Happy New Year from Process Systems & Design

With 2017 coming to a close, all of us at Process Systems & Design wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.

Sludge Removal by Wastewater Treatment Clarifiers

As the video below points out, dirty wastewater enters from the center of the clarifier and very slowly makes its way towards the outside where the water spills over the weir. During that retention period, the solids have enough time to settle to the bottom, where they're later picked up as sludge, and the clarified, or cleaner water, spills out along the edge. Clarifiers are made in many different shapes and sizes all work on basically the same principle. The sludge is then processed to remove water, be neutralized biologically, and reduce the levels of pathogenic organisms.

Beneficial uses of treated municipal wastewater sludges on land include agriculture and silviculture uses; application to parks, golf courses, and public lands; use in reclaiming low quality or spoiled lands; and use as landfill cover or fill material. Disposal on land includes landfilling and permanent storage of dewatered sludge or sludge incinerator ash in lagoons or piles.

Pultruded FRP Composites as an Alternate to Steel

Pultruded FRP suspendible roof structure.

Pultrusion is a term that describes a manufacturing process for producing continuous lengths of FRP (fiberglass reinforced plastic) where reinforcing fibers are saturated with resin and pulled through a heated die to form a part. The result is a straight, constant cross-section profiles similar to standard steel shapes.

Pultruded composite sections can be used to design and install lightweight, corrosion-resistant and electrically non-conductive alternatives to steel structures, particularly where speed and ease of construction are important. Pultruded FRP has performance characteristics similar to other construction metals, but unlike steel, it is EM/RF transparent and doesn’t disrupt equipment signals.

Benefits:

• Pound-for-pound stronger than steel.
• Comparable structural performance to other metals such as aluminum, but without the conductivity, corrosion or impact limitations. 
• Can be painted, coated or pigmented during manufacture for little-to-no maintenance in highly aggressive environments
• Designed for UV performance
• Enables rapid cleaning with aggressive solvents at high pressures
• Meets industry requirements for durability, smoothness, absorbency, color, corrosion resistance and washability

Typical Uses:

• Structural profiles and plates
• Decking and planking
• Platforms, stairs, ladders and cages
• Handrails, guarding and kickplates
• Grating and gridmesh
• Bridge components
• Structural building panels
• Sheet piling and round pile
• Containment systems
• Ballistic and storm panels
• Connection hardware

Pultruded FRP composites are ideal for structural elements where a strong, lightweight material is needed; corrosion is a concern for steel or other metals; RF permeability is needed; and low thermal or electrical conductivity is important.

To discuss using pultruded FRP composites on your next project, contact Process Systems Design by calling (410) 861-6437 or visit https://www.processsystemsdesign.com.

Consider the Possibility of Constituent By-products in Your Process Heating System

It is estimated that over 7,000 TBtu/year (Trillion British Thermal Units) of energy is used for process heating by the manufacturing sector in the United States. This energy is in the form of fuels—mostly natural gas with some coal or other fuels—and steam generated using fuels such as natural gas, coal, by-product fuels, and some others.

Combustion of these fuels results in the release of heat, which is used for process heating, and in the generation of combustion products that are discharged from the heating system. All major US industries use heating equipment such as furnaces, ovens, heaters, kilns, and dryers. The hot exhaust gases from this equipment, after providing the necessary process heat, are discharged into the atmosphere through stacks.  The temperature of the exhaust gases discharged into the atmosphere from heating equipment depends on the process temperature and whether a waste heat recovery (WHR) system is used to reduce the exhaust gas temperature. The temperature of discharged gases varies from as low as 200°F to as high as 3000°F.

Combustion products themselves, generated from well-designed and well-operated burners using gaseous and light liquid fuels, are relatively clean and do not contain particles or condensable components that may require “cleanup” before discharge into the atmosphere. However, during the heating process, the combustion products may react or mix with the product being heated and may pick up constituents such as reactive gases, liquid vapors, volatiles from low-melting-temperature solid materials, particulates, condensable materials, and the like.

Some or all of these constituents, particularly at high temperatures, may react with materials used in the construction of downstream heat WHR equipment and create significant problems.

Potential Problems:

• Chemical reaction of exhaust gases and their solid or vapor content with the materials used in the WHR equipment.
• Deposit of particulates in or on surfaces of WHR equipment.
• Condensation of organics such as tars and inorganic vapors such as zinc oxides and boron on heat exchanger surfaces.
• Erosion of heat exchanger components by the solids in the exhaust gases. 

Many of these problems are compounded by the high temperature of the exhaust gases, uneven flow patterns of the hot gases inside the heat exchanger, and operating variations such as frequent heating and cooling of the heat exchanger.

Dealing with industrial heating processes in which the exhaust gases are at high temperatures, or that contain all reactive constituents, or can be considered as harsh or contaminated are important considerations for the process engineer.  If unsure, professional advice from knowledgeable consultants should be sought to optimize the heating system. To discuss any process heating requirement you may have, contact Process Systems & Design at https://www.processsystemsdesign.com or by calling (410) 861-6437.