Abstract: A plunger pressure accumulator includes a shell; and a plunger which is adapted to move relative to the shell into an interior space of the shell. The interior space is divided into at least two subspaces, a first subspace of which is suppliable with hydraulic fluid of an external system and a second subspace which is provided with a pressurized gas. Between the plunger and the shell is arranged a slide element upon which the plunger is supported to move to a distance apart from an internal surface of the first subspace and from an internal surface of the second subspace. The plunger pressure accumulator is provided with at least one regenerator which is stationary relative to the shell or the plunger.

Abstract: The invention relates to a method for optimising material recovery in a chemical pulping process. The method comprises treating of cellulosic raw material with cooking chemicals in a cooking step, where lignin is at least partly dissolved into cooking liquid phase and separated from fibres. The lignin is separated from the cooking liquid phase. The separated lignin is used for formation of a treatment composition comprising at the most 1 weight-% of aluminium. A bleaching liquid phase is treated with the treatment composition in order to remove organic humic substances from the bleaching liquid. Organic sludge is formed and it is used for energy production in a chemical recovery step.

Abstract: A plunger pressure accumulator includes a shell; and a plunger which is adapted to move relative to the shell into an interior space of the shell. The interior space is divided into at least two subspaces, a first subspace of which is suppliable with hydraulic fluid of an external system and a second subspace which is provided with a pressurized gas. Between the plunger and the shell is arranged a slide element upon which the plunger is supported to move to a distance apart from an internal surface of the first subspace and from an internal surface of the second subspace. The plunger pressure accumulator is provided with at least one regenerator which is stationary relative to the shell or the plunger.

Abstract: A method for manufacturing alkali metal or alkaline-earth metal formate, starting from a formate anion comprises at least the following sequential steps: A) conversion of a solid anion exchanger to formate form by feeding into it a solution containing a formate anion, B) exchanging the formate anion in the anion exchanger for a replacing anion by feeding into it an alkali metal or alkaline-earth metal salt solution of this replacing anion, C) recovering the alkali metal or alkaline-earth metal formate solution eluted from the anion exchanger during the exchange of the formate anion. The anion exchanger is converted to formate form by feeding into it a sodium formate solution, a formic acid solution or a solution which contains both sodium formate and formic acid. The method can be used for production of potassium formate or calcium formate.

Abstract: In a method for preparing formic acid, methyl formate is prepared with methanol as a reactant.

Abstract: A process for preparing a substantially pure aqueous solution of hydrogen peroxide is described. An impure hydrogen peroxide solution is vaporized in a vaporizer to form a vapor containing hydrogen peroxide and a concentrated hydrogen peroxide solution in equilibrium therewith. The solution also contains impurities. A substantially pure hydrogen peroxide solution is obtained by a partially condensing the vapor containing hydrogen peroxide. In addition to the solution, a residual vapor, in equilibrium with the solution and having a lower hydrogen peroxide concentration, can be condensed in a separate condenser. The concentration of the hydrogen peroxide solution obtained by the process can be regulated, for example, by regulating the condensation efficiency of the partial condensation.