① Connect the slag pool water directly into the supply channel of the quench ring of the gasifier through the preheating water pump or connect the quench water supply channel of the raw water directly into the quench ring of the gasifier. After the corresponding liquid level is established in the quench chamber of the gasifier, open the manual stop valve to the overflow water seal of the gasifier. The preheated chilled water flowing into the overflow water seal is discharged into the slag pool through overflow. After the liquid level of the slag pool rises to the normal level, start the slag pool pump to send the water in the slag pool to the clarifier. After the clarifier is full, the overflow is discharged into the ash tank. After the system water circulation is established, start other relevant systems. If the slag pond is insufficient, the water shall be supplemented by raw water.
After the system water circulation is established through the raw water, the preheating burner ignition can be prepared.
How to dry and preheat the refractory for gasifier?
During the preheating of gasifier refractory, if the amount of chilled water entering the gasifier quench ring is too small, it will lead to uneven water distribution in the quench ring and damage to the quench ring or downcomer. During preheating of gasifier or curing of refractory materials, the amount of quench water flowing into the quench ring of gasifier shall not be less than 130th. Nevertheless, during the preheating of gasifier or refractory curing, the flow of quench water can be set at the flow value under normal operating conditions without further adjustment.
② The designed adjustable gasifier overflow water seal is used to maintain the preheating water level in the quench chamber lower than the lower edge of the downcomer and higher than the lower edge of the air duct. The liquid level can be observed from the site through the glass level gauge. If the preheating water level of the quench chamber is higher than the lower edge of the downcomer, the amount of air pumped into the gasifier by the extractor will fluctuate greatly, resulting in unstable combustion or tempering of the preheating burner. If this happens, the amount of chilled water can be appropriately reduced to restore the stability of the system. However, do not interrupt the chilled water, otherwise the downcomer and air duct will be damaged.
③ Turn the blind plate on the pipeline to the start-up extractor to the "through" position. The start-up extractor sends low-pressure steam and opens the stop valve between the crude syngas pipeline and the start-up extractor.
④ Install a U-tube differential pressure gauge on the crude syngas pipeline of the start-up extractor, and adjust the air volume pumped into the gasifier according to the system negative pressure measured by the differential pressure gauge. The negative pressure of the system is controlled by manually adjusting the amount of low-pressure steam to the start-up extractor.
⑤ After the negative pressure of the system is established, the preheating burner can be ignited. If the operator has not fully mastered the use of this type of preheating burner and takes LPG as the combustion medium, it is recommended to ignite the preheating burner outside the gasifier, and then move the preheating burner flame into the gasifier furnace with the help of furnace negative pressure. This method is convenient for the operator to safely ignite the preheating burner and maintain stable combustion during the drying and curing of the refractory materials of the gasifier, and can form an intuitive understanding of the required valve opening and fuel quantity.
Note: before the preheating burner is put into use, the flame monitor must be adjusted to ensure its accuracy and ease of use.
⑥ Dry and preheat the refractory according to the relevant requirements provided by the manufacturer, gradually increase the amount of air, fuel and system negative pressure, and correspondingly increase the drying and preheating temperature of the refractory.
⑦ During the drying, curing and preheating of refractory materials, the gas temperature in the quench chamber of the gasifier shall not be higher than the crude syngas temperature (254.14 ℃) in the quench chamber of the gasifier under the normal operating conditions of the gasifier. During the preheating of gasifier, the gas temperature in the quench chamber of the gasifier is controlled by adjusting the supply of quench water in the quench ring.
If the gasifier is ready to feed within two or three days after reaching the upper limit of its preheating temperature, the refractory of the gasifier can be kept constant at this temperature. If the feeding of gasifier needs to be delayed for a period of time, the refractory of gasifier can be cooled down by gradually reducing or stopping the amount of preheated fuel and inhaled air. In any case, the cooling process of gasifier refractory shall be carried out step by step to avoid "thermal shock" to gasifier refractory. The quench water flowing into the quench ring shall maintain a certain flow until the temperature of the gasifier furnace drops below 150 ℃. After the refractory of gasifier is cooled to normal temperature, the refractory lining of gasifier must be protected by nitrogen filling to prevent the invasion of water vapor in the atmosphere.