MEASUREMENT OF SELECTED PRINCIPAL ORGANIC HAZARDOUS CONSTITUENT (POHC) IN CEMENT KILN

Transcription

1 J.Tek.Ling Edisi. Khusus Hal Jakarta, Juli ISSN x MEASUREMENT OF SELECTED PRINCIPAL ORGANIC HAZARDOUS CONSTITUENT (POHC) IN CEMENT KILN Kardono. Center of Environmental Technology Agency for the Assessment and Application of Technology (BPPT) Abstract: This paper presents the measurement of a selected principal organic hazardous constituent (POHC) injected into cement kiln that burned waste derived synthetic fuel. The POHC selected for the test was tetrachloroethane (more commonly known as perchloroethylene, or just PERC). The conditions of the kiln tested were maintained at its normal operation.the results will be used to calculate a destruction and removal efficiency (DRE) capability of that cement kiln. Thus, the test was assumed to be able to simulate the performance of a cement kiln acting as a waste combustor in destructing toxic waste. The test protocol was based upon the full set of procedures mandated by United States Environmental Protection Agency (USEPA) designed to demonstrate sufficient destruction of organic constituents, by demonstrating a % DRE. It was found that all measurement data of POHC resulted DRE values higher than the limit of %. As a conclusion, the cement kiln test has demonstrated the capability for achieving performance required for incineration of organic constituents. Keywords: POHC, PERC, waste derived synthetic fuel, kiln. 1. INTRODUCTION 1.1. Background monoxide and some cases total hydrocarbon concentrations in stack gas (EPA 1992). When the combustion of hazardous waste is operated, it must meet certain air permit conditions. Boiler industrial furnaces (BIFs) including cement kiln, can act as a combustor to destroy the hazardous waste derived synthetic fuel in its operation since it works at a very high temperature. The destruction of organic emissions from a cement kiln can be known by measuring a selected spike of the Principal Organic Hazardous Constituent (POHC) that is introduced into kiln and mixed with the fuel, in addition to by limiting carbon In this test therefore preparing hazardous waste and spiked POHC is a vital work that has first to be done. Blending of synthetic fuel, a mixing between organic wastes and waste oils and other components in a high shear mixer with nitrogen blanket, was conducted in a place. Each batch was controlled in such a way that the impacts on the environment and on cement quality were minimum. Parameters to be controlled included flash point, viscosity, free water content, specific gravity, ph, ash content, calorific value, organic 44

2 fluorine and organic chlorine content, total organic halide, total sulfur, and metal species. More stringent quality control was paid on the waste constituents as to minimize interferences on test burn measurements due to waste matrix. Consequently, organic wastes containing organic halides and metal compounds were avoided from the batch preparation. In this test, three spiked synthetic fuel batches were prepared, i.e. tetrachloroethylene spiked batch. Prior to spiked batch preparation, calculation was performed as to determine the final concentrations of spiking materials in the batches. The concentrations were governed by the gas flow rate, feeding rate, conditioning time, sampling time, absorbent capacity and detection limit of analytical method. A suitable POHC must be selected in order to demonstrate its destruction. The selection of POHC involved ranking organic compounds that are listed as Hazardous Organic Compound (HOC) in the US EPA s regulations (40 CFR Part 261, Appendix VIII), in terms of their relative difficulty of destruction. Two methods for ranking hazardous organic compounds as POHC are the heat of combustion index method and the thermal stability at low oxygen index method. The heat of combustion index method for ranking HOC as POHC is based on equilibrium theory which claims that the primary concern in evaluating the difficulty of destruction for a constituent is the amount of energy necessary to complete the combustion process. The heat of combustion index assumes that compounds that have low heat of combustion values are less able to support combustion than compounds that have high heat of combustion values. Perchloroethylene (PERC) has such an extremely low heat of combustion value that represents a conservative choice. Further, PERC is a volatile organic compound. The thermal stability index method for ranking HOCs as POHCs is based on gas-phase thermal stability at low oxygen condition, with the most stable constituents considered to be the most difficult to destroy. The list of 40 CFR Part 261, Appendix VIII HOCs is divided into seven classes. Generally, class 1 compounds are candidates for POHCs as they are the most difficult to destroy. However, most of the class 1 HOCs are not good candidates for POHCs. Some are not recommended as POHCs because they are common products of incomplete combustion making them difficult to accurately determine the destruction. For example, polynuclear aromatic compounds are generally difficult to obtain in sufficient amounts for spiking, and aliphatic compound, such as acetonitrile, are difficult to handle and present safety concern. PERC is a class 2 compound that is relatively easy to handle, readily available, and does not pose a compatibility problem with the other compounds present in the wastes. In addition, PERC is one of the highest ranked of the class 2 compounds that complied to all the selection criteria describe above. Since PCBs are not ranked in the Thermal Stability Index List, it is impossible to compare to tetrachloroethylene s ranking. Considering the fact that the di-, tri-, and tetrachlorodibenzo-p-dioxins are also ranked as class 2 compounds and listed lower than PERC, selection of tetrachloroethylene as the POHC based on the thermal stability index is a suitable choice. In addition to the two rankings, the following practical constraints need to be considered in the selection of POHCs for trial burn DESTRUCTION testing. Measurement Of Selected.J. Tek. Ling. PTL-BPPT. Edisi Khusus:

3 Be measurable by reliable and conventional techniques; Be compatible with the operation of the facility; Not be product of incomplete combustions (PICs) of the fuel, the waste, or other POHCs; Be capable of feeding and metering; Be safe to handle, and Be available in quantity at reasonable cost. During each test period, integrated samples of the stack gases were collected by the method detection limit for the POHC. The actual calculation of this PERC is done and resulted about 1050 kg/h of PERC or a total of 16.8 Tons PERC in a 16 hour operation. destruction of organic constituents, by demonstrating a % destruction of a selected principal organic hazardous constituent (POHC), which is selected to demonstrate a complete destruction of Polychlorinated Biphenyls (PCBs). 2. METHODOLOGY 2.1. Location The testing measurement was conducted at P.T. Semen Cibinong s Kiln NG# 2, located at Jl. Raya Narogong Desa Nambo, Cileungsi, Bogor, West Java Indonesia Sampling and Analysis Site Facilities The air pollution control (APC) equipment for the kiln is a three-stage electrostatic precipitator (ESP). Combustion gases from pre-heater/ kiln enter ESP via conditioning tower, which used evaporated moisture as conditioning material. The cleaned combustion gases enter an induced fan that exhausts to a stack. Figure 1. Volatile Organic Sampling Train (Method 30-UAEPA) 1.2. Research Objective The test was aimed to demonstrate compliance with Government regulation (PP) Number 85/1999 Hazardous Waste Treatment, and KEP- 03/BAPEDAL/09/1995 Technical Requirements for Hazardous and Toxic Waste Treatment. The test had to follow general requirements established by BAPEDAL for the testing of hazardous waste destruction facilities. The test protocol was based upon the full set of procedures mandated by BAPEDAL designed to demonstrate sufficient After existing the kiln, combustion gases enter into the suspension preheater and then enter the ESP. The ESP consists of one chamber with three fields. The emitted gases were exhausted through a stainless steel stack. Based on all above criteria, the POHC proposed as a spike was tetrachloroethylene (more commonly known as perchloroethylene) and also abbreviated as PERC. The target feed rate for PERC was developed by evaluating the method detection limits for the volatile organic stack sampling train (VOST train) and the minimum destruction ( %). 46

4 The input rate of PERC was calculated by the following equations: where ( Win Wout) DRE = x100..(1) W DRE : Destruction and Removal Efficiency (%) W in : POHC feed rate to the kiln burner (kg/h) : POHC emission rate from the stack (kg/h) W out For a DRE of % and the emission rate based on the method detection limit, the feed rate of the POHC material can be calculated as follows: in Wout W in =.. (2) The trial burn had to follow general requirements established by Environmental Ministry for the testing of hazardous waste destruction facilities that is to demonstrate sufficient destruction of organic constituents, by demonstrating a % destruction removal efficiency of a selected principal organic hazardous constituent (POHC). PERC used has a 99.5% concentration, which was mixed with 2 Tons pe hour of synthetic fuel resulting final concentration as detected in the laboratory was between 12% (lower value) and 15,.4% (upper value) Method and Equipment Used The measurement for a selected POHC during this test used US-EPA Method 30. This method could be used to describe the collection of volatile POHC from the stack flue gas of hazardous waste incineration through cement kiln. This method employs a 20-liter sample of flue gas containing selected volatile POHC in every run, which was withdrawn from a gaseous effluent source at a flow rate of 0.5 L/minute. It used a glass-lined probe and a volatile organic sampling train (VOST) known as slow (SLO) VOST conditions. Thus, a 40-minute sampling time was needed on each pair of absorbent cartridges or totally 120 minutes for three pairs of cartridges. Analysis of the traps was carried out by thermal desorption purge-and-trap through gas chromatography/mass spectrometry. These three traps were combined into one and analyzed to improve detection limit. PERC was chosen as a spike for this test. As the sampling test used a VOST train that operated at slow (SLO) VOST conditions (sampling rate of 0.5 liter per minute or LPM for 40 minutes or a 20 L sample volume per pair), only 3 (three) pairs of sorbent tubes per run were employed. EPA requires that triplicate VOST tests be conducted for each type of waste and/ or each type of operating condition (e.g. various waste firing rates). It required 3 (three) pairs of VOST tube samples of 40-minute sampling duration make a single test. A single VOST test took about 3 to 4 hours including time for changeovers. VOST used was the Graseby Nutech Model 200 Universal Sampler Control Console (see Figure 1). The VOST was employed for determination of POHCs emissions, such as PERC. The VOST utilized glass sorbent cartridges filled with Tenax TM resin to remove volatile compounds from the effluent gas as it was drawn through the sampling train. Distilled, deionized water was used as the rinse and recovery reagent. The VOST consisted of a stainless steel electrically heated probe with a borosilicate glass liner, a glass and Teflon TM valve, a glass coil tube water cooled condenser, a Tenax TM sorbent Measurement Of Selected.J. Tek. Ling. PTL-BPPT. Edisi Khusus:

5 cartridge, a moisture trap, a second glass straight tube water cooled condenser, a second sorbent cartridge of Tenax TM,charcoal, an umbilical, and the control console Sampling Procedure The procedure of sampling was as follows: Stack gas entered a heated probe to 130 o C to prevent moisture and volatile pollutants from condensing out of the gas stream and was collected in the probe. The gas then flowed through the valve and into the first condenser where the moisture and volatile compounds condensed out of the gas stream and were carried into the sorbent cartridge. The cooled gas and condensed volatile compounds were allowed to flow through the sorbent cartridge allowing complete adsorption of the volatile compounds. Excess moisture and water soluble volatile compounds were trapped in the moisture trap. The cooled filtered and partially dried gas sample then flowed into the second condenser, and down into the second sorbent cartridge containing charcoal to completely remove all volatile compounds from the gas stream before it reached the control console. All remaining moisture in the gas sample was condensed out by the second condenser and collected in the second condensate trap. The gas stream was further dried by passing through a desiccant trap (Silica Gel) prior to entering the umbilical cable and being carried to the control console Quality Assurance/ Quality Control All sampling and laboratory analysis procedures included a quality assurance/ quality control (QA/QC) program as an integral part of the overall technical effort. The objectives of the QA/QC program in this test were two fold. First, it provided the mechanism for controlling data quality. Second, it formed the basis for estimates of uncertainty associated with measurement data proviiding information for estimate error limits. The control function of the QC effort is based primarily on specific QC checks that are an integral part of the specified sampling and analysis procedures. Provisions for data quality assessment were also built into the test design. The following are some of the QA/QC checks conducted during performance of the test: Pretest leak checks across the entire train to ensure no leakage or at allowable leakage. Precleaning and proofing of glassware including achieving samples of rinse. Sample filters proofed (solvent washed) and one analyzed. Flowmeter tested against a calibrated flow meter. 3. RESULTS AND DISCUSSION For destruction determination, the concentration of PERC in the synthetic fuel (SF) delivered to kiln was measured. PERC feed rates were between 4x10 9 and 5.06x10 9 µg/min, as summarized in Table 1. The PERC emission test was carried out at low (slow-vost) flow rate sampling (i.e. approximately 0.5 L per minute in 40 minute sampling time per trap pair). Results of PERC emission rates from kiln # 2 are summarized in Table 2. Laboratory detection limit for PERC analysis was 2 ng. here were 3 (three) runs for POHC (PERC) measurements and all used a fuel 48

6 of PERC spiking HWF and coal mixture. Each run took about 120 minutes of sampling time and employed 3 (three) pairs of adsorbents. All three pairs of adsorbents were compositely extracted for the PERC content detection. Concentration of PERC in all 3 (three) tests were found to be above detection limit of 2 ng. The laboratory, trip and field blanks were all below analytical detection limit. Table 1. PERC feed rates to kiln # 2, PT.Semen Cibinong. Parameter Synthetic Fuel rate, t/h PERC conc. In synthetic fuel, % PERC feed rate, µg/min Test No. Lower Value x10 9 Sample Period (min) Upper Value x10 9 Table 2. PERC measurement at kiln # 2. Sample Volume (L) Using the formula given in equation (1) and test data given ini Table 1 and Table 2, the destruction removal efficiency (DRE) values were determined as summarized in Table 3. Because achievement of % destruction resulted in stack concentrations that were at or below ambient or laboratory levels for POHCs, contamination of samples could be a significant problem. The purpose of blank correction procedures is to account for any portion of the sample results that represent contamination, or something other than the value intended to be measured. The blank values are random samples that vary because of preparation, handling, and analysis activities. Under this assumption, blank values can be treated statistically. The best estimate for the blank for any particular sample is the mean of the available blanks. PERC Collected (µg) PERC Conc. (µg/nm 3 ) Stack Gas Flowrate (Nm 3 /min) [1] [2] [3] [4] [5] [6] Note: [2]: sampling data [3]: sampling data [4]lab. analysis of collected sample [5]: {[4]/[3]} [6]: sampling data There is a procedure available to determine whether a sample is different from the blank or not. A sample is different from the blank when: [Measured sample value] [Mean blank value] > [3 x blank standard deviation] Table 3. Summarized DRE values or Kiln # 2. Test DRE Lower Range, % [1] [2] [3] DRE Higher Range, % If the sample is not significantly different from the blank value, a sample cannot be blank-corrected. Since all the blank values in the tests performed were below the detection limit, a blank correction to the sample analysis was not Measurement Of Selected.J. Tek. Ling. PTL-BPPT. Edisi Khusus:

7 done. Therefore, the reported values of the samples in this paper are as measured values. 4. CONCLUSION The emission concentrations of POHC (PERC) from these tests were ranging from to µg /STD m 3. Since all blank values were all below detection limit of analytical employed, there were no correction to be made for the samples values. Therefore, the values of the samples were as measured ones. From calculations, the values of destruction for all three series of tests were above %. The three destruction tests all meet with the Indonesian regulation of % destruction for incineration of POHC or PCBs, as stipulated in the Decree of the Head of BAPEDAL, Kep- 03/BAPEDAL/09/1995. REFERENECES 1. American Lung Association, Recycling of Hazardous Waste Combustion in Cement Kilns, ml, February 26, Decree of State Minister of Environment No. Kep.- 13/MENLH/3/1995, regarding emission standard from stationary sources. 3. Decree of the Head of Environmental Impact Management agency No. Kep-03/BAPEDAL/09/1995, regarding Technical Requirement of Hazardous and Toxic Waste Treatment. 4. Decree of the Head of Environmental Impact Management Agency No: Kep-205/BAPEDAL/07/1966, concerning Technical Guidelines on Management of Emission Standard for Stationary Sources, Appendix II, BAPEDAL, Johnson, L.D Research and Evaluation of Organic Hazardous Air Pollutant Source Emission Test Methods. Journal of the Air Waste Management Association, Vol.: 46, December Liem,A.J.and Wilson M. A., A Quantitative Method for Evaluating Incinerator Test Burn Results, Air and Waste Management Association (AWMA), Vol.: 41, No: US Army Corps of Engineers, Fuel Blending and Cement Kilns HTRW Center of Expertise Information- TDSF, US-EPA Introduction to Boilers and Industrial Furnaces, 40 CFR Part 266, Subpart H, Updated October US-EPA Handbook Quality Assurance/ Quality Control (QA/QC) Procedures for Hazardous Waste Incineration, January US-EPA 40 CFR Part 60, et al. Revised Technical Standards for Hazardous Waste Combustion Facilities Proposed Rule, May 2, US-EPA Method 30 Volatile Organic sampling Train (VOST) Determination of Principal Organic Hazardous Constituents (POHCs). 11. US-EPA Guidance on Collection of Emission Data to Support Site- Specific Risk Assessment at Hazardous Waste Combustion Facilities, August 1988 Peer Review Draft 50