Graywater scaling issue

The sedimentation tank also needs to be properly adjusted; the graywater system is always in a fully circulating mode. The original poster isn’t sure about this, and pipe blockages have indeed been a persistent issue, though to varying degrees. To reduce scaling, it is crucial to add an appropriate and sufficient amount of scale inhibitor

I suspect that the problem is due to the inefficacy of the scale inhibitor; it might be worth trying a different one. Another possibility is that the person responsible for adding the scale inhibitor wasn’t careful enough and was lazy, but this is unlikely – a qualified operator wouldn’t engage in such sloppy behavior. That said, even if the scale inhibitor is added properly, scaling can still occur... In the case of the ash water circulation in the gasification furnace, the process involves the ash water from the gasification furnace and the carbon scrubbing tower entering a flash tank after flashing; the settled ash particles are then removed, while the remaining liquid flows into an ash water tank. From there, it’s pumped under high pressure to a venturi tube and then to the carbon scrubbing tower, from where it’s pumped back into the gasification furnace, thus creating a continuous cycle. Generally, scaling tends to occur more frequently at the flashing point and at the location where cooling water is applied. Of course, there are other factors as well; I’m not sure which pipeline you’re referring to. You could also add more barrels of scale inhibitor, as this will have a noticeable effect and is practical. If you have any different opinions, please feel free to share them: handshake. This post was last edited by Langtaosha on 2008-3-14 08:29

It’s not possible for us to achieve a complete cycle; on the one hand, there is an abundance of water resources, and on the other hand, to maintain water quality, fresh water is continuously added. Additionally, some graywater is sent to wastewater treatment facilities.

The process is more or less the same. This post was last edited by Langtaosha on 2008-3-14 08:30.]

How is it possible to achieve a full cycle? As the cycle time lengthens, the CL content in the water increases, causing equipment corrosion. All of them use a system that delivers over 30 cubic meters of water per hour to the water treatment process. Some water needs to be added to the deaeration tank or graywater tank. The dispersant is simply added at the inlet of the high-pressure ash water pump in the ash water tank. Graywater pipelines are not prone to scaling. Scale formation is inevitable in black water pipelines, so vaporization systems are equipped with cleaning teams. Specialized in cleaning blackwater pipelines. Which factory can prevent scaling in the black water pipelines? Was the one on the 4th floor actually in operation, or is everything else just talk?

On the 4th floor… this is just my personal opinion. Last edited by Langtaosha on 2008-11-29 at 13:04.]

I can tell you for sure that it’s not all cycles, but the vast majority of them! A small portion is sent to the wastewater biological treatment system! Scaling can only be reduced; it cannot be avoided! Depending on the type of coal, region, and medium, different treatment methods are used; generally, scale inhibitors are added. This post was last edited by GSP on 2008-3-14 13:57]

Without discharging graywater, how can the chloride content in the system be balanced?

It’s not possible to achieve a complete cycle; some fresh water must be added, and a portion of the wastewater needs to be sent to the water treatment system.

Agree with what was said above; it’s necessary to add some fresh water. Additionally, I have an idea: perhaps the pH value could be adjusted (SHELL has a system for adding acids or bases).

The temperature in graywater treatment is difficult to control; it stays low!

If the graywater within the system is not discharged, the concentration ratio will increase, which will exacerbate scaling!

Agree with the opinion on floor 6! Which unit is on the 6th floor? The process seems to be the same as ours

I think it’s still due to the pH level of the gray water; excessive alkalinity is what causes scaling. Sometimes we add a slightly acidic substance to neutralize it.

There’s no need to explain further the direction and flow of graywater; a full circulation is impossible, as all systems require fresh water to be added. In our plant, fresh water is introduced from the deoxygenation tank

The scaling problem in the gasification black ash water system is a common issue with complex causes. The main influencing factors include the quality of the local raw water, the actual operating conditions of the system (such as pressure and temperature), as well as the amount of fresh graywater added and the performance of scale-inhibiting dispersants. Generally, it is not possible for systems to achieve full recycling of graywater, as this would lead to increasing levels of hardness, alkalinity, suspended solids, chloride ions, and other substances in the graywater, thereby causing severe scaling and corrosion in the system (chloride ions can cause hydrogen embrittlement in stainless steel equipment). Therefore, compared to a fixed gasification system whose operating conditions are fixed and cannot be changed, it is necessary first to ensure proper flocculation of the black water; the quality of this flocculation process will directly affect the quality of the gray water that results thereafter ； Secondly, a scale and dispersion inhibitor with excellent performance in preventing scale formation and dispersing scale should be selected (based on the operating conditions of the system, requiring resistance to high temperatures, pressures, hardness, and high levels of suspended solids), and this inhibitor should be added to the gray water. At the same time, it is necessary to strictly control the quality parameters of the black and gray water in accordance with the specified requirements; when these parameters reach their upper limits, the water should be drained promptly and fresh water should be added. If the process permits, and depending on the system conditions, the optimal location for adding water treatment chemicals can be selected, which will yield better scale inhibition results. Furthermore, changes in the type of coal will also directly affect the types and contents of solid ash in the black and gray waters. Therefore, the treatment of these waters involves a process of adjusting to such changes in order to achieve good treatment results, thereby ensuring the long-term stable operation of the system in terms of black water treatment.