(560fh) An Experimental Verification of Pressure Drop for Removal of VOC

New trends in the design of individual pieces of equipment in chemical plants include a gradual decrease discharges of pollutants and investment and operating costs together with an increase in the overall effectiveness of the plant. For the proper and reliable design of such integrated multifunctional apparatuses, it is necessary to have a suitable and experimentally verified calculation tools for their design and analysis. Our work is focused on experimental acquisition of pressure drop data a obtaining mathematical dependencies of catalyst pressure losses for flue gas emission cleaning equipment. This paper presents the results of the first stage of our experimental verification focused on the analysis of the selected type catalysts for removal VOC (Volatile organic compounds) from a hydraulic characteristic point of view.

Organic Compounds (VOCs) are considered harmful on their own due to their negative respiratory, carcinogenic, neurological or other effects. Industrial waste gases contain many different organic substances. For this reason, industrial waste gases are purified that contains VOCs before are released to the atmosphere. Legislation sets and monitors VOC emission limits in most countries around the world. The photochemical reaction of VOCs with NOx creates harmful compounds that can lead to adverse effects of climate and public health.

The removal of VOC pollutants is accomplished by several possible technological processes. High VOC concentrations and large flow rates are commonly disposed of by thermal oxidation, eg in the chemical industry. This is burning the organic vapours with natural gas in the combustion chambers. In many cases of the industrial off gas treatment containing VOC is possible to change the technology from thermal oxidation into catalytic oxidation and reduce operating costs in terms of difference in the savings because the reduced natural gas consumption and the price of used catalyst.

There are many types of ceramic catalyst carriers, from the most well-known HoneyComb type honeycomb structures to various bulk beds such as Pall, Lessing or Raschig rings, various saddles such as Berl or Intalox, Interpack bodies, or spheres. All these catalyst supports produce a significant pressure loss in the process. Flue gas or propulsion fan creates a pressure drop to overcome resistance in pipes and equipment. These resistances are generated by friction or local and filling (catalyzers). Pressure losses need to be minimized and optimized from an energy and thus economic point of view. For this purpose, it is also necessary to perfectly describe pressure losses by mathematical equations. There are several mathematical equations and methods for calculating pressure losses for different types of catalyst supports that need to be verified by data obtained by experimental measurement.

Measurements of some types of materials forming the regenerative or catalitic bed were performed for different fluid flow rates (air) in range of 7 - 50 m³/h. The pressure drops are introduced for packed bed formed by ball particles of various diameters and honeycomp of various grid. To measure the pressure drop we used the test apparatus located in our institute described. This equipment allows the results of measured pressure drops to be automatically stored in the PC. The material which formed the bed was placed on a sieve inside a square 150x150 mm tube. The height of the bed was different for various diameters and was designed to cover as much as possible the measuring range of the differential pressure sensor. The pressure drop of the sieve was also determined and subsequently subtracted from the total measured pressure drop of the bed.

For the purpose of verification of feasibility in industrial case studies with catalyst and catalyst testing, the modular design pilot plant was proposed and implemented. This unit is scalable and can be used to test the sprinkled catalysts and catalysts in form of the monoliths both in lab or real industrial conditions. This unit is primarily intended to remove nitrogen oxides from the flue gas, and accurate measurement in the reactor allows measurement of the pressure loss of various catalysts.