Project on Emergency Shutdown System

ENG 264

HD/BAS Semester 2

Spring 2012

Project on Emergency Shutdown System

Instructor's name: Hedley

Submitted by: Adel AlObaidli

 ID#: H00154942

Due date: 6^th Jun 2012

1.     Introduction to Emergency Shutdown System

Failure may result in expensive procedural and downtime consequences. Thus, the reliability of safety and availability are required to be tested frequently without interrupting the operation to guarantee the system performance.  For that reason, the ESD or SIS has been introduced. Emergency Shutdown system, or ESD, or Safety Instrumented System, or SIS, is a collection of safety instrumented functions that can be defined as a safety function associated with safety integrity level to achieve functional safety that is implemented by either a safety instrumented protection function or a safety instrumented control function, designed to process and handle a safe sequence of events under any dangerous or unsafe detected conditions. In other words, ESD or SIS is designed to respond to hazardous conditions in the plant or if no action has been taken by generating correct outputs to prevent the hazards or reduce the risky consequences. The ESD serves an additional layer of protection against equipment damage, harmful environmental impact and human injury by operating a regulatory control system. Regardless of the fact that DCS can handle emergent situations an ESD system is highly required in the field for its fast response to unsafe and hazardous situation in the plant compared to DCS. Due to the critical nature of the ESD system, the manufacturing facility of ESD system is equipped by sensors, logic solvers and control elements. The actuated shutdown valve is expected to be static under normal processing conditions for a long period of time and reliably operates only when an emergency situation arises which affects the valve on the long run. In other words the operator needs to test the ability of the valve to shutdown the plant through partial stroke test, ESD mainly scans and compares the input coming from the plant to ensure that the plant operates is a safe condition. Otherwise, it shuts  down the plant through safe sequence of actions. In detail, ESD scan can be divided into two categories which are primary and secondary scans. Primary scan includes two main tasks that are required to be completed within a specified period of time, full cycle,. The primary tasks are application and housekeeping, in which application updates the system with status of inputs coming from the field and processes the input by comparing it with a cause and effect chart to decide upon the given output. Housekeeping is related to regular checks of the healthiness of the equipment in the field, CPUs, I/O cards and network. While the secondary task is the communication in which ESD should communicate with HIS or PLCs. Under some conditions the communication will be delayed because the CPU is busy with processing other tasks, when the operator asked for updates. This problem can be overcome by leaving empty slots for each node. Communication between different ESDs and HIS (Human Interface Station) should be time synchronized in order to update the operator with recent changes in the plant. Time synchronization of different ESDs can be maintained by standard Vnet or GPS.

2.     Some terms associated with ESD system

The following paragraphs show some definitions related to ESD system:

1.     Intrinsic safe refers to protection technique for safe operation of equipment in explosive atmospheres and under irregular operating conditions or develops safe operation of process control instrumentation in hazardous areas.

2.     Hazard Operation study (HAZOP), is a structured and systematic examination of a planned process or operation to identify and evaluate problems that may cause risks to personnel or equipment.

3.     Near Miss refers to an unplanned event that did not result in injury, illness, or damage but it may result in doing so.

4.     International standard IEC 61511 was published in 2003 to provide guidance to end-users on the application of Safety Instrumented Systems in the process industries[1]. This standard is based on IEC 61508, a generic standard for design, construction, and operation of electrical/electronic/programmable electronic systems. Other industry sectors may also have standards that are based on IEC 61508, such as IEC 62061 (machinery systems), IEC 62425 (for railway signaling systems), IEC 61513 (for nuclear systems), and ISO 26262 (for road vehicles, currently a draft international standard).

3.     ESD hardware

The ESD hardware consists of cabinets that are internally connected as well as externally. as the following:

·         Power Distribution Cabinet

This cabinet is responsible for receiving the uninterrupted power supply from the unit and distributing it among all the other cabinets and equipments in accordance to their power requirement.

·         System Cabinet

This cabinet consists of I/O cards, two CPUs and ESD IO modules that connect each node to the other via ESB bus. Also, the cabinet supports the communication, data exchange, between the equipments and ESD system.

·         Marshalling Cabinet

The cabinet gathers all the wires coming from the instrument room and connects them to system cabinet by means of a Pre fabricated cable.

·         Networking Cabinet

The cabinet is responsible for the communication between the HIS and ESD system. The communication is done through Vnet IP network. The stations are connected in the network through Layer 2 switches.

4.     ESD software

Pro-safe RS is the latest Yokogawa program for representing the ESD in the plant in which the I/O cards are inserted and programmed. In addition, the program has a huge library

Conclusion

The following paragraph summarizes briefly the mechanism of the communication between HIS ,ESD and DCS systems in the plant. In the plant, HIS has to communicate with ESD, alarm server and FCS (Field Station Control). To organize the operation, token passing software is used. The software chooses one HIS as master that will control the token. The token is sent to FCS, ESD and alarm server in ordered sequence, to give permission to send or receive data for a certain station and blocks the others. The advantage of the token passing is to avoid the confusion of data. Emergency condition cannot bypass the token because the token passes rapidly in the station. For alarm server, there is alarm management system software that responds to alarms in the plant.

5.     References

http://en.wikipedia.org/wiki/Safety_instrumented_system

Portfolio task 6

There are many good things about a single global currency; also there are many bad things. Although there are positives, on the other hand I believe that it would cause problems today.

          First of all, there are some benefits of a single global currency that can be seen. Whenever you are travelling to other countries you may be using dollars; suppose that there was a single global currency, the problems of currency changing and exchange rates are history. Similarly business between countries using one currency is so much easier because you don’t worry about exchange rate risks the; same thing with the AED. Most countries do not use it, but it is accepted in many places. There are many countries that you can travel to and just take dollars with you to use. 

          However, most countries would not accept the idea. Also all countries are in different economic states. There are in astate of collapse with inflation ruining the economy. Such countries could not be brought into a world currency as it would cause massive financial instability worldwide.  

          Overall, as we can see, a global currency is a future idea but it will not happen. It would make trade and travel much easier but the problems it would cause nowadays would be impossible.

Portfolio task 5

         The line graph shows some information on the number of overseas residents traveling to Australia. And the table shows the countries whose residents went to Australia between 1975 and 2005.

          First of all, as we can see, Australia is one popular country to visit. The visitors increased year by year; in 1975 it was 10 million and 30 million in 2005. There were 20 million more visitors to Australia and it increased in 2005.

          The second table shows the countries whose residents went to Australia between 1975 and 2005. The highest number of visitors came from Japan in both years. Then came South Korea and Europe. Also USA, Britain and China had many visitors to Australia in 1975 and 2005. 

          Overall, as we can see, the total number of visitors who went to Australia increased between 1975 and 2005, and Japan had most visitors in both years.

Portfolio task 4

Most people think that a sense of competition in children should be helping them. Others believe that children who study to cooperate rather than compete become more useful in future. In this essay I will discuss both these views.

          First of all, it us useful to raise children to be competitive; it’s good for life to give maximum ability to think for something in both school and work. And this competition can make challenges with other people. If the children and other persons don’t improve themselves and achieve difficult goals, there will be no human progress. So the competition can help him in many things like in sports, medicine and many other areas, where the desire to compete with others is normal and healthy.

          On the other hand, it is also important to learn some cooperation and help the other people. It is a competitive world, so we need to stay alive and defy the odds but also we need some help from others at some point in our lives. When we help someone, it makes us better and proud of ourselves. The cooperation is an important thing in our life, so we can do better when we get some help like some ideas from others.

          Overall, if we want to be successful we must make a balance between competition and cooperation.

Portfolio task 3

Some people think a balanced diet is important and healthy; the others think that it is important for our life but not healthy all the time. A balanced diet is healthy but most people don’t know about it, so in this essay I will write some advantages and disadvantages about a healthy diet.

          First of all, let’s talk about some advantages. As we know the good health comes from a good body, if we want a good body; we must eat healthy food. But if we eat something more than we need we will be fat. There are many health clubs but not all are good; some of them only want money. Also we can do it by ourselves. If someone wants to make a diet he must make a balance between food and exercise to maintain blood pressure and save the percentage of sugar to give power for his body.

          On the other hand, most people only follow a diet without knowing what will happen in the future. If we don’t balance between diet and exercise we will not have a healthy body even if we get a nice body.

          Overall, I agree with people who know about the importance of balanced healthy food and exercise, because it will help in the future.

Protfolio Task 2

The bar chart shows the main reason for study among students of different age groups and the amount of support they received from employers in the UK. This report will analyze the important information.

First of all, the important reason for students to study is to improve their career. Now let’s talk about people younger than 26; the percentage was 80%. Then it decreased to 70% between 26 and 29 years old. It continued decreasing to 19% for those over 49. Now let’s move to the second reason which is interest. As we can see the higher percentage was 70% for those over 49 years old and the lowest was 10% for students who are under 26.

The employer support by age group dropped just over 30% for those aged 30-39. Then it increased dramatically from 33% to 44% for those over 49 years old.

Overall, the youngest age group studies over mainly for career reasons and this group also receive the most support.  

Portfolio Task 1

This table shows information regarding what sales of lunch and dinner were in a small restaurant in a downtown American business district in terms of dollars per day.

       As we can see, it can be noted each day was different to another day. At lunch the highest number was $ 2,595 on Wednesday; then decreased a little bit next day. Then it increased on Friday but it decreased again on Saturday. Then it increased on Monday and Tuesday. Let’s now talk about dinner. They took $2,900 on Saturday then it increased to $3,623 on Monday then increase a little bit on next day.

       Overall, as we can see, the sales of lunch were highest on Wednesday and lowest on Saturday. The sales of dinner were highest on Friday and lowest on Saturday. The restaurant closed on Sunday which is American weekend.