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Energy consumption and conservation in tea processing in China
Renewable Enery) Vol. 2, No. I, pp. I 5. 1992 Printed in Great Britain.
0960 1481/92 $5.00+.00 Pergamon Press Ltd
E N E R G Y C O N S U M P T I O N A N D C O N S E R V A T I O N IN TEA P R O C E S S I N G IN C H I N A Jl QIN NI* a n d HANG ZHOU Hangzhou Rural Energy Office, No. 1 Qingtai Street, Hangzhou, Zhejiang Province, 310016, P.R. China
(Received 28 November 1990 ; accepted 7 N'~vember 1991) Abstract--Energy consumption in tea processing in China reached 860,000 tons of coal equivalent in 1988 (2.93 G J/ton), most of which was provldcd by biomass. The paper deals with tea production and processing and their energy consumption in 17 provinces, types of tea and associated problems, such as waste of energy, bad ecological effects and the high cost of tea production. The paper also deals with measures to solve the energy problems in tea processing and lists five energy saving techniques in the process. INTRODUCTION Tea is one of the main drinks in the world. In recent decades, the tea consumption per capita in the globe increased steadily and reached 0.43 kg/year in 1983, double the amount of 1950. China is one of the principal tea producing countries. It produced 508,000 tons of dry tea in 1988, ranked second in the world. In 1987 it exported 174,000 tons, ranked third in the world. In China, tea is one of the main export agricultural products, and also one of the chief cash crops. However, tea processing consumes a large amount of energy. In 1988, the total energy consumption in tea processing in China reached 860,000 tons of C E (Coal Equivalent : 2.93 GJ/ton), most of them provided by biomass. With the rapid increase of tea production, the rural energy consumption in tea processing rises sharply. Thus, the problems of large amount of firewood consumption, of big energy waste and of poor management become even more urgent and must be studied and solved.
duce some 60 per cent of tea of the whole nation, and in consequence, consume most of the tea processing energy. Both tea production and energy consumption in China have increased greatly since 1949 when total tea production was only 46,000 tons and energy consumption in tea processing was only 93,700 tons of CE. In 1980 the tea production reached 304,000 tons while energy consumption got to 555,000 tons of CE, 4.8 times more than that of 1949. After 1980, tea production increased even more rapidly. F r o m 1980 to 1988, it registered an annual average increase rate of 7.61% and the processing energy increased at the same time. Refer to Fig. 1. 800
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The energy consumption in tea processing in rural China relates to tea products, varieties of tea, tea processing equipment and so on.
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TEA PRODUCTION, TEA PROCESSING, AND ITS ENERGY CONSUMPTION IN CHINA
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Geographical distribution of tea and increase of tea products concernin 9 eneryy consumption There are 17 Provinces growing tea, and they are all situated in southern part of China. A m o n g them, Zhejiang Province produces the most, next come Hunan, Sichuan and Anhui Provinces. The four pro* Current address : Unit of Bioengineering, Place Croix du Sud 2/19, 1348 Louvain-la-Neuve, Belgium.
• 200
100
0 1940
•
J 1950
•
, 1960
•
, 1970
•
i 1980
,
i
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1990
Year
Fig. 1. Tea production and total energy consumption in China.
2
Jl QIN N! and HANG ZHOU
Also the ever increasing tea production seems to be undergoing a change from 1987, it has already given tea processing energy a more and more important place in rural energy in many tea growing areas. In 1985, the tea processing energy in Zhejiang Province reached 150,000 tons of CE. In Hangzhou Prefecture in the same province, rural tea processing energy makes up 24% of the total agricultural by-products processing energy, or 7% of all energy used in rural production of the whole region.
Energy used in tea processing There are mainly three kinds of energy used in rural tea processing in China. The first one is biomass--firewood, which has a longest history in rural tea processing in China, and is now still the most significant energy source in the majority of the tea growing areas. In Zhejiang Province, firewood accounts for 75% of the total energy used in rural tea processing. In Fujian, Anhui and Hunan Provinces firewood also holds the most important position in tea making. Firewood, most of which cut in local forests, is used to provide heat for de-enzyme and drying through combustion in hand preparation and in rural small tea processing factories. It is estimated that the whole nation consumed about 943,400 tons of firewood for this purpose in 1988, equals 62.66% of total energy consumed in tea processing. The second kind of energy is coal. Coal provides heat for de-enzyme and drying the same as firewood. It is used in large and medium sized tea factories in areas where it is available. Coal is distributed with planning and delivered with long transportation in areas where it is not a local resource. In these areas, coal can still not meet the needs of tea processing. In rural areas in Zhajiang, coal amounts to only 23% of the total energy used in tea processing. The coal consumption for tea processing is estimated to be 365,100 tons in whole China in 1988, 30.31% of the total energy consumed. The third kind of energy is electricity. Electricity provides power for apparatus of tea processing. In recent years, electricity heating apparatus also comes into use. The electricity consumption in tea making of the whole country was about 1,493,000 kWh in 1988, 7.03% of the total energy consumed in tea processing. Refer to Fig. 2.
Types of tea and sections of processing concerning energy consumption Green tea, black tea and specialist tea are the three main types of tea in China. Different types of tea need different processing methods and consumed different amount of energy. Tea processing falls into two parts :
soo] •
Firewood
mmco~
•
Electr~t,y"
600
soo
~ 3oo uJ 200
100
o I g8o 1981 1 9 8 2 1 9 8 3 1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 g88
Year
Fig. 2. Different kinds of energy consumed.
the first preparation and the finish machining. The first preparation consumes most of the processing energy and is chiefly done in rural areas in China. De-enzyme, rolling and drying are three sections of green tea processing, which consume 47%, 1% and 52% of the total energy, respectively. According to various reports, making 1 kg of green tea consumes 1.5-2.3 kg of CE, an average of 2.04 kg. It is the highest among all types of tea. In recent years, the green tea product amounts to 55-59% of the gross tea product. It is thus the biggest energy-consuming type of tea. The sections of first preparation of black tea are withering, roiling, fermenting and drying. Among them, drying also consumes the most of the energy, amounting to some 70%. 1.27 kg of CE is estimated in making 1 kg of black tea. Black tea product made up 26.9% of the gross tea product in 1986 in China. The making of all other special types of tea includes drying. In first preparation, 1.41 kg of CE is needed for 1 kg of special tea. The structure of tea types is gradually changing. From 1980 to 1986, the proportion of green tea dropped from 58.6% to 55.9%, while that of black tea increased from 23.4% to 27.0%. This is also one of the factors which affect energy consumption.
Apparatus for tea processing and energy consumption There are two kinds of apparatus for tea processing in China: hand preparation apparatus and tea processing machines.
Energy consumption and conservation in tea processing in China Apparatus for hand preparation, usually small and simple stoves with frying pans, provides only heat power, and has a low productivity as well as a high energy-consumingrate. With the development of various tea processing machines, this kind of apparatus is no longer used as the main one. Tea processing machines, relatively higher productivity and lower energy consumption, have varieties of types. It can now meet the requirements of almost all sections of first tea preparation except for a few special types of tea. But energy efficiency differs among different types of machines. The apparatus provides not only heat but also power for tea agitating and rolling and therefore consume both fuel and electricity. Tea machines are now being widely used in the main tea growing areas in China.
3
Machines, the lowest was only 49% of the highest. In another region: Yingshan County, Hubei Province, the old type of tea baking stoves there wasted 40% of energy compared with the energy-efficient stoves. The second cause of energy waste is poor management. Under the same equipment conditions, the consumption of coal in processing 1 kg of tea is 36% more in Xishan Tea Factory of Yuhang County, Zhejiang Province than in other factories because of the poor management. In a sampling survey made in Anhui Province, it was discovered that among three different management ways, the energy consumption of I kg of tea of Unified-processing was 1.9 kg of coal, while that of Collective Processing was 4.5 kg of coal, and Separated-family-processing was 4.7 kg of coal. The latter consumed 142% more coal than that of the first.
PROBLEMS PRESENTED
Large energy waste, bad ecological effect and hindering tea production are three main problems confronted with in tea processing in rural China. Large waste ~)f enerqy The main causes of energy waste in tea processing are as follows. The first one is low energy efficiency apparatus in tea processing. According to a survey of 17 tea processing plants in 1984 made by Hangzhou Tea High Quality and Energy Conservation Cooperatives Group, the energy efficiency of several types of tea processing apparatus, calculated by the Method of Water Evaporating, differed very much. This showed that many low efficiency machines are still in operation in this area. Table 1 indicates that among the surveyed Trough Shaped Green Tea Sterilizers, the energy efficiency of the lowest was only 31% of that of the highest. While among the Bottle Shaped
Bad ecological effect There are both severe shortage and big waste of firewood resources in most of the Chinese rural areas. According to an investigation in five provinces (Sichuan, Yunnan, Guizhou, Hunan and Jiangxi), the forest resources consumed by wood production accounted only for 15 33%, while that used as firewood made up 47-64%. Tea processing in rural areas uses a large amount of firewood, which makes the shortage of rural energy even more severe and speeds up deforestation. In Yingshan County, Hubei Province, 9,000 tons of firewood is needed every year for tea baking, equals an annual productivity of 36,000 mu (5,929 acres) of forest. In some mountain areas in Zhejiang Province where forest has been damaged rather severely, the villagers still cut 4 tons of firewood for making 1 ton of tea. Moreover, the firewood for tea processing is usually log, much better than cooking firewood which is usually small branches and leaves
Table 1. Survey of energy efficiencyof tea processing machines in 17 plants in Hangzhou Prefecture
Types of machines Trough-shaped green tea sterilizer Rolling-barrel green tea sterilizer Double-pan continuing green tea sterilizer Bottle-shaped machine Drying machine
Number of machines surveyed
Average water evaporated" (kg)
Maximum water evaporated" (kg)
Minimum water evaporated° (kg)
5
3.05
4.25
1.30
5
2.39
2.94
1.79
6
1.96
2.60
1.56
19 20
2.27 1.79
5.34 1.84
1.11 1.00
"Water evaporated by burning 1 kg of coal (20,900 J/kg). Source : The Agricultural Bureau of Hangzhou Prefecture, Zhejiang Province (1984). Summary of the Second Conference ¢71Hangzhou Tea High Quality and Energy Conservation Group, March, 1984.
JI Q1N NI and HANGZHOU in these areas. Thus it has caused a greater negative effect on forest resources.
Ra&in9 the cost of tea and h&derin9 the development of tea production The large amount of energy consumption makes up a certain part of the tea processing cost. In some regions it reaches about 10-15% of the gross cost of tea, equals the costs of fertilizer and pesticide in tea growing. Moreover, tea production is effected by the shortage of energy in some tea growing regions. Besides the market, energy is one of the main factors that hinders tea production.
MEASURES TAKEN TO SOLVE ENERGY PROBLEMS IN TEA PROCESSING
Tea has a rather important position in rural economy in China. If the tea production is to be developed, the problems of energy must be solved. This has already attracted more and more attention in recent years and much effort has been made in energy conservation.
A brief history of energy conservation in tea processing Although tea making has a rather long history in China, its energy saving was not largely considered until about ten years ago. In 1950s and 1960s the energy consumption in tea processing was almost totally ignored. In 1970s energy saving in rural areas began to take place especially in firewood saving in the daily life (by using energy efficiency stoves), but not in tea production yet. With a heavy burden of the increasing rural population, the rural biomass energy resources could not meet the needs of both living and production, and caused a severe problem of deforestation. Since the beginning of 1980s, efforts were made in order to reach an economic and ecological goal. At first, technical researches were carried out, pilot programs were launched. Later regional projects were gradually established. In Hangzhou Prefecture, a three-year-plan was made in 1988 in order to improve 80% of the existing tea processing stoves and machines. In May 1989, the first National Conference on Energy Conservation on Tea Production organized by the Ministry of Agriculture was held in Hangzhou, Zhejiang Province. It promotes largely the activities in this field in the whole nation. Under the Ministry of Agriculture, different institutions are involved in the campaign. Among them are : - - T h e Agricultural Bureaus in the levels of province, prefecture and county, usually there is a division
in charge of tea production technologies in each Bureau ; - - R u r a l Energy Offices in different levels, to them the main task assigned is the R/D of rural energy saving and exploitation technologies ; --Local Supply and Marketing Cooperatives which are involved in the tea market. There are also others not under the direct leadership of the Ministry of Agriculture, namely : --Institutes and factories relating to tea machine design and fabrication ; ---Coal companies that supply part of the fuel for tea making.
Efforts made for energy conservation It is estimated that the potential of energy conservation in tea processing is about 220,000 tons of CE a year in rural China. In order to realize the energy saving goal, effective effects have been made in recent years in different regions and different levels. Scientific research and technical innovation are carried out with good results, giving the possibilities to technical improvement of the equipments. Surveys and studies are made for regional planning and policy making. Investments are usually given in different levels: local governments, organizations, rural communes and users. Among them, investments of local governments and organizations are mostly used for research, development and diffusion, while that of rural communes are usually given as subsidies to the users. But these investments are not always available in all regions. Diffusion is also an important part of the work done. Many technical visits are made and technical training courses are held in different levels. Technically, the efforts made for energy saving in tea processing can be summarized as follows : 1. Stove improvement. It is to improve the fuel burning system of fire box as to raise the energy efficiency of the apparatus. It is technically simple, low cost and effective. Improved stoves can raise energy efficiency up to 20-50% compared with that not improved. The cost of the reform can usually be recovered within 12 years. 2. Machine improvement. Comparatively complex and usually done in tea processing machine-making factories, it is to reform the heat-utilizing system in order to raise the heat efficiency. The energy saving rate can usually reach 15-20%. The machines improved are mostly big and medium size tea processing equipment, and therefore have a good result of energy conservation.
Energy consumption and conservation in tea processing in China Table 2. Results of energy saving by adjusting matching power motor of tea machines
Type of machines 6CS-70 Trough shaped green tea sterilizer 6CYS-40 Plane-round screen machine Screen machines conveyer 6CED-45 vibrate screen machine 6CZS- 120 Color-making machine 6CRQ-30 Rolling machine
Original motor power (kW)
Maximum power consumption measured (kW)
1.5
Motor power adjusted (kW)
Energy saving (%)
1.1
27
1.1
0.36
0.8
27
0.55 1.1
-0.4
0.37 0.8
33 27
2.2
0.93
1. l
50
10.0
6.0
7.5
25
Source: Tea Machine Design and Research 4 (1986).
3. Matching power adjustment. It is to adjust m a t c h i n g power o f m o t o r s for tea machines. It is reported that a n overall power d e t e r m i n a t i o n of some tea processing m a c h i n e s revealed a waste o f power of the motors, which is 1.6-3.5 times as m u c h as the m a x i m u m power needed. W h e n the m a t c h i n g m o t o r s were replaced, 2 5 - 5 0 % of the power was saved. See T a b l e 2. 4. Heat using system improvement. In ways o f heat utilization, centralized-heat-providing is energy efficient. In this system, the high temp heat from the b u r n e r is used by the high temp processing section to de-enzyme tea at first, a n d then the wasted low temp heat is used to the low temp processing s e c t i o n - drying. T h e 6 C M C L - 1 0 M o d e l G r e e n Tea First Prepa r a t i o n Set, developed by Z h e j i a n g Agriculture University (1987), using the m e t h o d of Multiple-machines-one-stove, can save 4 0 - 5 0 % o f fuel. 5. By improving management in tea processing. A m o n g the various m a n a g e m e n t ways, unified mechanical processing is m u c h more energy efficient t h a n decentralized m a n u a l processing. In Nigdu Prefecture, Fujian Province, unified first p r e p a r a t i o n o f tea cut d o w n m o r e t h a n a half o f the fuels a n d electricity, the former also saved m a n p o w e r , raised tea quality a n d h a d a better profit. The survey m a d e in H u i z h o u Prefecture, A n h u i Province, proved the same p h e n o m enon. REFERENCES
1. Anonymous, Recent development of the improvement of the Horizontal-pipe Hot Air Stove for tea drying machine. Tea Machines Design and Research 3 (1987). 2. S. Chen, Research on the prospects of tea machine making industry in Zhejiang Province. Tea Machines Design and Research 3 (1987).
3. Z. Fang, Tea Making Double-Stove .[or Saving Enerqy and Raising Tea Quality. Report (1988). 4. The Agricultural Bureau of Hangzhou Prefecture, Zhejiang Province. Summary of the Second Conference of Hangzhou Tea High Quality and Energy Conservation Group (1984). 5. W. He, Saving tea making energy. Tea Bulletin 3 (1984). 6. P. Hu, On the problem of tea-making energy conservation in Zhejian Province. Tea 3 (1983). 7. International Tea Committee. Annual Bulletin of Statistics (1982, 1984, 1986, 1988). 8. L. Jing and P. Lu, Report on the survey of utilization of forest energy in southern China. Proceedings of the Symposium of Forest Energy (1981). 9. J. Liu, A new energy saving stove for tea baking. Tea Bullethls 2 (1987). 10. P. Liu et al. Tea Cultivating and Tea Processing. Guandong Science and Technology Publishing House of China (1983). 11. R. Liu and X. Zhuo, Some remarks on solving the energy problems in tea processing in east Fujian Province. Tea Bulletins 6 (1983). 12. National Statistics Bureau, Yearbook ~f Rural Statistics of China o[1986 (1986). 13. K. Pan, Selection of motor powers for tea processing machines. Tea Machines Design and Research 4 (1986). 14. P. Shuai, The Total Quality Control (TQC) in Mei Tea fine making factories. Tea Bulletins 1 (1986). 15. G. Wang, The development of tea production in China. Tea Bulletin 3 (1987). 16. S. Wang, Tea economics. China Tea 6 (1982). 17. D. Xia, The modernization of green tea first preparation machines. Tea Machines Design and Research 4 (1986). 18, G. Yu, Establish a new system of tea circulation by cooperating and improving first preparation. Tea Bulletin 1 (1987). 19. Y. Yuan, Innovation of the stove of the tea drying machine. China Tea 4 (1982). 20. X. Zhuang, Research on the anticipation of tea development during the period of Seventh Five-year-plan. Tea Bulletin 1 (1986).
0960 1481/92 $5.00+.00 Pergamon Press Ltd
E N E R G Y C O N S U M P T I O N A N D C O N S E R V A T I O N IN TEA P R O C E S S I N G IN C H I N A Jl QIN NI* a n d HANG ZHOU Hangzhou Rural Energy Office, No. 1 Qingtai Street, Hangzhou, Zhejiang Province, 310016, P.R. China
(Received 28 November 1990 ; accepted 7 N'~vember 1991) Abstract--Energy consumption in tea processing in China reached 860,000 tons of coal equivalent in 1988 (2.93 G J/ton), most of which was provldcd by biomass. The paper deals with tea production and processing and their energy consumption in 17 provinces, types of tea and associated problems, such as waste of energy, bad ecological effects and the high cost of tea production. The paper also deals with measures to solve the energy problems in tea processing and lists five energy saving techniques in the process. INTRODUCTION Tea is one of the main drinks in the world. In recent decades, the tea consumption per capita in the globe increased steadily and reached 0.43 kg/year in 1983, double the amount of 1950. China is one of the principal tea producing countries. It produced 508,000 tons of dry tea in 1988, ranked second in the world. In 1987 it exported 174,000 tons, ranked third in the world. In China, tea is one of the main export agricultural products, and also one of the chief cash crops. However, tea processing consumes a large amount of energy. In 1988, the total energy consumption in tea processing in China reached 860,000 tons of C E (Coal Equivalent : 2.93 GJ/ton), most of them provided by biomass. With the rapid increase of tea production, the rural energy consumption in tea processing rises sharply. Thus, the problems of large amount of firewood consumption, of big energy waste and of poor management become even more urgent and must be studied and solved.
duce some 60 per cent of tea of the whole nation, and in consequence, consume most of the tea processing energy. Both tea production and energy consumption in China have increased greatly since 1949 when total tea production was only 46,000 tons and energy consumption in tea processing was only 93,700 tons of CE. In 1980 the tea production reached 304,000 tons while energy consumption got to 555,000 tons of CE, 4.8 times more than that of 1949. After 1980, tea production increased even more rapidly. F r o m 1980 to 1988, it registered an annual average increase rate of 7.61% and the processing energy increased at the same time. Refer to Fig. 1. 800
~
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The energy consumption in tea processing in rural China relates to tea products, varieties of tea, tea processing equipment and so on.
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=
700
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600
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TEA PRODUCTION, TEA PROCESSING, AND ITS ENERGY CONSUMPTION IN CHINA
,
1000
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Geographical distribution of tea and increase of tea products concernin 9 eneryy consumption There are 17 Provinces growing tea, and they are all situated in southern part of China. A m o n g them, Zhejiang Province produces the most, next come Hunan, Sichuan and Anhui Provinces. The four pro* Current address : Unit of Bioengineering, Place Croix du Sud 2/19, 1348 Louvain-la-Neuve, Belgium.
• 200
100
0 1940
•
J 1950
•
, 1960
•
, 1970
•
i 1980
,
i
0
1990
Year
Fig. 1. Tea production and total energy consumption in China.
2
Jl QIN N! and HANG ZHOU
Also the ever increasing tea production seems to be undergoing a change from 1987, it has already given tea processing energy a more and more important place in rural energy in many tea growing areas. In 1985, the tea processing energy in Zhejiang Province reached 150,000 tons of CE. In Hangzhou Prefecture in the same province, rural tea processing energy makes up 24% of the total agricultural by-products processing energy, or 7% of all energy used in rural production of the whole region.
Energy used in tea processing There are mainly three kinds of energy used in rural tea processing in China. The first one is biomass--firewood, which has a longest history in rural tea processing in China, and is now still the most significant energy source in the majority of the tea growing areas. In Zhejiang Province, firewood accounts for 75% of the total energy used in rural tea processing. In Fujian, Anhui and Hunan Provinces firewood also holds the most important position in tea making. Firewood, most of which cut in local forests, is used to provide heat for de-enzyme and drying through combustion in hand preparation and in rural small tea processing factories. It is estimated that the whole nation consumed about 943,400 tons of firewood for this purpose in 1988, equals 62.66% of total energy consumed in tea processing. The second kind of energy is coal. Coal provides heat for de-enzyme and drying the same as firewood. It is used in large and medium sized tea factories in areas where it is available. Coal is distributed with planning and delivered with long transportation in areas where it is not a local resource. In these areas, coal can still not meet the needs of tea processing. In rural areas in Zhajiang, coal amounts to only 23% of the total energy used in tea processing. The coal consumption for tea processing is estimated to be 365,100 tons in whole China in 1988, 30.31% of the total energy consumed. The third kind of energy is electricity. Electricity provides power for apparatus of tea processing. In recent years, electricity heating apparatus also comes into use. The electricity consumption in tea making of the whole country was about 1,493,000 kWh in 1988, 7.03% of the total energy consumed in tea processing. Refer to Fig. 2.
Types of tea and sections of processing concerning energy consumption Green tea, black tea and specialist tea are the three main types of tea in China. Different types of tea need different processing methods and consumed different amount of energy. Tea processing falls into two parts :
soo] •
Firewood
mmco~
•
Electr~t,y"
600
soo
~ 3oo uJ 200
100
o I g8o 1981 1 9 8 2 1 9 8 3 1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 g88
Year
Fig. 2. Different kinds of energy consumed.
the first preparation and the finish machining. The first preparation consumes most of the processing energy and is chiefly done in rural areas in China. De-enzyme, rolling and drying are three sections of green tea processing, which consume 47%, 1% and 52% of the total energy, respectively. According to various reports, making 1 kg of green tea consumes 1.5-2.3 kg of CE, an average of 2.04 kg. It is the highest among all types of tea. In recent years, the green tea product amounts to 55-59% of the gross tea product. It is thus the biggest energy-consuming type of tea. The sections of first preparation of black tea are withering, roiling, fermenting and drying. Among them, drying also consumes the most of the energy, amounting to some 70%. 1.27 kg of CE is estimated in making 1 kg of black tea. Black tea product made up 26.9% of the gross tea product in 1986 in China. The making of all other special types of tea includes drying. In first preparation, 1.41 kg of CE is needed for 1 kg of special tea. The structure of tea types is gradually changing. From 1980 to 1986, the proportion of green tea dropped from 58.6% to 55.9%, while that of black tea increased from 23.4% to 27.0%. This is also one of the factors which affect energy consumption.
Apparatus for tea processing and energy consumption There are two kinds of apparatus for tea processing in China: hand preparation apparatus and tea processing machines.
Energy consumption and conservation in tea processing in China Apparatus for hand preparation, usually small and simple stoves with frying pans, provides only heat power, and has a low productivity as well as a high energy-consumingrate. With the development of various tea processing machines, this kind of apparatus is no longer used as the main one. Tea processing machines, relatively higher productivity and lower energy consumption, have varieties of types. It can now meet the requirements of almost all sections of first tea preparation except for a few special types of tea. But energy efficiency differs among different types of machines. The apparatus provides not only heat but also power for tea agitating and rolling and therefore consume both fuel and electricity. Tea machines are now being widely used in the main tea growing areas in China.
3
Machines, the lowest was only 49% of the highest. In another region: Yingshan County, Hubei Province, the old type of tea baking stoves there wasted 40% of energy compared with the energy-efficient stoves. The second cause of energy waste is poor management. Under the same equipment conditions, the consumption of coal in processing 1 kg of tea is 36% more in Xishan Tea Factory of Yuhang County, Zhejiang Province than in other factories because of the poor management. In a sampling survey made in Anhui Province, it was discovered that among three different management ways, the energy consumption of I kg of tea of Unified-processing was 1.9 kg of coal, while that of Collective Processing was 4.5 kg of coal, and Separated-family-processing was 4.7 kg of coal. The latter consumed 142% more coal than that of the first.
PROBLEMS PRESENTED
Large energy waste, bad ecological effect and hindering tea production are three main problems confronted with in tea processing in rural China. Large waste ~)f enerqy The main causes of energy waste in tea processing are as follows. The first one is low energy efficiency apparatus in tea processing. According to a survey of 17 tea processing plants in 1984 made by Hangzhou Tea High Quality and Energy Conservation Cooperatives Group, the energy efficiency of several types of tea processing apparatus, calculated by the Method of Water Evaporating, differed very much. This showed that many low efficiency machines are still in operation in this area. Table 1 indicates that among the surveyed Trough Shaped Green Tea Sterilizers, the energy efficiency of the lowest was only 31% of that of the highest. While among the Bottle Shaped
Bad ecological effect There are both severe shortage and big waste of firewood resources in most of the Chinese rural areas. According to an investigation in five provinces (Sichuan, Yunnan, Guizhou, Hunan and Jiangxi), the forest resources consumed by wood production accounted only for 15 33%, while that used as firewood made up 47-64%. Tea processing in rural areas uses a large amount of firewood, which makes the shortage of rural energy even more severe and speeds up deforestation. In Yingshan County, Hubei Province, 9,000 tons of firewood is needed every year for tea baking, equals an annual productivity of 36,000 mu (5,929 acres) of forest. In some mountain areas in Zhejiang Province where forest has been damaged rather severely, the villagers still cut 4 tons of firewood for making 1 ton of tea. Moreover, the firewood for tea processing is usually log, much better than cooking firewood which is usually small branches and leaves
Table 1. Survey of energy efficiencyof tea processing machines in 17 plants in Hangzhou Prefecture
Types of machines Trough-shaped green tea sterilizer Rolling-barrel green tea sterilizer Double-pan continuing green tea sterilizer Bottle-shaped machine Drying machine
Number of machines surveyed
Average water evaporated" (kg)
Maximum water evaporated" (kg)
Minimum water evaporated° (kg)
5
3.05
4.25
1.30
5
2.39
2.94
1.79
6
1.96
2.60
1.56
19 20
2.27 1.79
5.34 1.84
1.11 1.00
"Water evaporated by burning 1 kg of coal (20,900 J/kg). Source : The Agricultural Bureau of Hangzhou Prefecture, Zhejiang Province (1984). Summary of the Second Conference ¢71Hangzhou Tea High Quality and Energy Conservation Group, March, 1984.
JI Q1N NI and HANGZHOU in these areas. Thus it has caused a greater negative effect on forest resources.
Ra&in9 the cost of tea and h&derin9 the development of tea production The large amount of energy consumption makes up a certain part of the tea processing cost. In some regions it reaches about 10-15% of the gross cost of tea, equals the costs of fertilizer and pesticide in tea growing. Moreover, tea production is effected by the shortage of energy in some tea growing regions. Besides the market, energy is one of the main factors that hinders tea production.
MEASURES TAKEN TO SOLVE ENERGY PROBLEMS IN TEA PROCESSING
Tea has a rather important position in rural economy in China. If the tea production is to be developed, the problems of energy must be solved. This has already attracted more and more attention in recent years and much effort has been made in energy conservation.
A brief history of energy conservation in tea processing Although tea making has a rather long history in China, its energy saving was not largely considered until about ten years ago. In 1950s and 1960s the energy consumption in tea processing was almost totally ignored. In 1970s energy saving in rural areas began to take place especially in firewood saving in the daily life (by using energy efficiency stoves), but not in tea production yet. With a heavy burden of the increasing rural population, the rural biomass energy resources could not meet the needs of both living and production, and caused a severe problem of deforestation. Since the beginning of 1980s, efforts were made in order to reach an economic and ecological goal. At first, technical researches were carried out, pilot programs were launched. Later regional projects were gradually established. In Hangzhou Prefecture, a three-year-plan was made in 1988 in order to improve 80% of the existing tea processing stoves and machines. In May 1989, the first National Conference on Energy Conservation on Tea Production organized by the Ministry of Agriculture was held in Hangzhou, Zhejiang Province. It promotes largely the activities in this field in the whole nation. Under the Ministry of Agriculture, different institutions are involved in the campaign. Among them are : - - T h e Agricultural Bureaus in the levels of province, prefecture and county, usually there is a division
in charge of tea production technologies in each Bureau ; - - R u r a l Energy Offices in different levels, to them the main task assigned is the R/D of rural energy saving and exploitation technologies ; --Local Supply and Marketing Cooperatives which are involved in the tea market. There are also others not under the direct leadership of the Ministry of Agriculture, namely : --Institutes and factories relating to tea machine design and fabrication ; ---Coal companies that supply part of the fuel for tea making.
Efforts made for energy conservation It is estimated that the potential of energy conservation in tea processing is about 220,000 tons of CE a year in rural China. In order to realize the energy saving goal, effective effects have been made in recent years in different regions and different levels. Scientific research and technical innovation are carried out with good results, giving the possibilities to technical improvement of the equipments. Surveys and studies are made for regional planning and policy making. Investments are usually given in different levels: local governments, organizations, rural communes and users. Among them, investments of local governments and organizations are mostly used for research, development and diffusion, while that of rural communes are usually given as subsidies to the users. But these investments are not always available in all regions. Diffusion is also an important part of the work done. Many technical visits are made and technical training courses are held in different levels. Technically, the efforts made for energy saving in tea processing can be summarized as follows : 1. Stove improvement. It is to improve the fuel burning system of fire box as to raise the energy efficiency of the apparatus. It is technically simple, low cost and effective. Improved stoves can raise energy efficiency up to 20-50% compared with that not improved. The cost of the reform can usually be recovered within 12 years. 2. Machine improvement. Comparatively complex and usually done in tea processing machine-making factories, it is to reform the heat-utilizing system in order to raise the heat efficiency. The energy saving rate can usually reach 15-20%. The machines improved are mostly big and medium size tea processing equipment, and therefore have a good result of energy conservation.
Energy consumption and conservation in tea processing in China Table 2. Results of energy saving by adjusting matching power motor of tea machines
Type of machines 6CS-70 Trough shaped green tea sterilizer 6CYS-40 Plane-round screen machine Screen machines conveyer 6CED-45 vibrate screen machine 6CZS- 120 Color-making machine 6CRQ-30 Rolling machine
Original motor power (kW)
Maximum power consumption measured (kW)
1.5
Motor power adjusted (kW)
Energy saving (%)
1.1
27
1.1
0.36
0.8
27
0.55 1.1
-0.4
0.37 0.8
33 27
2.2
0.93
1. l
50
10.0
6.0
7.5
25
Source: Tea Machine Design and Research 4 (1986).
3. Matching power adjustment. It is to adjust m a t c h i n g power o f m o t o r s for tea machines. It is reported that a n overall power d e t e r m i n a t i o n of some tea processing m a c h i n e s revealed a waste o f power of the motors, which is 1.6-3.5 times as m u c h as the m a x i m u m power needed. W h e n the m a t c h i n g m o t o r s were replaced, 2 5 - 5 0 % of the power was saved. See T a b l e 2. 4. Heat using system improvement. In ways o f heat utilization, centralized-heat-providing is energy efficient. In this system, the high temp heat from the b u r n e r is used by the high temp processing section to de-enzyme tea at first, a n d then the wasted low temp heat is used to the low temp processing s e c t i o n - drying. T h e 6 C M C L - 1 0 M o d e l G r e e n Tea First Prepa r a t i o n Set, developed by Z h e j i a n g Agriculture University (1987), using the m e t h o d of Multiple-machines-one-stove, can save 4 0 - 5 0 % o f fuel. 5. By improving management in tea processing. A m o n g the various m a n a g e m e n t ways, unified mechanical processing is m u c h more energy efficient t h a n decentralized m a n u a l processing. In Nigdu Prefecture, Fujian Province, unified first p r e p a r a t i o n o f tea cut d o w n m o r e t h a n a half o f the fuels a n d electricity, the former also saved m a n p o w e r , raised tea quality a n d h a d a better profit. The survey m a d e in H u i z h o u Prefecture, A n h u i Province, proved the same p h e n o m enon. REFERENCES
1. Anonymous, Recent development of the improvement of the Horizontal-pipe Hot Air Stove for tea drying machine. Tea Machines Design and Research 3 (1987). 2. S. Chen, Research on the prospects of tea machine making industry in Zhejiang Province. Tea Machines Design and Research 3 (1987).
3. Z. Fang, Tea Making Double-Stove .[or Saving Enerqy and Raising Tea Quality. Report (1988). 4. The Agricultural Bureau of Hangzhou Prefecture, Zhejiang Province. Summary of the Second Conference of Hangzhou Tea High Quality and Energy Conservation Group (1984). 5. W. He, Saving tea making energy. Tea Bulletin 3 (1984). 6. P. Hu, On the problem of tea-making energy conservation in Zhejian Province. Tea 3 (1983). 7. International Tea Committee. Annual Bulletin of Statistics (1982, 1984, 1986, 1988). 8. L. Jing and P. Lu, Report on the survey of utilization of forest energy in southern China. Proceedings of the Symposium of Forest Energy (1981). 9. J. Liu, A new energy saving stove for tea baking. Tea Bullethls 2 (1987). 10. P. Liu et al. Tea Cultivating and Tea Processing. Guandong Science and Technology Publishing House of China (1983). 11. R. Liu and X. Zhuo, Some remarks on solving the energy problems in tea processing in east Fujian Province. Tea Bulletins 6 (1983). 12. National Statistics Bureau, Yearbook ~f Rural Statistics of China o[1986 (1986). 13. K. Pan, Selection of motor powers for tea processing machines. Tea Machines Design and Research 4 (1986). 14. P. Shuai, The Total Quality Control (TQC) in Mei Tea fine making factories. Tea Bulletins 1 (1986). 15. G. Wang, The development of tea production in China. Tea Bulletin 3 (1987). 16. S. Wang, Tea economics. China Tea 6 (1982). 17. D. Xia, The modernization of green tea first preparation machines. Tea Machines Design and Research 4 (1986). 18, G. Yu, Establish a new system of tea circulation by cooperating and improving first preparation. Tea Bulletin 1 (1987). 19. Y. Yuan, Innovation of the stove of the tea drying machine. China Tea 4 (1982). 20. X. Zhuang, Research on the anticipation of tea development during the period of Seventh Five-year-plan. Tea Bulletin 1 (1986).