Abstract: The analysis and introduces gasifiers operation, run frequently encountered cold, hot running and partial run conditions such as abnormal characteristics, causes and adjustment method. Also pointed out that gas station is a system composed of many sub-systems are often reflected in a branch system failure is caused by another sub-systems, the need analysis to find out the source of the fault system, which effectively troubleshooting, operation Gasificaton personnel only combines integrated throughout the system, the correct analysis of its origin and formation mechanism of failure to symptomatic treatment, so as to effectively ensure the normal production furnace.

Keywords: gasifiers, coal gasifiers, coal gasifications; cold running; heating operation; partial operation; characteristics; reasons; adjustment
1 Introduction
Coal gasification and rational utilization of coal conversion is one effective way, in line with China's development of clean coal technology, energy diversification strategy, China has both the current and long-term significance. In recent years, pressurized moving bed and entrained bed, fluidized bed ash agglomeration and airflow bed gasification technology have been rapid development, at present, as small and medium scale atmospheric fixed-bed gasification fuel gas main supply unit scale of production, the cost of investment, construction period, which qualify for the majority of metallurgical, chemical, building materials and machinery industries such as gas demand is widely used.
Press the gasifiers production process characteristics distinguish its furnace solid materials are generally divided into five, namely dry layer, carbonization layer, the oxide layer, reducing layers and layers of ash. Wherein the oxidizing and anoxic layers has been referred to as the gasification reaction layer, the oxide layer of carbon is oxidized by oxygen in the gasification agent into carbon dioxide and carbon monoxide, and release a lot of heat, gas heat produced by the chemical reaction heat required for this to maintain the temperature of the oxide layer is generally maintained at 1100 ~ 1250 ℃; reducing layer is a region of combustible gases generated key, carbon dioxide and hot work, an endothermic chemical reaction, producing combustible carbon monoxide; steam and hot endothermic carbon chemical reaction to produce carbon monoxide and hydrogen flammable, and absorb a large amount of heat. Furnace properly maintained at all levels, especially the oxidized and anoxic layers of temperature, altitude and balanced degree of maintenance is essential, otherwise there may be cold run, hot run or partial operation of such abnormal furnace conditions, thus affecting the Gasifications of normal production.
2 furnace heat run
2.1 Thermal characteristics and reasons for running
Gasifiers operation means the occurrence of thermal layer temperature is too high charge state, where usually refers to the fire layer material layer and surface layer temperature is too high-temperature phenomena. In this case, if you open the roof fire detection hole, the furnace is glowing, emerge naturally ignited gas, slag stratification big, temperatures up to 1300 degrees, the temperature is high, if the probe is easy to solder blown, roof exterior will appear higher temperatures, the furnace will burn off spreading device such as coal, gas laboratory analysis, with relatively high carbon dioxide, carbon monoxide is relatively low. Thermal reasons for running ash layer is too high, the total coal is too low, the oxide layer (fire layer) on the move, reducing layer, dry layer distillation barely, and became a big fire stove.
When the fire layer temperature is too high, it will produce just under the layer of ash in the ash fire layer slagging phenomenon, then the gas temperature does not reflect the high temperature fire layer, only by measuring the flux and According ash discharged can be reflected, so the fire bed temperature is too high, the level of the normal distribution is imperceptible. Another hot running phenomenon, the entire hierarchy upwards, and thin coal seams, then you show the material layer surface temperature is high, then the furnace the temperature is high. The third heat run, the performance of most of the material layer burn, the fire layer exposed, a gas furnace temperature rises rapidly. Thermal operation result, the former is caused by deterioration due to slagging, affect the next stage of the production, the latter two are immediately reflected in the gas quality (heating value) decrease.
2.2 Heat treatment furnace conditions run
Thermal operation is characterized as a "hot" character, the process of heating operation to symptomatic after two different ways. For the former fire layer high thermal operation, should raise the saturation temperature, increasing the amount of water vapor in the gasification agent, accelerate the decomposition reaction of water vapor, so that the fire layer temperature down; For the latter two material layer surface temperature is too high should speed up the ash, increasing the amount of coal added to improve the material thickness.
Since the oxide layer slagging, often appear partial burning phenomenon, because the site of coal slagging off not down, no slagging bit whereabouts relatively smooth, if not promptly treated, over time, to form a smooth part of the oxide layer Huo , slagging parts flow is not smooth, the oxide layer is not busy fire until the fire. Note that for this situation, to increase the saturation temperature (steam), lower temperature oxide layer, with a thick 30mm drill rod broken slag, ash tray while turning, squeezing small ash of the furnace. If the furnace ash too big, with thick solder fight is not broken, it must be shutdown process. Otherwise it will damage the grate and other equipment, resulting in large losses.
3 furnace cold running
3.1 cold running characteristics and causes
Cold operation means the occurrence of furnace material layer is cold, this phenomenon and hot running condition also different place, sometimes running hot heat cold outside (refer to the fire layer temperature is high, while the surface temperature is not high ), the material layer is sometimes high temperature, and cold temperature operation is the lower material layer. Cold running gas furnace, the furnace from the fire detection observed black hole is slightly red, drill exploration oxide layer simply undetectable or insignificant. Carbon monoxide and hydrogen gas in the test concentrations are low, and high moisture content.
Saturation produce cold temperature operation causes excessive due to the saturation vapor into the bottom to the oxidation layer, the oxide layer the temperature drop, and the amount of carbon dioxide is low, not enough to restore the temperature of the reaction, water vapor can not be decomposed in the oxide layer, much less and carbon synthesis reaction. To the high content of carbon dioxide gas, carbon monoxide content is low, moisture content and more. Because low temperature oxide layer, not a lot of coal gasification, gasification of char no more than about 20%, some up to 30% waste is amazing. In the cold runs, the first oxide layer temperature is too low, reflecting not severe oxidation, reduction reaction also will then be weakened, at this time is often at the seams thicker, but also absorb a lot of heat, leading to the gas temperature furnace decline. Word cooling operation is the final analysis, is not to achieve complete gasification, so the result is that the gas cooling operation is the quality (calorific value) decrease. Run cold will cause some serious fire zone layer temperature gradually decreased, and finally reach some areas completely unable to play oxidation layer flame fire until some results.
3.2 runs cold treatment furnace conditions
Mostly in the cold air flow running down, the saturation temperature regulation is not kept pace stoker continues unabated, particularly in the high moisture content of the coal, will gradually transferred to the cold operating state. To overcome the cold-running state, the first is to reduce the saturation temperature, while reducing material layer, so that the fire layer temperature rises gradually, and finally return to normal state.
4 furnace partial run
4.1 Partial running characteristics and causes
Partial run customarily called partial furnace, by definition, the "partial" refers to all areas of the material layer temperature differences are the following phenomenon: some half cold, half hot; some part of the cold region, part of the normal state; some part of the district heating, part of the region the normal state; plenty hot center, edge cold; plenty of edge heat, central cold; plenty of hot center and periphery, the intermediate ring with cold; plenty of cold center and periphery, the intermediate ring with thermal. Most of bias arises from the following types of furnace reasons:
(1) Since the ash body caused by congenital defects, often in the big gray knife before the fire layer on the move, big gray knife drop occurs after the fire floor, the situation is severe, the side causing the surface sparkle, causing the other side of the fire layer down bottom.
(2) of the air flow and increase the performance of the coal body suited, in a small flow, the temperature tends to lower edge, and the center temperature is high. In the large flow is often caused by edge temperature is high.
(3) Since the particle size can also cause partial coal furnaces, coal when using smaller particles, the center stoker more, the center temperature is low, the edge temperature. When the coal particle size is too large, the resulting center of high temperature, low temperature edges.
(4) Since the slag and clinker, affecting up that part of the material layer, resulting in the furnace side.
(5) Since the slag properly, high-speed large ash content of the slag, resulting in a large gray area after local fire knife off the bottom layer and partial furnaces.
4.2 Partial operation processing furnace conditions
To solve partial problems running remedy should be avoided prolonged high flow production or prolonged low flow production, ash body issues should be distributed in the four weeks to adjust the length and width of a small gray knife to adjust the uniformity of its ash For stoker coal board carve agency blocks according to different degrees and common traffic make the appropriate changes, for stoker material layer should be based on the temperature distribution of each region were determined to give coaling or without coal, more or less coal stokers, for the ash to absolutely prevent faster and shoved out the ash should actively promote small loop method.
Meanwhile, partial furnace manual operation when they depend on, that should play more high surface temperature brazing, the surface should be more poke at low temperature solder, for a slagging, especially severe slagging of the site should be promptly dealt slagging.
Sometimes furnace ash side along the direction of disk rotation movement, which are mainly in the case of large slag blocks, due to the large slag blocks between the base and the furnace skirt, not break, the residue block is squeezed transmission, there is always a residue block at the low temperature region, and the side ventilation particularly strong and a high temperature region.
5 Conclusion
In the event of furnace operation, maintain the correct stable furnace conditions, normal production for Gasifications security is critical, and helps to reduce the consumption of coal resources, running hot and cold running operation and partial operation is not often encountered in the normal furnace conditions, the above analysis is only furnace itself runs hot and cold running operation and partial direct causes and treatment methods, but gasification is a system composed of many sub-systems are often reflected in a branch system failure is caused by another sub-systems, the need analysis to find out the source of the fault system, which effectively troubleshooting. For example, exit gas temperature is too high, the direct cause of the oxide layer is generally due furnace slag or caused to move, but the subsequent purification equipment or gas pipeline blockage is often the source of failure is caused by factors, therefore, only the first clear the blockage site in order to adjust the normal furnace conditions, otherwise fruitless. Gasifier Operator only a combination of the whole system integrated, the correct analysis of its origin and formation mechanism of failure to symptomatic treatment, so as to effectively ensure the normal production state.