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Coal Chemical Refinement Of This Important Technical Way You Understand?
Dec 19, 2017

Modern coal chemical project is a capital, technology, resource-intensive industries, its huge investment, easily tens of billions of yuan, tens of billions of yuan, or even hundreds of billions of dollars, is a very risky industry, once the project suffered production capacity Excess and long-term losses will bring incalculable losses to enterprises, government, society and banks. Modern coal chemical industry is in a critical turning-point, China has a large number of built and are under the coal-to-olefin, methanol-to-olefins downstream products how to develop? Methanol to aromatics downstream products how to develop? Coal-based large-scale production capacity of calcium carbide how to solve? Coal chemical industry how to use a lot of CO2 emissions? Coal oil, coal gas and coal separation and other deep-processing products how to make rational use of? The above common problems of modern coal chemical industry, coal chemical industry has been subject to all levels of government and coal chemical investors are highly concerned about, no doubt the refinement of modern coal chemical industry is the only way for the future development. To this end, this article discusses the development of polyurethane is an important technical approach to the refinement of modern coal chemical industry, and systematically put forward the specific technical approach and market conditions of coal-based PU. This paper points out that coal-based PU is not only the development direction of refinement of modern coal chemical industry, but also an important technical way for China to achieve the goal of leapfrog development of PU in China.

A coal-based olefin PU technology route

Coal-based methanol → olefin → propylene oxide → polyether polyol → PU foam and other product line technology

The coal-to-olefin (CTO, MTO, MTP), pioneered by the Chinese Academy of Sciences and other units, is an original technology for the production of olefins in modern coal chemical industry in China. It plays an important role in the petrochemical industry itself, which is an important raw material for supporting olefins. Among them, MTP (methanol-to-propylene) has a high degree of relevance to the polyurethane industry and plays an important role in promoting the development of polyurethane in China. Coal-based olefin technology is therefore an important measure to achieve the refinement of coal-based PU.

The process routes include:

(1) Methanol → Olefin → Propylene

(2) Propylene → PO (propylene oxide)

(3) PO → PPG (polyether polyol)

(4) PPG → PU soft foam, foam

1.1 propylene → propylene oxide

PO manufacturing methods are chlorohydrin method, co-oxidation method and direct oxidation method (HPPO) chlorohydrin method has been included in the ban because of environmental issues.

(1) co-oxidation (co-production method) is divided into ethylbenzene co-oxidation and isobutane oxidation

The former is co-produced in addition to PO PO styrene, which co-tert-butanol. For each ton of PO produced, 2.25 tons of styrene or 3.08 tons of MTBE (methyl tert-butyl ether) co-produced have exceeded the production of the main PO. MTBE which is processed by TBA (tert-butanol), is a gasoline additive. Domestic Yantai Wanhua PO / TBA production of propylene oxide. Huntsman also owns PO / TBA technology and Shell / Leander has PO / PM (Styrene) technology.

(2) Hydrogen peroxide direct oxidation method (HPPO method)

HPPO method is hydrogen peroxide (hydrogen peroxide) catalyzed epoxidation of propylene PO new technology, the process of producing only PO and water. Foreign master HPPO Act Tao Tao Chemical and BASF Corporation, jointly developed in Thailand has built an annual output of 390,000 tHPPO production line. Evonik Industrial Group and Wood Corporation in Jilin Shenhua has built an annual output of 300,000 tHPPO production line. Sinopec Baling Petrochemical own technology has been built with an annual output of 100,000 tHPPO device. The Institute of Chinese Academy of Sciences also has this technology, and in 2012 by the Chinese Academy of Sciences Shenyang Research Institute and other units passed the pilot test, is an original technology, is currently undergoing 10,000-ton scale test. The HPPO technology holds the hydrogen peroxide consumption below the international level, with low cost advantage. HPPO method compared with other processes, with high yield, high purity, less impurities, etc., to improve the quality of downstream products polyether polyol is particularly important. Compared with the chlorohydrin method, almost no waste generated, low environmental costs.

According to the statistics of China PU Industry Association, in 2014, China's PO production capacity will reach 2.6 million tons and the output will be 2.1 million tons. The operating rate will be 81%. This year, the production capacity will exceed 3 million tons. 2020 capacity will exceed 4 million t, PO average growth rate of 9% in the next few years. In 2014, the global PO total production capacity was 9.94 million tons / year, the output was about 8.85 million tons / year, and the operating rate was about 86%. Production facilities are mainly concentrated in the United States, Western Europe and China, of which the United States accounted for 24%, Western Europe accounted for 28%, China 22%, Japan 6%. The concentration of PO in the world is very high. In 2014, the Dow Chemical PO production capacity in the United States reached 2.28 million tons / year, that of Leandr in the Netherlands 2.2 million tons / year, that of the Dutch Shell 800,000 tons / year and that of BASF in Germany 530,000 tons / Year, Japan and Saudi Arabia 330,000 t / year, the above five major PO production capacity of 60% of the global total capacity.

1.2PO → PPG (polyether polyol)

Propylene oxide 80% for PPG, 10% propylene glycol, the other for the production of propylene glycol ether, isopropanolamine and so on.

Most of the world's PO manufacturers have built a downstream polyether polyol production plant, PO only as an intermediate raw material. For example, Tao Tao Chemical is one of the largest producers of polyether polyols in the world, with an annual output of 1.5 million tons of PPG. 96% of its production is self-digested and only 4% is distributed as commodities. Germany Bayer PPG with an annual output of 1.2 million t, BASF with an annual output of 760,000 t PPG, the Netherlands Shell annual 640,000 t PPG, basically self-digestion, supporting the production of downstream PPG. Domestic Wanhua is also such a model, first produced PPG, and later expanded to the upstream reproduction of PO, the formation of PO → PPG integration.

According to the statistics of China PU Industry Association, the production capacity of polyether polyol in 2014 was over 4 million t / y and the output was 2.8 million t. It is estimated that the polyether polyol production capacity will reach 5 million tons by 2018. China's polyether production capacity is mainly concentrated in East China. In 2014, East China accounted for 70%, of which Shandong accounted for 25%, followed by South China 14%, North China 10% and Northeast Northeast 6%.

1.3 polyether polyol (PPG) → PU foam and other products

PPG is one of the most versatile raw materials for PU products, with PPG requiring a small amount of ethylene oxide (EO) in addition to PO. Manufacture of special polyether polyol POP (graft polyether polyol), also need two raw materials, styrene and acrylonitrile, both raw materials can be obtained from the coal chemical industry.

POP accounted for 20% of polyether polyol. The main consumer PPG used to manufacture PU foam, consumption accounts for about 80%. PPG is also used in the manufacture of elastomers, shoes, paints, adhesives, sealants and other PU products.

According to the statistics of China PU Industry Association, the consumption of PU foam in China was 3.7 million tons in 2014, of which 1.6 million tons were made of soft foam, 2.1 million tons of rigid foam, 2.2 million tons of PU synthetic leather, 820,000 tons of elastomer and 420,000 tons of sole stock , Spandex 460000 t, paint 1.45 million t. Adhesives / sealants 550,000 t, a total of 9.6 million t.

PU soft foam main application areas: software furniture, automobiles, motorcycles, shoes and so on. PU foam main application areas: refrigerators, freezers, refrigerated containers, building wall insulation, pipe insulation, solar hot water pipe insulation.

It can be seen that coal-to-olefin (CTO, MTO, MTP) provides a sufficient source of raw materials for the production of PO and PPG, the key raw materials for PU. PU products are widely used and their added value is higher than that of polypropylene products. Therefore, coal-based olefins → PO → PPG → PU are an important technical approach for coal-based refinement.

2 coal-based acetylene PU technology route

Coal-based calcium carbide → acetylene → BDO (1.4-butanediol) → THF (tetrahydrofuran) → PTMEG (polytetrahydrofuran) → PU fiber (spandex) industrial chain. The technical route includes:

2.1 Coal-based BDO (1.4-butanediol)

Process route: methanol → formaldehyde + acetylene → butynediol (hydrogenation) → BDO. The process that aldol aldehyde (Reppe France said) the process route characteristics:

① rich sources of raw materials: the main raw material for calcium carbide (acetylene). Calcium carbide is one of the main products of coal chemical industry, other raw materials for methanol (formaldehyde) and hydrogen, is the main product of coal chemical industry.

② low production costs: calcium carbide excess capacity, cheap, especially in the western low-cost areas lower cost. Therefore, the manufacturing cost of the BDO produced by the process route is significantly lower than that of the petroleum route (maleic anhydride method, n-butane method, butadiene method and propylene oxide method), which has a greater cost advantage. In addition, calcium carbide production process can also produce BDO, the production cost is lower. According to the statistics of China PU Industry Association, the production capacity of BDO in 2014 will be 1.7 million tons, the production rate will be 1.2 million tons and the production rate will be 71%. The production capacity will exceed 3 million tons in 3-5 years. The new production capacity will mainly dominate the coal chemical industry. BDO main area of consumption THF / PTMEG, about 40%, PU shoes, elastomers and other fields account for about 20%.

2.2 Coal-based PTMEG (polytetrahydrofuran)

Process route: BDO → THF (tetrahydrofuran) → PTMEG (polytetrahydrofuran)

The process features: ① low production costs, consumption of 1.3 tons per ton of PTMEG BDO, coal chemical low-cost BDO decided PTMEG low-cost. ② The technology is mature. Three-dimensional coal chemical companies in Shanxi Province have built a number of PTMEG production plants with an annual output of 10,000 tons of coal chemical industry in recent years.

According to the statistics of "Global PU Network", the production capacity of PTMEG in China reached 554,000 tons and the output reached 307,000 tons in 2014. The new production capacity of PTMEG will reach 434,000 tons in 2017, mainly in the coal producing areas of Xinjiang, Shanxi, Shaanxi and Ningxia in China Our total PTMEG capacity will reach 740,000 t.

2.3 coal-based PTMEG → spandex

70% of PTMEG consumption in China is for producing spandex (PU fiber). China is the largest producer, consumer and exporter of spandex in the world. According to the statistics of China Chemical Fiber Association, in 2014, the production capacity of spandex in China is about 600,000 tons, the output is about 460,000 tons, and the production capacity accounts for 40% of the global total. At present, there are more than 30 spandex producers in China, of which more than 20 have production capacity of more than 10,000 tons. Zhejiang Huafeng, South Korea Hyosung and the United States INVISTA is the major producers of spandex. The Yangtze River Delta with Wenzhou in Zhejiang Province as the center is the most developed region of China's spandex industry, accounting for about 70% of the country's total capacity and output, of which Zhejiang accounts for 50% of the total. Spandex is mainly used in high-grade textile underwear, sportswear, socks, casual wear, swimwear, jeans, jackets and so on, as well as automotive, aircraft seat belts and medical bandages, wound stickers, knee pads and other fields. Spandex PU products is one of the highest added value products, the current market price of 20D spandex 60,000 yuan / t or so. 40D Spandex average price of 50,000 yuan / t or so, the profit margin is high. Since 2013, the operation rate of domestic spandex industry has been maintained at about 90%. There are 4 spandex producers listed in Shanghai and Shenzhen Stock Exchanges, namely Huafon Spandex, Yantai Taihe New Material, Henan Xinxiang Chemical Fiber Co., Ltd. and Woori Holdings. Huafeng Spandex net profit growth in 2013 was 1258.5% ~ 1584.5%, Taihe new material growth of 79.99% to 124.98%, Xinxiang Chemical Fiber net profit growth of 121.69%. China's Xinjiang, Shanxi, Inner Mongolia, Shaanxi is an important modern coal chemical production base, have built BDO and PTMEG production plant, the textile industry also has some basis.

In the western region, spandex is currently empty. Especially in Xinjiang, the development of coal-based spandex has the advantages of low raw material cost and large market radiance. It is the best way to realize the refinement of coal-based calcium carbide (acetylene) spandex. Xinjiang is expected to soon be Wenzhou, Chongqing, China's third spandex industrial base.

3 coal-based carbon dioxide PU technology route

In the development of coal chemical industry encountered a prominent contradiction to generate a large amount of CO2. With an annual output of 200,000 tons of methanol will generate 320,000 tons of CO2, equivalent to 1.6 tons of methanol emissions of 1 ton of CO2 emissions much greater than the petrochemical line. Therefore, the development of coal chemical industry must solve the CO2 utilization technology, among them: CO2 + propylene oxide (or propylene oxide + ethylene oxide or cyclohexane) → PPC (poly propylene carbonate polyol) → PU products PU foam, elastomer, PU leather, paint, water-based PU, adhesive, etc.) PU products synthesized by PPC have low cost, biodegradability and flame retardancy. PPC is a kind of cost-effective material. For the development of B2-level and B1-level flame retardant PU foam, creating favorable conditions. PPC has been made from Japan with biodegradable materials, has been used in areas such as automobiles. Jiangsu Taizhou Jinlong and Huizhou Daya Bay Dazhi company PPC has industrialized production and has been applied to PU multiple products, the German Bayer also developed into such products.

From the CO2 and propylene oxide or propylene oxide and ethylene oxide or cyclohexane synthesis PPC, and then PPC and isocyanate (MDI, TDI, HDI, etc.) can generate a series of PU products. This is a mature process route, which is a green refined development of coal-based PU road, it is worth the domestic coal chemical companies to promote. CO2-based PU and other new polymers is the common focus of the current polymer areas of focus.

4 coal-based carbon ester dimethyl ester (DMC) PU technical route

There are two major uses of DMC for coal-based PUs: one is the synthesis of HDI (hexamethylene diisocyanate) by non-phosgene and the other is the synthesis of high-end polyol polycarbonate polyols (PCDL).

Process route: DMC + BDO (or diol, cyclohexanediol) → PCDL

PCDL is a high performance, high value-added polyol (currently the domestic price of 5-6 yuan / t) is the key raw material for manufacturing high-performance polyurethane elastomer, water-based PU, synthetic leather and melt spinning spandex TPU sections.

Japan's Utsunomiya and Asahi Kasei have built an annual output of 3000t production line in Nantong, Jiangsu Province, has built an annual output of 6000 tons in Spain, Japan has built an annual output of 8000t production line. At present, all domestic PCDLs are imported from Japan and Bayer of Germany. The Shanxi Coal and Metallurgical Institute of CAS, Chengdu Institute of Organic Chemistry have completed the pilot and pilot tests.

DMC synthesis methods are:

(1) phosgene law

(2) transesterification method: CO2 + propylene oxide (or ethylene oxide)

(3) urea alcoholysis method: methanol + urea + propylene glycol

(4) methanol oxidation carbonyl method

2CH3OH + CO + 1 / 2O2 → (DMC) + H2O

The method uses methanol, CO and O2 as raw materials, the raw materials are cheap and easy to obtain, the investment is low and the cost is low. In theory, all the methanol is converted into DMC without any other byproducts. The method is greatly valued by the industry and owned by the Chengdu Institute of Organic Chemistry The technology, has achieved 10,000-ton production plant.

DMC is a multipurpose fine chemical product as well as a gasoline additive that is essential for the development of high-end PU raw material isocyanate HDI and high-end polyester polyol PCDL. Japan Udo in order to produce PCDL own production supporting DMC.

5 coal-based non-phosgene isocyanate manufacturing technology route

There are currently two basic types of isocyanates: one is phosgene, which utilizes the phosgene of diamines (including aliphatic diamines and aromatic diamines) to make diisocyanates using phosgene (COCl2) and the other is non-ionic Phosgene Act. Phosgene is a highly toxic raw material, the country's production of phosgene is strictly limited. Therefore unconditionally built phosgene coal chemical industry, the non-phosgene production of isocyanate raw materials. At present, Shandong Runxing Chemical Technology Company has adopted the non-phosgene law to build an annual output of 20,000 tHDI production line. Sichuan Hongguo Technology