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SEMINAR ON

 

BIOMASS GASIFICATION

 

A Boon For Island Electrification

- Susobhon Kundu

Introduction

 

The new-found technology of putting waste materials to use is now known as biomass technology. The commonly used biomass materials for energy production include wood and wood wastes, agricultural and agro-industrial wastes, sewage sludge and municipal solid wastes. Today, it is estimated that nearly 45% of the total energy consumption in the country is fulfilled from all these resources. Anaerobic digestion, pyrolysis, combustion and gasification constitute the four major categories of biomass conversion technologies.

What is Biomass Gasification!

Of these, the biomass gasification route is essentially the conversion of solid biomass into a combustible gas mixture, normally known as the producer gas. This process is used typically for the woody biomass and it involves the partial combustion of such biomass. Due to this partial combustion, carbon monoxide and hydrogen gases are produced, both of which are combustible. The producer gas could be either burnt for thermal applications or used for replacing diesel oil in a dual-fuel engine, for mechanical applications and generation of electricity. The Baroda-based Ankur Scientific Energy Technologies (ASCENT) is a front-runner in developping the wood-based biomass gasifier systems. It has now successfully transformed the Gosawba island of Sunderbans delta in West Bengal into an energy island. Here, about five biomass gasifier units of 100 kW capacity each have been installed by the company, with active support of West Bengal Renewable Energy Development Agency (WBREDA) and the Ministry of Non-conventional Energy Sources (MNES).

Use of Biomass Gasification

Gosaba is one of the several important islands of Sundarbans, some 115 km from Kolkata. It had no grid power connection till 1997,until a WBREDA survey favoured the use of biomass gasifier technology here. Accordingly a 500 kW (5*100kW) gasifier based power plant was set up for the electrification of five villages, with a population of about 10,000 people. To meet the raw feedstock requirements, nearly 100 ha of waste land on the island was

converted into an energy plantation area.

The gasifiers installed are basically downdrafted types designed to handle the woody biomass.These are collectively capable of supplying nearly 250 cubic meter of gas with a calorific value of 1000 kcal/cu m. there has been no major shortage of raw feedstock for operating these units, though the high-moisture content at times needs attention.

The plant was initially tested in June 1997 with a bare minimum load of just 16 kW from about 19 consumers. However, consumers opting for the biomass power. Presently, total number as the confidence level increased gradually, so did the number of of consumers is nearly 511, with 68.3% of them being from the domestic category alone, followed by the commertial (30.7%) and industrial (1%) categories. The cost per unit of electricity to the consumers ranges between Rs.3.50 Rs.4.0.

SUSOBHON

However, Dr. B. C. Jain, the managing director of ASCENT is quite hopeful of electricity being supplied @ Rs. 2 per unit for a consumer size of 800 users. According to him, the total cost of building this 500 kW facility was about Rs.95 lakhs. If the same capacity is installed today, it may cost about Rs.125 lakh.

Currently, the consumers in Gosaba get power for about 6 hours daily and the consumption of diesel is 0.13 litre per unit at 80% load. Dr. Jain says that the biomass gasifier plant of this capacity can generate in excess of 3 million units of electricity, if optimally used. The consumption of biomass in a dried form is

about 900 gram per unit of power produced at the site. Also the expected yield of biomass in a plantation area of about 100 ha is about 10 MT/ha/yr.

This experimental project is now being seen as a successful replication model. It is mainly due to the low cost of the power generation achived via the biomass route under these remote site conditions. However, For relatively small loads, solar photovoltaic (PV) technology, which converts the incident solar radiation into useful electricity for meeting lighting application etc., is the right choice. In fact, WBREDA and MNES have already prepared the blueprint to electrify all the 16 villages of sagar islands by PV. Till date about 9 such villages have been covered, Where about 5 PV power plants of 25 kW capacity each are operating successfully. Each of these plants uses two battery banks (low maintenance lead acid batteries) of 800 ampere-hours capacity each, at a nominal Voltage of 120V. The consumers can operate a load comprising

three lighting points and two plug points, for five hours a day, at a monthly payment of Rs.120 per month. These PV projects have been funded to tune of about 60% by the MNES and state government, with the balance funding of 40%,provided as a soft loan, by the Indian Renewable Energy Development agency (IREDA), under the World Bank line of credit.

Conclusion:

The die is now strongly cast in favour of renewable energy (RE) technologies, if the union cabinet finally clears a capacity addition of 12,000 MW through renewable, under the framework of a modified national renewable energy policy. Out of this, nearly 3500 MW of this capacity is to be produced via the biomass gasification route alone. However, the Sun may shine bright on all the RE technologies only if the renewable energy community as a whole gears itself fully for all this.

 

GIVE UR RESPONSES AT:

susobhon2002@yahoo.com

 

PRESENTED BY:

SUSOBHON KUNDU

Mechanical engineering

 

Bibliography:

Magazine: Science reporter

 

Note: The above seminar was presented by me and hence I am letting others to get some help from it. This matter has been taken from some good magazines,books and sites and has been checked thoroughly by me and my friends, even if there are any mistakes kindly forgive me plz. This matter doesnot contain any copyright of ours. Its a property of respective books and magazines from which we have taken this matter.