Mixing and Dosing Process
1. Plant Set-Up
Set-Up Overview for Each Plant:
· One Mixing Tank
– Preferably of 2 kL capacity
– Make SINTEX or equivalent
· One Agitator
– To be installed on the Mixing Tank
· Storage Tanks (# based on the plant’s total monthly requirement)
– Each tank to be of preferably of 10 kL capacity
– Make SINTEX or equivalent
· Transfer Pumps
– To deliver prepared UNISOL-28D (or E) solution from Mixing Tank to Storage Tank and from Storage Tank to Dosing Tanks
· Dosing Tanks
– 3-5 kL capacity
– Make SINTEX of equivalent
– To be kept at the about the same elevation as the dosing point
– Each mill to have one dedicated Dosing Tank
· Dosing pumps
– Preferably of Prominent Make
– Each mill to have one dedicated Dosing Pump
· Pipelines, starter boxes, mechanical and electrical accessories, etc
– Depending on the plant layout and requirement
Figure 1: Illustrative Flow Sheet of the Mixing and Dosing Assembly
2. Pre-Mixing Preparation
2.1. Inventory Assessment
2.1.1. Check existing tank levels
2.1.2. Estimate existing solution inventory by using following calculations
2.1.2.1. Assume tank’s storage capacity = Y
2.1.2.2. Existing solution level = h meters
2.1.2.3. Total tank height = H meters
2.1.2.4. Existing volume of solution in storage tank = Y*(h/H)
2.1.2.5. Repeat above estimation for each storage tank
2.1.2.6. Add total volume of each storage tank to arrive at total solution inventory (say l liters)
2.1.2.7. Say, total storage capacity = L liters
2.1.2.8. Volume of solution to be prepared = (L – l) liters = V liters (say)
2.1.2.9. Solution concentration to be prepared:
· UNISOL-28D
· 20% of Component A
· 10% of Component B
· 70% of Water
· UNISOL-E
· 25% of Component A
· 75% of Water
2.1.2.10. Specific gravity (say SG)
· SG of UNISOL-28D: 1.051 gm/mL
· SG of UNISOL-E: 1.06 gm/mL
2.1.2.11. Total weight of solution to be prepared = V * SG
2.2. Requirement Assessment for UNISOL-28D
2.2.1.1. Total storage capacity = L liters (say)
2.2.1.2. Volume of solution to be prepared = (L – l) liters = V liters (say)
2.2.1.3. Solution concentration to be prepared
· 20% of Component A
· 10% of Component B
· 70% of Water
2.2.1.4. SG = 1.051 gm/mL
2.2.1.5. Total weight of solution to be prepared = V * SG kg = W kg (say)
· Quantity of Component A required = W * 20% = w1 kg (say)
· Quantity of Component B required = W * 10% = w2 kg (say)
· Quantity of Water required = W * 70% = w3 kg (say)
2.2.1.6. Units of Components Required:
· Total # of Component A bags required = w1/25 = N1 (say)
· Total # of Component B drums required = w2/wB (where wB = weight of Component B per drum) = N2 (say)
2.2.1.7. Total capacity of Mixing Tank = M liters (say)
2.2.1.8. Total (suggested) water level per batch = 60% of M liters
2.2.1.9. Total number of bags of Component A per batch = M*60%*(20%/70%)/25 = n1 (say)
2.2.1.10. Total number of drums of Component B per batch = M*60%*(10%/70%)/wB = n2 (say)
2.2.1.11. Total number of batches to be prepared in 1 day = 6
2.2.1.12. Total number of bags of Component A required per day (8 hours) = 6 * n1 = na (say)
2.2.1.13. Total number of drums of Component B required per day (8 hours) = 6 * n2 = nb (say)
2.2.1.14. Therefore:
· N1 is the total number of bags of Component A required for the whole mixing process
· na is the total number of bags of Component A required for the mixing process per day
· N2 is the total number of drums of Component B required for the whole mixing process
· nb is the total number of drums of Component B required for the mixing process per day
2.3. Requirement Assessment for UNISOL-E
2.3.1.1. Total storage capacity = L liters (say)
2.3.1.2. Volume of solution to be prepared = (L – l) liters = V liters (say)
2.3.1.3. Solution concentration to be prepared
· 25% of Component A
· 75% of Water
2.3.1.4. SG = 1.051 gm/mL
2.3.1.5. Total weight of solution to be prepared = V * SG kg = W kg (say)
· Quantity of Component A required = W * 25% = w1 kg (say)
· Quantity of Water required = W * 75% = w3 kg (say)
2.3.1.6. Units of Components Required:
· Total # of Component A bags required = w1/25 = N1 (say)
2.3.1.7. Total capacity of Mixing Tank = M liters (say)
2.3.1.8. Total (suggested) water level per batch = 60% of M liters
2.3.1.9. Total number of bags of Component A per batch = M*60%*(25%/75%)/25 = n1 (say)
2.3.1.10. Total number of batches to be prepared in 1 day = 6
2.3.1.11. Total number of bags of Component A required per day (8 hours) = 6 * n1 = na (say)
2.3.1.12. Therefore:
· N1 is the total number of bags of Component A required for the whole mixing process
· na is the total number of bags of Component A required for the mixing process per day
2.4. Issuance of Goods from Stores
2.4.1. Request concerned plant official for issuance and transfer of Component A bags and Component B drums to the mixing tank location
2.4.2. Number of bags and drums to be issued should be either N1 or na and N2 or nb, respectively, depending on the plant’s specific housekeeping and space constraints
2.5. House-Keeping Checks
2.5.1. Keep a tarpaulin sheet underneath the place where Components A and B will be kept.
2.5.2. Ensure there are no leakages in the pipelines or valves or pumps
2.5.3. Keep a separate bin for throwing the empty bags
2.6. Safety Checks
2.6.1. All labor, technicians and personnel involved in the mixing process should wear:
2.6.1.1. Elbow-length rubber gloves
2.6.1.2. Helmets, Safety Shoes and Safety Glasses
3. Mixing Process
3.1. Marking Water Level
3.1.1. Water level should be marked, typically, to 60% of total height of the mixing tank.
3.2. Filling Up Water
3.2.1. Before filling up water, check and confirm that the outgoing line valve is closed.
3.2.2. Water pump / line should be switched on and kept on till the tank is filled up to the desired water level marking made in step 2.1.1
3.3. Emptying Bags
3.3.1. Total quantity of Component A to be used in the batch should be confirmed as per the following calculation
3.3.1.1. Total capacity of mixing tank = M liters (say)
3.3.1.2. Total height of mixing tank = K meters (say)
3.3.1.3. Water level = k meters (say)
3.3.1.4. Water quantity in the mixing tank = M * (k/K) liters = m liters (say)
3.3.1.5. Number of bags of Component A to be emptied in the tank:
· (m * 20/70)/25 for UNISOL-28D
· (m * 25/75)/25 for UNISOL-E
3.3.2. Number of bags emptied after each batch should be entered in the Table A provided in Documentation Section.
3.4. Agitation
3.4.1. Agitator should be switched on only after water, Component A (and Component B have all been emptied into the mixing tank
3.4.2. Duration of agitation should be determined depending on the ambient temperature:
3.4.2.1. For temperature > 30 degcel, duration should be 30-45 minutes
3.4.2.2. For temperature between 15 and 30 degcel, duration should be 45-60 minutes
3.4.2.3. For temperature between 1 and 15 degcel, duration should be 60-90 minutes
4. Storage
4.1. Solution prepared in the above process, should be transferred to storage tanks
4.2. Check and assess the storage tank levels before initiating transfer to avoid any possible overflows.
5. Dosage Drop Tests
5.1. Drop tests should be conducted once every shift to ensure accurate dosage of UNISOL-28D (or E) solution into the cement mill feed
5.2. Table B in the following section should be used to cross-check dosages.
6. Documentation
6.1. Use Table A below to keep a check on number of bags being consumed
Table A (Sample; for customized Excel Spreadsheet, contact UNISOL representative)
6.2. Use Table B below to ensure correct dosage
Table B (Sample; for customized Excel Spreadsheet, contact UNISOL representative)
7. Equipment Handling and Maintenance
7.1. Agitator
7.1.1. Never run the agitator without adequate water quantity
7.1.2. Never run the agitator in air
7.1.3. Never run the agitator submerged in solid powder portion
7.2. Motor
7.2.1. Lubricate regularly according to manufacturer’s instructions.
7.2.2. On sleeve-bearing and other oil-lubricated machines, check oil reservoirs on a regular basis.
7.2.3. In poor environments, change oil at least once a month.
7.2.4. Never over-lubricate; excess grease or oil can get into windings and deteriorate insulation. Be sure to use only the lubricant specified for the machine in question. However, one should also check into the possibility of using modern lubricants that have excellent life and lubricating qualities.
7.2.5. Bearing failures are one of the most common causes of motor failures. Typical bearing problems include improper lubrication, misalignment of the motor with the load, replacement with the wrong type bearing, excessive loading, and harsh environments.
7.3. Dosing Pumps
7.3.1. If the pump does not operate when turned ON:
7.3.1.1. Check the power supply and connections.
7.3.1.2. Check wiring color scheme.
7.3.2. If the pump operates but does not prime:
7.3.2.1. Check for a clogged or loose filter on the suction valve assembly. Retighten if necessary.
7.3.2.2. Check to see if the pump is too high above the foot valve assembly in the feed tank.
7.3.2.3. Check the pumphead, suction and discharge valves for blockage.
7.3.3. If pump flow rate is reduced:
7.3.3.1. Check the pumphead, discharge and injection valve assembly for any clogging. Clean and reassemble.
7.3.3.2. Check for any additional back pressure created since the last flow rate.
7.3.3.3. Check for any changes in the viscosity of the chemicals being used. Increase the % flow by adjusting the Flow Rate control to a higher setting and run a Flow Rate test.
7.3.3.4. Be sure that valves have been properly installed in the pumphead.
7.3.4. If there is leakage at the connections:
7.3.4.1. Be sure that the hose is fully seated and hose connectors are tight.
7.3.4.2. Be sure that valves are tight and O-rings are in place.
7.3.5. If there is leakage around the pumphead:
7.3.5.1. Be sure that the valves are tight and Orings are in place and the head screws are tight.