Effects of partial load operation on Texaco gasifiers

I also asked my supervisor during my practical training why the load of the vaporization furnace couldn’t be increased gradually from zero load, but to this day I haven’t received a satisfactory explanation. In my opinion, the main limitation lies in the burners, as their size is designed for full load operation; only at full load can the flow rates of the slurry and oxygen meet the design requirements, allowing for proper atomization and a normal flame angle. At half load, the speed of the slurry through the gaps in the burner decreases to half or even less of its original value. With a low initial velocity, the slurry cannot effectively exchange kinetic energy with oxygen, resulting in poor atomization. Operating at half load for an extended period can easily lead to overheating of the furnace walls and severe wear on the refractory bricks. Half load represents the lowest operating load; below this level, the flow pattern inside the furnace becomes irregular, which can easily damage the refractory bricks, and the atomization effect is poor as well, with a low carbon conversion rate. The most important thing is that once the device leaves the factory, its size cannot be adjusted anymore; therefore, it can only be used at half capacity. This is my personal understanding!

At partial load, it definitely affects the atomization effect of the burner. Basically, the gaps in the burner are set based on operation at full load; when operating at partial load, with the same oxygen concentration at the center, the atomization angle inevitably changes

When operating at half load, the system performance is definitely stable and comfortable. However, it cannot also operate at partial load for long periods of time. In partial and full load operation, all consumption factors except for oxygen and coal remain the same; this has a direct impact, and the main concern for management is the high cost. Just this one impact is enough to sting their nerves. Secondly, when the shift converter catalyst is in operation, the raw gas needs to have a certain flow rate in order to carry away the heat generated as a result of the shift reaction. When the load on the gasifier is low, the temperature in the shift converter tends to be high, or even exceed the optimal level; this phenomenon becomes more pronounced as the load decreases. Furthermore, the feeding of the gasifier does not start from 0 load; I believe there are several reasons for this. 1. Limitations of the slurry pump: when a high-pressure slurry pump is started, its rotational speed is not 0 ； 2. At low speeds of the high-pressure slurry pump, the slurry flow rate is low. The slurry flow meter used is an electromagnetic flow meter; under such conditions, this flow meter becomes very unstable and exhibits large errors. I believe everyone understands what it means when a flow meter is unstable ； 3. When the slurry flow rate is very low, the slurry does not necessarily fill the slurry pipeline; there may be gaps in it, and gas or oxygen could backflow into the pipeline, posing a certain safety risk.

The lower the load, and the higher the pressure in the gasifier remains at its original level, the slower the flow rate of oxygen and coal slurry into the gasifier, resulting in poor atomization； Secondly, the mixture resulting from oxygen injection into the coal slurry travels over a short distance; as a result, the reaction takes place relatively close to the tip of the burner, which makes it easier to damage the burner.

The load is low, the coal flow rate and density are unstable, which makes it easy for the burner to malfunction; it is difficult to operate, and the temperature is hard to control, resulting in high operational difficulties and inefficiency