Comprehensive feedback from industry experts and users, although currently only four months away from the full implementation of heavy-duty diesel vehicles in the country, and most countries have actually implemented the four countries, but the market supply of car urea is still not enough. Part of the reason for this is the lack of national standards for vehicle urea.
When the reporter visited the user, it was found that the two sources for the purchase of urea for vehicles are urea filling stations and small-packed urea sold in the market, such as barrels and bags. Due to the lack of dedicated urea filling facilities, users generally choose to purchase urea in small packages.
The shortage of urea filling stations was a common concern in the industry. For the National IV diesel vehicle using the SCR technology line, urea has become a consumable product and needs to be filled at any time. In other words, urea, like diesel, is the “second fuel†for the National IV diesel vehicle, but now urea filling stations are still scarce compared to gas stations. Several commercial vehicle companies had conducted a survey earlier this year. Among the 688 gas stations surveyed, only six supplied urea, of which only one gas station had urea filling machines, and five supplied small-package urea. The supply rate of urea in the gas stations in the surveyed area was very low, only 1%. In the 113 large auto parts markets or service stations in 54 prefecture-level cities surveyed, only 43 dealers provided In small packages of urea, the supply rate of urea was 38%.
It is not difficult to see from this survey that even in the filling stations with dedicated urea filling facilities, small-package urea is still the main force of urea supply. The relevant person in charge of the company's production of urea for automobile yasehuanhua said that the shortage of filling stations is an objective situation. There are many ways to build urea filling stations, and cooperation with gas stations is one of the ways to build an independent filling station. In one form, after specific standards for urea-filled special facilities for vehicles are clearly defined, China can use two methods to build in parallel and increase the number of filling stations in a short period of time.
The recent survey of the automotive urea market by the Secretary General of the Commercial Vehicles Division of the Federation of Trade Unions Yang Zaijun also showed that the urea used by most users was small-packaged urea. Although the quality of urea used in the market is uneven, urea prices are still rising sharply. This shows that vehicle urea is indeed in short supply in the market.
Some industry experts believe that the cause of the shortage of urea in vehicles is not the lack of production, but the lack of national standards for urea. Because there are no national standards, some companies are hesitant to enter the urea production industry or what kind of technology is used to produce urea, which reduces production. Some poor-quality urea products enter the market and lead to a shortage of qualified urea supply. The difficulty in purchasing qualified urea increases and the price increases. In addition, the unclear standard for urea-specific filling facilities will also dampen investors’ enthusiasm for investing in such facilities.
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Characteristic and performance analysis of main parts of generator
Stator:
Stator consists of base, stator core and stator windings.
The base is welded by steel plate, the structure is light and sturdy, and the base is divided into many air inlet and outlet zones in the axial direction;
Stator coil:
It is stacked by strands of copper wire covered by polyester glass fiber, with half-unit type and basket shaped structure (parts of stator coils use transposition structure). The insulation grade of the stator coil is F grade. The stator coil is shaped by continuous wrapping and mould pressing with mica tapes. The coil end is firmly tied up to the support and the bundling ring with unidirectional tapes or dacron-glass ropes thus the turbo-generator unit became highly resistant towards sudden short-circuit conditions.
Stator core:
Stator core is punched and stacked by cold rolled non-oriented, high permeability, low loss high-quality silicon steel sheet, both sides of the silicon steel sheet are coated with a solid insulating film to prevent short-circuit between the stator core pieces to reduce eddy current loss.
Rotor:
The rotor is composed of shaft, coil, center ring, shroud ring and fan ring etc. The rotor coil is made of cold-drawn flat copper wires, and processed by oxygen-free annealing. The rotor coil of generator with 50MW and above is welded together by silver-bearing cold-drawn copper wires and adopts F grade insulation.
The shroud ring at rotor coil end is made of non-magnetic steel. Both ends of the rotor are equipped with centrifugal fan or axial flow fan with paddle fan blade which is forged by high-strength aluminum alloy.
Rotor machining:
The generator shaft is forged from an integral high-quality alloy steel and has an axial groove formed thereon for fitting a rotor coil and an air groove or a crescent groove is made in the large tooth to enhance the cooling of the main body and the coil end. The slots are processed by special machine for generator rotor processing, Tacchi high precision horizontal slotting and milling machine made in Italy, to ensure the high efficiency of generator.
The generator rotor must be subjected to high-speed dynamic balancing experiment and dynamic impedance experiment before delivery to verify the mechanical strength of the rotor and ensure excellent inter-turn insulation of the rotor windings.
(2)Model
Mainly produce the following model Steam Turbine Generator and the specifications are as follows:
Voltage(KV) Frequency(HZ) Power(MW)
2 poles Steam Turbine generator 6.3-3.8 50 3-60
6.6-13.8 60
4 poles steam turbine generator 0.4/0.69 6.3/6.6 10.5/11 50 0.5-30
0.4-11 60
QNP steam turbine generator uses closed-loop air self-circulation ventilation.
The rotors of turbo-generator under 50MW adopt indirect ventilation cooling method;
The rotors of 50MW and above turbo-generator is directly ventilated and cooled; an auxiliary groove is machined under the rotor winding trunking; air vents are machined on the rotor windings; with the action of the fan head and the centrifugal pressure head of the air vents, the rotor windings are directly cooled by air from the auxiliary groove and air vents.
(4)Excitation mode
QNP's steam turbine generator can adopt static silicon controlled type, two-pole AC brushless excitation and three-pole AC brushless excitation, three kinds of excitation mode.
(5)Insulation system
Adopt class F insulation materials and insulation structure, during the running time, assess the system according to class B insulation grade, meanwhile some margin has been kept.
(6)Design and acceptance criteria
Design, manufacture, inspection are carried out according to the relevant national standards, at the same time can meet the International Electrotechnical Commission IEC34-1 latest standards. According to customer`s requirements, QNP`s steam turbine generator can also be designed, manufactured and accepted according to ANSI, NEMA and other international standards.
(7)Technical Performance Analysis
1.Output margin
The series of steam turbine generator of QNP keeps 10% output margin.
2.Loss and efficiency
The steam turbine generator of QNP optimized the design and farthest minimized the additional loss and wind abrasion of generator under no-load and short-circuit condition, improved the efficiency of the generator, in general, QNP steam turbine generator`s efficiency is 0.2% higher than domestic similar models in this industry. It is higher than the national efficiency standard on the same capacity level. For example: QNP 15MW steam turbine generator`s efficiency value can reach 97.65%, and the national standard value is 97%.
3.Running reliability
QNP's steam turbine generator adopts advanced manufacturing technology, especially the rotor`s overspeed test uses high-speed dynamic balancer, rotor`s balance precision has been greatly improved, and the rotor`s vibration value is decreased. So that the steam turbine generator`s running availability factor has been improved, and the unit`s forced outage rate is decreased. At present, the availability factor of the steam turbine generator can reach about 99%, and the forced outage rate fell to 0.04% to 0.4%. Overhaul interval is up to 5 years. And the unit life can reach to 35 to 40 years.
Model meaning
QFWD-3-2A
QF Steam turbine generator
W W means brushless, without W means static silicon controlled
D D means double support, without B means single support
3 Rated power
2 2 means two poles and means the rated rotation speed is 3000 r/min
4 means four poles and means the rated rotation speed is 1500 r/min
A means the design serial number: A.B.C.D
Steam Turbine Generator,Biomass Generating,Biomass Generation,Biomass Power Generation
Shandong Qingneng Power Co., Ltd. , http://www.steamturbine.be