Bamboo ang pulp making

Media

Part of Panorama

Title: Bamboo ang pulp making
Language: English
Source: Panorama XIV (5) May 1962
Rights
Fulltext: Bamboo belongs to the same family as corn, wheat, and other grasses. There are about 700 known species of bamboo all over the world. Thirty of these are found growing in the Philippines. Bamboo varies in height from 15 cm. to over 30 meters at maturity. This perennial monocotyledonous plant can thrive at temperatures rang ing from 9 to 36 degrees Cen tigrade and has been found at altitudes as high as 3700 me ters above sea level as in South America. BAMBOO an(j pulp making As a raw material for pulp and papermaking, bamboo has several advantages. It is re latively clean and, unlike wood, does not require bark ing. Its fibers are generally longer than those of other grasses and hardwoods. Fi bers of some bamboo species have been found to be as long as those of the conifers, if not longer. Generally, bamboo is easy to propagate. It grows rapid ly. In India it is exploitable from 6 to 12 years after plant ing and at 3- to 4-year har vesting cycles thereafter. Un fortunately, reliable informa tion on sustained yields of Philippine species are not yet May 1962 63 available. It is likely that climatic and other environ mental factors in the Philip pines are similar to those in many bamboo areas of India. Hence, there is every reason to believe that Philippine bambos behave similarly. It is encouraging to note that in Burma, India, and Pakistan sustained yields of 1.6 to 9.1 metric tons of dry bamboo per hectare per year have been reported. In the United States and Japan it has been noted that the annual yield of pulp per acre from bamboo is as much as 5.5 to 7 times greater than that for pine pulpwood which, in addition, DR. JOSE P. LAUREL AND . . manhood and self-respect are literally being torn to shreds by helplessness and despair.” In the face of these realities, the development effort can not but be a continuing impera tive. I have had occasion to state, without wishing to be categorical, that the only ef fective formula there is for eradicating poverty, for ad vancing the standard of living of the people, for carrying out the precept of the Constitution that social justice be promoted to insure their well-being and economic security, is produc tion. And it must be produc tion that should outstrip the growth as well as the increastakes a much longer time to grow before it can be harves ted. At present, bamboo is the principal raw material of the pulp and paper industry in In dia and it is a potential raw material in Burma. The an nual consumption in India is about 400,000 tons. It is also used for the same purpose in Thailand, Japan, Taiwan, and Pakistan. In India, clear cutting or cutting of all the culms in a clump or in an area was found to be destructive to the health of the plant and led to a deterioration in yield. On the other hand, selective (Continued from page 13) ing needs of the growing po pulation. Production is the end result of the coordination of a num ber of factors. These are la bor, capital, entrepreneur ship, and the resources of na ture. The instrumentality that coordinates these fac tors and lines them up toge ther into a driving force that pushes the productive power forward is business enterprise. Without business enterprise production is an impossibility. Business enterprise, however, inevitably must operate under systems of governmental, monetary, fiscal and other sta tutory rules and regulations. 64 Panorama cutting which is now prac ticed there and in Pakistan requires the cutting of only the mature culms in cycles of 3 to 4 years to ensure high sustained yield. In this re gard, felling rules prescribe the number of culms to be cut, when and how the cut ting is to be done. The harvested bamboo culms are brought to the pulp mill either by rail, trucks, or by floating in rivers. PREPARATION OF RAW MATERIALS Crushers The crushers used are simi lar to those used in sugar mills. The culms are split and broken by feeding them through pairs of rolls with progressively narrowing clear ances and grooves. Chippers Modern high speed chippers having 5 to 10 knives, like those used for pulpwood, are being used in recently con structed mills. Some chippers have provisions for holding the culms against the chip per knives. In some mills combinations of crushers and chippers are used. The culms are first lightly crushed and then chip ped. These rules and regulations can help the productive pro cesses to move ahead. They can also hold them back and obstruct them. Rules and reg ulations obstruct business en terprise when they curtail the full and beneficial utilization of the resources constituting the tools and factors of pro duction. When they do, they obstruct not business enter prise alone; they obstruct pro duction itself. When produc tion is obstructed, the effort to eradicate poverty, to pro vide fuller employment oppor tunities, to raise the standard of living of the people, to pro mote social justice, is also ob structed. For the past twelve years until a little over a month ago, business enterprise had been operated under a system of controls, particularly in the matter of accounting for the foreign exchange proceeds from exports and in having all imports and other commit ments to pay foreign exchange abroad licensed. The latter especially was particularly shackled by diverse regula tions governing the importa tion of commodities for con sumption or production; for the purchase of plant machin eries, spare parts or raw ma terials; for the acquisition of essential or luxury or unclassi fied articles; and for other May 1962 65 After crushing and/or chip ping, the chips are screened and the fines discarded. The oversized pieces are reduced to the proper size by passing through hammermills, disinte grators, and other similar de vices. The screened pieces go to the bins, silos, or direct to the digesters. The crusher produces sub divided pieces which are very easily penetrated by cooking liquor. However, the bulk of pieces produced in crushers is greater than that of an equal weight of chips produced in chippers. The material pro duced in the chippers contains less fines and the chips are of more uniform length (1 to 1-1/2 inches) than those pro duced in the crushers. The crushed material consists of irregular-sized pieces, some of which are as long as 5 inches. Because of the high silica con tent of bamboos, which easily dulls the knives, frequent re grinding or replacement of the chipper knives is>required. PULPING METHODS The sulfate and sulfite pro cesses are employed in bam boo pulp mills today. The soda process is also suitable for bamboo, but the pulp is purposes. Whether a business enterprise may go into one kind of business or another, or whether it may or may not be permitted to go into busi ness at all, depended also upon other kinds of regulations,— all of which, as the regulatory and licensing authorities were becoming bolder, were becom ing administered also accord ing to their personal whims and caprices, and, eventually, a time arrived when licenses, if issued at all, could be had only against questionable con siderations. From the economic stand point, the control system was showing signs of having out lived its usefulness during the last few years. Conceived to conserve the exchange re serves of the country, we had less than $100 million in re serves in 1961 when there was $300 million in 1950. Adopted as a tool of managed economy to accelerate and increase ag ricultural, and expand and diversify industrial, produc tion, the country found that the yearly increase of its gross national product had dwindled bv 1960 to 2.6% compared to the 6.9% average of 1950 to 1955 and the 4.4% from 1956 to 1959, with 1961 making no better showing than 1960. The Governor of the Central Bank is authority for the statement that “our export trade, long suffering from lack of incen66 Panorama inferior in quality in most respects to that produced by the sulfate process. Experi ments in mechanical grinding, neutral sulfite, cold soda se michemical pulping, and con tinuous kraft digestions have been done on bomboo, but these are not yet practiced on a commercial scale. Sulfate method The sulfate method is the most widely used in bamboo pulping because it readily pro duces acceptable pulp from mixtures of species. The pulp is stronger than that made by other processes and the che mical recovery system is eftive due to the administrative ly fixed rate of P2.00 to $1.00, did riot respond as favorably as hoped to the first stages of gradual decontrol which af forded higher exchange rates. Instead, it was caught in the grip of speculation at home while plagued with deteriorat ing market prices for our pro ducts abroad. Our export trade dropped by 10% in 1961, while imports increased by 17%. Investments slowed down, financial resources were frozen in inventories, ag ricultural and manufacturing production slackened, and mining suffered a reduction in output”. With extraordinary courage and vigor, and animated by a ficient and leliable. There are two methods of sulfate digestions, namely, the fractional or two-stage method and the single-stage method. The fractional method is based on the studies of Raitt at the Indian Forest Research Institute. The first stage of digestion uses the spent liquor from the second stage of a previous digestion. Raitt.’s process is carried out at a temperature of about 108 to 115 degrees Centigrade for two hours using about 8.5 per cent active alkali as sodium oxide. During the first stage, resolve to free the economy once and for all of the ple thora of regulations and reg ulatory bodies that were chok ing the national productive ef fort, the new President who took office on December 30, 1961 authorized the promul gation on January 21, 1962 of the decontrol order. At one stroke, almost all licensing re quirements for carrying out foreign exchange transactions were written off the books. This was a most courageous step. Had safeguards against hoarding and consequent run away prices been ineffective, flight of whatever little of the foreign exchange reserves still left could have taken -place. The decontrol system could May 1962 67 the starches and pectins are removed. The black liquor is pumped to the recovery plant at the end of this stage. Sub sequently, fresh liquor con taining active alkali as so dium oxide equivalent to 15.5 percent of the weight of the chips is charged and the cook ing proceeds at 153 to 158 de grees Centigrade for one hour and for two hours more at 140 degrees Centigrade. Deligni fication occurs during this stage. The spent liquor from the second-stage cook is drain ed into the digester of a firststage cook. The pulp obtain ed by this method is easily DR. JOSE P. LAUREL AND . have been utilized by unscru pulous speculators to bring about an economic debacle, even a social upheavel in the country. I must quote again the Gov ernor of the Central Bank on the safeguards taken to insure the success of the decontrol program. “In view of the mass i v e inflationary pressures which had been built up last year by prodigal government spending and liberal credit, it was imperative to place some restraint on new monetary creation. Money supply dur ing the one year period ending October, 1961, had expanded by 15%. Such a magnitude of monetary expansion was well bleached by a single hypo chlorite treatment. However, the modern two-stage methods use (1) in the first stage, 2 to 3 percent active alkali as sodium oxide and a cooking time of 2 to 4 hours at 142 to 150 degrees Centigrade and (2) in the second stage, 12 to 13 percent active alkali as so dium oxide and a cooking time of 4 to 4.5 hours at 162 to 170 degrees Centigrade. The use of less complex single-stage cooking methods to produce bleachable pulps is now possible due , to the modern multi-stage bleaching processes. The single-stage above the danger point signi fied in the Central Bank Char ter. Central Bank rediscount ing and lending to private banks had also gone up by nearly 100%. The specific measures taken to counteract these conditions were: (1) the raising of the rediscount rate; (2) the reimposition of redis count quotas on banks; (3) the raising of bank reserve re quirements against demand deposits, and (4) the prescrip tion of time deposits as a con dition for opening import let ters of credit. A stipulation intended to dampen the infla tionary effects of exchange windfalls arising from decon trol requires that 20% of all 68 Panorama sulfate method takes 4 to 5 hours at 165 to 173 degrees Centigrade with 15 to 16 per cent active alkali as sodium oxide. The sulfidity of the cooking liquors used for both single- and two-stage diges tions varies from 10 to 25 percent. Studies in the Philippine Forest Products Research Institute have shown that some Philippine bamboo spe cies such as bolo (Gigantochloa levis), buho (Schizostachyum lumampao), giant bamboo (Gigantochloa aspera), kauayan-kiling (Bambusa vulgaris), kauayan-tinik export proceeds should be turned over to the Central Bank at the official rate of two to one.” The measures taken to free the economy from regimenta tion were a long stride for ward from the regime of gov ernment functionaries dictat ing to their fellow citizens how their business should be conducted or how their con sumption needs should be sa tisfied. It was again Dr. Lau rel who said, “We prefer this type of economy” — he meant free economy — “because both theory and experience tell us that it is the only type that can enable us to preserve our democratic institutions.” Corollary to social justice, (Bambusa blumeana) and yel low bamboo (Bambusa vulga ris var. striata) respond well to the single-stage sulfate me thod using 15.5 percent alkali as sodium oxide with 25 per cent sulfidity, a cooking time of 3 hours, and a miximum temperature of 170 degrees Centigrade. The yields ranged from 40 to 47 percent. Sulfite method A disadvantage of the sul fite process for pulping bam boo is that each species must be cooked separately as diffe rent digestion conditions are required. Of course, more la bor is required in handling another objective of increased production is to lessen if not close the gap between export income and import expendi tures. The long range goal is to develop favorable foreign trade balances, the only way by which the value of the peso in both the domestic and the international markets can be stabilized. Without reaching a settled balanced position in the foreign trade, the ex change value of the peso or the term of its foreign ex change convertibility will al ways be an uncertain, unsta ble rate that will float up and down with the variable waves and troughs of demand and supply of foreign exchange as well as demand and supply of May 1962 69 each species separately in stacking, chipping, etc. The cooking time is much longer than that required by the suf fate processes. Another factor which has hindered its wider use has been the lack of a chemical recovery system. The application of modern re covery systems now available could possibly make this pro cess competitive with the suliate process. The sulfite process is em ployed by only one mill in India. The magnesium-base cooking liquor contains about 1.95 percent free SO2 and 2.3 percent combined SO2. The DR. JOSE P. LAUREL AND . peso to pay for it. Supply of foreign exchange adequate to meet every foreseeable de mand can not be had unless and until the foreign trade is at least balanced, or until we attain what the economists call an equilibrium in the bal ance of payments position. The country can not depend upon stabilization loans all the time. If decontrol had been pro mulgated without the safe guards we have mentioned, and without.a knowledge of the existing situation in the market of essential foodstuffs and other necessities of daily life, the commodity hoarders and price speculators could total sulfur in the liquor is equivalent to about 8.0 to 8.6 percent of the weight of the chips. Cooking takes 19.5 to 20.5 hours and the maximum temperature varies from 155 to 160 degrees Centigrade. Because of the low capacity of this mill it is not eco nomical to recover the chem icals for re-use. BLEACHING Two-stage cooked sulfate pulps are bleached in the mills by two hypochlorite treatments with washing after each treatment. The available chlorine consumption ranges from 7 to 10 percent. have gained dominance of the situation. Prices could have skyrocketed. But because the country had four to five months’ inventories of essen tial commodities on hand, it was calculated that such sup plies were too large for cor nering and hoarding, so that skyrocketing of prices was not likely to take place. Even then, there has still been a notable increase of commodity prices, especially the prices of imported goods. Prices of domestic goods have a way of following sympathe tically the behavior of prices of imported commodities. But such increases as have taken place have largely been a kind 70 Panorama Multi-stage bleaching is used for sulfite and for singlestage sulfate pulps. This con sists of chlorination, caustic extraction, and one or more stages of hypochlorite treat ment, with every stage being followed by washing. Avail able chlorine consumption va ries from 6 to 8 percent. PAPERMAKING The processes and equip ment used in bamboo paperof sounding out by the trad ing elements to see how far the consuming public would follow. After all there is a limit to the capacity of con sumer purchasing power to absorb price increases. To further neutralize the threat of speculation and hoarding, the time deposit re quirements in the opening of import letters of credit cover ing essential consumption and production goods have just been lifted. Thus, another major step has been taken to ease the way of free enter prise. The relief could have been more widespread, how ever, if the importation of all raw materials and spare parts o f existing manufacturing plants were likewise eased. They represent investments that should not be liquidated, sources of employment that should not be emasculated, making are essentially the same as those used for other fibrous materials. Bleached sulfate and sulfite bamboo pulps, either alone or in mix tures with other pulps, are used for making a wide va riety of writing, printing, and wrapping papers, newsprint (as the chemical pulp por tion), and paperboards. Un bleached bamboo pulp is used for paperboards, wrapping, and bag papers. productive facilities contribut ing to the economic advance ment of the country that should not be stultified, even if they pertain to the non-es sential producer category. While easing the way for the importation of essential commodities to replenish di minishing inventories, coun teracting thereby the incipiency of increasing prices be ing generated by imagined scarcities, this relaxation measure poses a new problem. It will create a substantial de mand for foreign exchange which will lower once more the value of the peso. Foreign exchange holders will tend to hold on to their dollars as long as possible and will sell only when no further dollar price advance may be expected. In other words, the floating rate will call again for more pesos to buy one dollar. This, howMay 1962 71
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