Chapter 14.Briquetting in Brazil

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Background

Brazil, like India, has a very large and diverse energy economy with substantial regional differences as well as rural/urban splits. Since the mid-'70s, Brazil has adopted a broadly consistent set of energy policies which have the objective of increasing the use of indigenous fuels. This objective, common to many countries, has been given a specifically Brazilian bias by a very strong commitment to the development of biofuels as we'd as to hydroelectric power. Although the heavy capital investment of some of these programmes is now prompting a change of emphasis, the underlying policy has been firmly put in place.

This policy has resulted in changes in the energy economy which are probably more far-reaching than in any other country. The only comparable experience has been the determination of France to transform its power sector by the use of nuclear power. The changes made have been all the more remarkable by being undertaken at a period of rapid economic growth in which the demand for energy was increasing rapidly.

In the period 1976-86, total primary energy consumption grew from 109 mtoe to 177 mtoe and, in the same period, imported fuel - mainly crude oil - dropped from 43 mtoe to 36 mtoe. This drop in oil imports was partly brought about by increasing Brazilian oil production but there were also huge increases in indigenous hydropower (24 mtoe in 1976 to 53 mtoe in 1986) and in the use of alcohol car-fuel based on sugar-cane (7.2 mtoe in 1976 to 20.4 mtoe in 1986).

Another, and less well-known shift, was a big increase in the use of wood as a fuel even in large industrial units. Recorded firewood use increased, from 27 mtoe to 31 mtoe, and unrecorded firewood may have increased still further. Much of the increase in firewood was due to a growth in bulk charcoal production to provide the growing steel industry with a substitute for imported metallurgical coke. Charcoal production increased from 2.9 mtoe in 1976 to 6.6 mtoe in 1986. The massive increase in alcohol production also produced a flourishing growth in the use of sugar-cane residue (bagasse) as a fuel; from 5.3 mtoe in 1976 to 11.7 mtoe in 1986.

Much of the dynamic for this change has come from the public sector but most of the new production facilities for biofuels are in the private sector as is the supply of fuelwood. There has been a parallel strand of policy to reducing oil imports, that is a reliance upon Brazilian technology so that most of the new energy facilities are built and operated by Brazilian-based companies.

Agriculture residues

Brazil grows nearly all crops in significant quantities; the main ones with significant residues and their production in 1986 were as follows:

There is clearly a large potential residue base dominated by the huge production of bagasse whose disposal is a significant secondary industry by itself.

The form of agriculture is varied with small and medium-sized farms in the southern states and much larger estates in the north together with small-scale peasant agriculture.

There has not been any central policy towards the use of agro-residues as fuel except in the case of bagasse where the producers' cooperative, COPERSUGAR, has looked at ways to dispose of surplus bagasse. Most (up to 90%) appears to be used, probably rather inefficiently, in the sugar-mills and alcohol plants but this still leaves some 4.5 million tonnes to be disposed of.

Development of briquetting

The first briquetting machines in Brazil seem to have been installed by a company called HANSA, a Brazilian company set up to manufacture the Hausmann type machines in a joint venture with European manufacturers. The first machines sold were to rice-mills; overall, the company sold about 100 machines before going bankrupt in 1985. The reasons for the bankruptcy are said to have been under-capitalisation in the difficult business conditions of that year when there was a financial squeeze to reduce inflation and cope with the external debt problem.

Two other Brazilian companies have sold machines; there do not seem to have been any non-Brazilian entries, possibly because of the strong bias in favour of Brazilian technology.

One of these companies, Morbach, now seems moribund, at least in this product area, but the other, BIOMAX, continues to operate successfully. It was set up in 1984, essentially as a split from HANSA, and has since sold 45 units with another 5 or 6 on order.

The initial bias towards rice-mills has now swung to their installation in wood factories and sawmills with occasional sales to other agro-residue producers such as coffee mills.

The bulk of the 200 or so machines installed in Brazil since 1980 are said to be still operational, a claim made by BIOMAX who make some efforts to buy back machines if they are not used and resell them.

All the machines installed appear to be conventional mechanical-piston units. No use is made at present of screw machines nor of any plant requiring binders. There are plans to open up plants using the Belgian Biomat machines; these are discussed below.

The main concentration of machines is in the southern states, particularly Rio Grande del Sul, Santa Caterina, Rio de Janeiro, Sao Paulo and Parana. The huge forest-covered states of the north have hardly any machines though BIOMAX has recently sold two units to a sawmill in Manaus in the Amazon area. This regional coverage may, in part, reflect the commercial bases of the plant manufacturers, which were all in the far south in Rio Grande del Sul, rather than the actual pattern of residue availability.

Case studies

Origin of plants

Three kinds of briquetting operation exist or are planned in Brazil; they are, in a sense, natural developments from each other.

The first, and much the most common, operation is the installation of one or two briquetting machines at the point of arising of the residue, usually wood-waste or sawdust, less commonly rice-husks. The machines are operated by the plant owners who also sell the briquettes to nearby factories.

The motivation for setting up these plants appears to have been a combination of solving a waste-disposal problem and making some additional revenue. The former issue does seem to have been irksome rather than pressing, but the ease of marketing briquettes seems to have persuaded many firms to move from dumping their waste.

In fact, the revenue from marketing briquettes is a small part of their total sales and they seem less than dynamic in maximising their potential profit. This has led to the development of a second type of operation, who are essentially briquette producers rather than waste-disposal units of much larger companies.

It is not known how many of these companies exist in Brazil, certainly three were identified and two were either visited or interviewed on the telephone. These companies market briquettes made in one of four ways. They may buy residues from various sources and transport them to their own machines; they may own and operate a machine adjacent to a residue source and, in effect, act as their on-site waste-disposal service; they may purchase briquettes made by another plant and resell them; they may operate an on-site plant owned by the factory and sell the products with the factory owners levying a fee for use of their machine and for supply of wastes.

An operation of this kind works on fairly small profit margins; their principal concern is to maximise the throughput of all the machines they operate. The owners of these companies are entrepreneurs sometimes with wide horizons. Since completing the interviews for this report in 1988, we have been contacted by two Brazilian companies interested in selling briquettes in Europe.

The third type of plant is, as yet, only a planning exercise though the people concerned were confident that two or three projects will be under way in 1990.

The broad idea of this third type is to set up a large briquetting plant with 10-20 machines in an area which produces a lot of residues but has little or no fuel consumers. A typical area would be Parana state in Brazil which has a large number of sawmills and is about 600 km from the big markets of Sao Paula. The residue on which they are concentrating is wood, though they have an interest in other agro-residues. The size of the plants would be 50-100 000 tonnes of briquettes annually. These plants would be set up as turn-key operations funded by the machine manufacturer and, possibly, the regional government. At the moment, three projects are being discussed in Brazil and two in Argentina.

The economics of plants like these is very dependent upon residue costs and market prices and these can vary widely. In broad terms, they were expecting to pay 23 US$/tonne for sawdust, about 2528 US$/tonne in conversion costs and to sell the briquettes for about 80 US$/tonne in Sao Paulo.

The types of operational plant discussed here are all privately-funded operations with no form of state subsidy. There may be some regional government participation in the large briquetting projects but they would be expected to operate on a fully commercial basis.

Type machine

All the plants visited use mechanical piston machines made either by BIOMAX or HANSA. No problems were reported in their functioning; the machines appeared to operate reliably for at least two shifts per day. In one machine, some faulty welds had appeared in the feed hacker but these did not pose any fundamental problem.

It was normal for the fuel to be passed through a chipping mill (a hacker) before going to the feed silo. The main issue with preparing the feed stock seemed to be avoiding tramp metal such as nails or bolts which could occur in the residues from wood processing. The machine appeared to be reasonably resilient to such metal. It was reported that nails and small sheet metal clippings up to about one centimetre would pass through into the briquettes.

Residues used

The only plant visited which used an agroresidue was at a rice-mill. All the other plants used wood wastes, that is a mixture of sawdust and small wood chippings and offcuts.

The rice-husk plant had not proved successful because of marketing problems. The high ash content of the briquettes had proved a barrier to sales. In recent months the plant had operated intermittently using wood wastes from plants in the area.

The other plants visited were all wood processors not sawmills, as the states of Rio Grande del Sul and Sao Paulo which were visited do not have large forestry industries. They do have a large number of furniture and other kinds of wood factory and these were the main centres of briquetting.

The wood residues contained some pieces up to ten centimetres or more wide and the feed had to be passed through a hacker to reduce the fuel size to below about one centimetre. No problems of moisture content were found.

The plants with in-house machines did not price their residues but external agents had to purchase wood-wastes. There is not any systematic alternative market for their wastes so the prices charged seem to vary greatly from place to place.

One plant in Rio Grande del Sul was buying sawdust from a cellulose maker, which gave a rather wet residue, for US$10 for a 3.5-tonne truck load. In Sao Paulo state, wood chippings and offcuts cost about 5 US$/tonne when literally pushed out of the factory door into the machine space whilst the project-planners for the large up-country plants believed that they could buy sawdust for 23 US$/tonne. None of these situations could be considered as representing prices formed in a competitive market. They seemed to represent some view of a fair price by the waste producer.

Various agro-residues had been tried for briquetting but, up to now, had not proved popular. Only rice-husks had been tried in any quantity and ash problems had inhibited the marketing of the briquettes.

The failure of briquetting to spread into more general agro-residue was not entirely clear. Some had alternative uses. Coffee husk was said to be used as a soil conditioner whilst rice-husks were used for bedding chickens. However, the most obvious area of failure is bagasse which is available in huge quantities but for which briquetting is not used. As noted above, most bagasse is consumed in the mills and alcohol plants but Brazilian sugar-cane production is so huge that several million tonnes of bagasse remain unused after direct sugar-processing use.

The main sugar-producers association, COPERSUGAR, had tried to briquette bagasse, using a HANSA machine, but with only limited success. The main problems were, first, that the high residual moisture content (up to 50%) meant that the drying costs required for briquetting made the economics doubtful. In addition, the voluminous nature of the feedstock caused the output of the machine to be much less than its rating - only 300 kg/in was obtained from a machine claimed to produce 1 200 kg/in from wood-waste. Even at this rate, the screw-feeder tended to jam.

It is possible that both these problems could be overcome but, for the moment, utilisation of bagasse has proceeded in other, divergent directions.

It is consumed in large quantities without treatment or loosely baled. Brazilian lorries are very large and it was reported that 25 tonnes of bagasse could be carried without resort to compression. A number of factories, notably in the food sector, had installed special boilers to burn raw bagasse, partly in suspension and partly on a grate. In Sao Paulo, for example, the large Nestle factory has a boiler designed by the Swiss company, Voight.

Some trials by COPERSUGAR on baling bagasse using cotton-baling machinery had proved successful, raising the density from about 120 kg/m³ to about 370 kg/m³. Various improvements had been made to assist the drying of the bales by natural heat to about 20%. A company, Bagaten, has been set up to market the bales in the Sao Paulo area.

This level of bulk density approaches that of briquettes so any potential transport savings for briquettes as against bales would be small. The key problem for bales is undoubtedly finding a combustor that will take them. The very large quantities of bagasse available appears to have prompted enough companies to make the necessary capital investment.

The second approach has been to find outlets for bagasse in higher-value markets, notably paper production and animal feed. In this latter market, the bagasse is pelletised, a process in which COPERSUGAR have found no technical problems. The power costs of pelletising make it unattractive for fuel production but animal feed is a higher price outlet and can justify the cost.

A rather more unusual market is the sales by Bagaten of baled bagasse to Germany for use as a packing in car doors.

However, despite these various bagasse uses, there is still a surplus, particularly outside Sao Paulo state. For example, 400 thousand tonnes of waste were reported to arise around Campos in Rio de Janeiro state. This surplus is likely to increase if sugar and alcohol mills convert to gas to cut air pollution or if they install more efficient boiler plant. In principle, they require far less bagasse than they actually consume.

It is possible that briquetting could still find applications in bagasse. The one trial carried out does not seem to exhaust the possibilities and the transport costs for both raw and baled bagasse seem to limit their use to about 150 km from production.

Markets

All the markets for briquettes were in factories with wood-burning boilers. There are a large number of such installations and some have modern boilers installed after the 1974 oil-price rises. They may consume large volumes of wood; one plant was mentioned which took 15,000 tonnes weekly, and there is no problem in finding outlets.

Wood-based briquettes burn well in such boilers. In fact, the only problem is that they may burn too fiercely if derived, as in one plant, from the best tropical hardwood. Rice-based briquettes have an ash problem, both in disposal and in the fact that the ash is reported to form a hard shell which inhibits combustion.

There are a number of difficulties with wood supply to industry, not so much in its availability but in the unregulated nature of the trade. A good deal of it is said to be 'illegal', which means cut against deforestation laws or traded without payment of taxes rather than cut from land without the landowner's permission. This gives wood supply a problematic character; it contains unknown amounts of moisture and is often sold by volume straight from the lorry. This latter practice gives rise to constant cheating with irregular packing in the inside of the load.

Briquettes can be sold as a uniform and reliable fuel, sold by weight and of necessity containing only a small amount of moisture. It was claimed that because of this, briquettes could command a price premium over fuelwood.

There was considerable variation in the prices quoted for both briquettes and wood. One reason for this is regional variation but a more likely factor is the failure of some operations, particularly chose for whom briquettes were of small commercial interest, to re-price their product very often. Inflation in Brazil is currency in double figures per month so such failures can rapidly lead to price distortions. It was noticeable that the briquetters who made a living solely out of the single product were much more aware of the need to adjust prices. They used either an oil-price index or one related to a notional fixed price currency whose value relative to the cruzado is published each month.

In general wood-based briquettes were sold well above the tonnage price of fuelwood; factors of about 50% were not uncommon. This premium was based upon the different moisture contents and on the consistent quality of briquettes. Prices of between US$24 and US$40/tonne were being charged. The lowest prices were in the south where wood prices seemed to be lower. Comparative prices quoted were:

With these prices as markers, a selling price of 27 US$/tonne was quoted. Another source in Rio Grande del Sul quoted a selling price of 37 US$/tonne for briquettes compared with a wood price of 10 US$/m³.

In general, pricing was undertaken above wood and below oil, though, in recent months, some prices suggested that the oil price had fallen below the wood price in Sao Paula.

The pricing situation can be summarised as somewhat confusing, a reaction shared by some Brazilians who find the need to be constantly repricing their goods rather a chore. However, it did seem that there was a reasonable premium to be obtained selling wood briquettes though less so with a rice-husk product.

Conclusions

Briquetting in Brazil has found a commercial niche in which to operate albeit a small one. Three factors have contributed to this. First, the switch to biofuels of various types has opened a big potential market in the industrial sector for a consistent wood fuel substitute. Second, there is a dynamic domestic plant-manufacturer who sells reliable machines at low prices and is available for installation and commissioning. Third, there is a big supply of a convenient raw material, wood wastes, which have little alternative use as they are inconvenient to transport.

These advantages make Brazil probably the most propitious country in the world in which to undertake briquetting. In the future, the spread of briquetting into larger plants located in the primary wood producing regions and into other raw materials will demonstrate whether or not it has a future as other than a small speciality fuel.

Chapter 15.Briquetting in India

This section is based upon a visit made to India in June, 1987 during which time three briquetting plants and one manufacturer were visited. We also attended a Workshop on Biomass Conversion Technologies held at the Engineering Staff College in Hyderabad. Thanks are due to all the people who helped with this visit; they are too many to list by name.

Energy context

India is a country with a very large and diverse energy economy encompassing reliance upon crude biomass combustion, particularly in rural households, as well as advanced power-generation and hydrocarbon utilisation. The size and diversity of the country make generalizations difficult as well as potentially misleading. However there are four general factors which make India a very interesting country for analysing the use of agro-residue briquetting.

First, it already has a very great reliance upon solid fuels of various kinds. This is generally true of rural households and small industry, which burn not only firewood but also crude agro-residues and dung-cake. In addition to this, there is considerable use of fuelwood in urban areas and, in industry, the main fuel is coal, often high-ash coal. There is some use made of coal in the household sector, usually in the form of smokeless briquettes but the most important households fuels, apart from biomass, are kerosene or gas. Thus, in principle, there already exist a range of existing markets in which briquettes could be sold as direct substitutes in existing appliances.

Second, its major indigenous fossil fuel is coal; liquid and gaseous hydrocarbons are found only in limited quantities. There is therefore little prospect of any cheap indigenous fuel such as natural gas or LPG emerging as the major fuel of choice in households and industry. Indian economic policy has always placed great emphasis upon self-sufficiency so, although this has changed somewhat in recent years, there is only limited scope for increased hydrocarbon use outside the transport sector. Indian coal is abundant, though often of poor quality with a high ash content. However production bottlenecks and the increasing demands of the power industry has meant that it has often been in short supply to industrial users.

Third, it has a very large agricultural industry which includes a big commercial sector processing crops for sale. This means that agro-residues are likely to arise in sufficient quantities to provide the basis for briquetting at all possible scales of production from village to industrial levels. Commercial forestry is confined to a few, rather remote areas so the utilisation of wood residues may not be so favourable. However, in recent years there has been some investment in plantation fuelwood forests which may, in the future, provide a source of wood residues.

Fourth, it has a well-developed mechanical engineering industry which is capable of the design as well as manufacture of briquetting plant of all types. Domestic industry is highly protected so briquetting machinery manufacturers are able to dominate the market.

All this means that briquetting should have a sound basis from which to develop.

Availability of residue

There is little doubt that a very large volume of agro-residues arise in India; one estimate is that 200 million tonnes come from all sources. A considerable amount of this is wasted - the same source suggests that 40 million tonnes is burnt in the fields but much is already utilised. Barnard and Kristoferson in their survey of world agro-residue use, (Barnard and Kristoferson, 1985) estimate that 40 million tonnes are burnt in India directly for fuel. This may be compared with their figure of 133 million tonnes of fuelwood and 73 million tonnes of dungcake used as fuel. Residues are clearly already used to a considerable degree, largely by the rural poor.

Apart from these global estimates, there is little good information about how and where crop residues arise and are used. However, discussions in various parts of India with biomass users suggest that the pattern of production and use has changed quite sharply in the past few years. This is particularly true of rice-husk, which is a major residue arising in all parts of the country, but is also relevant to other types of residues such as groundnut shells.

Until the end of the 70s, agro-residues were utilised, if at all, by the rural poor burning residues collected locally usually at little or no cost. It was reported to us that rice-mills at this time regarded husk essentially as a waste and were happy for it to be taken free of charge.

The big rises in fuel prices following the 1979, oil-price rises, stimulated the interest of industrial concerns in the use of low-cost residues in their boilers. The greater use of high-yielding rice varieties also appears to have increased the use of centralised rice-milling which, in turn, increased the interest of industrial fuel users looking for relatively large volumes of residue. The result of this has been that rice-husk, together with other residues, is no longer a free waste but is a marketable commodity.

As recently as 1984, the price of rice-husk was below 100 R/tonne (7.7 US$/tonne) in most places and could be as low as 25 it/tonne; it is now commonly above 200 it/tonne with some seasonal variation. At one briquetting plant visited in southern India, the price of husk had doubled in the past year. At these prices, it was reported that husk, as well as other residues, were readily available throughout most of the year.

This commercialisation of residues in India has two broad consequences for the briquetting industry.

First, and most obviously, briquetting cannot be regarded as a way of utilising wastes which would otherwise be burnt or dumped. It is one of a number of potential channels of utilisation in which it competes with regard to the ultimate value of the product it produces. The very fact that the residues are purchased at rather high prices means that the product cannot be cheap and cannot therefore be regarded as a way of providing fuel to the rural poor dispossessed of free fuelwood or agro-residues. The converse of this is that briquetting in such a situation does not deprive the poor of a crude waste which they would otherwise utilise directly; removal of wastes from the sphere of local auto-collection and consumption has already proceeded to a considerable extent.

Second, the fact that residues already command a high price for other fuel uses means that briquettes have to find particular market niches in order to compete with direct combustion. In particular it throws great emphasis upon the transport costs of raw as compared with briquetted material.

In summary; agro-residues are plentifully available in India - at a price.

Background

Interest in briquetting appears to have emerged at the end of the 70s. One of the major manufacturers of piston-presses began production under licence in 1982 following survey work conducted in the previous few years. The main Indian design, the pyrolysis method developed at the Indian Institute of Technology (IIT), was also brought to the market at about this time. The briquettes produced by the two systems are quite different and they are aimed, in principle, at different markets; the IIT process for the household sector and the other type for the industrial market.

There appears to have been a small boom in such plants, particularly based upon the pyrolysis technology, with several dozen plants set up in the first half of the 80s. Many of these plants were small-scale entrepreneurial endeavours and few survived their early problems. These problems are discussed in more detail below but they concerned both the technology and the markets for the briquettes. It is not clear how many plants were set up as no statistics were collected, though in mid-1985, it was possible to list 23 plants based upon the IIT technology alone as well as 10 manufacturers of various types of plant. By mid-1987, only 2 of the plants were known to operate though at least 2 manufacturers were said to be still in business.

This initial burst of enterprise appears to have been based upon very over-sold prospects of quick profits. By 1987, the number of plants were considerably reduced but, as will be discussed below, those remaining considered their prospects to be reasonably good. Plants in Bombay and Pondicherry based upon piston machines were reported to be expanding from their initial size and one or two new plants were opening.

Case studies

In mid-1987, we visited 3 briquetting plants and obtained detailed information about their activities. This section summarises this information and also comments upon it in the general context of Indian briquetting. We concentrate on the following issues:

• the circumstances under which the plants were set up;
• the equipment used and its general success;
• the agro-residues used;
• the markets for the product;

Plant origins

Two of the plants were in northern India in Uttar Pradesh, one of the main rice areas, whilst the third was located near to Hyderabad in southern India. The main residue in each case was rice-husk though various additional residues had been investigated.

Each was founded under much the same circumstances: an individual interested in finding a new business activity saw briquetting machines in operation at a trade fair or exhibition and set up a plant using their own private resources. In two cases, the founder had an engineering background, in the other, he was a practicing lawyer.

All those concerned can best be described as enthusiastic entrepreneurs; people who wanted to make a business success of the plants but who also had a particular interest in the use of wastes to make a socially valuable product. It is clear that such enthusiasm was necessary to see them through the initial difficulties.

In all cases, the investment finance was private; either their own resources or a commercial loan from a bank. No government support or subsidy was available; indeed it a source of complaint that even the normal tax reliefs granted to new business had proved difficult to obtain The loans were made at normal commercial rates; one plant quoted a level of 13.5 %.

The plants were located in a variety of locations; from a semi-urban area to one about 3 kilometres from a town but close to a group of rice-mills to a fully rural plant about 30 kilometres from Hyderabad.

Equipment used

Two types of technology were in use at the three plants and a third was being evaluated at one plant. Two plants used mechanical piston units bought from Indian manufacturers whilst the third used the pyrolysis technology developed in an Indian research institute. A screw-press device with a heated die was being tested at the plant near Hyderabad; it was based upon a design developed by the plant owner.

The piston machines had quite different initial operating performance; one plant reported no problems in startup whilst the other had taken over a year to obtain satisfactory performance. This appeared to be directly related to the relationship with the manufacturer who, in one case, had offered considerable help in commissioning whilst in the other, the owner had been left effectively to his own devices.

This may have been a function of distance; in the best case, the manufacturer's plant was within a days drive, in the other, it was rather distant.

It was also likely that the different startup problems were related to the care of the initial installation. It is clear that attention has to be paid to the provision of good level foundations in a properly laid-out building. It is also important that the manufacturer should have direct experience of the residue concerned and should be able to provide initial assistance with matters such as die size and the quality of the residue used. The machines used in India are of a simple, fixed die-size design so the initial sizing is critical to success.

The plant which had experienced start-up problems had been left very much on its own. After surmounting the initial problems, the owner appeared to have set up a virtually self-supporting operation as he had arranged for replacement dies to be machined in a local plant to his own specifications. This is an interesting example of how briquetting technology can be adapted to particular local circumstances but it is not a good recipe for initial commercial success.

The two plants described above each used a standard piston briquetter. The plant based on pyrolysis technology had experienced a large number of technical problems, particularly in the pyrolysis and dryer stages. The process first chars rice-husk using heat generated by combusting the gases given of in the pyrolysis process. There had been corrosion from these gases and the accompanying liquids which necessitated replacement of some parts with a different material whilst the dryer (based upon waste-heat from the pyrolyser) was under-sized. Sun-drying of the product was used as an alternative.

The briquetting part of the process, which compacted carbonised rice-husk with a molasses binder, worked satisfactorily. it was essentially a multiple-hole extrusion press with very little pressure developed. The owner had received little support from the manufacturer and had made many of his own modifications including having replacement extruder made locally. In general, the process seemed to have been brought to the market before it was adequately engineered and tested.

Residues used

In each case, the only biomass used in significant quantities was rice-husk; in the two plants in Uttar Pradesh it was the only residue, except for some small quantities of sawdust in one plant. The Hyderabad plant received other residues in small quantities including some waste rice-husk from a brass plant where husk is used for polishing the metal goods. (This must set a record for efficient use of wastes; the use of waste waste). Other residues included some from an oil-mill and "anything else" that could be found.

The Uttar Pradesh plants were both located in major rice-growing areas by towns with a concentration of rice-mills. These mostly had a milling capacity of upwards of 100 tonnes/day so there was no great problem in finding material for a briquetting plant consuming, at most, 10-15 tonnes/day. It was reported that husk was freely available at a price which was seasonable variable from about 150-180 R/tonne at harvest to as much as 250/260 R/tonne.

The Hyderabad plant was not in a particularly high-yielding agricultural area and bought residues from a much wider range, sometimes more than 100 km. However, although the operator was forced to look around much more for residues, rice-husk still formed the basic input. It was reported to us that there were large and expanding briquetting plants in Pondicherry and Bombay which used a wider range of residues, possible because they were based near large cities. The great concentration on rice-husk was still striking, however, particularly as rice-husk, because of its high ash content, is far from an ideal residue. It is possible that other residues might be available for use. One plant had made briquettes using a mixture of husk and sawdust which burnt well but the sawdust was in short supply.

Markets

The markets for the three plants split neatly into two depending upon the briquetting process used.

The piston-machines produced large (up to 9 cm diameter) briquettes which could only be burnt effectively in industrial or large commercial boilers. Their market was as a coal replacement in industrial boilers plus a small market in establishments such as large schools.

Marketing was not a straightforward matter of price competition however as the high ash content of rice-husk meant that only certain types of combustion chamber were suitable. The fixed-grate type of furnace tended to become clogged with ash and the most ready sale was to step-furnaces in which the ash was pushed down through the combustion zone. This difficulty arose despite the fact that the competitive fuel in these boilers is coal which, in India, often has a high ash content. The type of ash from rice-husk is, however prone to setting into a hard crust which may lead to combustion problems.

In Brazil, it was reported that the difficulty of burning rice-husk briquettes in wood-burning boilers had led, in at least one case, to its abandonment as a briquetting residue. The problem is not so extreme in India as high-ash coal is the target fuel, but it does restrict the range of possible appliances.

The reason for the steady rise in the price of rice-husk has been the adoption of husk for direct combustion in some industrial plants. This has probably required some investment in changing the combustion system or entailed a loss of efficiency but, given the fact of such demand, it has proved difficult for briquettes to compete directly with such use. The price required to make a return on investment is at least 550-600 it/tonne and rice-husk even at 250 R/tonne looks a better fuel for those units which can consume it. (Briquettes with sawdust can command a higher price, about 900 it/tonne but the residue is much more expensive and in short supply).

This has meant that the Uttar Pradesh piston-plant sends most of its output of 4000 tonnes/year as far away as Agra and Delhi, a distance of 200-300 km. at a transport cost of 100-120 it/tonne. In Delhi, it was reported that wood cost 700-900 it/tonne and coal, 1 000-1 400 it/tonne whilst rice-husk was not available in any quantity.

In essence therefore, the Uttar Pradesh plant is taking residue from an area with rather little industry but a lot of agriculture to one which is the reverse; the profit lies in the lower transport cost and greater handleability of briquettes with respect to the residue and the higher cost of fuel in the target area. This marketing approach was not without costs; the plant had a partner in Delhi whose job was marketing the product.

The Hydererabad plant appeared to have less of a problem competing with the direct combustion of rice-husk, perhaps because the area did not have a great husk surplus but it still had to search around for suitable combustion appliances. Again, the product was transported to customers over distances sometimes greater than 100 km.

The second plant in Uttar Pradesh used the very different pyrolysis technology based upon a design developed at IIT in Delhi.

This process carbonises rice-husk by heating in the absence of air to produce a char. The char is then mixed with a binder, usually molasses, (some clay is also added, to improve the combustion properties) and then passed through a pressure extrusion process to produce slightly damp cylindrical briquettes. These have to be dried before use; the plant has a dryer installed which uses waste gases from the pyrolysis unit. This is under-sized and air-drying is used to supplement the mechanical dryer. Strictly speaking it is doubtful whether any significant "densification" occurs in the extrusion stage. Certainly there is no chemical action analogous to the lignin release which occurs in the production of briquettes from an untreated residue. However, the product is conventionally called a briquette.

The market envisaged for this process appears to have always been the household sector. Char-based briquettes have been seen as smokeless replacement for wood or charcoal burning in the home. In practice, pure rice-char briquettes have proved extremely difficult to market. A number of objections were raised by domestic customers including the too-rapid burning time (45 minutes) compared with charcoal or smokeless coal briquettes, a sweet smell of molasses, and, in the cases of small commercial premises such as teashops, the key fact that coal costs the same and burns better.

As a result of these complaints and despite active marketing, the pure rice briquettes are no longer marketed to urban consumers in the medium-sized town (Bareilly) where the plant is located. Sales are made to households in the hill areas. Here there is a need for a winter heating fuel and the briquettes are used as a charcoal substitute in room-heaters. Some sales were also made to small industries such as camphor burning but the ash content proved a drawback.

The plant-owner has attempted to improve the quality of the briquettes by producing a version made with 50% rice-char and 50% coal-breeze. This latter, a fine coal dust, is obtained from a steelworks in the region. Coal breeze is expensive, 800 it/tonne, but its use in briquettes enables a marketable product to be made which is sold to retailers for 950 it/tonne as against 850 R/tonne for the pure rice-char product.

Pure coal-breeze briquettes are also made in a simple pressing machine in which molasses are also used as a binder. The resulting briquettes are ovoids and readily saleable at 1100 R/tonne to teashops and small restaurants as a semi-smokeless fuel. There is almost certainly a greater profit margin in pure coal briquettes which require very little investment or operating costs. The raw material is limited however and the owner is committed to the production of rice-based fuel in which, quite rightly, he sees a much greater potential.

The dilemma of marketing this product is clear. The target market is very large but composed of a large number of individual consumers who are not likely to obtain all their fuel in the form of briquettes nor to change either their cooking-appliances or expectations of the fuel. The product is not cheap. The plant is labour intensive employing 9 men per shift, which adds about 170 it/tonne to the costs of the briquettes, whilst the raw material costs up to 250 it/tonne. It is therefore difficult to compete by cutting prices very much in comparison with other fuels whilst the product offers no great advantage over coal or wood.

One market niche has been found, the hill households, and the owner is searching for others. But whilst the main product is confined to a coal/rice mixture which offers barely any price markup over the raw material cost of the coal, it is clear that the commercial future of the plant will be difficult.

The owner accepts this; his continued commitment to the plant seems to be as much a consequence of his social belief in the future of such fuels than any hardheaded commercial judgement.

Plant manufacturers

There have been a number of Indian manufacturers of briquetting plant of various kinds though it is not clear how many of them have ever been- or are now active. One manufacturer was visited; Ameteep Engineering, which produces conventional piston machines originally built under licence from Hausmann though this has now lapsed.

The firm has been reasonably successful selling 6 machines since production started in 1983 with 3 more on order in mid-87. This is however only a very small part of their total business, the manufacture of power presses and shears for the metal industry, and certainly is a smaller number than their original hopes.

The technical features of the machine are basically of conventional form though it has had a number of modifications for Indian conditions. These were described as essentially involving simplification of the original design, echoing other comments made elsewhere that European and North American machines tend to be over-engineered for developing countries. It is not entirely clear what this means but appears to relate to the perceived need in Western designs for the machine to run unattended for long periods. It is also not clear too what extent such engineering practice contributes to the high cost of the Western plant. Certainly Ameteep claim to be able to produce at substantially below quoted European prices.

The machines seen in operation worked well and the only customer of Ameteep interviewed said that the after-sales service provided was good with help given to training plant engineers and in commissioning the machine.

Ameteep acted purely as manufacturers; they have no ambition to set up briquetting plants themselves and they rely heavily on the entrepreneurial aspirations of others. They have developed the machine design, starting from the Hausmann licence, entirely on their own resources, illustrating once again the very independent way in which residue briquetting has developed in India. Unlike the European and American situations where considerable subsidies of various kinds have been given to both machinery producers and development plants, there is no evidence of any subsidy or development funding being made available in India.

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