SAJJAD KHUDHUR ABBASCeo , Founder & Head of SHacademyChemical Engineering , Al-Muthanna University, IraqOil & Gas Safety and Health Professional – OSHACADEMYTrainer of Trainers (TOT) - Canadian Center of Human Development

Episode 31 : Project Execution Part (2)

E/MC TechnologyE/MC technology = The Electrical

Engineering and Measurement, Control and Regulation Technology

E/MC is subdivided into three fields:• electrical engineering• measurement engineering• control engineering

Electrical engineering comprises energy supply, controlcabinets and the cabling of the electrical consumers.

Measurement engineering comprises measuring instruments release their signals to the host computer, host computer convert it into the relevant control signals, control signals run to the control cabinets via remote bus system and trigger off the activities of the motors.

In control engineering, the control computers are connected to the process control station in the control room via a redundant communication bus system.

Electrical Engineering

• Modern switching stations are designed with plug – in systems• For each electrical consumer of the plant a separate plug – in module with the electric

elements required for each consumer is provided.• Process engineer ’ s task is the compilation of the E ‐ consumer list.• At first, the lists contain only designations like device number and plain text.• Then the lists have to be completed with information about power input, kind and level of

voltage as well as the starting current.• With the aid of this information, E ‐ engineer can determine the suitable cross ‐

sectional area of the cable and plug ‐ in modules for the switching cabinets.• From the number and kind of plug ‐ in modules the number and size of the switching

cabinets will result and thus the required space needed for the whole switching station.

Measurement Engineering

• At first, all measuring points of the plant have to be listed.• The function of the measuring point derives from the process task.• The CAD ‐ system can generate a measuring point list from the P & I diagrams which contains

at least device number, plain text and function.• The aspects listed above cannot be considered individually and independently from each

other. The optimum selection will only be successful with the different aspects being considered as a whole.

• Common process measuring tasks are the measurement and control of the following physical parameters:– volume flow– mass flow– density– temperature– pressure– level– pH ‐ value– conductivity

• It has to be considered that the resolution or measuring accuracydecreases with an increasing measuring range.

• The material selection of the media ‐ contacting components depends basically on the applied medium.

• Response behavior means the velocity at which a measuring point reacts on changing parameters. The required velocity of the controls to be realized with these measuring systems has to be verified.

• The planning of the device and pipe connections as well as of the assembly and electric connection of the measuring devices require so ‐ called mechanical measurement setups.

• The costs for measuring equipment are considerable and as usual, special designs cause considerable extra costs.

Control Engineering• Digital control systems may be redundantly designed and placed in an air

‐conditioned room, the control room, either centralized or decentralized designed.

• The digital control systems are connected to: local process control panels control cabinets via bus systems

• The connection of the measuring devices to the control cabinets: control cables.

• The control program : analyzes the incoming signals of the measuring points converts them and deduces the corresponding switching operations or signals (eg. Alarm)

• The two major European control program suppliers: Siemens ABB

• The control program contains all additional workflows for the operation of the plant : normal, start – up, close – down operation automatic and manual operation plant protection

• The control program is quasi hierarchically structured better handling and clarity

• The smallest unit called sub ‐ assembly controls, followed by group control, and master system control. Finally, the system controls are combined to an all ‐ including control program.

• The control schemes contain all control ‐ relevant components such as measuring points, actuating elements, feedback controls etc.

• Steps to develop control program: Set process targets Transferred targets to continuous function charts (software) to create

safety standard and safety function. Example of continuous function charts:

10

• Process and control engineers have to cooperate very closely for the development of the control program.

• However, communication problem exists between them.

• Steps to solve the communication problem: The process engineering establishes requirements specification

for the control engineers ‐verbal description of the control steps the process requires.

In the control – engineering meetings, the project manager will present the process workflow with the aid of the P & ID. Control engineers prepare continuous function charts base on the meeting.

In a second term of meetings, the control engineers will present the continuous function charts they have developed, which will then have to be released or approved by the plant manufacturer.

Thanks for Watching Please follow me / SAJJAD KHUDHUR ABBAS