NOVELTY - Processing plant biomass involves: extracting lignin from plant biomass using solvent to generate black liquor; separating lignin from liquor; removing cellulosic residue generated after lignin extraction; producing slurry from residue; feeding the slurry to bio-convertor to convert the cellulosic and other cellular biological material into hydrocarbon oil sludge; recovering bio-crude from hydrocarbon sludge by extraction; and sending residual sludge remaining after extraction of bio-crude to fertilizer plant to recover high phosphate fertilizer product.    USE - For processing plant biomass comprising woody plant biomass (selected from plantation forestry, plantation crops such as vineyards, orchards, palm oil plantations, grasses, sawmills, wood fiber and urban waste) to recover hydrocarbon oil and high phosphate fertilizer product (claimed). The hydrocarbon oil is used to produce e.g. chemical, petrochemical, oil and transport fuel products.    ADVANTAGE - The lignin extractor is capable of processing wood chips to remove lignin and the bioconverter that uses a super critical water process to covert the cellulosic waste to produce biocrude. The process leaves a sludge, which is converted to a high phosphate fertilizer. The re-usable solvents can be used to extract lignin and supercritical water to produce biocrude. The super critical water process can be linked directly to the cellulosic wood waste to produce a crude oil which can then be distilled to yield a range of high value chemicals, oil and transport fuel products.    DETAILED DESCRIPTION - Processing plant biomass involves: extracting lignin from plant biomass using a solvent to generate a black liquor; separating the lignin from the black liquor; removing cellulosic residue generated after the lignin extraction; producing a slurry from the cellulosic residue and optionally combining with other organic materials not containing lignin; feeding the slurry to a bio-convertor to convert the cellulosic and other cellular biological material into a hydrocarbon oil sludge; recovering bio-crude from the hydrocarbon sludge by extraction; and sending residual sludge remaining after the extraction of bio-crude to a fertilizer plant to recover high phosphate fertilizer product. INDEPENDENT CLAIMS are included for the following:    (1) processing (M1) of plant biomass;    (2) processing of plant biomass involving: extracting lignin from plant biomass using a solvent to generate a black liquor; separating the lignin from the black liquor; removing cellulosic residue generated after the lignin extraction; producing a slurry from the cellulosic residue; feeding the slurry at high pressures to a bio-convertor to convert the cellulosic and other cellular biological material into a hydrocarbon oil sludge; adjusting and equalizing pressures across valves (V1, V2) in conditions of high gaseous content, by installing equalization cylinders upside down to enable surplus gas to be rapidly flushed out; controlling valves proximate the bioconverter to rapidly open valves at the instant of minimum pressure difference between opposite sides of valves; and recovering bio-crude from the hydrocarbon sludge by extraction;    (3) equalizing pressure of a flow stream across a valve involving: providing a process valve having an abrasive flow stream with a first pressure on a pump side and a second pressure on a second side of the process valve; providing a pump upstream from the pump side of the process valve; providing a slave cylinder in fluid connection with the abrasive flow stream downstream from the second side of the process valve, where the fluid connection with the abrasive is connected to a top portion of the slave cylinder; arranging a needle valve along a first non-abrasive fluid line between the pump and the slave cylinder; and actuating the needle valve to permit flow between the slave cylinder and the pump, so that the first pressure with the second pressure are equalized;    (4) a system for equalizing pressure of a process flow stream across a valve comprising: a process valve having an abrasive flow stream with a first pressure on a first side and an abrasive flow stream with a second pressure on a second side; a pump upstream from the first side of the process valve; a slave cylinder in fluid connection with the abrasive flow stream downstream from the second side of the process valve, the fluid connection being connected to a top portion of the slave cylinder; a valve disposed to control flow of a non-abrasive fluid line between the slave cylinder and the pump; where upon actuation of the needle valve, the fluid flow is permitted between the slave cylinder and the pump thereby equalizing the first pressure with the second pressure;    (5) processing of plant biomass involving: extracting lignin from plant biomass using a solvent to generate a black liquor, where the wood chips being fed to a top inlet of a counter current extraction column comprising a series of vertically aligned valves, and the solvent being fed into a bottom inlet of the counter current extraction column, the valves being operated sequentially to transfer wood chips down the column while providing cooking periods for extracting lignin; opening a containment valve disposed at the top of the counter current extraction column, above a valve housing a top level cooking chamber (1', 2') of the column, to feed wood chips to the top inlet; opening a containment valve downstream of valve that houses a bottom cooking chamber of the counter current extraction column, to remove pulp; separating the lignin from the black liquor; and recovering and recycling the solvent from the black liquor; and    (6) a plant for processing plant biomass comprising: an extraction unit for extracting lignin from plant biomass; a high pressure bioconverter reactor for converting residue from the extraction unit; several pressure equalization cylinders fluidly connected to the bioconverter; a control system for controlling at least one valve proximate the bioconverter to rapidly open the at least one valve at the instant of minimum pressure difference between opposite sides of the valve; and a recovery section for recovering bio-crude from hydrocarbon sludge generated by the bioconverter.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of the method for extracting lignin from wood chips.    Heat exchanger (4)    Lignin extraction unit (8)    Cooler (10)    Auger (20)    Cooking chambers (1', 2')    Valves (V1, V2)