REDUCE EQUIPMENT/PIPING METALLURGY FROM SS304 TO MS/CS BY NITROGEN BLANKETING IN THE BIOMASS GASIFICATION GAS CLEANUP AREA
Publication Date: 2014-Aug-27
The IP.com Prior Art Database
The instant disclosure proposes to block the gasifier outlet line and engine inlet valve and pass nitrogen through the gas path and vent it through the flare burner. This may eliminate any chances of gas getting trapped in the line, and therefore may remove any opportunity for condensation after the shutdown. Use of nitrogen may prevent oxygen from entering the gas path, which is required to ensure no gas combustion.
Current biomass gasification process requires higher metallurgy post the gasifier outlet line than Stainley Steel 304. This need is due to the possibility of condensation of gas in the piping when the plant is shut down and gas may be bottled up in the section. The reason for this bottle up after shutdown sequence is to ensure no gas leaks out and no oxygen enters the gas line. Combustion can occur if oxygen enters in the gas line at a higher temperature.
The instant invention proposes to block the gasifier outlet line and engine inlet valve by introducing a nitrogen sweep system using the following process (see Figure 1). As soon as the gasifier is sealed during the shutdown and all pumps and scrubbers are closed, ensure closing of the butterfly valve (TSO) at gasifier outlet flange. During the shutdown sequence, the engine inlet gas valve is closed and flare line is opened. Nitrogen can be pumped in by one of the drain valves through gas bottles, and pressure should be checked often to ensure it does not go above about 250 mmWC. At this point, the system can be flushed with nitrogen while the gas is exiting through the flare line. During this process, the CO content should be measured at the burner platform. As soon as CO content dips below 10 ppm, the flare burner valve should be closed and the nitrogen discontinued. The gas line should then be checked for condensation.
This process may ensure the following: No condensable gas present in the line post nitrogen sweep. No corrosion after the plant is shut down in the gas clean-up section. Re...