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.

A waste organic solids burner integrated with an ethanol plant includes a burner receiving waste organic syrup, combustion air dryer exhaust and natural gas from the ethanol plant. A baghouse receives burner exhaust and extracts particulate matter and hot gas, which is sent to a waste boiler. Cool gas from the waste boiler is sent to a heat recovery scrubber, from which hot water is sent to the ethanol plant as an energy source.

A waste organic solids burner integrated with an ethanol plant includes a burner receiving waste organic syrup, combustion air dryer exhaust and natural gas from the ethanol plant. A baghouse receives burner exhaust and extracts particulate matter and hot gas, which is sent to a waste boiler. Cool gas from the waste boiler is sent to a heat recovery scrubber, from which hot water is sent to the ethanol plant as an energy source.

An apparatus for the destruction of a precursor material includes a steam plasma reactor having a high temperature zone and a combustion zone. The high temperature zone is adapted for hydrolyzing the precursor material, whereas the combustion zone is adapted to effect medium temperature oxidation of the reactant stream where combustion oxygen or air is injected. A quenching unit is provided at an exit end of the reactor for quenching a resulting gas stream to avoid the formation of unwanted by-products.

An apparatus for the destruction of a precursor material includes a steam plasma reactor having a high temperature zone and a combustion zone. The high temperature zone is adapted for hydrolyzing the precursor material, whereas the combustion zone is adapted to effect medium temperature oxidation of the reactant stream where combustion oxygen or air is injected. A quenching unit is provided at an exit end of the reactor for quenching a resulting gas stream to avoid the formation of unwanted by-products.

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.

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.

An arrangement in a recovery boiler having a furnace for combusting waste liquor and a flue gas duct including vertical flue gas channels, at least some of which are provided with heat recovery units for recovering heat from flue gases. The first flue gas channel downstream of the furnace is provided with a reheater and one of the following heat recovery units: an economizer or a boiler bank. The reheater and the second heat recovery unit are located one after the other in the horizontal incoming direction of the flue gas, so that in a flue gas channel the flue gas flows in a vertical direction from above downwards and heats the reheater and the second heat recovery unit simultaneously. The heat recovery elements of the reheater and the second heat recovery unit may be positioned side by side in a direction that is crosswise with respect to the horizontal incoming direction of the flue gas.

An arrangement in a recovery boiler having a furnace for combusting waste liquor and a flue gas duct including vertical flue gas channels, at least some of which are provided with heat recovery units for recovering heat from flue gases. The first flue gas channel downstream of the furnace is provided with a reheater and one of the following heat recovery units: an economizer or a boiler bank. The reheater and the second heat recovery unit are located one after the other in the horizontal incoming direction of the flue gas, so that in a flue gas channel the flue gas flows in a vertical direction from above downwards and heats the reheater and the second heat recovery unit simultaneously. The heat recovery elements of the reheater and the second heat recovery unit may be positioned side by side in a direction that is crosswise with respect to the horizontal incoming direction of the flue gas.

Processes for stabilizing toluenediamine residues are disclosed. These processes include adding a low viscosity, low boiling liquid to a toluenediamine residue composition to form a blend, and optionally, continuously monitoring the viscosity of the blend during addition of the low viscosity, low boiling liquid. The low viscosity, low boiling liquid may be added at 5% to 30% by weight based on the total weight of the blend. Further, the low viscosity, low boiling liquid may be added so that the blend has a viscosity of 10,000 cP or less throughout the temperature range of 40 C. to 95 C. Blends of toluenediamine residue compositions and low viscosity, low boiling liquids such as water, and methods of their use as a fuel are also disclosed.