Processing, properties and applications of HUSK ASH

稻壳灰应用研究文献

Biomass and Bioenergy23(2002)171–

179

Combustion behaviour of rice husk in a bubbling uidised bed L.Armesto a;∗,A.Bahillo a,K.Veijonen b,A.Cabanillas a,J.Otero a

a CIEMAT,Fossil Fuel Department,Avda Complutense,22,28040Madrid,Spain

b VTT Energy,P.O.Box1603,FIN-40101Jyv a skyla,Finland

Received26February2001;received in revised form19March2002;accepted29March2002

Abstract

The combustion of agro-industrial wastes in power plant seems to be an attractive possibility for the future.In Spain,the food industry generates around618,000tonnes of rice husk annually.The rice production is geographically focused in three regions:Valencia,Andalucia and Delta del Ebro.The rice husk is a suitable fuel for the uidised bed combustors.

An experimental combustion work using the rice husk as fuel was performed in a30kW th atmospheric bubbling uidised bed pilot plant of CIEMAT.The in uence of di erent variables such as temperature, uidisation velocity on the combustion e ciency and CO emissions was http://doc.xuehai.netbustion e ciency in all test runs was higher than97%.The characteristics of ash removed from the bed,cyclones and baghouse were studied.In the bed ashes,the potassium content increases along the operation hours.?2002Elsevier Science Ltd.All rights reserved.

Keywords:Rice husk;Fluidised bed;Combustion;Potassium;Combustion e ciency

1.Introduction

The declining energy supplies and severe environ-mental constraints compel us to sharply focus our at-tention on the need for additional amounts of clean energy sources.Among the energy sources that can substitute fossil fuels,biomass fuels appear as the op-tion with the highest world wide potential.

There are large quantities of residues available,as-sociated with agricultural production and processing industries and they can be used for energy produc-tion.The combustion of these residues in power plant seems to be a promising technique for the future to contribute both the reduction of greenhouse gases and the solution of the waste disposal problems.

∗Corresponding author.Tel.:+34-91-346-61-55;fax:+34-91-346-62-69.

E-mail address:lourdes.armesto@ciemat.es(L.Armesto).

Rice husk and straw are the most important agri-cultural residues in quantity(657,680million tonnes per year),amounting to43%of the total residues [1].Rice is cultivated in more than75countries in the world[2,3].Over97%of the rice husk are generated in the developing countries.The world wide annual husk output is about80million tonnes. In1997,China alone generated some54million tonnes of rice husks[4].Spain generates about 618,000tonnes of rice husk per year(1999)and this production is geographically concentrated,mainly, in three areas,Valencia,Andalucia and Delta del Ebro.

There are some problems with the rice husk treat-ment.These problems are due to a great volume of waste and its local situation(limited geographic area). On the other hand,this waste is problematic during its handling and transportation due to low density. At the moment the common fate of rice husk is the

0961-9534/02/$-see front matter?2002Elsevier Science Ltd.All rights reserved. PII:S0961-9534(02)00046-6

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