Category Archives: Copywriting

The Role of Zero Liquid Discharge in Reducing Hazardous Wastes

Thanks to tighter environmental regulations and greater public awareness, companies are increasingly looking to reduce or eliminate the waste that they produce. In recent years, Zero Liquid Discharge (ZLD) has become an important waste reduction technique, but its potential in dealing with hazardous waste streams has not been fully appreciated until now.

One of the advantages of ZLD over other treatment techniques is its theoretical ability to separate unwanted materials from water, whether they are benign, hazardous or toxic. The resulting solid residue is often more stable, making it suitable for recycling or landfill. A well-designed ZLD system should minimise or even eliminate liquid waste streams, resulting in clean water for reuse or environmentally-friendly discharge, and a solid residue suitable for further processing (often to recover valuable components for use elsewhere) or for safe disposal.

Correct analysis is crucial

The composition of wastewater streams varies greatly; certain wastewater sources, such as power plants and boilers with wet gas scrubbing, often contain salts which may be hazardous, valuable, or both. Environmental regulation usually means that treatment is required to reduce or remove such toxic compounds before wastewater can be discharged. Other sources, such as wet flue gas desulfurization, may contain highly soluble calcium and aluminium salts, as well as heavy metals, which are not easily crystallised by evaporation.

The effective design of any ZLD system, and the appropriate pre-treatment processes, is therefore dependent on the correct analysis of the water/waste stream, making it essential to have an accurate analysis of composition, flow rates, chemistry, etc. Without this, any designed solution will fail to deliver the required results, if it works at all.

Energy-efficient evaporation

Vapour compression evaporation is commonly used in ZLD as evaporation can recover up to 95 per cent wastewater as distillate. Any remaining concentrate is further treated physically or chemically to produce solid residues (such as crystals) and water. By running the evaporators at lower pressures, the boiling point of the liquid being treated is reduced. This means that multi-effect evaporation can be made possible; that is, steam from a previous evaporation stage is used as thermal energy in the next stage which works at a lower boiling point. This way, multiple evaporation stages are combined, generating significant energy savings. For many components, crystal precipitation is favoured at lower temperatures, therefore lowering evaporation temperatures helps to increase the solids yield.

The role of heat exchangers

HRS Heat Exchangers is in the final commissioning stage of a ZLD system for an industrial client in Europe. Heat exchangers play a crucial role in reducing the running costs of a ZLD system by utilising heat from process water and other existing sources, and also recapturing heat at the end of the process and reusing it to boost the energy efficiency of the overall ZLD system. Where there is a hazardous liquid waste stream to deal with, then the potential to utilise ZLD techniques as part of the overall treatment solution should definitely be investigated, and HRS staff would be happy to discuss the potential options with you.

1 http://nimkartek.com/blog/zero-liquid-discharge-a-solution-to-zero-discharge-of-hazardous-chemicals/

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Heat Exchangers to improve AD plant efficiency

At BioCycle REFOR18 stand 38, HRS Heat Exchangers will be demonstrating the crucial role that heat exchangers can play in improving the overall efficiency of biogas plants: from pre-heating feedstock to concentrating and pasteurising digestate.

HRS Heat Exchangers provides a wide range of dedicated heat exchangers for the anaerobic digestion sector around the world, including feedstock and sludge heaters, multi-tank pasteuriser systems, evaporators, exhaust gas cooling, thermal hydrolysis, the HRS Digestate Concentration Systems (DCS) and the HRS Biogas Dehumidification System (BDS). Due to their high efficiency design which can include heat regeneration, not only do many HRS units need no additional energy input – instead utilising existing previously wasted heat from CHPs and other processes, but they maximise the amount of heat which can be re-used again.

HRS Heat Exchangers’ International Sales & Marketing Director Matt Hale explains:
“Every anaerobic digestion (AD) facility is different, but all of our systems are designed to recapture and utilise energy which would otherwise go to waste. Not only does this increase the efficiency of both our equipment and the AD plant overall, but it is also good for your pocket and good for the environment.”

Experienced HRS staff will be on hand throughout the BioCycle REFOR18 event to explain the full range of HRS products to the anaerobic digestion sector, including:

  • Biogas cooling: cooling and recapturing the heat from exhaust gases, for example using an HRS G Series heat exchanger, can increase the efficiency of combined heat and power (CHP) plants, with the recovered energy being used elsewhere in the plant.
  • Feedstock and sludge heating: maintaining the ideal digester temperature (particularly in the case of thermophilic plants) is essential for full material conversion, while pre-heating the feedstock prior to putting it in the digester can reduce the amount of heat needed in the digester itself. For such applications the HRS DTI Series of heat exchangers is ideal for ensuring a high level of heat transfer while minimising blockages or fouling.
  • Feedstock or digestate pasteurisation: not only are there legislative or quality drivers for pasteurisation, but operators of AD plants are increasingly seeing pasteurisation as a way of demonstrating the quality of their digestate product and increasing its value. HRS DPS (Digestate Pasteurisation Systems) are specifically designed to cope with difficult materials while maximising energy efficiency.
  • Digestate concentration & evaporation: reducing the volume of digestate can not only improve its quality as an organic fertiliser, but it also reduces storage, transport, application and disposal costs. The HRS DCS (Digestate Concentration System) uses a multi-stage evaporation process to concentrate digestate.
    Thermal hydrolysis for enhance biogas production: HRS has developed a process for the continuous thermal hydrolysis of digester sludge. This treatment changes the cell structure of the compounds, breaking down lignin and hemi-cellulose chains to create free sugars which are easier for the bacteria to digest.
  • Biogas Dehumidification System: The HRS BDS Series is an efficient solution to cool and dehumidify biogas for combustion. The system condenses up to 90% of the water contained in the gas, which is continuously separated before the lean biogas is ready for use.

Matt Hale adds:
“If you have an AD plant, then we can supply the best system for any thermal process associated with the feedstock, digestion, biogas or digestate. Not only that, but a heat recovery step can be included as a standard option on most of our systems, reducing energy costs by between 20 and 40% which also reduces the payback period considerably. Most of our equipment is easily integrated into existing plants, or we can design bespoke solutions for more complex applications. In addition our systems include state of the art system monitoring and cleaning systems, to reduce management time and effort.”

Learn more about the full range of AD systems from HRS Heat Exchangers on Stand 38 at BioCycle REFOR18 in October.

The post Heat Exchangers to improve AD plant efficiency appeared first on HRS Heat Exchangers.

Think you can’t evaporate with low temperatures? Think again…

When treating wastewater, sludge and digestate, it can be beneficial to reduce the volume of material or increase the solids content. Mechanical dewatering via a centrifuge or belt press to separate solids and liquids is standard for the water treatment and anaerobic digestion sectors – but what if you want to further reduce the water content of the remaining liquid fraction?

The two main reasons to remove or reduce water from effluent and waste are either to reduce the volume of material in order to cut storage, handling and disposal costs; or to produce materials with distinct properties (such as liquid and solid fractions of digestate), which can then be stored and used in the most appropriate way. The traditional options are drying (which requires large quantities of heat and energy, is costly and inefficient) and evaporation (usually requiring temperatures in excess of 100ºC).

Energy efficient evaporation

However, for many types of effluent, low temperature evaporation can be very energy efficient. Where process temperatures are 85-90º C, low temperature evaporation combines the use of a vacuum to reduce the boiling point of the liquid to be removed, together with traditional high temperature evaporators, based on heat exchanger technology, and surplus heat from heaters and CHP engines can often be utilised for the process.

Heat exchangers from HRS are capable of recovering such heat and using it as the basis for an evaporation system can further improve overall process efficiency. Additionally, using a vacuum in the system to reduce the boiling point reduces the amount of energy required even further. Combining systems into a multiple-effect evaporator allows larger quantities of water to be removed for the same initial heat input, with the vapour boiled off in one vessel used to heat the next.

Selecting the right heat exchanger

The type of heat exchanger used will depend on the nature of the products being treated. For materials with low or medium viscosities, such as wastewater and effluent with low concentrations of organic solids, using the HRS K Series as an evaporator module provides high heat transfer rates with good resistance to fouling. For more challenging and viscous materials, such as thicker effluents, digestate and solids with higher dry matter concentrations, the HRS Unicus Series contains a self-cleaning scraper mechanism which reduces fouling and maintains heat transfer rates (and therefore operational efficiency).

While both the K Series and Unicus Series are commonly used in the type of multi-effect evaporation system described above, both heat exchanger models can also be used in other types of evaporator, such as mechanical vapour recompression (MVR) or thermal vapour recompression (TVR) systems, depending on the needs of the product or application.

The ultimate use of HRS heat exchangers for low temperature evaporation can be found in the HRS Digestate Concentration System (DCS), which uses multiple evaporation effects to increase the solids in liquid digestate three- to four-fold. Whether you want to minimise effluent and digestate volumes using the DCS, or simply reduce them in a more energy efficient way, HRS Heat Exchangers has a low temperature evaporation solution to achieve the required results.

The post Think you can’t evaporate with low temperatures? Think again… appeared first on HRS Heat Exchangers on 10 July 2018.

Heavy duty heat exchanger tackles nut butter challenge

Nut butter is one of the big food trends of the last two years. Once the only choice on the shelf would have been between smooth or crunchy peanut butter, but recently, as the health benefits of quality nut butter have been understood, the market has exploded to include peanut, almond, cashew, and even seed butters, often including other additives such as high quality cocoa, coconut and coffee. However, producers of these products all share one major challenge. Nut butter is extremely viscous – almost solid at low temperatures – making it very difficult to move through processing machinery.

Most nut butters are semi-solids, as shown by the fact that they will hold a peak. At room temperature peanut butter is at least five times thicker than tomato ketchup, but at colder conditions it becomes even more viscous, as anyone who has tried to spread it straight from the fridge will know. Adding stabilisers, such as partially hydrogenated vegetable oils, to prevent oil separation, can actually make the problem worse as they form a crystalline structure with higher levels of viscosity.

For HRS Heat Exchangers the problem was highlighted when a client ordered an R Series Scraped Surface heat exchanger for a nut butter line, as HRS International Sales and Marketing Director Matt Hale explains:

Although the R Series is purposely designed for viscous materials some very solid materials, like low temperature peanut butter, were a step too far. The thickness of the cold nut butter was beyond the parameters of the R Series gearbox and its mountings, and the unit we were testing failed. However, the experience highlighted the need for a heavy duty version of the R Series, so our R&D team set to work to produce a scraped surface heat exchanger for materials like nut butters that are almost solid. The result is the new HRS RHD Series for heavy duty applications.

The HRS engineering team set out to maintain the benefits of the standard R Series – such as the continuous scraping action to enhance the mixing of viscous products and the unique sealing system which allows for the removal of individual tubes for cleaning or maintenance – but increase its strength and durability.

As well as expanding the motor size from 4 kW to 7.5 kW, and bolstering the gearbox size accordingly, the overall heat exchanger was also reinforced. The scraping rod was made bigger and stronger, with heavy duty bearings and lips seals to accommodate increased torque. Further along the tube, an extra support for the scrapers was added to cope with the weight and increased forces. Finally, an extra external support was added to the motor end of each RHD unit to cope with the extra weight.

Matt continues: “The standard R Series of rotating scraped surface heat exchangers from HRS Heat Exchangers have been proven time and time again in both food and hygienic applications for their ability to reliably process viscous products such as sauces, purées, creams and gels. With the addition of the new HRS RHD Series, we can now deliver these benefits to the thickest and most difficult to handle materials, such as nut butters or any semi-solid product.”

The post Heavy duty heat exchanger tackles nut butter challenge appeared first on HRS Heat Exchangers on 7 August 2018.

Unique R Series scraped surface heat exchanger solves viscous product challenges

Different materials need different types of heat exchanger. For the simplest fluids such as water and milk, plate heat exchangers are often sufficient, but as products become more challenging (for example more viscous, or containing particles), then different types of tubular and scraped surface heat exchangers are required. For those products with extremely high fouling potential, or those which benefit from constant agitation (for example to keep solid particles in suspension), then the HRS R Series of rotating scraped surface heat exchangers is ideal.

Designed for both sanitary and industrial applications, the R Series from HRS Heat Exchangers uses a rotary scraper rod which is capable of reaching velocities of 300 rpm, providing high levels of shear and mixing at the heat transfer surface which dramatically increases heat transfer rates. This makes it particularly suitable for challenging heat transfer applications, such as those where the product has the potential to crystallise during processing or where aeration is required.

The scraper rod features both a helical mixing spiral (which reduces the pressure drop in the tube) and a series of scraper blades. Together these provide a continuous scraping action which mixes highly viscous products and reduces fouling. The unique design enables high viscosity products to be pumped with reduced back pressure and lower energy use, in a compact unit which features a much smaller footprint than traditional heat exchangers for similar applications.

A unique gearbox design not only reduces noise, but also allows multiple tubes to be fitted inside a single shell from a single electrical drive, further increasing the available heat transfer area within the same shell footprint and aiding maintenance. Cleaning and maintenance is further improved by the unique sealing system used in the R Series which allows individual tubes to be removed for easy servicing and replacement if necessary.

Thanks to its helical spiral, in many applications the R Series can also be run in reverse, enabling much valuable product to be recovered before routine cleaning or product change-over without the need for additional pigging or flushing systems. Not only does this reduce costs and complexity, but saving product adds dollars to the bottom line.

HRS International Sales & Marketing Director Matt Hale comments: “Normally, when processing viscous or sticky products such as honey, syrups and purées, a certain amount will adhere to surfaces. This greatly reduces heat transfer, meaning that longer exposure is required to compensate. With its clever scraper design the R Series overcomes this problem, and also reduces product  losses which can soon add up. For example, product lost during processing is estimated to account for 3% of total losses in the US dairy industry. The R Series can be emptied of the majority of the product without the need for any additional pumps or pressure systems, reducing both capital- and running-costs.

The HRS R Series is available in two lengths (1 and 2 meters) and with one-, three- or six-tube options providing a range of surface areas between 0.35 and 4.2 m2. For larger installations multiple units can be combined in series and units can be mounted horizontally or vertically and internal baffles can be specified within the tubes to overcome situations where shell-side flow may be limited. This also means that it is possible to obtain complete counter-current flow between the shell-side and tube-side fluids for multi-pass designs. In other situations, such as condensing (e.g. stem heating) and evaporating (e.g. ammonia cooling) the baffles are not used, in order to improve performance.

The R Series is suitable for a range of uses in the food processing and cosmetic industries, including heating, cooling, pasteurisation, crystallisation and evaporation.

For some materials, such as curd production in the dairy sector and many concentrated products and creams, increased turbulence is beneficial,” adds Matt. “With its small footprint, ease of maintenance and the ability to recover product, in these situations the unique design of the HRS R Series offers a number of advantages over other heat exchangers on the market.

The post Unique R Series scraped surface heat exchanger solves viscous product challenges appeared first on HRS Heat Exchangers on 19 June 2018.

Effectively recovering product from pasteurisers and sterilisers

A key challenge in the food industry is recovering valuable product which is left in equipment and pipework after production runs, for example between product change-overs and before cleaning. Product lost in this way increases operating costs unnecessarily and affects beverage manufactures to sauce producers, fruit and vegetable purées, and many other products.

Companies often use ‘pigging’ systems to remove such retained product, particularly in the last portions of their production process. Some of these systems are very simple, while others can be very complex. The pigging device physically recovers material from the system and is often an integral part of CIP (Cleaning in Place) cycles. Other alternatives are to use water or clean air to ‘push’ the product through the system until such time as the product is either too diluted or the product seal in the pipework is broken.

All three of these approaches will salvage some residual product, but a certain amount of usable product will inevitably be lost as waste. However, by using inline measurement and automatic control, you can guarantee that the maximum amount of product possible is recovered from pasteurisers and sterilisers in the production line.

Re-using an established concept

The concept of a feedback loop to continually measure and control a process is well established in automated food production. For example, every HRS pasteuriser or steriliser has a temperature transmitter and a three-way valve installed after the holding tube. If, for any reason, the set pasteurisation or sterilisation temperature is not maintained in the holding tube, the temperature transmitter sends a signal to the valve to return the product back to the holding tank.

This prevents any product that may not have been adequately pasteurised or sterilised entering the food chain and allows products to be recovered and reworked if appropriate. The same principle can be applied to universal product recovery, measuring different parameters.

Some practical examples

If we imaging a fruit juice production line, an inline Brix meter positioned after the pasteuriser can monitor the sugar concentration against a target level of 12 oBx (the set point). When the concentration falls below the set point, a controller diverts the remaining product away from the filler.

Such an approach overcomes any doubts about where the ‘mixing zone’ may begin when water is used to push product through the system as it can be accurately measured in situ. In addition to maximising product recovery, the waste being produced will be cleaner (as there is less product in it), potentially reducing disposal or treatment costs.

In the previous example we have used an inline Brix meter to measure sugar concentration, but it is possible to use a suitable device to measure any physical property (pH, viscosity, density) depending on the best criteria for the product.

For example, a US manufacturer of BBQ sauces makes a profit of $2 on every gallon of sauce produced. If the company loses 100 gallons of sauce per day, profits decrease by $200 per day. Based on 300 days of production a year, this equals $60,000 dollars a year. If this was repeated across four production lines the company could be losing almost a quarter million dollars ($240,000), not to mention the costs of treating and disposing of the wasted product. Even a 50% reduction on waste across all lines would save $120,000 a year, covering the costs for the installation of a system.

Using the system in practice

These examples have focused on the end-of-run condition for processing. However, this system also helps reduce product loss on start-up. For example, if a production line is ‘warmed up’ with water, the water is typically ‘pushed’ out by the product until a certain condition is reached. This system accurately establishes when that point occurs, eliminating the guesswork and automatically saving even more usable product each run.

This type of system can be installed with any existing system (pasteuriser, steriliser, hot filling) with very little downtime. Real world payback times will depend on the quality of the instrument used and the value of the product, but average payback periods are between 1 and 6 months. In addition to improving bottom line profits, there are also environmental benefits. Recovering more product saves on energy required to process waste streams, reducing waste and lowering the carbon footprint.

HRS Heat Exchangers have successfully installed several of these systems in plants around the world, helping clients choose the right instrumentation and the correct software for the system. If you have a project that involves product recovery or you are interested in learning more, please contact us.

The post Effectively recovering product from pasteurisers and sterilisers appeared first on HRS Heat Exchangers

Reduce digestate volumes with HRS

At UK AD & World Biogas Expo 2018 stand D603, HRS Heat Exchangers will showcase its novel Digestate Concentration System (DCS), which increases the dry solid content of digestate three-or four-fold, typically to between 10-20 per cent.

By reducing the liquid fraction and therefore the overall volume of digestate produced, the DCS minimises the economic and logistical challenges associated with digestate storage, transportation and application. Up to 60 per cent less storage capacity is needed and fewer tanker loads are required, helping to curb an AD plant’s transportation costs and carbon footprint. And with an average 1.5 MW AD plant generating 40,000 tonnes of liquid digestate each year, that can mean significant carbon and financial savings.

By reusing heat from existing sources, such as the CHP engine, the DCS is virtually energy self-sufficient. Water removed by the process is recovered and can be mixed with AD feedstock at the front-end of the plant, increasing the efficiency of the digester. The DCS also overcomes odour issues and increases the nutrient content of digestate via acid-dosing with sulphuric acid – while the volume of digestate is reduced, the nutrient content actually increases.

The HRS DCS is a plug-and-play, fully automated system which is completely flexible and can be tailored to meet the requirements of individual AD plants. The technology is installed at a number of facilities worldwide and is helping operators to reduce their storage, transport and application costs, as well as their water usage, while using spare heat which would otherwise be wasted.

International Sales & Marketing Director Matt Hale explains why increasing numbers of AD operators are specifying the Digestate Concentration System for their sites: “At a time when the efficiency of AD plants and bio-waste management is under scrutiny around the world, being able to maximise the financial and nutrient value of your digestate, while at the same time reducing storage, transport and application costs, is an exciting proposition. The HRS DCS represents the most efficient method of achieving these goals.”

Learn more about how the HRS Digestate Concentration System (DCS) can solve your digestate challenges and improve your overall plant efficiency on Stand D603 at the UK AD & World Biogas Expo, NEC Birmingham, in July.

The post Reduce digestate volumes with HRS appeared first on HRS Heat Exchangers on 6 June 2018.

Twin partnerships to address soil health

Soils are fundamental to almost all forms of crop production, so adopting a rotational approach to soil health makes sense. That’s why AHDB has funded a five-year programme of research and knowledge exchange into key aspects of soil health as part of the GREATsoils programme. With the first information gathering reports published, the work is now moving into the next phase – Experiments and on-farm trials designed to answer key questions raised by farmers and growers about how they can practically improve soil health in their own fields. Read more…

Unique heat exchanger increases resource efficiency by cutting process waste

With resource efficiency topping the agenda at this year’s Anuga FoodTec show, HRS Heat Exchangers is shining a light on a forgotten area of wastage in food processing – food lost during cleaning cycles and production changes. The HRS R Series of scraped surface heat exchangers removes food residue, meaning that food factories can now recover valuable product from the exchanger when heating, cooling or pasteurising viscous/sticky foods.

HRS International Sales & Marketing Director Matt Hale explains: “Normally, when processing viscous food products such as honey, syrups and purées, a certain amount will adhere to surfaces, such as the inside of pipe work, or become left in equipment after processing. The value of these lost products soon adds up. For example, this issue is estimated to account for 3% of product losses in the US dairy industry1.”

Globally some 5% of food loses occur during processing, although this varies according to region. In European countries the average figure is around 5% but this rises to 9% in North America2. To put this into context, that’s 4.1 million tonnes of food being lost during processing each year in the UK alone3. The sectors with the highest waste levels are dairy, animal and meat processing, fruit and vegetable processing and the manufacture of oils and fats4.

Traditionally flushing or so-called ‘pigging systems’ have been used to push product through key parts of the production system, like heat exchangers. However, both add complexity to the system and can result in high levels of product wastage. However, running a suitable scraped-surface heat exchanger, such as the HRS R Series, in reverse, enables the recovery of material without the need for such additional equipment.

The HRS R Series scraped surface heat exchanger is capable of removing much of the product before the cleaning or change-over cycle commences. This is made possible thanks to a scraper bar within each inner tube which enhances product flow; prevents fouling during operation and minimises the pressure drop. The scraper bar features a helical screw which rotates at high speed. When configured correctly, this screw can be run in reverse, removing product from the heat exchanger tubes without damaging it or changing its characteristics. The R-Series can be configured for both horizontal and vertical operation, so that gravity can also be used to help recover product from the tubes. Each unit can be supplied with one, three or six tubes and multiple units can be combined for larger installations.

“The R Series is particularly suitable for high value viscous products such as honey, treacle, custards and creams, where lost product can be expensive,” adds Matt. “The R Series can be emptied of the majority of the product without the need for any additional pumps or pressure systems, reducing both capital- and running-costs.”

Learn about the benefits of the HRS R Series on Stand D069 in Hall 10.2.

Originally posted at PandCT.com on 5 February 2018.

BEJO PRESENTS: THE NEW BEJO ROOT MAGAZINE

I don’t know what your Dutch is like, but there is a translation based on one of my reports in here:

A magazine full of inspiring interviews and useful information about cultivation, trade and trends in the range of carrots. The root is in the top 10 food crops worldwide and carotenoids have a positive impact on health. With the Bejo root magazine Bejo informs its growers and relations about the root market and growing areas in the Netherlands, Belgium, Germany, France, Italy, Poland, Japan and the US.