and provide jobs.
2. Adopt a new philosophy – new economic age, learn responsibilities and take on leadership for future change.
3. Cease dependence on inspection to achieve quality. Eliminate the need for inspection on a mass basis by building quality into product in the first palace.
4. End the practice of awarding business on the basis of price, instead, minimize total costs.
5. Improve constantly and forever the system of production and service, to improve quality and productivity, thus decreasing costs.
6. Institute training on the job
7. Institute leadership, supervision to help do a better job.
8. Drive out fear, everyone can work effectively for company.
9. Breakdown barriers between departments. Work as teams to foresee production problems.
10. Eliminate slogans, exhortations, and targets for workforce.
11. Eliminate numerical quotas on the workforce.
12. Remove barriers that rob people pride of workmanship.
13. Institute a vigorous program of education and self-improvement.
14. Put everybody to work to accomplish the transformation.