Clean Burn, Part 2
Thomas Koziorowski, Probat
By Jenny Neill
Given the changing landscape of air quality standards, how do two of the largest coffee roasting equipment supply companies provide flexible solutions for customers?
The May-June issue of STiR Tea & Coffee focused on how changing regulations and consequent application of new air quality standards may impact smaller coffee roasting operations. In Clean Burn, Part Two, STiR tackles that same issue from the perspective of how manufacturers work to provide solutions for roasters of all sizes all over the world. This time, STiR revisits emissions control via exhaust gas treatment systems from two of the biggest roasting equipment manufacturers. In a future report, STiR will delve into the challenges of dealing with emerging low and ultra-low NOx standards.
German-based Probat has a long history of manufacturing roasting equipment that stretches back to the mid-19th century. Neuhaus-Neotec is a relative newcomer having been founded in 1931 as a company that produced milling equipment. Both companies have designed and made machines used in coffee roasting and processing plants for decades. With such longevity in the market comes expertise in adapting to regulatory change. Let’s take a look at how each company helps customers adjust to changes in exhaust standards for roasters.
Probat’s modular approach
Thomas Koziorowski, director of product technology/r&d at Probat, said the company designs its products and product components with modularity in mind. The rationale for this is to enable a customer to be able to change one or two parts instead of having to buy whole new systems if regulations change.
Koziorowski said, “We have to [take that possibility of change into account when we] model our environmental system to give our customers the possibility to update and upgrade their systems. When the regulations have changed, [we want the roaster to have] the possibility that he only has to change one or two parts but all the other things could be used still.”
Other factors matter, too, when it comes to making a decision about which equipment will best address the needs of a roaster customer.
Karl Schmidt, president of Probat Burns, explained what sort of questions he would ask a prospective customer: “Is the area residential? Is it in a mall? Near a plaza? Is there a school around? Is there a kindergarten? All of these things come into play when recommending an air pollution remediation device.”
Koziorowski agreed that it is important to model the environmental aspects of the system carefully because Probat equipment lasts a long time.
He said, “The problem is that our roasting equipment has a lifespan of 30, 40, 50 years in operation. When you’re taking a look at emissions regulations, you find changes every four or five years.”
All those questions Schmidt would ask may well become the basis for more or less stringent standards depending where in the world a company is based.
Probat, of course, offers components to address the needs of coffee roasters of any size. The RV, an afterburner, works well for customers in countries where emission regulation standards are quite low. It heats exhaust air to a temperature of approximately 450°C by means of an additional blower burner. The RVS, an extended afterburner, includes an additional blower burner which increases the roasting exhaust air temperature to about 750°C. An optional temperature stage control system allows operators greater control over the average operating temperature.
The TVR line of thermal pre-cleaners is comparable to that of the RV afterburner. The base model (TVR/KEG) can be fitted later with a catalytic afterburner (NVK, making the combination of TVR/NVK as depicted in the chart on the next page). The thermal pre-cleaner can also be equipped with a catalyzer casing instead of a cone, which prepares the system for a later retrofitting of catalyzer cassettes. In this case, a catalytic afterburning takes place after the thermal pre-cleaning.
If a roaster in the EU was trying to make the decision between the style of using a thermal afterburner with cone versus a cassette catalyzer and no changes in air quality standards were expected, Koziorowski suggested the afterburner with a cone is more cost effective.
Specifically, he said, “The catalyzer cassette materials will be, for example, palladium, a material which is not cheap so the investment for that is higher but you reach lower emission levels with it.”
For companies needing to sustain a high volume throughput, both Koziorowski and Schmidt recommend taking a look at the Proforte. This FRTO (flameless, regenerative, thermal oxidizer) treats and takes the roasting exhaust gases through a ceramic bed with interior temperatures of 900 to 1,100°C. The ceramic bed maintains its temperature because the flow of exhaust gas into the system is cyclically reversed.
The modularity of Probat’s product line allows roasters flexibility in making a decision about how best to address air quality standards. However, Schmidt said, “For a large corporation, based on the volume of air [pollutants] to be destroyed, I would recommend RTO. It is not an economical solution for a small roaster.”
Neuhaus-Neotec’s customer-centric focus
Neuhaus-Neotec designs its equipment for large companies so that about 90-95% of the roaster’s air is routed in a circle.
Neuhaus also offers solutions that utilize the exhaust air of the roaster to pre-heat the green coffee, thus saving up to 25% of the energy and increasing the roaster’s efficiency by up to 25% with the same energy use. (See illustration at left)
Leon Heisterüber, who heads process engineering, research & development at the company, said, “Compliance with the limits set by the new technical instructions on air quality control (guideline 3892 of the Association of German Engineers) or also with the stricter limits of other countries (Switzerland, Italy, etc.) is no problem for Neuhaus Neotec. The know-how is not just restricted to the coffee market but comes also from other industrial sectors such as the chemical, pharmaceutical, energy, or waste incineration so we can always offer our customers the best possible solution.”
According to Heisterüber, special requirements for emission limits are the norm in Scandinavia; often, not only quality but also the quantity of exhaust gases in a region must be assessed. California also has some of the strictest environmental rules in the United States. For these reasons, Neuhaus Neotec utilizes RTO (regenerative thermal oxidation) in large-scale plants located in these countries. Heisterüber suggested even plants operating 24-hours a day, five days a week would benefit from this technology.
Heisterüber said, “Generally, it should be remembered that the investment costs per cubic meter of purified exhaust gas become lower as the plant gets bigger.”
This means the more expensive solutions such as an RTO and a biowasher have a reasonable return-on-investment for larger rather than smaller plants.
For retail-roaster businesses, Neuhaus offers turnkey post-treatment systems for exhaust gas. These allow coffee businesses to operate in densely populated areas where especially strict requirements are imposed. These systems typically consist of one electric heater battery with an oxidation catalyst installed downstream.
“Naturally, the question remains what solution to apply, and this will always depend on the respective conditions and purity requirements in the destination and the customer’s wishes.”