In wet gasification, what are the problems if the temperature of the quench water is too low?

This impact still exists; it’s not clear whether the gasification mentioned by the original poster refers to water-coal slurry, so for now I assume it is gasification using water-coal slurry. If the operating pressure is 65 kilograms, a quench water temperature of 140°C entering the furnace is indeed a bit low. Using excessively cold quench water in the furnace does help to prevent water from entering the gasification furnace, but it also leads to a decrease in the temperature of the gas exiting the furnace, as well as a drop in the temperature of the gas entering the subsequent washing tower. As a result, the water-gas ratio of the gas also decreases. The water-gas ratio is an important parameter for the shift converter; too low a water-gas ratio can easily cause overheating in the shift converter, and it can also affect the conversion rate of CO in the shift reaction to some extent. Furthermore, excessively low quench water levels can also disrupt the thermal balance of the vaporization water system, leading to problems in the flashing system, such as a decrease in the amount of flash vapor.

Moderator, what I’m saying is correct: it refers to the gasification of water-coal slurry at 65 bar. The original design involved using the syngas obtained after secondary conversion to heat the liquid that results from flashing, with this heated liquid being used as quench water in the gasifier. Some people have suggested using this heat to warm other materials; in that case, the temperature of the liquid after flashing would be around 140–160°C. According to the moderator’s instructions, what is the minimum water-to-carbon ratio required for these changes, and what is the lowest appropriate temperature for rapid cooling?

There is more than one type of conversion device; there are medium-temperature conversions as well as low-temperature conversions. For example, full conversion of CO is used in the production of synthetic ammonia, while partial conversion of CO is employed in the production of methanol. What I want to say here is that different transformations require different water-to-vapor ratios. I remember that a water-to-vapor ratio adjustment of only 0.3–0.4 is sufficient in some cases, but to determine which type of adjustment is appropriate in the given situation, it’s necessary to consult relevant design documents or contact the design firm directly. As for the lowest acceptable temperature for the cooling water, this relates to the overall thermal balance, and the design firm will need to conduct calculations to determine the appropriate balance for the system. Also, in the quench water of the gasification furnace, the main water supply can’t be just the shift condensate, right?

Changes used for hydrogen production, rate of change > 95%

If the temperature of the quench water is low, less quench water can be used; this will also help to maintain a constant temperature of the gas coming out of the vaporization furnace. The level of quench water temperature is related to the design of the quenching ring. If the amount of quench water is too low, its cooling effect in the downcomer deteriorates, resulting in dead zones. High-temperature gas can erode the quenching ring and the downcomer, significantly reducing their lifespan, leading to frequent repairs, increased costs, higher labor intensity, and greater safety risks.