Internationally speaking, it is not wrong to say that LPG is clean energy, but the premise is that it must meet two conditions. First, the purity of LPG must reach the energy standard for automobiles, and the second is that the engine must meet the requirements. Only in this case can the use of LPG (liquefied petroleum gas) be truly clean energy. ——— Professor Hua Wei, Director of the Huagong Natural Gas Research Center, member of the Chinese People's Political Consultative Conference, and chief scientist of the National Fundamental Research Institute for Energy Efficiency At present, there is no single fuel engine developed specifically for LPG in China. Almost all LPG engines are produced by the process improvement of gasoline engines or diesel engines. The LPG (liquefied petroleum gas) engines used by Guangzhou Public Transport are mainly produced and customized by domestic engine companies such as Yuchai, Weichai, and Cummins. The technical deficiency of LPG (liquefied petroleum gas) engines changed from diesel engines to diesel engines, which leads to problems such as insufficient combustion and increased production of nitrogen oxides. ———Department of Vehicle Engineering, Department of Engineering, South China Agricultural University Professor Liu Zhongguo, Automotive Engine Expert In response to doubts about the environmental protection of LPG (liquefied petroleum gas) buses in Guangzhou, the People’s Congress’s representative recently confirmed that the 172 LPG (liquefied petroleum gas) buses in Shanghai were used for exhaust pollution inspection. There were 150 vehicles that met the standards. 22 vehicles that exceeded the standards were retested after being repaired. There were 21 vehicles that met the standards. The total compliance rate of the rechecks was 99.4%. According to Huang Zuzhao, deputy director and senior engineer of the Guangzhou Environmental Monitoring Center, the center randomly sampled 172 LPG (liquefied petroleum gas) buses from FAW, Second Automobile, Sanqi, and the tram companies. At present, the overall emission of LPG (liquefied petroleum gas) buses is in good condition in our city, said Huang Zuzhao. Huang Zuzhao also revealed that at present, Guangzhou is referring to advanced international and domestic practices, and hastened to study and formulate a regular inspection and compulsory maintenance system for motor vehicle exhaust pollution (referred to as the I/M system for short). This quarter will adopt mandatory measures to supervise enterprises and do a good job. The maintenance of various types of vehicles including LPG (liquefied petroleum gas) vehicles ensures that the vehicle's exhaust emissions meet the standards. At present, the system is soliciting opinions from all walks of life and strives to issue an announcement before the end of the year. Two questions Why the first inspection rate is less than 90% Although only one of the 172 vehicles sampled last failed to meet the standard, the initial inspection compliance rate was only 87.2%. Huang Zuzhao explained that there are many reasons for this, such as the lack of maintenance and repair of the vehicle emission control system, the post-processing device of the vehicle configuration being damaged, deteriorated, or being replaced in time beyond the service period. Excessive gas conditions. He said that after the first inspection of vehicles with exhaust gas exceeding the standard, after undergoing maintenance and repair, emissions will be greatly improved, so the retest rate will generally be higher. This also shows that the maintenance of motor vehicles is very important for pollution control. The result of the sampling inspection of the motor vehicle exhaust pollution in Guangzhou from January to September this year showed that the first inspection compliance rate was 85.6%. Why do you not invite NPC deputies to supervise the scene? Since the deputies of the National People's Congress questioned them, why didn't they go to the scene to supervise them? Huang Zuzhao said that the spot inspection was carried out according to normal procedures and the vehicles were inspected strictly in accordance with the relevant national emission standards and testing technical specifications. So far, no request has been received from the NPC deputies or other parties to put on-site inspections. If delegates put forward requirements in this regard, they can invite deputies to the NPC (including representatives of all sectors of the community) to participate in the supervision in the future. Expert interpretation The problem lies in the inherent deficiency of engine technology Guangzhou LPG (liquefied petroleum gas) bus engine is basically transformed from diesel engine Professor Liu Zhongguo, former head of the Department of Vehicle Engineering at the School of Engineering, South China Agricultural University, introduced that at present, there is no single fuel engine developed specifically for LPG in China. Almost all LPG (liquefied petroleum gas) engines are manufacturers of gasoline engines. Or the diesel engine is produced by process improvement. The specific LPG (liquefied petroleum gas) engines used in Guangzhou buses are mainly produced by custom-made domestic engines such as Yuchai, Weichai, and Cummins. The technical deficiency of the LPG (liquefied petroleum gas) engine changed from diesel engine to diesel engine resulted in problems such as insufficient combustion and increased production of nitrogen oxides during operation, and the lack of performance of the engine in terms of dynamic performance and economic performance. Liu Zhongguo said that there are currently three kinds of air intake methods for diesel LPG engines modified by diesel engines: one is closed-loop electronically controlled air-fuel mixture control (ie, LPG (liquefied petroleum gas) is mixed with air in the air intake), and electronically controlled single-point injection And electronically controlled multi-point injection. Among them, electronically controlled single-jet engines are widely used in Guangzhou, such as Yuchai YC 6 1 2 ZLQ E and Weichai WT 615.00LPG (liquefied petroleum gas). These engines have at least two shortcomings: First, control In some cases, the intake air volume is not easy to control, resulting in incomplete combustion of LPG (liquefied petroleum gas) in the cylinder, which increases the hydrocarbon content in the exhaust gas. Second, the cylinder temperature is too high. Because the diesel engine is transformed, the cylinder is burned by the LPG. Temperatures tend to be high, causing oxygen and nitrogen to react more easily to produce more nitrogen oxides at high temperatures. At the same time, engine parts are more easily lost and lubrication performance is reduced. Chinese laboratories are far from entering the phase-out period The engine mileage is 1268 kilometers, and the engine is only a few days old After the exclusive disclosure of the laborers' test report by the newspaper, on the 22nd, the Guangzhou Environmental Protection Bureau issued a draft that the results of the inspections based on the research report of the National People's Congress represent no practical significance for evaluating the environmental performance of Guangzhou LPG buses. The sampled car was a model that was eliminated in Guangzhou. Yesterday, this newspaper received the "Test Report" of the "Study Report on the Experimental Analysis of HEV, LPG (Liquefied Petroleum Gas) and Diesel Buses" from China Labor. According to the “Sample Vehicle Description†on page 3 of “Inspection Reportâ€, it states that the diesel vehicle submitted for inspection was transformed from Yuchai State III LPG (liquefied petroleum gas) engine based on the urban passenger car produced by Zhengzhou Yutong Bus Co., Ltd. ( The LPG (liquefied petroleum gas) bus is a 1268-kilometer-long engine. The reporter learned from the bus company that the daily mileage of a bus in Guangzhou is about 200 kilometers. Is 1268 km out of the model? Prof. Liu Zhongguo said: With a daily distance of about 200 kilometers, the engine can be installed for only a few days. "This is obviously not a knock-out car." Hong Kong has been engaged in Guangzhou for more than 30 years Prof. Hua Wei said that it is mainly controlled by LPG (liquefied petroleum gas) purity and engine technology reasons. The successful use of taxis in Hong Kong for more than 30 years has made it difficult for Guangzhou's emissions to achieve compliance. Professor Hua Wei, director of the Huagong Natural Gas Research Center, a member of the Provincial Committee of the Chinese People's Political Consultative Conference (CPPCC), and chief scientist of the National Fundamental Research Institute for Energy Efficient Energy, said that he is subject to LPG purity and engine technical reasons. As early as 2004, Hua Wei proposed that it has several advantages over LPG (liquefied petroleum gas) fuel natural gas (LN G): resource potential is far greater than oil; price is cheaper; tail gas pollution is less, fuel is saved, and noise is lower . When Lin Shusen was appointed as secretary of the municipal party committee, he explicitly stated that “the environmental issue of LPG (liquefied petroleum gas) has not been resolvedâ€. Internationally speaking, it is not wrong to speak only about LPG (liquefied petroleum gas) as a clean energy source, but only if it satisfies two conditions. First, the purity of LPG (liquefied petroleum gas) must reach the energy standard for automobiles, and the second is that the engine must meet the requirements. Only in this case can the use of LPG (liquefied petroleum gas) be truly clean energy. Hong Kong's minibuses have used LPG for more than 30 years. Their LPGs are imported from abroad. Only one of them contains only one part per thousand, but the current domestic LPG (liquefied petroleum gas) contains that ingredient. Ten ten thousandths. The engines of Hong Kong are all of Japan's original, and they were specially made to Toyota. Therefore, LPG has been more successful in Hong Kong taxis. However, at present, LPG engines used in the country are all modified from diesel engines. Some of them are well-tuned, others are not well-changed, and are mixed. Polyvinyl chloride (PVC) is a polymer polymerized by vinyl chloride monomer (VCM) in peroxide, azo compound and other initiators or according to the free radical polymerization mechanism under the action of light and heat. Vinyl chloride homopolymer and vinyl chloride copolymer are collectively referred to as vinyl chloride resin.
PVC was once the world's largest general-purpose plastic, which was widely used. It is widely used in building materials, industrial products, daily necessities, floor leather, floor tiles, artificial leather, pipes, wires and cables, packaging film, bottles, foaming materials, sealing materials, fibers and so on.
According to the different application scope, PVC can be divided into: General PVC resin, high degree of polymerization PVC resin and cross-linked PVC resin. Universal PVC resin is formed by polymerization of vinyl chloride monomer under the action of initiator; High degree of polymerization PVC resin refers to the resin polymerized by adding chain growth agent in vinyl chloride monomer polymerization system; Crosslinked PVC resin is a resin polymerized by adding crosslinking agent containing diene and polyene into vinyl chloride monomer polymerization system.
Main purpose: Pvc Resin,Pvc Resin Sg3,Pvc Resin Sg5,Pvc Resin Sg8 Henan Chuange Industry CO.,LTD , https://www.chuangegroup.com
View related topics: New energy vehicles: The magic weapon to deal with energy crisis
PVC is a white powder with amorphous structure, with small branching degree, glass transition temperature of 77 ~ 90 ℃, and it begins to decompose at about 170 ℃ [1]. It has poor stability to light and heat. When it is above 100 ℃ or exposed to sunlight for a long time, it will decompose to produce hydrogen chloride, and further Autocatalytic Decomposition will cause discoloration, and its physical and mechanical properties will also decline rapidly, In practical application, stabilizer must be added to improve the stability to heat and light.
The molecular weight of industrial PVC is generally in the range of 50000 ~ 110000, with great polydispersity. The molecular weight increases with the decrease of polymerization temperature. There is no fixed melting point. It begins to soften at 80 ~ 85 ℃, changes to viscoelastic state at 130 ℃, and changes to viscous flow state at 160 ~ 180 ℃; It has good mechanical properties, with tensile strength of about 60MPa and impact strength of 5 ~ 10kj / m2; It has excellent dielectric properties.
According to the method of obtaining vinyl chloride monomer, it can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (traditionally, ethylene method and imported monomer method are collectively referred to as ethylene method).
1. PVC profile
Profile and profile are the areas with the largest consumption of PVC in China, accounting for about 25% of the total consumption of PVC. They are mainly used to make doors and windows and energy-saving materials. Their application is still growing by a large margin throughout the country. In developed countries, the market share of plastic doors and windows is also the highest, such as 50% in Germany, 56% in France and 45% in the United States.
2. PVC pipe
Among many PVC products, PVC pipe is the second largest consumption field, accounting for about 20% of its consumption. In China, PVC pipe is developed earlier than PE pipe and PP pipe, with many varieties, excellent performance and wide application range, which occupies an important position in the market.
3. PVC membrane
The consumption of PVC in the field of PVC membrane ranks third, accounting for about 10%. After PVC is mixed and plasticized with additives, a transparent or colored film with a specified thickness is made by a three roll or four roll calender. The film is processed by this method to become a calendered film. You can also cut and heat seal packaging bags, raincoats, tablecloths, curtains, inflatable toys, etc. The wide transparent film can be used for greenhouse, plastic greenhouse and plastic film. The biaxially stretched film has the characteristics of thermal shrinkage and can be used for shrinkage packaging.
4. PVC hard materials and plates
PVC is added with stabilizer, lubricant and filler. After mixing, hard pipes, special-shaped pipes and corrugated pipes of various diameters can be extruded by extruder for downcomer, drinking water pipe, wire sleeve or stair handrail. The calendered sheets can be overlapped and hot pressed to make hard plates of various thicknesses. The plate can be cut into the required shape, and then welded into various chemical corrosion-resistant storage tanks, air ducts and containers with PVC electrode and hot air.
5. PVC general soft products
It can be extruded into hoses, cables, wires, etc. by extruder; Plastic sandals, soles, slippers, toys, auto parts, etc. can be made by injection molding machine with various molds.
6. PVC packaging materials
PVC products are mainly used for packaging various containers, films and hard pieces. PVC containers mainly produce mineral water, beverage and cosmetic bottles, and are also used for the packaging of refined oil. PVC film can be used for CO extrusion with other polymers to produce low-cost laminated products and transparent products with good barrier. PVC film can also be used for stretch or heat shrinkable packaging, and for packaging mattresses, cloth, toys and industrial commodities.
7. Pvc wall panels and floors
Pvc wall panels are mainly used to replace aluminum wall panels. In addition to a part of PVC resin, the other components of PVC floor tiles are recycled materials, adhesives, fillers and other components, which are mainly used in the ground of airport terminal building and hard ground in other places.
8. PVC consumer goods
Luggage bag is a traditional product made of PVC. PVC is used to make all kinds of imitation leather, luggage bag and sports products, such as basketball, football and football. It can also be used to make uniforms and belts for special protective equipment. PVC fabrics for clothing are generally absorbent fabrics (without coating), such as ponchos, baby pants, imitation leather jackets and various rain boots. Polyvinyl chloride is used in many sports and entertainment products, such as toys, records and sporting goods. Polyvinyl chloride toys and sporting goods have a large growth. It has an advantage because of its low production cost and easy molding.
9. PVC coated products
Artificial leather with substrate is made by applying PVC onto cloth or paper and plasticizing it above 100 ℃. PVC and additives can also be calendered into a film, and then pressed with the substrate. The artificial leather without substrate is directly calendered into soft sheets of a certain thickness by calender, and then pressed with patterns. Artificial leather can be used to make suitcases, bags, book covers, sofas and car cushions, as well as floor leather, which can be used as paving materials for buildings.
10.PVC foam products
When the soft PVC is mixed, a suitable amount of foaming agent is added into the sheet to form foam plastic, which can be used as foam slippers, sandals, insoles, and shockproof cushioning packaging materials. It can also be formed into low foaming rigid PVC plates and profiles based on extruder, which can replace wood. It is a new building material.
11. PVC transparent sheet
PVC is mixed, plasticized and calendered into transparent sheet by adding impact modifier and organotin stabilizer. Thermoforming can be used to make thin-walled transparent containers or vacuum blister packaging. It is an excellent packaging material and decorative material.
12. Others
Doors and windows are assembled with hard special-shaped materials. In some countries, it has occupied the market of doors and windows together with wooden doors, windows and aluminum windows; Imitation wood materials and steel building materials (North and seaside); Hollow container.