Generation of Electricity from Municipal Solid Waste

Rdf and Plasma Tourch

ABSTRACT:         

In the day to day life, the individuals and industry are generating enormous waste. Generation of waste is directly related to population growth and level of development. Waste generation is a side effect of consumption and production activities and tends to rise with the level of economic advance. Rapid growth of population mechanization and urbanization have caused generation of large quantities of waste, which finds its way mostly in to the environment due to lack of treatment and proper waste management facilities. In most of cities, waste is dumped on open ground (trenched grounds).these are potential source of many health hazards. Methane is formed by decomposition of organic matter in dump yards, which is 24 times more global warming potential than that of CO₂. Uncontrolled burning in open trench grounds leads to emission of nitrous oxides, which has 179 times more global warming potential than that of CO₂ besides creating air and water (surface and under ground)  pollution, degradation in the quality of land etc these dump yards provide a base for breeding of mosquitoes and other insects which cause health hazards to community. Hence waste management is today’s need for every cities with adoption of this new technology today’s waste would be tomorrow’s fuel. Municipalities and corporations should go for power generation.

Keywords: GHMC (greater Hyderabad Municipal Corporation), RDF (refused derived fuel), MSW (municipal solid waste)

INTRODUCTION:

Hyderabad (A.P) is generating 3500MT garbage everyday.  GHMC has adopted new technology of energy recovery from MSW management. It is already generating 6.6 MW. Electricity from 400MT garbage (MSW) daily. GHMC plans to generate 50MW power from 3500MT garbage available. Aim of this paper is to create awareness of this conversion technology from MSW to Eco-friendly RDF fuel. By using RDF in boilers SELCO (International) Ltd is generating 6.6 MW. Electricity since 8 Nov 2003. Its calorific value comes between 2500-3000Kc/kg which is comparable to TPS (Thermal Power station) coal having CV between (3000-3500) kcal/kg.

India is generating 1lakh tons MSW per day as per government of India MNES report 2001.Hence having potential of generation 1500MW from MSW. By 2012 MSW is estimated to generate 2, 00,000(2lakhs) tons/day hence it is estimated to generate 3000MW electrical power in India Vigor’s efforts have to be made. Now and ON- WARDS. From waste and follow the MSW rules 2000. By using conversion technology of waste to fuel which is called RDF .M/S SELCO (International) Ltd Hyderabad has installed MSW processing unit at Gandhamguda at

Hyderabad. Converting 400MT/day .RDF is used in boilers of power stations located at Elikatta village Shadnagar district, Mahaboobnagar (A.P) 509416. GHMC has also entered with MOU with two more firms Viz...    

Table 1:

The generated power shall be purchased by M/S Tata power trading Company at rate 3.60 Rs/UNIT, thus there would be further generation of power 23MW from 1400MT garbage per day. In third phase of HMC have invited tenders from national and international firms from balance 1700MT garbage which may generate 21MW of power. Thus 100% garbage disposal will make pollution free city from MSW-hazards point of view and garbage will become additional source of income by getting royalty 10Rs/MT garbage.  At present M/S SELCO Hyderabad. Who is pioneer in conversion technology from waste to energy are selling power to APTRANSCO W.E.F. 8 Nov 2003 and already sold 11(cores) UNITS at rate Rs 3.48/unit up to Feb 2007 and has consumed 5,30,000 MT garbage(MSW).Figures are going upwards daily on wards from Feb 2007 till date. GHMC is also getting royalty of Rs10/Ton on garbage.

WHY DO WE NEED THIS

Whenever environmental issues are being discussed today, it is increasingly ‘normal’ for discourse to turn to the issue of climate change. Whatever the issue being discussed, the potential contribution of the relevant activities to changes in climate through the emission of so-called greenhouse gases (GHGs) has become a critical determinant of how the environmental performance of those activities is perceived.

A Consultation Document makes this a central platform for the argument in favor of changing course for the management of waste.1 The Consultation Document was accompanied by the release of a document prepared by ERM which sought to understand the implications of different policy changes for the impact of waste management upon climate change.2 The debate around climate change has also become intertwined with the discussion concerning the generation of energy. The majority of energy generation in the UK generates greenhouse gases (GHGs), and the quantity of GHGs generated per unit of energy depends both on the fuel used and the efficiency of the generation by the power stations used.

WAYS OF PRODUCING ELECTRICITY FORM WATSE (Material and Methods):

Generally there are two ways to produce electricity form the waste.

A) DIRECT COMBUSTION

B) INDIRECT COMBUSTION

A) DIRECT COMBUSTION:

In the Direct combustion method the whole process of generating takes place in the same plant. The following diagram shows how the electricity is generated by the first method.

In this method firstly the MSW is brought to the power plant with the help of huge trucks which can carry the waste up till 10-20 tones. Then it is being dumped into the waste storage bunker. Then with the help of hoist crane the waste is picked and given to the feeder, feeder feeds the waste to the Melter, where all the waste is burned with the help of a plasma torch.                                                                                            

Fig1 (Block diagram of direct combustion)

The heat generated by burning process is used to boil the water and get steam. The steam generated is then sent to the steam turbines which are connected to the generators, turbines due to high pressure of steam rotate and there by producing electricity. The major advantage of this plant is that it uses two boilers, which thereby generates double amount of steam and more electricity. Another advantage of this plant is that instead of using fresh water from rivers, we use the waste or contaminated water. The water is first pumped to a purification plant where all the harmful contents are segregated. The gases evolved from the boiler are sent to a post combustion chamber, where which is heated and further sent to a gas turbine, which again gives us electricity.

B) INDIRECT COMBUSTION METHOD:

In the indirect combustion method, the electricity generation from the MSW is done in two parts. Firstly the MSW with the help of huge trucks is brought to the MSW processing plant. At this plant the MSW is segregated into diff parts, like metals aside, the organic waste aside and the others like plastic, glass are brought aside.

The waste is first passed through magnetic field, where the metals get aside, and then with the help of many other modern machines the other materials are segregated. The metal is sent for recycling. The burnable waste is then dried and made in forms of small pallets called the Reduced Derived Fuel (RDF) as shown below.

      Fig 2 (input to the indirect combustion process)

         Fig 3 (Block diagram of indirect combustion)

         Fig 4 (output of the indirect combustion)

TESTING RESULTS OF RDF [REFUSE DERIVED FUEL]:

The RDF has been tested in various reputed National Laboratories. Broadly Refuse Derived Fuel (RDF) composition will be as follows

Calorific Value: 2000 - 2500Kcal/Kg

Proximate Analysis in%

Table 2

Ultimate Analysis in%

Table 3

Emission Characteristics:

The Emission characteristics of RDF are superior compared to coal with less NOX, SOX, CO & CO2. In our RDF Burning emissions no Traces of Dioxins or Furons were found at parts per billion levels (ppb) as per the test reports of reputed labs. The burning of RDF in place of coal reduces the Green House Gases. Thus it is an eco friendly fuel. The dual advantage of MSW processing is that is not only solves the garbage disposal problems but also produces the much needed electricity. Soil enricher and fly ash are the useful byproducts. Through our innovative efforts we have proved that waste generated from Municipal Solid Waste is also useful.

CASE STUDY

SELCO (International) Ltd,

Survey No 43

Gandhamguda Village, Rajendra Nagar Mandal

R.R District 500008

AP, INDIA

At present this is the company which is helping Hyderabad become better by consuming the MSW and giving electricity in return. Following are the detail of the company, its production, consumption, earnings etc. Projects are partially funded by technology development Board and Indian renewable energy development agency (IREDA) and promoter equity. Applications of RDF is done in cement plants, paper industries, and small power plants (stroke fired Boilers) in India and abroad.

Segregated High C.V Fraction of MSW

SALIENT FEATURES OF MSW PROCESSING PLANT-

1.   There is one MSW processing UNIT of M/S SELCO (International) Ltd at Gandhamguda, HYD and power plant using RDF fuel is at  Mahaboobnagar District of AP.

2.   Land is given by GHMC on nominal lease for  30 Years and garbage shall be getting from  GHMC

3.   Garbage to RDF fuel conversion plant is Operative Since year 1999 running Successfully till date.

4.   Totally indigenous technology

5.   Drying of garbage with solar thermal panels.

6.   Online drying of garbage with rotary kilns.

7.   Automatic segregation of garbage.

8.  Similar plant is operating at Jaipur also for Cement Industry.

RDF FROM PROCESSED MSW                                                                                                                                                     

1. Separation at source

2. Sorting or Mechanical Separator                       

3. Size Reduction                                                    

4. Separation &Screening                                   

5. Blending                                                                 

6. Drying & palletizing

7. Packaging

8.  Storage

CV of components of MSW/Heat value           

 1. Plastic------40MJ/kg

 2. Wood-------15-17MJ/kg

 3. Tire ---------30 MJ/kg   

 4. Sewage Sludge—16—17MJ/kg

 5. Animal waste –16—17 MJ/kg 

ADVANTAGES:

1. Methane evolution caused due to the dumping of waste is eliminated.
2. Electricity is produced.
3. On segregation of waste we get metal and many other renewable materials.
4. GHMC is paid for the waste.
5. Land used for dumping will reduce.
6. Elimination of mosquito breeding.

DISADVANTEGES:

1. Initial investment is high.
2. Waste from the power plant it to be managed again.
3. Maintenance cost is high.
4. Health hazards for people working. (If safety precautions are ignored)  

CONCLUSION:

The continuing growth in demand for fossil fuel has necessitated the search for alternative sources of renewable energy. One source of renewable energy, which has not been given adequate attention, is waste, particularly solid waste.

This gives various aspects involved in recovering energy from waste. It presents a mosaic of technologies, country experiences, and socio-economic and health issues. Instead of giving an exhaustive coverage of all the technologies, it focuses on some success and failure stories from developed as well as developing nations.  The municipal solid waste should be considered as alternate source of energy. New technology of conversion of MSW (garbage) to useful RDF (fuel) is today’s requirement. Low grade coal used in power stations are having high ash content from 40-45 %     while  RDF fuel is having 20-25 % ash content is considered  better quality due to less ash contents and less pollutant.

Every municipal corporation should use this technology to reduced pollution, preserve coal, and reduce production of green house gases protection the ozone layer. Co₂ reduction can earn CDM funds carbon credits through clean development mechanism. Further to above ministry of non conventional energy sources has estimated 2 lack tons garbage by 2012 which can generate 3000 MW electricity. Further it is estimated that by year 2017 the MSW will go up to 3, 00,000 tones per day which may generate 5000 mw electricity. .This dream has to be full- field by hard work and dedication.

REFERENCES:

1. Recovering Energy from Waste by

Velma I. Grover and Vaneeta Grover:

1. Waste To Energy by

 M.P Poonai Upender Pandel

1. Solid waste to energy conversion by

Harvey Alter

1. www.ghmc.gov.in

1. www.adplatech.com

1. www.waste-management-world.com

1. www.selco.com

1. European commission – directorate general environment study on hazardous household waste (HHW) with a main emphasis on hazardous household chemical (HHC) final report, July 2002.

1. Gendebien, A.; Leavens, A.; Blackmore, K.; Godley, A.; Levin, k.; and Franke, B. “Study on hazardous household waste with a main emphasis on hazardous household chemicals. July European commission – directorate 2002.

1. Jain Bharat, 2004. Cleaner production – Gujarat scenario, In: industrial waste treatment and environmental management, Nov- Dec,2004

Contacts

pawananilpawar@gmail.com