Somrat Kerdsuwan

A Novel Hybrid Design of Incineration-Gasification for Energy Saving

Nowadays, Municipal Solid Waste (MSW) becomes a crucial problem worldwide where it is created the impact to environment, social as well as health. The non-sanitary landfill is widespread used for waste disposal in the rural area because of its low investment and operation cost. However, it has negative effect on human health and environment. Thermal treatment of MSW by incineration is considered as an option for effective treatment technique due to the fast reduction in mass and volume of MSW. However, with high moisture content in MSW, it is necessary to use auxiliary fuel in order to maintain the high temperature of combustion process and led to the high operating cost, especially for the small scale incinerator without energy recovery. A novel hybrid incineration-gasification can be used in order to overcome this drawback by using a downdraft gasifier with Refuse Derived Fuel (RDF) as feedstock to generate the syngas which can be substituted the auxiliary fuel. Hence, this study emphasizes on the development of a novel hybrid incineration-gasification as a cleaner technology to get rid of MSW generated with a destruction capacity of 30 ton per day (TPD). The novel system comprises of a controlled-air incinerator with two combustion chambers, automatic feeding machine and wet scrubber. A 100 kg/hr downdraft gasifier has aim to use RDF from dry fraction of MSW as feedstock to produce syngas to substitute the auxiliary fuel used in the secondary burner of the incinerator in order to maintain the desire its temperature. This cleaner and novel hybrid technology can implement to get rid of MSW properly for energy saving and sustainable development.

Innovative Design and Manufacturing Technology of High Temperature Air Combustion (HTAC) Municipal Solid Waste Incinerator

Incineration is a Thermal Treatment Technology (3Ts) that could be expressed as the way to get rid of waste effectively with the reduction of its mass and volume. However, to control the combustion process efficiently, especially combustion temperature, with low energy content in Municipal Solid Waste (MSW), an additional fuel is needed and leads to increase of operating cost compared with other disposal option. High Temperature Air Combustion (HTAC) has been successfully demonstrated in a lab-scale incinerator for energy saving and pollutant reduction, especially NOx. This article has the objective to design and manufacture the prototype scale High Temperature Air Incinerator with a capacity to treat MSW of 12 Ton per day. The system consists of an automatic feeding machine to feed the waste into the primary combustion chamber (PCC) where the combustion takes place. The push ram is used to push the burning waste and fall down to the lower hearth. Primary combustion air is supplied into PCC at the amount lower than the stoichiometric requirement to produce the combustible gas which is flown into the Secondary Combustion Chamber (SCC) located above PCC. Secondary combustion air is injected to react with combustible gas to convert to the product of complete combustion. A part of hot flue gas which is flew out from SCC is reverted and mixed with fresh air, in order to reduce oxygen concentration, before passing through the heat exchanger tube bundle which is placed inside SCC in order to exchange heat with hot flue gas. To manufacture the designed incinerator, the detail of materials used as well as the frabication method is explained. It has been shown that HTAC can be applied for thermal destruction of waste successfully, in term of energy saving and pollutant free. Benefits of this research work will promote the using of thermal treatment technology of dispose of MSW with lower operating cost and lower pollutants.

Innovative Bio-char Briquetting from Corn Residue Using Torrefaction Process

Each year, millions of tons of corn are harvested from the farm fields. Their residues, e.g. stems/leaves and husks, are left in the field, while the empty cobs are processed at the mills and the byproduct is inefficiently used as low-grade fuel. The stems/leaves and husks are not used as fuel because of their poor fuel quality and because they are difficult to handle. Innovative bio-char briquetting from corn residues to improve their fuel properties has been proposed using the torrefaction process. The temperature and retention time for this process affects properties of the empty cobs, stems/leaves, and husks from the residual corn, which helps to improve their heating value and changes the volatile matter and fixed carbon proportion in the fuel. All of the torrefied corn residues is hydrophobic, which has less ability to absorb water due to the change in pore structure. The biochar from the corn residual can be used as premium feedstock for heating purposes with high heating value and low smoke.

Simulation of Green and Clean Electrical Power Generation of a 500 Ton per Day Waste Incineration Plant with High Moisture Content and Low Heating Value

With the increasing amount of waste together with the high development of the country, the high amount of waste needed to be treated properly in order to lower the impact to the environment. Waste to Energy through incineration is considered as the appropriated technology to convert green and clean energy from discard matters, especially for the waste that has the mixing composition and has not segregate its composition in the developing country. Therefore, it is essential to simulate its combustion process to see how much of electrical power that can be generated and purpose the appropriated technic in order to improve its efficiency. This research deals with the process simulation of using incineration technology with high moisture content and low heating value in developing country. The simulation of 500 ton per day incineration technology was conducted by the unit operation in Aspen Plus® program in order to forecast the capacity of electricity production and the contaminants in flue gas emission. It was found that, even high moisture content and low heating value of waste, incineration can be one of the solutions to dispose waste properly and can recover green and clean energy in the form of electricity ranging from 3.78-6.29 MWe depending on waste’s quality. This green and clean energy recovery from waste could be used to reduce the using of fossil fuel in order to mitigate the emission of the greenhouse gas to atmosphere.

In-Depth Performance Evaluation of RDF from Landfill Reclamation for Green Electricity Generation in a Downdraft Gasifier

Landfill reclamation is one of the possibilities to reclaim land resources and recover energy hidden in garbage into green and renewable energy. This study aims to conduct a feasibility study of using waste reclaimed from old landfill, called mined Municipal Solid Waste (mined MSW), for power generation in a 50 kW downdraft gasification system and to optimize its operating conditions. Waste reclaimed from dumpsite in Phuket municipality, southern part of Thailand, consists of mostly plastic fraction and has a higher heating value of 28.68 MJ/kg. In this study, waste reclaimed is first solar dried and cut into small size before using as loose-RDF in 10 kg/h downdraft gasification process to study the gasification process. Three experiments with different air flow rates of 12, 18, and 21 Nm3/h were carried out, and it was found that the heating value of producer gas from loose-RDF ranged from 0.89 to 2.71 MJ/Nm3 which was considered to be very low for further use in diesel engine for power generation. Hence, the densification of RDF was performed in order to improve the RDF properties. After densification process, three experiments of dense-RDF gasification with different air flow rates of 18, 21, and 24 Nm3/h were repeated again. The results indicated that by using dense-RDF, the heating value of producer gas increased to 2.46–2.99 MJ/Nm3 and the cold gas efficiency reached 43.26–56.22 %. At the air flow rate of 21 Nm3/h, the producer gas has the maximum heating value and maximum cold gas efficiency. Although dense-RDF can produce the higher heating value of producer gas and can achieve the higher cold gas efficiency, it consumed more energy in preparation process which was accounted for 0.12 kWh per dense-RDF 1 kg. For the experiments in a 50 kg/h prototype scale downdraft gasifier, dense-RDF was gasified with three different air flow rates of 73, 85, and 101 Nm3/h. It was found that the maximum heating value of producer gas of 3.12 MJ/Nm3 was achieved at the air flow rate of 101 Nm3/h. After passing through gas-cleaning process, the producer gas can be used to fuel a diesel engine in continuous mode for power production. The electrical energy and overall efficiency as well as the quality of lube oil and wear of engine part have been reported.