CONSIDERATIONS REGARDING INCINERATION OF INDUSTRIAL PLASTIC AND HAZARDOUS WASTE: A CASE STUDY JAMES J. BINDER CSI Resource Systems, Inc. Boston, Massachusetts ABSTRACT The disposal of industrial wastes is becoming increas- ingly more difficult, costly and uncertain. Industry faces these problems for hazardous waste and "special" waste, such as highly chlorinated plastics, and sometimes for conventional wood, cardboard, and paper wastes as well. The future of hazardous waste landfills is unknown, pend- ing state legislation and the outcome of the debate to re- authorize the Resource Conservation and Recovery Act of 1976 (RCRA), which could further restrict future landfill- ing of hazardous waste. On the other hand, liability on the part of the waste generator is certain for those industries who continue to landflll hazardous waste. In addition, conventional sanitary landfls for disposal of wood and paper wastes are reaching capacity, and new landfll is are difficult to site. As an alternative to landfllling, on-site incineration of industrial waste with heat recovery offers potential bene- fits in terms of both disposal and energy cost savings. However, a decision to implement on-site incineration re- quires careful consideration because capital and operating costs can be significant, environmental requirements are stringent, and the technology has limited commercial operating experience with plastics and hazardous waste. This paper will review, by way of a case study of a manufacturing facility in the Northeast, technical, en- vironmental, business, and economic considerations when making a decision to install and operate an on-site in- dustrial waste incineration/heat recovery system. The case study focuses on incineration of hazardous wastes and highly chlorinated plastics. The case study example also addresses available incineration technologies that have been demonstrated for hazardous and "special" indus- trial solid waste. 458 INTRODUCTION Industry is increasingly facing a more difficult, costly, and insecure waste disposal future not only for hazardous wastes, but also for "special" wastes, such as plastic wastes high in chlorine content. The Resource Conservation and Recovery Act of 1976 (RCRA) is currently being reviewed by Congress, and recommended revisions to RCRA are likely to further re- strict the future landfling of hazardous waste. Further- more, several states - notably California - are initiating their own efforts to prohibit the landfllling of hazardous waste. A trend is thus developing, on both the state and federal level, which increases uncertainties surrounding the continued landfllUng of hazardous waste. In addition, across the country, conventional sanitary landfllis are reaching capacity; in many cases, it is becoming increas- ingly difficult to obtain permits to expand existing or to site new sanitary landfllis. As a long-term disposal option, land filling of both hazardous and nonhazardous wastes is, therefore, questionable in terms of availability and/or cost. In addition, under both RCRA and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (Superfund), the waste generator is liable for any hazardous waste if disposes of, even after such waste has been landfllied. Consequently, should a prob- lem arise in the future with a landflll in which hazardous waste has been deposited, the generator can be assessed a portion of the cleanup fee for that landftll. In light of these considerations, on-site incineration of waste with heat recovery offers many potential benefits, including: • The development of a long-term, controlled, and re- liable means of meeting waste disposal needs.
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Considerations Regarding Incineration of Industrial Plastic
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CONSIDERATIONS REGARDING INCINERATION OF
INDUSTRIAL PLASTIC AND HAZARDOUS WASTE: A CASE STUDY
JAMES J. BINDER CSI Resource Systems, Inc.
Boston, Massachusetts
ABSTRACT
The disposal of industrial wastes is becoming increasingly more difficult, costly and uncertain. Industry faces these problems for hazardous waste and "special" waste, such as highly chlorinated plastics, and sometimes for conventional wood, cardboard, and paper wastes as well. The future of hazardous waste landfills is unknown, pending state legislation and the outcome of the debate to reauthorize the Resource Conservation and Recovery Act of 1976 (RCRA), which could further restrict future landfilling of hazardous waste. On the other hand, liability on the part of the waste generator is certain for those industries who continue to landflll hazardous waste. In addition, conventional sanitary landfills for disposal of wood and paper wastes are reaching capacity, and new landfllis are difficult to site.
As an alternative to landfllling, on-site incineration of industrial waste with heat recovery offers potential benefits in terms of both disposal and energy cost savings. However, a decision to implement on-site incineration requires careful consideration because capital and operating costs can be significant, environmental requirements are stringent, and the technology has limited commercial operating experience with plastics and hazardous waste.
This paper will review, by way of a case study of a manufacturing facility in the Northeast, technical, environmental, business, and economic considerations when making a decision to install and operate an on-site industrial waste incineration/heat recovery system. The case study focuses on incineration of hazardous wastes and highly chlorinated plastics. The case study example also addresses available incineration technologies that have been demonstrated for hazardous and "special" industrial solid waste.
458
INTRODUCTION
Industry is increasingly facing a more difficult, costly, and insecure waste disposal future not only for hazardous wastes, but also for "special" wastes, such as plastic wastes high in chlorine content.
The Resource Conservation and Recovery Act of 1976 (RCRA) is currently being reviewed by Congress, and recommended revisions to RCRA are likely to further restrict the future landfilling of hazardous waste. Furthermore, several states - notably California - are initiating their own efforts to prohibit the landfllling of hazardous waste. A trend is thus developing, on both the state and federal level, which increases uncertainties surrounding the continued landfllUng of hazardous waste. In addition, across the country, conventional sanitary landfllis are reaching capacity; in many cases, it is becoming increasingly difficult to obtain permits to expand existing or to site new sanitary landfllis. As a long-term disposal option, land filling of both hazardous and nonhazardous wastes is, therefore, questionable in terms of availability and/or cost.
In addition, under both RCRA and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (Superfund), the waste generator is liable for any hazardous waste if disposes of, even after such waste has been landfllied. Consequently, should a problem arise in the future with a landflll in which hazardous waste has been deposited, the generator can be assessed a portion of the cleanup fee for that landftll.
In light of these considerations, on-site incineration of waste with heat recovery offers many potential benefits, including:
• The development of a long-term, controlled, and reliable means of meeting waste disposal needs.
TABLE 1 CASE STUDY: COMPOSITION OF WASTE (AS-RECEIVED)
MATERIAL
PVC Materials
Urethane Foam
Polyurethane Plastics
Wood and Cardboard
Li qui d Waste
• A significant reduction in the volume of waste that has to be disposed of in a landfIll (the residue remaining after incineration), with an associated reduction in haul costs and disposal fees.
• The implementation of a waste disposal system that may reduce or eliminate waste generator liability for continued landfIlling of hazardous waste.
• An alternative energy source with an associated reduction in dependence on uncertain supplies of fossil fuels and price variability.
• Energy cost savings to the industry. In order to ensure that these benefits are achieved; the
decision to install and operate an on-site incineration/heat recovery system requires careful review. Capital and operating and maintenance (O&M) costs can be significant, particularly if the incinerator is classified as a hazardous waste incinerator; emission requirements are stringent, again, particularly for hazardous waste incinerators; and the technology and suppliers of the technology have limited commercial experience with hazardous and "special" wastes.
The remainder of this paper reviews, by way of a case study, technical, environmental, business, and economic issues when considering on-site incineration with heat recovery as a solution to industrial waste disposal problems. As part of the case study, a questionnaire was widely circulated and interviews and site visits were conducted to review currently available industrial waste incineration systems.
DEFINITION OF CASE STUDY
The case study presented is based on an operating manufacturing facility in the Northeast.
WEIGHT AS PERCENT OF TOTAL
61
11
8
15
5
100%
WASTE QUANTITY AND CHA RACTE RISTICS
The total quantity of waste produced by the plant is 25 tons per day (TPD) (22.7 t/day) on a 7 -day-per-week basis. Approximately 95% of the waste is solid material, and the remainder is liquid material (Table 1). The solid and liquid wastes are collected and stored separately.
The solid waste consists of PVC materials, urethane foam, polyurethane, wooden pallets, and cardboard wastes. As a result of process cleaning, a small fraction of the urethane foam waste is contaminated with methylene chloride, which is listed as a hazardous waste by the Environmental Protection Agency (EPA), and is segregated from the other solid waste. The solid waste is generated in various sizes. For example, a portion of the PVC waste is in the form of long strips several inches wide and up to several feet in length, and foam pieces may be as small as 1 in. (2.54 em) by 2 in. (5.08 em).
459
The liquid waste consists of variable quantities of xynol, acetone, methyl diisocyanate, toluene diisocyanate, methyl ethyl ketone (MEK), and toluene. MEK and toluene are listed by EPA as hazardous wastes. Xynol, acetone, and toluene diisocyanate are hazardous materials according to EPA ignitability criteria.
Table 2 presents the ultimate analysis of the waste (solids and liquids) on an as-received basis.
The waste presents several potential problems for incineration and heat recovery. First, if size reduction of the waste is required for feed to the incineration unit, it will increase the complexity and cost of the total incineration/ heat recovery system. Second, the presence of chlorine in the waste and the formation of hydrochloric acid (HCI) during incineration will result in material corrosion and require scrubbing HCI emissions to meet state environmental requirements. Moreover, burning the liquid waste
TABLE 2 CASE STUDY: ULTIMATE ANALYSIS OF WASTE (AS-RECEIVED)
HIGHER HEATING VALUE
MATERIAL
Carbon Hydrogen Nitrogen Sul fur Chlorine Oxygen Moisture Inerts*
12,000 Btu/lb (27,900 k-joules/kg)
WEIGHT AS PERCENT OF TOTAL
48.6 6.4 2.2 0.0
18.6 15.3
5.0 3.9
100.0%
* Inerts contain 0.3042-percent barium, 0.1432-percent cadmium, and 0.0644-percent zinc by weight of the total waste.
or the contaminated foam waste may result in the classification of the facility as a hazardous waste incinerator, which will require compliance with more stringent environmental requirements, including 99-percent HCl removal (or a reduction of HCl emissions to 4 lb/h) and a 99.99% destruction and removal efficiency for hazardous materials.
MANUFACTURING FACILITY ENERGY USE
The manufacturing facility currently uses three 10,000 lb/h (4,536 kg/h) oil-fired boilers to produce low-pressure steam for use in dryers and space heating. In addition, propane-fired heaters are used on several process lines. Electricity requirements are met by power purchased from the local utility.
Over the past several years, the manufacturing facility has experienced substantial increases in energy costs resulting from both oil price and electricity rate increases. Table 3 gives the manufacturing facility's energy usage and energy costs in 1980 and 1981.
SYSTEM CONCEPT DESIGN
The proposed concept deSign calls for the system to cogenerate electricity and steam, with steam as the primary energy market. The proposed system will:
• Consist of a minimum of one and a maximum of three incineration units with heat recovery and a 1 MW turbine-generator.
• Be capable of combusting all of the plant's solid and liquid wastes [equivalent to 25 TPD (22.7 tpd) on a 7 -day -per-week basis] .
• Be capable of operating 24 hours per day, 7 days per week with minimal supervision and attendance.
• Include air pollution control equipment to achieve the following in compliance with federal, state, and local environmental laws and regulations:
. - A particulate emission rate not to exceed 0.08 grains per dry standard fe at 7% O2,
- A minimum of 99% removal of HCI (or 4 lb/h of HCI emissions) in the stack gas, with a maximum HCl concentration of 136 ppm.
- A 99.99% destruction and removal efficiency for each principal organic hazardous constituent.
PREFERRED PROJECT STRUCTURE
• The manufacturing entity will: - Be the facility owner and operator. - Provide the financing for the inCineration/heat re-
460
covery system. - Provide the site for the incineration/heat recovery
system.
TABLE 3 CASE STUDY: E NE RGY USAGE AND COST
FISCAL YEAR
1980
1981
" Change from
PROPANE
100 cu ft
1,284,562 (3,635,300 cu meter)
1,416,811 (4,009,600 cu meter)
FY 80 +10"
April 1982
FISCAL YEAR *6 OIL
gals
tll00 cu ft
53t
60t
+13"
51t .
tlga1
1980 483,814 59t (1,831,236 1)
1981 429,885 77t (1,627,115 1)
S Change from FY 80 -la
April 1982
+3a
66t
461
Cost
$679,735
$846,284
+25"
Cost
$284,642
$332,724
+17"
" of Total Energy Costs
41"
39S
" of Total Energy Costs
17"
15"
•
FISCAL YEAR
1980
1981
'I. Change From FY 80
April 1982
ELECTRICITY
kVa
Max 2706 (Nov) Min 2451 (J!ln) Avg 2586
Max 2702 (Dec) Min 2438 (Feb) Avg 2529
Summary of Energy Costs
TABLE 3 (continued)
kWh t/kWh
14,847,000 4.57t
15,723,000 6.37t
+6'I. +39'I.
6.4U
Cost
$078,356
$1,001,541
+481.
'I. of Total Energy Costs
46'I.
FISCAL YEAR �C�OS�T ____________________________________________ __ ______ __
Propane
1980 $ 679,735
1981 $ 846,284
� Change From FY 80 +25'I.
#6 Oil
$ 284,642
$ 332,724
+17'I.
462
Electricity
$ 678,356
$1,001,541
+48'J.
Total
$1,642,733
$2,180,549
+33':.
Provide the necessary utilities at the site. Complete any necessary changes in its existing facility, including changes to existing steam lines and the electrical system, to accept the energy output of the incineration/heat recovery system. Supply facility waste, as well as any supplemental fuel that might be required, to operate the incineration/ heat recovery system.
• The selected vendor will: Design, construct, start up, and acceptance test the incinerator aI:1d provide training to the manufacturing facility's staff. Operate the incineration/heat recovery system for at least 1 year to ensure a smooth transition to the staff. Perform all site preparation work. Provide tie-ins to utilities and plant steam and electrical distribution systems. Provide system performance guarantees, including environmental compliance guarantees.
EVALUATION OF COMME RCIAll Y
AV AI lABlE SYSTEMS
Once having established a design concept and a preferred project structure, it was necessary to determine whether technology was available having commercial operating experience on the types of wastes produced by the manufacturing facility and, if so, whether the vendors of this technology would offer this technology in accordance with the preferred project structure. This process entailed issuing a questionnaire to vendors of potentially applicable technology, evaluating the vendor responses, and conducting vendor interviews and site visits.
In mid-1982, a detailed technical, environmental, and business questionnaire was sent to 15 prospective vendors to determine if commercially demonstrated technology was available for the incineration of the types of industrial waste under consideration. Detailed responses to the questionnaire were received from nine vendors representing controlled air hearth incinerators, rotary kiln incinerators, and a pyrolysis unit. These responses were evaluated on the basis of demonstrated experience with similar wastes, ability to comply with the preliminary system specifications, and willingness to provide turnkey services (Le., design/construction with short-term operations/training and performance guarantees). Table 4 provides a comparative analysis of the vendor responses received.
As a result of the initial evaluation, three vendors were found to have insufficient experience in incinerating waste similar to that of the manufacturing facility. The six remaining vendors were selected for detailed interviews. Table 5 summarizes, by technology, preliminary cost esti-
463
mates construction sched ule, and most relevant commer-, cial experience based on the information provided by these six vendors.
TECHN ICA l/ENVI RONMENT A l/BUSI NESS
CONSIDE RA TI ONS
The vendor evaluation indicated that: • Incinerators are available that can accommodate
highly chlorinated plastic and hazardous plant wastes, but they are limited in number. In addition, these systems have limited commercial operating experience (on the order of 1 to 3 years).
• Experience with heat recovery from incinerators burning highly chlorinated plastic waste is extremely limited, although vendors expressed confidence in the ability to do so, including the ability to produce turbinequality steam. [In all cases, it was recommended that maximum steam temperatures be limited to 600°F (315°C) to minimize corrosion.]
• The chlorine content in the waste should be limited to no more than 25% to 35% to protect the equipment, including the refractory, from excessive corrosion.
• EPA hazardous waste incinerator design criteria can be met for particulate control, HCI control, and destruction of prinCipal organic hazardous wastes. Vendor experience indicates that a venturi scrubber followed by a packed tower utilizing water or caustic as a reagent has been proven to be capable of achieving the particulate and HCI control criteria. The packed tower, however, will produce a sizable wastewater discharge in the form of either diluted HCI acid solution or salt water [20,000 to 50,000 gal/day (75,700 to 189,250 L/day)]. This discharge can present a difficult disposal problem, particularly if a sanitary sewer system is not accessible or a market does not exist for HCI acid. Vendors did not propose the use of dry scrubbers or coated baghouses because of lack of commercial operating experience for such units. Confidence was expressed in the ability to meet the 99.99% destruction criterion, as the incinerators operate at temperatures in excess of 2000°F (1093°C) with residence times of at least 2 sec.
• Vendors will provide turnkey services and a performance bond to guarantee the performance of their systems.
• Capital and O&M costs can be high.
RELATIVE ECONOMICS
Once. having established that commercially proven technologies were available under the terms of the preferred project structure, a preliminary economic analysis
TABLE 6 CASE STUDY: COMPARISON OF AVAILABLE COMMERCIALLY DE MONSTRATE D
INCINE RATION SYSTE MS
TYPE OF INCINERATOR
Horizontal Rotary Kiln
Controlled Air Hearth
PRELIMINARY COST ESTIMATES (1981 $)
Capitala
($ M)
2.2-14. d
2.Sd
O&Mb
($k/yr)
900e-1,400
3S0
CONSTRUCtION SCHEDULE (months)
12-24
10.S
Conventional Waterwall 2.4-3.1 1,200-1,300 18
Pyrolysis/Rotary Hearth 2.4-3.8 2S0-280e
MOST COMPARABLE TYPE OF WASTE INCINERATED
Liquid hazardous wastes, chemical wastes, paper, wood pallets
95% plastic wastes (PVC, polyethylene, nylon)
Plastic wastes, cardboard, paper, wood pall ets
Chemical wastes, paper, wood pallets
a. These capital cost estimates are for a complete installed system: front-eno processing (if necessary), waste feed system, combustion system, energy recovery system, and air pollution control train. Turbine-generator costs are not included, except where otherwise noted.
b. The preliminary O&M cost estimates include O&M staff salaries, supplementaO, fuel' costs (except where otherwise noted), maintenance, and repair parts. Residue (ash) disposal is not included.
c. System design and construction through acceptance.
d. The $14-mill i on estimate al so i ncl udes turbi ne-generator costs and necessary buildings and foundations. The $2.S-million estimate also includes necessary buildings land foundations.
e. Supplemental fuel and electricity not included.
f. Includes bench-scale and pilot-plant test.
468
TABLE 6 CASE STUDY: SAVINGS VS. COST (1982 $)
ITEM
Capital Cost
Operating Costs
Energy Savings:
---
Oil Propane Electricity
Oil-Fired Boiler Operating and Maintenance Savings
Solid Waste Disposal Savings
TOTAL OPERATING AND ENERGY SAVINGS
NET OPERATING SAVINGS
was conducted for the recommended system concept design to determine whether or not the incineration/heat recovery system appeared to provide an economically viable solution to the manufacturing facility's disposal problem. System costs and savings were estimated, and the internal rate of return and payback period were calculated as a measure of economic attractiveness. Operating savings versus costs are shown in Table 6.
The preliminary economic analysis was based ori the following:
• All of the manufacturing facility's waste is processed in the incineration/heat recovery system.
• 100% of the manufacturing facility's anticipated oil use and 50% of its anticipated propane use (125% of 1981 use) are offset by the steam output of the new system.
• 2,000,000 kWh/year of electricity are produced, thereby reducing the manufacturing facility's purchased electricity requirements.
The preliminary economic analysis used capital and O&M cost estimates from the low end of the range provided by the vendors, in order to first ascertain the economic attractiveness of the system under a "best-case"
COSTS/SAVINGS
$3,400,000
300,000
$ 414,000 509,000 127,000
90,000
201,000
$1,341,000
$1,041,000
scenario. The capital costs selected for the analysis were $3.4 million and the O&M costs were $300,000.
The results of the analysis are as follows: Internal rate of return on total system (after tax) 17.9% Payback period on total system (after tax) 3.4 years Internal rate of return on turbine (after tax) 23.7% Payback period on turbine (after tax) 2.8 years
CONCLUSIONS
It can be concluded that on-site incineration of industrial plant wastes, including highly chlorinated plastics and hazardous waste, is technically and environmentally viable. Commercial application of available technology on hazardous and "special" industrial waste is, however, limited. A system can be procured on a turnkey basis with the backing of a performance bond. While capital
469
and O&M costs can be high, the energy savings from inclusion of heat recovery can offset these costs. The deci-
sion that must be made is whether the cost is justified to limit waste disposal risks and uncertainties.
Key Words: Aluminum . Analysis. Composition. Com
posting. Construction • Control • Disposal Liability •
Economics • Decision Making • Fly Ash • Refractory