Site Visit Report

Union Carbide

— St. Charles Operations (SCO) 355 State Highway

3142 Hahnville, LA 70057 January 13, 2010 1.0 Background and Objectives The Environmental Protection Agency (EPA) is in the process of developing 316(b) cooling water intake structure requirements that reflect the best technology available (BTA) for minimizing adverse environmental impact for all existing power plants and manu facturing facilities. As part of this process, EPA staff is visiting electric generators and manufacturers to better understand the cooling water intake structure (CWI S) technologies in use at facilities, including the site

specific characteristics of each facility and how these affect the selection and performance of CWI S technologies. EPA is also visiting facilities to better understand cooling water use and specific issues or technologies that can affect 316(b) compliance. Dow ’s St. Charles Operations (SCO) facility was selected for a site visit because it utilizes cooling water in manufacturing a wide variety of basic and specialty

chemical products. 2 .0 Facility Description SCO is located on a 20 00 acre site on the shore of the Mississippi River near Hahnville , LA

. 1 The facility began operations in 19 66 2 and employ s approximately 1 1 00 personnel , plus as many as 1000 contractors . The facility ’s NPDES permit (NPDES permit number LA0000191 ) expired June 30, 2009 and has been administrativel y continued as the facility submitted its permit application and is awaiting a renewed permit

. 3 .0 Manufacturing Information Dow SCO is an integrated petrochemical plant 3 with 2 3 operating units that produce primarily

interm ediate chemical products. These products end up in a variet y of consumer goods such as plastics, insecticides, films and fabrics, antifreeze and brake fluid, paints and adhesives, pharmaceuticals, personal care products , and cleaning agents. According t o the company ’s website, the facility is capable of producing over 1 0 billion pounds of chemical product per ye ar.

1 At approximately river mile 128. A second, related facility (referred to as Eastbank) is located on a 40 acre parcel across the river in Norco. 2 The facility was originally owned and operated by Union Carbide, w hich was acquired as a who lly

- owned subsidiary of TDCC in 2001. 3 The term “integrated” refers to the interdependence of the operating units; raw products are brought onsite and then developed into intermediate and products in subsequent process units. In addition, the facility pr oduces its own water and power.The site is arranged in a series of complexes (e.g., hydrocarbons complex, oxide complex) that may

contain multiple plants. This site is al so home to four other companies: Air Liquide, Air Products, Praxxair, and Western

. 4 4 .0 Cooling Water System and Intake Structure SCO’s CWI S is located along the shoreline of the Mississippi River 5 near a receiving pier. Seven inlet pipes 6 each lead to an inlet bay (each with one single speed intake pump) , where a coarse mesh (3/8” mesh , ~48% porosit y) traveling screen removes debris and aquatic organisms

. Each screen bank is 10 ft wide and 36 feet in height. Screens are t ypicall y rotated twice per day by a high pressure wash and discharge to a common trough, which empties into a pit that drains back into the river. Facility

representatives stated that the screens are refurbished approximately

every 5 y ears. The through

- screen intake velo cit y is 2 feet per second (fps) at average water level of 20.5 ft and 4.6 fps at low water level of around 9 ft. The design intake flow (DIF) of the CWI S is 907 million gallons per day (mgd). T he average intake flow (AIF) is 773 mgd, which has remained r elativel y constant for the previous 4

- 5 ye ars. 7 The CWI S provides cooling and process water to a sy stem of internal canals that transport water throughout the facility . As many as twenty plants withdraw from the canal, use the water (or distribute it to other process units), and discharge to a similar series of return canals that connect to a discharge pumping station. This station is the primary

outfall for the facility

and pumps effluent back to the Mississippi River. The facility ’s fire suppression s ys tem withdraws from the cooling water canals. Facilit y representatives stated that sedimentation is not a significant problem at this site. Occasionally, dredging is required at the discharge point, but operators adjusted the discharge velocity to corre ct the settling problem. The facility

uses quaternary

amine as a biofouling agent to treat for clams. The CWI S also provides cooling water for Air Liquide and Praxair facilities.

4 Air Liquide and Praxair were previously part of the Union Carbide facility, but were sold off. 5 The mean annual flow of the Mississippi River at the site (river mile 128) is approximately 465,000 cfs (300,000 mgd) with an average width of approximately 3,000 feet and with a navigable channel of at least 45 feet depth. 6 The intake pipes project approximately 200 feet offshore to bring in cooler w ater and less debris beneath the water’s surface and withdraw from a depth of approximately 20 feet. The pipes have bar racks to prevent large debris from entering. A bulkhead on the upstream side (comprised of pilings and barges) protects the intake from large debris. 7 When the river’s water level is elevated, the facility can operate the intakes without turning on the pumps; the water flows into the CWIS and intake canal via gravity.5 .0 Flow Diagram A general flow diagram is provided in Attachment C. Facility representatives stated that 9 8.9 % of the water withdrawn is for once

- through cooling. The remaining water is clarified and then used for cooling tower makeup ( 0.4 % , ~3 mgd ) and other process uses ( 0.7 % , ~5 mgd ). There are five pump stations thro ughout the plant that feed 20 of the plant units. Canal water is returned via 8 pumps at a rate of 720,000 gpm. 6 .0 Electricity Generation and Transmission SCO operates two cogeneration power plants (i.e., produces both power and steam). Both were built in 1995, use once

- through cooling, and use natural gas and plant

- produced fuel gas (a b y - product of production). The electric generating capacity is a total of 240 MW and the steam generating capacity is a total of 80 MW
. Facilit y representatives also noted that SCO’s steam generation is heavil y integrated into the facility , as any change in steam production ripples through and affects production at multiple process units. Integrated chemical facilities (especially

those with basic process units) are often good candidates for cogeneration power plants. In fact, Dow has previously built “package” plants with a chlorine unit, a caustic unit, and a power plant

. Facilit y representatives stated that the power plants are not operated for profit, but for facility

reliability . SCO can produce its own electricit y cheaper than it can purchase it from the grid and also has a constant need f or both steam and electrici ty
. 7 .0 Impingement and Entrainment Information Dow has not conducted any biological studies at the site. 8 .0 Cooling Tower Feasibility SCO utilizes closed

- cy cle cooling (with mechanical draft cooling towers) at three plants , with helper cooling towers (i.e., supplemental cooling along with once through cooling) at two other plants

. When the facility was originall y designed, all of the cooling water needs were met with once

- through cooling water from the canal s ys tem. Howev er, as the plant expanded, water needs exceeded the capacit y of the canal sy stem and newer process units were built with closed

- cy cle cooling. As a result, process units built since the late 1990s (ty pically in locations further from the river) tend to us e cooling towers ; therefore the DIF has not changed because of the additional units . Facility representatives stated that 4% of thefacility ’s heat load is processed through cooling towers; without the cooling towers, the facility ’s intake flows would be slightly higher. Facilit y representatives noted that retrofitting remaining process units to closed

cy cle cooling would present a number of challenges. First, much of the piping used throughout the plant is operating at the upper end of the range for its design pressure . 8 A dding cooling towers would require additional pumps and likely require widespread replacement of piping throughout the facility

. Second , product reactivity

of water in certain process units could make both quality and safet y would be an issue : the increase in pressure could adversely affect some process lines that operate at lower pressures, leading to either a lower quality product, or in some cases, potentially dangerous chemical reactions. 9 Third, the difference in the cooling water temperature itself could have a negative effect on process and product capacity . An yt ime the process is condensing water, the cooler the better

. For the two cogeneration gas turbines, facility representatives indicated the pump station and distribution header would need to be re

- engineered. The facility also indicated that shell pressure issues may require retrofit of the heat exchangers. Facilit y representatives also discussed the role of cost in selecting the design of a cooling s ys tem: at a recently constructed facility

in Saudi Arabia, the cost of the cooling s ys tem (approximately $2 billion) was higher than the costs for all other environmental infrastructure combined. As such, they noted that cooling system retrofits would not simply be an issue of cost and affordability , but could even be a barrier to being competitive. Facilit y representatives stated that while individual process lines are periodically taken offline for maintenance, the entire facility rarely shuts down. In general, there is sufficient redundancy within the facility

to prevent widespread downtime; for example, boilers can be rotated to continue to provide steam. Each cogeneration unit is taken offline once per ye ar and other process units go offline as o ften as twice per ye ar or as infrequently as every 2

- 3 y ears. 9 .0 Future Activities SCO representatives were not aware of an y plans for significant changes or increases in operations.

8 Much of the piping is Gifford Hill piping, a reinforced concrete. 9 Changing to cooling towers can cause an increase in the cooling water system pressure which could adversely affect some process units.10 .0 Cooling Ponds There are no cooling ponds onsite. 1 1 .0 316(a) The facility

has no permit limitations for temperature or 316(a) permit conditions. 1 2 .0 Ash Handling There are no coal ash wastes generated onsite. 1 3 .0 Air Emissions Controls EPA did not review air emissions controls. 1 4 .0 Issues with Debris No significant problems with debris were noted. 15.0 Additional Information Facilit y representatives believe that 316(b) should be impl eme nted on a case by case basis as compliance should be customized to the site specific situation. Facilit y representati ves stated that, if forced to meet impingement requirements through use of a technology , they would consider evaluating installing cylindrical wedgewire screens, as these have been successfully implemented at Dow sites in West Virginia. They

added that there are not many other technologies that would be viable candidates at this site other than Ristroph screens

. If a cost benefit alternative is available for IM requirements, the facility stated they

would use this alternative. The facility

has not ev aluated entrainment reduction at this facility because it believes the costs of such controls would considerably outweigh any

benefits. However, they

noted that they

were not aware of any

available technologies to reduce entrainment at this site. The facility

also discussed way s in which waste heat recovery could be used to give cooling water credits. The difference in waste heat from the base case as compared to the heat rejected and recovered could be 10 to 20%. For example, if the BTU could be quantified, and the source cooling is known, then the BTU could be converted to a quantity of cooling water that would have been needed. As a general comment, s tand alone plants may have less dependence on fully integrated site power as opposed to larger i ntegrated manufacturers and utilities that generate power for sale.Attachments

Attachment A List of Attendees Attachment B Aerial Photos Attachment C PowerPoint Presentation (January 1 3 , 2010)Attachment A -- List of Attendees

Paul Shriner, EPA Jan Matuszko, EPA Kelly Meadows, Tetra Tech Christine Baldridge, Dow John Hill, Dow Tim Finley , Dow Ed Keough, Dow Qingzhong Wu, Dow Sarah Thigpen , Dow Bryc e Chord, Dow Maria Valdez, Dow (via telephone) Jim

- Bob Williams (via telephone)Attachment B -- A erial Photo

Please see DCN 10

- 6556A accompanying this document. Attachment C -- PowerPoint Presentation (January 12, 2010) Please see DCN 10

- 6556B accompanying this document.