MVR Evaporator Return on Investment (ROI) Calculation – Electricity Consumption, Steam, and Operation & Maintenance

MVR evaporators, as energy-saving evaporation and crystallization equipment, are widely used in fields such as zero wastewater discharge, resource utilization of high-salinity wastewater, and concentration of fine chemicals. Their return on investment (ROI) is a crucial factor in corporate decision-making. This article systematically breaks down the methods and key points for calculating the ROI of MVR evaporators, focusing on three core elements: power consumption, steam consumption, and operation and maintenance costs.

I. Basic Definition and Calculation Framework of ROI 

Return on Investment (ROI) Definition: 

ROI = (Annual Revenue Savings - Annual Operating Costs) / Initial Total Investment × 100% 

Key Calculation Elements: 

• Initial Total Investment (Equipment Purchase, Installation, Supporting Engineering, etc.) 

• Annual Cost Savings (Savings in Energy, Water Resources, Sewage Fees, Raw Material Recycling, etc.) 

• Annual Operation and Maintenance Costs (Electricity Consumption, Steam, Chemicals, Labor, Maintenance, Cleaning, etc.) 

• Equipment Lifespan (Generally, MVR evaporators are designed for a lifespan of 8-12 years) 

II. Power Consumption Analysis and Calculation

Main Sources of Power Consumption

• Compressor power consumption (core power-consuming equipment in MVR)

• Circulating pumps, feed pumps, discharge pumps, etc.

• Power consumption of cooling system, control system, and auxiliary equipment

Key Points for Power Consumption Calculation

• Compressor power (kW) × annual operating hours × electricity price (RMB/kWh) = annual compressor electricity cost

• Power of each type of pump × actual operating time × electricity price = annual pump electricity cost

• Generally, MVR evaporators consume 15~45kWh of power per ton of water evaporated, depending on the material properties, concentration ratio, and equipment design.

Energy Saving Advantages Comparison

• Compared to traditional multi-effect evaporation, although MVR power consumption is higher, steam consumption is significantly reduced, resulting in overall energy savings of 30~70%.

Example: A 10t/h MVR evaporator, operating for 8000 hours annually, consumes 30kWh of electricity per ton of water, with an electricity price of 0.8 yuan/kWh. Annual electricity cost = 10 × 30 × 8000 × 0.8 = 1.92 million yuan.

III. Steam Consumption Analysis and Comparison

MVR Evaporator Steam Consumption Characteristics

MVR evaporators require a small amount of live steam during startup, but consume almost no steam during normal operation, only compensating for heat loss.

Compared to multi-effect evaporators, steam consumption can be reduced by 0.3~0.6 tons per ton of water.

Steam Cost Calculation

Steam Cost per Ton (200-300 RMB/ton, depending on region and boiler efficiency)

Steam Savings × Steam Cost per Ton = Annual Steam Savings

Example Comparison: Multi-effect evaporator consumes 0.4 tons of steam per ton of water, MVR consumes only 0.05 tons of steam.

Evaporation capacity: 10t/h, annual operation: 8000 hours, steam price: 240 RMB/ton

Annual Steam Savings = 10 × (0.4 - 0.05) × 8000 × 240 = 6.72 million RMB

IV. Operation and Maintenance Cost Calculation

Main Operation and Maintenance Costs

Electricity Costs (see above)

Chemical Costs (scale inhibitors, cleaning agents, softeners, etc.)

Labor Costs (equipment monitoring, operation, and management labor costs)

Equipment Maintenance and Repair Costs (replacement of vulnerable parts, regular maintenance, CIP cleaning, etc.)

Water Costs, Cooling Costs, and other auxiliary costs

Operation and Maintenance Cost Estimate

Generally, the annual operation and maintenance cost of an MVR evaporator is approximately 5%-10% of the total equipment investment. Equipment and intelligent operation and maintenance can further reduce operation and maintenance costs.

Example: Total equipment investment of 10 million yuan, annual operation and maintenance rate of 8%, annual operation and maintenance cost = 800,000 yuan

V. Comprehensive ROI Calculation Case

Project Conditions:

Total investment of MVR evaporator system: 10 million yuan

Annual steam cost savings: 6.72 million yuan (compared to multi-effect evaporation)

Annual electricity consumption cost: 1.92 million yuan

Annual operation and maintenance cost: 800,000 yuan

Equipment life: 10 years

Annual net income = Annual steam cost savings - Annual electricity consumption cost - Annual operation and maintenance cost

= 6.72 - 1.92 - 80 = 4 million yuan

Investment payback period = Total investment / Annual net income = 1000 / 400 = 2.5 years

ROI (10-year cycle) = (400 × 10 - 1000) / 1000 × 100% = 300%

VI. Key Factors Affecting ROI and Optimization Suggestions

Electricity consumption optimization: Select high-efficiency compressors, variable frequency drives, and optimize process flow to reduce electricity consumption per ton of water. Refined Operation and Maintenance: Automated monitoring, online cleaning, and preventative maintenance extend equipment life and reduce downtime losses.

Resource Recovery Gains: Recovering salts, organic matter, and distilled water enhances overall profitability.

Policy Subsidies and Environmental Benefits: Emission reduction rewards, zero wastewater discharge subsidies, and savings in sewage fees are incorporated into economic calculations.

Equipment Selection and Engineering Design: Based on water quality and operating conditions, appropriate types and materials are selected to avoid over-investment or frequent failures.

VII. Conclusion 

Calculating the return on investment (ROI) of MVR evaporators requires considering three core factors: power consumption, steam savings, and operation and maintenance costs. Scientific design and refined operation and maintenance can significantly shorten the investment payback period and improve long-term economic benefits. Combined with resource recovery and environmental policies, MVR evaporators possess excellent economic benefits and sustainable development advantages. Enterprises should conduct detailed technical and economic evaluations based on their own circumstances, select the best system solution, and maximize ROI.