Discussion on energy saving system technology and application of gas heating boiler room

Abstract: new energy-saving technologies of gas heating, such as climate compensator, flue gas condensation heat recovery device and time-sharing control, are introduced This paper enumerates two typical projects of energy-saving system in gas-fired heating boiler room, and makes a comparative test before and after putting it into the energy-saving system, and makes an analysis of energy-saving and economic benefits Key words: energy crisis, gas heating, energy saving and economic benefits 1 Preface there are four heating modes in Beijing: urban heating network heating, regional boiler room heating (including coal, gas, oil, electric boiler), clean energy household heating (natural gas wall mounted furnace, electric heating) and small stove heating Among them, the main heating methods are coal, heat and gas heating In order to ensure and improve the quality of atmospheric environment and promote and use clean energy, Beijing is changing coal-fired boiler into gas-fired boiler Beijing's coal-fired boiler heating has a history of several decades, while gas-fired boiler heating started in 1997 when natural gas came to Beijing The actual operation is only a few years old, lacking experience in design and operation and many problems Natural gas is a very valuable energy, especially in the last year, there was a shortage of natural gas Therefore, how to realize the energy saving of gas boiler heating has become a hot issue of great concern In order to achieve the energy saving of gas-fired heating boiler system, we need to start from all aspects of design, construction and operation This energy-saving system can not only reduce the gas cost, extend the service life of the boiler, ensure the safe and stable operation of the gas-fired boiler, improve the level of equipment management, but also solve the problem of high gas consumption and more condensed water in the boiler The "GBC gas heating and energy saving system" developed by Beijing JinFang heating and ventilation energy saving technology company has been applied in several heating districts, such as Madian South Village, Heping Street West Garden and Boya West Garden, and more than one hundred boiler rooms have a total area of more than 10 million square meters The energy saving rate is more than 15% after the test by Beijing energy conservation and environmental protection center! The company has solved the problem of 1.2 million square meters hydraulic imbalance in Beijing Wangjing community, completed the energy-saving technology transformation project of the heating plant of Beijing Shangdi Information Industry base, and hundreds of projects such as the 11th Five Year Plan of heating in Changping District, and achieved obvious economic and social benefits 2 Energy saving technology of gas heating 2.1 energy saving technology of gas heating 1: the heat consumption of climate compensation system buildings is always changing due to the influence of outdoor temperature, solar radiation, air humidity, wind direction, wind speed and other factors In order to keep the indoor temperature constant (such as 18 ℃± 2 ℃) or meet the user's requirements under the conditions of the above factors, the supply and return water temperature of the heating system shall be adjusted according to the changes of outdoor meteorological conditions during the whole heating period, so as to make the heat supply capacity of the boiler, the heat release capacity of the heat dissipation equipment consistent with the heat demand of the building, and prevent the room temperature of the user from being too low or too high The phenomenon Through timely and effective operation and regulation, we can achieve Zui energy saving to a large extent on the premise of ensuring the heating quality The change of the outdoor temperature determines the heat demand of the building and the energy consumption The operation parameters must be adjusted every moment with the change of the outdoor temperature, so as to ensure that the heat supply of the boiler room is consistent with the heat demand of the building Only in this way can Zui achieve large-scale energy saving Each boiler house should operate according to its own operation curve, which is the Zui best operation curve of the boiler house The climate compensation system is a system that provides the boiler room with Zui optimal operation curve The system can save more than 5% energy by adding climate compensation device 2.2 gas heating energy saving technology II: flue gas condensation heat recovery system Through the analysis of flue gas composition of various fuels, the following characteristics are found: the proportion of water vapor volume in flue gas composition of various fuels is: natural gas 20%, oil 12%, coal 4% Why is the proportion of water vapor volume Zui in the flue gas component of natural gas large? Because the main component of natural gas is methane (CH4), because it has a large number of hydrogen elements, when it is burned, it combines with oxygen to produce a large number of water vapor One kilogram of water vapor carries 2400kj of heat A 0.7mw boiler generates 30-40kg of water vapor per hour, which is roughly equivalent to taking 0.7mw of heat away in 25-33 hours Therefore, the heat loss is very large It is necessary to recover this part of heat, improve the thermal efficiency of the boiler and reduce the gas consumption Foreign countries have long recognized the seriousness of this problem At present, the exhaust gas temperature has been generally reduced to 70 ℃, and Zui is as low as 40 ℃ Some foreign propaganda lists of condensing boilers show that the boiler efficiency can reach 104%, which is to make full use of this part of energy The dew point temperature of flue gas is about 58 ℃ As long as it contacts the medium below the dew point temperature, it will condense into water and release a lot of heat The heat is composed of two parts: (1) physical sensible heat: it is realized by reducing the smoke temperature, and the smoke exhaust temperature can be controlled at 70-80 ℃ After testing, reducing the flue gas temperature by 20-50 ℃, the boiler thermal efficiency can be increased by 1-3%; (2) latent heat of vaporization: realized by the phase change of water vapor condensation into water, the boiler thermal efficiency can be increased by 3-5% after testing Both of them can improve the boiler thermal efficiency by 3-8% The thermal efficiency of gas-fired boiler has reached 90% If the boiler body is reformed to improve the thermal efficiency, it will not be worth the loss By using the heat recovery system of flue gas condensation, the heat efficiency of the boiler can be increased by 3-8% without affecting the heat efficiency of the boiler itself, which will be an energy-saving way with low investment and large income 2.3 gas heating energy saving technology III: the hydraulic balance of heating system and the energy consumption of heating system are not only determined by the heat source, but also related to the whole pipe network system In the heating system, there is a widespread problem of hydraulic imbalance, which results in the uneven heat and cold of the system For users close to the heat source, the indoor temperature is higher, while for users far away, the indoor temperature is lower In order to ensure the indoor temperature of remote users, it is necessary to improve the temperature of water supply network and increase the circulating water volume, which not only makes it difficult to ensure the heating quality, but also causes huge waste Through the actual test, the unit flow of the near end users is often several times that of the far end users In order to make the far end users reach 16 ℃, the room temperature of the near end users has exceeded 20 ℃, and even opening the window causes energy waste Therefore, through practice, the hydraulic balance debugging can save about 10% energy 2.4 gas heating energy saving technology 4: gas boiler room heating centralized control system: the gas boiler room heating centralized control system developed by JinFang heating and ventilation company is a computer heating control system designed with a new concept based on years of operation and management experience of heating enterprises and fuzzy control theory Through the calculation of various parameters of each boiler and the parameters of the whole heating system, the theoretical boiler load is obtained, and the actual load of the boiler and which boiler to start are adjusted according to it Through the centralized control of the boiler by the microcomputer, each boiler in the boiler room can be operated circularly, and each boiler can be switched automatically and regularly according to the load rate of the system On the basis of ensuring energy saving, the service life of the boiler is extended The centralized control system can not only control the boiler, but also control the system equipment such as the climate compensator, so as to control the whole system 2.5 energy saving technology of gas heating 5: time sharing and zoning control: through the time sharing and zoning control of the indoor temperature of schools and office areas, the purpose of heating on demand can be achieved, which can save energy very well For the district heating area, if there are office buildings and school buildings, the heating should be carried out according to the needs to reduce waste We have achieved good energy-saving effect by using it in Badachu middle school 3 Application example of energy saving system of gas heating in Beijing The energy saving system of gas heating boiler room has been applied in many projects in Beijing Now, I will introduce several typical projects to you 3.1 the heating system of yanjingsi boiler house in Chaoyang District, Beijing Chaoyang heating company started to reform the coal-fired boiler house in yanjingsi in June 2003 The heating area of the boiler room is 27900 square meters, with more than 560 heating households It used to be two 2.8MW coal-fired hot water boilers After retrofitting, the boiler is one 0.7wm and one 1.4wm gas-fired hot water boiler In the reconstruction, the secondary pump system with water mixer is used in the water system, the condensation heat recovery device is set in the smoke system, and the climate compensator is used in the intelligent automatic control, so as to realize the real-time adjustment of the heating capacity of the user's heating system according to the outdoor temperature change, so as to achieve the purpose of energy saving At the same time, the return water temperature of the boiler is not lower than 55 ℃, which solves the problem of boiler condensate, reduces boiler corrosion and prolongs the service life of the boiler Since the system was put into operation on November 7, 2003, it is safe, stable, with strong anti-interference ability, accurate measurement data, sensitive signal transmission, accurate regulation and no adverse effect on the system Without manual operation, it is all automatic control, and the labor intensity of the stoker is greatly reduced All adjustments are completed by the climate compensator "We have a 24-hour Engineer in the boiler room," said the stoker with a smile Once the system is put into operation, obvious energy-saving effect is achieved The following table shows the actual consumption of gas meter: Name: initial cold period, severe cold period, November 23, November 24, November 25, December 9, December 10, December 11 Daily gas consumption (m3 / day) 1704 1824 1776 1912 1901 1877 average daily gas consumption (m3 / day) 1768 1897 estimated total winter gas consumption (M3) 1768 × 30 ＋ 1897 × 60 ＋ 1768 × 45 = 246420 indicates that the heating period of the whole winter in 2004 is 136 days from November 7, 2003 to March 21, 2004, with 39 days in the initial cold period, 62 days in the severe cold period and 35 days in the final cold period In order to test the energy-saving effect more accurately and provide reference for future energy-saving transformation and professional counterparts We specially invite Beijing energy conservation and environmental protection service center with testing qualification to conduct energy conservation test The system was tested by Beijing energy conservation and environmental protection service center from December 11 to 14, 2003 The energy-saving system shall be put into operation for * 24 hours by using the comparative test method After the energy-saving system is removed and stabilized for one day, the energy-saving system shall not be used for 24 hours for test The energy saving rate reached 10.89% Total winter consumption of yanjingsi boiler house