A process for cooling quench effluent includes providing a quench column effluent to a quench column aftercooler condensate; cooling the quench column effluent to provide a quench column aftercooler condensate; and recirculating at least a portion of the quench column aftercooler condensate to the quench column aftercooler at a rate to prevent fouling of the quench column aftercooler.

A sulfur adsorbent comprising boric acid deposited on an activated carbon support, and a method of separating at least a portion of sulfur compounds from a sulfur-containing mixture with the sulfur adsorbent. Various combinations of embodiments of the sulfur adsorbent and the method are also provided.

The invention relates to a process for separating off and/or recovering nitrogen compounds, in particular for separating off ammonia and/or recovering or producing nitrogen fertilizer, from a liquid or sludge substrate, in which a liquid or sludge substrate is introduced into a degassing vessel to which subatmospheric pressure is applied and ammonia gas formed is introduced by means of a vacuum pump into at least one scrubber which is located downstream of the degassing vessel and to which subatmospheric pressure is applied and into which acid is introduced, wherein the acid or an ammonium salt-containing liquid obtained in the at least one scrubber is taken off from the at least one scrubber, cooled and subsequently sprayed back into the at least one scrubber. The invention further relates to a plant for carrying out such a process.

Disclosed are methods and systems for removing submicron particles from a gas stream, in particular from urea prilling off-gas, wherein a Venturi ejector is used. A method comprises contacting a gas stream containing submicron particles in a Venturi ejector with an injected high velocity scrubbing liquid to provide a pumping action, wherein the scrubbing liquid has an initial velocity of at least 2 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h). The disclosure also pertains to a prilling tower having a gas stream treatment system comprising a Venturi ejector at the top of the prilling tower, and to a method of modifying an existing prilling tower.

A membrane humidifier assembly for fuel cell applications includes a first flow field plate adapted to facilitate flow of a first gas thereto, a second flow field plate adapted to facilitate flow of a second gas thereto, and a polymeric membrane disposed between the first flow field plate and second flow field plate. The polymeric membrane is adapted to permit transfer of water. In order to prevent a perfluorosulfonic acid polymer, humidifier membrane from fouling and having diminished water vapor transport performance, ammonia and cation contaminants must be removed from the ambient gas streams. Suitable cationic and ammonia scavengers include filters comprising polymers functionalized with carboxylic acid groups, phosphonic acid groups, sulfonic acid groups, perfluorosulfonic acid groups or combinations thereof.

Elemental mercury is removed from a gas by contacting it with a halogen dissolved in an organic solvent. The mercury accumulates in the organic solvent and can be removed by extraction with an aqueous solution with a complexing agent, by adsorption, and by combinations. The absorption process can also operate by use of a series of absorbers which have successively higher concentrations of halogen in the solution and which successively remove more the mercury from the gas. A portion of the solvent in the last absorber can be cascaded to the previous absorber in the series. In one embodiment, the process is carried out at a temperature of absorber at less than or equal to 28 C. above the higher of the water dew point and the hydrocarbon dew point. The mercury waste from the process is produced as either an aqueous solution or a small volume of mercuric sulfide.

A substrate processing apparatus includes a processing unit supplying at least one of a plurality of types of chemical liquids to a substrate and a scrubber cleaning an exhaust by bringing the exhaust in contact with a scrubbing liquid. The scrubber includes an exhaust passage that guides the exhaust, generated at the processing unit and containing the chemical liquid, toward an exhaust equipment disposed outside the substrate processing apparatus and a discharger that is able to discharge each of a plurality of types of scrubbing liquids that clean the exhaust individually inside the exhaust passage. A controller selects any one of the plurality of types of scrubbing liquids based on the type of chemical liquid contained in the exhaust and makes the selected scrubbing liquid be discharged from the discharger.

The invention relates to a process for the treatment of a gas stream comprising hydrochloric acid, hydrofluoric acid and fluorinated/oxygenated compounds, in which the gas stream is successively subjected to: a stage of catalytic hydrolysis; a stage of washing with an acid solution; a stage of adsorption of impurities by active charcoal; a stage of adiabatic or isothermal absorption of the hydrochloric acid in an aqueous solution, making it possible to collect hydrochloric acid solution.

A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of hypobromite is disclosed. The hypobromite is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses hypobromite in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

The invention relates to a process for the treatment of a gas stream comprising hydrochloric acid, hydrofluoric acid and fluorinated/oxygenated compounds, in which the gas stream is successively subjected to: a stage of catalytic hydrolysis; a stage of washing with an acid solution; a stage of adsorption of impurities by active charcoal; a stage of adiabatic or isothermal absorption of the hydrochloric acid in an aqueous solution, making it possible to collect hydrochloric acid solution.