Waste-to-energy industry prospects

At present, China's domestic waste treatment mode is mainly based on sanitary landfill.

There are two main types of domestic garbage disposal: sanitary landfill and incineration. Sanitary landfill is a comprehensive method based on the principle of natural degradation of waste, using strict scientific management methods to prevent waste from polluting the surrounding environment. The investment cost is low and the requirements for garbage are low; the disadvantage is that the occupied land area is large, and leakage may occur, causing secondary pollution. Waste incineration refers to placing the garbage in a high temperature environment above 850 degrees Celsius, so that the active components in the garbage are oxidized and converted into stable residues, releasing heat and used for heat supply and power generation. The advantage is high energy utilization efficiency and environmental impact. Small, small footprint; shortcomings are large initial investment and high technical requirements.

The proportion of landfill methods is declining. The proportion of incineration is rising year by year.

Historically, landfill has been the mainstream model, but in recent years, the proportion of landfill waste has continued to decline, from 78% in 2010 to 60% in 2016, and to about 55% in 2017. China's landfill-based waste treatment structure will gradually shift to incineration. On the one hand, due to the current rising trend of land prices in cities across China, the cost of landfills is rising, and on the other hand, the urbanization rate is causing urban land shortage, and the supply of infrastructure land is shrinking. Landfills The land is limited. The treatment of landfill landfills has been squeezed by both the volume and price of the land market, and the share in the waste disposal market has gradually narrowed.

With policy support, future incineration and power generation will be the mainstream mode of domestic waste disposal.

In the future, waste incineration power generation technology will gradually develop into a mainstream way of waste disposal in China. In 2020, the incineration treatment mode is expected to account for 54% of domestic waste treatment. During the 13th Five-Year Plan period, the waste incineration power generation industry will continue to grow, but the growth rate will gradually slow down; according to the “13th Five-Year Plan”, the new incineration capacity will continue to be concentrated in the eastern coastal areas and the average project size will be relatively large, and Gradually moved to the central and western regions and second- and third-tier cities, but the average size of the project has declined. On the business model, waste incineration has extended from traditional BOT to DBO, O&M, EPC, etc. In the future, it will gradually develop into a PPP model and move to integrated environmental services.

The biggest advantage of this method is that it reduces waste discharge. The waste incineration plant is built around the city, which is convenient for transporting garbage and providing electricity and heat to the city, which has produced good economic benefits. Waste incineration power generation has become a major channel for the disposal of domestic waste in the current economic powers and an important part of the power industry.

Energy-saving analysis of frequency conversion speed regulation technology

The most commonly used control method in power plant production and operation is to adjust the size of the valve, damper and baffle opening to adjust the pump and fan type rotating equipment. In this way, regardless of the size required for production, the fan should operate at a fixed speed according to the quantity. Changes in operating conditions can cause energy loss due to throttle, baffle, and baffle throttling losses. In the production process, not only the control accuracy is limited, but also a large amount of energy waste causes equipment loss. Thereby increasing the production cost, shortening the service life of the equipment, and improving the maintenance of the equipment. Most of the fan and pump equipment are operated by asynchronous motor. The starting current has the disadvantages of large mechanical impact and poor electrical protection. Not only the service life of the equipment is affected, but also the load of the equipment is affected. When the machine fails, the equipment cannot run immediately. Damage to the pump and burnout of the motor often occur.

In recent years, due to the urgent need for energy saving and continuous improvement of product quality requirements, coupled with the inverter's ease of use, maintenance-free, high control precision, and strong functions; therefore, it is driven by the inverter. Begin to gradually replace the control scheme of the damper, baffle, valve and fluid.

According to the basic law of fluid mechanics, the fan and pump equipment are square torque loads, and the speed, pressure and shaft power P of N and flow Q have the following relationship: Q ∝ n2, H ∝ n2, P∝n3; And the speed becomes the axis power proportional to the cube of the speed. The use of variable frequency speed control technology to change the motor speed is more economical than the use of valves and baffles, and the equipment operating conditions can be significantly improved.

According to the operating experience, the actual operating conditions of the fan in a general power plant are worth about 80% of its rated value. For example: the actual operating condition of a fan is 80%, and its speed is reduced by 20%. According to the above physical relationship, the power of the fan is about (0.8)3≈0.51. If other factors are removed, the fan is nearly 40%. The power is wasted. If the total power of the induced draft fan, primary fan and secondary fan in the waste incineration power plant is 885 kW, and the unit is calculated at 8000 hours per year, the plant power can be saved as 885 kWx x8000hx x40% 283 2832000 kW·h. Electricity price subsidy, assuming that the on-grid price is 0.38 yuan / kW · h, monthly electricity savings of 0.38 yuan / kW · hx x 2832000kw · h ÷ December ≈ 96.60 million / month. The one-time investment per kilowatt is about 0.2 million yuan / kW, that is, 0.2 million yuan / kWx x 885kW ≈ 1.77 million yuan, the investment recovery period = total investment / monthly power saving benefit = 1.77 million yuan / 89,600 yuan = 19.8 months, that is The cost can be recovered in less than 2 years.

Occasion of application of frequency converter in waste power plant

The frequency converter is widely used in all walks of life, and the consistent reaction effect is good after use. It has both social effects and economic benefits. Then the waste power plant can also apply the frequency converter. According to the process requirements, the frequency converter can be applied to the following various equipments. On, for example: induced draft fan, blower, various pumps, exhaust fan, rotary kiln drive, belt conveyor, sorting fan, crane, etc., through the application of the frequency converter can achieve speed control (process needs), energy saving ( Reduce the consumption, reduce the cost), achieve soft start, soft brake, improve the level of automation, etc., so the frequency converter is used in all the process equipment of the completed waste power plant.