Performance Analysis of Integration of IoT in Downdraft Gasifier

Performance Analysis of Integration of IoT in Downdraft Gasifier

Anirudh R (1), Anandha Sabesan G (2), Vaikunt Sudharsan R (3), Dr. P. Chandramohan (4)

(1) 2116221201008: 4 th year, Department of Mechatronics Engineering, Rajalakshmi Engineering College, Chennai, India

(2) 2116221201006: 4 th year, Department of Mechatronics Engineering, Rajalakshmi Engineering College, Chennai, India

(3) 2116221201060: 4 th year, Department of Mechatronics Engineering, Rajalakshmi Engineering College, Chennai, India

(4) Professor, Department of Mechatronics Engineering, Rajalakshmi Engineering College, Chennai, India

Abstract – The temperature of the reactor chamber is also measured with the help of temperature sensors in order to check the efficiency of the gasifier. During the experimental tests, it is found that the temperature of the reactor is approximately 550C, which represents the gasification process in the reactor chamber. The temperature of the reactor should be in the range of 700C to 800C in order to perform the gasification process. The design of the reactor should be modified in order to increase the temperature of the reactor chamber. The combustible gases produced in the downdraft gasification reactor are carbon monoxide, hydrogen, and methane, which are combustible gases and can be utilized in order to produce energy with the help of the gasification process. The efficiency of the downdraft gasification reactor depends on various parameters such as the type of fuel used and the rate of air supply.The experimental tests prove that the downdraft gasification reactor designed in this paper is utilized in order to produce combustible gases with the help of the gasification process, and this paper is useful in designing small-scale reactors in order to produce alternative energy with the help of the gasification process.

Index Terms – Lab-scale downdraft gasifier, gasification, pro- ducer gas, fixed-bed reactor, temperature analysis.

1. INTRODUCTION

   The increasing demand for energy and the need to reduce the dependence on conventional fossil fuels have created a lot of interest in using thermochemical conversion methods such as gasification. Gasification of biomass has been found to be a highly efficient method to convert solid fuels into a gaseous mixture of combustible constituents, apart from providing a partial substitute to conventional fossil fuels and the efficient utilization of locally available energy sources. Recently, the co-gasification method involving coal and biomass has been found to be of interest because of its potential to utilize the high energy density and good combustibility of coal, along with the renewable and environmentally safe nature of biomass.[1]

   The growing need for more and more energy and the need to reduce the use of conventional fossil fuels have created a very high degree of interest for using thermochemical conversion methods of gasification. Gasification of biomass is observed as a highly efficient process for the conversion of solid fuels into a gaseous fuel with combustible constituents, along with the advantage of making use of conventional fossil fuels in a partial sense and utilizing local resources more

   efficiently. In recent times, co-gasification of coal and biomass is gaining interest for making use of the high energy density and combustible characteristics of coal and the renewable and environmentally friendly characteristics of biomass.[2] Considering coal and wood chips as fuels, some different op- erational issues are raised because of different fuel properties such as moisture, volatile matter, fixed carbon, and size of the particles. Wood chips have fast devolatilization rates, and also, the temperature of gasification of coal is higher than that of wood chips, resulting in uneven reaction areas and unstable temperatures in the gasification reactor. Therefore, it is very important to perform experiments and focus on thermal characteristics, air flow management, and stability of the gasification reactor for better understanding of coal/wood chips downdraft gasification.[3]

   Although several research studies have been reported on the numerical modeling and simulation of downdraft gasifiers, very few studies have been reported on the experimental validation of downdraft gasifiers under realistic conditions. In addition, very few studies have been reported on the experimental validation of co-gasification reactors. It is very important to experimentally measure the temperature profile, pressure variations, and heat transfer characteristics of the reactor in order to assess the efficiency and performance limits of the gasifier. Experimental results are very important in validating the theory and designing the reactors for efficient production of gas.[6]

   The present work is focused on designing and developing a downdraft type of gasifier using a mixture of coal and wood chips as a fuel source and its performance evaluation. The present work focuses on analyzing the temperature distribution within the reactor, pressure characteristics during continu- ous operation of the reactor, and the supply of air and its effect on the performance of the reactor. The experimental results are obtained under specific conditions of operations and are carried out to assess the feasibility of obtaining high- temperature operations within the reactor for making it more efficient and effective. The results of the present work are found to be useful in obtaining information regarding the thermal and performance characteristics of co-gasification of coal and wood chips within a downdraft type of reactor for making it more efficient and effective.

   Fig. 1. Flow Chart Of The Project

2. METHODOLOGY

   The overall experimental methodology adopted in the present study is schematically illustrated in Fig. 1. The figure outlines the complete workflow of the project, starting from fuel preparation and reactor operation to sensor integration, data acquisition, and post-processing of experimental results. The methodology is structured to systematically investigate the thermal and pressure behavior of a downdraft gasifier op- erating with coal and wood chips under controlled conditions. Real-time monitoring of key operating parameters was carried out using an industrial data acquisition system, enabling con- tinuous observation of reactor performance and stability during operation. The acquired data were logged through a computer- based interface and subsequently analyzed to evaluate gasifier behavior, combustion stability, and operational feasibility. The detailed description of the experimental setup, instrumentation, operating procedure, and data analysis techniques is presented in the following subsections.[7]

   Experimental Setup and Gasifier Configuration

   The experimental study on the performance of the downdraft gasifier was conducted on a laboratory-scale downdraft gasi- fier, which was designed for the co-gasification of coal and wood chips. The downdraft gasifier consists of a hopper, com- bustion zone, reduction zone, and syngas outlet. The design of the downdraft gasifier ensures the co-current flow of fuel and air during the gasification process. The downdraft gasifier design is used for the cracking of fuel and the production of high-quality producer gas.The ignition of the downdraft gasifier was done by using turpentine oil before the addition of fuel into the reactor. After the ignition, the reactor was placed in a stable condition before the performance data of the downdraft gasifier were obtained. The supply of air into the downdraft gasifier reactor was externaly controlled during the experiment to maintain the required temperature inside the downdraft gasifier reactor during the gasification process.The

   experimental data on the performance of the downdraft gasifier were obtained after the stable condition was attained inside the reactor.[8]

   Combustion Zone Operation

   Combustion zone The combustion zone is the major heat generation zone. In this zone, the process of partial oxidation of coal as well as wood chips takes place. The heat generated in this zone is utilized for the production of heat for the gasification process in the reduction zone. The conditions in the combustion zone had to be monitored in order to assess the stability of the reaction process. The temperature and pressure fluctuations in this zone indicated the interaction between air and fuel as well as the performance of the reactor.[9] Instrumentation and Sensor Integration

   TTemperature and pressure sensors were placed at strategic points of the gasifier, especially around the combustion zone, to measure the real-time working parameters. These sensors were connected to a Multispan scanner, which acted as a medium of data acquisition. The scanner was connected to a laptop using an MRU 1A 00 RS-485 to USB converter, which helped facilitate communication among the devices and the monitoring system. The RS-485 protocol was employed for its reliability, long-distance communication capabilities, and resistance to electrical noise, especially for use in a high- temperature environment.[10]

   Instrumentation and Sensor Integration

   Temperature and pressure measurement instruments were used. The temperature and pressure measurement instruments used in this research are industrial-grade equipment, which can withstand high-temperature gasification processes. The temperature measurement in the gasifier reactor used K-type thermocouples. The reason behind the selection of thermocou- ples in the measurement of temperature in the gasifier reactor was based on the fact that thermocouples have a wider range of temperature measurement. Thermocouples have a quick response time in high-temperature conditions. Thermocouples used in this research are placed at critical positions in the gasi- fier reactor. Special emphasis was placed on the combustion zone.[11]

   Variations in internal pressure during the process have also been recorded with the help of PR15C-PA-020K pressure transmitters. The selection of this pressure transmitter has been made based on its appropriate pressure range and its ability to endure the process in gasification.The pressure transmitters have helped in recording variations in pressure during the conversion of fuel and the flow of gas.[13]

   All the output signals from the sensors were connected to the Multispan scanner, which was the primary equipment for acquiring data. The scanner was connected to the laptop via an MRU 1A 00 RS-485 to USB converter, which facilitated efficient digital communication between the instrumentation equipment and the monitoring system. The RS-485 protocol was chosen because of its resistance to noise and its proper application in industrial experiments.

   Data Acquisition and Real-Time Monitoring

   PSC 9084 M1 scanned the temperature values from the

   K-type thermocouples and the pressure values from the PR15C-PA-020K transmitters. The values scanned by the scanner were then transmitted and recorded by a computer- based monitoring system. The values scanned by the scanner provided a software-based dashboard of the values of the temperature and pressure in the reactor.This helped in observing and monitoring the fluctuations in the behavior of the gasifier. Such fluctuations in the behavior of the gasifier could be an indication of an unstable combustion process.The values recorded by the scanner were automatically recorded and saved in spreadsheet form by a software-based program. The recorded values can be used to analyze the variation in the temperature, the variation in the pressure, and the stability in the gasification process.[14]

   Syngas Generation and Output

   During the operation of the gasifier, the producer gas produced as a result of the co-gasification of the coal and wood chips moved downwards through the reduction zone and out of the gasifier at the syngas outlet. Although it was not within the scope of this study to assess the nature of the produced gas, the production of syngas was used as a measure of the gasifier operation. The temperature and pressure profiles were also linked with the production of syngas.[15]

   Experimental Procedure and Data Analysis

   Each experiment consisted of introducing the fuel mixture into the hopper, igniting the fuel using turpentine, and then incrementally introducing air into the reactor until steady-state conditions were reached. Once steady-state conditions had been reached, data was continually recorded using the data acquisition system. The data was then used to investigate the thermal reactor, pressure change, and stability of the downdraft gasifier during the co-gasification process of coal and wood chips.[16]

   Description of Experimental Gasifier Setup

   Fig 2 shows the fabricated laboratory-scale downdraft gasifier used in the present experimental investigation. The reactor consists of a vertically oriented cylindrical body fabricated from mild steel, designed to withstand high-temperature gasification conditions. The upper section houses the fuel feeding and ignition region, while the lower section facilitates gas flow toward the syngas outlet. The reactor is mounted on a rigid support structure to ensure mechanical stability during operation.[17]

   On the right-hand side of the reactor, four radial ports are present for temperature measurement at different heights of the reactor. The K-type thermocouple will be used and will be placed in such a way that it can be inserted for temperature measurement at different areas of the reactor, especially the combustion and reduction areas of the reactor. The temperature measurement will be helpful for analyzing the gradient behavior for the co-gasification of coal and wood chips present in the gasifier.

   On the left-hand side, there is a single connection provided to sense the pressure in the metallic tube. This connection is used to connect the PR15C-PA-020K pressure transmitter, which is used to sense the variations in the pressure inside

   Fig. 2. Setup Of The Project

   the gasifier. The tapping point is used to sense the variations in the pressure due to the resistance of the gas flow, the conversion process, etc.

   All the outputs of the thermocouple and pressure transmitter are connected to the data acquisition system for monitoring and recording purposes. The temperature and pressure measurement arrangement provides comprehensive information regarding the operational behavior of the downdraft gasifier.

3. RESULTS AND DISCUSSIONS

   Fig. 3 shows the syngas produced at the outlet of the downdraft gasifier at steady-state operation using coal and wood chips as a fuel source. The ignition of the produced syngas at the outlet of the gasifier is a clear indication of gasification and the production of a combustible producer gas composed of CO, H2, and CH4. A maximum temperature of 825 C was attained at the combustion zone using K-type thermocouples. These high temperatures were adequate to achieve the partial oxidation and cracking of the produced tars. These conditions were adequate to sustain the production of syngas, as evidenced by the steady flame at the outlet of the gasifier.

   The internal pressure of the reactor, which was measured with the help of a pressure transmitter model PR15C-PA-020K, remained constant at approximately 0.62 kPa. The low and constant pressure drop indicates the smooth flow of gases inside the reactor and the outlet system, with minimal flow instability and resistance. The stability at high temperature and pressure conditions indicates the proper working of the reactor and alsoreveals the possibility of utilizing the downdraft gasifier designed in this study for co-gasification

   operation due to the variation of gas flow rate, fuel conversion rate, and interaction of air and fuel inside the reactor. However, it was observed that there was no pressure peak and trough, indicating a smooth flow of gas inside the reactor and the outlet system, verifying that the gasifier operated under a smooth flow of gas without any blockages and backflow inside the reactor during the co-gasification of coal and wood chips.

   Fig. 3. Syngas Formation

   Fig. 4. Temperature Graph

   Fig. 5. Pressure Graph

   of coal and wood chips to produce syngas.

   The variation of temperature at different points on the height of the downdraft gasifier is shown in Figure 4. It is observed that the temperature profile is smooth and consistent throughout the entire process. There is a rise in temperature during the initial phase of heating and ignition, followed by consistent growth as the intensity of the reaction increases dur- ing the entire gasification process. It is also observed that the variation in temperature profile occurs due to different reaction zones developed in the reactor during the entire process, as higher temperatures are recorded during the combustion zone compared to the top and bottom sections of the reactor. It is also observed that the maximum temperature recorded during the entire process is 825 C, which is favorable for partial oxidation and cracking of tar and reduction reaction in the reactor.

   Figure 5 illustrates the variation of internal gasifier pressure as detected by the PR15C-PA-020K pressure transmitter dur- ing the course of operation. It was shown that the pressure increased linearly from the initial stage and stabilized at

   0.62 kPa during steady-state operation. Some observations were made regarding the variations that took place during the

4. CONCLUSION

The practicality of the coal and wood chip co-gasification process has been experimentally proved. The experiment for this study has been carried out with the help of a downdraft gasification reactor. The operation of the reactor has been made stable at a maximum temperature of 825 C in the combustion zone. The pressure at which the reactor operates stably has been measured at approximately 0.62 kPa, which are all favorable conditions for the process of partial oxidation and cracking of the produced gas. By measuring the temperature at various points, the existence of various zones in the gasi- fication reactor has been proved. Similarly, the measurement of the operation pressure has also proved the smooth flow of the produced gas in the reactor. The successful ignition and combustion of the produced syngas at the outlet have also proved the successful operation of the gasification process, which has further proved that the designed gasification reactor can produce useful syngas.

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