The effects of briquetting pressure on banana-peel briquette and the banana waste in Northern Thailand

American Journal of Applied Sciences, Jan, 2009 by Wilaipon Patomsok

INTRODUCTION

For most developing countries, it appears that biomass, particularly agricultural wastes, has become one of their most promising energy sources. The idea of utilizing the residues from agricultural sectors as primary or secondary energy sources is somewhat attractive sine they are available as free, indigenous and environmentally friendly ones. Furthermore, the decreasing availability of firewood has necessitated that efforts be made towards efficient utilization of agricultural wastes. They have acquired considerable importance as fuels for many purposes viz. domestic cooking, industrial process heating, power generation etc. Some of them, such as coconut shell, corn cob and wood waste, are ready to be directly used as fuel. The majority of them, however, are not appropriate to be used as fuel without a suitable process since they have low density, high moisture content, and low energy density. All of these issues may cause problems in transportation, handling, storage, entrained particulate emission control including direct combustion.

One of the optimistic technologies for alleviating these problems is briquetting, which has been studied by many researchers. The technology may be defined as a densification process for improving the handling characteristics of raw material and enhancing the volumetric calorific value of the biomass. Considerable amount of research on briquetting technology has been conducted. Examples of biomass studied are wheat straw, (1) (2) hazelnut shell (3), woods (4) (5), grass (6) (7), cotton (8) (9), olive refuse (10), rice straw and husk (11) as well as maize cob.(12) Generally, it is agreed that conventional process for biomass briquetting may be divided into three main categories viz. extrusion, roll briquetting, as well as piston-and-die. For the case of the latter, the pressure is developed against the end of the die to form die-shape briquettes. During the processes, as the displacement of piston becomes less and less, the pressure inside the die is continuously increased. At the end of compaction process, the pressure is the highest and the briquette is formed.

Kingdom of Thailand, covering an area of 513,115 k[m.sup.2], is located in the center of mainland South East Asia. The total land boundary of Thailand is about 4,863 km in length. This country shares the borders with Myanmar to the west and northwest (1,800 km), Laos to the east and northeast (1,754), Cambodia to the east (803 km), and Malaysia to the south (506 km). The south coast of Thailand faces the Gulf of Thailand. The Andaman Sea is on the west of the Isthmus of Kra while the Gulf of Thailand is on the east. Thailand is divided into four topographical regions viz. the mountains and forests of the north, the vast lowland of the central plains, the semi-arid farm lands of the northeast plateau, and the tropical islands and long coastline of the peninsula south. The country comprises 76 provinces that are further divided into districts, sub-districts and villages. The northern part of Thailand is a mountainous region comprising natural forests, ridges, lower foothill, and alluvial valleys. This region comprises 17 provinces namely, Chiang Mai, Chiang Rai, Tak, Kamphaeng Phet, Lampang, Mae Hong Son, Nakhon Sawan, Nan, Payao, Phetchabun, Phichit, Uthai Thani, Phitsanulok, Phare, Sukhothai and Uttaradit. With regard to the provinces, it can be divided into two distinct groups viz. the plain of the lower north from Nakhon Sawan to Sukhothai, and the mountainous upper north leading to borders of Myanmar and Laos.

One of the most important products of Northern Thailand is banana. This fruit is an important food crop cultivated for household consumption and market supply. The majority of bananas grown for commercial purposes are Pisang awak or Kluay Namwa, which is considered as an AAB (triploid) type. The production of this type of fruit does not pose any severe environmental risk. Therefore, the possibility of cultivating bananas in a sustainable way can be achieved. Generally, for banana industries in Thailand, bananas are harvested as a bunch. Then, they are delivered to a central point for inspection, cutting, curing, peeling, drying and/or other food processing prior to the packing processes at local small-factories or at village centers. After the peeling process, the banana peels are generally either uneconomically utilized or left to be disposed as they are.

The aim of the research was to investigate the properties of briquettes, produced from the blend of banana-peel and molasses. The piston-and-die technology was utilized for producing briquettes with moderate pressures ranging from 3-11 MPa. Five parameters viz. compressive strength, impact resistance, heating value, burning profile and relaxed density were studied. Besides, the amount of potential energy from banana peel in Northern Thailand was also investigated.

MATERIALS AND METHODS

An ultimate analysis of the banana peel was conducted in accordance with ASTM D5373-02 (13) and ASTM D5291-02 (14), for getting the information about banana peel composition. With regard to ASTM E1131-03 (15), thermo gravimetric test of the banana peel was also carried out using a thermal gravity analyzer, Perkin Elmer. The condition used was under nitrogen atmosphere with a heating rate of 20[degrees]C [min.sup.-1] The temperature studied was increased from room temperature to 850[degrees]C with an accuracy of [ or -]2[degrees]C. Furthermore, the heating value of the material was also examined according to ASTM E711-87 (16) method. The calorimeter used was Parr isoperibol bomb calorimeter with an accuracy of 0.0001[degrees]C.