【 Weak current College 】 heating ventilating and air conditioning cooling water treatment status, problems and solutions (2)

The new standard for relaxed 4.2 water hardness indicators

New standard "industrial boiler water quality" (GB1576-2001), hot water boiler feed water treatment with chemical water treatment relaxes the hardness of the water supply. The original standard GB1576-1991 provides water hardness ≤ 4mmol/L, the new standard in 2001 GB1576-water hardness ≤ 6mmol/L-while most of the water hardness is around 6mmol/L (Tianjin Luan water hardness about 3.4mmol/L, pH = 7, dissolved oxygen 10mg/L). This water as a carrier of heating, air conditioning, cooling water circulation system, to use chemical water treatment method has very favorable conditions. In other words, most of China's hot water heating system, air conditioning, hot and cold water system can use chemical treatments of water. Because this can reduce the hardness of the water as the primary purpose of sodium ion exchange method, which creates a significant amount of each year, hundreds of tons of waste salt contamination of groundwater.

5 air conditioning and refrigeration, HVAC and water treatment design

Collect water quality data 5.1

Design for water treatment, you should first collection system water quality information, such as hardness, pH, dissolved oxygen, chlorine ions, dissolved solids (or salt content), suspended solids, etc. In order to provide engineering design to address the water circulation system prevalence of corrosion or scaling phenomena provide the underlying data.

5.2 understanding system equipment and materials, material

Should identify or understanding system equipment, piping, valves, pumps, and other materials used to meet the design requirements on water quality and water treatment, and prevention of corrosion and fouling system.

5.3 hot and cold water system water treatment process

Hot water heating system, air conditioning, hot and cold water system water treatment programme, first use of advanced technology and proven methodof water treatment automatic dosing device on the system of automatic dosing of chemical water treatment methods. Single use sodium ion exchanger production of demineralized water only prevent system scaling, not corrosion prevention system, air-conditioning, hot water corrosive than tap water. This is because the tap water contains calcium carbonate, natural, it is a cathode resistance of corrosion inhibitors. When water softening, while increasing the pH of the water, but as hardness constituents of removal, the water's original natural inhibitor calcium carbonate-has also been removed; coupled with the sodium ion exchanger for softening water salinity than raw water has increased, its calculation formula is:

ΔG=2.95HCa+10.84HMg

G-Δ-softened water salinity increase, mg/L; HCa-raw water hardness Ca, mmol/L; HMg-raw water hardness Mg, mmol/L.

Therefore, single use sodium ion exchanger manufacture of softened water, dosing chemicals to prevent the system from corrosion. This approach will make the sodium ion exchanger produces large amounts of recycled waste and contaminated groundwater saline solution, and will make the device a total investment of more than a chemical compound of pharmaceutical methods of water treatment equipment. Moreover, the use and circulation of cold and hot water system that corresponds to the characteristics of chemicals for water treatment, its running cost is lower. It is also a pollution-free, green environmental protection product should be vigorously promoted.

To physical methods of water treatment, such as a magnetic water, electronic water treatment device, to a certain quality of a scale effect, but does not have the effect of preventing corrosion, thus making the system experienced a severe corrosion. A commercial installation 2 Hitachi brand screw chillers, and run a few years after the discovery of serious corrosion of the equipment and pipeline, the physical water treatment facilities. In early 2002,the original of the "electronic water treatment" and all the corroded pipe complete demolition, removal process discovery pipeline has a large number of rust and iron oxide. So screw chillers also made chemical cleaning. After the switch to the "chemical methods of water treatment programme", the use of automatic dosing equipment, air-conditioning and hot water systems and cooling water systems, implementation of the chemical water treatment, for the second year running to receive good results.

5.4 cooling water system water treatment process

To prevent cooling (or air pressure, air separation) water systems, environmental impact, so that the cooling water mixed with a lot of dust, bacteria, oxygen, sulphur dioxide, nitrogen oxides, acid rain, pollution, and because of the evaporative cooling water continuously, the original water Ca2 + in, Mg2 +, Cl-, SO42-and dissolved solids, total suspended matter concentration continues to increase, resulting in the cooling water system of corrosion, dirt and bacteria and algae reproduction that produce clay and blocked pipeline or equipment. It is designed to be the preferred method of "chemicals" water treatment programme. From currently available technology, adopt and cooling water system features correspond to conduct water treatment chemicals, more than any other method is more effective, in line with existing State Bureau of technical supervision and construction Ministry published national standards. The method from the GB (GB50050-95) — "industrial cooling water treatment design specifications" and "industrial circulating water cooling design standard" (GB/T50102-2003), better than any other.

5.5 should strictly control system and sufficient water for the first time and run time for water quality

If the first filled with water or tonic water does not comply with the requirements, system equipment, pipeline causing corrosion. Even stainless steel equipment (e.g., SUS304, SUS316, material), such as the Cl-ions concentration is too large, it will give rise to corrosion even causing perforation equipment.

6, HVAC and refrigeration and air conditioning water treatment technology prospect

6.1 break tradition, the use of new technologies for water treatment, everyone from a Green perspective in the design, construction, management, quality homes.

6.2Appealed to the relevant departments to develop policies and regulations, development, production more affordable green chemical water treatment chemicals, to adapt the protection of the environment. No phosphorus (p), non-toxic green chemical water treatment chemicals, in hot water heating system, air conditioning, hot and cold water and cooling water systems using proven, has on the environment, pollution-free, non-destructive of good results, its running cost and containing organic phosphonic acid salt scale, corrosion inhibition reagents. Of particular note is the operation of the sewage will not cause environmental pollution.

6.3 water treatment automatic dosing device is achievable on the circulating water system automatically or timing of dosing, to reduce the labor intensity of workers. The device according to the number of water supply, Proportioning of automatic dosing or timing of dosing, according to the water's pH and water supply on-line control of quantitative dosing. We want to continue to develop advanced technology, easy operation, price/performance advantages of automatic water treatment dosing equipment, to promote the HVAC and refrigeration and air conditioning industry for the development of chemical water treatment.