Processing and application of tea seed shell

Camellia oleifera is a unique woody oil in China. According to statistics, Camellia oleifera has an area of more than 3.47 million hectares and an annual output of 56.6 billion kg. In the tea seed shell, it contains 52.15% lignin, 30.27% pentose, 5.43% diosgenin, 2.47% tannin, 0.43% water, 0.13% oil and 9.12% other ingredients. Due to the high content of lignin and pentoses in tea seed shell, the research on the utilization of tea seed shell is still focused on the preparation of furfural, activated carbon and xylitol.

1. Preparation of Furfural from Tea seed Shell

(1) the properties and uses of furfural furfural is a widely used chemical substance, which is a light yellow to amber transparent liquid. The color deepens gradually during storage until it turns brown and has the smell of bitter almonds. Furfural is an organic chemical raw material, mainly used in lubricating oil refining and furfuryl alcohol production, but also can produce medicine and veterinary drugs, as well as preservatives, disinfectants, pesticides and detergents and other products, such as food spices, dyes and so on.

(2) the preparation of furfural is a widely used chemical. The theoretical yield of furfural extracted from tea seed shell is 47%, while the actual yield is 19%, which is the highest of all crops. The production process is as follows: acid hydrolysis → neutralization → evaporation → crude distillation → neutralization → refining → finished product.

(3) ① furfuryl alcohol is used as downstream derivative of furfural. Furfuryl alcohol is the most important product in furfural hydrogenation products, which is mainly used to prepare furan resin. it can be used as an adhesive in automobile, tractor and other internal combustion engine casting industry to improve casting quality and promote the level of mechanization and automation of casting process. In addition, it can also be used as a solvent for varnishes, pigments and rocket fuel, as well as an intermediate levulinic acid for the synthesis of calcium fructate, a nutritional drug. ② fumaric acid and its dimethyl ester. Fumaric acid was prepared by oxidation of furfural by potassium chlorate and then esterified with methanol to obtain dimethyl fumarate. Fumaric acid is mainly used in the production of unsaturated polyester resin with good chemical corrosion resistance and heat resistance. Dimethyl fumarate is a new type of antiseptic and mildew preservative for food and feed developed in 1980s with high efficiency, low toxicity and wide application range of pH. Its effect is better than that of benzoic acid, sorbic acid, dehydroacetic acid, propionic acid and its salt preservatives. It can be widely used in food, feed, cosmetic crystal, fruits, vegetables and other products. ③ furoic acid. Furoic acid can be prepared from furfural by air oxidation and is mainly used in the synthesis of tetrahydrofuran, furoamide and furoic acid esters and their salts. It is used as a plasticizer in the plastic industry and as a preservative in the food industry. in addition, it can also be used as a paint additive and an intermediate in medicine and spices. ④ furan. Furan can be prepared by decarbonylation of furfural and is mainly used in organic synthesis. it is the main raw material for the production of furan propylamine, furacilin, furapamidine and dysenter. it can also be used to prepare thiophene, pyrrole, tetrahydrothiophene, tetrahydrofuran, tetrahydropyrrole and other chemical products with good market prospects. ⑤ tetrahydrofurfuryl alcohol. Tetrahydrofurfuryl alcohol, also known as tetrahydrofuran methanol, is prepared by gas phase hydrogenation of furfural in the presence of nickel, chromium and copper catalysts. It is an important chemical raw material and can be used for the synthesis of succinic acid, glutaric acid, dihydrofuran, lysine, pyran and pyridine. Tetrahydrofurfuryl alcohol oil has five colors and good stability to light and heat. It is an excellent plasticizer for polyvinyl chloride. It has high boiling point and is difficult to volatilize. It can be used as a solvent for resins, coatings and oils, as well as a decolorizing and deodorizing agent for fatty acids and some medicines. ⑥ 2-methylfuran. 2-methylfuran was prepared by high temperature and pressure of furfural under the action of Cu-Cr-A1 catalyst. It is an important organic synthesis intermediate, which can be used to prepare pentanediol, acetylpropanol, pentadiene, ketones and methyl tetrahydrofuran. It is also an indispensable raw material for the production of vitamin B1, chloroquine phosphate and primary aminoquine phosphate. In addition, 2-methylfuran is also an important matrix for the synthesis of edible spices 2-methyl-5-acylfuran, 2-methyl-3-furan mercaptan and 2-methyl-5-alkylthiofuran.

two。 Preparation of activated carbon from Tea seed Shell

(1) the properties of activated carbon the surface of activated carbon has many micropores, the surface area of activated carbon with good performance can reach 25 million square meters per 1kg, and the general one also has 10 million square meters. The activated carbon produced by using tea seed shell and its residue from furfural production as raw materials has good comprehensive properties, various quality indexes can reach the level of other fruit shell activated carbon, and the activity yield is high. Raw material consumption and production cost are also close to or better than other lignin raw materials. Its appearance is black and bright, the texture is hard, irregular particles, put under the microscope will see that there are many micropores. This kind of activated carbon can absorb tiny particles and bacteria in water, and can play the role of sterilization, removal of toxins, decolorization and softening water quality, so it is a good chemical filter material.

(2) preparation of activated carbon → carbonization of tea seed shell → water-cooled → boiling → filtration → adjusting pH value → activation → cooling → crushing → product.

(3) Application of activated carbon activated carbon is mainly used in air purification, exhaust adsorption of sewage treatment plant, beverage water treatment, power plant water pretreatment, wastewater recovery pre-treatment, biological sewage treatment, toxic wastewater treatment, petrochemical non-alkali mercaptan removal, solvent recovery, chemical catalyst carrier, filter canister, gold extraction, chemical storage and exhaust purification, food decolorization, automobile exhaust purification, PTA oxidation device to purify gas, etc.

(4) Regeneration of activated carbon products at present, activated carbon has been widely used in environmental protection, industry and civil use, and has achieved considerable results. however, after the adsorption saturation of activated carbon has been replaced, the users discarded, buried or burned it, resulting in a waste of resources and re-pollution to the environment. Activated carbon adsorption is a physical process, so the impurities in the used activated carbon can be desorbed by high temperature steam and restore its original activity, so as to achieve the purpose of reuse and has obvious economic benefits. The regenerated activated carbon can still be reused and recycled continuously.

3. Preparation of xylitol from tea seed shell

(1) the properties of xylitol xylitol, also known as pentanol. Its taste is sweet, its appearance is white crystal powder, and its sweetness is equivalent to sucrose. Its solubility, solution density and refractive index are basically the same as sucrose, so it is an ideal substitute for sucrose. Xylitol is a kind of natural pentositol, which is a universal intermediate of carbohydrate metabolism between human and animals. Xylitol exists widely in all kinds of fruits and vegetables, but its content is very small.

(2) fermentation xylitol tea seed shell → crushing → pretreatment → hydrolysis (acid catalyst) → hydrolysis → purification of → xylose solution → detoxification → fermentation → refined → product.

(3) the function of xylitol as a sweetener, the annual increase of market consumption of xylitol is closely related to its own characteristics. ① prevents dental caries. According to the national oral health epidemic medicine sampling survey, half of the people in our country suffer from dental caries. Dental caries has become one of the most common oral diseases. The cause of dental caries is that people often eat sucrose or foods with high sugar content, and the residual sucrose in the mouth produces acidic substances under the action of bacteria, resulting in the loss of minerals, corrosion of teeth and the formation of dental caries. Regular consumption of xylitol can effectively prevent dental caries, mainly because xylitol will not be fermented and used by bacteria in the mouth. ② lowers blood sugar. Xylitol can be absorbed through the cell membrane without the help of insulin and does not increase blood sugar and urine sugar. Within 12 hours after eating xylitol, 50% to 60% of xylitol is oxidized to carbon dioxide and water, which releases heat and is used by people; 2% to 10% of xylitol is excreted from urine and feces; and 20% to 30% of xylitol is stored in the body as hepatoglycogen or other intermediates without increasing blood sugar value. Other health functions of ③ xylitol. Xylitol can regulate human fat metabolism and reduce the content of free fatty acids in blood, thus reducing the formation of adipose tissue. Its low fever will not increase the activity of human lipase, but can reduce the accumulation of fat in the body. Xylitol can also promote the synthesis of liver glycogen, reduce transaminase, improve the amino acid utilization of glucose, and protect and repair the liver. Xylitol can also eliminate the formation of harmful ketones in the blood and can be used as an antiketone drug. Xylitol can promote the proliferation of beneficial flora in the intestine and regulate the function of intestines and stomach. As a new type of factor to improve gastrointestinal function, xylitol has high functional activity and is a promising functional additive factor. Because of its excellent properties, xylitol can be widely used in food, alcohol, beverages and other products. Xylitol was officially listed as Class A food additive by the International Conference on Food Additives in 1973.

To sum up, the whole body of tea seed shell is a treasure, regardless of its economic value, or its utilization prospect is very attractive, but Camellia oleifera seed processing in China generally does not shell treatment, but directly with the shell to make oil. because the shell contains more pigment and a small amount of wax, these components are dissolved in tea seed oil during oil production, which not only affects the quality of tea seed oil and tea seed meal, but also causes a great waste of resources. The fundamental reason for this phenomenon is that the available value of tea seed shell has not been paid attention to. In fact, as long as a shelling process is added before the oil camellia seed pressing, the tea seed shell can be obtained, so the raw material is easy to obtain, the processing technology is simple, the investment is low, and the effect is quick, which is a typical short, flat and fast project, especially suitable for the production of small and medium-sized enterprises in Camellia oleifera producing areas. it is a shortcut for tea farmers in mountainous areas to shake off poverty and become rich as soon as possible. Therefore, as long as we fully understand the utilization value of tea seed shell and attach importance to the scientific research on the development and utilization of tea seed shell, we can play a positive role in increasing enterprise efficiency and farmers' income.