Several cases of biomass steam generator exception handling

When the biomass steam generator abnormal failure, affecting the normal operation, the following analysis and processing.

First, the feeder side of the feed

B side of the feeder can not run because of electrical reasons, leaving only A side feeder single side fabric, open the A side of the furnace wall manhole door, only to see the fuel stuffed, do not see the fire. Open the B side of the furnace wall manhole door, see the stove with 1m wide no material corridor. This caused the A side of the fuel once the wind does not move. B side because there is no fuel to form a large number of holes in the area, the primary air through the furnace without the furnace into the hole, reducing the temperature of the furnace furnace a very uneven distribution of the wind, the normal boiler combustion can not be established.

Take the opening 1A, 2A ignition wind, with the ignition wind to blow the fuel to the B side of the move, that is to use the wind on the side of the A side of the fuel blowing to the B side, as far as possible to the fuel blowing to the furnace, as far as possible so that the fuel covered Grate, the formation of a whole bed fire, the structure of a balanced flame temperature zone, improve the flame in the grate full degree. With this method, 1 hour after opening the door inspection, the fuel distribution is roughly uniform, B side of the furnace above the fuel has been burning, the combustion conditions greatly improved, received a good effect, the load from 10MV to 25MV The

It is recommended to burn the biomass steam generator of the yellow stalk. At the ends of the A and B feeder, the wind source can be installed in the ignition duct, and the distribution of the fuel can be changed by adjusting the pressure and angle of the sowing wind , So that the fuel does not accumulate in the flexible tube, so that high-end regional fuel will not be too thick, conducive to a wind through.

Second, the pre-dust collector ash pipe serious blockage

(1) into the furnace fuel ash are generally more than 30%, the amount of ash generated by combustion too much.

(2) burn adjustment is unreasonable, a wind is too large, the flame is too long, penetrating speed, secondary air use is too small (40% of the back wall, 20% of the front wall), can not suppress the flame. In the secondary air area can not form a strong reflux agitation, can not form flue gas combustible continue to burn, the temperature field shift, after the water wall and superheater heat exchange, the smoke in a large number of solid particles of the speed of rapid decay; After four heaters after the heat into a low temperature ash. Smoke in the smoke at high speed, was brought into the pre-dust collector. The erroneous operation of the adjustment resulted in incomplete combustion, allowing the machine to carry the ash to the tail, resulting in a much greater amount of ash than the pre-divider design capability.

(3) pipe design is too small, the diameter of 108mm pipe ash off too much force, Roots blower air pressure is low, 0.4mpa can not meet the requirements of the amount of ash.

solution. (1) to adjust the combustion to 20MW load as an example: a wind high-end baffle opening of 50%, mid-range baffle opening of 70%, 30% of the low-end baffle, so that combustion in the secondary air outlet. (2) secondary air: the front wall baffle opening is 40%, rear wall baffle opening of 60%, as far as possible so that coal is built in efficient areas. (3) to maintain the boiler furnace pressure -50pa, the combustion of high temperature area control in the secondary outlet below, to maintain the burning speed, to ensure the degree of combustion, combustion speed to carry the amount of ash to reduce.

Suggested equipment transformation. (1) replace the large diameter of the ash pipe, replace the high-power Roots blower; (2) pre-duster to install the lower gray mechanical screw, to reduce the amount of ash up.

Three, a pole of the superheater vibration

There have been a number of biomass power plants in China, with varying degrees of first-order superheater vibrations, respectively, in high, low load, soot. Grate vibration, the initial ignition time was identified as resonance phenomenon.

(1) steam drum in the saturated steam penetration rate of 1m / s, from the drum out of the saturated steam through a 168 connected pipe (speed of 8m / s), into a superheater (speed 20m / s). As the steam flow cross section changes, the resistance increases instantaneously, the steam flow rate suddenly becomes larger, it may produce steam shock, in the thermal cycle is likely to form a plug.

(2) saturated steam through the superheater into superheated steam, is a very intense heat exchange process. Flue gas flow rate and temperature, in the steam generator load changes, fouling, coking and other conditions change, will have a huge impact in the flue gas, and thus the formation of the superheater tube steam pulsating impact.

(3) the same load of the pulverized coal furnace, fluidized bed furnace generally does not produce superheater vibration, because from the drum to a superheater has eight connecting pipe. They enter the uniform, will not produce too much pressure, the steam flow rate will not be drastic.

Suggest. (1) in the vibration of the superheater installed anti-vibration plate. (2) combustion adjustment should pay attention to the vibration of the superheater on both sides of the smoke can not be greater than 30 degrees, can not cause excessive wall temperature difference. (3) to change the design, in the drum outlet and the superheater inlet tank to install the distribution pipe to balance the steam flow rate.

Biomass steam generator is a possible thermal system of various problems, to be comprehensive and objective to deal with the occurrence of abnormal failures, to ensure safe and economic operation.