A powder supply method for causing a powder supplied from a top end 70t of a tube 70 to flow down within the tube 70 and be discharged from a bottom end 70b of the tube, in which if M [kg/s] is a supply flow rate of the powder and A.sub.S [m.sup.2] is a cross-sectional area of the bottom end 70b of the tube 70, the following expression is satisfied.
1.5(M/A.sub.S)135

The invention relates to a method for controlling a flow generator (1) in a tank (20) configured for housing a liquid comprising solid matter, the flow generator (1) comprising an impeller and being located at a height (h-mixer) in the tank (20) and the tank (20) having a predetermined maximum filling height (h-max), wherein the flow generator (1) is configured to be operated at a variable operational speed (n) and the demand of operational speed (n-demand) is dependent on the present liquid level height (h-present) in the tank (20), wherein a max operational speed (n-max) of the flow generator (1) is the operational speed required when the liquid level in the tank (20) is equal to the maximum filling height (h-max), the present operational speed (n-present) being set equal to the demand of operational speed (n-demand) of the flow generator (1) that is determined using the formula: $\left(n-\mathrm{present}\right)=\left(n-\mathrm{demand}\right)=\frac{\left(n-\max \right)}{\left[\left(h-\max \right)/\left(h-\mathrm{present}\right)\right]^a}$ at least when [(h-mixer)+X](h-present)(h-max), wherein a() and a<1, X=radius of the impeller of the flow generator+1, and all heights and measures are given in meter.

The present disclosure relates to a method for converting carbon dioxide into carbon monoxide comprising: producing atomic oxygen, providing carbon dioxide to be converted, mixing the carbon dioxide with the atomic oxygen within a mixing area such that the atomic oxygen can interact with the carbon dioxide for forming carbon monoxide within the mixing area through a first CO producing reaction: C0.sub.2+0.fwdarw.C0+02, supplying the atomic oxygen into the mixing area at a first supply rate and supplying the carbon dioxide into the mixing area at a second supply rate, defining the first supply rate and the second supply rate such that a ratio between the first supply rate and the second supply rate remains within a pre-defined lower and upper threshold, and extracting carbon monoxide from the mixing area. The present disclosure also relates to an apparatus for converting carbon dioxide into carbon monoxide.

A method may include determining a first dry mass flow rate of a wet paper material stream based on a first amount of contaminants, a first moisture content, and a first wet mass flow rate of the wet paper material stream, determining a second dry mass flow rate of a wet plastic material stream based on a second amount of contaminants, a second moisture content, and a second wet mass flow rate of the wet plastic material stream, calculating, using the first dry mass flow rate and the second dry mass flow rate, a paper/plastic ratio of a combined stream of the paper material stream and the plastic material stream, and adjusting, a flow rate of paper into the paper material stream and a flow rate of plastic into the plastic material stream such that the calculated paper/plastic ratio of the combined stream equals a target paper/plastic ratio.