291 results about "Gaseous ammonia" patented technology

The present invention provides novel methods for removal and disposal of ammonia from spent dialysate in a dialysis system. Ammonium ions present in spent dialysate are converted into gaseous ammonia by raising the pH of the spent dialysate solution in a first reactor. Gaseous ammonia diffuses through a semi-permeable hydrophobic membrane at the outlet of the first reactor and into a second reactor via a gas channel. The second reactor converts gaseous ammonia into an ammonium compound for easy disposal.

An exhaust system includes a first SCR catalyst and a second SCR catalyst positioned downstream of the first SCR catalyst. A first injector is provided upstream of the first SCR catalyst, and a second injector is provided upstream of the second SCR catalyst. The exhaust system further includes a gaseous ammonia supply device fluidly connected to the first injector for supplying gaseous ammonia to the exhaust gas by the first injector, and an ammonia-containing reductant reservoir fluidly connected to the second injector for supplying a fluid ammonia-containing reductant, such as urea, to the exhaust gas by the second injector. The first SCR catalyst has a smaller volume than the second SCR catalyst for a fast warm-up of the first SCR catalyst.

A reusable device for continuously monitoring gaseous ammonia concentration in a surrounding environment comprising a plurality of layers, including an active layer in which a dye (e.g., an indicator dye useful for measurement of pH) is immobilized to a membrane (e.g., polyamide membrane), and a hydrophobic filter layer capable of permitting contact between the active membrane and dissolved gaseous ammonia.

Hydrogen fluoride undercut of oxide layers may be reduced by using a low pressure mixture of gaseous hydrogen fluoride and gaseous ammonia mixture. Organic photoresists can be used as a masking material when using the gaseous hydrogen fluoride/ammonia mixture without resulting in an enhanced reaction rate. In addition, because of the reaction conditions, the dimensions in the oxide layer being etched can be specifically sized smaller than openings made in the overcoating masking material.

A method for chemically modifying a tobacco material during a curing process involves treating the tobacco material in a curing enclosure at a temperature and for a time sufficient to produce cured tobacco. The method also involves contacting the tobacco material with a chemical reagent before and/or during the time period that the tobacco material is cured so that the chemical reagent can interact with the tobacco material, thus resulting in further change in the chemical nature of the cured tobacco material. An exemplary chemical reagent is an ammonia source, which can be applied to a tobacco material in a variety of ways, including by spraying an aqueous ammonia source onto the tobacco or by introducing gaseous ammonia into the curing enclosure during the curing process.

A method for removing hydrogen sulphide and carbon dioxide from a gas stream includes the step of contacting the gas stream with aqueous and gaseous ammonia in a closed vessel in the presence of solid iron. An apparatus for removing hydrogen sulphide and carbon dioxide from a gas stream includes a closed vessel for containing aqueous and gaseous ammonia and an iron source. The vessel is partitioned into inlet and outlet chambers and may itself serve as the iron source.

A method for controlling a selective catalytic reduction catalyst in an exhaust line of an internal combustion engine is disclosed, wherein the supply of a quantity of a gaseous ammonia reductant to the SCR catalyst uses a closed-loop SCR catalyst model coupled to a SCR-out NOx sensor that measures a SCR-out NOx emission value. The closed-loop SCR catalyst model uses a relationship linking the measured SCR-out NOx value to the NOx conversion efficiency and the ammonia slip. The actual NH₃ emission value and/or an actual SCR-out NOx indicative value are computed based upon differentiation of said relationship.

A process to provide a pressurized gas stream useful for removing nitrogen oxides from a combustion gas stream by hydrolyzing urea in aqueous solution in a closed reactor to evolve gaseous ammonia at a rate essentially balanced to the amount required from the combustion gas stream. The improvement resides in maintaining the pressure in the reactor within a preselected range when the demand for ammonia for external use suddenly drops by cooling the solution within the hydrolysis reactor by heat exchange either within or external to the reactor in response to rapid changes in demand for ammonia required to remove said nitrogen oxides.

An integrated supply method by using ammonia water as a desulphurization and denitration reactant contains the following steps of: 1) ammonia water evaporation: part of ammonia in inputted concentrated ammonia water is evaporated by controlling the temperature and pressure of an evaporator and other components are remained in the ammonia water; 2) gaseous ammonia storage and its use for denitration: a buffer tank is configured to store the gaseous ammonia generated from the ammonia water evaporation under a certain pressure so as to supply ammonia for a denitration apparatus and stabilize the operation of the evaporator; and 3) dilute ammonia water storage and its use for desulphurization: a dilute ammonia water groove is correspondingly configured to store the ammonia water, the concentration of which is reduced after the original ammonia water is evaporated into the gaseous ammonia, and the dilute ammonia water is used for flue gas desulphurization. The operation pressure and concentration of the evaporator are stabilized by extraction of the dilute ammonia water from the evaporator, and simultaneously ammonia water is stably supplied for the flue gas desulphurization apparatus. The inputted concentrated ammonia water is stored in a concentrated ammonia water groove and enters into the evaporator from the concentrated ammonia water groove. Ammonia is evaporated into a gas phase after being heated by a heater of the evaporator. The gaseous ammonia is used for denitration and the dilute ammonia water is used for desulphurization.

A system for storage and dosing of ammonia, including a solid ammonia storage material capable of binding and releasing ammonia reversibly by adsorption/absorption. The system is able to release ammonia gradually according to a demand that can vary over time with intermediate periods of no ammonia demand. A main storage unit and a start-up storage unit are provided. The storage units hold ammonia storage material. At least one one-way valve is provided via which the one main storage unit is in communication with the start-up storage unit. The one-way valve prevents any back-flow of ammonia from the start-up storage unit to the main storage unit. Heating devices are arranged to heat the main storage unit and the start-up storage unit separately to generate gaseous ammonia by thermal desorption from the solid storage material. A controller controls the heating power of the main storage unit and the start-up storage unit, thereby enabling ammonia release from at least one of the start-up and/or the main storage unit. A dosing valve controls ammonia flow from the storage units according to a demand.

A mixing device and method for a diesel exhaust system is disclosed having a chamber, a mixer within the chamber, and an injection tube supported on the mixer within the chamber. The mixer is positioned within the chamber adjacent an inlet and includes a plurality of angled blades to effect turbulent flow in a diesel exhaust stream entering the chamber through the inlet. The injection tube includes a plurality of injection points (e.g., openings) for discharging a reagent, such as gaseous ammonia (NH₃), into the exhaust stream. The injection tube is curved, and more specifically it is coiled with the injection points spread along the length of the tube in order to deliver reagent across a section of the chamber perpendicular to the exhaust stream flow.

A process is provided for the removal of hydrogen sulfide out of a gaseous stream (22), such as a natural gas, by contacting the hydrogen sulfide containing gas with a sorbing liquid (26) containing a tertiary amine so that the hydrogen sulfide is sorbed into the liquid in absorber (11) and transferring the sorbing liquid/hydrogen sulfide mixture to a reactor (15) where the tertiary amine promotes the conversion of the hydrogen sulfide into polysulfide via reaction with sulfur; transferring the polysulfide solution from the reactor (15) to a regenerator (10) where polysulfide is converted into elemental sulfur via reaction with air (9); transferring at least a portion of the solution (25) containing elemental sulfur, as well as sulfate and thiosulfate species, into a mixture (36) where it is contacted with gaseous ammonia which reacts with the sulfate and thiosulfate species to produce ammonium sulfate and ammonium thiosulfate which are removed from the solution while the remaining portion of solution (25) is transferred to a sulfur recovery unit (14). That portion of the solution which has been subjected to ammonium sulfate and ammonium thiosulfate removal is rejoined with that portion of the solution (25) being forwarded to sulfur recovery unit (14). The solution from the sulfur recovery unit (14) is recycled back to the absorber (11).

The production process of NO gas for synthesizing oxalate belongs to the field of chemical and environment protection technology. The production process includes ammoxidation of air to produce NOx as the NO gas for synthesizing oxalate, or utilizing the NOx in nitric acid producing tail gas as the NO gas for synthesizing oxalate, absorbing nitrite with alcohols and compression and condensation to recover alcohols and nitrite from the tail gas. The production process has liquid ammonia or gaseous ammonia of concentration 1-30 vol%, oxygen of concentration 1-30 vol%, alcohol concentration of 50-100 wt%, pressure of 0.1-10 MPa, and condensation temperature of ¿C20 to 100 deg.c. The present invention has high economic utility and social utility.

The invention discloses a method for producing monoammonium phosphate and coproducing an N-P binary compound fertilizer by using wet-process phosphoric acid. According to the method, wet-process phosphoric acid prepared from low-grade phosphate ores is used as a raw material. The method comprises the following steps: concentrating and setting the wet-process phosphoric acid to remove impurities; diluting with process water; neutralizing with ammonia twice; filtering twice; concentrating; cooling for crystallization; centrifugally separating; drying to obtain the industrial grade monoammonium phosphate finished product; and mixing acid sludge, the centrifugalized mother liquor, residue and the flushing fluid in a slurry mixing tank, performing spray drying to obtain the N-P binary compound fertilizer. According to the method, wet-process phosphoric acid and gaseous ammonia are directly used as raw materials and the existing related devices in the phosphoric acid industry and resources such as waste heat steam and self power can be utilized, thus the yield of industrial grade monoammonium phosphate can be increased, the output of the byproduct N-P binary compound fertilizer can be reduced, the production cost of industrial grade monoammonium phosphate can be greatly reduced, the industry scale can be enlarged, the adaptability of the equipment can be enhanced, the market demands can be met, the stepped comprehensive utilization of the phosphorus resource can be realized and the economic benefit is higher.

The present invention relates to a process for treating a wastewater comprising an ammonium ion species and a phosphorus ion species. The process comprises the steps of: (i) treating the effluent in a first stage of the process to convert the phosphorus to a phosphorus-containing salt; (ii) treating the wastewater in a second stage of the process to convert the ammonium ion species to gaseous ammonia; (iii) removing the struvite and/or other phosphorous containing salts from the effluent; and (iv) removing the gaseous ammonia from the wastewater.

Liquid ammonia is fed from an ammonia storage tank to a vaporizer where it is vaporized. Gaseous ammonia vaporized inside the vaporizer is on the one hand injected from an ammonia injector and on the other hand reformed by a reformer, then injected from a reformed gas injector. The amount of liquid ammonia fed into the vaporizer is made to become equal to the amount of ammonia fed into the combustion chamber in the form of gaseous fuel by control of the amount of feed of the liquid ammonia to the vaporizer.

An ammonia purification system includes a hydrocarbon removal station that removes hydrocarbons from gaseous ammonia via adsorption, a moisture removal station that removes water from gaseous ammonia via adsorption, and a distillation station including a distillation column connected with a condenser to facilitate removal of impurities from ammonia and condensation of gaseous ammonia to form a purified liquid ammonia product. The system further includes a storage tank to receive purified ammonia, a remote station connected with the storage tank, and a vaporizer connected with the storage tank. The vaporizer is configured to receive and vaporize liquid ammonia from the storage tank and deliver gaseous ammonia back to the storage tank so as to facilitate pumping of the ammonia to the remote station based upon a vapor pressure established within the storage tank.

The invention belongs to the technical field of sewage processing, and discloses a device and method for removing and recycling ammonia nitrogen in sewage by means of a microbial fuel cell. A double-chamber microbial fuel cell system and an ammonia recycling device are built, an anode chamber is inoculated with domesticated electrogenesis mixed bacterium liquid, sodium acetate is added to serve as electron donors, and then phosphate buffered solutions with a PH value of 7.0 and nutrient solutions are added to the anode chamber until the anode chamber is full; the sewage containing the ammonia nitrogen is added to a cathode chamber, and air is led to the cathode chamber through an aeration device; H2SO4 of 0.1 mol*L<-1> is added to an ammonia recycling device, then the microbial fuel cell is started, and the ammonia nitrogen in the cathode chamber is converted into gaseous ammonia, removed from the sewage and recycled by the ammonia recycling device. The device and method are used for removing and recycling the ammonia nitrogen in the sewage and have good economic efficiency and environmental protection benefits.

The invention provides a method for recycling ammonia during the production of ammonium paratungstate. During the evaporation and crystallization of a solution for producing the ammonium paratungstate, free ammonia in the solution and ammonia released by the crystallization process can be volatilized in a gas state. Firstly, a closed vessel is used to collect gaseous ammonia; secondly, the ammonia is reclaimed through the mode of condensation and separation; and finally the reclaimed ammonia can be returned to the main production process and be used for preparing a strippant. The method reduces the consumption of liquid ammonia during the production of the ammonium paratungstate, thereby greatly reducing the production cost and having an ammonia reclamation rate of above 90 percent. Simultaneously, the method prevents the air pollution caused by a large amount of evaporated and overflowed ammonia gas; and the atmospheric emission reaches national standards. Therefore, the method reduces the corrosion of workshop equipment and realizes the reclamation of the ammonia, thereby not only realizing considerable economic benefits, but also realizing certain social and environmental benefits.

A method for saturating or re-saturating ammonia storage material (1) capable of reversibly absorbing and desorbing ammonia in one or more storage containers (2), wherein said material is partly or fully depleted of ammonia, with ammonia to a predetermined saturation degree comprises a. placing the storage container(s) (2) in direct or indirect contact with a thermostatting medium (4) at a temperature level T_T≦ about 65° C.; and b. connecting the storage container(s) (2) to a source of gaseous ammonia wherein at least during a part of the method the gaseous ammonia during saturating or re-saturation of the ammonia storage material (1) is at a pressure P_S≦ about P_T, wherein P_S is the ammonia pressure during saturating or re-saturating of the ammonia storage material (1) and P_T is the equilibrium vapor pressure of liquid ammonia at the temperature level T_T.