A driving experience
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I drove by there a long time ago; please discuss whether this is correct: the system’s production capacity is 25,000 tons per year. Minor repairs during the day shift include: replacing the boiler induced draft fan coupling, converting the remaining boiler to serve only gas production purposes, removing the synthetic soft water heater, and upgrading the desulfurization system. For the middle shift handover, everything was basically completed except for the induced draft fan, which was repaired at 5:50. 5:50 – Boiler pressure starts to rise ； 6:52 – Boiler pressure is 10 kg; low-pressure steam is supplied. At the same time, the gas generation process is initiated, the fan is started, and a water seal at the inlet of the exhaust cabinet is used to generate gas ； 7:00 Water seal at exhaust cabinet outlet ； 7:10 – Supply high-pressure steam, start the Roots blower ； Three units (L3.3-17/320) start at 7:17, 7:22, and 7:35 for pressure adjustment ； 7:37 – Switch to 9 kg (operating pressure of 14.5 kg); start cooling output, and initiate carbonization process ； 7:44, 7:46 – Pressure replenishment for the two refining units (pressure had been released during shutdown) ； 7:58 – Refine 50 kg; start the copper pump to generate refining gas ； 8:00 – Add ammonia for cooling in the refined ammonia process, and start up the system while absorbing ammonia ； 8:05: Refine 75 kg; switch to one unit for refining the gas, with another unit used for conversion (notify to release air due to high conversion pressure) ； 8:52 – Refined gas meets specifications; pressure restoration via single-unit synthesis ； 8:58 Second machine pressure replenishment ； At 9:50, the synthesis pressure was increased to 150 kg; the gas supply for synthesis was shut off. The electric furnace was moved while the pressure was reduced, and at the same time, the system was emptied for machine conversion, and carbonization was stopped ； 10:40: Combine stages 1 and 2 at 420 degrees; use one unit to produce refined gas ； 11:10 One-machine synthesis ； 11:16 Two-machine synthesis ； 11:25 Three-machine synthesis ； The shift handover showed three units, with the synthesis temperature being basically normal.
I don’t see any problems; the operation is going smoothly. The time required to produce refined gas is also short, and the temperature increase during synthesis is normal as well. It seems a bit hasty to add carbon at 9 kilograms – after that, the pressure will drop significantly in a short time. If we use three units to replenish the pressure, perhaps waiting another two minutes will allow the pressure to rise above 13. When the synthesis pressure reaches 150, I won’t carry out any pressure reduction measures. It’s possible that our electric furnace has sufficient power to allow heating at this pressure; however, if we release gas while keeping the furnace running, wouldn’t that result in heat loss as well? The reason why only three units are used in the final stage might be that the inert gas content in the synthesis circuit is too low, making it difficult to control the temperature, so no additional gas is added. In such cases, the key in synthesis is to increase the methane content. Of course, methane is accumulated over time, so it’s necessary to accelerate the reaction (by controlling parameters like ammonia cooling temperature and increasing the space velocity), while also reducing gas losses (by controlling the ammonia release level and pressure). The overall process of starting up the system is similar to ours: three units are used for conversion, then two units for refining – only one unit remains during refined gas production, with another unit used to maintain pressure during conversion. Once the refined gas meets the standards, all three units are used sequentially to replenish pressure in the synthesis process. After the synthesis system is pressurized, the previous stage stops, and once the temperature of the synthesis bed rises to 320 degrees, additional gas can be supplied. The amount of load depends on the impact of synthesized methane on the temperature. This post was last edited by chen3jun on 2009-3-29 at 17:49