TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The inorganic acids comprise sulfuric acid, sulfonic acid, phosphoric acid, phosphonic acid, nitric acid, nitrous acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid and/or hydriodic acid. The caustic solution comprises sodium hydroxide and/or potassium hydroxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The treatment of biomass feedstock with hot compressed liquid water (HCW) is performed at a subcritical condition. The method further comprises: adding an additive comprising a dispersing agent and/or a caustic solution, before a separation of a liquid phase from a solid phase; subjecting the biomass feedstock to a subsequent quenching step; adding inorganic and/or organic acids to the biomass feedstock before and/or during the liquefaction; removing non-solubilized material; preventing, minimizing or eliminating clogging and/or fouling of sticky biomass components in process equipment, where an alkaline liquid is washed through the process equipment, either as a sole solution between regular process operations of a biomass process flow in a liquid solution, or as added directly into the liquid solution for dissolving biomass components that are become sticky. The quenching step is performed: to avoid continued detrimental decomposition by the injection of water into a monomer and/or oligomer sugar mixture solution that is produced after the treatment of biomass feedstock with hot compressed liquid water (HCW); by flash cooling; by injection of water into the monomer and/or oligomer sugar mixture solution to a post-quenching temperature of below 165 degrees C (preferably 150 degrees C); and so that the post-quenching temperature is reached within maximum 10 (preferably 2) seconds. In the method an oxidizing agent is added to the alkaline liquid. The liquid lignin components or liquid lignin derivative components are solidified instantly by rapid cooling of the solution. The step of liquefaction is performed at a temperature of at least 200 degrees C (preferably 220-280 degrees C) sequentially in at least two separate reactors, where separation of the liquid phase is performed after each reactor. The alkaline liquid is: processed separately from the biomass process flow solution after its washing or addition steps; recovered after its washing or addition steps for further washing or addition; and a liquid based on caustic liquor (sodium hydroxide) or ammonia. The pH value of the liquefaction step is 1-4 (preferably 1.2-3.3). The pH value is increased during and/or after the liquefaction to slow down or quench the liquefaction reaction by the use of a base. The reaction time of the liquefaction is set to below 1 minute (preferably 1-45 seconds). Preferred Components: The organic acid comprises aliphatic carboxylic acids, aromatic carboxylic acids, dicarboxylic acids, aliphatic fatty acids, aromatic fatty acids and/or amino acids. The liquid lignin components or liquid lignin derivative components are solidified into microparticles. The produced solid lignin components or lignin derivative components are separated. The dispersing agent comprises lignosulfonates, polyacrylates, sulfonates, carboxylates, salts of lecithin, and a co-polymer of a sulfonated acrylate and maleic acid (SASMAC). The lignosulfonates include ammonium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, magnesium lignosulfonate and/or ferrochrome lignosulfonate.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polyacrylate includes: sodium, potassium, lithium and/or ammonium polyacrylates; and polymers formed from the acrylate monomers acrylic acid, methacrylate, acrylonitrile, methyl acrylate, ethyl acrylate, 2-chloroethyl vinyl ether, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylate and/or trimethylolpropane triacrylate.