A valve brief for a coal gasification project

The first ceramic design did not solve every black-water position. At an Inner Mongolia gasification project, inspections led KOWOV to replace a C-type arrangement with a sliding design in some of the most erosive control duties.

That progression is the most useful part of the case. It shows how different positions inside one plant can require different flow paths, even when they handle related media.

One project, several valve jobs

The published account describes a 1.2-million-tonne-per-year fine-chemical demonstration project with six pulverized-coal gasifiers and three coal-water-slurry gasifiers. Their associated valve duties included coal-feed pressure control, black-water flow regulation and flash-tank or scrubber level control.

The numbers describe the project context. They do not define the pressure, temperature or solids loading at an individual valve. Each position needs its own operating description.

Coal-feed pressure control

At position 23602-PV-x128B, the plant used a valve to control the pressure of a pulverized-coal feeding tank. The account records an earlier replacement interval of about three months and the introduction of a ceramic ball valve in October 2017.

The ceramic valve remained in use until a process change, according to the source. The exact operating duration is not stated, so the process change should not be turned into an invented lifetime figure.

Black water drove a change in geometry

Black-water flow-control positions 23701-FV-x008 and 23200-FV-00808A handled solids affected by the coal quality. The earlier eccentric-rotary valves reportedly suffered severe erosion within about 6–8 months.

KOWOV ceramic valves entered the pulverized-coal system in August 2018 and the coal-water-slurry system in October 2019. The C-type valves used at those stages reached a reported maximum service interval of about twelve months, but inspections still found substantial erosion.

A ceramic slide-valve solution followed in late 2020. The account records an average service interval exceeding 24 months for the revised arrangement at the relevant positions.

The current FCSV ceramic slide valve uses a flat slider and fixed seat at the edge of the flow passage. Separating the valve opening from the pipe opening is intended to reduce direct erosion of the sealing surfaces. That construction explains the design direction taken in the case.

Level-control positions followed

In January 2022, ceramic slide valves replaced earlier ceramic ball valves at the low-pressure flash-tank level-control positions 23300-LV-00703A/803B/903C. The report also describes a scrubber-tower level-control position, 23200-LV-02112A, initially using a ceramic ball valve in October 2019 and later moving to a sliding arrangement.

These changes should not be read as a rule that one valve type always outperforms another. The FCRV ceramic C valve remains relevant to other difficult-media duties. The evidence here is that the erosion pattern at these positions justified a different geometry.

Give the supplier the pressure and flow history

For a black-water or gray-water enquiry, provide the valve position, solids description, upstream and downstream pressures, temperature and full flow range. Explain whether the valve controls flow, pressure or vessel level, and include its normal opening.

The FCCV5 ceramic ball valve offers another construction for demanding temperature and pressure conditions. KOWOV can compare that route with FCSV and other designs using the actual duty.

The lock-hopper depressurization account gives a contrasting gasification example where an FCCV5 installation developed a long service record. Together, the cases make the selection question more precise: which construction protects the working surfaces under this particular flow path and cycle?