Optimization: Filtration for Processes Inside Refineries

Submitted by Chris Sullivan || Valin Corporation
Proper filtration is one of the most important functions performed inside refineries. Filtration is the removal of contaminants through some type of synthetic, paper, pleated or wound media. The goal of this process is to achieve a specific level of cleanliness. This process sounds simple, but there is a lot to understand about filtration to ensure that it is being conducted properly. Proper filtration has the ability to improve efficiency among several different processes inside refineries. More importantly, improper filtration or lack of filtration can have the opposite effect. If ignored or mismanaged, entire systems can fail, leading to unplanned plant shutdowns that ultimately increase operating costs. Often, plant engineering and maintenance managers do not pay enough attention to the lifespan of the filters installed, and some completely forget that filters have been installed at all.

Which processes inside of a refinery require an element of filtration to remain operating at an optimum level? There are several processes that can benefit strongly from proper filtration. In this article, three processes will be discussed: hydrocracking, hydrotreating and fluidic catalytic cracking (FCC).

The Hydrocracking Process

A hydrocracker takes gasoil and cracks the molecules into distillate and gasoline. Refineries use hydrocrackers to shift from maximum diesel and distillate fuel production in the winter to maximum gasoline and jet fuel production in the summer. This process changes the molecular structure of the substance and literally “cracks off” different chemical compounds to form different products. These products are used as “feed” for other refinery processes to produce petroleum products. A typical cracking unit will consist of one or more tall, thick-walled, bullet-shaped reactors, along with a network of furnaces, heat exchangers and other vessels. There are several different hydrocracking process configurations, and proper filtration can improve the efficiency of all of them.

Filtration plays a significant role in improving the fluid quality within the hydrocracking process. Contaminants should be removed from sour water (H2O), reactor feeds and hydrocracker feeds. While reducing scale buildup in the heat exchangers and heaters for optimal heat transfer, filtration also protects the reactor catalyst to reduce energy and maintenance costs. There are a number of products available on the market designed to be used in filtration throughout the hydrocracking process. Pleated filter cartridges, available in multiple varieties, are used to remove particulates. Liquid coalescers are designed to remove dispersed H2O from hydrocarbons, and filter vessels are used for downstream applications.

If the hydrocracking process is experiencing fouled catalyst, reactor bed plugging, liquid carryover from separators, heat exchanger fouling or H2O and particulate issues in compressors, the process may need tuning with filtration solutions.

The Hydrotreating Process

To desulfurize petrochemical feedstock through catalytic conversion, many refineries use a hydrotreating process. In this process, petrochemical feedstocks and hydrogen (H2) are fed to the hydrotreater at high temperatures and pressures. Typical contaminants that can affect this process include sulfide and feedstock impurities. Both contaminants can have a significant adverse effect on the process’ productivity, making filtration a necessity during this process. The impact is far reaching. Hydrotreating is the most common process in petroleum refineries. In more than 700 refineries around the world, there are more than 1,300 hydrotreating units. In most cases, a refinery will have at least three hydrotreaters: one for naphtha, one for light gasoil, and one for heavy gasoil and/or vacuum gasoil. For the hydrotreating units, product specifications are set to meet plantwide objectives.

Filtration is as critical a component to the hydrotreating process as it is to any process inside a refinery. The fluid quality in the process needs to be protected from the downstream pump, compressors, heater and heat exchanger. By filtering out the damaging particulates, costs decrease. These cost savings come in the form of less maintenance, extension of equipment life and less overall plant downtime.

Filtration solutions can solve reactor and heat exchanger fouling, H2O and particulate incidents in H2 compressors and recycle H2 contamination filtration solutions.

The FCC Process

FCC processes produce high-octane gasoline, a range of gasoils, lube extracts, deasphalted oils and gasoil feedstocks. The FCC process also converts gasoil and residue feedstocks into higher-value products. This process is considered to be one of the most important conversion processes happening in petroleum refineries, so maximizing productivity and avoiding any unplanned interruptions throughout the process is particularly critical. In addition to the costs associated with these interruptions, or the resulting insufficient quantities produced, there are environmental regulations at play, as well. As particulate emissions continue to become increasingly stringent, proper filtration is a way to ensure that a plant is meeting all regulations.

Proper filtration can help if an operator is experiencing a catalyst to fouling, reactor bed pluggage, compressor H2O or particulates, final product solids content issues and process liquid carryover conditions.

FCC, hydrocracking and hydrotreating are a few of the many processes that occur on a regular basis inside refineries where filtration can make a noticeable, quantifiable difference. It is critical to understand the original equipment manufacturers’ (OEMs’) requirements for the various filters installed in the system, and to follow its instructions as it pertains to use and lifecycle. By becoming educated in the filtration techniques for the different processes inside refineries, managers and operators can rest assured that they are taking proper precautions to avoid unnecessary shutdowns due to unfiltered contaminants.

Article featured in Hydrocarbon Processing Magazine
A lesson for me is that I need to involve you earlier in the program.

You were tireless in your support and it will not be forgotten!

Latest from Valin's Blog

The NIST Chemistry WebBook contains a great deal of information regarding the properties of a broad range of chemicals and is helpful for those who deal with chemical processes.In this article, Jon Monsen has outlined the procedure for finding the actual density of a gas using the WebBook.