The P&ID should clearly define what is the responsibility of each party. So for example if we are getting to build a new plant. The main feed to the plant is taken from another nearby plant, then the P&ID should clearly define the battery limit between the new plant and the line feeding it from the existing one.

If we are expanding an existing plant, then the limits between the existing plant and the new scope should be defined. That’s why there are tie-in P&IDs which show how to connect piping from the existing plant to a new plant and what the engineering company executing the new project is expected to do and what the client or the owner of the plant is expected to do.

So for example, if this valve was here, then it would be provided by the client. But if it is here, then it would be provided by the contractor, so this indicates if the contractor will consider it in his scope or it is already provided by the client or in the existing plant.

If we are purchasing a package or a skid which is a part of the process, then we are expected to define what we are expecting the package vendor to provide and what we shall purchase.

So here in this example, if the dashed line represents the scope of the vendor, then we shall buy the isolation valve, but the vendor shall consider the control valve in his package.

If these are not defined well, many conflicts may occur between different parties. People shall start to throw responsibility on each other, which may lead to many issues during the project execution.

This course lecture introduces flow elements, which are instruments used to measure fluid flow in a pipe. The most common type is the flow orifice, which determines flow rate based on pressure drop. The lecture briefly mentions that there are more complicated arrangements for flow orifices, but focuses on showing the symbol for simplicity. It mentions the presence of valves in a detailed drawing of a flow element, but notes that valves are considered when cross-checking with typical details. The lecture also mentions other types of flow elements, including rotameters, Coriolis meters, ultrasonic meters, and so on.

Let's discuss various methods of level measurement. The first method mentioned is using a local measurement with a graded level glass connected to the vessel through two connections.

Here we introduce the need for a level transmitter if the reading needs to be processed by a control system, shutdown system, or readable from a control room.

Different types of level transmitters are described, including the differential pressure level transmitter that measures the level based on the difference in static pressure, and displacement transmitters that utilize Archimedes principle. Then we shall go through guided wave radar and ultrasonic transmitters that use radar signals and sound waves to determine the liquid level. The choice of a level measurement method depends on various factors.

This lecture focuses on the stages or phases of a project and how they relate to the issuance and purpose of P&IDs (Piping and Instrumentation Diagrams). The lecturer emphasizes that the process of developing P&IDs is a long-term one that starts from the early stages of the project and continues until the construction and start-up of the plant. The main stages of the project are outlined as follows:

1. Conceptual design: At this stage, a preliminary issue of the P&ID may be considered.

2. Basic engineering: This stage involves understanding the client or operation requirements, leading to the issuance of the P&ID for review. It also includes budget estimation and ends with the issuance of the P&ID for Front End Engineering Design (FEED).

3. Detailed Engineering: This is the next significant stage where equipment and materials are purchased, and detailed activities are carried out by the piping and instrumentation team. The P&ID is issued for design at this stage.

4. Construction: As the design is finalized and data is received from vendors, HAZOP recommendations are implemented, and the P&ID is issued for construction. Piping isometrics are generated using the P&ID to facilitate construction activities.

5. Commissioning and start-up: Any modifications made during construction activities are considered, and the final as-built P&ID is issued.

The lecture indicates that each stage requires issuing and revising the P&ID to incorporate the necessary details for downstream activities. It suggests that further discussions will follow, providing more detailed information about each project stage.

When planning a tie-in point, a site visit is essential to determine the exact location. It's important to consider the hydraulic aspects, as a tie-in from a significant distance can cause a high pressure drop, affecting the flow and required pressure of the feed. The tie-in location should also be assessed from a piping perspective, considering the expected routing.

Connecting the new system to the existing running plant requires careful consideration. Depending on the circumstances, it may be necessary to shut down only the specific line being connected, isolate the entire system, or even isolate the entire plant, particularly for flare or drain systems serving the entire facility. Future connections in flare or drain headers can be easily made by closing the respective connection valve.

Alternatively, the hot tap technique can be employed to establish the tie-in connection without plant shutdown. However, this method is both dangerous and expensive, so it should only be used as a last resort when no other options are available.

While preparing the P&ID, it's important to ensure that the modification does not adversely affect the existing system, while also providing protection for the new system against any potential upset conditions. Studying the interface between the two systems and ensuring their harmonious operation is essential.

By considering these factors, a successful tie-in can be achieved, allowing for the integration of the new system into the existing plant without compromising safety or operation.

This lecture discusses packaged P&IDs, which are used when purchasing a complete unit or system from a vendor. The lecture emphasizes that the vendor is responsible for supplying the equipment, piping, and instruments within the package scope. To differentiate the vendor's scope from the plant's scope, dashed lines are commonly used in the P&IDs.

The lecture also mentions that some items may be loosely supplied by the package vendor if they affect the package performance. It highlights the importance of showing the terminal points and connections between the package and the plant's system to avoid surprises and issues during construction and start-up.

Examples of packages are provided, including crude desalters, gas dehydration units, and compressors with intercoolers or receivers. The lecture notes that the decision to consider certain units as packages or purchase their components separately depends on specific plant requirements.

In order to make sure that the plant operation is going on as expected, we need to get the information we need. This is done by placing the required instrumentation in the correct locations so that we can measure the parameters we need. This can be done through field instruments, such as pressure or temperature gauges.

Or through instruments sending indications to the DCS, the operator can read it from the control room.

And if there a parameter having an extreme value higher or lower than the allowable value, then it will send an alarm to the operator in the control room.

If we are more concerned with on-spec or off-spec products where we need to carry out tests in the laboratory, then we shall need to add sampling connections so that some fluid can be extracted through bottles to the laboratory.

Now let’s examine each one in detail.

Isolation philosophy is very important to consider while preparing the piping and instrumentation diagrams.

Based on the isolation philosophy, we shall determine where to add valves, spectacle blinds or removable spools, how to isolate different plant units or equipment so that they are safe for maintenance.

Applying proper isolation will lead to a plant that is easy to maintain. If the operator wants to go inside a vessel, dismantle a pump, remove an exchanger bundle, or get a unit out of service from a plant, then the equipment to be maintained should be totally isolated from the upstream fluid.

Otherwise, if there is some leakage or valve passing or there is no proper isolation, then the operator may be exposed to the hazard of fluid release, which may lead to a great safety issue.

Fluid release can happen due to valve or flange leakage or failure.

This shall cause loss of containment, environmental impact due to fluid spillage, and may affect the plant production, which means less profit.

The risk of fluid release would be greater if we are dealing when the fluid is under pressure, and if a great volume of fluid is expected to be released, such as being in a large vessel, or flowing in a pipe with large size.

If the fluid is hazardous, such as toxic, acidic or flammable fluids, then it would be even a safety issue that can lead to injuries, or deaths or catastrophic accidents.

Applying a proper isolation philosophy shall minimize the risk of getting the operating personnel exposed to hazardous fluids or opening/closing valves by mistake.

In addition, it shall consider a proper sectioning of the plant, so if there is an issue in a portion it can be easily isolated from the rest of the plant, which shall prevent the issue from propagation. Sectioning the plant will be explained in more detail when we talk about shutdown and blowdown.

Let's talk about different Isolation types; non proved, proved and positive isolation techniques, and the difference between single block vs double block and bleed.

So when do we choose single block vs double block and bleed, and when to use positive isolation? Let's see the main factors

This lecture highlights the importance of considering isolation, bleed valves, and bypass valves in control valve maintenance. Adding isolation valves upstream and downstream of the control valve is recommended. One or two bleed valves are required based on the fail action of the control valve. A bypass valve, with a globe valve similar in capacity to the control valve, allows for maintenance without process shutdown. An additional isolation valve can be used to prevent liquid flow downstream. These measures ensure smooth control valve operation and maintenance with minimal process disruption.

This lecture focuses on preparing operators to enter a vessel through the manhole. The process involves two key steps: emptying the vessel of liquid and ensuring a safe atmosphere inside.

To empty the vessel, the liquid level is lowered, and a drain system is utilized. A drain connection with a drain valve and spectacle blind is added to remove remaining liquid. The drain system is isolated from the process system for safety. Steam purging and washing activities are then carried out.

Water accumulated during washing, known as oily water, is drained to a segregated open drain system through another valve and spectacle blind. The open drain system is designed to handle water with residual hydrocarbons under atmospheric pressure, often located as a concrete sump below grade for gravity flow.

The valves and spectacle blinds should have appropriate flange ratings and a class break if needed. These steps ensure the vessel is evacuated, purged, and prepared for safe entry.