The role of the steam/oxygen mixer in the shell gasification process
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May I ask everyone, what is the role of the steam/oxygen mixer in the shell gasification process? Why is oxygen mixed with medium-pressure superheated steam in the steam/oxygen mixer before entering the coal-fired burner? Is it to create a protective zone around the burner in order to prevent it from being ablated in a high-temperature, high-oxygen environment? Please, experts, give me some advice
Reducing the concentration at the burner’s inlet and increasing the volume of the mixture raises the flow rate of the gas entering the furnace, thereby pushing the flame further away from the burner and reducing the damage caused by intense radiant heat to the burner. There must be many other benefits as well. :) :L
1. Its main function is to provide the water vapor required for the gasification reaction. 2. It can objectively increase the flow rate at the nozzle, which facilitates the dispersion of coal powder and thus helps to improve the conversion rate. 3. Its role in protecting the burner is minimal.
Mixing oxygen and steam allows the gasifying agent to enter the gasification furnace after passing through just one flow channel. At the same time, oxygen and steam mix well together, raising the temperature of the oxygen and increasing the flow rate into the gasification furnace, thereby enhancing the dispersed combustion of coal powder.
Thank you all for your feedback. I checked the inlet and outlet material data for the steam-oxygen mixer here; under normal operating conditions: oxygen, 6.06 kg/s, 180°C, 4.15 MPaG ； Medium-pressure superheated steam, 0.21 kg/s, 300°C, 5.05 MPaG ； The exhaust mixture has a flow rate of 6.27 kg/s, a temperature of 188°C, and a pressure of 4.1 MPaG. In other words, the amount of steam present is very low, so it has little impact on the temperature and pressure of the mixture. Furthermore, I believe the amount of steam participating in the reaction is relatively small, and I am also unsure about the idea that steam mixes with oxygen to form a burner protection zone. I’ve checked previous posts and online materials, but I haven’t found any specific explanations; I hope everyone can share their own opinions.
1. Agreeing that the addition of steam on the 3rd floor is mainly used for the gasification reaction, providing an oxidant that can lower the temperature; this helps control the furnace temperature and increases the conversion rate. 2. The steam/oxygen mixer might be designed in such a way that no additional steam channel is needed for the burner. 3. Mixing with oxygen facilitates better dispersion, resulting in a more uniform and thorough reaction. Just my humble opinion!
The materials I read mentioned something about it also having an effect that helps control the water-to-oxygen ratio
I also asked people around me, and their opinion is that steam can be used to adjust the furnace temperature and the composition of the syngas; I guess it works by participating in the reactions to appropriately regulate the ratio of CO to H2 as well as the temperature of the gasification furnace
1. Adjusting furnace temperature: Different types of coal, due to their varying calorific values, result in different furnace temperatures after reaction. To control the reaction, a certain amount of steam is generally required to regulate the furnace temperature to around 1500 degrees ； 2. The addition of steam to the reactor lowers its temperature; therefore, if the temperature is lowered too much, it will result in an increase in the amount of oxygen available for the reaction ； 3. The addition of steam regulates the composition of the syngas. This increases the amounts of hydrogen and carbon dioxide, while reducing the amount of carbon monoxide. Sometimes it is advantageous for subsequent processes (for example, when it is necessary to adjust the CO/H2 or H2/CO ratio).
Water vapor can also be omitted, though the conversion rate will decrease.
1. The role of protecting the burner is minimal. 2. It prevents uneven mixing and localized overheating.
I work in the field of pulverized coal gasification; the water-to-oxygen ratio is 0.05–0.1. Before mixing, the oxygen pressure is 5.0 MPa at 180° (after preheating in a preheater); the superheated steam pressure is 5.0 MPa at 350°. The pressure of the mixed gas is 4.25 MPa at 205°. It’s certain that there is enough quantity of these substances to participate in the reaction. Internal structure of the oxygen vapor mixer? ? ? The flow channel (central oxygen in the water-coal slurry burner) allows for thorough mixing of oxygen and steam, increasing the flow rate and enabling the coal slurry to be fully atomized; the pulverized coal is thus dispersed for complete combustion, thereby improving the gasification efficiency. There is also talk about protecting the burner
Hello, I would like to ask if there are any regulatory requirements regarding the temperature at which oxygen and steam are mixed – is it true that this temperature must not exceed 200°C?
Hello, I would like to ask if there are any regulatory requirements regarding the temperature at which oxygen and steam are mixed – is it true that this temperature must not exceed 200°C?