Skip to content

When Performing Capital Improvements, Also Consider Your Catalytic Converter

May 15, 2013

When capital improvements are being discussed or funded for equipment that does contain a catalytic converter, facilities managers are wise to include an evaluation of the possible benefits of replacing or upgrading their catalytic air emissions control devices.  For those managers who are savvy enough to consider the catalytic converter as part of their improvement projects, this is an item where cost savings can be realized.  Certainly not all systems warrant replacement of the catalysts, but unless the system is appropriately evaluated managers could be missing an opportunity to install a catalyst that includes the best possible design for their specific application.  Among the possible benefits at stake are documentation of current emissions conversion efficiencies, backpressure improvements, and lower operating costs.

This catalyst improvement scenario is quite common, and is exactly what happened for a well-known US-based engine manufacturer.  As part of a redesign project of a power generation system used in a recreational marine application, the catalytic converter system was included in their product improvement project.  The end result was that both cost and performance improvements were identified for the catalyst.

A similar experience occurred for a public electric generation utility company that needed to make engine improvements to address RICE NESHAPs regulatory requirements.  In this instance, the new catalysts were able to be designed to be more efficient and less expensive than the replaced catalysts on a comparative volumetric basis.

In both of these examples, the selected catalyst manufacturing firm was able to evaluate and test the existing catalyst system, which then facilitated the design of a proportionately less expensive catalyst that also included the provision of supporting data that the new catalyst would satisfy regulatory objectives.  Furthermore, as part of value-added service provided by the catalyst manufacturer, the referenced public electric generation utility company was able to receive money back for a portion of the recovered precious metal from their replaced catalyst units.

Advertisements

Catalyst Cleaning

March 29, 2013

Earlier this year, we issued a blog entitled ‘Catalyst Recycling’ that contained an overview of the basics and economic incentives involved with recycling your spent catalyst blocks. As a companion posting to that Catalyst Recycling blog, it is appropriate that we touch upon the subject of cleaning catalysts as a way to prolong a catalyst’s useful life. If your catalyst has been adversely affected with removable dirt, debris or other masking agents, catalyst cleaning can be a cost-effective way to extend the functionality of that catalyst before incurring the expense of catalyst replacement. However, as expounded upon below, it is advised that the catalyst owner have a high level of familiarity with his/her system in which the catalyst is operating, as well as a solid understanding of catalyst basics before making the decision to have catalysts cleaned.

 

Let’s take a quick step backwards. All operational catalysts are exposed to physical, chemical and thermal mediums that lead to varying degrees of catalyst deactivation. Deactivation is simply the process of lessening the catalyst’s ability to assist in the chemical reactions it was engineered to perform. Deactivation is not at all an all-or-nothing proposition, rather it is a matter of degree [follow links for a detailed explanation of Catalyst Deactivation – (see ‘Catalyst Deactivation Part 1’ and ‘Catalyst Deactivation Part 2’). The deactivation usually is the result of: (a) chemical poisoning; (b) masking; and/or, (c) thermal sintering. Certain types of deactivation can be reversed, while others cannot. For those deactivation processes that are reversible, this is where catalyst cleaning becomes relevant. More specifically, masking and certain chemical poisons can be substantially corrected with cleaning. However, certain other chemical poisons, as well as thermal sintering do result in permanent catalyst damage, for which cleaning does not help.

 

When considering the cost-benefit variables of whether to clean or replace a catalyst unit, the catalyst owner and the company that provides the cleaning service should qualify the below listed parameters as part of the overall decision making process. These variables can not only assist in estimating the target effectiveness of the cleaning, but they can direct the evaluation to which types of cleaning techniques should be considered. In the end, the decision to conduct cleaning versus replacement will be a judgment call. It is also important to note that cleaning is never expected to render the catalyst to its’ original new condition.

 

Parameter

Reason

The size of the catalyst unit Cleaning larger units typically will have a greater cost-benefit.
The catalyst application Weigh factors such as operator knowledge, the applicability of supporting regulations, duration of engine run times, whether unit’s operational environment remains constant or is dynamic, etc.
Types and quantities of contaminants Evaluate whether cleaning will be effective.

 

Age of the catalyst unit Newer units typically will have a greater cost-benefit.
Previous cleaning applications Was previous cleaning successful? Also, each successive cleaning will have diminishing effectiveness.

 

There are different methods of catalyst cleaning. Most methods are specific to the root cause of why the cleaning is warranted, but also some companies only offer certain cleaning processes. It is recommended that the catalyst owner understand why one cleaning technique is being recommended over another. The common methods of cleaning catalysts include, but are not limited to:

 

Cleaning Method

Best For

Low pressure air (steady state and/or pulsating) Good for removing loose debris & sediment.
Soaking in mild detergent or acid/base solution Good for poisons and other compounds ionically adhered to surface of the catalyst. Also will remove loose debris & sediment.
Thermal (heating) treatment Good for burning fuel deposits such as soot and unburned hydrocarbons.

 

At Hypercat ACP, when it makes sense to do so, our cleaning services include a core testing program, by which a 1-inch core sample is removed from the catalyst. This core sample is then tested for performance both before and after the cleaning is conducted. The results of the core testing program will help quantify the expected degree of effectiveness the cleaning will achieve for the entire catalyst. Thus, the owner will have additional information to assist in the decision of cleaning the entire catalyst or having it replaced.

RICE NESHAP Amendments

February 28, 2013

With the looming May 03, 2013 Compliance Date for certain existing Compression Ignition (CI) engines, RICE NESHAP* regulations is a topic currently being discussed in many business and industry groups. There are literally tens-of-thousands of engine owners/operators who will be subject to the rule’s Compliance Date implementation and, among other required upgrade activities, will be installing new catalysts to keep their engines operating in compliance. What’s more, in January 2013 the USEPA* finalized its amendments to NESHAP regulations as they apply to reciprocating internal combustion engines (RICE), both Compression Ignition (CI) engines and Spark Ignition (SI) engines. In this month’s blog, we will briefly outline the recent amendments to NESHAP, and provide resources to allow our readers to learn more about the rule and its January 2013 amendments.

By way of background, in the universe of engines, an engine’s use is classified as being either ‘mobile’ or ‘stationary.’ Under each of those headings are several sub-classifications to further identify the use and applicability of engines. As an example, for mobile engines an important distinction is whether that engine is mounted in motor vehicle for over-road use, or in non-road equipment such as construction machinery, recreational vehicles and outdoor power equipment. Locomotive, aviation and marine are considered their own types of mobile engine applications.

RICE NESHAP applies to existing, new and reconstructed stationary engines, both CI and SI. Stationary engines are classified as such when they are not used in a motor vehicle and are not considered a ‘non-road’ engine, such as tractors, bulldozers, mobile lifts, lawnmowers, skid-mounted portable engines, etc. Common applications of stationary engines are electric power generation, oil & gas rig and pump operation, irrigation pump operation, and miscellaneous industrial functions. According to statistics generated by the USEPA, there exists an estimated 1.5 million stationary engines, 78% of which are CI. The sizes of these stationary engines range from 1 kW to 10 kW, and approximately 60% are used for emergency power generation.

NESHAP was promulgated by the USEPA in March 2010 and August 2010 for CI RICE and SI RICE, respectively. Subsequent to the publication of these rules, various affected parties submitted petitions, complaints and other types of communications regarding issues identified within the rules, and the USEPA agreed to take into consideration the issues raised for the purpose of possibly creating amendments to the rule. In January 2013, the USEPA* finalized its amendments to the NESHAP regulations. The following summarizes the categories of change created by the amendments. An actual summary of the changes is considered too lengthy for the purpose of this blog:

  • Emergency engines
  • Engines scheduled to be replaced in the next few years due to state or local rules and certain engines installed in 2006
  • Stationary CI engines on offshore vessels on the Outer Continental Shelf
  • Area Source Stationary SI engines > 500 hp
  • Compliance alternative for formaldehyde emissions
  • Remote areas of Alaska

According to the USEPA*, these amendments will result in the reduction of capital and annual costs of the original 2010 rules by an estimated $287M and $139M, respectively. The amended rules are estimated to eliminate from the cumulative exhaust mass being discharged annually in the US: (a) 2,800 tons per year of listed hazardous air pollutants; (b) 36,000 tpy* of carbon monoxide; (c) 2,800 tpy of particulate matter; (d) 9,600 tpy of nitrogen oxides (NOx); and, (e) 36,000 tpy of volatile organic compounds. For more information, including a copy of the final RICE NESHAP rule and fact sheets summarizing the rule, you can go to: www.epa.gov/ttn/atw/rice/ricepg.html.

*

RICE – Reciprocating Internal Combustion Engine

NESHAP – National Emission Standards for Hazardous Air Pollutants

USEPA – United States Environmental Protection Agency

CI – Compression Ignition (typically fueled by diesel or biodiesel)

SI – Spark Ignition (typically fueled by gasoline

tpy – Tons per Year

Catalyst Recycling

January 31, 2013

You will recall from our “Catalyst 101” blog that catalysts frequently are loaded with Platinum Group Metals [PGMs] such as Platinum, Palladium and Rhodium, and that these precious metals are not consumed as part of the chemical reactions that the catalysts enhance. As a result, what can happen is that—unwittingly—used and/or spent catalyst materials are frequently being discarded as waste without consideration for the monetary value of the precious metals that can be recovered. As if to add insult to injury, there are also plenty of entities who pay to have their used and spent catalysts hauled away for disposal.

Hypercat ACP’s sister company—Recycalytics—specializes in the extraction of PGM values from ceramic and metallic catalyzed substrate elements, using proprietary and environmentally friendly technology. Catalyst materials accepted for recycling include catalytic converters from cars, diesel particulate filters [DPFs] from trucks and buses, as well as ceramic and metallic monolith units from industrial and manufacturing emission control devices. Then, using a proprietary statistical model, Recycalytics can rapidly and accurately determine the PGM content on any catalyst surface. From that information, based on prevailing world market prices for the applicable precious metals, in exchange for the sold spent catalyst customers can either receive an immediate cash settlement or apply the cash value towards the purchase of replacement catalyst(s).

When done appropriately and fairly, catalyst recycling is a proverbial “Win / Win” for those participating. And when working with Recycalytics, parties with catalysts to recycle are able to transact the business with no real risks. Here’s how it works:

Scrap pick-up and transportation is arranged by Recycalytics. If helpful, Recycalytics can also supply packaging materials to facilitate the transportation. On a quick turn-around basis, a purchase price for the spent catalyst(s) is calculated and reported to the seller. If the purchase price is acceptable, then the purchase price is given or credited on the spot. If the purchase price is not approved, then the customer’s catalyst materials are returned at the expense of Recycalytics. Recycalytics can be contacted at www.recycalytics.com, or through the Recycalytics links found on the Hypercat APC website.

Lastly, cleaning used catalysts is also a service available for consideration. For example, Diesel Particulate Filters [DPFs] are emission control devices that clean air emitted by diesel engines found in trucks, buses and heavy equipment. DPF cleaning services are fairly common, and proper cleaning can extend the life of newer units to help them maintain their efficacy. We’ll discuss these cleaning options in greater detail in future Hypercat ACP blogs.

Traditional Catalyst Loading vs. Nanotechnology

December 17, 2012

In last month’s blog, we provided an overview of how to develop and select the catalyst needed for your application.  This month, we’d like to expand on that same concept by contrasting traditional catalyst loading versus use of nanotechnology loading.

When we speak of traditional catalyst loading, we are referring to standard but proprietary manufacturing methods for optimal Platinum Group Metal (PGM) dispersion with oxide supports to maximize precision metal distribution over the entire catalyst.  Under the banner of traditional catalyst loading, there are numerous combinations and ratios of washcoat materials and PGM, as well there are several techniques for applying these materials to the applicable substrate products.  As part of traditional catalyst loading, the catalyst solutions can be applied to the substrate in one or more layers, and can even be directed to a specific ‘zone’ of the catalyst.  For example, the front portion of a catalyst can be loaded differently than the back portion of the catalyst.  These choices of various traditional catalyst loading options are all formulated to meet the specific use and goals of the catalyst objectives.  For every application there is an optimal loading.

Through nanomaterial science application, the washcoat and PGM components can be engineered and made effective at the nanotechnology level.  The National Nanotechnology Initiative (a US government-sponsored cooperative) defines nanotechnology as the understanding and control of materials with dimensions between 1 and 100 nanometers.  Certain physical, chemical and biological properties do occur at the nanoscale differently than they occur in larger scale materials.

The use of nanotechnology offers improved catalytic performance characteristics such as lower light-off temperatures and enhanced durability.  These improvements are a function of the fact that the attachment of the washcoat and PGM particles is more optimal.  Moreover, these improvements are typically offered on parts so that lower effective PGM loadings are achieved, resulting in certain cost savings.  Lower PGM loadings are possible because the particles are custom engineered to have optimized geometries and positioning at the catalyst surfaces.  They also behave differently at the quantum level which further enhances their catalytic properties.

Nanotechnology isn’t right for every application. Even though less precious metal is needed, the technology is still expensive.  As loadings increase, it becomes more cost effective to utilize nanotechnology.  At the end of the day, nanotechnology gives us an extra set of tools in our tool belt to meet our customers’ needs.

Catalyst Selection

November 30, 2012

There is a wealth of information required to design a catalyst system. Much of this information can be identified during the process of outlining what is driving your catalyst needs. Application-specific questions like, what are the emissions limits?, are there any catalyst poisons in the exhaust?, and, what is the maximum backpressure that the system can handle?, are important questions to ask. The answers to these types of questions, along with accuracy of the process parameters, will help to ensure that the catalyst design will achieve the emissions’ goals and requirements.

 

Hypercat ACP will evaluate the available engine/combustion unit data and will develop a conceptual model of what the catalyst system will entail, its performance goals, and all limiting factors such as physical space constraints, operational safety concerns, and other components of the overall system that may influence the catalyst design and/or performance. Some of the resources that may be used to formulate a catalyst that balances the emission reduction requirements and the overall system cost include historical guidelines, internally-developed light-off curves, and application-specific exothermic and pressure drop calculations.

 

Working with a catalyst supplier who has the ability to actually test a catalyst under the simulated conditions of operation is a great advantage over just trying to predict expected performance from other system designs. Tuning of the oxygen levels and tuning of the Platinum Group Metals [PGM] levels and type(s) are all things that can be quickly tested without a huge cost. At the project’s conclusion, this could save thousands of dollars on the overall design.

 

In the end, when catalyst performance is critical to your engine or industrial process application, there is value in knowing the experience and capabilities of the company supplying your catalyst. This value should be realized through the catalyst design phase, catalyst performance phase, and catalyst warranty. When a catalyst supplier takes the interest and time to ask proper questions and formulate a test plan to prescreen the catalyst before producing the full scale unit, it translates into the final catalyst system being designed to fit the needs of the application for which it will be installed. For many catalyst applications, the age old adage “an ounce of measure is worth a pound of cure” holds entirely true. Alternatively, without this skill set the catalyst manufacturer is left to make several conservative assumptions which usually result in the end user (the catalyst purchaser) buying more PGM-coated catalyst than is necessary for their particular emissions needs.

Catalyst Components – Substrate

October 31, 2012

The substrate is, in essence, the core of a catalytic converter. A catalytic washcoat is what does the job of filtering the exhaust that passes through the converter. The substrate is what that washcoat clings to, which is why it’s often referred to as the catalyst support. As we mentioned in our earlier blogs, the key to catalyst filtration is surface area. The more geometric surface area that’s exposed, the more area exists for exhaust to contact. To get more surface area out of your washcoat, you first need a substrate with a geometrically high surface area. In addition to acting as a catalyst support, the function of the substrate is to allow the applicable volume of exhaust gas to pass through while minimizing flow backpressure.

In the past, catalytic substrate was typically comprised of pellets. While some catalysts still make use of this form, today most substrates take the form of a ceramic or a metallic foil. These can be applied in many shapes, sizes, lengths and cell densities. Each catalytic converter is designed for a specific application. In accordance with this, the substrate is sized—both its volume and its cell density—specific to the engine and associated exhaust application.

Ceramic and metallic foil substrates contain numerous small parallel flow-through channels known as cells through which exhaust passes. Cell density is an important distinguishing feature between substrates (measured as cells per square inch [cpsi]).  The greater the cell density, the greater the available surface area on the substrate part.

The substrate can also be comprised of a wire mesh product. Wire mesh is typically used when an exhaust filtering property for particulate matter is desired. Thus, where a ceramic or metallic foil substrate is designed to control or minimize turbulent exhaust air flow, a wire mesh product is designed to take advantage of turbulent exhaust air flow to facilitate exhaust filtration. Depending upon the customer’s objectives, the wire mesh may or may not be coated with catalytic washcoat.

You can’t have a catalyst without a substrate. It is the base that the rest of the catalyst is built upon.

Hypercat ACP’s long-term partnership with various vendors allows us to offer an array of catalytic substrate products. To find out more about these products, visit our website: http://www.hypercat-acp.com/catalyst-substrate.html

%d bloggers like this: