Solid material sealing method
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After drying, D1001 proceeds to D1002 for pyrolysis. During this process, gases such as hydrogen, methane, and carbon monoxide are produced. Therefore, the feed end of D1002 needs to be sealed. Previously, a hydraulic pushing mechanism was used, with pistons moving back and forth to push the material; however, due to the inability to maintain a proper seal, gas leaks could easily occur. Now, we are considering using star-type discharge valves or other devices – do anyone have any good suggestions? Material: Municipal sludge after drying, with a moisture content of around 20%.
The star-shaped discharge valve is one type; another type is called a disk feeder, or in such designs the inlet and outlet are not arranged vertically, with a sealed auger in between.
Since it is placed vertically, what is the temperature on your vertical pipe? What is the pressure in the pyrolysis reaction? It can be done using a star feeder, but this is not recommended; after all, the moisture content is quite high, which may cause sticking and prevent proper separation. It is better to use a disc valve or a water-cooled ball lock valve for sealing – the water-cooled ball lock valve can handle pressures of up to 0.6 MPA
The temperature is around 300 degrees, and the pressure is slightly positive.
20% moisture content is quite low; it’s mostly internal moisture
When we handle the transportation of fly ash for use in power plants, the moisture content of the fly ash on the surface of the vehicles is only 10–20%; it can be shaped into clumps and then disperses again when released. If what you have here is sludge, its viscosity is likely higher than that of fly ash
Spiral, disc, star-type discharge valves and similar devices for continuous discharge still rely primarily on material seals for sealing; I would recommend installing a bypass on the pipeline downstream of the sealing valve in order to safely divert any hazardous gases.
In the end, a star-type discharge valve was used – a discharge valve with a special design – and it’s performing well so far.