Hydropath in Action - page 5

This is a very interesting application because it is one of the most difficult applications where a device like ours has been installed.
In a place where land is at a premium and where a lot of waste is generated, dumping sites like this are created and the waste is deposited in layers. These are then covered by tarpaulins and more layers are then laid on top, so that the same surface area can collect very large amounts of waste. To prevent the waste from degrading too quickly and creating a large amount of methane gas, a layer of lime is deposited on top of each layer. This slows the degrading of the waste to a more manageable speed. The gas is then collected and used to produce electricity. There is another bi-product which is released from this type of site and this is the water which has percolated onto the layers. It is called leachate. This water is concentrated with lime and ammonia and cannot be dumped directly into rivers or the sea. It has to be treated. The leachate is pumped into a treatment site, where it is heated and then the ammonia is evaporated and burned.

The process utilised is as follows. The leachate is pumped through a plate heat-exchanger and is initially heated by the returning hot leachate. The temperature is risen from 21 degrees to 27 degrees and then fed through the condenser.
This condenser is sitting on top of the ammonia tower and it condenses the steam that is coming out of the tower. At the same time this will heat the leachate from 27 degrees to 56 degrees.
The leachate is further heated, using a leachate heater, which uses steam from the steam generator.
This will rise the leachate to 63 degrees centigrade. Every time the

leachate is heated, scale is precipitating on all these heat exchangers. HydroFLOW units are installed on every stage, as the field is lost in each one of these heaters. The worst point is where the leachate is then injected at the top of the ammonia stripping tower. At this point, the leachate is sprayed on top of the plastic packing. This plastic packing is made from individual cylinders of plastic, which create a very large surface area. As the leachate flows over the surfaces, it is exposed to the steam, which is injected at the bottom of the tower. This will evaporate the ammonia from the water, releasing ammonia gas, which is then collected and burned in the ammonia burning tower. The effect of heating the water and exposing it to the rising steam releases all the Limescale that is dissolved in it.

This had, in the past, created a solid block of calcium carbonate, which required pickaxes to remove. With the use of a HydroFLOW unit at the top of the tower, after 80,000 cubic metres of leachate had been



treated, the tower was opened to observe the result.
As you can see the cylinders of plastic are still clear of scale. No scale deposits have formed on the surfaces and they are completely loose.

They remain individual plastic cylinders as they were when they were first put into the tower. The only difference is the colour, as they have been effected by the ammonia being released. This was a complete surprise to the operators, who were used to just seeing a mass of scale inside the tower, with the cylinders imbedded in scale. Prior to the HydroFLOW being fitted,The cylinder packing could not be used again and had to be renewed every time.

HydroFLOW installed before the plate heat exchangers at the beginning of the process.

The whole installation is of stainless steel as this is the only material that can withstand the corrosiveness and the pressures involved.

This is an extreme application of HydroFLOW, where huge heat exchangers are employed. The sugar juice suspended material is flocculated, using lime. This creates a large deposit of scale as the juice is being heated. The effect is so rapid that each of these heat exchangers can only last one six-hour shift, so the factory must have double the number of heat exchangers so that half can be cleaned while the other half is working.

There are large numbers of these heat exchangers. The covers at the top and bottom can be opened to facilitate cleaning. Each of these covers weigh half a ton and have to be lifted using chains and tackle.

The way to clean it, is to stand on top of it using long brushes, as long as 4 metres, to push the brush into each hole, about 400 holes, and slide it up and down to push the scale layer out of the bottom.
As you can imagine, it is very hard work and a very long time is spent doing this! Sometimes water jets are used for the purpose. These have to be slid up and down the hole.

The scale that is removed is between 1 and 1½ mm thick and it is enough to stop the heat transfer from the steam to the juice within a period of six hours.

HydroFLOW was used to maintain the heat exchanger to this level of cleanliness. Although they realised that the efficiency of the heat exchanger was still high, they had to open it to really believe this.

This is a very interesting installation, which is in China, in a welding gas manufacturing process. Waste product was generated, which was then pumped to a nearby cement factory, that was using this waste in the production of cement. The line was 2km long and only lasted about a year before having to be completely replaced and a new line laid.

The process of occlusion of the line forced the employment of three pumps, which were sequentially added on to increase the pressure, as the resistance of the flow increased.
When HydroFLOW was installed, the maintenance department wanted a simple and easy way to see the effect of HydroFLOW. Having no sophisticated equipment to inspect the line, they drilled a hole in the line so that they could introduce a rod so that they could measure the thickness of the scale, which turned out to be about 3cm thick.

After a few weeks of operation, and regularly in between, they would open the screw that was blocking the hole and fit a rod in to check the progress of de-scaling.

By measuring the distance that the rod had penetrated, they were able to witness the effect of de-scaling. At the same time, they were able to switch off the pumps until they had only one working. The welcome I received when I went to visit this company was fantastic and they insisted on having a meal in my honour.

This is a photograph of the pipe after the bolt and the screw have been put in and the hole sealed. This is what can be achieved without sophisticated instrumentation!