Author: Site Editor Publish Time: 09-20-2026 Origin: Site
Upgrading an existing milk powder production line involves more than simply replacing an evaporator, drying tower, or packaging machine. The correct approach is to first define the upgrade objectives, identify the bottlenecks limiting the entire line, and finally formulate a modification plan with quantifiable acceptance criteria.
Purchasing equipment without first conducting a comprehensive assessment of the entire line carries a high risk that the new equipment will fail to achieve its design capacity and may merely shift existing bottlenecks to other stages of the process.
Table of Contents
An upgrade project must have a clear, primary objective. Common objectives include:
• Increasing the hourly output of compliant milk powder
• Reducing steam, electricity, and water consumption per tonne of finished product
• Improving product specifications such as moisture content, solubility, and bulk density
• Increasing production capacity for instant milk powder or other new products
• Reducing downtime, cleaning time, and manual labor
• Addressing issues related to hygiene, dust, or equipment aging
Do not assign the same priority level to all objectives. Instead, establish a primary objective first and treat other requirements as constraints.
For example, if the project's primary objective is to increase output, the acceptance criteria should be based on the yield of compliant finished product during continuous production, rather than simply comparing the rated processing capacity of a specific piece of equipment.
Without accurate production data, it is impossible to determine where modifications are needed.
The assessment should be based on stable production records from recent months and must, at a minimum, verify the following data:
• Actual hourly feed rate
• Hourly output of qualified finished product
• Solids content of raw milk
• Solids content after evaporation/concentration
• Consumption of steam, electricity, and water per tonne of finished product
• Product yield and powder loss
• Effective runtime per continuous production cycle
• Cleaning frequency and duration
• Downtime and causes for each process stage
• Finished product moisture, solubility, bulk density, and microbiological test results
Data must be derived from normal operating conditions; relying solely on equipment nameplates, design specifications, or short-term trial run results is insufficient.
If the production line's actual capacity is significantly lower than its original design capacity, the performance of existing equipment should be restored first. Expansion should not be undertaken until issues such as fouling, nozzle wear, filter clogging, reduced heat exchange efficiency, or instrument inaccuracy have been resolved.
The maximum output of a production line is determined by its weakest link, not necessarily by the most expensive or largest piece of equipment.
When identifying the bottleneck, the entire line should be evaluated from raw material intake to finished product packaging:
• If evaporation capacity is insufficient, resulting in low solids content in the concentrate, the drying system is forced to evaporate more moisture; in this case, evaporation capacity should be increased first.
• If the evaporation system has spare capacity but the drying system has reached its limits regarding temperature, exhaust airflow, or moisture control, the drying system should be upgraded.
• If the drying system frequently shuts down because the finished product silo is full, the bottleneck lies in packaging and product conveying, not in the drying system.
• If production capacity gradually declines after startup, issues such as fouling, powder buildup, or cleaning cycles should typically be addressed first.
• If the equipment has the necessary processing capacity but the supply of steam, electricity, cooling water, or compressed air is inadequate, utility infrastructure should be expanded first.
Current issues | Potential bottlenecks | Possible upgrade paths |
Insufficient evaporation capacity | Evaporator | Increase evaporation capacity |
The evaporation system still has spare capacity, but the drying system has reached its control limits regarding temperature, exhaust airflow, or moisture content | Drying system | Upgrade the drying system |
Frequent shutdowns of the drying system due to the finished product silo being full | Packaging and finished product conveying system | Upgrade the packaging and finished-product conveying systems |
Production capacity gradually declines after startup | Cleaning system | Address issues related to scaling, powder buildup, or cleaning cycles |
The equipment has the processing capability, but the supply of steam, electricity, cooling water, or compressed air is insufficient | Auxiliary systems | Expand utility systems |
Unable to increase overall production capacity | Evaporation system, drying system, and packaging stage | First, identify the specific problem areas, then address them one by one. |
The correct principle for expanding production capacity is to upgrade the bottleneck (the process with the lowest capacity) while simultaneously verifying the preceding and succeeding processes. Simply increasing the capacity of a single piece of equipment does not guarantee an increase in the output of the entire line.
If the goal is to increase production output:
First, identify the current bottleneck, then conduct a synchronized assessment of the bottleneck equipment and the processes immediately upstream and downstream of it.
If the evaporation system is the bottleneck, increase concentration capacity while verifying that raw material supply, preheating, drying, and concentrate transfer capabilities are sufficient to match the new capacity.
If the drying system is the bottleneck, evaluate the capacities for air intake, exhaust, atomization, powder separation, fluidized cooling, and finished product conveying. Simply enlarging the drying chamber without upgrading the undersized auxiliary systems is not a viable solution.
If the packaging stage limits continuous production, prioritize increasing capacities for intermediate storage, conveying, and packaging; in this scenario, upgrading the drying equipment alone will not increase the final shipment volume.
First, install or calibrate sub-metering systems before determining the retrofit plan. Without sub-metering data for steam, electricity, and water, it is impossible to verify energy-saving results.
The typical order of priority for energy-saving retrofits is:
• Increasing solids content prior to the drying stage
• Optimizing thermal energy utilization in the evaporation system
• Recovering usable condensate and waste heat
• Minimizing hot air and powder leakage
• Optimizing multi-stage drying and cooling processes
• Reducing unproductive operation and cleaning times
If a significant amount of moisture that should have been removed during evaporation is instead carried over into the drying stage, optimizing drying parameters in isolation will not yield ideal energy-saving results.
To improve product quality, one must first identify the specific parameters requiring improvement before selecting the direction for equipment and process modifications.
In cases of significant moisture fluctuation, the feed concentration, flow rate, atomization, and temperature control should be inspected. If solubility is inadequate, the focus should be on evaluating particle formation, agglomeration, and subsequent fluidization treatment. For unstable bulk density, the atomization method, droplet size, and drying conditions should be checked.
Producing instant-dissolving products typically requires enhancing capabilities in agglomeration, fluidization, additive incorporation, and cooling; simply adjusting the existing drying temperature is insufficient to consistently achieve instant-dissolving properties.
Mechanical, instrumentation, and cleaning issues should be resolved before upgrading the control system.
While control systems can improve recipe management, process repeatability, alarm analysis, and operational consistency, they cannot compensate for valve leakage, heat exchanger fouling, nozzle wear, or insufficient equipment capacity.
The correct sequence is to first restore the equipment to proper operating condition, and then implement instrumentation, automatic controls, and condition monitoring.
Any upgrade plan must verify the following conditions:
• Adequacy of existing steam, electricity, cooling water, and compressed air supplies
• Compliance with requirements regarding facility height, floor load-bearing capacity, and maintenance clearance
• Feasibility of hygienic connections between new and existing piping, valves, and equipment interfaces
• Necessity of simultaneous upgrades to exhaust ventilation, dust collection, and explosion-proof measures
• Coverage of the cleaning system for the new equipment and piping
• Compatibility with upstream feeding and downstream packaging capacities
• Ability to integrate the new equipment into the existing control system
• Potential impact of the retrofit work on adjacent production areas
If even one of these critical conditions is not met, the equipment quote does not constitute a complete project budget.
Upgrading the existing production line is a reasonable choice when:
• The structure of major equipment remains reliable
• Issues are concentrated in one or two specific stages
• The facility and utilities allow for expansion
• Hygiene and safety issues can be fully resolved through modification
• Post-modification capacity meets future production plans
• Construction can be completed within an acceptable downtime period
Fragmented modifications should not be pursued when:
• Multiple core systems are simultaneously nearing the end of their service life
• Existing equipment fails to meet basic hygiene or dust safety requirements
• Facility space and utilities lack expansion capability
• Control systems are obsolete, preventing stable integration of new equipment
• Target output or product standards remain unattainable after modification
• The cumulative cost of multiple partial modifications approaches that of a new production line
When more than three core systems require simultaneous replacement, a full-line replacement option should be directly evaluated. Continuing with phased upgrades often increases the frequency of downtime, interface risks, and long-term maintenance costs.
Construction for the milk powder production line upgrade must be scheduled around the planned production shutdown window.
Pre-implementation tasks—such as site measurements, interface verification, equipment prefabrication, control program preparation, and construction simulations—should be completed beforehand. Assembly work (e.g., piping, supports, and control cabinets) that can be performed off-site should not be deferred until the shutdown period.
The logical implementation sequence is as follows:
1. Complete site surveys and retrofit designs.
2. Verify all interfaces between existing and new equipment.
3. Complete equipment manufacturing and prefabrication prior to the shutdown.
4. Dismantle old equipment and complete connections after the shutdown begins.
5. Inspect piping, instrumentation, interlocks, and safety devices.
6. Complete cleaning and no-load test runs.
7. Conduct trial production runs using actual raw materials.
8. Perform formal acceptance testing once stable operation is achieved.
Do not compress the time required for proper commissioning into the schedule for continuous production. Completion of installation does not equate to the production line having the capability for stable operation.
The completion of an upgrade project cannot be validated merely by the startup of equipment or the production of powder over a short period.
Formal acceptance testing must be conducted under agreed-upon raw material conditions, product specifications, and continuous operating durations, evaluating at least the following:
• Hourly output of qualified finished product
• Consumption of steam, electricity, and water per tonne of finished product
• Product yield and powder loss
• Moisture content of the finished product and its fluctuation range
• Target metrics such as solubility and bulk density
• Continuous operating duration
• Cleaning time and cleaning results
• Capability of the packaging process to continuously handle the entire output
The processing capacity committed to by the supplier must be clearly defined as either feed input rate, water evaporation rate, or qualified finished product output rate; these three figures must not be conflated.
To obtain an actionable proposal, the following information should be provided to the supplier:
• Existing process flow and equipment list
• Major equipment models, capacities, and service ages
• Recent actual production data
• Raw material composition and its range of variation
• Current product specifications and planned additions to the product line
• Actual utility supply capacities
• Plant dimensions, equipment layout, and available space
• Current bottlenecks, causes of downtime, and quality issues
• Target production output, energy consumption, and product specifications
• Permissible downtime
• Project budget and scheduled start-up date
If the information provided is incomplete, the supplier will have to base the design on assumptions. The more assumptions made, the greater the potential deviation in the upgraded system's actual capacity.
The correct sequence for upgrading an existing milk powder production line is: define upgrade objectives, establish production baselines, identify line-wide bottlenecks, select the appropriate modification strategy, verify compatibility between new and old systems, formulate a production shutdown plan, and finally conduct acceptance testing based on actual production results.
The most important principle is to avoid starting with equipment procurement or basing investment decisions on the rated capacity of individual machines. Only by first identifying the specific factors limiting the output of qualified finished products, energy efficiency, or quality—and then implementing upgrades with clearly defined acceptance criteria—can a predictable return on investment be achieved.
