The invention relates to a process for isolation of hemicelluloses from biomass pulping process waters or spent liquors with removal of suspended solids, concentration of the product and purification of the product by removal of inorganic salts and low molecular weight substances. It is characterized in that the hemicellulose isolation process conditions at several separation/purification stages are adjusted separately by e.g. pH adjustment. The invention further relates to a plant for carrying out the process. With such process and plant it is possible to recover most of the suspended solids, especially xylan and other hemicelluloses.

The invention relates to a process for isolation of hemicelluloses from biomass pulping process waters or spent liquors with removal of suspended solids, concentration of the product and purification of the product by removal of inorganic salts and low molecular weight substances. It is characterized in that the hemicellulose isolation process conditions at several separation/purification stages are adjusted separately by e.g. pH adjustment. The invention further relates to a plant for carrying out the process. With such process and plant it is possible to recover most of the suspended solids, especially xylan and other hemicelluloses.

A deicer composition is disclosed. The deicer composition may comprise water, a metal chloride salt, and a biopolymer composition derived from wheat straw, alfalfa, or other cereal grain straws. The biopolymer composition may include inorganic material and a copolymer comprised of lignin and polysaccharides. The biopolymer composition may have an average molecular weight of between 3500 and 5500 Daltons. The metal chloride salt may be selected from magnesium chloride, calcium chloride, and sodium chloride.

The method in a recovery boiler comprises estimating the first melting temperature T.sub.0 of the fly ash depositing on heat transfer surfaces, the estimating being based on potassium (K) content of the fly ash; measuring or estimating the temperature T.sub.ss of superheated steam; evaluating a temperature difference T.sub.D1 between the first melting temperature T.sub.0 and the temperature T.sub.ss of the superheated steam, the temperature difference T.sub.D1 providing an estimate of the risk of corrosion; and selecting a control action for influencing the temperature difference T.sub.D1. Alternatively or additionally, the method comprises estimating the sticky temperature T.sub.STK of the fly ash depositing on heat transfer surfaces, the estimating being based on potassium (K) and chlorine (Cl) contents of the fly ash; measuring or estimating the temperature T.sub.FG of the flue gases; evaluating a temperature difference T.sub.D2 between the sticky temperature T.sub.STK and the temperature T.sub.FG of the flue gases; the temperature difference T.sub.D2 providing an estimate of the risk of plugging; and selecting a control action for influencing the temperature difference T.sub.D2.

The invention relates to a heat transfer tube (9) for falling film evaporation having a heating medium surface (21) to be heated by a heating medium, a falling film surface (20) to have spent liquor passing over it, and being made from an sheet metal material. The falling film surface of the heat transfer tube is equipped with a multitude of wire bumps (WB), each wire bump being spaced apart along the longitudinal axis (CC) of the heat transfer tube from a neighbouring wire bump by 3-300 mm, said wire bumps (WB) having a height (h) in the range 0.3 to 5.0 mm, a width (w) in the range 0.3-5.0 mm, and an inclination angle (a) versus a plane orthogonal to a longitudinal axis (CC) of the heat transfer tube in a range of 0-70 degrees. The invention also relates to a method for manufacturing said heat transfer tube.

The invention relates to a heat transfer tube (9) for falling film evaporation having a heating medium surface (21) to be heated by a heating medium, a falling film surface (20) to have spent liquor passing over it, and being made from an sheet metal material. The falling film surface of the heat transfer tube is equipped with a multitude of wire bumps (WB), each wire bump being spaced apart along the longitudinal axis (CC) of the heat transfer tube from a neighbouring wire bump by 3-300 mm, said wire bumps (WB) having a height (h) in the range 0.3 to 5.0 mm, a width (w) in the range 0.3-5.0 mm, and an inclination angle (a) versus a plane orthogonal to a longitudinal axis (CC) of the heat transfer tube in a range of 0-70 degrees. The invention also relates to a method for manufacturing said heat transfer tube.

An apparatus comprising a cleaning rod driven in reciprocating, axial extension (y) and retraction (x) movements upon cleaning a smelt discharge opening of a chemicals recovery boiler, wherein a linear actuator is controllable for driving the cleaning rod in the axial movements. A pivot actuation means is controllable for pivoting the cleaning rod about an axis (S) upon cleaning a smelt spout associated with the smelt discharge opening, wherein one or more sensors are arranged to provide control basis for correlation of the axial movements (x; y) with the change in pivot angle () during pivoting of the cleaning rod. A method to be performed in use of the apparatus is likewise disclosed.

The invention relates to a heat transfer tube (9) for falling film evaporation having a heating medium surface (21) to be heated by a heating medium, a falling film surface (20) to have spent liquor passing over it, and being made from an iron based high alloy stainless steel material with an alloy content above 16.00% for Chromium and above 1% for Nickel. The falling film surface of the heat transfer tube is equipped with one or several protrusions/indentations forming a multitude of stamped bumps (SB) on the envelope surface of a heat transfer tube such that the distance between adjacent stamped bumps (SB) along a line on the envelope surface parallel to the longitudinal axis of the heat transfer tube is within the range of 3 to 250 mm, said stamped bumps (SB) having a height (hp) in the range 0.3 to 5.0 mm, a width (wp) in the range 1.0-20 mm, and an inclination angle (a) versus a plane orthogonal to a longitudinal axis (CC) of the heat transfer tube in a range of 0-70 degrees so that each stamped bump (SB) is inclined and extends along at least a portion of the heat transfer tube or extend within a plane orthogonal to the longitudinal axis of the heat transfer tube. The invention also relates to a method for manufacturing said heat transfer tube.

The invention relates to a heat transfer tube (9) for falling film evaporation having a heating medium surface (21) to be heated by a heating medium, a falling film surface (20) to have spent liquor passing over it, and being made from an iron based high alloy stainless steel material with an alloy content above 16.00% for Chromium and above 1% for Nickel. The falling film surface of the heat transfer tube is equipped with one or several protrusions/indentations forming a multitude of stamped bumps (SB) on the envelope surface of a heat transfer tube such that the distance between adjacent stamped bumps (SB) along a line on the envelope surface parallel to the longitudinal axis of the heat transfer tube is within the range of 3 to 250 mm, said stamped bumps (SB) having a height (hp) in the range 0.3 to 5.0 mm, a width (wp) in the range 1.0-20 mm, and an inclination angle (a) versus a plane orthogonal to a longitudinal axis (CC) of the heat transfer tube in a range of 0-70 degrees so that each stamped bump (SB) is inclined and extends along at least a portion of the heat transfer tube or extend within a plane orthogonal to the longitudinal axis of the heat transfer tube. The invention also relates to a method for manufacturing said heat transfer tube.

A boiler system is provided comprising: a furnace adapted to receive a fuel to be burned to generate hot working gases; a fuel supply structure associated with the furnace for supplying fuel to the furnace; a superheater section associated with the furnace and positioned to receive energy in the form of heat from the hot working gases; and a controller. The superheater section may comprise a platen including a tube structure with an end portion and a temperature sensor for measuring the temperature of the tube structure end portion and generating a signal indicative of the temperature of the tube structure end portion. The controller may be coupled to the temperature sensor for receiving and monitoring the signal from the sensor.