HRS Heat Exchangers has received two orders for thermal solutions for sludge and waste-food applications for a major environmental company in the United Kingdom.

The London-based exchanger maker will provide double-tube heat exchangers for cooling sewage sludge after a thermal hydrolysis process, an energy-efficient process of heating sludge under high temperature and pressure (usually 284 to 338°F [140 to 170°C]). The thermal processing increases the gas load, producing more biogas that can be used to create power and heat. During the process, the sludge also is stabilized and disinfected.

According to HRS, the double-tube heat exchanger design makes it easier to work with fluids that contain particles without blocking the product flow.

Another significant order allows HRS to supply a turnkey package to continuously pasteurize mixed food waste to the standards set for animal byproducts regulation (ABPR). Controlled by the European Union (EU), the main aim of the ABPR is to prevent animal byproducts from presenting a risk to animal or public health through the transmission of disease.

HRS received an order to install a turnkey system utilizing corrugated double-tube heat exchangers in a thermal regeneration loop to heat incoming raw waste with hot pasteurized sludge. The product is further heated to its pasteurization temperature before being held for an hour to comply with the ABPR regulations.

As part of a thermal regeneration loop, HRS corrugated DTR heat exchangers will heat incoming raw waste with hot pasteurized sludge. The food waste goes through three sequenced tanks as part of the continuous batch process. The product then passes through the thermal regeneration heat exchanger, where it is cooled by the incoming raw waste before going to the digesters.