Cement plant combustion system upgrade to save coal consumption
Date：2019-08-28 13:04 Source：cementepcViews:
In cement production, coal consumption accounts for more than half of the total clinker production cost.How to reduce coal consumption of cement plant to talk about his view below.The coal consumption of cement plant is mainly concentrated in the clinker burning part, and the heat generated by coal combustion is mainly divided into three parts.
1.The combustion of pulverized coal produces heat
(1) for the firing of clinker, it is basically a fixed value after the composition and quality of raw material are determined;
(2) heat taken away by exhaust gas, mainly heat taken away by exhaust gas discharged by high-temperature kiln tail fan and heat taken away by kiln head exhaust fan;
(3) mainly heat dissipation from the system surface.Therefore, to reduce coal consumption, we should start from the second and third aspects.
To reduce waste gas and take away heat, it is necessary to reduce waste gas quantity, reduce waste gas temperature, and further utilize waste heat of kiln system by using low-temperature waste heat power generation technology.
2. Reduce emissions
To reduce the amount of waste gas, the air surplus coefficient of the whole system should be controlled to reduce air leakage in the system.Theoretically, for every 1% increase in excess air, the standard coal consumption of tons of clinker increases by about LKG/t·cl.Therefore, strict control of excess air volume, maintain the preheater export O2 between 2% ~ 4%.The total ventilation volume of the system is reasonable, which can keep the outlet temperature of the preheater at a low level and avoid unnecessary waste of heat.On the basis of ensuring the air used in combustion, air leakage in the system should be minimized, which will greatly increase the coal consumption.
Air leakage in the system generally occurs in the following parts:
(1) air leakage at the seal of kiln head and end has a great influence on coal consumption.
(2) air leakage of manhole door, observation hole and flap valve at all levels of the preheater, the air leakage volume of this part is also very large, but if this part is properly managed, it can be completely avoided.
(3) to reduce the temperature of waste gas, it is necessary to recycle the maximum amount of heat from the reasonable distribution of air used in kiln and coal used.Rational use of primary air volume, no matter the kiln head, kiln tail coal injection pipe used by the primary air is cold air, with the increase of primary air volume, coal consumption will increase.
3. Mechanical equipment
Large kiln door cover technology and the third generation of inflatable grate cooler are commonly used in large kilns.These two items play an important role in recovering heat and reducing the temperature of exhaust gas from the kiln head.The third generation of grate cooler with gas-filled beams is a more even distribution of air volume on the grate plate, which can be operated by thick material layer to reduce the short circuit of wind, play the role of quenching the clinker, and maximize the recovery of heat in the high temperature area.
Surface heat dissipation of rotary kiln system is also an important aspect of coal consumption of rotary kiln.And heat are mainly concentrated on the rotary kiln shell, account for about 60% of the total heat release, thus reduce the surface temperature of rotary kiln becomes the key to reduce system heat dissipation, to reduce the surface of the kiln body heat is mainly choose suitable refractory materials, in the calcining zone is characterized by the reasonable thickness of kiln, the reason is that the coefficient of thermal conductivity of kiln less than the coefficient of thermal conductivity of the basic turn.Especially in the old line maintenance, construction team pursuit of construction speed, no use of thermal insulation materials, system surface temperature is higher, more heat dissipation, resulting in increased coal consumption.
The main ways to reduce coal consumption at present are the adjustment of reasonable process system, the completion rate of equipment, the recovery and reuse of waste gas in kiln system, and the rational use of refractory materials.Jiangsu LVSSN more products, about the Raymond mill can consult our online customer service