Steam boiler performance characteristics: water tube chain grate coal fired steam boiler Features: 1. Boilers faster horizontal fire tube boiler, refrigerant natural circulation. A boiler drum boiler heat exchange system, the left and right water wall header and composition, the main heating surface of furnace wall, part of the boiler tubes and boiler tubes in the convection tubes. This product consists of five main part of the boiler, flue dust, piping system. The first four members manufactured in a factory, can be transported to the installation site for assembly, shorten the installation period, to ensure the quality of the product installed. 2. Advanced Design Performance: main heating surface of the boiler 20 # low-pressure boiler seamless steel, special steel boiler tube boiler. Left and right header made seamless pipe. three. Boiler refractory concrete arch was destroyed. After another bow low and long, and it will burn well. Flue and side wall are made of bricks. Front and rear wall of the boiler use ordinary bricks made. 4. Exhaust flow and reasonable distribution of large combustion chamber, applicability coal. For a variety of bituminous coal or anthracite, mixed coal. very hot. High temperature flue gas enters the first settling chamber, and then into the flue wings from both sides, before re-entering the smoke box, smoke dust good effect. Simple water cycle, the compression pieces reasonable structure, safe operation of the premise of ensuring water quality. 6. The combustion apparatus is a fast loading grate, combustion equipment manufactured in a factory and installed, transported to the construction site may be mounted directly on the foundation. The present invention has a reasonable structure, compact, low steel consumption, performance, weight, size and structure of the boiler with the same capacity has significantly improved compared to the advantage of domestic products. Boiler work process: a substantially uniform coal particles by an automatic stoker coal thrown into the hopper, preheated before entering the arch in the case of rotating chain grate. Were burned in the incineration zone, fell into the slag pool. The high temperature flue gas produced by combustion of the furnace arch port into the furnace from a lower portion of the rear flue two wings, the wings and then heat the flue, through the forward flow before the packets enter the convection heat transfer tube bundle, then the tail tube boiler and dust entering the economizer section, and discharged to the atmosphere through a chimney to the induced fan. Boiler feed water is supplied by a boiler feed pump, demineralized water supplied by the economizer, and then enters the drum, and then enter the downcomer around header. Endothermic steam is generated by vaporizing water wall on both sides, into the steam within the steam separator drum, after separation, the main steam valve into the process heat required.
The heat loss of exhaust smoke is the largest of all kinds of heat loss in boiler. Generally, the heat loss of exhaust smoke is 6% of the heat fed into the furnace, and the heat loss of exhaust gas increases 0.5% when the temperature of exhaust gas increases by 12 ℃ and 15 ℃. So the exhaust temperature is one of the most important indicators of boiler operation. The following are several possible causes of increased flue gas temperature in the furnace: (1) slagging and ash accumulation on the heated surface. No matter it is the slag accumulation in the water-cooled wall of the furnace, or the ash deposition in the superheater, convection tube bundle, economizer and preheater, the thermal resistance of the flue gas measurement will increase, the cooling effect of the flue gas will become worse due to the deterioration of the heat transfer, and the exhaust temperature will rise. (2) excess air coefficient Big. Under normal conditions, the exhaust temperature increases with the increase of excess air coefficient at furnace outlet. After the increase of excess air coefficient, although the amount of smoke increased, the rate of smoke increased, and the convection heat increased, the increase of heat transfer was not as much as that of the increase of flue gas. It can be understood that after the increase of smoke speed, the flue gas leaves the heating surface without time to transfer heat to the working fluid. (3) the air leakage coefficient is too large. The flue gas leakage in the furnace and rear shaft of a negative pressure boiler is inevitable and the leakage coefficient allowed by a certain heating surface is specified. When the air leakage coefficient increases, the effect on the exhaust temperature is similar to that of the superheated air coefficient. And the air leaks away. The closer the furnace is, the greater the influence on the rise in exhaust temperature. (4) Water supply temperature. When the steam turbine load is too low or the high pressure heater is out of line, the feed water temperature of the boiler will be lowered. Generally speaking, if the fuel quantity is kept constant, the heat transfer temperature difference of the economizer decreases and the heat absorption of the economizer decreases when the feed water temperature is increased, which makes the exhaust temperature increase. (5) moisture in the fuel. The increase of moisture in the fuel increases the amount of smoke, thus increasing the exhaust temperature. (6) Boiler load. Although the boiler load increases proportionally, the amount of smoke, the amount of steam, the amount of water supplied, and the volume of air increase proportionally, however, the flue gas temperature at the furnace outlet increases proportionally. Increase, so that the exhaust temperature increased. After increasing the load, the outlet temperature of the furnace increases, the heat transfer temperature difference of the convection heating surface increases and the heat absorption increases. Therefore, the more the convection heating surface is, the less the influence of the boiler load on the exhaust gas temperature is. (7) fuel varieties. When the low calorific value gas is fired, the radiative heat transfer in the furnace decreases due to the decrease of furnace temperature, and the non-combustible components in low calorific value gas, mainly N _ 2, CO _ 2 and H _ 2O, increase the amount of flue gas, so the exhaust temperature increases. Although the excess air coefficient of furnace outlet is lower than that of coal burning, the ash content in the fuel oil is very low after the pulverized coal furnace is changed to burn oil, although the excess air coefficient at the furnace outlet is lower when burning oil. There is no larger ash particle in flue gas, and there is no cleaning effect of larger ash particle on the heating surface, and the convection heating surface is polluted more seriously. Therefore, combustion is not good, often smoke-emitting boiler smoke temperature rise. When there is a steel ball dust removal device at the tail, the exhaust temperature is slightly lower than that of burning coal because the tail is cleaner. (8) the operation mode of pulverizing system. For a closed pulverizing system with a silo, when the pulverizing system is in operation, as a part of the water in the fuel enters the furnace, the furnace temperature decreases and the flue gas increases, and the cold air leaking into the pulverizing system enters the furnace as a primary air during the operation of the pulverizing system. Reduction of air flow through air preheater To raise the exhaust temperature. On the contrary, when the pulverizing system is shut down, the exhaust temperature decreases.
How many calories Horizontal one ton water tube chain grate coal fired steam boiler needs? 1 ton steam boiler, require 600,000 calories, biomass is the most economical fuel. 1 t of steam boilers, 600,000 calories needed, is converted into fuels: diesel 58kg / hour, i.e. cost of diesel and 466 / hour; biomass particles 150kg / hour, the cost of 165 / hour. 697 electrical degrees / hour, i.e. cost of electricity 697 / hour; gas 75m3 / hour, i.e. cost of natural gas 375 / hour; 120kg of coal / hour, i.e. cost of coal is about $ 120. As can be seen from the above, coal and biomass particles are the most economical. Wherein the combustion of coal is difficult to control, and the actual consumption costs considerably biomass particles. However, polluting coal boiler is very large, and the biomass boiler is both economical, and environmentally friendly. Accordingly, we can see that biomass pellet boiler is the best future direction of development of the industry boiler, the boiler will also become the industry mainstream.
Environmental situation is not optimistic that China has issued a number of environmental policy, the full range of safeguards ecological environment. Provinces are also actively to improve environmental protection, recently, Ningxia Hui Autonomous Region winter heating boiler proposed implementation. details as follows.
"Clean heating embodiment of Ningxia Hui Autonomous Region (2018 Year - 2021)," recently released, "plan" put forward, Ningxia heating the status quo, to develop clean heating, the use of clean energy alternative to coal and dispersed living coal, reducing coal consumption and soot emissions, improve environmental quality in urban and rural atmosphere.
By the end of 2017, Ningxia urban and rural housing construction for heating a total area of 380 million square meters, of which the city building heating area of about 240 million square meters, rural buildings for heating an area of about 140 million square meters. Clean heating total area of about 180 million square meters, accounting for about 47% of the region's total heating area. Among them, prefecture-level city clean heating an area of about 120 million square meters, clean heating rate of about 75%; counties (cities, districts) Clean heating an area of about 50 million square meters, clean heating rate of about 62%; rural clean heating area of about 14.72 million square, clean heating rate of about 10%.
After the "plan" put forward, Ningxia, according to the "central heating mainly to the substitution of gas for coal as the first, supplemented by electricity instead of coal," the idea, according to local conditions, scientific planning, coordination implementation. City, county (district) the main city clean coal-fired co-generation, large-scale energy saving boiler central heating heat source as the basis for strengthening efforts to shut down within a small range of central heating boilers of coal. Promote cogeneration units and ultra-low emissions transformation of large boilers, improving the environmental standards.
In urban and rural interface and rural areas, in accordance with the principles of the easier issues first, and start cleaning centralized heating schools, kindergartens, hospitals and other public buildings start to play an exemplary role. The conditions of the area to promote gas boiler; encourage nearby collected plant biomass feedstock, biomass briquette forming process instead of bulk coal; encourage livestock waste, straw and other raw material for the biogas fermentation and purified, for clean heating; actively promote the development of geothermal resources as a centralized or decentralized heating heat source; support for residents to install solar hot water, electric heating equipment, such as housing, agriculture greenhouses, farms; do not have clean heating conditions actively implement clean coal alternative bulk coal.
"Plan" clearly, Ningxia will accelerate cogeneration, waste heat utilization, the cell set into a piece of construction heating boilers, focusing on the completion of the Western Xia thermoelectric (two) central heating, in Nanjing Tianyuan thermoelectric, Helan back pressure Heating Unit central heating and other projects, the completion of thermoelectric Zhongwei, Wuzhong thermoelectric, thermoelectric Dawukou LIUPANSHAN thermoelectric renovation project, to further expand the central heating area. City, county (district) heating should vigorously promote the "coal to gas," "coal to electricity", according to local conditions the development of renewable energy for heating, a pair of old, energy-saving secondary pipe network, heating network system to enhance efficiency.
Ningxia will be fully phased out small coal-fired boilers, coal-fired boiler to deepen the comprehensive compliance management, municipalities, county (district) urban area out of 20 tons of steam / hour coal-fired boilers. Yinchuan City urban area to total phase-out project cogeneration district heating pipe network covering all coal-fired heating boilers in the region. It does not have the "coal to gas," "coal to electricity" conditions in rural areas, to achieve clean coal production and warehouse distribution center full coverage, full implementation of clean coal alternative bulk coal.
Ningxia Hui Autonomous Region in the 2018-2021 four-year, with the full complement of winter heating boiler, will replace all cleaner energy boiler coal-fired boiler, to protect people's health.