Lignin removal in the process of papermaking, why should lignin be removed in papermaking, and the i

1. The lignin in the papermaking raw material is soluble in strong acids and alkalis, and the lignin can be removed as long as it is in this environment. Do you refer to pulping or fiber analysis? If it is pulping, it is possible as long as it is under the above conditions.

Nowadays, SODA-AQ and KRAFT pulping methods are commonly used. It is available in the book "Principles and Engineering of Pulping". If you are doing fiber analysis, you can refer to "Pulp and Paper Analysis and Testing".

2. At the end of pulping, the hardness of the pulp can be detected to reflect the condition of the lignin. The removal rate of lignin made by general chemical methods can reach 80 90

3. Because the pulping process is an acidic or alkaline environment, the cellulose and hemicellulose in the raw materials will be degraded, and the end point of cooking should be strictly controlled in the pulping process to prevent overcooking, reduce the yield and pulp strength.

At present, people have not obtained "log lignin", so the study of lignin is actually the study of denatured lignin, lignin as an organic substance second only to cellulose in plant raw materials, is the main component of the plant skeleton formed together with cellulose and hemicellulose, so lignin is a by-product of cellulose application industry. A large number of by-products of modified lignin in the paper industry and wood hydrolysis industry are mainly divided into: (1) lignosulfonate; (2) sulfate lignin; (3) alkali lignin; (4) Four categories of hydrolyzed lignin.

The lignin contained in the black liquor of reed pulp accounts for 1% of the total amount of waste liquid

30 of the total solids

The lignin content of temperate hardwood is 24%-33% for softwood. The lignin content in the black liquor of pine pulp is 25%-35%.

As for the miscellaneous wood and straw grass, it can not be found below, I personally think that the lignin content of the first two is about the same, and the lignin content of the latter two is about the same, if there is a mistake, please advise!

Strength and hardness are not the same thing, lignin will make the paper brittle, so that the strength is weakened, on the contrary, you remove lignin can be conducive to the addition of additives in the later stage and effective action, if there is lignin, lignin will wrap the fiber, so that the fibers can not interweave with each other to form hydrogen bonds, and the final impact is the strength.

Wood affects the strength of the paper.

Nucleolus. The hard outer shell is woody, and it is spine.

The first time I heard about it, I didn't know and talked nonsense, which is a great sadness.

Lignin is a thermoplastic substance, and paper is made of plant fibers.

The cellulose and some hemicellulose in the raw material, lignin plays the role of a binder in the fiber raw material, if not removed, the fiber raw material will not be dispersed into a single fiber, and the combination of paper is achieved by hydrogen bonding between the fibers. Of course, there is also the theory of high-yield pulp, which is to pulp the fiber raw material on the premise of removing less lignin. Having said this, I believe that LZ knows what is the difference between high-yield pulp and ordinary chemical pulp in terms of strength.

Cellulose is used in papermaking. What is Lignin? Qing belt is that we eat peach and plum Yu Jinlu, their kernel outside the hard shell, this kind of thing affects the paper copying, drying, transportation, printing, of course, to remove.

Lignin is a substance to be removed as much as possible in papermaking, and the most important work in the pulping and bleaching stage of papermaking is to remove lignin. Lignin is a substance that connects fibers in plant fiber materials, and the presence of lignin is not conducive to fiber dispersion and the cleaning of the chemical system of the paper machine. Lignin in paper tends to make paper yellow.

Cellulose is used to increase connectivity and toughness, and lignin is originally a by-product of papermaking.

Wood chemical analysis method: a general term for the analysis of various chemical components of wood. It generally includes an overview of the total analysis of timber, experimental methods and techniques; Sample collection and preparation and determination of moisture, synthetic cellulose, -cellulose, nitric-ethanol cellulose, pentosan, lignin sulfate, total sugars (including neutral sugars and uronic acids), methoxy, acetyl group, 1% sodium hydroxide extract, ether extract, phenyl-alcohol extract and cold (hot) water extract, and ash.

In addition to the general weight and volume analysis, with the development of analytical technology and chemical analysis methods, chromatography and spectroscopic analysis with rapid, sensitive, direct determination and small sample size have been widely used, in addition to more accurate determination of each component and functional group content, but also have a deeper understanding of the structure of cellulose, hemicellulose, lignin and extracts and their reaction mechanisms in chemical processing.

What dryer is used? The time and temperature of different drying equipment are different.

The time it takes is about 10-30 seconds for the inlet air temperature to be 350-500 degrees.

Lignin, also known as lignin, is a type of organic matter composed of healous lignophenol propane, lilac propane, p-hydroxyphenylpropane through ether bonds, carbon-carbon bonds, etc., while plant cellulose includes cellulose and hemicellulose, which is glucose monomer and hemicellulose is a polysaccharide. I studied papermaking.

Plant fiber includes cellulose, hemicellulose, lignin, plant cellulose is the main component needed for papermaking, and the more lignin is removed, the better, and the amount of hemicellulose is different according to different paper species.