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THE TECHNOLOGY The intellectual property central to ENVI is the ENVI-clean™ Scrubber.This devise removes targeted gases and particulate matter from fluid streams. Unlike other wet scrubbers, which use sprays and water droplets, EnviroResolutions technology mixes the hot exhaust gas and liquid in a highly turbulent mixing zone to produce a fine bubble distribution between the hot gas and the scrubbing liquid. This creates an unusually high surface area of contact between the gas and liquid thereby enhancing osmotic transfer between the liquid and gas phases. This enables an effective transfer of particulate and targeted gaseous pollutants from the exhaust to the liquid at a significant cost saving. The ENVI-clean™ Scrubber itself was designed for simplicity, efficiency, economics, and adaptability. It targets the reduction of sulphur dioxide (SO2); oxides of nitrogen (NOX); unburned hydrocarbons, soot and ash (particulate). These pollutants cause acid rain, asthma, cancer, and a host of other illnesses that can result in death. The patented ENVI-clean™ Scrubber is designed to remove specified materials from both gaseous and liquid streams. The ENVI-clean™ system is a robust industrial unit that is designed to meet the continuous operating demands of industry. The Scrubber has application in removing polluting materials from:
Polluting materials can be solid particulate matter or chemical compounds such as sulphur oxides, nitrogen oxides, ammonia, VOC’s and industrial gases that may be corrosive or have unpleasant odors. In the first quarter of 2009 EnviroResolutions plans to test the Scrubber’s potential to remove heavy metals such as mercury from coal combustion exhaust. The ENVI-clean™ Scrubber is a wet scrubbing system that is based on the complete interaction of the polluted stream with a scrubbing solution. The target stream is passed through a scrubbing head that is submerged in scrubbing fluid. The stream is aggressively agitated upon exit of the scrubbing head to insure complete chemical and mechanical interaction of the scrubbing fluid and the polluted waste stream. There are no moving parts within the Scrubber and the material selection is intended to provide a long maintenance interval. Solid particulate matter and precipitated salts of targeted polluting compounds are separated from the scrubbing fluid by a continuous filtration system. The solid matter is collected in a filter or storage tank for disposal. Auxiliary systems maintain the fluid level and temperature in the Scrubber, and adjust the concentration of the neutralizing solution. These systems are monitored by a programmable logic controller (PLC) and operate on standard electrical and water services. Neutralizing chemicals for diesel and coal applications are commonly available from most chemical product suppliers. Operating Components of Diesel and Coal Combustion Exhaust Scrubbers Exhaust Cooling Unit The hot exhaust from diesel or coal combustion is cooled to less than 80 degrees C in an air-to-liquid exhaust cooling unit. The cooling unit can be remote from the Scrubber if space is constrained. The fluid used to cool the gas exits the unit and is piped to the Scrubber where it enters the Scrubber with the gas stream. Scrubber Tank The cooled gas and liquid enter the Scrubber and are routed to the scrubbing head. The head is submerged in scrubbing fluid and upon exit the gas creates a turbulent agitation of the fluid that insures complete contact. The backpressure in the system is designed to be below 15 inches of water. The temperature is monitored and maintained in a target range of 50 to 80 degrees C. The targeted compounds are SO2 and NOx. The SO2 is chemically removed with the sulphur being isolated as a salt compound. The ash, soot and unburned hydrocarbons are mechanically removed by the turbulent agitation of the gas. They are captured in the scrubbing solution while the balance of the gas stream rises through the scrubbing fluid and exits the scrubbing tank. Water Separation from the Exhaust Gas Upon exit from the Scrubber, the exhaust gas passes through a water separation device to remove the free water in the exhaust stream. Reheating of the Exhaust Stream – Coal Applications In order to provide the vertical lift in coal exhaust chimneys, the exhaust gas is routed to an air-to-air heat exchanger prior to returning to the stack.
Auxiliary Systems Scrubbing Fluid Cooling and Filtration The scrubbing fluid is continuously circulated through filtration/separation and heat exchange devices to remove the solid particulate and maintain temperature within the target range. Pumps are used for the circulation. The cooled fluid from the heat exchanger completes its circulation path by entering the exhaust cooling unit where it is used to cool the incoming gas. Depending on the application, the scrubbing fluid will be passed through a filter or routed to a centrifuge to remove the solid matter from the fluid. In the case of a filter, the solids will be collected in the filter element which will be removed in a scheduled maintenance cycle. Continuous operation is maintained by having two filters in parallel. When a centrifuge is used, the fluid is constantly circulated through the unit and the solids will be piped to a holding tank for collection and disposal. Makeup Water The temperature and operating characteristics of the Scrubber require the addition of water to the scrubbing tank. The rate of water loss is related to the volume and temperature of the gas being scrubbed. Sizing of the makeup water tank is proportional to the volume of exhaust gas to be scrubbed. The scrubber fluid level is monitored by the PLC and water is pumped into the scrubber tank as required. Neutralizing Solution A solution to neutralize the build up of acid in the scrubbing tank is added to the makeup water. The target is to maintain the scrubbing fluid in a slightly alkaline state. This is to insure that the exhaust gas from the Scrubber has no acid effects on the environment. The neutralizing solution will also contain the chemistry required to cause the targeted pollutants to be precipitated in the form of a salt compound to be captured in the filtration/separation system.
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