China's circulating fluidized bed power generation technology has entered a new era

Since the advent of circulating fluidized bed (CFB) power generation technology, it has been widely used in the world, and large-capacity circulating fluidized bed generator sets have been adopted
by China's power generation enterprises.
The 600,000-kilowatt-level circulating fluidized bed power generation technology has been in operation for one year, and its advantages have been highlighted, and various performance indicators are comparable to pulverized coal furnace power generation technology
.
This technology has comprehensive competitive advantages in fuel selection, control of pollutant emissions, comprehensive utilization of ash residue, etc.
, and is worth further promoting
in today's increasing environmental pressure.

"With the accumulation of experience in the world's first 600,000-kilowatt supercritical circulating fluidized bed power station in China for more than a year, and the various advantages highlighted by other grades of circulating fluidized bed power generation technology in recent years, it can be asserted that China's circulating fluidized bed power generation technology is entering a new era
.
" At the "2014 Annual Conference on Circulating Fluidized Bed Power Generation Technology" held by China Power Science and Technology Network in late August, Wei Yupu, CEO of China Power Science and Technology Network, said
.

China has become the country
with the largest number of circulating fluidized bed generator sets in operation and the largest installed capacity in the world.
In recent years, with the accumulation of design experience, the improvement of manufacturing level and the maturity of operation technology, circulating fluidized bed power generation technology, especially 300,000 kilowatt circulating fluidized bed power generation technology, has shifted from the early pursuit of reliability indicators to the pursuit of economic indicators and environmental protection indicators
at the same time.

The overall performance can compete with pulverized coal furnace units

Thermal power generation is the main power generation mode in China, and the power station boiler as one of the host equipment of the thermal power station, develops with the development of China's thermal power industry
.
Power station boilers mainly include pulverized
coal furnace and circulating fluidized bed boiler.

In the "Key Core Technology Research and Development" part of the "Twelfth Five-Year Plan for the Development of Clean Coal Technology Science and Technology", the "efficient and clean coal-fired power generation" mentions: 600,000 kilowatts of high-parameter ultra-supercritical circulating fluidized bed boiler industrial equipment technology research, manufacturing and engineering demonstration, technical and economic indicators close to the same capacity similar to fuel pulverized coal furnace units, reaching the international leading level
.

On April 14, 2013, the world's first 600,000-kilowatt supercritical circulating fluidized bed unit independently developed, designed and manufactured by China was completed and put into operation
in Baima, Sichuan.
This unit is currently the world's largest single-capacity and most technologically advanced supercritical circulating fluidized bed unit, representing the highest level
of circulating fluidized bed power generation technology today.

"Judging from the operation practice of more than 20 circulating fluidized bed generator sets that have been put into operation, the circulating fluidized bed units can be as reliable
as pulverized coal furnace units.
" Liu Zhiqiang, deputy general manager of Shenhua Guoneng (Shendong Power) Group Company, said, "In view of the success of the 600,000-kilowatt supercritical project, we are applying for a 660,000-kilowatt ultra-supercritical circulating fluidized bed unit demonstration project
.
"Circulating fluidized bed power generation technology is capable of burning all types of coal, especially low-grade and low-quality coals
that are inexpensive.
According to a survey in the United States, a circulating fluidized bed unit with a capacity of 600,000 kilowatts can save $84 million
a year in fuel costs compared with a pulverized coal furnace unit.
According to German survey statistics, in Europe, the availability rate of circulating fluidized bed units that burn low-rank coal is higher than that of pulverized coal furnace units
that burn low-rank coal.

"Circulating fluidized bed power generation technology has developed to the level of large-capacity supercritical and can compete
with pulverized coal furnaces to a certain extent.
" In recent years, Professor Mao Jianxiong of the Department of Thermal Engineering of Tsinghua University has been working on the topic of "Comparison of Large-capacity pulverized coal furnaces and circulating fluidized bed boilers that burn low-rank coal", and at the above meeting, he proposed: "When selecting a power station boiler with a large capacity of burning low-rank coal, under the conditions of boiler capacity of 600,000 kilowatts and below and steam temperature of 600,000 kilowatts and below, the circulating fluidized bed power generation technology is not lost to the pulverized coal furnace power generation technology in terms of technology and economy.
" It's
just that circulating fluidized bed power generation technology has just begun to enter the large-capacity and supercritical level, and it still needs to spend a lot of effort to accumulate experience, but the future must be bright.
”

"Ultra-low emissions" have become a new hot spot in research and application

In 2013, the flue gas nitrogen oxide emission comprehensive control process technology independently developed by China Huaneng Group and suitable for circulating fluidized bed boilers was successfully applied in the 330,000 kW circulating fluidized bed boiler of Huaneng Baishan Coal Gangue Power Plant and the 300,000 kW circulating fluidized bed boiler of Qinhuangdao Qinthermal Power Generation Company, with an average denitrification efficiency of 82.
7
%.
This technology is the first in the world to be used
in a 330,000-kilowatt circulating fluidized bed boiler.
Under the background of the implementation of the latest "Air Pollutant Emission Standards for Thermal Power Plants" (GB13223-2011) of the national energy conservation and emission reduction policy, what kind of transformation technology route is chosen by the circulating fluidized bed unit to achieve the emission of sulfur dioxide and nitrogen oxides has become an urgent topic
to be solved in the industry.

The "Twelfth Five-Year Plan for the Development of Clean Coal Technology Science and Technology" clearly states: "Carry out research on key technologies and equipment of 5~300,000 kilowatts energy-saving, ultra-low emission circulating fluidized bed boilers, and apply them to industrial demonstration
.
" "In the face of increasingly stringent environmental emission targets, circulating fluidized bed power generation technology is facing challenges and bringing new development opportunities
.
" At present, the rise of 'ultra-low emission', 'near-zero emission' and other booms in domestic coal-fired power plants, its scientificity and rationality are temporarily ignored, from the perspective of circulating fluidized bed generator sets to achieve 'ultra-low emissions', compared with pulverized coal furnace generator sets, it has unique advantages
。 Xiao Ping, vice president of China Huaneng Group's Clean Energy Technology Research Institute, told China Electric Power News that "the circulating fluidized bed generator set can adopt two-stage desulfurization in the furnace + desulfurization outside the furnace to achieve ultra-low emissions of high-sulfur coal; Low nitrogen combustion + SNCR in the furnace can control nitrogen oxide emissions to less than 50 mg/m³; Due to the use of furnace desulfurization, the risk of low-temperature corrosion of the tail heating surface is greatly reduced, and the exhaust gas temperature can be designed to be lower, which is more conducive to achieving low and low temperature dust
removal while improving boiler efficiency.
According to Xiao Ping, the circulating fluidized bed power generation technology has a low concentration of nitrogen oxides due to the use of staged combustion and low-temperature
combustion technology.
According to the "Air Pollutant Emission Standards for Thermal Power Plants", some CFB units can meet the requirements without transformation or simple furnace transformation and combustion optimization adjustment, and for some units that exceed the standard and newly built units, SNCR denitration technology is adopted, and the denitration efficiency can reach 60%~85%, achieving standard emissions, while the construction period is short, the investment cost is low, and the operation effect is good
.

"Circulating fluidized bed units rely only on furnace desulphurization and low-temperature combustion, which is already difficult to meet strict emission requirements
.

Under the new "Air Pollutant Emission Standards for Thermal Power Plants", circulating fluidized bed units need to carry out coordinated control of flue gas pollutants to achieve standard emissions
.
The technical route of flue gas circulating fluidized bed desulfurization + SNCR denitrification + bag dust removal is a more feasible control scheme
at present.
Long Hui, deputy director of the R&D center of China Power Consulting Group, said
at the meeting.

If the emission standard is met, it should enjoy the denitration electricity price

"We have also consulted with relevant ministries and commissions of the state, and the nitrogen oxide emission of circulating fluidized bed units is entitled to denitration electricity prices
.
However, in terms of specific implementation, some provinces do not recognize the denitration electricity price for denitration power plants in circulating fluidized bed
furnaces.
In recent years, Liu Zhiqiang has been highly concerned about
the nitrogen oxide emission standards of circulating fluidized bed units but cannot implement denitration electricity prices.

Shenhua Guoneng (Shendong Power) Group Company, where he works, is the power generation group
with the largest number of circulating fluidized bed generator sets in China.

The reporter learned from relevant channels that various places do have different policies for circulating fluidized bed units when implementing denitration electricity prices
.
For example, the Notice of the Hunan Provincial Price Bureau on the Trial Denitration Electricity Price of Coal-Fired Units in the Province points out that "in the coal-fired generator set, the nitrogen oxide emissions of the unified coal-fired generator unit have installed denitration facilities, have online monitoring functions and are operating normally, and the nitrogen oxide emissions of the circulating fluidized bed unit have met the national environmental protection requirements, and the generator sets that have passed the acceptance by the national or provincial environmental protection department will implement the denitration markup
.
" The relevant regulations issued by the Anhui Provincial Price Bureau only mention "coal-fired generator sets with denitration facilities, online monitoring functions and normal operation" units, and do not mention "circulating fluidized bed units"
.

"The price of electricity for desulfurization and denitrification should be determined by whether the emissions meet the standard, not on the technology adopted
.
" Liu Zhiqiang suggested that the environmental protection department should use the actual emission value of the circulating fluidized bed power plant to confirm whether its flue gas emissions meet the standard
.

Zhang Jiwu of Guodian Yuyuan Power Generation Co.
, Ltd.
suggested that the provincial power grid companies give circulating fluidized bed units as much as possible no peak shaving or small peak shaving to protect boiler equipment
.
"We still need to improve many aspects, such as the inability of a single induced draft fan to operate, the high coal consumption of the unit's power supply, and the difficulty of near-zero emission of environmental protection indicators
.
" Lei Xiujian, chief engineer of Sichuan Baima Circulating Fluidized Bed Demonstration Power Station Co.
, Ltd.
, said
.

With the decreasing reserves of high-rank coal, low-rank coal, especially lignite, is an important source of thermal coal in the future, coupled with its price advantage, in the large-capacity high-parameter supercritical power station boiler market, although the circulating fluidized bed unit has not really entered, but for the coal power market burning low-rank coal and low-quality coal, the advantages of circulating fluidized bed unit will gradually appear
.

"Circulating fluidized bed power generation technology is a developing technology, a technology
that keeps pace with the times.
" Huang Zhong, China Huaneng Group Clean Energy Technology Research Institute, believes that "the causes of the problems of circulating fluidized bed units are very complex, and it is necessary to avoid entering the misunderstanding of 'headache and pain' or 'taking care of one and losing the other', and make full use of existing experience, deeply analyze the deep-seated technical reasons behind the phenomenon and problems, and comprehensively consider various factors
such as design and manufacturing, main engine and auxiliary equipment, installation and maintenance, operation and maintenance.
" ”