Ignition of the space furnace

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Is it necessary to perform gas replacement before heating up the space furnace, and how should operations be carried out when feeding materials after the heating is complete? Gasification Knowledge Question Bank 1: Essay Questions 2. Explain why pressurized operation is commonly used for gasification reactions in production Answer: 1) Pressurized gasification increases the concentration of reactants, accelerates the reaction rate, and improves the gasification efficiency. 2) Pressurized gasification helps to enhance the atomization quality of water-coal slurry. 3) Under pressure, the volume of gases decreases; thus, with unchanged gas production, the size of the equipment can be reduced, minimizing the required floor space and allowing for higher gas output per furnace, which facilitates larger-scale operations. 4) Pressurized gasification can reduce power consumption. What are the economic indicators for the operation of a gasification furnace? Answer: 1) Gas production rate 2) Carbon conversion rate 3) Hydrogen conversion rate 4) Effective gas production rate 5) Coal consumption, oxygen consumption. What phenomena occur when the quenching chamber contains liquid? Answer: 1) Fluctuations in TIA1309 2) Fluctuations in PIA1308 3) Decrease in flow rate of FICA1312 4) Drop in liquid level in the quench chamber 5) Increase in liquid level of LICA1308. What are the causes of the high value of TIA1309 and how to address it? Answer: 1) Low FICA1308 value: Treatment – A: Increase the flow rate of the quench water at FICA1308; B: Check the operating condition of P1303. If FICA1310 drops to 120 cubic feet per hour, start both quench water pumps. 2) Low liquid level in the quench chamber: Treatment – A: Verify that the flow rate at FICA1308 is normal; B: Verify that the flow rate at FICA1312 is normal; C: Check the level gauges LIA1301, LIA1302, and LIA1303. Flush the level gauges if necessary, and also refer to the on-site level gauges. 3) Dust accumulation on the support plates: Treatment: Increase the amount of water used for spraying on the support plates. 4) High-temperature syngas taking a shortcut: Treatment: Shut down the furnace. 11. What factors cause the thermal probe protective sleeves in gasifiers to break frequently? Answer: 1) Rapid heating or cooling of the gasifier leads to uneven thermal expansion on the inner and outer surfaces of the thermal probe sleeve, which can cause it to break. 2) Hydrogen corrosion. 3) If the sleeve extends outside the lining, it is prone to deformation and damage due to the impact of high-temperature gases. 4) High furnace temperature. 12. Thermal probes in gasifiers cannot be used for long periods of time. From which aspects can one determine the furnace temperature in normal operations? Answer: 1) CH4 content 2) CO2 content 3) Check the shape of the slag 4) Empirical data on the oxygen-carbon ratio. 13 What preparations are needed to disassemble the burner? Answer: 1) Release to atmospheric pressure and purge with nitrogen until it is satisfactory. 2) Start the start-up extractor. 3) Connect the cooling water hose for the burner. 14 Describe the working principle of the start-up extractor and the separation tank. Answer: The start-up extractor consists of a steam nozzle, a reducing tube, a mixing chamber, and an expanding tube. Working steam is ejected from the steam nozzle under high pressure; its static pressure energy is converted into kinetic energy, thereby creating a negative pressure in the expanding tube that draws in the fuel. The gas drawn in mixes with the steam in the mixing chamber before entering the expanding tube, where the velocity gradually decreases and the pressure increases. The kinetic energy is then converted back into static pressure energy before the mixture is discharged. 15 Analysis of the causes and solutions for overheating of the gasifier wall. Answer: Phenomenon: Temperature exceeds the specified limits or there is rapid local overheating, triggering an alarm. Causes: 1) Excessively high operating temperature of the gasifier. 2) Partial detachment of refractory bricks. 3) Air leakage due to improper sealing of bricks, causing airflow shortcuts. 4) Incorrect readings from surface temperature sensors. Solutions: 1) Adjust the slag outlet pressure difference to normal levels; prevent blockages at the slag outlet and reduce the ash melting point of the coal slurry. 2) Check the accuracy of the surface temperature sensors. 3) Shut down the system, remove the burner to inspect the refractory bricks, and repair any damaged areas. 16 Describe the structure and working principle of the process burner. Answer: The process burner has a three-stream sleeve structure. A cooling coil is located at the nozzle, oxygen flows through the central tube, the coal slurry flows through the gap in the middle sleeve, and oxygen also flows through the gap in the outer sleeve. Working principle: Oxygen from the central tube and the outer sleeve, along with the coal slurry, mix together at the nozzle. Under the influence of oxygen, the coal slurry is sprayed into the gasifier in the form of a high-velocity mist, thus achieving atomization of the coal slurry. 17 What are the hazards of internal leakage at the inlet and outlet of the lockhopper pump? Answer: During slag discharge, internal leakage at the inlet and outlet of the hopper pump causes a drop in pressure within the pump. Once XV1308 is opened after slag discharge is complete, this can exert significant stress on the pump, leading to damage to the hopper circulation pump. What is the reason for poor drainage of high-flash liquid when the gasification furnace is started? Answer: 1) During operation, temperature changes cause scale particles within the equipment to fall off and block the high flash point liquid discharge pipeline. 2) The opening degree of LV1403 is low, resulting in the accumulation of larger scale particles that block the area in front of the valve. 3) When the system is shut down, LV1403 is not opened fully in time to utilize the pressure difference for removing scale.

Two terms explained:
1. Flashing: The solubility of gases in water decreases as pressure drops; the lower the pressure, the lower the boiling point of water. This principle is utilized to evaporate the gases and water present in the black water, thereby separating them from impurities.
2. Ash content: It refers to the percentage of the weight remaining after a coal sample is burned at a constant temperature of 800±20°C until it reaches a constant weight.
3. T4 temperature: This refers to the temperature at which the viscosity of the ash slurry is between 25–40 PaS.
4. Cavitation: The phenomenon where a pump fails to deliver fluid due to the vaporization of liquid is called cavitation.
5. Cascade control: In a control system, there are two controllers, each receiving measurement signals from different parts of the process. The output of one controller serves as the setpoint for the other controller, whose output then controls the control valve in order to adjust the process parameters. Structurally, these two regulators operate in series; therefore, such a control system is called a cascade control system