Waste Oil Heating Equipment Waste Oil Heaters are a special product which we have developed in conjunction with M&Q Associates to provide a robust and easily maintained heater. We have carefully examined the function of these heaters and how they behave in real working situations. We have made numerous improvements to the standard HFO designs you may be offered by others, which may not be suitable for use with Waste / Recycled Oil. From a practical aspect we ensure that the equipment is robust and will withstand many years of service in difficult environmental conditions. We respect the fact that engineers will inevitably have to work on the equipment at some point, therefore we ensure that maintenance and access to the electrical equipment is simple and that any maintenance can be undertaken with a minimum of effort. If something does go wrong - it can happen - we have a prompt spares and replacement service which can usually deliver within days. We appreciate you have a business to run as economically as possible, and know that downtime costs money. --Examples of Carbonised Heater Element Sheaths--   For all Waste Oil / Recycled Oil installations, you need look no further than an A.K. Waugh heater for peace of mind and low maintenance costs.

WASTE OIL HEATING Important Notes Due to the many installations now using waste or recycled oils as an alternative fuel in place of Heavy Fuel oils we feel that it is important to include some operational information which might be of use to site engineers. It is vitally important that waste / recycled oil should be of certified type that is, on no account should fuel be used which does not have documented properties. UPDATE - OCTOBER 2009 An article was published in Quarry Management dated October 2009 relating to the equipment specification for waste oil heaters. Please note that this article and the comments contained therein are designed to persuade you that there are particular safety requirements for waste oil heaters. This is not the case. Current British Standards for Oil Burning Installations remain applicable. The information provided with regard to ATEX requirements is incorrect and there is NO requirement for ATEX or "Flameproof" designation for our equipment when used with any Gas Oil, MFO, HFO or RFO (Waste Oil) A.K. Waugh Ltd. has always been at the forefront of anticipating design changes in advance of revised British Standards. We specified the use of safety cut-out thermostats a decade before the relevant BS was published. We remain dedicated to equipment safety and customer satisfaction in this regard and have an enviable product safety record. General Information a) Waste / Recycled Oil does not behave in the same way as HFO b) For Heaters, the correct heat output per unit surface area is of critical importance - in general, the lower the better. c) The design of the heater internals is of critical importance. d) A Waste / Recycled Oil system MUST BE PROPERLY MAINTAINED On the understanding that we are dealing solely with Electric In-Line Heaters with removable core type elements, we can take these points in turn for discussion, as below: a) Behaviour of Waste / Recycled Oil Waste oil is composed of a blend of many other oils. As such it may vary in viscosity from time to time, though this is not normally a problem which affects the heater. Oil circuit design is of primary importance due to the mixture of oils present. If the oil circuit design is poor the oil may undergo "cracking", producing a viscous sludge at the bottom of the heater casing. The heater in this case acts as a large filter unit. Over time, depending upon oil throughput and cleaning strategy, the sludge may eventually build up and foul the heating elements. In this event, if the lower heating elements are covered in sludge then the element sheaths will carbonize rapidly. Element overheating and failure will result. This is one failure mode. A secondary failure mode depends again upon design, this time with regard to heat retention within the oil circuit. Taking for example a typical 72kW heater - when this is on, this is the quantity of energy being transferred from the heating elements to the oil in a continuous process. If the oil then suddenly stops flowing while the energy is still being applied then the oil will locally absorb far more energy than normal and in the process it will tend to crack on the element/oil interface, leading to carbon build up. AKW heaters are designed to minimise this particular problem. Failure can be recognised when performance drops to a point where it is noticeable and the operator attempts to improve the situation by adjusting the thermostat to compensate for the lack of oil outlet temperature. This is a sign that the heater is struggling to release energy into the oil. The thermostat eventually runs out of range. The operator checks and finds inoperative elements, tries to withdraw them and finds them impossible to withdraw. The heater has actually failed in such a way as to require a new / replacement Tube Plate Assembly. Back to top   b) Importance of correct heat input to oil Through our work with HFO and constant contact with users / specifiers we have settled on a heat output per unit area which works for waste oil. This value is different from that for other oils. Carbon production is reduced to a minimum by our design. c) Design Due to the physical similarities of In-Line Oil heaters generally, one might assume that a heater suitable for HFO (usually Class G) would have the correct operating characteristics for Waste Oil. This is not necessarily the case, as HFO heaters are designed to work with a reasonably homogenous oil of fairly well known characteristics. There are major differences between HFO and Waste Oil, such that it is not recommended to use an HFO unit for Waste Oil heating duties. Our current design for Waste Oil heaters incorporates many features of our successful HFO heater range, being built to a similarly high standard. Additionally, considerable attention was paid to other aspects of design to optimise for Waste Oil. Back to top d) Maintenance It cannot be emphasised enough how important regular maintenance is with a waste oil system. Anyone who has seen the results of irregular or non-maintenance will confirm this. Inattention to this relatively simple task is expensive. Depending upon the volume of oil used over a period of time, a schedule of maintenance can be decided upon - although it is important to note that there is no set requirement. In addition to the task of cleaning filters etc., the heater itself should be inspected visually for signs of overheating within the terminal chamber. If there are such signs apparent then it is probably already too late to recover the situation. 1) Ideally, starting at the time of first use, a bi-weekly warm drain down should be carried out to remove any build up of sludge. After carrying out this task a few times the rate of build up should become obvious and the scheduling of the task may be adjusted to suit. Certainly a time period of no more than one month should be allowed from first use. If the above - given as an example only - is faithfully carried out, there should be no need to proceed to the next stage of maintenance for a considerable period. 2) Should the heater show signs of stress or should any of the conditions previously noted exist then the heater should be taken off-line immediately. If the heater fails to produce the required outlet temperature (after having successfully done so for a period of time) then this is a sure sign that all is not well within. Do not be tempted to assume that the thermostats are faulty - this is a very rare occurrence. The first indication of a problem would be evident upon removal of a heating element. If this simple action is not possible then the element sheath has relaxed, trapping the element inside. Assuming it is possible, upon removal of the Tube Plate assembly, (described elsewhere) one should expect to see large amounts of solid material covering the heating elements - hence the inability to reach temperature. The most usual remedy here is simply to remove elements if possible, for re-use, and then to cut off all tubes, returning the plate to us for re-tubing. In some cases it will be found that the build up of solids is sufficient to make it impossible to remove the tube plate, in which instance the whole unit should be immediately shipped to us, without delay, for refurbishment. Back to top This Page Updated 09.10.09