What energy-saving measures are there in the heating boiler room?

(1) Energy saving potential of heating boiler room. Under normal technical conditions, a 0.7 MW boiler can provide 1 1,000 square meters of heating for general residential buildings; For industrial boilers, steam boilers with a capacity of 2 ~ 40 tons/hour or hot water boilers with a capacity of 1.4 ~ 28mw, the thermal efficiency is generally 72% ~ 80%; The thermal efficiency of boilers with a capacity of less than or equal to 4 tons/hour is the lower limit, and the thermal efficiency of boilers with a capacity of more than 6 tons/hour is above 75%. The practice of boiler operation proves that under normal technical conditions, some boilers can run stably for a long time with thermal efficiency above 75%, the utilization rate of boiler equipment can be increased by 40% compared with the national average level, and the thermal efficiency can be increased by 13%. Their comprehensive benefits are not only saving fuel, electricity, transportation and manpower, but also reducing environmental pollution and saving initial investment (including equipment investment, construction investment, land area, etc.). ). In addition to the above indicators, boiler room energy saving also includes boiler auxiliary power saving, reducing the reserve coefficient of boiler equipment and auxiliary equipment, and rational utilization of investment. Visible, boiler room design in the case of reasonable boiler capacity configuration, the energy saving potential of heating boiler room is huge.

The so-called "1 steam ton for heating several building areas" is a popular saying in current heating technology. Strictly speaking, there are two situations when the boiler capacity is 1 steam ton (the hot water boiler is 0.7 MW) to provide heat for several building areas: one is the heat preservation and system leakage rate of the heating network and heating system of the building complex. The thermal and hydraulic conditions are basically normal, which is used as an index to measure the operation status of boiler room units. The second is the comprehensive influence of boiler unit and the above technical parameters on heating network and heating system under abnormal working conditions. The latter situation, such as serious damage of insulation layer, excessive leakage rate or serious imbalance of thermal and hydraulic conditions, is easy to be exposed, and users generally pay more attention to it and try to solve it.

(2) The important position of the heating boiler room. At present, the average steam ton in China is only 6000 square meters, which is mainly due to many unreasonable factors in practical engineering. The key problem is that the heat source of heating system-boiler unit has not reached the normal technical level.

As a heat source project, boiler room is a systematic project consisting of four main links: product design and manufacturing quality of boilers and their auxiliaries, process design, installation and construction of boiler room, and management and operation of boiler room. If there is a problem in one link, it will affect the overall situation and cause the running state of boiler equipment to deteriorate.

Energy-saving technology of boiler room

Energy-saving operation of boiler room involves the selection of boiler and boiler auxiliary equipment, rational design of boiler room, installation quality of boiler room, operation management of boiler room and actual operation of stoker.

The biggest feature of boiler is that one boiler corresponds to one coal type. When selecting the type of boiler, not only the structural form, capacity and quantity of the boiler should be selected according to the required heat load, heat load continuation diagram and working medium, but more importantly, the combustion equipment should be selected according to the fuel types supplied by local users, which is the premise of boiler energy saving. Secondly, according to the investment, construction progress, land area and other factors, choose assembled boiler or bulk boiler. Therefore, when selecting the boiler type, we must carefully examine the operation examples of the boiler and fully grasp the local fuel characteristics, so as to optimize the selected boiler type, otherwise it will not only waste money, but also waste fuel.

As far as the selection of boiler auxiliary equipment in heating boiler room is concerned, China has not yet formulated a clear capacity index of auxiliary equipment. The investigation shows that for the boiler room with the same capacity, the maximum difference of electric power of boiler auxiliaries such as blower and induced draft fan can reach more than one time. It is suggested to select the type according to calculation, and the calculation formula can be consulted in various boiler room design manuals and related works. The selection of auxiliary machines of boiler equipment has a great influence on the energy-saving effect. Only when the equipment selection is reasonable can the best economic benefits be achieved.

The quality of boiler installation and construction is not only related to whether the boiler can run safely and reliably, but also to the long-term operation status and energy-saving effect of the boiler, especially for bulk boilers. Boiler installation is the continuation of boiler manufacturing process. The running state of grate, the sealing performance of flue and air duct, the sealing performance between downwind chambers of grate and the masonry quality of furnace wall have great influence on whether the boiler can run at full load and save energy and reduce consumption. The following focuses on the operation and management of the boiler room.

Boiler operation management is aimed at heating enterprises or management departments. Generally, most boiler rooms with a single capacity equal to or greater than 10 steam tons are equipped with relatively complete thermal monitoring instruments, even with microcomputer circulation detection and display, and equipped with relatively complete technical management departments, which greatly improves the management level, but there are still the following problems worthy of attention:

(1) Equipped with full-time firefighters. The fireman's job is a highly technical job, which has a direct impact on the economy of boiler operation. For the heating company, it is the first-line mechanic. However, at present, there are many temporary firefighters, which is an important reason why the boiler can't run at full load in the economic state. Because the boiler operation should adopt different operation modes according to the characteristics of various coals, even if the same variety of coals is subjected to the change of base moisture, the thickness and advancing speed of the coal seam will also change accordingly, and with the change of outdoor temperature, it is necessary to adjust the boiler combustion load, which is impossible for the system to be rigid.

(2) Improve the testing system. In some places, the index of coal saving is the carbon content of slag, which ignores the heat loss of flue gas. In order to reach the qualified carbon content of slag, the stoker excessively increases the residence time of coal in the furnace and the slag area, which leads to the increase of excess air coefficient. Excessive air coefficient in the furnace is too large, the average temperature of the boiler hearth decreases, the excessive air coefficient of smoke exhaust is large, and the resistance of dust collector increases, which reduces the required air volume for combustion and greatly reduces the thermal efficiency of the boiler. The heat loss of smoke exhaust can't be observed with naked eyes, so it is most easily ignored.

(3) Establish a reasonable operation system. The unreasonable operation system of boiler room is another important reason for the low thermal efficiency of boiler. For example, the running time of two 20t/h chain hot water boiler rooms in a heating company is as follows:

1: 00 ~ 8: 00 (running for 7 hours)

9: 35 ~ 12: 30 (running for 2 hours and 55 minutes)

12: 00 ~ 17: 50 (running for 5 hours and 50 minutes)

18: 30 ~ 22: 30 (running for 4 hours)

It runs for nearly 20 hours all day and is divided into four times. According to the boiler, it takes at least 2 hours from the fire suppression state to the basically stable thermal state, as shown in the following table. In the above operation system, the unstable working condition with low efficiency accounts for 42% of the total operation time. If the above operation time is changed to 9.5 hours twice a day, the unstable working condition accounts for 2 1% of the total operation time, and the boiler load and thermal efficiency will be greatly improved.

Thermal condition of boiler after pressure fire start-up

Time10:15 ~1151:15 ~12:15/.

(4) Prevent the operation mode of "big horse-drawn cart". Running the boiler under "big horse-drawn trolley", that is, running at low load rate, is another important reason for the boiler to waste energy. Only when the boiler operates under the rated load of 70% ~ 1 10% can it be in an economic working state. As can be seen from the following table, when the load rate is 76% under stable working conditions, the highest efficiency of the boiler is 76.6%, and the efficiency of the boiler under continuous low load is 66.09%, which is higher than that under long-term shutdown. When the load rate is 8 1%, the operating efficiency of the boiler under unstable working conditions is 63.08%.

Test results of the same boiler under different operation modes

Total running time/hour Boiler efficiency (%) Load rate (%) Remarks Continuous running 7266.0953 See note ① Intermittent running 37.563.05438+0 See note ② Steady working condition is negative.

See note ③7.6776. 676 for the load rate operation. Note: ① It starts at 2 o'clock on March 18, and the low load rate runs continuously until 8 o'clock on March 2 1 8.

(2) Intermittent operation of the boiler/shutdown in kloc-0/2 hours 12 hours, and shutdown from 8: 00 on March 2/kloc-0 to 6: 00 on March 24.

(3) During the above-mentioned intermittent operation, that is, from 8: 00 on March 22nd to 6: 00 on March 23rd, the boiler works for 7.67 hours under a certain stable working condition.

In a word, the four main links in boiler room system engineering are closely related. If a main factor in a certain link is out of control, it will affect the economic operation of the boiler and reduce the heating area per ton of steam capacity.