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Steam and Thermal Systems

Steam and Thermal Systems by Veerasamy Venkatesan, general manager, VGA Engineering Consultants, Inc.

Veerasamy Venkatesan is the general manager of VGA Engineering Consultants, Inc., Orlando, Fla. He is a Certified Energy Manager (CEM), and a U.S. Dept. of Energy approved specialist in assessing both steam and process-heating systems, qualifications possessed by only a few energy professionals in the U.S. He has more than 28 years of field experience related to plant operations and process engineering at chemical, petrochemical, refining and other facilities. He has successfully solved steam and thermal system problems at sites around the world.

Why are we getting wet steam from the electric steam generator?
We are facing a problem with an electric steam generator operating on a controller that limits the power allowed to be use by the generator. We get wet steam that causes us operating problems in a feed mill plant that requires only dry saturated steam.

We want to understand the process of steam generation on Mollier diagram and estimate the quantity of water that is carried with steam.

We also need to plan the revision of the steam network.

That boiler operates between 105 and 110 psig with a modulating feed valve on water. It is a 12-stage boiler of up to 984 kW.
Category: Steam and Thermal Systems

How do you recycle the blowdown steam?
How do you recycle the blowdown steam generated from a fire-tube boiler (15 tons capacity)? Is there any equipment to recycle it?
Category: Steam and Thermal Systems

What's involved in changing from an electric motor to a steam turbine?
We are considering changing the electric motor drive on our air compressor to a steam turbine to reduce available steam letdowns. We do not have any steam turbines and so do not know much about them.

Would the air compressor manufacturer be consulted first to determine feasibility or will it require a new air compressor specifically designed for steam turbines?

What would be costs to replace 250hp motor? What extra controls are needed? Also, I would assume maintenance costs for turbine would be a lot more compared to motor. Any idea costs for this?
Category: Steam and Thermal Systems

In safety relief valves, is the relieving media steam?
For safety relief valves used for water thermal expansion, would the relieving media be considered steam? Would water in thermal relief, operating at 100 F and the relief valve setting at 150 psig at 373 F, relieve as steam? Or would this have to be considered 2-phase flow? There is always confusion as to what the relieving characteristics are — water, water vapor or steam.
Category: Steam and Thermal Systems

Have you ever heard of steam-vapor recompression to recover vent steam?
Have you ever heard of steam-vapor recompression to recover vent steam and recompress back to usable low-pressure level? Is it really practical to do so? And what type of compressor (or ejector) is suitable for the steam recompression?
Category: Steam and Thermal Systems

How do you define steam?
Under what conditions (temperature, pressure, CA, etc.) is steam called low pressure steam, medium pressure steam, high pressure steam, saturated steam, superheated steam, and condensed form of steam? What is the suggested pipe material for the same with minimum thickness.
Category: Steam and Thermal Systems

Reusing Condensate as Boiler Feed Water
In some projects, condensate is being recovered from LP steam headers and utility stations using steam traps. (This condensate is collected in condensate pot and reused as boiler feed water.) But this condensate recovery is done only for steam headers and utility stations located at 4.8m lvl from grade or higher. This is not done for utility stations at grade lvl. The condensate from the same is just thrown out. What is the reason or base to decide the 4.8 m level?
Category: Steam and Thermal Systems

Are Full Port Valves Necessary For All Steam Lines?
In case of drip legs from steam, we use full port gate valves. Is it mandatory to take full port valve & butt welded connection for all steam lines?
Category: Steam and Thermal Systems

Reducing stress using looped piping
We are planning to install a pump with a three-inch discharge nozzle to an eight-inch process line. The discharge nozzle, however, will face high stress levels, given the polymer pellet slurry, which has a concentration of 33%, temperatures between 80 and 95 degrees Celsius and pressures of 7 kg/cm2g. To accommodate this, a discharge piping loop has been proposed, which is unconventional for slurry. How can we reduce the stress? Will a flexible pipe piece work?
Category: Steam and Thermal Systems

Establishing centrifugal compressor discharge design pressure
How do I establish centrifugal compressor discharge design pressure? Can we arbitrarily add pressure to compressor maximum operating pressure to establish the design pressure of downstream piping and equipment? In the case of pumps, we take the shut off pressure of the pump as the design pressure of downstream equipment.
Category: Steam and Thermal Systems

Effect on the compressor load if the antisurge valve is open
With a double-acting, single-stage oxygen compressor, if the antisurge valve is open, what will be the effect on the compressor load?
Category: Steam and Thermal Systems

Expansion bellows at pump suction
Why should we use expansion bellows at pump suction and discharge nozzles? Should we use expansion bellows only for hot water pumps or can it be used for chilled water pumps also?
Category: Steam and Thermal Systems