CAREER EPISODE – 1
This career episode summarizes the details of the industrial training and also the final year project conducted by me during my final semester.
Chronology : VIII semester (January 2014 to February 2014)
Name of the Organization : Madras Fertilizers Limited
Geographical Location : Chennai
Position : Student Trainee
Project Title : Sensor network based health monitoring of naphtha
During the eighth semester of my Electronics and Instrumentation course, I underwent my project training in Madras Fertilizers Limited. Mr.Sivakumar, one of the faculties in my department, who later helped us as our project guide, suggested that we visit some industry/company in order to gain some experience and get an idea on what sort of project to perform. This training period gave me a chance to see the actual implementation of all the theoretical knowledge I had gained during the four years of my professional course. This training also served as an important stepping stone in my final year project.
Aim & Objective
The aim was to learn and get a practical experience on the various processes and instruments that were in use in the company and to choose my area of interest in which I can conduct my final year project. The primary objective of my project was as follows.
Naphtha being a hazardous liquid, it is necessary to store them in isolated, well contained and monitored area.
We are focusing on monitoring of the health and the control of the naphtha storage tank.
To monitor the basic parameters of the storage tank and transmitting the values through a wireless zigbee network to the control room.
Established in 1966, Madras Fertilizers Limited is a Public Sector Undertaking under administrative Control of the Department of Fertilizers, Ministry of Chemicals and Fertilizers. They primarily focus on production and promotion of NPK fertilizers, bio fertilizers.
Plant engineer in MFL
+1 team member
Roles and Responsibilities
To understand the working of the various plants such as Ammonia plant, urea plant.
To understand how the storage tanks of naphtha are constructed and maintained.
To understand how the various health parameters of the tanks are kept under observation.
To implement a project in order to perform remote measurement of the various health parameters and control them through wireless communication.
To enable a warning through message in case of any discrepancies in the observed parameters.
To work in proper co-ordination with my team member and project guide to meet the various deadlines throughout the project period.
PERSONAL ENGINEERING ACTIVITY
In the early few weeks of our project training we were given a complete over view of how fertilizers are prepared. I learnt a lot about the actual process by visiting the various ammonia and urea plants within the industry. Ammonia serves as the major raw material in making of various fertilizers. MFL produces its own ammonia. I learnt the concepts and realities of Haber-Bosch process, the process to produce ammonia in large quantities. In this process, the plant will convert methane or petroleum naphtha into gaseous hydrogen. In MFL they use naphtha as the major raw material in the production of ammonia. The obtained gaseous hydrogen is then mixed with nitrogen in required quantities to obtain ammonia.
Naphtha storage tanks
In MFL, Naphtha was obtained from their partner company that produces petroleum. The naphtha is then stored in large tanks but those tanks were kept isolated. When asked why, I was informed that naphtha is a hazardous liquid and that is was easily flammable and highly combustible liquid and thus the tanks are isolated from the main plant. They are carcinogenic in nature,. Naphtha is also extremely volatile and can explode on exposure to high temperature surfaces. Apparently, there were a few accidents reported earlier due to the leakage of naphtha. Thus, at that time they were working on a better solution to monitor the health of the naphtha. They were manually monitoring the various observations obtained from the naphtha tanks. When my project partner and I proposed to our training guide that we would try to work on a sensor network based system for the health monitoring of naphtha tanks, he was completely supportive and also gave his inputs.
Proposed Sensor network based monitoring
My project team consisted of only two members. So my partner and I had equal share in every step of the project. Our project was to devise a Naphtha well-health guard system. I decided to divide our complete monitoring system into three as below
A set of First Level Sensors, i.e., three sensors, are commonly used which includes a
Level sensor, a temperature sensor and a pressure sensor for a single tank.
The Intelligent sensors (IS) are developed mainly for the storage tanks data processing, main fault alarm or indication, typical data storage, data/status transmission up to the third level sensors, data or status transmission between IS.
The software-defined (SD) third level sensors is designed for hundreds of storage tanks’ data storage or management, data processing, malfunction diagnosis, malfunction alarm or indication; naphtha pumping stroke adjustment command transmission down to a specific IS and the malfunction report to the maintenance staff via global system for mobile communications (GSM) SMS.
Selection of sensors
After designing the sensor network theoretically, then came the developing stage. I decided to propose an overall new system. Thus, in order to choose the first level sensors, I did extensive research on various pressure, level and temperature sensors available. I learnt that it was necessary to take the type of fluid and type of material of the container into consideration while choosing a sensor. I faced some difficulties in choosing the right temperature sensors but with the timely guidance of my project guide, I was able to pick the right sensors. We used LM35 temperature sensors. These sensors measure the temperature by giving an output voltage that is linearly proportional to the Centigrade temperature. For measuring the level of the fluid, capacitive type level sensors were chosen. Mq-5 gas sensor was used to monitor the pressure. When there is a drop in the pressure it will indicate that there’s a leakage.
Designing the system
In order to design the system, I had to do an extensive reading on embedded system to know how to link and integrate every hardware and software used. Embedded system has a specific design cycle that needs to be followed. First we need to concentrate on the transmission of data. Zigbee RF modules were used for the wireless transfer of data from the storage tanks to the control room. I chose zigbee modules because they require minimal power and provide reliable delivery of data between remote devices. In our system we have implemented serial communication system and thus have used RS232. But I had the need of MAX232 to convert the RS232 signals to TTL voltage level. I chose serial transmission as it is beneficial for long distance communications. Next step would be the selection of suitable microcontroller which would be the main controlling unit of the whole system. A wide range of microcontrollers are available. We have chosen a microcontroller over a micro processor because in a controller many features will be inbuilt. I chose PIC16F877A as the microcontroller for my project. This controller was selected as it’s a 8bit controller and follows RISC architecture. This also facilitates on chip timers and also both serial and parallel communication. Then we’ll have to program the microcontroller.
The software tools that were used are ORCAD was used to design the PCB layout. Keil IDE was used to develop the source code, compile and also simulate the code. . Embedded C language was used. PIC KIT 2 Programmer is used to dump the hex file into the PIC controller.
GSM technology was used to send alert messages to the control room in times of any leakage. We had developed pre-stored messages that will be triggered in times when any of the sensors show abnormal reading.
One of the major difficulties we had to face when designing this system was doing a real-time implementation when compared to our project situation. We could not check out system using naphtha. When we were stuck, I suggested that we test our system using oil as the element in the tank instead of naphtha, as testing with naphtha was beyond our scope. Thus we did a practical model of our system with a small tank containing oil. The other obstacle was that, our project was supposed to aim at triggering a voice call in time of need (when there’s a variation from expected values). But using voice call services in GSM technology was not clear for us and thus we settled with pre-stored text messages. When viewing the larger picture, these issues were really minor and did not remain as a setback but helped us to find an efficient solution.
Having done this training in MFL taught me a lot about the real time implementation of every theory we learned earlier.
This project also facilitated me to think efficiently of solutions at all possible situations and sometimes also to think out of the box.
Wireless transfer of data was the technology of the moment and having implemented that in a small scale of my capacity gave me great satisfaction and pride.
As it was a developing technology, it also paved way for me to be keen to any new developments happening in that field.