A flue gas desulfurization unit is converted from operating with lime or magnesium enhanced lime under inhibited oxidation into a unit that operates using limestone under inhibited oxidation conditions. A ball mill grinding unit may be installed to crush the limestone thereby producing a suspended slurry of fine limestone particles which is pumped to the reaction vessel. When installed, the ball mill may be installed in the process immediately downstream of the existing slaking equipment. The suspended solution may be maintained at a pH in the range of 3.0 to 6.5, optimally at approximately 5.0 to increase the dissolution rate of the limestone reagent produced by the ball mill. The post-conversion process may also require the addition of organic acids and oxidation inhibitors to achieve better SO.sub.2 removal from the flue gas.

A flue gas treatment device is provided. A wet electrostatic precipitator and a flue gas heater are integrated in an integrated flue housing of the flue gas treatment device, thus the occupied area of the flue gas treatment device is smaller than that of the solution with devices being arranged separately. Furthermore, since a bidirectional transition flue is not required to be arranged in the integrated flue housing, the flue gas has a good flow uniformity, and further it is not required to arrange a flow equalization orifice plate in the flue, thus the flue gas has a small resistance, thereby reducing the power consumption of the draught fan and increasing the efficiency of the power plant.

The present disclosure relates to a wastewater flue evaporating device. An wastewater evaporation crystallizer is provided, including an evaporating tube inlet, an inlet flange, an inlet chamber, a pneumatic inlet baffle, an evaporating tube body, a pneumatic outlet baffle, an outlet chamber, an outlet flange, and an evaporating tube outlet which are successively coupled, where the evaporating tube inlet is connected to provide a gas pipeline; the gas pipeline is connected on a flue between an external denitration device and an air preheater; the evaporating tube outlet is communicated with an inlet flue of a dust collector; the evaporating tube body is provided with a wastewater nozzle; and the wastewater nozzle is communicated with a pretreated waste pipe. The present disclosure provides an efficient and energy-saving wastewater evaporation crystallizer which increases evaporation efficiency by bringing in a high-temperature gas at a front end of the air preheater.

A vertical scrubber (1) for exhaust gas from a marine vessel is described. An exhaust gas tube (2) is substantially coaxially arranged through the bottom of a lower scrubbing chamber (3) and is released though an exhaust gas outlet (20) being coaxially arranged through the top of an upper scrubbing chamber (13). A lower scrubbing chamber deflection body (4) is arranged above the opening of the exhaust gas tube (2) for redirecting the exhaust gas towards the walls of the scrubber and create turbulent gas flow, where one or more lower chamber water injector(s) (6, 6′) is (are) arranged above the lower scrubbing chamber deflection body (4), to introduce scrubbing water, and where a lower chamber exhaust gas outlet (12) is arranged at the top of the lower scrubbing chamber (3) as a coaxial constriction, for withdrawing the partly scrubbed exhaust gas from the first scrubbing chamber and introducing the gas into the upper scrubbing chamber (13).

Processes for the treatment of waste streams from the hydroconversion of heavy hydrocarbons containing additives and catalysts are described. At least one of the SHC pitch stream, SDA pitch stream, and the heavy residue stream is sent to a thermal oxidation system. The metals in the SHC and SDA pitch streams and the heavy residue stream are oxidized and can be easily recovered as clean powdered metal oxides which can be reused or sold. The processes produce chemicals which can be recovered and sold.

A process for the treatment of sulfidic spent caustic, conditioned catalyst regeneration vent gas, C4 isomerization off gas, various and hydrocarbon containing liquid and gaseous streams in addition to toxic containing streams like cyanidic off gas and waste water in a propane/butane dehydrogenation complex is described. Various effluent streams are combined in appropriate collection vessels, including an off-gas knockout drum, a hydrocarbon buffer vessel, a spent caustic buffer vessel, an optional a waste water buffer vessel, and a fuel gas knockout drum. Streams from these vessels are sent to a thermal oxidation system.

A process for the treatment of waste water, spent air, and hydrocarbon containing liquid and gaseous streams in the cumene/phenol complex is described. Various effluent streams are combined in appropriate collection vessels, including a spent air knockout drum, a hydrocarbon buffer vessel, a fuel gas knockout drum, a phenolic water vessel, and a non-phenolic water vessel. Streams from these vessels are sent to a thermal oxidation system.

A process for treating effluent streams in a renewable transportation fuel production process is described. One or more of the sour water stream and an acid gas stream are treated directly in thermal oxidation section. The process allows the elimination or size reduction of a sour water stripper unit, waste water treatment plant, and sulfur recovery unit.

To provide a method for predicting a deactivation phenomenon in a flue-gas desulfurization unit to prevent the occurrence of the deactivation phenomenon before it happens. There is provided a method for preventing the occurrence of a deactivation phenomenon in a flue-gas desulfurization unit that treats flue gas of a coal-fired boiler, the method includes calculating a deactivation potential as an index of the deactivation phenomenon based on alkaline components such as Na, Ca, Mg, and K contained in ash in the flue gas, and performing an operation management, such as adjustment of set value of a pH control system, on the flue-gas desulfurization unit depending on change of the deactivation potential.

A desulfurization gas process includes water vapor, CO.sub.2 and SO.sub.x (x=2 and/or 3). In a treatment unit, the gas contacts a cooled alkaline aqueous solution having a temperature lower than an initial gas temperature, water and a carbonate of an alkali metal, to cool the gas, condense some water vapor and absorb SO.sub.x in the carbonate-containing solution, produce an SO.sub.x-depleted gas and an acidic aqueous solution including sulfate and/or sulfite ions. The SO.sub.x-depleted gas and a portion of the acidic aqueous solution can then be withdrawn from the treatment unit. Carbonate of the alkali metal can be added to remaining acidic aqueous solution to obtain a made-up alkaline aqueous solution. This solution can be cooled and reused as the cooled alkaline aqueous solution. An SO.sub.x absorbent solution includes a bleed stream from a CO.sub.2-capture process, sodium or potassium carbonate, and an acidic aqueous solution obtained from desulfurization.