Development trend of cellulose ether market

The production and consumption of hydroxymethyl cellulose and methyl cellulose and their derivatives were introduced, and the future market demand was predicted. The competition factors and problems in the cellulose ether industry were analyzed. Some suggestions on the development of cellulose ether industry in our country were given.

Key words: cellulose ether; Market demand analysis; Market research

1. Classification and use of cellulose ether

1.1 Classification

Cellulose ether is a polymer compound in which the hydrogen atoms on the anhydrous glucose unit of cellulose are replaced by alkyl or substituted alkyl groups. On the chain of cellulose polymerization. Each anhydrous glucose unit has three hydroxyl groups that can participate in the reaction if completely replaced. The value of DS is 3, and the degree of substitution of commercially available products ranges from 0.4 to 2.8. And when it’s replaced by an alkenyl oxide, it can form a new hydroxyl group that can be further replaced by a hydroxyl alkyl group, so it forms a chain. The mass of each anhydrous glucose olefin oxide is defined as the molar substitution number (MS) of the compound. The important properties of commercial cellulose ether mainly depend on the molar mass, chemical structure, substituent distribution, DS and MS of cellulose. These properties usually include solubility, viscosity in solution, surface activity, thermoplastic layer properties and stability against biodegradation, thermal reduction and oxidation. The viscosity in solution varies according to the relative molecular mass.

Cellulose ether has two categories: one is ionic type, such as carboxymethyl cellulose (CMC) and polyanionic cellulose (PAC); The other type is non-ionic, such as methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC) and so on.

1.2 Usage

1.2.1 CMC

CMC is an anionic polyelectrolyte soluble in both hot and cold water. The most widely used product has a DS range of 0.65 ~ 0.85 and a viscosity range of 10 ~ 4 500 mPa. s. It is marketed in three grades: high purity, intermediate and industrial. High purity products are more than 99.5% pure, while intermediate purity is more than 96%. High purity CMC is often called cellulose gum, can be used in food as a stabilizer, thickening agent and moisturizing agent and used in medicine and personal care products as a thickening agent, emulsifier and viscosity control agent, oil production is also used in high purity CMC. Intermediate products are mainly used in textile sizing and papermaking agents, other uses include adhesives, ceramics, latex paints and wet base coatings. Industrial grade CMC contains more than 25% sodium chloride and sodium oxyacetic acid, which was previously mainly used in detergent production and the industry with low purity requirements. Because of its excellent performance and wide range of uses, but also in the continuous development of new application fields, the market prospect is very broad, great potential.

1.2.2 Nonionic cellulose ether

It refers to a class of cellulose ethers and their derivatives which do not contain dissociable groups in their structural units. They have better performance than ionic ether products in thickening, emulsification, film forming, colloid protection, moisture retention, adhesion, anti-sensitivity and so on. Widely used in oilfield exploitation, latex coating, polymer polymerization reaction, building materials, daily chemicals, food, pharmaceutical, paper making, textile printing and dyeing and other industrial sectors.

Methyl cellulose and its main derivatives. Hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose are nonionic. They are both soluble in cold water but not in hot water. When their aqueous solution is heated to 40 ~ 70℃, the gel phenomenon appears. The temperature at which gelation occurs depends on the type of gel, the concentration of the solution, and the degree to which other additions are added. The gel phenomenon is reversible.

(1)HPMC and MC. The use of MCS and HPMCS varies depending on the grade: good grades are used in food and medicine; Standard grade available in paint and paint remover, bond cement. Adhesives and oil extraction. In the non-ionic cellulose ether, MC and HPMC are the largest market demand.

The construction sector is the largest consumer of HPMC/MC, mainly used for nesting, surface coating, tile paste and addition to cement mortar. In particular, in cement mortar mixed with a small amount of HPMC can play a stickiness, water retention, slow coagulation and air bleed effect. Obviously improve the cement mortar, mortar, adhesive properties, freezing resistance and heat resistance and tensile and shear strength. Thus improving the construction performance of building materials. Improve the construction quality and the efficiency of mechanized construction. At present, HPMC is the only cellulose ether products used in building sealing materials.

HPMC can be used as pharmaceutical excipients, such as thickening agent, dispersant, emulsifier and film forming agent. It can be used as film coating and adhesive on tablets, which can significantly improve the solubility of drugs. And can enhance the water resistance of the tablets. It can also be used as suspension agent, eye preparation, slow and controlled release agent skeleton and floating tablet.

In the chemical industry, HPMC is an assistant for the preparation of PVC by suspension method. Used to protect colloid, enhance suspension force, improve the shape of PVC particle size distribution; In the production of coatings, MC is used as thickener, dispersant and stabilizer, such as film forming agent, thickener, emulsifier and stabilizer in latex coatings and water-soluble resin coatings, so that the coating film has good wear resistance, uniform coating and adhesion, and improve the surface tension and pH stability, as well as the compatibility of metal color materials.

(2)EC, HEC and CMHEM. EC is a white, odorless, colorless, non-toxic particulate matter that usually dissolves only in organic solvents. Commercially available products come in two DS ranges, 2.2 to 2.3 and 2.4 to 2.6. The content of ethoxy group affects the thermodynamic properties and thermal stability of EC. EC dissolves in a large number of organic solvents over a wide temperature range and has a low ignition point. EC can be made into resin, adhesive, ink, varnish, film and plastic products. Ethyl hydroxyethyl cellulose (EHEC) has a hydroxymethyl substitution number close to 0.3, and its properties are similar to EC. But it also dissolves in cheap hydrocarbon solvents (odorless kerosene) and is used mainly in surface coatings and inks.

Hydroxyethyl cellulose (HEC) is available in either water – or oil-soluble products with a very wide viscosity range. Its non-ionic water soluble soluble in both hot and cold water, has a wider range of commercial applications, mainly used in latex paint, oil extraction and polymerization emulsion, but it can also be used as adhesives, adhesives, cosmetics and pharmaceutical additives.

Carboxymethyl hydroxyethyl cellulose (CMHEM) is a hydroxyethyl cellulose derivative. Relative to CMC, it is not easy to be deposited by heavy metal salts, mainly used in oil extraction and liquid detergents.

2. World cellulose ether market

At present, the total production capacity of cellulose ether in the world has exceeded 900,000 t/a. The global cellulose ether market exceeded $3.1 billion in 2006. The market capitalization shares of MC, CMC and HEC and their derivatives were 32%, 32% and 16%, respectively. The market value of the MC is the same as that of the CMC.

After years of development, the market of cellulose ether in developed countries has been very mature, and the market of developing countries is still in the growth stage, so it will be the main driving force for the growth of global cellulose ether consumption in the future. The existing CMC capacity in the United States is 24,500 t/a, and the total capacity of other cellulose ether is 74,200 t/a, with a total capacity of 98,700 t/a. In 2006, the production of cellulose ether in the United States was about 90,600 t, the production of CMC was 18,100 t, and the production of other cellulose ether was 72,500 t. Imports were 48,100 tons, exports 37,500 tons, and apparent consumption reached 101,200 tons. Cellulose consumption in Western Europe was 197,000 tons in 2006 and is expected to maintain an annual growth rate of 1% in the next five years. Europe is the largest consumer of cellulose ether in the world, accounting for 39% of the global total, followed by Asia and North America. CMC is the main variety of consumption, accounting for 56% of the total consumption, followed by methyl cellulose ether and hydroxyethyl cellulose ether, accounting for 27% and 12% of the total, respectively. The average annual growth rate of cellulose ether is expected to remain at 4.2% from 2006 to 2011. In Asia, Japan is expected to remain in negative territory, while China is expected to maintain a growth rate of 9%. North America and Europe, which have the highest consumption, will grow by 2.6% and 2.1%, respectively.

3. Current situation and development trend of CMC industry

The CMC market is divided into three levels: primary, intermediate and refined. CMC’s primary products market is controlled by a number of Chinese companies, followed by CP Kelco, Amtex and Akzo Nobel with 15 per cent, 14 per cent and 9 per cent market shares respectively. CP Kelco and Hercules/Aqualon account for 28% and 17% of the refined grade CMC market, respectively. In 2006, 69% of CMC installations were operating globally.

3.1 United States

The current production capacity of CMC in the United States is 24,500 t/a. In 2006, the production capacity of CMC in the United States was 18,100 t. The main producers are Hercules/Aqualon Company and Penn Carbose Company, with the production capacity of 20,000 t/a and 4,500 t/a, respectively. In 2006, U.S. imports were 26,800 tons, exports 4,200 tons, and apparent consumption was 40,700 tons. It is expected to grow at an average annual rate of 1.8 percent over the next five years and consumption is expected to reach 45,000 tons in 2011.

High purity CMC(99.5%) is mainly used in food, pharmaceutical and personal care products, and mixtures of high and medium purity (greater than 96%) are mainly used in the paper industry. Primary products (65% ~ 85%) are mainly used in detergent industry, and the remaining market shares are oilfield, textile and so on.

3.2 Western Europe

In 2006, Western European CMC had a capacity of 188,000 t/a, production of 154,000 t, operating rate of 82%, export volume of 58,000 t and import volume of 4,000 t. In Western Europe, where competition is fierce, many companies are shutting down factories with outdated capacity, especially those producing primary goods, and increasing the operating rate of the rest of their units. After modernization, the main products are refined CMC and high value-added primary CMC products. Western Europe is the world’s largest cellulose ether market and the largest net exporter of CMC and non-ionic cellulose ether. In recent years, the Western European market has entered a plateau, and the growth of cellulose ether consumption is limited.

In 2006, the consumption of CMC in Western Europe was 102,000 tons, with a consumption value of about $275 million. It is expected to maintain an average annual growth rate of 1% in the next five years.

3.3 Japan

In 2005, Shikoku Chemical Company stopped production at the Tokushima plant and now the company imports CMC products from the country. In the past 10 years, the total capacity of CMC in Japan has basically remained unchanged, and the operating rates of different grades of products and production lines are different. The capacity of refined grade products has increased, accounting for 90% of the total capacity of CMC.

As can be seen from the supply and demand of CMC in Japan in recent years, the proportion of refined grade products is increasing year by year, accounting for 89% of the total output in 2006, which is mainly attributed to the market demand for high purity products. At present, the main manufacturers all provide products of various specifications, the export volume of Japanese CMC is increasing gradually, roughly estimated to account for about half of the total output, mainly exported to the United States, Chinese mainland, Taiwan, Thailand and Indonesia. With strong demand from the global oil recovery sector, this export trend will continue to grow over the next five years.

4、non-ionic cellulose ether industry status and development trend

The production of MC and HEC is relatively concentrated, with the three manufacturers occupying 90% of the market share. HEC production is the most concentrated, with Hercules and Dow accounting for more than 65% of the market, and most cellulose ether manufacturers concentrated in one or two series. Hercules/Aqualon manufactures three lines of products as well as HPC and EC. In 2006, the global operating rate of MC and HEC installations was 73% and 89%, respectively.

4.1 United States

Dow Wolff Celluosies and Hercules/Aqualon, the major non-ionic cellulose ether producers in the US, have a combined total production capacity of 78,200 t/a. Production of nonionic cellulose ether in the United States in 2006 was about 72,500 t.

Nonionic cellulose ether consumption in the United States in 2006 was about 60,500 t. Among them, the consumption of MC and its derivatives was 30,500 tons, and the consumption of HEC was 24,900 tons.

4.1.1 MC/HPMC

In the United States, only Dow manufactures MC/HPMC with a production capacity of 28,600 t/a. There are two units, 15,000 t/a and 13,600 t/a respectively. With production of around 20,000 t in 2006, Dow Chemical holds the largest share of the construction market, having merged Dow Wolff Cellulosics in 2007. It has expanded its business in the construction market.

At present, the market of MC/HPMC in the United States has been basically saturated. In recent years, the market growth is relatively slow. In 2003, the consumption is 25,100 t, and in 2006, the consumption is 30,500 t, of which 60% products are used in the construction industry, about 16,500 t.

Industries such as construction and food and medicine are the main drivers of MC/HPMC market development in the US, while demand from the polymer industry will remain unchanged.

4.1.2 HEC and CMHEC

In 2006, the consumption of HEC and its derivative carboxymethyl hydroxyethyl cellulose (CMHEC) in the United States was 24,900 t. Consumption is expected to grow at an average annual rate of 1.8% by 2011.

4.2 Western Europe

Western Europe ranks first in the production capacity of cellulose ether in the world, and is also the region with the most MC/HPMC production and consumption. In 2006, sales of Western European MCS and their derivatives (HEMCs and HPMCS) and HECs and EHECs were $419 million and $166 million, respectively. In 2004, the production capacity of non-ionic cellulose ether in Western Europe was 160,000 t/a. In 2007, the output reached 184,000 t/a, and the output reached 159,000 t. The import volume was 20,000 t and the export volume was 85,000 t. Its MC/HPMC production capacity reaches about 100,000 t/a.

Non-ionic cellulose consumption in Western Europe was 95,000 tons in 2006. The total sales volume reaches 600 million US dollars, and the consumption of MC and its derivatives, HEC, EHEC and HPC are 67,000 t, 26,000 t and 2,000 t, respectively. The corresponding consumption amount is 419 million US dollars, 166 million US dollars and 15 million US dollars, and the average annual growth rate will be maintained at about 2% in the next five years. In 2011, the consumption of non-ionic cellulose ether in Western Europe will reach 105,000 t.

The consumption market of MC/HPMC in Western Europe has entered a plateau, so the consumption growth of cellulose ether in Western Europe is relatively limited in recent years. The consumption of MC and its derivatives in Western Europe was 62,000 t in 2003 and 67,000 t in 2006, accounting for about 34% of the total consumption of cellulose ether. The largest consumption sector is also the construction industry.

4.3 Japan

Shin-yue Chemical is a leading global manufacturer of methyl cellulose and its derivatives. In 2003 it acquired Clariant of Germany; In 2005 it expanded its Naoetsu plant from 20,000 L/a to 23,000 t/a. In 2006, Shin-Yue expanded the cellulose ether capacity of SE Tulose from 26,000 t/aa to 40,000 t/a, and now the total annual capacity of Shin-Yue’s cellulose ether business globally is about 63,000 t/a. In March 2007, Shin-etsu halted production of cellulose derivatives at its Naoetsu plant due to an explosion. Production resumed in May 2007. Shin-etsu plans to buy MC for building materials from Dow and other suppliers when all cellulose derivatives are available at the plant.

In 2006, Japan’s total production of cellulose ether other than CMC was about 19,900 t. The production of MC, HPMC and HEMC accounted for 85% of the total production. The yield of MC and HEC was 1.69 t and 2 100 t, respectively. In 2006, the total consumption of nonionic cellulose ether in Japan was 11,400 t. The output of MC and HEC is 8500t and 2000t respectively.

5、the domestic cellulose ether market

5.1 Production capacity

China is the world’s largest producer and consumer of CMC, with more than 30 manufacturers and an average annual output growth of more than 20%. In 2007, China’s production capacity of CMC was about 180,000 t/a and the output was 65,000 ~ 70,000 t. CMC accounts for nearly 85% of the total, and its products are mainly used in coatings, food processing and crude oil extraction. In recent years, the domestic demand for other cellulose ether products other than CMC is increasing. In particular, the pharmaceutical industry needs high quality HPMC and MC.

The research and development and industrial production of nonionic cellulose ether started in 1965. The main research and development unit is Wuxi Chemical Research and Design Institute. In recent years, the research and development of HPMC in Luzhou Chemical Plant and Hui ‘an Chemical Plant have made rapid progress. According to survey, in the recent years, the demand for HPMC in our country has been growing at 15% per year, and the majority of HPMC’s manufacturing equipment in our country are established in 1980s and 1990s. Luzhou Chemical Plant Tianpu Fine Chemical began to research and develop HPMC again in the early 1980s, and gradually transformed and expanded from small devices. At the beginning of 1999, HPMC and MC devices with a total production capacity of 1400 t/a were formed, and the product quality reached the international level. In 2002, our country MC/HPMC production capacity is about 4500 t/a, the maximum production capacity of a single plant is 1400 t/a, which was built and put into operation in 2001 in Luzhou North Chemical Industry Co., LTD. Hercules Temple Chemical Co., Ltd. has Luzhou North in Luzhou and Suzhou Temple in Zhangjiagang two production bases, the production capacity of methyl cellulose ether reached 18 000 t/a. In 2005, the output of MC/HPMC is about 8 000 t, and the main production enterprise is Shandong Ruitai Chemical Co., LTD. In 2006, the total productive capacity of MC/HPMC in our country was about 61,000 t/a, and the production capacity of HEC was about 12,000 t/a. Most started production in 2006. There are more than 20 manufacturers of MC/HPMC. HEMC. The total production of nonionic cellulose ether in 2006 was about 30-40,000 t. The domestic production of cellulose ether is more dispersed, the existing cellulose ether production enterprises up to 50 or so.

5.2 Consumption

In 2005, the consumption of MC/HPMC in China was nearly 9 000 t, mainly in polymer production and construction industry. The consumption of nonionic cellulose ether in 2006 was about 36,000 t.

5.2.1 Building materials

MC/HPMC is usually added to cement, mortar and mortar in foreign countries to improve construction quality and efficiency. In recent years, with the development of the domestic construction market, especially the increase of high-grade buildings. The increasing demand for high quality building materials has promoted the increase of MC/HPMC consumption. At present, the domestic MC/HPMC is mainly added to the wall tile glue powder, gypsum grade wall scraping putty, gypsum caulking putty and other materials. In 2006, the consumption of MC/HPMC in the construction industry was 10 000 t, accounting for 30% of the total domestic consumption. With the development of the domestic construction market, especially the improvement of the degree of mechanized construction, as well as the improvement of the building quality requirements, the consumption of MC/HPMC in the construction field will continue to increase, and the consumption is expected to reach more than 15 000 t in 2010.

5.2.2 Polyvinyl chloride

PVC production by suspension method is the second largest consumption area of MC/HPMC. When the suspension method is used to produce PVC, the dispersion system directly affects the quality of the polymer product and its finished product. Adding a small amount of HPMC can effectively control the particle size distribution of the dispersion system and improve the thermal stability of the resin. Generally, the addition amount is 0.03%-0.05% of the output of PVC. In 2005, the national output of polyvinyl chloride (PVC) was 6.492 million t, of which suspension method accounted for 88%, and HPMC consumption was about 2 000 t. According to the development trend of domestic PVC production, it is expected that the production of PVC will reach more than 10 million t in 2010. Suspension polymerization process is simple, easy to control, and easy to large-scale production. The product has the characteristics of strong adaptability, which is the leading technology of PVC production in the future, so the amount of HPMC in the field of polymerization will continue to increase, the amount is expected to be about 3 000 t in 2010.

5.2.3 Paints, foodstuffs and pharmaceuticals

Coatings and food/pharmaceutical production are also important consumption areas for MC/HPMC. Domestic consumption is 900 t and 800 t respectively. In addition, daily chemical, adhesives and so on also consume a certain amount of MC/HPMC. In the future, the demand for MC/HPMC in these application fields will continue to increase.

According to the above analysis. In 2010, the total demand of MC/HPMC in China will reach 30 000 t.

5.3 Import and Export

In recent years, with the rapid development of our economy and cellulose ether production, cellulose ether import and export trade industry has been growing rapidly, and the export speed far exceeds the import speed.

Due to the high quality HPMC and MC needed by the pharmaceutical industry can not meet the market demand, so with the market demand for high quality cellulose ether growth, the average annual growth rate of the import of cellulose ether reached nearly 36% from 2000 to 2007. Before 2003, our country basically did not export cellulose ether products. Since 2004, the export of cellulose ether exceeded l000 t for the first time. From 2004 to 2007, the average annual growth rate was 10%. In 2007, the export volume has exceeded the import volume, among which the export products are mainly ionic cellulose ether.

6. Industry competition analysis and development suggestions

6.1 Analysis of industry competition factors

6.1.1 Raw Materials

Cellulose ether production of the first major raw material is wood pulp, its price trend cycle price rise, reflect the industry cycle and the demand for wood pulp. The second largest source of cellulose is lint. Its source has little effect on the industry cycle. It is mainly determined by the cotton harvest. The production of cellulose ether consumes less wood pulp than other chemical products, such as acetate fiber and viscose fiber. For manufacturers, raw material prices are the biggest threat to growth.

6.1.2 Requirements

The consumption of cellulose ether in bulk consumption areas such as detergent, coatings, building products and oilfield treatment agents accounts for less than 50% of the total cellulose ether market. The rest of the consumer sector is fragmented. Cellulose ether consumption accounts for a small proportion of raw material consumption in these areas. Therefore, these terminal enterprises have no intention to produce cellulose ether but to buy from the market. The market threat is mainly from alternative materials with similar functions as cellulose ether.

6.1.3 Production

The entry barrier of industrial grade CMC is lower than that of HEC and MC, but refined CMC has higher entry barrier and more complex production technology. Technical barriers to entry into the production of HECs and MCS are higher, resulting in fewer suppliers of these products. The production techniques of HECs and MCS are highly secret. Process control requirements are very complex. Producers can produce multiple and different grades of HEC and MC products.

6.1.4 New competitors

Production produces a lot of by-products and the environmental cost is high. a new 10,000 t/a plant would cost $90 million to $130 million. In the United States, Western Europe and Japan. Cellulose ether business is usually less economical than reinvestment. In existing markets. New factories are not competitive. However in our country investment is relatively low and our domestic market has a good prospect for development. With the advancement of technology. Investment in equipment construction is increasing. Thus constitute a higher economic barrier to new entrants. Even existing manufacturers need to expand production if conditions permit.

Investment in R&D for HECs and MCS must be maintained in order to develop new derivatives and new applications. Because of the ethylene and propylene oxides. Its production industry has a greater risk. And the production technology of industrial CMC is available. And relatively simple investment threshold is lower. The production of refined grade requires large investment and complex technology.

6.1.5 Current competition pattern in our country

The phenomenon of disordered competition also exists in the cellulose ether industry. Compared with other chemical projects. Cellulose ether is a small investment. The construction period is short. Widely used. The current market situation is encouraging, because the disorderly expansion of the industry phenomenon is more serious. Industry profits are falling. Although the current CMC operating rate is acceptable. But as new capacity continues to be released. The market competition will become increasingly fierce.

In recent years. Because of domestic overcapacity. CMC output 13 has maintained a rapid growth. But this year, the export tax rebate rate cut, the appreciation of the RMB have made the product export profit decline. Therefore, strengthen technical transformation. Improving product quality and exporting high-end products is the top priority of the industry. Our country cellulose ether industry is compared with abroad. It’s not a small business, though. But the lack of industry development, market change plays a decisive role in leading enterprises. To some extent, it has hindered the industry’s investment in technology upgrading.

6.2 Suggestions

(1) Increase independent research and innovation efforts to develop new varieties. Ionic cellulose ether is represented by CMC(sodium carboxymethyl cellulose). Has a long history of development. Under the continuous stimulation of market demand. Nonionic cellulose ether products have emerged in recent years. Showing strong growth momentum. The quality of cellulose ether products is mainly determined by purity. Internationally. The United States Food and Drug Administration and other clear requirements of CMC products purity should be above 99.5%. At present, output of our country CMC has accounted for 1/3 of world output. But the product quality is low, 1: 1 is mostly low-end products, low added value. CMC exports much more than imports each year. But the total value is the same. Nonionic cellulose ethers also have very low productivity. Therefore, it is important to increase the production and development of nonionic cellulose ether. Now. Foreign enterprises are coming to our country to merge enterprises and build factories. Our country should seize the opportunity of development to promote production level and product quality. In recent years. The domestic demand for other cellulose ether products other than CMC is increasing. In particular, the pharmaceutical industry needs high quality HPMC and MC still need a certain amount of imports. Development and production should be organized.

(2) Improve the technological level of equipment. The mechanical equipment level of domestic purification process is low. Seriously restrict the development of the industry. The main impurity in the product is sodium chloride. Before. Tripod centrifuge is widely used in our country. Purification process is intermittent operation, high labor intensity, high energy consumption. Product quality is also difficult to improve. The national cellulose ether industry Association began to tackle the problem in 2003. Encouraging results have now been achieved. The purity of some enterprise products has reached more than 99.5%. In addition. There is a gap between the automation degree of the whole production line and that of foreign countries. It is suggested to consider the combination of foreign equipment and domestic equipment. Key link supporting import equipment. To improve the automation of the production line. Compared with ionic products, non-ionic cellulose ether requires higher technical level. It is urgent to break through the technical barriers of production process and application.

(3) Pay attention to environmental and resource issues. This year is the year of our energy saving and emission reduction. It is very important for the development of the industry to treat the environmental resource problem correctly. The sewage discharged from cellulose ether industry is mainly solvent distilled water, which has high salt content and high COD. Biochemical methods are preferred.

In our country. The main raw material for the production of cellulose ether is cotton wool. Cotton wool was agricultural waste before the 1980s, using it to produce cellulose ether is to turn waste into treasure industry. However. With the rapid development of viscose fiber and other industries. Raw cotton short velvet has long become the treasure of treasure. Demand is set to outstrip supply. Companies should be encouraged to import wood pulp from foreign countries such as Russia, Brazil and Canada. In order to alleviate the crisis of increasing shortage of raw materials, cotton wool is partially replaced.