Fixed bed reactors, where the fluid flow passes through a stationary bed of catalyst or adsorbent, are widely used in refining, petrochemical, natural gas and chemical plant processes. In these vessels, it is essential to prevent migration of the catalyst or adsorbent through the bottom screens or distributor/collector. Inert ceramic bed support media is loaded at the bottom and top of these reactors to support and maintain catalysts in place.
In such applications, proper size selection and grading of the bed support is critical to prevent catalyst migration. Migration of the catalyst in a reactor can result in decreased performance and elevated pressure drop, which diminish the efficiency and service life of the reactor.
Likewise, the selection and configuration of the bed support can influence pressure drop in the reactor. Lower pressure drop through the support media reduces energy requirements and benefits overall reactor performance.
It is incumbent upon the chemical engineer to select the bed support media and configuration within the reactor that both prevent catalyst migration and minimize pressure drop.
Denstone® support media, properly graded by size and layered in the bottom of your vessel, keeps pressure drop low, prevents migration of the catalyst bed and enables the catalyst to achieve optimal performance (Figure 1 at right).
Saint-Gobain NorPro, the industry leader in support media, has developed Size Selection Guide and Pressure Drop Estimator tools that help optimize the selection and configuration of Denstone bed support media.
Denstone support media are manufactured in a wide range of sizes to meet the needs of each application. Selecting the optimum support media size gradation and layering configuration are critical for optimizing catalyst life and performance. Saint-Gobain has put the design power in the engineers’ hands with their Denstone size selection guide and pressure drop estimator tools, which are both available on their website.
With the Size Selection Guide, (Figure 1: pictured below) the user can identify the recommended support media layering in their vessel for both Denstone balls and Denstone® deltaP® by simply entering the catalyst diameter, the total height of all bottom support media and bottom screen size opening.
The Pressure Drop Estimator (Figure 2: pictured below) allows the engineer to evaluate various scenarios to determine the optimal configuration for their specific application. This tool lets the user calculate the pressure drop over the Denstone support media based on the reactor conditions. This will also show how Denstone deltaP support media compares with standard balls to help the user choose the best media for the reactor.
Bed support media must withstand severe operating conditions without contaminating or participating in the process. Only an exceptional bed support media will allow the catalyst to achieve optimum performance and service life.
Saint-Gobain NorPro developed Denstone support media over 70 years ago for fixed bed catalyst applications. The Denstone product family includes an extensive range of bed support media, including Denstone 57, Denstone 2000, Denstone deltaP and Denstone 99 support media.
Denstone® 57 balls are used as support in molecular sieve and silica gel dehydration, hydroprocessing and desulfurization. This product provides high thermal shock resistance, and prevents poisoning, contamination and plugging of the catalyst bed.
Denstone® 2000 balls are formulated specifically for demanding environments of hydrocracking processes to provide exceptional reliability and survival through thermal cycling, rapid depressurization, high impacts, compressive forces and high thermal shock.
Denstone® deltaP® bed support media is engineered to require only two layers of support media (Figure 5), which can decrease fill costs, lower pressure drop, simplify reactor loading and reduce the total volume of support media. The additional catalyst or adsorbent enables the user to improve product specifications or increase capacity.
Denstone deltaP media utilizes a unique, engineered shape that improves operational performance by reducing pressure drop through the catalyst bed. On average, there is a 50% pressure drop decrease when using Denstone deltaP media versus traditional support balls.
Denstone® 99 support balls are composed of more than 99% alpha alumina, which makes this product ideal for high temperature and steam applications. It has excellent thermal properties, superior chemical resistance and high strength. The minimal silica content of Denstone 99 support media makes it chemically inert and prevents fouling of the catalyst bed and of downstream equipment.
Saint-Gobain NorPro’s support media technologies have been designed to fit a range of applications while at the same time providing the user with the added security of performance in even the most demanding environments. Denstone media allows the catalyst user to focus on optimizing their catalyst and reactor performance, knowing that the support media will have the same performance every time. The diverse Denstone product family allows customers to choose the right support media to maximize reactor performance.
Use the Size Selection Guide and Pressure Drop Estimator tools to determine the optimum selection of support media for your specific application.