KATHMANDU UNIVERSITY

SCHOOL OF ENGINEERING

DEPARTMENT OF MECHANICAL ENGINEERING

PROJECT REPORT

Design and fabrication of "Unmanned Glider”

A final year mid term project report submitted in partial fulfillment

Of requirements for the degree of

Bachelor of Engineering

By:

Bipul Acharya (31051)

Bhaskar Dahal(31057)

Samridha Neupane(31067)

Sumit Piya (31069)

November 2010

CERTIFICATION

THIRD YEAR MID TERM PROJECT REPORT

on

"Design and Fabrication of Unmanned Glider"

by:

Bipul Acharya (31051)

Bhaskar Dahal(31057)

Samridha Neupane(31067)

Sumit Piya (31069)

Approved by:

1. Project Supervisor

(Signature) (Name) (Date)

2. Head/Incharge of Department

(Signature) (Name) (Date)

ABSTRACT

In the developing countries energy requirements for cooking often has biggest share in the total

national energy demand and is normally met mostly by biogas. The fabrication of our “Gasifier”

regarding the detail will be done locally. The performance tests will be done by altering the fuels.

We also have plans to fabricate a new model with more efficiency in upcoming semester.

The design of the Gasifier is adopted from a Gasifier model in CRTN which was reported to be

brought from Philippines. We had few modifications for ease and for greater efficiency.

Chapter one is the background and objectives. Chapter two discusses about technology and

literature survey. Chapter three discusses about product description and performance. Chapter

four is about progress summary and chapter five is discussion and conclusion.

ACKNOWLEDGEMENT

Collection of various efforts and imposing upon the single target is itself a comprehensive job.

Persons involving in those activities are recognized as seen or unseen actors. We sincerely

acknowledge the guidance provided by Asso. Prof Soma Sekhar Adiga and Mr. Pratisthit Lal

Shrestha, Department of Mechanical Engineering, Kathmandu University.

We cannot forget the precious help provided by CRTN (center for rural technology Nepal) and

its members for designs.

At last but not the least we would like to thank our seniors Mr. Hemanta Raj Mainali and Mr.

Kisor Duwadi and Mr. Rupak Timilsina for their precious suggestions.

Symbols and Abbreviation:

CRTN: Center for Rural Technology Nepal

WBT: Water boiling Test

KPT: Kitchen performance Test.

LIST OF FIGURES

Fig No. Title Page No.

1. Complete gasification process

2. Updraft Gasifier

3. Down draft Gasifier

4. Twin fire Gasifier

5. Cross fire Gasifier

6. 3D diagram of Portable Gasifier

7. 2D diagram of Portable Gasifier

TABLE OF CONTENTS

Abstract I

Acknowledgement II

List of figures III

Chapter 1: Introduction 1

Chapter 2: Technology and literature survey 2-4

Chapter 3: Product description and performance 5-6

Chapter 4: Progress Summary 7-8

Chapter 5: Discussion and conclusion 9

CHAPTER 1

INTRODUCTION

1.1 Background and objectives

1.1.1 Background

It is known to everyone that we are about to face a major energy crisis in the upcoming decade. It

is due to overuse of the non renewable resource and boycotting the use of renewable resource.

The petroleum products cannot be used by the major population of the world in their day to day

activities as they are costly, thus major world population depends on the organic fuel (except

petroleum) i.e. Wood and wood products and organic matters.

In our country, about 80 percent of the population lives in the rural area. If we see the energy

consumption scenario of Nepal, about 84 percent of energy is gained from woods and wood

products (ADB, 2006). Among this energy about 64 percent is consumed to cook food and

almost 16 percent is used to prepare food for cattle. This scenario shows that the forest is being

exploited at a speeding rate; also incomplete combustion of firewood produces carbon monoxide

and carbon dioxide, thus polluting the domestic environment.

The main objectives of this project were as follows:

- To fabricate a gasifier model.

- To test the gasifier's efficiency with different types of fuel.

- To modify the gasifier and obtain higher efficiency.

CHAPTER 2

TECHNOLOGY AND LITERATURE SURVEY

2.1 Gasifier

Gasification is the conversion of solid carbon fuels into carbon monoxide by thermo chemical

process. The gasification of solid fuel is accomplished in air sealed closed chamber under slight

suction or pressure relative to ambient pressure. Gasification is complex thermo chemical

process. Splitting the gas into strictly separate zones is not realistic but nevertheless conceptually

essential. A gasification process occurs at the same time at the different parts of Gasifier.

2.2 Pyrolysis:

It is the thermal decomposition of the biomass fuels in absence of oxygen. Pyrolysis involves

release of three kinds of products: solid, liquid and gases. The ratio of products is influenced by

the type of biomass fuels and the operating conditions. The heating value of the gas produced

during the Pyrolysis is low (3.5-8.9 MJ/m3). It is noted that now matter how a Gasifier is built

there will always be low temperature zone where Pyrolysis takes place generating decomposed

hydrocarbon.

2.3 Pyrolytic gasification:

Pyrolytic gasification operates at 450-600ºC with an external heat source to produce a rich

flammable gas plus free carbon (~20-30% and mineral ash). The flammable gas can then be

burned or converted to synthesis gas in a second process by steam or oxygen reforming.

2.3 Types of Gasifier:

According to the design and process of work Gasifier is mainly classified into 4 types, other than

these there exists other type of Gasifier which is output of the modification in the above ones.

Thus there are following types of Gasifier:

1. Updraft Gasifier

2. Downdraft Gasifier

3. Twin-fire Gasifier

4. Cross draft Gasifier

1. Updraft Gasifier:

An updraft Gasifier has clearly defined zones for partial combustion, reduction, and Pyrolysis.

Air is introduced at the bottom and act as countercurrent to fuel flow. The gas is drawn at higher

location. The updraft Gasifier achieves the highest efficiency as the hot gas passes through fuel

bed and leaves the Gasifier at low temperature. The sensible heat given by gas is used to preheat

and dry fuel. Disadvantages of updraft gas producer are excessive amount of tar in raw gas and

poor loading capability. Hence it is not suitable for running vehicle. 

2. Down draft Gasifier:

In the updraft Gasifier, gas leaves the Gasifier with high tar vapor which may seriously interfere

the operation of internal combustion engine. This problem is minimized in downdraft Gasifier. In

this type, air is introduced into downward flowing packed bed or solid fuels and gas is drawn off

at the bottom. A lower overall efficiency and difficulties in handling higher moisture and ash

content are common problems in small downdraft gas producers. The time (20-30 minutes)

needed to ignite and bring plant to working temperature with good gas quality is shorter than

updraft gas producer. This Gasifier is preferred to updraft Gasifier for internal combustion

engines.

3. Twin fire Gasifier:

The advantage of co-current and counter-current Gasifiers are combined in a so a called twin-fire

Gasifier. It consists of two defined reaction zones. Drying, low-temperature carbonization, and

cracking of gases occur in the upper zone, while permanent gasification of charcoal takes in

lower zone. The gas temperature lies between 460 to 520 o C. Total process takes place with

under pressure of -30 mbar. Twin-fire Gasifier produces fairly clean gas.

4. Cross draft Gasifier:

Cross draft gas producers, although they have certain advantages over updraft and downdraft

Gasifiers, they are not of ideal type. The disadvantages such as high exit gas temperature, poor

CO 2 reduction and high gas velocity are the consequence of the design. Unlike downdraft and

updraft Gasifiers, the ash bin, fire and reduction zone in cross draft Gasifiers are separated.

These design characteristics limit the type of fuel for operation to low ash fuels such as wood,

charcoal and coke. The load following ability of cross draft Gasifier is quite good due to

concentrated partial zones which operates at temperatures up to 2000 o c. Start up time (5-10

minutes) is much faster than that of downdraft and updraft units. The relatively higher

temperature in cross draft gas producer has an obvious effect on gas composition such as high

carbon monoxide, and low hydrogen and methane content when dry fuel such as charcoal is

used. Cross draft Gasifier operates well on dry air blast and dry fuel.

CHAPTER 3

PRODUCT DESCRIPTION AND PERFORMANCE

We fabricated the portable gasifier. We chose to fabricate this Gasifier rather than other types of

Gasifier; it is because of the following causes:

1. It is a simple model and can be fabricated at comparatively low cost.

2. It is an updraft model, thus gas can be collected easily.

Physically the Gasifier can be divided into three different parts.

a. The combustion chamber (from where heat is supplied).

b. The Pyrolysis chamber where chemical action takes place.

c. The hood from which is the outlet for gas.

Here is the physical description for the “Portable Gasifier”:

Physical specifications of portable gasifier after modification:

Height of combustion + Pyrolysis chamber: 35 cm

Height of combustion chamber: 6 cm

Height of Pyrolysis chamber: 29 cm

Circumference of Pyrolysis chamber: 65 cm

Insulation layer: 3 cm thickness, covered externally by steel plate.

HOOD:

Height of hood: 19 cm

Circumference of hood: 25 cm

Slanted height: 11 cm

Base:

Lower portion closed

2 sides opening

Opening:

5*8 cm

No of air inlet pores in hood: 43 (random spacing)

Height of stand to place pot: 68 cm

CHAPTER 4

PROGRESS SUMMARY

4.1 Task accomplished:

We successfully met the aim that we took before starting the project. We designed,

fabricated, modified and tested the gasifier. We did several tests using wood and

lapsi seeds as fuel. We carried gas analysis too.

4.4 Problem Encountered:

The only problem we faced was in making the circular cylinders.This problem was resolved after

a hard work.

4.5 Cost Estimation:

Before modification and testing:

Iron plates (4 ft): Rs.900

Rods(4 m): Rs.300

Screws and extra: Rs.550

for modification and testing:

fuel(lapsi seeds, wood, briquetts): Rs 1500

Modification costs(upper stand, movable grid): Rs 1000

Total cost Estimated: Rs 4450

CHAPTER 5

DISCUSSION AND CONCLUSION

We have headed to fabricate a technology that can be useful for the major population of Nepal

under the economic demarcation. We did not choose any projects that are highly technical

because we believe that the engineering ethics does not teach us only to research on the projects

that are advanced but are of little importance to the society we stand. Our project when

completed successfully will help more than 70 percent of the total population of the country

which we believe are middle class and lower class. This will help them to maintain a healthy

household environment and also to save the forest.

Thus we can conclude that the project of devising a Gasifier will be fruitful. In coming days to

we shall be working on such projects will have a high importance in uplifting the condition of

the Nepalese society.

FIGURES

Stage 1 Stage 2 Stage 3 Stage 4 Stage 5

Harvesting Processing

Source: Taure 2004

Figure 1: complete gasification process

Fig 2: Updraft Gasifier

Chopping

Briquetting

Biomass

Dehydration

Drying

Gasification Gas cleaning

Motor

Turbine

Boiler

Figure 6: 3D diagram of KUMET Gasifier

Figure 7: 2d view of purposed gasifier

Hood

Pyrolysis chamber

Combustion chamber

Figure 8: 2d view of modified gasifier

Figure 9: To be modified in next semester

SOURCE CITATION:

1. CRTN

2. http:// www.tpub.com/alternativefuel/biofuel/tech/gasifier.html

3. http://improvedstoves.blogspot.com/

4. http://www.gekgasifier.com/tag/gasifier/