Abstract: Some variations provide a pressure vessel comprising: a chamber for processing a material under a chamber pressure up to 5000 bar; an end cap disposed at one end of the pressure chamber; an interior seal plate disposed between the end cap and the chamber volume; and a plurality of pressure-vessel keys disposed between the end cap and an outer ring. At a chamber pressure greater than atmospheric, the end cap exerts a force against the keys to automatically and reversibly actuate a pressure-vessel seal. Conversely, at atmospheric pressure or less, the keys and end cap are easily removable. Essentially, the pressure in the vessel is utilized as an in situ mechanical force to automatically actuate a safe and efficient seal. Process cycle times are significantly reduced because the vessel is not opened and closed using tooling. Throughputs are increased, improving economics of pressure vessels for extraction, reaction, or other processes.

Abstract: Some variations provide a system for extracting a product from biomass, comprising: a process chamber having an internal volume; one or more mechanical elements configured to controllably and reversibly mechanically seal the process chamber and reduce the internal volume to mechanically compress the biomass; a fluid port in flow communication with the process chamber; and a collection sub-system in flow communication with the fluid port. Other variations provide a method of extracting a product from biomass, the method comprising: introducing biomass into a process chamber; mechanically sealing the process chamber; mechanically compressing the biomass to release a first fluid material; mechanically decompressing the biomass; introducing an extraction solvent into the process chamber; maintaining process-chamber pressure from about 1 bar to about 1000 bar, wherein the extraction solvent extracts a second fluid material; and recovering the second fluid material from the process chamber.

Abstract: Some variations provide a system for extracting a product from biomass, comprising: a process chamber having an internal volume; one or more mechanical elements configured to controllably and reversibly mechanically seal the process chamber and reduce the internal volume to mechanically compress the biomass; a fluid port in flow communication with the process chamber; and a collection sub-system in flow communication with the fluid port. Other variations provide a method of extracting a product from biomass, the method comprising: introducing biomass into a process chamber; mechanically sealing the process chamber; mechanically compressing the biomass to release a first fluid material; mechanically decompressing the biomass; introducing an extraction solvent into the process chamber; maintaining process-chamber pressure from about 1 bar to about 1000 bar, wherein the extraction solvent extracts a second fluid material; and recovering the second fluid material from the process chamber.