Sulfuric Acid is the highest volume chemical produced in the world. At first glance many feel the manufacturing process is relatively simple, however there is more complexity than most realize. Much of the complexity comes from attempting operations in a severely corrosive system

Product Application

Liquid Distributors - The key to optimal performance of a tower packing is the liquid distributor. The purpose of the proposed high efficiency acid distributor is to evenly distribute the liquid across the towers cross section, thereby providing optimal liquid vapor contact and reducing the chance of poor performance due to liquid and gas channeling. Knight’s high efficiency design provides a 50%+ open area trough type design with 4+ feed point per square foot offering better distribution of the acid over lower feed point designs. The feed points are also directed feed into the top of the bed via drip tubes to reduce entrained acid loading to the mist eliminators. The Knight High Efficiency Acid Distributor is a result of the knowledge developed by the Koch-Glitsch Inc. organization over their decades of involvement in mass transfer operations. Similar designs have a history of success in a number of mass transfer operations. The high performance FLEXERAMIC® Tower Packing is further enhanced by the use of this type of liquid distributor as packing depth is not needed to further radially distribute the initial acid loading.

 

Dome Support Plate - Another key pinch point in a sulfuric acid tower is the support system for the tower packing. The support structure historically has a low open area due to the requirements for bars, piers or mid-spans. The result is a support device having less than 50% open area before tower packing is installed. Due to the restricted open area, this gas liquid interface at the bottom of the tower can become a source of high pressure drop during operation and in some cases localized flooding may occur. The dome support is self supporting and offers significant increased open area over standard grid bar designs. Mechanically this also reduces the chance that a loss of a bar in the packing support will collapse the whole bed.

 

FLEXERAMIC® Tower Packing - FLEXERAMIC® Tower Packing Technology offers improved operation over saddle dumped packing, the structured tower packing with geometrically arranged corrugated sheets provides uniform gas distribution, resulting in intimate mixing and radial distribution of the liquid and gas streams. This increased efficiency offers improvements in moisture removal from the incoming air. This minimizes the chance for SO3 slip along the absorber wall and more effective contact with the down flowing acid stream. The FLEXERAMIC® Tower in general can provide a 50% or more reduction in pressure drop over the current 3" saddle design. The FLEXERAMIC® Tower Packing has the lowest pressure drop of any ceramic tower packing in the market. FLEXERAMIC® Tower Packing has significantly more open area and lower liquid hold up than saddle tower packing. This reduces the possibility of sulfate buildup in the packed bed resulting in longer lower pressure drop operation. The structured tower packing also offers mechanical advantages over the random saddles. The structured packing does not settle like the random dump type, where the bed density increases due to breakage and bed movement. This again provides the customer. with long term operational savings with a longer lower pressure drop operation

 

	FLEXISADDLEÔ Tower Packing - We offer a competitive line of quality ceramic stoneware and porcelain saddles.
	3" LPD FLEXISADDLEÔ Tower Packing - This is a special saddle design offering higher capacity and lower pressure drop. The performance is not as great as provided in FLEXERAMIC® Tower Packing.
	Lining Systems - The lining systems offered by Koch are more than just bricks and mortar, but a custom designed system to meet the corrosion needs of the customer. The complete and durable lining system proposed is designed by Knight engineers to meet the needs of your process. The system is carefully engineered for the correct combination of Red Shale Type III, KNIGHT-WARE® acid proof brick compositions with ACIDSIL™ or mortar and our premier PYROFLEX® acid proof sheet membrane to provide PCS with years of low maintenance operation. Once designed, the installation is by Knight personnel to maintain the level of quality and performance engineered into the lining system. The key to our low maintenance reliable lining system is the PYROFLEX® Membrane. This carbon based cross linking polymer is fused to the vessel wall providing a homogeneous barrier impervious to acid penetration. As additional protection, a Teflon overlay is added over the Pyroflex Membrane. The PYROFLEX membrane remains flexible and does not dry out or become embrittled over time as other polymer based mastics. It is the inelastic nature of other membranes that create maintenance problems in the future. As other membrane's age and become more rigid, the expansion and contraction of the vessel and the brick lining cause other mastics to crack, opening pathways for the acid to contact the vessel wall. As corrosion starts, these rigid mastics detach from the vessel wall exposing more area to corrosion. PYROFLEX Membrane’s flexible characteristics allow it to act as an expansion joint between the brick lining and the steel shell, maintaining a continuous barrier over time. This membrane is successfully installed in hundreds of vessels in acid service, some of which have service lives of over 40 years. The membrane is covered with red shale bricks with our Acidsil Mortar.

 

For More Information:

 

Acid Proof Construction

 

Paul Sims: Email: Paul.Sims@kochknight.com