Precision Combustion, Inc. (PCI) is developing a low-emission, propane-fueled, direct-fired steam generator tool for soil disinfestation. This tool replaces pre-planting chemical fumigant applications for pathogen, pest and weed control.

USDA-funded, field-deployable integration

Backed by USDA-NIFA SBIR awards (Phase I and II), PCI is developing a compact, high-heat-rate catalytic combustor steam generator for integration into a mobile, tractor-pulled soil sterilization system. PCI seeks to partnered with specialty agricultural-equipment manufacturer, grower, or soil-treatment teams to build a full-scale prototype and support field trails timed to planting seasons in a next phase of the effort.

SBIR Program objectives, focused on organic berry crops, included achieving costs at or below methyl bromide, aligning the tool with real production economics beyond lab performance.

Safe and effective

Steam has long been known as a highly effective method to control insects, nematodes and other pathogens and weeds. Up until now it has not been possible to do so in a practical, cost effective manner for large acreage applications. The ability to safely control soil pests, weeds, and pathogens with steam, without the need for toxic fumigants, will enable effective cultivation of agricultural lands while eliminating or reducing food, worker, and surrounding non-farm area exposure to hazardous chemicals. Specifically, with respect to organic produce, our method for soil disinfestation with steam will improve yields and quality while enabling growers to maintain their organic certification.

Designed to overcome conventional limits

The product builds upon our extensive experience in catalytic combustors. Utilizing readily available propane or natural gas as a fuel source, water is passed through a chamber containing a proprietary catalyst bed which, in turn, generates large volumes of steam. This steam is conveyed to the soil via an applicator that controllably delivers the steam at an appropriate temperature and depth, thereby raising the soil temperature to a level that destroys pathogens and weeds.

Earlier field steam applicators (steam rake/blade) typically managed ~0.5 acre/day and remained bulky, slow, and costly, with demanding water quality. PCI’s approach targets much higher application rates in a compact package, uses on-farm propane or natural gas and available field/untreated well water, and is engineered for economical, large-acreage operation.

Efficiency, emissions, and water use

PCI’s catalytic combustor operates on propane, but can be adapted to other fuel sources. It does not require treated water, unlike conventional boilers. Catalytic combustors are much more efficient than boilers in converting the energy of the fuel into usable steam. In addition to being more cost effective, emissions are significantly lower. Our product is targeted for integration with a self-propelled or tractor-pulled compact machine for high-rate high-efficiency steam treatment of planting beds and soils, suitable for large scale agricultural use. We can reach greater than 95% fuel-energy efficiency, very low emissions from a lean catalytic combustor (measured <10 ppm CO and <10 ppm NOx), and operation on untreated well water, key advantages for a mobile system capable of treating 5-10 acres per day.

Summarizing the advantages of PCI’s catalytic steam generation technology as applied to soil disinfestation: Advantages of PCI’s Catalytic Steam Generation Technology