8/20/2019 CASE STUDY: HRS Heat Exchangers help Muntons close the loop

1/2

M

alted ingredients company

Muntons (Stowmarket,

Suffolk) is putting the

nishing touches to its £5.4

million on-site anaerobic

digestion (AD) plant which

will help reduce the rm’s

CO2 emissions from 27,264

to 26,605 tonnes per annum.Integral to the success of the 499 kW facility is a three Tank Batch

Sludge Pasteuriser System with Energy Recovery from HRS

Heat Exchangers, which will help turn up to 80,000 tonnes of

Muntons’ liquid malt waste into quality organic fertiliser (known

as digestate). This will be used on local farmland, helping the

company’s network of growers to produce some of the 250,000

tonnes of barley needed to make Muntons’ malt, around 180,000

tonnes per annum.

Muntons is a company with sustainability at its core and this

project will create a closed loop system, exemplifying the circular

economy. The company became interested in AD after analysis

showed that 60 percent of the carbon footprint of its supply chain

came from the articial fertiliser used by its barley growers. The

rm realised that using its liquid malt waste as feedstock for an

on-site AD plant would not only produce a high quality digestate

for its farmers to use instead of articial fertiliser, it would also cut

3,000 tanker movements per year and generate 25 percent of thesite’s electricity demand.

The digestate will be pasteurised to meet stringent PAS 110

standards using the HRS Heat Exchangers three Tank Batch

system, ensuring that the nal fertiliser is free from plant

pathogens or other biological contaminants. The beauty of the

closed-loop system is that the waste feedstock which is turned into

digestate during the AD process has come only from the processing

of barley. It is then applied to the next barley crops for use in the

factory.

As well as a comprehensive proposal, the Muntons’ team was

impressed by the HRS system, which can save up to 70 percent of

heat required, as well as its ability to run at a half ow rate, shouldthe volume of digestate stock reduce. Additionally, the equipment’s

monitoring feature enables Muntons to track every batch of

digestate back to the feedstock from which it was produced. “The

fact that the HRS system offers batch reporting was also a big

draw; traceability is very important to us,” remarks Lawrence

Howes, Project Engineer at Muntons.

Matt Hale, International Sales Manager at HRS: “For Muntons,

this whole project has been about maximising efciency. Although

they have an abundance of heat, they still wanted to recapture what

they could - our heat exchangers will provide at least 40 percent

heat regeneration.”

The HRS system works on a three tank principle; while one tank

is being lled, the second tank holds the sludge at 70°C at the

same time as the third tank is being emptied (each process lasts

one hour). Waste cooling water from the CHP engine is used to

heat the sludge in corrugated tube-in-tube heat exchangers, which

Muntons is a company withsustainability at its core and thisproject will create a closed loop

system, exemplifying the circular

economy.

HRS Heat Exchangershelp Muntons close the

loop

F CASE STUDY 

CASE STUDY 

66  | December 2015 - Milling and Grain

8/20/2019 CASE STUDY: HRS Heat Exchangers help Muntons close the loop

2/2

is more efcient than heating an entire tank of digestate. HRS has

also incorporated an energy recovery section into the process to

make it even more efcient: energy is transferred from the hotter

(pasteurised) sludge to the colder (unpasteurised) sludge, reducingenergy consumption by up to 70 percent compared to normal

systems and using heat which would otherwise be wasted.

This means that the digestate is not the only circular part of the

process. Heat generated by the engine used to generate electricity

is used initially in the pasteurisation process, and then regenerated

for use elsewhere on site, for example to heat water for cleaning.

Lawrence comments on his equipment decision making process:

“We were already aware of the quality and reputation of HRS Heat

Exchangers in the food production industry – using their solution

enables us to make use of an abundance of waste hot water. Not

only does the corrugated tube-in-tube technique deliver improved

performance, they’re also more resistant to fouling, which means

less downtime and maintenance. In addition, we had a shortdeadline – just 16 weeks – which HRS was able to meet easily.”

The AD plant is currently undergoing commissioning and will

become fully operational in late spring. For Muntons, the benets

are clear – better waste management, a reduction in tanker

movements, energy generation, and, thanks to its PAS 110 quality

pasteurised digestate. All in all Muntons has signicantly reduced

its carbon footprint saving 1159 tonnes of CO2 pa (from 27,264

to 26,605) – the emission equivalent of 300 average family cars

(approx.). 

With our Heat Recovery Dryer you get the

lowest energy consumption on the market.

TORNUM Grain Coolers – The eco-friendly

way of preserving grain quality.

Up to 30%Energy Savings

Heat Recovery Dryer

TORNUM AB Box 100, SE-535 22 Kvänum, SWEDEN

Phone +46 (0)512–291 00 E-mail: info@tornum.com

www.tornum.com

Milling and Grain - December 2015 | 67