2, technical background
China's wheat straw aboundresources has long history with generated by making paper with wheat straws.At present, straw cooking equipment has rotary spherical digester (batch cooking) and transverse tube even to steam the even general soda processes that adopts of steaming of two big classes, and batch cooking employing caustic soda is feared awake method or caustic soda Ya Nafa.Generally do not adopt sulfate process, it is the colloid black liquor that its technology causes final accessory substance, accounts for more than 80% of whole paper-making pollution amount.At present, to be still environmental protection field, the world so far be a great problem of capturing to the pollution sources black liquor of ryegrass pulping.
Traditional rotary spherical digester pulping process generally all is to adopt high-alkali, high temperature, anthraquinone, pulp-making method.In wheat straw dress ball process, though wheat straw is through dedusting and screening, and wheat straw skin and leaf are put into 10% in the whole wheat straw that account in the ball, and skin and leaf are at first cooked under the boiling of high-alkali high temperature, after this being only the wheat straw bar is cooked to become and can be utilized fiber, at this moment become little shape thing in skin and the Ye Zaiqiu, under the effect of spurting, well-done tangerine rod fibers also can be broken more, and then producing a certain amount of superfine fibre, these superfine fibres will enter in the black liquor of discharging together with those skins and leaf.Therefore, produced the too high black liquid of a large amount of COD.And the straw pulp that produces of cooking process pulping process also to have a fiber short, microfibre is too much, becomes tearability, the folding strength of paper poor, problems such as papery embrittlement.
About the improvement of black liquid, no wonder the processing method lignin acidizing separation method used always of people, alkali lignin method and burn Silvola recovery, lignin acidizing separation and alkali lignin dual mode now.Processing cost to black liquor is higher, and enterprise is difficult to bear, and also fundamentally can't resolve pollution problem, has become a kind of stagnant water that can not administer.Burn the history in existing more than 20 year of application of Silvola recovery, as produce 50 tons the paper plant alkali that starts daily and reclaim, must invest 4,500 ten thousand yuan, one-time investment is excessive, and enterprise's standard is to bear.Burn alkali recovery technology and in actual application, still have the difficult problem that can't overcome,, make fouling of evaporator easily, alkali stove atomization badness and blocking pipe and black liquor lance driving device or the like as because silicon content height in the black liquor, viscosity are big.Because above a variety of causes.Cause many enterprises slurrying facility idle in a large number, many wastings of resources, in order to protect environment, our country also has to limit the scale of Straw Pulp development, forces the closure, suspension, merger and conversion of many paper mills, has caused enormous economic loss, makes paper industry move towards low ebb.
3, summary of the invention
Problem in order to solve papermaking serious environment pollution at night and can't thoroughly to effect a radical cure the invention provides a kind of no boiling drug immersion ryegrass pulping technology.Passed through 8 years experimental exploring of thousands of times, developed finally and can under normal temperature, normal pressure, need not boiling and only just can replace traditional boiling can obtain the new technology of wheat straw paper pulp by the chemicals immersion.This technology need not heat and consume fuel in process of production, does not have the pollution of waste water to environment, and characteristics such as technology is simple, production cost is low, and pulp quality is good.Be the paper-making industry of China, particularly medium-sized and small enterprises, created a very space of development.
In wheat straw drug immersion pulping process of the present invention, by chemicals wheat straw fiber has been carried out modification, thereby can improve cellulosic performance effectively, and can produce paper pulp with property.Though the beating degree of infusion method paper pulp is lower than wood pulp, is better than cooking of pulp.This has just illustrated that drug immersion slurrying might replace pulping by cooking technology in the future.
Paper industry is the basic industry of national economy, and China is the country of a poor woods, and timber papermaking only accounts for 12.3%, and the main raw material of papermaking still is the straw pulp fiber.For improving the class of papermaking straw pulp, enlarge the purposes and the effect of straw pulp, it is imperative deeply to reform ryegrass pulping technology, and the modification of straw pulp fiber will be an inexorable trend of improving straw pulp performance.
4, embodiment
No boiling drug immersion ryegrass pulping technology of the present invention, be that the method that adopts no boiling and chemicals to soak is handled wheat straw class paper making raw material production paper making pulp, soaking wheat straw is made up of following materials of weight proportions with the immersion medicine: sulphur 20-50 part, magnesium carbonate 10-30 part, aluminium hydroxide 10-30 part, magnesia 30-60 part;
Weight proportion in the immersion process between wheat straw and the chemicals is: wheat straw: caustic soda: hydrogen peroxide: soak medicine: water=100: 5-15: 1-5: 0.1-1: 60-85.
The raw material preferred weight proportioning of soaking medicine is: sulphur 30-40 part, magnesium carbonate 15-20 part, aluminium hydroxide 15-25 part, magnesia 40-50 part;
Weight proportion in the immersion process between wheat straw and the chemicals is: wheat straw: caustic soda: hydrogen peroxide: soak medicine: water=100: 8-12: 2-3: 0.3-0.6: 70-80.
The optimum feed stock weight proportion that soaks medicine is: 35 parts in sulphur, and 18 parts in magnesium carbonate, 20 parts in aluminium hydroxide, 45 parts in magnesia:
Weight proportion in the immersion process between wheat straw and the chemicals is: wheat straw: caustic soda: hydrogen peroxide: soak medicine: water=100: 10: 2.5: 0.45: 75.
Pulping process is: mix in fermentation vat with immersion medicine, caustic soda, hydrogen peroxide and water in proportion after wheat straw raw material is pulverized and soaked 24 hours, the wheat straw raw material after soaking is washed sieve, removal of impurities and bleaching conventional treatment through defibrination make production cultural paper or high-grade sanitary paper pulp product.
Embodiment
One, ryegrass pulping
1, the pulverizing of wheat straw the wheat straw of discongesting after the removal of impurities is generally the 3-5 centimetre, at this moment wheat straw is softening, and the part of wheat straw joint is not damaged, it is unfavorable that immersion is brought, and the length of joint surpasses one centimeter can not soak, if soak, the pulp hardness that produces is big, fibre bundle keep too much, hemicellulose level is many etc., and disadvantageous heteroproteose cell colony remains in the slurry, paper delivery brings bigger influence to the paper machine.Through soaking and paper machine paper delivery production experiment, the wheat straw of removal of impurities is necessarily discongested, so that reach the requirement of immersion.
To discongesting of wheat straw, mainly be that the wheat straw joint is discongested processing fully, wheat straw joint percentage of damage is reached more than 95%, so just can obtain the paper pulp of quality better.
2, soak in the dress pond
The wheat straw of discongesting is packed in the fermentation vat with transmission device, in proportion various medicines and water are added in the fermentation vat, wheat straw soak time in fermentation vat is 24 hours.The stock quality that soaks is not subjected to Temperature Influence.
Prescription one
Soaking medicine raw material weight proportioning forms: 20 parts in sulphur, 15 parts in magnesium carbonate, 25 parts in aluminium hydroxide, 45 parts in magnesia.
Weight proportion in the immersion process between wheat straw and the chemicals is: wheat straw: caustic soda: hydrogen peroxide: soak medicine: water=100: 10: 3: 0.7: 80.
Prescription two
Soaking medicine raw material weight proportioning forms: 25 parts in sulphur, 20 parts in magnesium carbonate, 30 parts in aluminium hydroxide, 30 parts in magnesia.
Weight proportion in the immersion process between wheat straw and the chemicals is: wheat straw: caustic soda: hydrogen peroxide: soak medicine: water=100: 15: 4: 0.5: 65.
Prescription three
Soaking medicine raw material weight proportioning forms: 25 parts in sulphur, 20 parts in magnesium carbonate, 30 parts in aluminium hydroxide, 30 parts in magnesia;
Weight proportion in the immersion process between wheat straw and the chemicals is: wheat straw: caustic soda: hydrogen peroxide: soak medicine: water=100: 10: 2: 0.3: 60.
3, go out the pond: soaked wheat straw is well-done, moves wheat straw with giant and flows, and directly is extracted in the fiberizer with high density stock pump, carries out paper pulp and discongests, and also can manually go out the pond.
4, defibrination: wheat straw has become the screened stock material fully, reasonable reservation fibre length, and paper pulp has also obtained good branch silk, has improved the quality of Straw Pulp significantly.The paper pulp that refinement is good is pulp product after removal of impurities and bleaching.
Two, cellulose analysis: slightly starch faint yellow, easily bleaching, paper pulp is fineless and smooth, fiber is better.
Brightness of pulp after the bleaching is good, the intensity height, and the finished paper that is ferreted out is better than rotary spherical digester paper pulling force, and can be used to produce various cultural papers.
Three, soak the processing of black liquor and recycling of waste water; the waste water that wheat straw is produced in pulping process has black and not dense; viscosity is little; solid content in the waste water is few; only residual a spot of heteroproteose cell, and soup has been protected carbohydrate, promptly can be recycled through the sedimentation basin post precipitation; experiment is produced in slurrying through hundreds of time in batches, use recirculated water to pulping bleaching without any influence.
Four, water analysis and middle section water are handled: the paper-making pulping water consumption be everybody knows greatly, and the water discharge capacity of producing one ton of paper is not less than 200 tons, and the processing of middle section water is also brought great pressure.The outer discharge capacity of using drug immersion ryegrass pulping method waste water of the present invention is just low many, and cost for wastewater treatment is low, the good and reclamation rate height of water quality.Make about 140 tons of the water consumptions of one ton of paper, the COD average about 1700 of total draining.