The Graham Technical Library contains articles developed by Graham Corporation for publication in various magazines and technical seminar presentations. The articles are organized in three categories; heat transfer, vacuum equipment, and steam surface condensers.
Cost savings by considering the use of a variable frequency drive for a liquid ring pump system.
Ejector systems are intended to support a refinery’s vacuum distillation process over several decades. But ensuring long-term performance reliability of these systems entails sustained investment in rigorous routine maintenance, repair , and operations (MRO) programs.
A complete understanding of ejector system performance characteristics can reduce the time and expense associated with troubleshooting poor crude vacuum distillation unit (CVDU) performance. Variables that may negatively impact the ejector-system performance of vacuum-crude distillation units include utilities supply, corrosion and erosion, fouling, and process conditions.
How ejectors work and properly operating ejectors and condensers is important in maximizing vacuum tower gas-oil yield
A system of compressors powered by surface condensing steam turbines is inherent in the operation of a typical ethane cracker unit. These turbines run by extracting work from high-pressure steam, while a surface condenser condenses the turbine’s exhaust to both maximize compressor horsepower and recover valuable condensate.
For decades there has been a marked uncertainty regarding the operation of steam jet ejectors in downstream facilities. This article reviews the functionality, performance and considerations of this important technology.
Sizing of steam surface condensers based on turbine steam flow which includes steam inlet velocity, cooling water flow and pressure drop, air leakage for design, fouling factors to use, ASME, HEI, and TEMA design codes, gas removal system design and space limitations for the condenser size.
Great strides have been made in improving plant efficiency and productivity by implementing online, interactive computer controls. But has this improved profitability or cash flow? How can the first-line management level know that its cash flow or ROI has been improved?
How to determine pressure drop, condensate leg height and other piping considerations for proper vacuum system design and operation
How to optimize and select the most economical steam ejector, process condenser, liquid ring pump system for capital cost and utility cost.
Best practices and opportunities to deliver reliable ejector systems performance and reduce performance risk.
A decades-old, yet less well-known type of heat exchanger offers advantages for new and emerging applications.
A seal cooler directly affects performance of a mechanical seal and extends its mean time between failures (MTBF). The heat removal and thermosiphoning capabilities of the cooler, its hydraulic characteristicstics, as well as its ability to remove trapped air (ventability) influence mechanical seal performance. API Standard 682, Shaft Sealing Systems for Centrifugal and Rotary Pumps.
Hydrocarbon Processing – Maintain Ejector Vacuum System
Steam ejector vacuum systems are reliable and require little maintenance. However, when preventive or corrective maintenance is required, ensuring it is done correctly is imperative.
Real world ejector system performance limitations uncovered during routine performance surveys. Corrective action undertaken to improve performance is documented and discussed in detail. Principles from the initial article are used as the tools to define the cause of a particular limitation and the eventual solution.
Crude oil refining and petrochemical industries make extensive use of condensers that operate under vacuum. Distillation is the most common process using these condensers, either as a process precondenser ahead of an ejector system, or as an intercondenser within an ejector system.
How to properly install a liquid ring vacuum pump, determine what accessories and controls are necessary and troubleshooting tips.
How liquid ring vacuum pumps work and the factors to consider when sizing a liquid ring vacuum pump for the application.
Environmental stewardship is becoming a priority for chemical plants as investors, corporate boards, government agencies and the public are demanding more accountability. For chemical processing plants, the release of volatile organic compounds (VOCs) from storage tanks is an area that often gets overlooked but is equally important to other sustainability targets, such as production processes, when it comes to meeting environmental, social and governance goals.
Ejector systems are widely used throughout the fats & oils processing industry for important processes, such as, solvent extraction, degumming, bleaching, deodorization, renewable diesel pretreatment or hydro-processing – wiped film evaporator and glycerin still are most common. Ejector systems provide reliable operation and pressure level for these critical fats & oil processing operations; however, there are instances where performance shortcomings arise. The root cause may not always be straightforward to troubleshoot. This article describes four case studies in performance problem solving taken from a variety of documents produced by ejector system experts.
How liquid ring pumps work and what devices are used to control the operation of a liquid ring pump system for proper operation.
Design Factors Operating Heat Exchangers at Ultra Low Temps
Ultra low, cryogenic, temperature applications for heat exchanger design for use in pharmaceutical and specialty chemical applications.
Plate heat exchangers may be selected for their high thermal efficiency and minimum capital investment. Spiral heat exchangers, on the other hand, are turned to for their ability to effectively handle fluids containing solids and fibers, similar to those encountered in wastewater treatment plants.
Variables Affect Cost, Performance and Reliability – Steam Surface Condensers
Steam Surface Condensers are critical equipment in a fertilizer plant, and can directly impact plant throughput and product quality. This article reviews key design decisions that affect capital cost and outlines operating variables that can negatively impact performance reliability.
Ejector system fouling can cost refiners millions of dollars annually. It leads to lost yield or lower throughput, either of which affects a refiner’s bottom line.
Turbine Operating Costs Depend on Condenser Performance
Saving energy and reducing a plant’s carbon footprint is vitally important in today’s world. One of a plant’s greatest energy users can be its steam-driven turbines. Steam turbines have excellent reliability and durability and are used to drive pumps, compressors, generators, and other rotating mechanical equipment throughout the refining, chemical, and petrochemical industries for processes that produce petroleum products, chemicals, fertilizers, electric power, and other products that are used every day by people around the world.
Essential processes in the production of natural fats and oils and derivative oleochemicals are performed under vacuum, i.e., at a pressure below atmospheric. Such processes, including solvent extraction, degumming, bleaching, interesterification, fractionation, winterization and deodorization, are supported by ejector systems.
How steam ejectors work and an analysis of ejector systems and troubleshooting tips with reference to case studies.
Detail design considerations involved in selecting steam ejector/liquid ring pump vacuum system for crude tower service. Materials of construction, energy utilization, packaging, system performance and flexibility will be addressed.
The Importance of Ejector Systems in Urea Plants
Ejector systems are critical to the final concentration of a urea solution.
Graham Manufacturing makes coiled-tube heat transfer equipment (Heliflow heat exchangers) which is frequently utilized as cryogenic vaporizers, with 80% of this service dedicated to liquid nitrogen. As a result of this testing, an analytical formulation for predicting boiling heat transfer rates in coiled-tube heat exchangers has been developed.
Alicia Johnson, Graham Corporation, highlights the strengths and weaknesses of traditional straight tube designs vs coiled tube designs in both condensers and heat exchangers.
Clean Air Act Amendments of 1990, which state acceptable rates for VOC emissions. Condensation technology allows reclamation of VOCs, providing an economic incentive when costly product is reclaimed as a condensate.
Fertilizer plants commonly use steam turbines to drive process air compressors, synthesis gas compressors, refrigerant compressors, electric generators and other mechanical devices. The cost of producing steam to operate the plant’s turbines is significant. Any adjustments in operation that can improve turbine performance will lead to reduced energy consumption and cost. Unfortunately, the equipment that is used to support the turbine is often overlooked. This article will explore the important relationship between operation of the steam surface condenser and its venting ejectors, and how their performance directly affects the fuel costs associated with operating a steam turbine.
Different types of vacuum pumps, piston, vane, dry, lobe, liquid ring, ejector, condenser, are discussed and the advantages and disadvantages of each type is provided.
Jim Lines, Graham Corp., USA, outlines how a solid understanding of best practices for specifying, procuring, and operating steam surface condensers, as well as good maintenance and performance evaluation practices, can help fertilizer plants to achieve their operating objectives.
Refiners can benefit from improved yield and lower vacuum residuum, thus improving refinery economics with minor modifications to the ejector system. Refiners continually optimise their crude slate, push the vacuum column for greater throughput and, for a variety of other reasons, operate the vacuum distillation unit under conditions different from the design basis. This can lead to dramatic increases in vacuum column pressure, especially during summer months when cooling water is warmest.