WASTE MINIMIZATION: THE CHEVRON EXPERIENCE

Transcription

1 h V WASTE MINIMIZATION: THE CHEVRON EXPERIENCE Dan Kauffman Environmental Specialist Chevron Corporation San Francisco, California Dan Kauffman is currently Chairman of the Alternative Technology Task Force in the American Petroleum Institute. The task force is currently preparing a study on a variety of waste minimizing technolodes to determine if thev meet EPA requirements for the Land Disposal Ban. He also chairs a task force in the Western Oil and Gas Association which is preparinp a primer on waste treatinp technologies applicable to the oil industry. It will discuss operating problems, utility requirements, permitting, costs and operating experiences. Mr. Kauffman is currently an Environmental Specialist in the field of waste management for Chevron. Previously he has been employed as a staff engineer and supervisor by Chevron. He received his Chemical Engineering degree from the University of Colorado in

2 Waste Minimization. WASTE MINIMIZATION: THE CHEVRON EXPERIENCE Dan Kauffman Environmental Specialist Chevron Corporation Chevron believes good hazardous waste management is good business. An important part of hazardous waste management is waste minimization which includes source control, recycling, and treatment for toxicity and volume reduction. Chevron committed in 1982 to expedite the use of on-site recovery and treatment and to reduce off-site disposal dependence. Following are several examples of how we are meeting that commitment, a summary of our short and long-term goals and some of the logistical problems we are encountering. INCENTIVES FOR WASTE MINIMIZATION Chevron reclaims as much material as possible from our wastes. On-site waste reduction, treatment, and recycling reduce the volumes transported offsite, thereby minimizing the possibility of transportation problems. These onsite techniques minimize the exposure of the public to hazardous wastes, and minimize the liability exposure to Chevron. They can also reduce costs for disposal, taxes and internal (sometimes hidden) handling charges such as storage. We evaluate iong term costs incliidiiig!iabi!ity asschated with landfilling to irn prove economics for capital expenditures. 152 GOVERNMENT INSTITUTES. INC

3 Waste Minimization HOW FAR CAN WASTE MINIMIZATION TAKE US? Before we discuss these waste minimizing techniques, it is important to note that except in a few cases, waste minimizing techniques typically do not eliminate entirely the need for landfill disposal. Most waste reducing techniques result in residues for landfill disposal, but in quantities which are smaller than the original hazardous wastes. Some waste reducing techniques reduce or eliminate the hazardous character of the waste. Other techniques contain the waste in a manner which prevents or minimizes human or environmental exposure. PROCESS MODIFICATION TO MINIMIZE WASTE A Chevron lube oil warehouse and packaging plant in Louisville, Kentucky, has an on-site, 55-gallon-drum cleaning and painting facility. Prior to the modifications of the drum reconditioning facility, drums were washed with a caustic liquid and rinsed with water. This resulted in the generation of 500 gallons per day of a caustic, oil, paint, and water mixture. The caustic rinsate mix did not meet the local sewer district's wastewater discharge limitations and had to be disposed of as a hazardous waste, costing the company $50,000 a year. Similarly, paper filters which collected the overspray from the solventbased paint spraybooth also posed a disposal problem. Furthermore, the filters did not provide adequate air emission controls, and additional measures to reduce solvent emissions from the paint spraybooths were required. Employee exposure to the noise, caustic vapors, and solvent-based paint were described in a company report as unacceptable. Over a 3-month period the company evaluated a variety of prospective solutions to alleviate these conditions, including upgrading the existing system, and subcontracting drum reconditioning to an outside vendor. Economic considerations, however, favored the installation of a state-ofthe-art drum washing, reconditioning, and painting system. The new system uses only high-pressure hot water to wash the drums. The oil is reclaimed and the water is reheated and reused. A small volume of wastewater is discharged to the local sewer district and is within the wastewater discharge limitations. The reclaimed oil is sold to a recycler, netting Chevron $12,000 per year. '4 substitution of water-based paint for the solvent-based paint and by using stateof-the-art overspray filtration equipment now conserves paint and eliminates the generation of hazardous waste paint residue. Efficiency has been greatly enhanced by the new system; down time has been virtually eliminated; plant capacity was increased by 700 drums per day; and, savings of $2j,OOO ppr year ifi persenfie! CQS~S, and ef cl Qnn nor yea: i: maintenance a nd other e qu i pm en t costs have be en re a1 iz*evd:y " "A;>; ti onall y, caustic and other chemical material costs have been reduced by $13,400 per year, with a similar savings of $5,000 in yearly paint costs. Total savings to Chevron from these modifications exceed $80,000 per year after the 3-year payback period. 153 GOVERNMEW INSTITUTES. INC

4 Waste Minimization RESOURCE RECOVERY AND IN-PLANT RECYCLING Resource recovery and in-plant recycling offer obvious benefits including savings in raw materials cost. Petroleum processes are designed to incorporate recycling techniques to utilize raw materials efficiently. Recently, Chevron has begun utilizing mechanical separation equipment to remove the last bit of oil from oily wastes. More on that later. HOW OIL IS RECYCLED An example of in-plant recycling in the petroleum industry is the practice of oil recovery in refineries. Modern refineries produce numerous products and include many process units. The units in refineries vary due to the nature of crude oil feedstocks or product lines. Furthermore, those units in operation at any given refinery will vary with the desired product mix, which is in turn affected by market forces and time of year. In spite of these differences, a general block diagram for a "typical" U.S. refinery is shown in Figure 1. This diagram is intended to represent only the basic units that are found in most refineries. It should be emphasized that no two refineries are identical, either in their operations or their facilities. The recycle of oil recovered from waste streams is indicated in Figure 1. Recovered oil is typically stored in a tank for gradual feed to refinery processes. The broken lines on Figure 1 indicate that recovered oil may be fed to the Crude Distillation Units, the Fluid Catalytic Cracker, or the Cokers. The different recycle points for recovered oil are included to show that refiners may follow different practices and that a single refiner may have more than one option available for recycle of recovered oils. Recycled oil comes from oil skimming from API separators. The primary purpose of the API Separator is to recover oil that has been in contact with utility, cooling and process waste waters. Recycled oil also comes from the treatment of slop oil emulsion solids (SOES). SOES contain oil, water and solids. SOES has been designated as RCRA hazardous due to the potential presence of lead and chromium. Another source of recycled oil is off-spec products. INCREASING OIL TO BE RECYCLED-DECREASING WASTE Chevron has improved oil recovery from wastes at several of its refineries by mechanically treating oily sludges to remove oil. Example oily sludges are API separator sludge (listed as RCRA hazardous due to metals), tanks bottoms from tank cleaning and DAF float (a wastewater treating waste listed as RCRA hazardous). Initial results indicate these waste sludges can be effectively minimized using this type of process. Figure 2 shows a diagram of a commercial belt filter press that can be used to treat refinery oily sludges. Sludges are pressed between rollers to remove oil and water from the solids which are present. Depending on the original solid 154 GOVERNMENT INSTITUTES. INC

5 L I Fuel Gas 4Fuel Gas - Crud l- Dis t i I lot Ion - Strtdight Run Gasoline LPG h - Naphtha Hydro. Treat in& Mi dldl e I_ Disl'i ila tes -1 Gas 011 Residue - ""I. ". Hydro- Plant Plant 1 I - I -3LPG -+Motor Gasofin --*Solvents -Aviation --+Diesels Fuel --@Heating Oils -Fua I.Oi Is --*Aspha1 t 1. c ' Coking i L I Coke i Unit I Recycle Ld Storage FIGURE I "TYPICAL" REFINERY FLOW DIAGRAM

6 FIGURE 2 CONCEPTUAL DIAGRAM COMMERCIAL BELT FILTER PRESS Sludge Feed / Discharge (Fan) 7 Gravity Section Wedge Section c Top Belt Belt Scrapers- Cake Discharge Bottom Belt Pressure Section

7 Waste Minimization contents, the treatment can reduce the weight to be disposed by 50% or more. Oil recovered from this process can be routed back to the refinery to make products. The water can be routed to the refinery's wastewater treatment system. Figure 3 shows another process that can treat refinery oily sludges with similar results to the belt filter press. Chevron is also investigating the use of solvent extraction processes to reduce oily waste volumes to be disposed. The use of a solvent can significantly reduce the oil remaining on the solids. If the solids residue is "clean" enough it is hoped that the residue can meet the strict new land disposal ban requirements currently being developed by the EPA. The solvent extraction processes are just beginning to be used commercially and must be further developed before they will have a significant impact on hazardous waste dis posal. SOURCE SEGREGATION OR SEPARATION Source segregation results in a smaller volume of concentrated hazardous waste. It prevents contamination of larger volumes of non-hazardous waste. Examples Chevron uses are: o o o isolation of hazardous materials from nonhazardous materials isolation of hazardous waste by contaminant isolation of liquid from solid waste BIOLOGICAL TREATMENT Biological treatment refers to a broad range of treatment options utilizing microorganisrns or "bugs", or enzymes derived from microorganisms to metabolize and break down organic wastes. Biological treatment is a widely used, well established method for treating industrial wastes containing organics. Typically the microorganisms used in a biological process are naturally occurring microorganisms which are already present in the environment. Under favorable process conditions such as temperature, contact time, and nutrient levels the microorganisms proliferate and metabolize the organic wastes at a relatively high rate. Chevron uses this biological process in several locations across the country to reduce organic waste volumes in what is known as landf arms. The main end products of the aerobic biological process are carbon dioxide and water. Also typically formed is a residue which consists of dead and living nro=m;rmc 3nrl nnn-hinannr3rlnhln "L gun,191 I ma, U I I" I IWI I - U I W U L ~ L UUUYIL innrn=nir cnl iac I, I", 6 - a.ab.a"& *".a. Cionifirsnt I l l A ~ U I c. rmrltirtinnc. \-YUb.I". waste volumes can be achieved by landfarms. If the incoming waste contains heavy metals, these may be concentrated by the microorganisms into the residue phase. Metals are practically immobilized in the aerobic soil environment of a landfarm. Landfarms are similar to incineration in that organics are reduced to carbon dioxide and water; and the heavy metals are concentrated in the residue phase.. I.. in 157 GOVERNMENT INSTITUTES. INC

8 FIGURE 3 CONCEPTUAL DIAGRAM DECANTER CENTRIFUGE Drum Scroll P) 0 a Centra te Drain Feed Cake Discharge

9 Waste Minimization 1 NCINE RATION Incineration is a thermal destruction process which oxidizes wastes, mainly organic wastes, by exposing them to high temperatures in the presence of oxygen. When incineratable hazardous wastes are exposed to incineration temperatures up to 30000F, they rapidly break down into simpler and less hazardous compounds. The main products from incineration include water vapor, carbon dioxide, and ash. Government performance standards require 99.99% destruction for hazardous waste incineration. Chevron recently contracted for an incinerator known as a circulating bed combuster from G. A. Technologies for the treatment of PCB contaminated soil near Swanson River in Alaska. The soil residue after combustion will contain essentially no PCB's and will be disposed in place. The alternative was to move the PCB contaminated soil to a permitted landfill in the lower-48 states.' Alaska has no permitted landfills. This option was rejected even though it was less costly in the short term because incinerating the waste will eliminate long term liability for Chevron. Incineration will be an increasingly important technology for certain hazardous wastes. California law requires certain hazardous waste that contain greater than 3000 Btu/lb heat content be incinerated after January I, Other approved treatment processes may be approved in the future by the California Department of Health Services. Federal law now requires treatment of solvent wastes before disposal. One EPA approved form of treatment for solvent wastes is incineration. FI X A T ION Chemical fixation/solidification processes reduce the mobility and leachability of wastes prior to landfill disposal. This process can be used to immobilize metals which occur in petroleum industry wastes. Techniques include : (I) Pozzolanic (fine-grained silica) materials such as fly ash may be mixed with lime and water to solidify hazardous wastes. This technique can be use on Fluid Catalytic Cracker catalyst fines which are a California Hazardous waste. (2) Surface encapsulation may be used to coat the waste with a layer of protective, im perm ea ble mate rial. This technd00" OJ may, i! fact, C2llSP SOmP additinna! vn!nme fnr!andfi!! disposal due to the inclusion of solidification material. Organic wastes tend to interfere with the setting and curing action of solidifying agents. 159 GOVERNMENT INSTITUTES. INC 0 I986

10 Waste Minimization Chevron in association with Ven Virotek in Ventura County, California has been chemically fixing non-hazardous drilling muds using pozzolanic mate rials. The purpose for fixing the mud is to solidify any liquids present. The resulting material looks much like soil and is being used as ground cover for a municipal landfill. SHORT TERM OBJECTIVES Chevron has had a long standing objective to minimize waste that must be disposed off-site. We have made good progress in this area and we are continuing to look for other opportunities. Chevron facilities, assisted by research and corporate staff, are actively pursuing additional waste minimizing alternatives that offer solutions to our wastes. Chevron is taking leadership role in studies of waste minimizing technologies being conducted by the American Petroleum Institute (API) and Western Oil and Gas Association (WOGA). The API study will determine if a variety of waste minimizing technologies meet EPA requirements for the Land Disposal Ban. The WOGA study will produce a primer on waste minimizing technologies applicable to the oil industry. It will discuss operating problems, utility requirements, permitting, costs and operating experiences. Chevron was also instrumental in the formation of a consortium of oil companies now called PERF, which among other things will research innovative ideas for waste treatment. LONG TERM OBJECTIVES The following are Chevron Long Term Objectives: (1) Maximize internalization of waste management (2) If a waste cannot be avoided altogether, render the waste nonhazardous before ultimate disposal (3) Lower permitting hurdles for waste minimizing technologies LOGISTICAL PROBLEMS Many types of waste minimization technologies require permitting from federal, state and local agencies including air pollution control districts. In some instances, such as incineration the permitting hurdles are so high that it is all but impossible to get permits to build a facility. Regulators must pursue ways to streamline permitting without jeopardizing public health. Treatment -+ ui *-*--*- wa3t.c,*-l* UIIUCI the Federa! Land Dispnsa! R-n requirernents involve waste minimization technologies. Because of permitting delays it may be impossible for companies to meet the deadlines imposed for installing such equipment in the coming four years. 160 GOVERNMENT INSTITUTES. INC

11 . Waste Minimization Quantifying benefits such as long term liability are also difficult. One study that was helpful was 'Comparison of the True Costs of Landfill Disposal and Incineration of DOD Hazardous Wastes", Draft Report, ICF Technologies, September It estimated disposal of wastes could have long term liabilities of varying amounts for a generator depending on the mobility of the waste constituents. It is crucial that a company have top management support for long term waste management goals to overcome the "softf1 economics of long term liability. Another logistical problem is that many waste minimizing technologies are just becorning commercial. Previously they have only been tested on the bench or pilot scale. Serious problems with operating a "new" technology frequently occur at the commercial scale that sometimes makes the technology cost prohibitive. One should be careful not to embrace a new technology before it is fully demonstrated at a commercial scale. Another problem stems from federal "mixture" and "derived from" rules. Water streams produced by some of these waste minimizing techniques have been in contact with hazardous waste. Chevron is working with the EPA to show that these water streams are clean enough not to be regulated as hazardous wastes, and are properly managed in waste water treating systems. 161 GOVERNMENT INSTITUTES. INC 0 19Bt

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