Envirocare International Inc.

Other

Bha Group Holdings, Inc.

Process and Control Technology Corporation

Preciptech, Inc.

Environmental Quality Management, Inc.

James J Schwab

Ronald L Hawks

Marlin H Anderson, Jr

Jim Parsons

Joseph R Riley

A method and apparatus for controlling emissions of acid forming gases such as sulfur dioxide from cement plants is disclosed. Gaseous effluent from the cement plant pyroprocessing chamber is routed to the plant's raw mill to heat and dry the feed meal used in cement production. When the raw mill is in operation microfine lime particles are sprayed into the raw mill using a nozzle system. The spraying of hydrated lime into the raw mill scrubs acid forming gases in the process gaseous effluent. When the raw mill is not operational, microfine lime is sprayed into a gas conditioning tower that is also used to reduce the temperature of the effluent gases to facilitate efficient collection of dust particles prior to emission of the cleansed effluent flow into the atmosphere.

Method and apparatus for controlling acid gas emissions from cement plants

A method and apparatus for reducing discharges into the atmosphere of mercury pollutants associated with dry process, precalciner cement manufacturing is shown. Raw feed meal used in cement production is heated in a special heating chamber to drive off volatile mercury pollutants, such as elemental mercury and mercury oxides. Preferably, the feed meal is heated to a temperature of at least 175&#xb0; C. The gases that are driven off flow are then cooled to condense the mercury pollutants causing them to be adsorbed on carbon particles injected into the gas flow. The carbon particles containing the condensed mercury pollutants are then filtered out of gas flow, for example, using a fabric filter. The gas flow may be burned to destroy other volatile pollutants such as hydrocarbons and/or ammonia.

Apparatus and method for controlling mercury pollution from a cement plant

A method and apparatus for reducing air pollutants associated with dry process, precalciner cement manufacturing is shown. Raw feed meal used in cement production is heated in a special heating chamber to drive off volatile compounds, such as organic materials and salts of ammonia. Preferably, the feed meal is heated to a temperature of at least 350&#xb0; F. The gases that are driven off flow to the precalciner where they are combusted and rendered harmless. Heat is provided by diverting at least a portion of the exhaust gases from the cement pyroprocessing kiln to the special heater. The raw feed meal is indirectly heated using a heat exchange wall between the feed meal and the kiln exhaust gas flow. In addition, a base-containing material such as lime or precalcined feed meal, may be added to the raw feed before treatment meal to promote the breakdown of inorganic ammonium compounds, thereby releasing gaseous ammonia which is also destroyed upon subsequent combustion. Hot precalcined meal may also be used to provide some of the heat required to heat the raw feed meal in the special heating chamber.

Apparatus for controlling pollution from a cement plant

A method and apparatus for reducing air pollutants associated with dry process, precalciner cement manufacturing is shown. Raw feed meal used in cement production is heated in a special heating chamber to drive off volatile compounds, such as organic materials and salts of ammonia. Preferably, the feed meal is heated to a temperature of at least 350&#xb0; F. The gases that are driven off flow to the precalciner where they are combusted and rendered harmless. Heat is provided by diverting at least a portion of the exhaust gases from the cement pyroprocessing kiln to the special heater. The raw feed meal is indirectly heated using a heat exchange wall between the feed meal and the kiln exhaust gas flow. In addition, abase-containing material such as lime or precalcined feed meal, may be added to the raw feed before treatment meal to promote the breakdown of inorganic ammonium compounds, thereby releasing gaseous ammonia which is also destroyed upon subsequent combustion. Hot precalcined meal may also be used to provide some of the heat required to heat the raw feed meal in the special heating chamber.

Method and apparatus for controlling pollution from a cement plant

A low-energy venturi pre-scrubber optimized for removing abrasive particles from a gaseous effluent is disclosed. While venturi scrubbers are efficiently used for at removing entrained particulates in air pollution control systems, they can be damaged due to the abrasive characteristics of entrained particles, such as silica particles greater than a micrometer in diameter. According to the present invention, high scrubbing efficiencies can be obtained in equipment that is not damaged by the abrasive particles by first removing the abrasive particles in a low-energy venturi, and then removing the remaining particles in a second scrubber. In addition to improving the lifetime and reducing the maintenance costs of the venturi, scrubbing fluids have fewer large particles, allowing their use in downstream components, such as evaporative coolers.

Low-energy venturi pre-scrubber for an air pollution control system and method

The liquid cooling spray in a gas conditioning chamber is modified by the addition of an alkali to scrub sulfuir dioxide and other acid forming gases and a separation unit to remove particles that may contain either unreacted alkali or salts of the acid forming gases. A slurry of fine particles of hydrated lime is injected into the liquid coolant under conditions that result in kernels of controllable size that contain the alkali or salts from reactions with the acid forming gases. The modified cooling liquid provides for a high sulfur dioxide collection efficiency at a low molar ratio of alkali to sulfur, while the specified kernel size range allows fbr efficient removal of the kernels from the gas.

Chloride/sulfate removal system

The present invention provides improved systems and methods for scrubbing gas with a venturi scrubber. A dual spray venturi scrubber, in which a scrubbing liquid is injected upstream and counter to the flow through the venturi, provides for improved scrubbing performance, including efficient and economical scrubbing of fine particles. Specifically, the present invention reduces the scrubbing liquid pumping requirements, improves the scrubber performance, and provides better control of the pressure drop across the venturi scrubber. The control of pressure drop across the venturi can be obtained with no internal mechanisms or upstream spray.

Venturi and methods for particulate removal with counterflow sprays

A pollution control apparatus and method to scrub sulfur dioxide uses a lime slurry consisting of small diameter hydrated lime particles injected into the cooling water of a gas cooling tower. The diameter of the lime slurry particles is selected to be less than about 25 microns so that the lime particles substantially dissolve during the evaporative lifetime of the spray droplets. A preferred embodiment of the pollution control apparatus uses an in-line wet grinder and classifier to produce slurry as required.

Sulfur dioxide abatement method

A venturi scrubber for cleansing a contaminated gas flow is disclosed. An optimized spray of liquid droplets are injected into the gas flow from one or more nozzles positioned within the throat of each venturi element. The spray is injected counter to the direction of gas flow to increase interactions between contaminant particles and spray droplets. Preferably, hydraulic nozzles are used which emit a hollow cone spray. The spray droplets are preferably in the range of 40-200 microns mean mass diameter (MMD).

Venturi scrubber with optimized counterflow spray

A compact inlet system for redirecting the flow of gas to a gas treatment apparatus is shown. The inlet system is used to redirect a high volume flow of gas, such as the effluent from an industrial process, by as much as 180&deg; while introducing the gas flow uniformly into the treatment apparatus. The inlet system has a divergent transition section to slow the gas flow, a gas turning section to redirect the gas flow by 90&deg;, and a gas inlet chamber which redirects the gas flow by an additional 90&deg;, while at the same time introducing the gas flow uniformly into a treatment apparatus, such as a gas conditioning tower (GCT). The compact gas inlet chamber of the present invention has an elongate entrance, a circular outlet and a tapered midsection. When used with a GCT the greater uniformity provided by the present invention allows spray nozzles to be positioned within the throat of the entrance venturi of the GCT.

Tapered gas inlet for gas treatment system

A two-fluid atomizing nozzle incorporating a novel nozzle cap is described. The nozzle cap comprises support spokes which couple a pintle to the outer frame of the nozzle cap for holding the pintle in position. The support spokes comprise dams which prevent liquid from flowing along the length of the support spokes to the outer frame of the nozzle cap. This improves atomization by causing any liquid which flows along the spokes to reenter the high disturbance region of the nozzle. Additionally, it reduces erosion of the support spokes, particularly near the end of the spokes adjacent to the outer frame of the nozzle cap. Moreover, it reduces erosion of the interior wall of the outer frame of the nozzle cap. In another embodiment the support spokes have a non-planar inlet surface to improve atomization and to reduce erosion of the support spokes and the interior wall of the outer frame.

Atomizing nozzle

A method is provided for abating acidic contaminants, such as sulfur dioxide and hydrogen chloride, in exhaust gases while minimizing the formation of visible plumes of ammonium salts proximate to the outlet of the exhaust stack by injecting a spray of an alkaline liquid, such as sodium hydroxide or potassium hydroxide, into the contaminated exhaust gases wherein the pH of the alkaline liquid is high enough, i.e. greater than a pH of about 11, so that the acidic contaminants preferentially react with the alkaline liquid rather than the ammonia in the gases, thereby minimizing formation of visible plumes of ammonium salts.

Detached plume abatement method

An air pollution control system using a novel control system is disclosed. The control system is particularly useful with a gas conditioning tower ('GCT') which uses a spray from a two-fluid nozzle to cool hot process gases prior to flowing to an electrostatic precipitator. A first control loop, employing, for example, a temperature feedback control system, is used during normal operation of the system, and an override control loop is used to protect the electrostatic precipitator from overheated gases which may be diverted in the case of a plant upset. The override control loop adjusts the spray based on a calculation of the spray characteristics needed to meet the new GCT conditioning requirements. In another aspect the present invention relates to a method and apparatus for optmizing the spray from a two-fluid nozzle used in a GCT. In particular, the spray droplets are made larger when possible, thereby reducing the energy usage of the system. In yet another aspect of the present invention, the controller used in the air pollution control system directly regulates delivery pressure of the air compressor used as a source of compressed air for the two-fluid nozzle, for further energy savings.

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Napa, CA, United States of America

James J Schwab