Speech 2 PR China. Energy Saving of Coal-fired Power Plant

Transcription

1 Day 1 Monday 15 October 2007 Session 5: Clean Coal Power Generation Speech 2 PR China Energy Saving of Coal-fired Power Plant Mr. Jin Donglai Deputy Director Safe and Operation Department China Power Investment Corporation PR China

2 JinDonglai In 1982, Mr. JinDonglai, currently a senior engineer, graduated from North China Institute of Electrics as a Master of Science in the major of thermal power kinetic. From , he acted as teaching assistant in NCIE. From , he worked in the Department of Safety Supervision and Production in the Ministry of Electrics and the Department of Electrics under the Ministry of Energy. From 1998 to 2002, he was Vice Director and Director in the Power Transmission Operation Department of the State Grid. From 2003 to 2005, he was Vice Manager of the Department of Safety & Production in China s Electrics Investment Co. From 2005 to 2007, he served as Vice General Manager in the Jiangxi Branch of CEIC and from 2007 to present, he has been acting as the Vice Manager of the Dept. of Safety in CEIC. His primary interest of research includes overseas studies of electrics, Safety Management in power plant and the CPC s role in Technology Management and Production. Awards: Mr. JinDonglai was the third prize winner of 98 Science and Technology Award given out by Ministry of Energy for the research project entitled Testing Characterizations of Two Dimensional Corona Field and Its Applications. In 1991, he won the third prize of such an award again for studies on nuclear and coal sourced power generation. In 1996, he won the second prize of Science and Technology Award given out by Ministry of Electrics for a project related to the upgrading and modernization of coal-fired power generation sets. From 1999 to 2000, he presided over the revision and formulation of Twenty-five Key Requirements for the Prevention of Severe Accidents in Electric Power Generation. From , he presided over the formulation of the State-level Principles to the Overhaul of Equipments in Electricity Generating Enterprises, officially carried out on 1 st June, In 2006, he won the second prize of Science and Technology Award given out by CEIC for The Application of A New Model of Internal Counter Flow Nozzle Button on 150MW Atmospheric Circulating Fluidized-bed Units.

3 Energy-saving Technologies of Thermal Power Plants Jin Donglai China Power Investment Corporation 15 October 2007

4 Foreword In 2006 China's total electricity generation is TWh, including TWh of thermal power, which accounted for 83% of the country's total electricity generation, and 416.7TWh of hydropower, 14.7% of the country 's total electricity generation. In recent years, thermal power generation has been developing rapidly with an annual growth rate of about 15%. By the end of 2006, the country's total installed generating capacity reached 622 GW, with 484 GW of thermal-power capacity which accounts for 77.82% of nation s total capacity and 129 GW of hydropower with a ratio of 20.67%.

5 Foreword China's total installed generating capacity and total electricity generation are both ranking the second in the world, and maintaining a relatively high growth rate in these years. In the next five to ten years, the ratio of China's installed generating capacity of thermal power will remain high.

6 Foreword Although China's energy reserves are rich, but per capita availability of energy resources is low. China's fossil energy reserves exploitable are proven to be more than 823 billion tons of standard coal. And remaining economic recoverable reserves is of billion tons of standard coal which accounts for 10% of the total world's energy resources and proven coal resources, amount to billion tons, which are ranking the third in the world. And the direct use of proven raw coal reserves is billion tons. But it is only about 50% of the world per capita average. Oil and natural gas reserve per capita is lower than the world average.

7 Foreword China is the world's second largest energy producer and consumer. Energy consumption mainly relies on domestic supply and energy self-sufficiency rate is 90%. In 2006, China's raw coal production is 2.37 billion tons; crude oil production billion tons; natural gas production billion cubic meters. Raw Coal consumption is 2.3 billion tons, of which, billion tons are burned by thermal power units with a capacity of 6000kW and above, which accounts for 48.19% of the total coal consumption.

8 Foreword According to the current coal mining and utilization, the coal reserves in China can only be used for less than 100 years, therefore, China's coal resource exploitation and sustainable use are facing serious problems.

9 Foreword In the Proposals on the 11th Five-year Plan for National Economic and Social Development Plan, it is clear that the conservation of resources is the country s basic policy. Our country s energy-saving guidelines are developing a scientific development concept as a guide, adhere to the principle of energy conservation priority, changing the mode of growth, adjusting structure of economy, accelerating technological progress as fundamental, improving law systems and using energy efficiently to promote the sustainable economic and social development. Our country will put energy-saving and consumption reduction as the important work ahead and our goal is to reduce 20% of unit GDP energy consumption in the period of "11th Five-Year Plan".

10 Foreword According to the statistics of thermal power generation in 2006, net coal consumption rate of thermal power generation is 366 g/kwh, which is 30 g/kwh higher than the average level in developed countries, about additional 67 million tons of standard coal or nearly 100 million tons of raw coal every year will be burned. As thermal power industry providing secondary energy for the society, improving the utilization efficiency of coal, promoting energy-saving and consumption reduction vigorously and extending coal consumption time are important tasks ahead.

11 Status Of Energy Consumption And Analysis (1) The status of thermal power energy consumption Since the beginning of the 21st century, the nation s technology and equipment of thermal power plants has developed quite rapidly. Supercritical and ultra-supercritical thermal power generating units have been put into operation in succession. Large capacity, high efficiency and environment-friendly generating units are gradually becoming the main stream. According to the preliminary statistics, 62 generating units with a capacity of 600 MW each and 349 generating units with a capacity of 300MW each were put into operation in China in 2005 alone. However, 200 MW,125MW and even lower capacity units still account for about 40% of total thermal power generating capacity. The average capacity of thermal power generating units is only 98MW in 2005.

12 Status Of Energy Consumption And Analysis According to the statistics, in 2006 China's net coal consumption rate of thermal power plant is 366 g/kwh. But in some developed countries, it is only 335 g/kwh. That means producing every 1kWh of electricity will consume about 31 grams of standard coal in China more than developed countries. According to the statistics of 2006 thermal power generation, China consumed more than 67 million tons of standard coal just in that year. Contrast to the developed countries such as Japan (299 g/kwh), South Korea (300 g/kwh), Italy (303 g/kwh), the net coal consumption rate was about 60 g/kwh higher in China, more than 130 million tons of standard coal a year will be wasted.

13 Status Of Energy Consumption And Analysis In different types of units, there are obvious gaps between our country and the developed countries. For instance: ultra-supercritical power units with a capacity of 600 MW and above, the net coal consumption rate is g/kwh, 5-10 g/kwh higher than the developed countries; supercritical thermal power units with a capacity of 600 MW and above, net coal consumption rate is g/kwh, g/kwh higher than the developed countries; sub-critical power units with a capacity of MW, the net coal consumption rate is g/kwh, 15 g/kwh higher compared with the advanced level; for 200 MW and below units, the net coal consumption rate is g/kwh, g/kwh higher compared with the advanced level and 20% to 40% higher than large capacity units.

14 Status Of Energy Consumption And Analysis (2) The main reasons for high energy consumption of thermal power units Performance of main equipment of thermal power plants can not reach the design standard The main power equipment design level of China's early 200MW, 300 MW thermal power generating units is not high, and it lacked the necessary testing and optimization. In addition, there are wide gaps between our country and the developed countries in material and the manufacturing process. These all caused the result that main equipment cannot perform design specifications.

15 Status Of Energy Consumption And Analysis System design can not attain optimization First, major auxiliary equipment such as mill, delivery motor and blower lack optimization, thus inadequate or excessive output often happens. Second, thermal power system and air system design are usually unreasonable, resulting in increased energy loss. Third, new technologies are not used widely.

16 Status Of Energy Consumption And Analysis The level of economic operation is not high First, electric dispatch is not scientific and economic. Second, some operators are lack of operation skill and experiences, furthermore, equipment reliability is poor, so optimization and adjustment are difficult. Third, fuel price and quality changes frequently, and boiler system have some serious leakage, which lead to difficult adjustment.

17 Status Of Energy Consumption And Analysis Fuel supply is unstable One of the biggest barriers which affect the domestic boiler combustion and energy consumption is unstable fuel supply. Due to the differences between the design coal and the actual coal used, the condition of boiler combustion deteriorates. As a result, the chance of boiler coking even flameout increases. Meanwhile, problems such as wear of boiler, equipment reliability reducing and increasing of energy consumption appear.

18 Status Of Energy Consumption And Analysis Some problems occur in new units In past few years, more and more power units are under construction, as a result, design company, manufacturing company and construction company are in high-load. Such condition affects the design optimization and the quality of manufacturing and installation. While the units are put into operation, they cannot reach the designed target and meet such severe problems as abnormal turbine flow installation space, shaft seal leaking, poor vacuum tightness and low cylinder efficiency.

19 Status Of Energy Consumption And Analysis There are gaps in management First, energy-saving mainly relies on administrative orders or the letters of responsibility signed by government and enterprises, that lacks of legal and market means. Second, individual enterprises are short of sufficient energy-saving awareness. They do not put energy conservation into an important position. Third, the intensity of energy-saving examine is not enough, and the atmosphere of full participation has not been formed.

20 Main Energy Saving Strategies Of China Although the thermal energy consumption indicators in our country are much higher than the world advanced level, but by strengthening conservation and the legal system, changing the management philosophy, upgrading and restructuring the implementation of thermal power technology, using the advanced energy saving technology and perfecting the policies to support and enhancing the management of energy-saving, energy consumption indicators of power units in China must be remarkably reduced.

21 Main Energy Saving Strategies Of China (1) Adjusting the structure of electricity industry and developing advanced technology units. First, we should focus on the development of 600 MW and above the supercritical units which are more high-efficiency, energy-saving and environmentally friendly. These units have the capacity of MW, the main steam pressure of MPa, and the temperature reaching C. Super-heater and re-heater use P92, P125, C91 refractory steel pipe; Boiler efficiency is 93% -94%; Turbine uses advanced design techniques; Blades have the efficient use of the entire 3D design; Turbine thermal efficiency reached 43%-47% and coal consumption is g/kwh.

22 Main Energy Saving Strategies Of China Second, we strengthen the work of "developing large units and stopping small units " and speed up shutting down small thermal power generating units. 125MW and smaller units follow the implementation of substituting by large units. In the same load level, large units can save 30% to 50% amount of coal. At the end of the "11th Five-Year Plan", our country will shut down more than 50,000 MW small coal-fired units. Third, we must energetically develop new energy and recycle energy generation. Such as nuclear power, solar power, hydropower, wind power, and so on. We shall gradually increase the generation ratio of clean energy.

23 Main Energy Saving Strategies Of China (2) Implementing modernizing modification of the turbine system and improving turbine efficiency. First, we should strengthen the work of equipment modification especially in 200 MW and 300 MW turbine power unit flow modification, this is an effective measure of reducing energy consumption. Due to the design and manufacture limitations, generating units put into operation before the 1990s usually have the problems of timeworn turbine blade, inefficient cylinder, poor adaptability for variable load and high heat consumption. Nowadays the application of advanced three-dimensional blade technology and advanced processing technology can reduce the blade loss effectively and improve the steam engine's efficiency. After the modification, 200 MW and 300 MW steam turbine units can improve the efficiency of high pressure cylinder by 3-6%, middle pressure cylinder by 2-3% and low pressure cylinder by 6-10%. At the same time the net coal consumption rate can reduce g/kwh.

24 Main Energy Saving Strategies Of China Second, we should implement the modification of the steam heating system mainly including main steam seal optimization and the redundant thermal system simplification. Third, we should improve the condenser and cooling water system including optimizing the design of the condenser pipe structure and layout; using titanium or stainless steel tube instead of the traditional pipe; changing the structure and stuffing of the core of cooling tower.

25 Main Energy Saving Strategies Of China (3) Implementing modification of variable frequency adjusting for large motors and reducing service power consumption rate. Excluding the pulverizing system, main rotation auxiliary equipment such as pumps and fans consume about 50-70% of service power consumption in a power plant. Since the peak-load operations of a power unit are more frequently, the running time of pumps and fans in low load condition increases, the system has more energy loss and lower efficiency. So now modification of variable frequency adjusting method has been introduced. On the basis of no-changing the original structure of pumps and fans, we install a high-voltage converter on them to achieve speed adjustment which can save 20% to 35% of energy.

26 Main Energy Saving Strategies Of China (4) Reducing boiler heat loss and improving boiler efficiency. First, modify burner of boiler in order to gain more adaptability and adjustability, which can prevent coking characteristic and lower non-oil stable combustion characteristics. Second, modify soot-blowing system of boiler and ensure the normal operation in order to improve heat transfer effect of heating surface. Third, modify Rotary air pre-heater especially which s leakage rate is more than 20% to reduce air leakage rate of the boiler. Change the sealing system to dual-seals technology and increase heat transfer sections from 24 to 48, thus air leakage rate can reduce 5-7%.

27 Main Energy Saving Strategies Of China (5)Using non-oil (less oil) ignition technology and reducing fuel consumption. Plasma oil-free ignition has a very successful application in China and has achieved obvious results. The theory of plasma oil-free ignition is that working gas is ionized when it flow through between the cathode and anode voltage field. The plasma arc which s temperature reached thousands of degrees, forms plasma torch and is injected into an air duct. When the air heats the coal, coal particles are immediately ignited. Currently researchers have developed a new technology which is called "high temperature air" oil-free ignition. It can consecutively produce high-temperature air up to 1,000 C after power input for more than 3 minutes and ignite air and coal. In addition, several domestic less oil ignition technologies have gain fairly well effects and make a significant contribution to oil conservation in electric fields.

28 Main Energy Saving Strategies Of China (6) Using optimization technology and improving power generating equipment operating parameters and economic indicators. First, equip with surveillance information system (SIS). In practical, workable principles, combined with comprehensive optimization results of the trials, make optimum operation of the power generating equipment, running curves and operating parameters. Help operating personnel to operate and optimize energyloss analysis including the main parameters such as the main steam pressure, the main steam temperature, re-heater temperature, flue gas temperature, flue gas oxygen content,pump service power consumption rate, fly ash carbon content, the service power consumption rate, vacuum, efficiency of high-pressure cylinder, efficiency of middle-pressure cylinder, ultimately water temperature, the temperature difference of heaters, super-heater desuperheating water flow, re-heater desuperheating water flow.

29 Main Energy Saving Strategies Of China Second, implement optimal load distribution in the power units. achieve optimum plant coal consumption targets according to he best unit load distribution in the circumstances of certain load. Third, the 200 MW units should equip with real-time management optimization system.

30 Main Energy Saving Strategies Of China (7)Researching and using desulfurization equipment power-saving technology to reduce the energy consumption of desulfurization equipment. First, according to coal providing condition, implement coal blending measures to maintain the sulfur stability of the coal into the furnace. Second, according to unit load and the sulfur content, readjusting and optimizing the operation mode of recycle slurry pump. Third, take effective soot blowing measures to prevent GGH jam and maintain desulfurization system in low pressure loss. Fourth, improve the quality of limestone.

31 Concluding Remarks Through large-scale construction of 600 MW and above large-capacity supercritical units which are efficient, energy-saving and environmentfriendly; implementing "developing large units and shutting down small units " policy and shutting down small thermal power units; using energy-saving technological innovation to modify 200MW and above the units; fulfilling the various measures of economic operation, our country s energy consumption indicators will be significantly improved. In 2010, the net coal consumption rate of 300 MW capacity and above thermal power units in China will be close to the advanced international level and contribute to the objectives of the "11th Five-Year Plan" by 20% reduction of unit GDP energy consumption.

32 Thanks