CHALLENGE: Improving production in conditions where equipment is in the ATEX zone
SOLUTION: Installation of AODD pumps
Alcohol or ethyl alcohol, ethanol, spirit is a popular name for the organic compound from the group of alcohols. Appears as a colorless liquid with a pleasant smell. Alcohol is produced mostly from starch and sugar raw materials by fermentation with yeast. It is used as a solvent and extracting agent, for disinfection, for preservation and for the production of alcoholic beverages. It serves as a raw material for a whole range of chemicals. Challenges for the equipment suppliers when selecting equipment are related to the ATEX zone in which most of the equipment is located, the physical and chemical characteristics of the product (light volatility and flammability, potential problems with mechanical seals) and problems with abrasion during the transport of the initial mixture (cereals + water and acid).
All the mentioned problems were noted on the project of relocation and modernization of the factory of ethyl alcohol (produced from corn). The factory had old equipment mainly based on mono pumps at the initial production stage to centrifugal pumps in the distillation sector. The idea of an engineer from the factory was to change the pumps with the same type (purchasing the centrifugal pumps again). Visiting the site Tapflo specialist realized that in most positions no large flows and pressures are required. As a result installation of diaphragm pumps powered by compressed air was offered - more elegant and technically more correct solution.
The client trusted Tapflo as a respectable pump manufacturer and agreed to equip production with AODD pumps. With this change of pump type, the client recorded multiple winnings, and some of the main advantages are:
- Absence of electric current for pump operation in the ATEX zone, therefore less possibility of explosion
- Pump tightness. Unlike centrifugal pumps, the diaphragm pumps do not possess rotational parts and therefore sealing of the pumps is simpler and lasts longer.
- Possibility of dry run. The factory itself is not at a high technological level and production much depends on the operator. Using diaphragm pumps, the operator has a certain safety time during which the pump can run dry without damage, which is not possible with centrifugal pumps.
- Adjustment of pump capacity is simple, on the site with needle valve, no expensive frequency regulators are needed
- Pump material/Price. Pumps for most applications are made of aluminum, which significantly influenced to reduction of the purchase price and investment itself will be returned faster.
- Position substitution. In agreement with the client, a selection of pump sizes has been made in a way which allows pumps to be easily replaced from another position in case of need (sudden breakdown, etc.) and the process continues smoothly
- Easy maintenance.
The pumps have been installed and put into operation in 2016, and since then they have been operating 24 hours a day since the factory works in 3 shifts, without stopping. After a month, the problems appeared in a single position that transported hot alcohol from the distillation column. Tapflo service team opened the pump and found out that there was unexpected wear of the suction and discharge manifold, and there was certain wear visible on the pump's working chambers/casing. These damages are connected to the alcohol temperature - influence of hot alcohol on the aluminum from which the pump casing was made. For this position, Tapflo changed the pump to a one made of AISI 316 stainless steel, and since then there was no problems with this position.
In the second phase of factory modernization, Tapflo engineers faced the challenge of transporting a mixture of mashed corn, water and sulfuric acid. The fluid itself was problematic in many ways, the corn pieces made it very abrasive, and on the other hand, the acid content was the reason for chemical aggression.
For this position progressive cavity pumps were installed long time ago, and during production operator often had to stop the pump due to stator damage, and beside that, the area around the pump was very messy because the pump seal was constantly leaking. As a solution, a hollow rotary disc pump was used for some time, but it turned out to be a poor solution because corn pieces entered beside impeller and disrupted the geometry of the pump parts causing intense wear and reduction in capacity. Looking for a solution of this problem, we presented to the costumer the benefits of an AODD pump, however, this has caused suspicion because the pulsating flow that the AODD pump produces can cause a misreading of the flow meter located on the discharge pipeline and thereby endanger the process. Our engineers responded to this suggestion with the offer of the TK series of AODD pumps, with integrated pulsation dampener.
The client liked this solution and ordered the recommended pumps. Using the collected process data and problems with existing pumps we made careful selection of materials (PE housing, membrane and valves made from EPDM). Thanks to the solution offered by Tapflo the customer managed to overcome both obstruction from the fluid, and using the pulsation damper, a constant flow and accurate reading on the flow meter. The pump was installed and put into operation in 2018 and preventively opened after 2 months of operation to control parts. It has been found that the pump parts are in factory tolerances and the pump was assembled and put into operation.